Forest Management Guide to Silviculture in the Great Lakes-St. Lawrence and Boreal Forests of Ontario

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Preface

This guide should be thought of as a toolbox. Like all tools, the skill of the person wielding it can greatly influence the quality of the result. Successful implementation of this guide is completely dependent on the judgement of a knowledgeable and experienced silviculturalist. Similarly, a tool does not tell you what to do, but helps you achieve a pre-determined goal. The first step to implementing this guide is deciding what kind of future forest you want.

Silviculture is a means to achieve an end. It is ultimately about achieving local forest management objectives in an efficient and predictable manner. Those objectives have shifted over time from timber to ecosystem management, to the extent that integrative thinking has become second nature for most practitioners. The influence of silviculture decisions on ecosystem health and productivity is considered at all stages from strategic planning to implementation.

Effective silviculture can positively influence the forest for decades to come and on many sites we are now realizing those benefits. Ineffective silviculture can do the opposite for equal or even longer periods with some of the most challenging sites to manage caused by less than desirable past practices. To be fair, some of what we may now regard as ‘mistakes’ were once considered appropriate given the best available knowledge and management paradigm of the day. It is not unreasonable to think that some of what we consider leading edge today, will become tomorrow’s ‘mistake’. This fact should not be cause for concern but evidence that a healthy adaptive learning environment is present.

The job of the silviculturalist is a mixture of routine application of time tested treatments and experimentation with novel techniques or sites, interspersed with the occasional head scratching when one or the other does not provide the expected outcome. Our knowledge has progressed to a point where successes far outnumber failures, but cause and effect is not always obvious, nature is messy, and things do not always go as planned. This does not mean we throw our hands up in frustration with the occasional failure, but that we embrace the uncertainty with which we are working, and commit to learning through practice. As long as we never answer “why do you do it that way” with “cause that’s how we’ve always done it” we can be assured that ineffective practices will be identified and effective practices will get even better.

Acknowledgements

Project coordination and lead author Mike Brienesse (MNRF)

The following individuals provided special assistance during various stages of development:

Jodi Hall (MNRF)
Gordon Kayahara (MNRF)
Andrée Morneault (MNRF)
Ren Peterson (MNRF)
Jim Rice (MNRF)
Martin Streit (MNRF)
Laurie Thompson (MNRF)
Peter Uhlig (MNRF)
Shelagh Yanni (MNRF)

The following members of the Silviculture Guide Revision Advisory Team spent countless hours providing constructive advice and reviewing draft products:

Shelagh Duckett (MNRF)
Mike Forrest (EACOM)
Jeff Leach (Tembec)
Alison Luke (MNRF)
John Lawson (Resolute Forest Products)
Tom Maclean (Nipissing Forest Resource Management)
Rob MacLeod (MNRF)
Peter Nitschke (Bancroft Minden Forest Company)
Fred Pinto (MNRF – retired)
Pat Rosebrook (Clergue Forest Management)
Chris Schaefer (MNRF)
Ricardo Velasquez (MNRF)

The leadership and commitment of Joe Churcher and Brian Hillier to evidenced based policy and adaptive management provided an environment for innovation.

Dozens of people provided their time, knowledge, and good humor in the development of individual species direction and the Bayesian Belief Networks that support the direction in this guide. A listing of additional contributors is included in the Background and Rationale Document that accompanies this guide.

The Provincial Forest Technical committee helped steer this project through all stages of development and provided invaluable advice and support.

Illustration and photo credits included with images. Technical edit by Christina Trevisan. Logistical support provided by Gloria Vidal and Fran Paterson.

1.0 Introduction

Silviculture is the science and art of managing forest communities based on knowledge of tree silvics. More particularly, the theory and practice of controlling the establishment, composition and growth of forest vegetation.

This silviculture guide is a revision and amalgamation of four previous silviculture guides (see section 1.5.3). Those four guides were based on earlier guides, research reports, practice notes, and other documents. Appendix 1 provides a discussion and documentation of the history of silviculture guides in Ontario. Much of the knowledge in this guide has built upon what was first presented in these earlier documents. While the scope, presentation, and content of previous guides varied over time and across guides, the common thread was the importance of good silviculture in maintaining a healthy forest and achieving forest management objectives.

This silviculture guide is one of a series of forest management guides used by forest managers when planning and implementing forest management activities. The series of guides provide direction to assist forest managers to decide, for example, what areas of forest to harvest (and equally important, what areas not to harvest), how large the harvest areas should be, and what harvesting and regeneration practices to use in order to protect or enhance environmental, economic, and social values.

Similar to all forest management guides, the mandate of this document is limited to Crown forests, within the Area of the Undertaking (AOU) of Ontario and for any Crown forests outside the AOU for which MNRF has Environmental Assessment approval to undertake forestry activities. The direction and information provided may also be helpful when managing other Crown forests outside of the AOU and private forest lands.

1.1 Purpose of the silviculture guide

The purpose of the silviculture guide is to provide practitioners and forest management planning teams with information and direction to determine which silviculture activities are effective in meeting local forest management objectives.

The guide presents a number of tools (i.e. combinations of treatments) that have a reasonable probability of creating specific future forest conditions given certain site and initial forest conditions. It is the responsibility of the user of this guide to determine what future forest conditions are desirable and to consider what tools are fiscally, socially, or operationally appropriate. This determination is first made during the development of a Forest Management Plan (FMP) through setting of objectives, application of other forest management guides, incorporation of operational realities, and public consultation. Final implementation of this guide relies on the judgment of practitioners to refine and match treatments to local stand/site conditions and realities.

1.2 Content and organization

This guide is comprised of the main text, appendices, and a background and rationale document (in prep). The main text and appendices are included in the printed version. The background and rationale is a separate digital-only document providing background information and rationale for direction.

The main text has a total of 6 sections. The first section is primarily introductory providing definitions, context, and an implementation schedule. The second section speaks to the importance of integrated thinking when making silviculture decisions. The third section provides a brief description of the silviculture practices commonly used in Ontario and serves as an expanded glossary. The fourth section provides further context describing how this guide fits into forest management planning and a discussion of implementation. The fifth section includes the bulk of the direction including categorization of systems, methods, and treatments, example management approaches, and decision keys for the species considered in this guide. The sixth section describes how adaptive management principles have been incorporated including monitoring, guide effectiveness, and key uncertainties. The appendices provide information, best management practices, and an expanded discussion on selected topics.

The background and rationale document includes a description of the information that was used to develop the direction in the guide and the rationale for decisions made. This includes rationale for first order decisions like amalgamating previous guides into a single guide as well as rationale for individual pieces of direction and significant changes from direction in previous guides.

1.2.1 Definitions

This section provides a brief discussion and definition of the terms used in this guide to categorize the direction being provided. Further definition of terms can be found in Section 3 (Silvicultural Practices), and Section 5 (Management Interpretations).

1.2.1.1 Standards, guidelines, and best practices

This document uses the convention established in previous forest management guides (e.g. OMNR, 2010b) to characterize each piece of direction as a standard, a guideline, or a best management practice. It is important to understand the differences between these three terms since they have different implications when implementing this guide. Standards, as described below, should not be confused with regeneration standards, a forest management planning term further described in section 4.1.3.1.

Standard: a component of a guide that provides mandatory direction

Guideline: a component of a guide that provides mandatory direction, but requires professional judgment for it to be applied appropriately at the local level

Best management practice: a component of a guide that suggests a practice or strategy to help implement the overall purpose of the standards and guidelines

Standards must be followed as written; there is no room for interpretation on the part of the planning team. Guidelines are also mandatory and must be followed, but require professional expertise and local knowledge in order to be implemented. They may be expressed as a range of values or may need to be implemented in different ways according to the site conditions or circumstances encountered. Best management practices are not mandatory direction, but are examples of practices that the planning team may wish to use. The list of best management practices is not intended to be exhaustive; planning teams and field practitioners may think of and implement other ideas or strategies. There is no requirement to use any of these best management practices, and a specific best management practice may not be applicable to local circumstances.

The guidelines and best management practices will be used by planning teams to assist them as they develop and implement silviculture prescriptions specific to their management unit and circumstances. They are neither written nor intended to be copied word for word from the guide into a forest management plan.

The symbol below is used within this document to highlight standards and guidelines. Any other text, tables, figures, numbers, or examples within this guide, including appendices, that are not clearly identified as a standard or guideline using this symbol, should not to be construed or interpreted as such, regardless of how the text is worded.

1.2.1.3 General standard site type

Term and condition 94 of the 1994 approval of MNRF’s class environmental assessment for timber management on Crown lands in Ontario (MOEE 1994) formalized the concept of, and requirement for, a general standard site type to be used in developing silviculture ground rules. The intent of the general standard site type was to provide a common classification and labelling of similar sites across the province. Previous silviculture guides used regional ecosites as the general standard site type.

This guide maintains the use of a general standard site type and adopts the provincial ecological land classification (OMNR, 2009) as the basis for aggregating similar site types. The general standard site type language used in this guide adopts the broad soil groups corresponding to the first order sort of the ecological land classification (Figure 1a). These broad soil groups then become the language used when a differentiation in site type is required to express how a tree species responds to site characteristics and management treatments. Direction is not provided individually for each broad soil group, but rather further aggregated based on the variable (e.g. depth, texture, moisture) of influence. When site type does not have a strong influence on what treatments are recommended, no differentiation by broad soil group is included.

Increasing fertility and carbonates

1.3 Legislative and policy context

The two key pieces of legislation that govern forest management on Crown land in Ontario are the Crown Forest Sustainability Act (CFSA) and the Environmental Assessement (EA) Act.

The CFSA requires the development and distribution of four regulated manuals, two of which give legal context to forest management guides, including this one. The Forest Management Planning Manual (FMPM) requires that forest management guides, including this Silviculture Guide, be used during the preparation of a forest management plan. Similarly, the Forest Operations and Silviculture Manual lists the various policies, including the forest management guides, that relate to forest operations on Crown land.

Using the forest management guide during the planning and implementation of forest management activities is also a legal requirement under MNRF’s class environmental assessment approval for forest management on Crown lands in Ontario as set out in Declaration Order MNRF-71, as amended by MNRF-71/2, under the Environmental Assessment Act (Condition 38a). Other parts of Condition 38 include posting the status of current guides on the internet; reviewing and where necessary, revising each guide at least every five years; reflecting up-to- date scientific knowledge in the guides; where feasible and with the advice of the Provincial Forest Technical Committee, pilot testing new direction before it is finalized; describing the approach to the effectiveness monitoring program that will be implemented for the new guide; and providing opportunities for public review of draft guides, most notably Condition 31, the continuation of a program of scientific studies to assess the effectiveness of the guides, and condition 37, the maintenance of the Provincial Forest Technical Committee as a public advisory committee to the Assistant Deputy Minister, Policy Division with respect to content of and changes to forest management guides.

There is also other provincial and federal legislation that must be followed during forest operations (e.g. Endangered Species Act 2007). If there are inconsistencies or gaps between federal or provincial legislation and the direction in this guide, however, the legislation will always take precedence.

1.4 How this guide was developed

Forest management guides are regularly reviewed to ensure they reflect current scientific knowledge as it applies to Ontario. Among other things, a review considers the results of applicable scientific research and monitoring programs, advances in analytical and operational technology, and consistency with the current implementation of sustainable forest management concepts. This guide was initiated based on the recommendations of reviews of four previous silviculture guides (see section 1.5.3) in 2005 and 2008.

After some initial scoping with practitioners, planners, and the Provincial Forest Technical Committee (PFTC), an Advisory Team was formed to assist in the amalgamation and revision of the then four silviculture guides into a single guide. The purpose of the Advisory Team was to provide a detailed review of the draft guide and associated products, advise on issues and areas of disagreement as they arise, and provide oversight on practical and administrative linkages between the silviculture guide, the forest management planning system, operational realities, and basic common sense. The Advisory Team included 6 members representing Sustainable Forest Licence holders and 6 members from MNRF. The members represented a broad spectrum of experience including silviculture operations, silviculture planning, forest management planning, SFL management, applied research, monitoring, and policy development.

In addition to reconciling the different approaches in each of the four previous guides, a large part of the amalgamation and revision process was the synthesis of available knowledge to support decision making. This included both empirical information from research and monitoring, as well as experiential knowledge from practitioners. To facilitate the combination of these potentially disparate sources of evidence, Bayesian Belief Networks (BBN) were employed. A BBN is a graphical model that portrays the probabilistic influence of relevant variables on a specified goal (e.g. a future forest stand). It is a simple way of showing how different variables interact and cause specific outcomes. In basic terms, trees need soil, water and light and our silviculture treatments influence soil, water and light in different ways. The BBNs developed to support this revision attempt to describe the probability of reaching certain future forest conditions given our knowledge (experiential and empirical) of a trees requirements for soil, water, and light, and how our silviculture treatments influence soil, water, and light.

The BBNs were initially developed based on expert knowledge, and then augmented with empirical knowledge where it was available. The BBN development process generally included a multi-day workshop with experts, followed by an independent review of empirical information (e.g. literature) designed to test the assumptions being made by the experts. The expert BBN was then reconciled with the empirical review with variables, states, relationships, and probabilities adjusted based on the empirical evidence either confirming or contradicting the view of experts. Where no empirical information was available, the experts view was untouched.

The BBN framework allows for the inclusion of incomplete knowledge and forces the user to be explicit about the assumptions they are making. Each of these assumptions then become testable hypothesis to be applied in an adaptive management framework. The BBN provides a description of how we think the system works, highlights areas where our knowledge is rich or incomplete, and demonstrates the critical uncertainties that may lead to different conclusions in terms of recommended management direction. A more fulsome introduction to BBNs can be found in McCann et al. (2006).

Over the course of the revision, multiple drafts of this guide were developed and reviewed by PFTC, the Advisory Team, and interested silviculture practitioners. This included not only the written product, but the information that supported it. Subsequent drafts incorporated the input received during review of the previous draft eventually leading to pilot testing of the draft direction.

Pilot testing was conducted by 3 mock-forest management planning teams, one in each of the 3 MNRF administrative regions. Pilot test teams completed a number of exercises designed to evaluate both the efficiency and effectiveness of the revised guide. Results of pilot testing revealed a number of areas for improvement, including improved integration with the forest management planning system, which have been incorporated into this draft.

1.5 Integration with other guides and implementation

1.5.1 Integration with other guides

This guide is part of a series of forest management guides that collectively direct sustainable forest management practices. It is necessary to consider the direction in the other guides while implementing this guide.

Silviculture decisions on any given site need to consider what is silviculturally possible, what other objectives have been set for the site (e.g. maintain residual forest), and how the sum of silviculture decisions on all sites contributes to achieving landscape level objectives (e.g. increase the area of white pine).

On some sites, the direction in other guides may require the practitioner to make a choice between no harvesting, re-evaluating the future forest objective, or choosing a low probability treatment, method, or system (refer to section 5.2 for definitions). Choosing a low probability treatment, method, or system will add some additional planning and monitoring requirements as described in section 6.2.2 and 6.2.3.

1.5.2 Implementation

This guide will be used in the preparation of phase I forest management plans that come into effect on or after April 1, 2018 and phase II plans that come into effect on or after April 1, 2017. Plans that come into effect prior to these dates may choose to use all, part, or none of the direction in this guide at the discretion of the planning team.

Amendments to phase I plans that came into effect prior to April 1, 2018 or phase II plans that came into effect prior to April 1, 2017, may choose to use all, part, or none of the direction in this guide at the discretion of the planning team. The decision to use this guide or continue to follow the direction used when the plan was originally written will be made locally and should reflect the circumstances, scale, and reason for the proposed amendment.

Contingency plans will use the silviculture guide(s) that were used in the development of the long-term management direction of the plan from which the contingency is being drawn.

Where direction in this guide overlaps with direction included in the tree marking guide (OMNR 2004), this guide takes precedence.

1.5.3 Previous guides replaced

This guide replaces the following forest management guides:

• Silvicultural Guide to Managing for Black Spruce, Jack pine and Aspen on Boreal Forest Ecosites in Ontario (1997)
• A Silvicultural Guide for the Great Lakes-St Lawrence Conifer Forest in Ontario (1998)
• A Silvicultural Guide for the Tolerant Hardwood Forest in Ontario (1998)
• Silvicultural Guide to Managing Spruce, Fir, birch , and Aspen Mixedwoods in Ontario’s Boreal Forest (2003)

Although no longer the source of planning direction, these guides remain a valuable source of information suitable for future reference.

1.6 Consideration of MNRF’s Statement of Environmental Values

In 2008 the MNRF revised its Statement of Environmental Values (SEV) under the Environmental Bill of Rights (EBR). The SEV is a document that describes how the purposes of the EBR are to be considered whenever decisions that might significantly affect the environment are made in the Ministry. The Ministry has considered its SEV during the development of the Forest Management Guide to Silviculture in the Great Lakes St. Lawrence and Boreal Forests of Ontario. This document is intended to reflect the direction set out in the SEV and to further the objectives of managing our natural resources on a sustainable basis.

2.0 Integrated management

This guide provides information on which silviculture practices are likely to be successful in managing or creating a stand with specific composition and structure (i.e. what works). It does not however indicate if that composition and structure will provide good habitat, specific timber yields, meet broad management principles (e.g. CFSA, 1994) or provide any other myriad of desired benefits (i.e. what do you want).

The direction in other forest management guides, combined with broad principles (e.g. large healthy diverse forests), and the forest management planning process (including consultation), will help planning teams articulate specifically what benefits are desired. This normally includes both aggregate level targets that silviculture practices need to contribute to (e.g. harvest volume), as well as prescriptions for what activities can occur, or what type of forest must be retained, in any given area.

This section provides a discussion of the importance of integrating these principles, management objectives, prescriptions, and other desired benefits into silviculture planning and decision making with specific reference to the conservation of biodiversity, timber management, genetic resources, resilience in a changing climate, forest health, and invasive species.

2.1 Silviculture and the conservation of biodiversity

In Ontario, the conservation of biodiversity at landscape, stand, and site scales is addressed during the planning and implementation of forest management operations using a nested coarse and fine filter approach (e.g. OMNR, 2010a, 2010b, 2014). The coarse filter component ensures that a diversity of habitat conditions are maintained across management units (MUs) at a variety of spatial and temporal scales in a mixture that approximates what natural disturbance regimes would produce to provide habitat for all native plant and animal species. This is often referred to as the Emulating Natural Disturbance approach. The fine filter modifies the coarse filter to create more habitat for specific species than might be produced by the coarse filter alone, to mitigate potential adverse effects of operations on individual species, and to ensure the conservation of soil and water resources.

This section describes how direction in the forest management guides that address biodiversity may constrain normal silviculture practices and, in broad terms, how silviculture practices may be modified to meet the objectives of these guides.

2.1.1 Composition

This guide (in concert with other resources such as OMNR, 2004) is essential to achieving objectives in the Landscape Guides (OMNR, 2010b and 2014) as it identifies the silviculture practices necessary to perpetuate or create the desired mix of forest communities within each management area. Planners need to ensure that the silviculture options selected from this guide provide adequate tools to meet any targets developed through application of the Landscape Guides.

In addition, Large Landscape Patches (OMNR, 2010b and 2014) or other Emphasis Areas (OMNR, 2010a) may be identified as landscapes where forest management operations will be modified to maintain or enhance habitat (e.g. white-tailed deer, moose, woodland caribou). Modified silviculture approaches may be required to meet specific habitat requirements (e.g. maintenance of browse in strategic locations).

The influence of silviculture on composition needs to be considered both in terms of the relative amount of different forest units and the diversity within forest units (e.g. OMNR, 2010a – Section 3.2.1). Thus, in forest communities that are normally dominated by few tree species following a natural disturbance (e.g., jack pine forest on deep outwash sands), silviculture practices should normally strive to maintain this low diversity condition. Conversely, in forest communities that are normally dominated by a variety of tree species following a natural disturbance (e.g., mixedwood forest on coarse loamy soils), silviculture practices should normally maintain this high diversity condition. When considering diversity, timing of assessment should also be taken into consideration. The diversity at a young age may not be reflective of the diversity at a later development stage after the net effect of inter-stem competition and other stand dynamics are taken into account.

It should be noted that the direction in this guide is primarily a coarse filter, focusing largely on the tree species present. When specific shrubs, herbs or mosses are an important component of desired communities, this guide provides little direction for their direct management. In these cases, the silviculturalist will have to consider the conditions associated with the possible coarse filter approaches, and design their own fine filter adjustments as necessary, using the best available information.

2.1.2 Structure

Various structural aspects of the forest community influence the variety of plant and animal species present. Three structural components that forest managers have direct control over during silviculture operations are retention of; residual patches, individual trees, and downed woody material.

Residual patches are commonly described as unharvested (or partially harvested) groups of trees retained within or adjacent to harvest areas. They may fulfil a variety of ecological functions for a range of plants and animals, including facilitating movement across harvest areas, providing refugia for species that will recolonize the regenerating harvest area, and providing future patches of old growth forest within regenerated stands (see Rosenvald and Lohmus, 2008). When other forest management guides require the retention of residual patches, forest managers will have to carefully evaluate how silviculture treatments can be used to meet these requirements and equally any constraints on the timing and eligibility of future treatments.

Individual trees are normally retained in a harvest area for ecological, silvicultural, and/or operational reasons. Retention for silviculture and operational purposes is discussed in section 2 and section 5. The following text is specific to retention of individual trees for ecological purposes, commonly referred to as wildlife trees (e.g. OMNR, 2010a).

Wildlife trees are individual trees or small clusters of trees retained within harvest areas to provide specific ecological functions immediately after harvest and/or into the future. These functions include nest or den sites, perch or roost sites, and feeding sites for species using recently harvested areas (see OMNR, 2010c). Some trees are expected to survive and become future supercanopy trees; other trees are expected to die and become standing dead and eventually downed woody material (see below). Forest management guides (e.g. OMNR, 2010a) specify the number, size, and types of wildlife trees to retain in different silviculture systems (or stages of management).

To implement wildlife tree requirements, managers are encouraged to identify the specific types of wildlife trees to be retained in different Forest communities (or groups of Forest communities) to meet objectives considering habitat functions, worker safety, and wind firmness. Within the limits set out in other guides (e.g. OMNR, 2010a), some customization is allowed to ensure the mix of wildlife trees prescribed is consistent with the proposed silviculture treatment package and desired future forest condition. For example, when aerial tending is part of the treatment package, a combination of stubbing (cutting a live tree well above normal stump height [i.e. 3-5 m]) and clumping of residual trees (where permitted) may improve access for spray aircraft by creating more open airspace. Similarly, where there is flexibility on the choice of species, if the regeneration objective is pure conifer, it may be counterproductive to retain hardwoods (e.g. white birch) that will act as a seed source.

Downed woody material (DWM) refers to the twigs, branches, boles, and stumps of trees on the forest floor (OMNR, 2010a). DWM can provide many ecological functions including contributions to nutrient cycling and soil formation, micro-sites for regeneration, erosion prevention, and nest, display, feeding sites, cover, and travel corridors for a wide variety of species (see OMNR, 2010c). The amount of DWM in a regenerating stand is a function of the amount of pre-harvest DWM, the impact of the harvest operation on pre-existing DWM, the volume of logging residue left on site, and the density of residual trees, which represent future recruitment of DWM. The latter 2 are largely determined by logging method (i.e. fulltree vs cut- to-length or tree length) and utilization.

Excessive retention of logging residue or residual trees may interfere with renewal or tending operations, ultimately affecting the achievement of both silviculture and biodiversity objectives. Further, logging slash, particularly when suspended and not in ground contact, can increase the fire hazard. The potential conflict between retention of DWM and achievement of silviculture objectives may require a shift in the preferred regeneration approach when unavoidable.

It should be noted that the Landscape Guide (OMNR 2010b, OMNR 2014) equates structure to age class structure. The suitability of different silvicultural approaches to contributing towards Landscape Guide targets will have to be considered carefully. The steps involved in matching the management interpretations in this guide with forest management planning objectives are outlines in section 4.1.1.

2.1.3 Site level biodiversity prescriptions

At finer spatial scales, key habitats and habitat features required by a diversity of species are addressed through a variety of Area of Concern (AOC) prescriptions or Conditions on Regular Operations (CRO) (see OMNR, 2010a). In some AOCs, all silviculture operations are prohibited while in other AOCs, some may be permitted. In some of these cases, regular harvest, renewal, and tending operations are permitted if conducted when there is little risk of adversely affecting the value being addressed. For example, regular operations are permitted within some portions of the AOC for bald eagle nests if conducted outside the nesting season. In other cases, the type of harvest, renewal, or tending operations that are acceptable may be limited by prescribed stand structure targets. For example, silviculture operations in the outer portion of the AOC for large great blue heron colonies must retain residual forest (OMNR, 2010a).

Although the FMPM (2009) does not include a requirement to follow silviculture ground rules within AOCs^{footnote 1[1]}, there is an expectation that any silviculture operations will carefully consider their effect on the future condition of treated stands. While the primary objective is to develop and implement operational prescriptions that prevent, minimize and mitigate adverse effects on the value addressed by the AOC, operations should, to the extent practical and feasible, be consistent with OMNR’s emulation of natural disturbance philosophy and a forest management plan’s overall objectives for conserving biodiversity. In some cases, this will require that operations replace the initial stand with one of a similar composition and structure, whereas in other cases, stand conversion to a different FU or stand structure may be acceptable or preferred. For example, within woodland caribou range, it is not desirable to use silviculture practices within AOCs that will convert conifer-dominated forest to mixedwood or hardwood forest. Although it may not always be possible, when AOC prescriptions preclude standard silviculture treatment packages, creative alternative treatment packages should be considered. At the same time, it needs to be recognized that some AOC prescriptions may not be compatible with some future forest objectives. For example, retention of mid-story cedar and balsam fir as critical thermal cover will make it very difficult to regenerate white pine on most site. When restrictions within AOCs do not allow the target composition or structure of the future forest to be achieved, excluding all operations may be the best choice.

2.2 Timber management

The shift from exclusively timber management to ecosystem management recognizes the value of other benefits from the forest (habitat, carbon storage, cultural resources, etc.) and reduces the potential negative impacts of an exclusively timber focus. However, this shift does not discount the continued importance of managing the forest to produce timber as one of many benefits of a healthy forest ecosystem. This section briefly discusses the integration of timber management principles into silviculture planning and decision making.

2.2.1 Crop planning and strategic silviculture

Crop planning is a process of custom designing and optimizing the density of regeneration, the timing and intensity of stand-tending treatments, the timing of future harvests, and the selection of trees for retention (when applicable). For crop planning to be effective it must be applied at both strategic and operational levels, with one providing context for the other.

During strategic planning it is necessary to identify the different silviculture treatments that are possible, the cost of applying those treatments, and the expected success in achieving a specific future forest condition. In identifying these inputs a number of assumptions must be made about the specific treatments being applied. Using a crop planning approach forces the manager to explicitly state and evaluate assumptions about forest stand behaviour over time and in response to treatments. Rather than basing these inputs on broad concepts of renewal pathways, specific detailed scenarios are developed (exact treatment pathways on fictitious sites) and then aggregated into the model inputs. This explicit process forces the silviculturalist to justify silviculture programs in the context of their cost, relative success rates, and contribution to forest level objectives.

The explicit statement of assumptions at the strategic level, allows for testing and refinement through monitoring of actual results. If the performance of actual treatments is significantly different than projected in strategic modelling there is a risk that objectives will not be achieved and sustainability of the plan may be called into question. By explicitly stating assumptions not only is the initial forecast less likely to vary from the actual results, but when deviations do occur, the discrepancy can be easier to find. For example, the cost, forecast of future condition, and probability of success for a treatment that includes planting would ideally be based on explicit assumptions about how often site preparation is used, the average density of planting, the need for vegetation management, etc. If actual results start to vary each of these assumptions can be compared to what has actually occurred and corrective adjustments can be made.

Crop planning at the individual site level is developing a schedule of treatments that will control stand development to achieve a desired end. In even-aged systems this starts with matching initial establishment densities to a desired end product and then planning required interventions to manage competition and density to achieve the desired result. This process typically involves the use of tools such as a density management diagram, stocking tables, or other ‘calculators’, which are based on empirical data, to balance the number (and cost) of treatments, the desired end product, and maintenance of optimal growth rates.

2.2.2 Management intensity

Management intensity is a label used in Ontario’s forest management planning process to describe different expectations of future timber yield within each even-aged forest units and document the anticipated treatment pathways required to achieve them. Increasing intensity generally means increasing site occupancy, control over species composition, implementation of competition control and density management, and may include improved stock. In general, increased intensity is associated with increased effort/expense, but this is a problematic description of intensity as high effort/expense does not guarantee results will meet expectations. Common management intensity labels include extensive, basic, intensive, and elite but the meaning of these terms can vary significantly from one forest to the other. Bell et al (2011) propose a framework for classifying management intensity including definitions for extensive, basic, intensive, and elite intensities of silviculture.

The forest management planning process involves developing objectives, desired levels, and targets for different forest types over time. Some objectives can be tracked at a coarse level (e.g. area by forest unit or forest unit group) while others require greater resolution. Timber management objectives are commonly expressed as volume by species (or species group) and may include targets for specific products within each group. Management intensity provides additional resolution to track achievement of timber management objectives and verify that harvest, renewal, and tending activities are consistent with achievement of short and long-term management objectives.

2.2.3 Investment considerations

The extent to which timber management is emphasized on any given site is influenced by a number of factors. Common sense combined with sophisticated modelling approaches can be used to help determine the optimum location and arrangement of different management intensities on the landbase. This silviculture guide only deals with site selection as it relates to silviculture success, which may not translate directly to optimal yield or quality, and certainly does not consider location or other factors. The decision on where to emphasize timber management objectives is a separate process not directed by, and only partially informed by, this guide.

2.3 Genetic resource management

Biodiversity can be described as the variety of ecosystems, the variety of species, and the variety of individuals within a species. Genetic diversity is the basic unit of biodiversity - it is the inherited difference between individuals of the same species. Genetic resource management can be defined as the incorporation of genetic principles into forest practices in order to conserve genetic diversity in trees while promoting economic development through maintenance and enhancement of productivity (Joyce et al 2001).

Genetic diversity is important for maintaining healthy tree populations that are able to respond favourably and adapt to changes or disturbances in their environment. Changes to genetic diversity occur through the creation of new genes (through mutation), and the loss of existing genes (through genetic drift in small populations and through elimination of populations).

Humans can affect the rate of change in genetic diversity accidentally or deliberately, such as through the sustained selective removal of individuals in “high grade” selective harvest operations, selection and propagation of certain individuals, or the introduction of new genetic material through movement of genetic material in artificial regeneration operations. Successful and sustainable forest management practices should include maintenance of natural levels of genetic diversity as a priority.

The principles of genetic resource management differ slightly between natural and artificial regeneration methods. Natural regeneration requires the maintenance of a broad genetic base by ensuring that a large number of trees contribute to the regeneration. Artificial regeneration requires control of the seed source to ensure seed/stock is adapted to the seeding/planting site. Tree improvement programs attempt to limit the variation in phenotypic expression while maintaining some genetic diversity. Selective harvesting offers a particular challenge as trees are selected for both size and form which may cause the exclusion of some genes from the future population.

Tree improvement programs are directed at improving the productivity and quality of commercial forest tree species. Strategies for realizing genetic improvements are varied and reflect local choices and responses to geographic, technical, economic, social, and political factors.

Isolated tree populations and scattered individuals, particularly at the outer ranges, need to be considered carefully. They represent opportunity in the potential of unique genetic material but also a challenge in terms of genetic effects when targeting natural regeneration (e.g. selection of seed trees). Population structures that have restrictive habitat requirements, even when local densities are high, are more susceptible to genetic effects (inbreeding depression, genetic drift, etc.) than those with broader habitat requirements (Joyce et al 2001).

2.4 Managing for resilience in a changing climate

2.4.1 Resilience

Ontario’s Biodiversity Strategy (2011) defines ecosystem resilience as the capacity of an ecosystem to adapt to changes and disturbances and still retain its basic functions and structures.

The resilience of a forest ecosystem to changing environmental conditions is determined by its biological and ecological resources, in particular (i) the diversity of species, including micro- organisms, (ii) the genetic variability within species (i.e., the diversity of genetic traits within populations of species), (iii) the functional diversity, species, and redundancy (i.e., not all species are necessarily equally important in maintaining ecosystem processes, and (iv) the regional pool of species and ecosystems. Resilience is also influenced by the size and structure of forest ecosystems (generally, the larger and less fragmented, the better), and by the condition and character of the surrounding landscape (Thompson et al 2009).

Forest ecosystems can be threatened by insects and disease, natural disturbance, changing climate, and many other factors. Management decisions that maintain healthy and diverse forests may be a key strategy for retaining a resilient forest that can endure these threats, including climate change.

2.4.2 Projected climate change

Weather is the condition of the atmosphere (temperature, precipitation, wind, humidity, etc.) over a short period of time in a local area. Climate is the average weather conditions for a given region over a long time period (e.g. 30 years). Climate change is a shift in climate (patterns of temperature and precipitation) relative to a given reference time period.

Climate is influenced by greenhouse gases (e.g. water vapour), ocean temperature cycles (e.g. Pacific Decadal Oscillation), changes in solar output (e.g. Maunder minimum), aerosol particles (e.g. volcanoes) and many other factors. Some greenhouse gases (e.g. CO₂) have increased substantially since pre-industrial times and are projected to continue to increase in the future. Based on projected increases in greenhouse gas concentrations and a number of estimated parameters (water vapour and cloud feedback, aerosol concentrations, sensitivity to changes in radiative forcing, etc.), scientists have used climate models to predict future climate.

A warmer, more variable climate is predicted to be accompanied by regionally altered precipitation regimes and increased frequency of extreme weather (IPCC 2007). Colombo et al (2007) provide an overview of Ontario’s future climate based on the Canadian Coupled Global Circulation Model using two scenarios of future greenhouse gas emissions resulting from human activity in the 21^st century. Temperatures are expected to increase across the entire province with more pronounced warming in the north. The timing and amount of precipitation is also expected to shift, with some regions getting drier, and others getting wetter. Like any prediction of the future, there is a relatively high degree of uncertainty in these estimates with different emissions scenarios, and different climate models, predicting different futures for any specific location. The consensus from the major global climate models, however, is for significant warming, with uncertainty largely focused on the magnitude of warming.

2.4.3 Predicted effects of climate change on forests

Climate has long been identified as a primary control on the geographic distribution of plants (Box, 1981). If climate changes as projected (e.g. Colombo et al 2007), changing environmental conditions and/or the frequency and intensity of disturbances will be an additional stress on ecosystems.

McKenney et al (2007) provide an estimate of future climate niches for 130 North American tree species by determining present day climatic niches and then delineating similar conditions on maps of predicted future climate. This analysis indicates where each species could potentially occur by the end of the century from a climate niche perspective. In general, many climate niches are projected to shift northward at a faster pace than the species’ natural dispersal mechanisms can keep pace with. However, geographic range limits may also be influenced by competitive interactions between fast growing southern species and slower growing northern species (e.g. Loehle 2014) thereby softening or adding a significant time lag to potential temperature effects at the southern edge of the current range.

Even when a species is still within its climate niche, increased temperature fluctuations or periodicity of precipitation may have negative consequences. For example, temperature fluctuations, particularly in spring when trees can de-harden during an early warm spell followed by cold days, can lead to damage and mortality (e.g. Man et al 2009). Similarly late frosts and prolonged droughts can reduce growth and vigor, increase dieback and mortality, and reduce the number of good mast years. Worral et al (2013) list increased summer temperatures and reduced April to September precipitation as significant contributors to a recent decline and dieback of aspen in parts of North America.

Northern forests may initially see an increase in productivity with warmer temperatures and longer growing seasons, provided moisture is not limiting (Boisvenue and Running 2006).

Changes in temperature and precipitation are expected to lead to a drier forest floor. This could increase the potential for more lightning and human caused fires to start and spread. Wotton et al (2005) project a 15% and 50% increase in the number of fires by 2040 and 2090 respectively, with an 80% increase in the number of fires that escape initial attack by 2100. Changes in temperature and precipitation may also influence the distribution of and damage from insects and pathogens (e.g. Sturrock et al 2011). Growth rates, reproductive success, and the distribution of hosts, alternate hosts, and predators may shift with a changing climate. Most insects and pathogens will be able to migrate at a faster rate than tree species and their shorter life cycle may allow them to adapt more quickly to changing conditions.

2.4.4 Adaptive silviculture

Managing forest ecosystems to maintain or restore ecological resilience may make them less vulnerable and better able to cope with the stresses from climate change (Parker et al. 2012). Fundamentally, managing for resilience is about conserving or enhancing biodiversity at genetic, species, and population scales to maintain ecosystem processes and complexity at multiple scales, while meeting management objectives.

Sustainable forest management on Crown lands in Ontario includes a number of practices that promote forest resilience (maintenance of biodiversity, protection of sensitive sites, use of local seed sources, maintenance of structural complexity at multiple scales, etc.). Direction in the Landscape (e.g. pattern class targets) and Stand and Site Guides (e.g. structural legacy), along with decisions made through the forest management planning process, contribute to the resilience of the future forest.

Silviculture practices have the potential to influence future resilience by directly and indirectly influencing future composition at a species and genetic level. Direct effects include favouring specific species or genotypes through artificial regeneration, tending, compositional treatments, and selective harvest. Indirect effects involve manipulation of environmental conditions (light, soil temperature, etc.) that may favour one species or genotype over another.

There is no specific prescription or direction included in this guide to respond to climate change; however, the forest manager is encouraged to employ an adaptive and flexible decision-making framework that incorporates new knowledge and experience over time. Given the uncertainty of both the extent of climate change and an ecosystem’s response to the changes, “no regrets” adaptation tactics that result in a wide variety of benefits, and choosing practices aimed at promoting the natural adaptive processes of ecosystems that enable them to accommodate and respond to change should be considered (Parker et al. 2012, Millar et al. 2007).

Evaluating if a particular adaptation tactic is “no regrets” is complex and will require careful consideration of a number of factors, not the least of which is satisfying a basic assumption that the new approach will have a higher probability of success than the current. For example (adapted from Swanston and Janowiak, 2012):

• Likelihood of Success – Is an adaptation tactic likely to be effective in the future across a variety of potential conditions? Will implementation of an adaptation tactic help achieve existing management objectives and goals?
• Trade-offs – What are the potential trade-offs associated with selecting and implementing a tactic? If you select an adaptation tactic, will there be negative consequences on other parts of the ecosystem or on other management actions? Can adverse impacts be avoided or mitigated?
• Urgency – Is there a need to implement an adaptation tactic in the near term? Will implementing a tactic now provide clear benefits in the future?
• Cost – Does an adaptation tactic have a high financial cost? If there are no new funds, what other items will not occur? Will implementing a tactic now prevent greater costs in the future?
• Effort - Is the adaptation tactic labour- or time-intensive? If there is a limited pool of labour resources, what other activities will not occur? Will implementing a tactic now reduce the amount of work needed in the future?

Individual forest management planning teams may determine that specific adjustments to standard forest management practices to enhance or maintain resilience are desirable. Careful analysis of the interaction with other guides (e.g. Landscape Guide composition targets) and policies (e.g. seed zones) is advisable before proceeding.

2.5 Forest health

Section 2.1 includes a discussion of integrating the conservation of biodiversity into silviculture planning and activities. That biodiversity includes forest insects and pathogens that play a vital role in ecosystem dynamics and in themselves contribute to the diversity in our forests. The majority of insects and disease cause only minor or localized impacts; however, the influence of some insects and pathogens can be significant enough to compromise achievement of other objectives in the forest.

Silviculture activities have the potential to influence the susceptibility of forest communities to various insects and pathogens. Silviculture activities can change the overall stand vigor, manipulate habitat conditions (e.g. humidity) for the insect/pathogen, change the diversity of tree species present, or manipulate habitat for secondary organisms. Each insect/disease is unique, and the influence of silviculture activities on their development, prevalence, spread, and severity of impact is varied. Silviculturalists should make themselves aware of the insects/diseases in their local area, and consider the potential influence of silviculture treatments on the role of insects and pathogens in the ecosystem. A listing and brief discussion of insects and pathogens relevant to the tree species addressed in this guide can be found in Appendix 3 (factsheets) and Section 5.1 (summary and suggested management approaches by species).

2.6 Invasive species

The health and biological diversity of Ontario’s forests are threatened by the introduction and spread of a variety of invasive insects, plants, and diseases. Invasive species often have no natural enemies, can develop unchecked, and have long-term impacts on forest composition.

Some affect trees directly (e.g. emerald ash borer, beech bark disease, chestnut blight, white pine blister rust) while others may influence the regeneration environment (e.g. dog strangling vine). Silviculture activities have the potential to influence the establishment, spread, and persistence of invasive species in positive and negative ways. Where relevant, invasive insects and pathogens are addressed in the information and direction for individual species in section 5.1.

In addition, silviculturalists should apprise themselves of the latest information for invasive species known or expected to occur in their area. Various sources may be consulted for the latest information on how to identify and control invasive species such as the Canadian Forest Service’s Forest Invasive Alien Species of Canada website and the Ontario Federation of Anglers and Hunters’ Invading Species Awareness Program website.

3.0 Silviculture practices

Silviculture practices are treatments applied at the stand scale to achieve specific forest management objectives. Treatments are broadly categorized as either harvest, renewal, or tending. Ideally these practices are applied in a coordinated fashion with a long-term view of what is possible, practical, and desirable at both a stand and landscape scale. The coordination and long-term view is achieved through application of a silviculture system.

The following text provides a description of the silviculture systems, harvest methods, logging methods, renewal treatments, and tending treatments typically applied in Ontario and considered in this guide.

3.1 Silviculture systems

A silviculture system is a planned program of silviculture treatments that extends throughout the life of a stand for the purposes of controlling stand establishment, composition, and growth (Smith et al 1997). While this view implies a certain intensity of effort and manipulation, on suitable sites the simplest application may include only a single harvest with natural regeneration (assuming a seed source, seedlings or root suckers are present in sufficient quantity to restore the forest to a desired composition and structure).

The concept of silviculture systems emerged in Europe after the “wood famines” of the 17^th and 18^th centuries. The systems were developed in an effort to classify, document, and share a large body of local knowledge. Over time the accepted systems developed into a “toolbox” that local managers could apply and adapt to their specific social, economic, and ecological realities (Puettman et al 2009). These somewhat standardized tools allowed what was learned in one location to be transferred to another, eventually being transferred from Europe to North America.

As silviculturalists continue to innovate and introduce new (or revived) practices, particularly harvest practices, they are commonly fit into one of the three traditional silviculture systems (selection, shelterwood, and clearcut). In some cases, it is difficult to assign a new practice to the appropriate silviculture system, largely due to a lack of a clear, quantifiable, and unique definition. As well, some suggested practices do not fit well into any of the three single traditional systems (e.g. matching the regeneration approach of one system but the future age class structure of a different system).

While recognizing some limitations, silviculture systems are further modified to ensure the structure and composition of a forest after a logging operation more closely matches or emulates the conditions found after fire, wind, or other natural disturbance. Emulation refers not only to an attempt to match the natural disturbance mechanism (e.g. gap development resulting from blow down), but also to the post-disturbance growing conditions to which trees have adapted over millennia. Natural disturbance can be further emulated through consideration of natural fire pattern, function of residual trees, mitigation of adverse effects of machinery, and other requirements as outlined in OMNR, 2010a.

The following text and tables describes the silviculture systems framework used in this guide. The framework is largely based on the traditional silviculture systems but with some elaboration of definitions to provide clarity and represent the full range of possible silviculture practices.

3.1.1 Definitions

Table 3a. Silviculture systems referenced in this guide

The definitions presented in table 3a allow the user of this guide to consistently assign any proposed combination of silviculture treatments into one of three silviculture systems - provided they can forecast the target age distribution, the expected light conditions resulting from harvest(s), the planned duration of overstory retention, and the timing of the regeneration. This assignment becomes important when applying the management interpretations (i.e. recommended silviculture systems for different species) in section 5 of this guide and selecting a silviculture system to achieve local objectives.

3.1.2 Growing conditions created

The clearcut system provides light conditions similar to those following a stand replacing disturbance (e.g. fire) with sheltering of the forest floor limited to logging residues and sparse residual trees. The clearcut system is most suited to light-demanding species (e.g. jack pine and aspen) but can be an option for some shade tolerant species when competition is controlled and shelter for insect and disease control is not required.

The shelterwood system provides an environment of partial shade from a high, evenly- distributed crown canopy, with living seed producing trees, and moderated temperature and moisture conditions on the forest floor. These conditions emulate the environment for which many mid-tolerant species have evolved. Natural analogues may be a non-stand replacing fire or a partial blow down.

The selection system provides an environment ranging from partial to full-shade and a forest floor protected from temperature extremes and desiccation. Regeneration under single tree selection favours shade tolerant species while some mid-tolerant species are well suited to group selection openings.

3.1.3 Variations within silviculture systems

The definitions presented in table 3b include a range of possible growing conditions (e.g. light) within each silviculture system. Variations within each silviculture system include differences in the amount, arrangement, and size of residual trees retained after harvest and the timing of their removal. These variations are commonly referred to as harvest methods (see section 3.1.2.1). Harvest methods may further vary to meet a variety of site specific objectives depending on the amount, size, and function of residual trees retained (see section 3.1.3.2, 4.1, and 4.2).

3.1.3.1 Harvest method

Harvest method is a description of the variation in the amount or pattern of retention within a silviculture system. The level of variation introduced by each harvest method is constrained by the definition for each silviculture system (e.g. % full sunlight). Not all harvest methods are applicable to all silviculture systems. The terminology regarding harvest method has evolved over time with some terms having subtle but important differences when applied in different silviculture systems. Table 3b provides a definition of the harvest methods considered in this guide and the silviculture systems to which they are normally applied.

Table 3b. Description and applicable silviculture system for common harvest methods applied in Ontario.

Figures 3a through 3i provide an illustration of the implementation of the silviculture systems described in Table 3a and their common variants described in Table 3b.

3.1.3.2 Residual tree retention

The harvest methods described in section 3.1.3.1 are categorized based on silviculture objectives and the related growing conditions they create. The growing conditions created are largely a function of the amount and pattern of harvested and retained trees. Harvest and retention decisions are normally tuned to meet silviculture purposes but may also be adjusted to meet other management objectives (diversity, viewshed, etc.) or to address operational considerations.

Often, a single retained tree can be related to more than one of these categories. For example, a large white pine may be left as a seed tree for silviculture purposes, a supercanopy tree for diversity purposes, and an oversized tree if the available equipment cannot process it.

Trees retained exclusively for silviculture purposes may be retained for short or long periods of time depending on the silviculture system being applied and future access to the harvest area. For example, residual trees retained after the first harvest in a shelterwood may be retained for only a few years while residual trees in a selection harvest may be retained for multiple cutting cycles totalling 100+ years. Trees retained exclusively to meet management objectives are generally retained for longer periods, often until natural mortality occurs, unless replacement trees of a similar function are available during a future harvest entry.

Across different silviculture systems the number of stems retained can range from tens (clearcut) to many hundreds (selection) of trees per hectare. Within each silviculture system the range of possible retention is limited to the definitions in table 3b. In some cases, the additional retention associated with diversity objectives and/or operational realities may limit which silviculture systems can be applied or which species can be successfully regenerated. Further discussion of suitable retention levels by species is provided in the management interpretations in section 5.2.

Residual trees above minimum requirements (e.g. OMNR 2010a) might also left after harvest due to market conditions. This occurs when a particular species and/or product is not in demand, or cannot be harvested, processed, and hauled at the current market price. These trees represent not only a lost opportunity from an economic point of view, but can also hinder the implementation of the silviculture prescription, resulting in an increased risk of not meeting silviculture objectives. Too many residual trees can;

• cause excessive shade
• compromise quality improvement targets
• introduce less desirable seed sources (species and genetic quality)
• suppress root suckering (e.g. aspen)
• hinder in-block access for renewal and tending
• create overhead hazards

The quantity, species, and quality of residual trees retained after harvest will be consistent^{footnote 7[7]}with the silviculture objective for the site (Guideline).

In some clearcut harvest operations, trees are removed in stages with different species or products targeted in different entries. This is referred to as two-pass harvest and can have implications on the success of regeneration. The initial harvest entry will increase available light, often disturbs the forest floor, and stimulates regeneration of target and competitor species. Regeneration that is established in the first entry risks being damaged in the subsequent entries. Shade intolerant species may be able to regenerate in the initial light conditions but as light demands typically increase with age, and the remaining canopy expands in response to the harvest release, may die off before the final harvest can occur. On richer sites, non-crop species such as beaked hazel and other shrubs may establish in the partial shade conditions created by the first harvest and inhibit regeneration of crop species, even after the final harvest occurs. The longer the delay between the first entry and completion of the harvest prescription the greater the risk to compromising regeneration objectives.

Two-pass harvest should be avoided where possible. When other factors do not allow a single harvest entry the delay between first and final harvest entries should be less than 2 growing seasons (Best Management Practice).

3.2 Logging method

Logging method is a description of the components of a tree that will be removed during harvesting and the degree of processing that occurs at the stump. The logging methods typically used in Ontario include full-tree, tree-length, and cut-to-length.

Other logging methods such as whole-tree (tree and stump removed) and complete-tree (tree, stump, and large roots removed) are not a wide spread practice^{footnote 8[8]}on crown land in Ontario, generally prohibited by OMNR, 2010a, and will not be considered in this guide.

Table 3c provides a description of full-tree, tree-length, and cut-to-length logging methods.

Table 3c. Description of the three logging methods typically employed in Ontario

(Converted to a definition list)

Full-tree

The removal of the entire crown and bole to the roadside where the tree is chipped whole or limbed and topped with cutting-to- length (aka slashing) occurring at roadside or offsite.

Tree-length

The removal of the main stem to roadside with limbing and topping occurring at the stump and cutting-to-length (aka slashing) occurring at roadside or offsite.

Cut-to-length

The limbing, topping, and cutting-to-length (aka slashing) of trees at the stump followed by removal of the logs to roadside.

Selection of a logging method is complex and requires consideration of many operational realities (available machinery, requirements of receiving mills, etc.) that may constrain short- term flexibility and take many years to change. Equally important, the logging method can influence post-harvest conditions and achievement of short and long-term silviculture objectives. Additional considerations may include:

• Silviculture system employed
• Quantity of in-block slash and influence on future renewal
• Quantity of roadside slash and potential need for treatment
• Impact on desirable and undesirable residual trees
• Impact on desirable and undesirable advance growth
• Concentration of nutrients
• Tree size and operating efficiency
• Site characteristics, silviculture objective, and ground disturbance
• Footprint of extraction trails and roadside work areas

Most of the above considerations can be both positive and negative depending on the situation and it is not possible to generalize. For example, too much in-block slash can be an impediment to operations but can also provide a seed source (cones) for regeneration and a more even distribution of nutrients. Cut-to-length operations can reduce site damage on susceptible sites by using slash mats for travel, while light soil disturbance associated with fulltree logging may provide desirable site preparation on other sites.

3.3 Renewal treatments

Renewal involves a planned set of treatment(s) applied in a coordinated fashion, in one or more successive steps, to establish a defined forest condition. Renewal typically begins with a harvest but can also include pre-harvest treatments (see section 3.6). Treatments are selected to create or maintain conditions that favour establishment, protection, and growth of desired species.

Successful renewal starts with a clearly articulated future forest objective for the site (see section 4) followed by careful upfront planning of renewal operations, including harvesting, that will have a high probability of achieving the future forest objective given the site characteristics, current forest condition, and operational realities. The influence of the harvest treatment on overall success cannot be overstated.

The discussion on renewal treatments is divided into site preparation and regeneration. The following two sections provide a description of each. The descriptions below are somewhat general in nature and provide only an overview of the techniques and some of the factors to consider during planning and implementation. Learning from past successes and failures through dialogue with local practitioners and, detailed recording of operations and rationale behind decisions is critical to long-term success of a renewal program.

3.3.1 Site preparation

The primary objective of site preparation is to create enough suitable, well-distributed microsites for the establishment of desirable species. This involves the disturbance of the forest floor, upper soil horizons, and/or competing vegetation prior to regeneration. In sensitive lowland areas site preparation disturbance of the forest floor may be limited to slash realignment. Treatments include manual, mechanical, chemical, and prescribed burning. These treatments may be used alone or in combination. The treatment may be applied before, after, or between harvest entries.

Within this guide, the previous distinction between site preparation (artificial regeneration) and scarification (natural regeneration) has been removed. The term scarification may still be a useful distinction in the field, but is not used in the management interpretation tables in section 5.2.

Table 3d provides a brief discussion of four general types of site preparation used in Ontario. For an expanded discussion refer to Sutherland and Foreman (1995).

Table 3d. Description of general site preparation techniques commonly used in Ontario

(Converted to a definition list)

Manual

The use of boot/shovel screefing or manual or motor-manual tools to set aside surface litter, suppress undesirable vegetation, or to otherwise prepare microsites for regeneration.

Mechanical

The use of machinery with self-propelled prime movers to prepare microsites for regeneration and may be combined with a herbicide application in a single operation. Methods (shearing, screefing, inverting, mounding, trenching, mixing) vary in the amount of disturbance of the forest floor, degree of mixing of the organic layers with the underlying mineral soil, and influence on existing vegetation.

Chemical

Application of federally registered, provincially approved herbicides by licensed applicators prior to regeneration. This treatment can be used alone or in combination with other types of site preparation or in advance of a prescribed burn (brown and burn). Herbicides can be applied from aircraft (e.g. helicopter), ground machine (e.g. skidder mounted airblast), or using manual tools (e.g. backback sprayer). The pattern of application varies from broadcast to band selective to spot selective to stem selective. A wide variety of chemicals and carriers can be used and no attempt has been made to list them here.

Prescribed Burning

The knowledgeable application of fire to a specific land area to accomplish predetermined land management objectives. Site level objectives are translated into to a desired fire severity and matched to specific fire weather indices (e.g. duff moisture code) based on local fuel conditions. The Prescribed Burn Operations Policy (OMNR, 2008) and the Prescribed Burn Manual (OMNR, 2008) provides the policy, procedures, and planning framework for the application of prescribed burning in Ontario. Appendix 5 includes additional discussion on the use of prescribed burning.

3.3.2 Regeneration

Regeneration is the establishment of a new cohort of trees either by natural or artificial means. Treatments range from passive natural regeneration using self-sown seed or vegetative reproduction (suckers, sprouts, layers) to assisted natural regeneration such as scarification, to artificial seeding and planting. Combinations of both natural and artificial regeneration, known as blended regeneration, may also be used in some circumstances.

3.3.2.1 Natural regeneration

Natural regeneration is the establishment of desired tree species by natural seeding, sprouting, suckering, or layering. The success of natural regeneration depends upon the autecology of the targeted species and competitors, site conditions, and the growing conditions (light, seedbed, etc.) created by prior and subsequent treatments.

Natural regeneration presents an opportunity to maintain local gene pools and reduce operational costs, however, naturally regenerated stands typically have more variable stocking, clumping, and species composition. Further, some natural regeneration approaches require an extended regeneration period, contributing to an increase in the rotation age of the next stand. Groot (2001) provides an excellent review on the use of planned natural regeneration for conifers in Ontario.

Advance growth refers to young trees under existing stands capable of becoming the next crop. Advance growth is composed of species that are mid-tolerant to tolerant of shade and may be a different species than that dominating the overstory. Advance growth can originate from any combination of seed, vegetative layering, root suckers, and stump sprouts and may range in size from small seedlings to larger poles.

Many tree species (spruce, birch, cedar, oaks, white pine, etc.) in Ontario regenerate through the use of seedling banks (seedlings establish under a closed canopy and grow slowly for a number of years, waiting for a canopy opening). In many cases these species establish a regeneration layer before a stand initiating disturbance occurs. This provides an opportunity to utilize this adaptation to establish a regeneration layer before a harvest treatment is initiated or before the majority of the canopy is removed in the case of shelterwood or selection. While advance growth can provide sufficient stocking and distribution of desirable species it is typically complimented with other natural or artificial regeneration methods. When mixed strategies are implemented, there needs to be a realistic evaluation of the value of the advance regeneration - is the density, size, vigor, and survivability of the regeneration high enough to think, that if protected, it will survive and thrive and become part of the new stand? Indiscriminate reliance on advance regeneration can compromise achievement of objectives. Undesirable advance growth (e.g. balsam fir) will not only limit success of other regeneration methods, but contribute growing stock that is not consistent with objectives and contrary to an emulation of natural disturbance paradigm.

Natural seeding is the dispersal by natural means of seeds from standing trees or from cone- bearing slash. Natural regeneration from seed requires the successful completion of a chain of events involving flowering, cone development, seed dispersal, germination, establishment, and early seedling growth. If this chain is broken (e.g. drought limits seedling establishment), it can result in regeneration failure and a delay in renewing the site. Maximum success can be achieved when a good seed year is combined with a suitable seedbed and adequate moisture during the growing season. Site preparation techniques are often used to improve seedbed or other germination and growing conditions. Many Ontario tree species can be regenerated using natural seeding including white birch, yellow birch, red oak, jack pine, black spruce, sugar and red maple, black cherry, larch, hemlock, and cedar.

Good seed years in Ontario vary by species (see Appendix 3 – fact sheets) and may vary regionally in any given year. For some species, good seed years can be predicted in advance allowing coordination of harvest, scarification, or other seedbed treatments with seed fall. Refer to the Seed Manual for Ontario: Guidelines for tree seed crop forecasting and collecting (OMNR, 1996) for further information.

Vegetative regeneration includes root suckers, stump sprouts, and layering. The term coppice is commonly used to refer to both stump sprouts and root suckers. In this guide layering is grouped with advance regeneration (see above). Sprouts may come from a recently harvested parent tree or from seedlings and saplings damaged during operations (e.g. maple seedlings) or intentionally clipped to encourage vigorous re-sprouting (e.g. red oak).

Vegetative regeneration offers many of the advantages of natural seed (maintain local gene pool, high initial densities, improve wood quality, etc.) but also offers rapid early growth due to support from the parent root system. The capacity for vegetative reproduction is strongly influenced by the health (drought, defoliation, pathogens, health, etc.) of the parent root system, diameter of the parent tree, and the suppressive chemical influence of any uncut stems.

Ontario species commonly managed using vegetative regeneration include basswood, trembling aspen, red maple, and red oak.

3.3.2.2 Artificial regeneration

Artificial regeneration is the establishment of desired tree species by either direct seeding or the planting of seedlings or cuttings. Artificial regeneration requires a higher initial investment but can significantly increase control over species, genetics, density, distribution, and timing of regeneration.

Direct seeding is the manual or mechanical sowing of seeds. Stocking levels achieved are a result of the seeding rate and the amount and distribution of receptive seedbed. Direct seeding includes both broadcast (e.g. aerial) and precision (e.g. site prep mounted) seeding approaches. The biological requirements for direct seeding are more rigorous than for planting because both successful seed germination and seedling establishment are required. Successful direct seeding depends on proper site selection, adequate site preparation, and good seed distribution and quality. Seeding is most successful on sites where competition from other vegetation is minimal - competition problems become more likely when the time between harvesting, site preparation, and seeding is prolonged. Direct seeding offers some advantages over natural seeding including the option to pre-stratify, use improved seed, control timing and quantity, and achieve a more uniform distribution. Application methods include rotary and fixed-wing aircraft, site preparation mounted precision seeding, shelter cones, and hand sowing (e.g. acorns). Direct seeding has been used for many species in Ontario, but is most commonly used for jack pine and black spruce.

Planting is the establishment of regeneration by setting out seedling, transplants, or cuttings. Compared to other regeneration methods, planting can provide control over stand density and structure to achieve management objectives. However, it can also be the most costly and is a significant logistical undertaking. Planting is suitable for a wide range of sites and is often the regeneration option chosen for productive and competitive sites, whether site prepared or not. Substrate, site preparation method, stock type, stock handling, type of planting tool, weather, ability to tend, and other factors need to be considered carefully. A large variety of species are planted in Ontario but jack pine, white spruce, black spruce, white pine, red pine, and red oak are the most common.

3.4 Tending treatments

Tending is generally any operation carried out for the benefit of an already established forest crop at any stage of its life including cleaning, juvenile spacing, compositional treatments, improvement cutting, thinning, and pruning. Figure 3j indicates the timing of application for common tending treatments applied in Ontario.

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There is some overlap in the definition of different tending treatments and the treatment applied to any given site may serve more than one purpose. For example, manual tending between the establishment and stem exclusion stages may include removal of brush (cleaning), removal of undesirable trees (compositional treatment), and spacing of crop trees (juvenile spacing) all in a single treatment. The following text provides a definition and discussion of cleaning, juvenile spacing, compositional treatments, improvement cutting, thinning, and pruning.

3.4.1 Cleaning

Cleaning is a treatment conducted to release a regenerated stand from competing vegetation, including undesired tree species, that allows crop trees to establish dominance of the site. Removal or suppression of competing non-crop vegetation speeds stand development toward a future forest of the desired composition, structure, and growth rate (Wagner et al. 2001).

The type and timing of disturbance, pre-harvest stand condition, site characteristics, and autecology of competitor species all interact to influence post-harvest abundance of competing vegetation. Vegetation does not always have a level of impact on crop tree survival or growth that warrants an investment in cleaning; some vegetative cover may be desirable to protect conifers during establishment or to ‘train’ crop trees. Cleaning treatments must consider the tolerance of crop trees relative to the presence and abundance of vegetation, its impact on crop tree survival and growth, and the optimum timing for release.

Every tree species has a competition threshold defined as the level of vegetation abundance where there is an abrupt increase or decrease in the rate-of-change in tree growth or survival (e.g. Wagner et al. 1989). In addition, there is a critical period during which cleaning must occur to prevent loss and ensure the ability of the suppressed tree to recover.

A variety of methods are available to remove or suppress non-crop vegetation including chemical, manual, and mechanical cleaning.

Chemical cleaning is the use of herbicides to control non-crop vegetation. Generally speaking this is the most effective and least expensive means of providing longer term control of non-crop vegetation (Wagner et al. 2001). Herbicides can be applied through aerial spraying or through on-ground treatments using vehicle mounted equipment, backpack sprayers, or other hand application tools (wicks, injectors, etc.).

Manual cleaning is the manual cutting with motorized or non-motorized tools (e.g. motorized brush saws, chainsaws, and axes), girdling, clearing or scalping with hoes, and hand pulling, trampling, or binding of unwanted vegetation. Manual and motor manual cleaning are especially suited to harvest methods that leave an overstory canopy but can be costly, labour intensive, and involve greater risks to operator safety than most other cleaning methods.

Mechanical cleaning is the use of self-propelled, wheeled, or tracked prime movers with motorized cutting attachments to remove woody vegetation. Mechanical cutting, like manual cutting, is most effective in midsummer to reduce re-sprouting.

3.4.2 Compositional, spacing, and improvement cuts

A number of treatments can be applied after initial establishment to manipulate the density, composition, structure, and quality of the future stand to meet current or future management objectives. These treatments may be applied as part of a planned schedule (e.g. aerial seeding with planned spacing) or opportunistically as the sites respond to previous treatments and natural dynamics are expressed.

Juvenile spacing is the spacing of crop trees during the stand initiation stage. It is similar to pre- commercial thinning, except that it is carried out before canopy closure has occurred. At this stage of stand development, it may not be possible to select for dominance if it has not yet been expressed.

Compositional treatments alter the relative proportion of species to meet compositional objectives. Trees can be removed by cutting, girdling, or herbicide application. Stems that are removed may be merchantable or non-merchantable. One or more species may be targeted for removal in order to shift from one composition type to another. This may include removal of an undesirable overstory to release an established mid or understory.

Improvement cuts remove defective, undesirable, and overmature trees of any species to favour future stand development including release of regeneration, poles, and suppressed crop trees. Commonly applied in forest types managed through shelterwood and selection to manipulate structure between harvest entries or to remove additional stems that would not normally be removed during harvest. This may include removal of merchantable stems in stands not scheduled for a regular harvest.

3.4.3 Thinning

Thinning is a form of partial canopy removal in an established stand that concentrates potential wood production of a stand on selected trees (Smith et al 1997). Secondary objectives may include compositional objectives or developing future seed producing crowns. Thinning may be used to influence wood quality and quantity and achieve specific management objectives (habitat, aesthetics, watershed management, etc.).

Thinning practices may be either selective or systematic. Selective thinning refers to the removal or retention of trees based on their individual merits. Systematic thinning removes trees according to a predetermined system that does not permit consideration of the merits of individual trees. Thinning practices are further distinguished as commercial or pre-commercial based on the size of trees being removed and FMPM categorization of harvest versus tending treatments.

Timing of initial thinning operations varies by species, site quality, spacing, thinning intensity, harvesting and marketing conditions, and site level objectives. Density management diagrams allow resource managers to forecast required thinning time-frames based on initial spacing and site quality (e.g. site index). Timing and removal rates are normally based on the age at which stands intersect the zone of imminent competition and mortality. This represents the optimum point at which to thin the stand to maintain maximum stand-level diameter growth while reducing the chance of competition induced mortality. Appendix 4, based largely on the work of McKinnon et al (2006) and Kayahara et al (2006), describes a number of best practices and factors to consider when planning and undertaking a commercial thinning operation.

3.4.4 Pruning

Pruning is the removal of lower branches from standing live trees by natural or artificial means (NRC 1995). It is generally done when the desired end product is high value knot free logs (e.g. veneer logs) or to reduce the relative humidity within a stand to reduce the incidence of disease (e.g. white pine blister rust). Pruning can also be done to improve aesthetics and interior access to a stand. Pruning is not a common practice on crown lands in Ontario.

3.5 Amelioration

Amelioration is any operation carried out on the physical site to change one or more abiotic factors in order to improve the growth or quality of a stand. Typically this would include fertilization and/or drainage improvements. Neither drainage nor fertilization were considered as part of the Class Environmental Assessment (MOEE 1994) and therefore are not permitted as part of normal forest management activities on Crown land in Ontario. The suitability or limitations of these treatments have not been assessed in this guide. Managers who would like to undertake an amelioration treatment will need to follow the appropriate environmental assessment process to gain approval or exemption prior to undertaking any planned amelioration treatments.

3.6 Pre-harvest Treatments

The treatments discussed in sections 3.3 and 3.4 are normally applied following a harvest entry, however, many of them could be applied before harvest (e.g. prescribed fire) to manipulate post- harvest conditions (e.g. mid-story competition). Specifically, the suitability of pre-harvest herbicide, prescribed fire, site preparation, and planting are assessed in this guide (see management interpretation tables in section 5).

4.0 Planning and implementation

This guide is used to help plan and implement silviculture operations to achieve forest management objectives. The planning phase includes setting a management objective, identifying treatments that will achieve that objective, determining how often each of those combinations should be applied to create the kind of forest we want in the future, and developing performance standards to measure success. The implementation phase includes confirming ground conditions, stratifying the block into treatment units, committing to a future condition (e.g. forest unit and intensity) that matches the objective, identifying the likely combination of treatments required to get there, and monitoring performance.

The Forest Management Planning Manual (FMPM) provides details on the process and documentation requirements associated with each of these steps. The following sections are intended to complement the information in the planning manual and in no way replace or supersede that direction.

4.1 Planning

4.1.1 Developing silviculture ground rules

A silviculture ground rule identifies the current forest condition, silviculture system, future forest condition (i.e. at maturity), development information, management standards, regeneration standards, and acceptable alternative harvest, renewal and tending treatments for a specific forest condition. A number of silviculture ground rules are developed to cover the range of objectives specified in the long-term management direction.

The forest condition in a silviculture ground rule is typically expressed in terms of forest unit and site conditions. Forest units are aggregations of forest stands with similar composition, that develop in a similar manner both naturally and in response to treatment, and to which a single silviculture system can be applied. They are the primary classification for assumptions regarding how the forest develops through time.

The following steps approximate the process to apply the information and management interpretations in this guide while developing silviculture ground rules. In practice this process may be iterative, with information at one stage leading to a modification of what was set in a previous stage (e.g. forest unit definitions). Further, forest management plans normally have a good foundation to work from, including silviculture ground rules, in the previous plan. It may be more efficient to review existing ground rules for compatibility with the management interpretations in this guide than starting from scratch.

Step 1: Identify the future forest conditions that are likely to be targeted on your forest including species composition (primary, secondary, and incidental species) and age structure. Group these into similar conditions based on the forest unit definitions, yield curves, or other criteria (intensity, habitat objectives, etc.) developed for your FMP.

Step 2: Review the management interpretation tables from Section 5 that correspond to the species and conditions identified in step 1. Eliminate any silviculture systems, treatments, or combinations that are not possible and/or desirable on your forest. Pay particular attention to low probability and not recommended treatments and the associated rationale for that designation.

Step 3: For each future forest condition identified in step 1, identify treatment combinations (i.e. harvest, renewal, and tending) from step 2 that could be used to maintain or create each future condition.

Step 4: Evaluate the designation (i.e. high, low, not recommended – refer to section 5) for each system, method, or treatment identified in step 3. If a low probability or not recommended system, method, or treatment is included, confirm your ability/desire to undertake trial areas, exceptions monitoring, or make other adjustments (e.g. minimum rotation age) as applicable.

Step 5: Complete the appropriate silviculture ground rule documentation as outlined in the forest management planning manual.

4.1.2 Strategic silviculture options

Strategic silviculture options are used in strategic modeling to define assumptions about cost, success rates, and to limit model choices to reasonable and realistic treatments. The strategic silviculture options are groupings of silviculture ground rules that have the same current and future forest condition and are projected to develop on the same yield curve and successional trajectory.

The output of strategic modeling includes a schedule of how much of each strategic silviculture option (i.e. combinations of similar ground rules) is applied over time. The schedule is a combination of the options that were included (i.e. which ground rules), and balancing the achievement of multiple objectives. The schedule associated with the strategic direction becomes important context for selecting treatments at the site level.

4.1.3 Standards

Performance standards ensure results are consistent with assumptions made during development of the long-term management direction. They are set in advance of operations and provide an objective means of assessing the result of applying silviculture treatments. Performance standards vary by silviculture system and measure attributes such as the species, amount, size, and quality of regeneration and retained stems.

4.1.3.1 Regeneration standards

Regeneration standards provide a performance benchmark to determine if the results of silviculture activities were successful in meeting desired regeneration objectives, and can be used to make an early determination of whether a stand is tracking (or has the potential to track) towards a specified yield curve or desired future forest condition. Regeneration standards are normally applied to the clearcut and post regeneration stages of shelterwood systems with timing of measurement coordinated with anticipated development milestones in the stand. Formal assessment of regeneration standards (i.e. free-to-grow) typically occurs after all harvest and regeneration activities are complete and the trees have reached a size where they are free from vegetative competition. Information gathered in what is commonly referred to as ‘establishment surveys’ can be invaluable not just for the scheduling of tending and other supplementary treatments, but to effectively double the information available for silviculture effectiveness monitoring analysis (refer to section 6.2.1). Information from multiple surveys (i.e. establishment and FTG) facilitates investigation of cause and effect over shorter time periods and with fewer variables.

Free-to-grow monitoring compares the result of silviculture treatments to a regeneration standard. Regeneration standards are specific to a forest unit and silviculture intensity (see section 2.2.2) and set during the forest management planning process. The forest management planning manual describes the process and requirements for setting and documenting a regeneration standard. OMNR, 2009 provides a decision framework for developing regeneration standards. Additionally, OMNR, may choose to develop provincial standards, or a common framework for developing standards, that should be referenced as available. The following principles can help guide the development of a regeneration standard:

• have a high probability of developing onto the desired yield curve (consider: site occupancy, growth rate, regeneration delay, quality improvement, piece size, species composition, etc.)
• match to objective for the site including resolution/detail
• account for the influence of early stand dynamics

4.1.3.2 Performance standards in partial harvests

In partial harvests, where a mature canopy is retained (selection, commercial thinning, and shelterwood prep, regeneration, first removal) the choice and condition of retained trees has a direct influence on meeting objectives. Choices made during tree marking, block layout (landings, skid trails, etc.), harvest, renewal, and tending all contribute. In addition to developing a regeneration layer, performance standards in partial harvest areas measure:

• Improvement in Acceptable Growing Stock (AGS)
• Coverage/spacing of trees measured as basal area, crown closure, bole spacing or similar measures as defined in FMP.
• Extraction trail coverage
• Site damage

4.2 Selecting and implementing a silviculture ground rule

Silviculture ground rules provide information about what treatments can be applied to achieve the desired result on different sites. However, ground rules typically include multiple options to get to the same end, provide only summary level description of treatments, and there is normally more than one possible ground rule for any given site. Turning a ground rule into a site level prescription requires information about the site (specific soil, species, competition, constraints, etc.), context from strategic planning, incorporation of operational realities (available equipment, stock, etc.) and perhaps most importantly experience. Details not included in the silviculture ground rules like planting density, crown spacing, timing of tending, etc. must be determined for each treatment area.

The forest management planning process requires a ground rule be assigned to each stand as the harvest is planned. This is an initial estimate of treatments and results based on the available information at the time. The following steps provide an approximation of the process for selecting and implementing a silviculture ground rule after this initial planning step.

Step 1: Confirm site conditions. The timing of confirmation and level of detail should be matched to the complexity and information needs of possible prescriptions for the site. Information should be collected with enough resolution to capture any significant changes in conditions across the planned treatment area. The method (e.g. ground survey) used to confirm site conditions must provide a reasonable level of confidence that the selected prescription will be successful. Feedback from silviculture effectiveness monitoring may help prioritize site types and/or prescriptions where improved confidence is required.

Step 2: Using both the information collected in step 1, and the context provided by forest level objectives (e.g. increase white pine), commit to a future forest unit and intensity. This may require stratification of the site into multiple treatment units to account for differences in conditions (wet and dry areas, presence of advance regeneration, etc.), objectives, or available resources (e.g. planting stock). A myriad of operational realities must be considered including the silviculture system applied to the surrounding forest, ability to return for follow-up treatments, management constraints that may limit treatment options (e.g. protection of values), and many others.

Step 3: Using the eligible silviculture ground rules as a guide (i.e. consistent with future forest and intensity from step
2), select and schedule a combination of treatments that is appropriate for the specific conditions in the treatment unit, and consistent with achieving the desired future forest unit and assigned yield curve. A number of resources are available to help determine specific parameters for prescriptions (see Appendix 6).

Step 4: Apply treatments and monitor response to ensure stand is trending towards desired condition. Apply supplemental treatments as required. When the stand is not developing in the desired direction, and supplemental treatments are not practical or feasible, forecast the likely future condition that will be achieved and use that as additional context for treatment selection in step 2 for other sites. Document reasons for change in objective through Forest Operations Prescription (FOP) change layers or other relevant processes.

Step 5: At the appropriate development stage, report on stand condition with performance standards (regeneration standard, AGS improvement, etc.). Strive to understand the cause of both successes and failures. Use that information to refine future prescription setting and assumptions used in the next round of strategic planning.

In addition to the generic steps described above, decision keys have been developed for a number of the species addressed in this guide. The decision keys include suggested thresholds for choosing one treatment path over another based on site conditions, objectives, and operational realities. These can be found in appendix 5.

4.2.1 Pre-harvest assessment

The first step of the process above indicated the need to confirm on the ground conditions. This may include a formal and detailed pre-harvest assessment or less formal confirmation at the time of harvest. Less formal approaches to stand analysis may be appropriate where:

• Inventory is reliable and stand conditions are well-understood
• Management approaches are fairly consistent
• Levels of variability are anticipated and successfully dealt with as part of the normal fine tuning of prescriptions by well-trained forest workers at the time of operation.

Formal pre-harvest assessments of a greater intensity and resolution may be required in areas:

• Exhibiting variable level of tree quality, stocking, structure or species content
• Inventory accuracy is known to be low
• Where an error in judgment related to choice of silviculture system will have a significant impact on attainment of stand level objectives

A pre-harvest assessment can ensure that incorrect, missing or unique conditions found in an operating block are considered before operations commence. It provides an opportunity to not only verify attributes influential to silviculture success but to identify values (e.g. stick nests) and other features critical to implementation of integrated management principles (see section
2). A pre-harvest assessment of stand conditions may include:

• Species present including midstory and understory
• Stand stocking including variability, holes, and coverage by species
• Stand structure including age/diameter distribution, and canopy layers
• Individual tree quality, crown size, and canopy position
• Ecosite classification including soil texture, depth, and moisture regime
• Critical ecological features
• Confirmation of FOP

OMNR, 1996 includes further discussion and practical tools to assist with pre-harvest assessments and prescriptions development.

4.2.2 Role of site and ecosite in decision making.

Ecosite classification will allow identification of the long-term potential to achieve certain forest management objectives, and is thus an important component of the silviculture ground rules. Poor stand development and performance may be a reflection of unsuitable site conditions, which will impose limitations on potential value growth and justifiable investment level. Knowledge of a given ecosite with its characteristic mixture of species should provide the manager with the tools to consider which silviculture practices best emulate natural processes on that site. Figure 4a and 4b provide an overview of species-site compatibility by broad soil group (refer section 1.3) for conifer and broad-leafed species respectively. More detail on species-site compatibility is included Section 5.1 and appendix 2.

Figure 4a. Suggested species-site compatibility by broad soil group for selected conifer tree species [reproduced as an accessible table]

Figure 4b. Suggested species-site compatibility by broad soil group for selected broad-leafed tree species [reproduced as an accessible table]

The frequently encountered variable stocking, structure and quality characteristics of many second growth forests may be a function of historical events (such as high-grading, natural disturbance, or even lack of disturbance), rather than limitations of site or biological potential. Current forest condition influences what is possible and how much effort is required to achieve it, but site potential should not be ignored.

The common forestry lexicon includes the concept of “off-site” species. These are cases of a species growing on atypical and/or sub-optimal sites that would generally be described as ecologically inappropriate. While it is important to recognize the influence of historical events on current distribution of species, it is also important to recognize that some off-site associations may be natural, and reasonable to perpetuate, or recreate.

Somewhat opposite to “off-site” is the concept of prime site. To the extent feasible, tree species should be matched to sites that optimize their growth. This concept extends beyond stand level choices to overall landscape and road network designs. Within an overall ecosystem management approach that balances the achievement of other objectives, silviculture efforts should be focused on the areas that provide the highest economic return.

4.2.3 Prescription setting

The inherent variability of the natural world, combined with the myriad of possible management strategies and objectives to be applied on a given site, make it difficult to provide precise direction for setting a prescription. This guide will only speak to prescription setting briefly and in general terms.

It is important to note that this guide, particularly the management interpretation tables in section 5, do not contain sufficient detail to develop a prescription. The silviculturalist must apply their knowledge to determine the detailed parameters for planned treatments. For example, this guide may indicate that planting is recommended but does not provide advice on density, stock type, and other important parameters. To assist with the prescription development process suggested decision keys as well as example management approaches are presented for many species. In addition to the decision keys and example management approaches, suggested parameters and thresholds for some treatments are provided in the comment field of the management interpretations (see section 5.2).

4.2.4 Tree marking

Tree marking involves the careful selection of trees for harvest or retention based on tree size, vigor, timber quality, biodiversity, and wildlife habitat value. It is a valuable tool to ensure the harvest and regeneration prescription is accurately conveyed to all involved in the harvest and regeneration of the area. In complex stands and/or when complex prescriptions are applied, tree marking is a practical way of achieving desired outcomes.

The Forest Operations and Silviculture Manual provides direction on treemarking and treemarker certification^{footnote 9[9]}. Tree marking will normally include all applications of the selection silviculture system and the preparation, regeneration, and first removal stages of the shelterwood silviculture system (guideline). The forest management plan will specify which silviculture ground rules require tree marking (standard).

Tree marking is strongly encouraged for any harvest prescription where the complexity is difficult to convey directly to the forest worker. For example, when a clearcut with seedtree prescription is more complex than simply “leave all of species X”, tree marking will increase the probability of trees with the best seeding potential being left at an appropriate spacing. Other prescriptions, such as systematic row thinning, will certainly benefit from marking of rows to be removed, but do not necessarily require a certified tree marker to adequately convey the prescription.

It is important that the prescription indicates what the management objectives are in terms of the silviculture system to be employed, the quality of products considered, the implementation of measures concerned with non-timber values, and the long-term goals for the designated area. For Crown lands, information on forest level objectives and long term goals can be obtained from the approved Forest Management Plan. Armed with this information, a certified tree marker is expected to adapt the prescribed management approach, in an ecologically-appropriate manner, often while encountering unique forest conditions. Thus, the continuity of stand, and ultimately forest level objectives, are ensured.

4.2.5 Careful logging

In any logging operation there is the potential for causing unnecessary damage to the site, residual trees, and advance regeneration. While many factors (site, topography, weather, trail layout, machine type, etc.) influence the potential for damage, there is no substitute for a conscientious, well-trained, and experienced operator. A good operator in challenging conditions can produce a better result than a careless operator in ideal conditions.

While many of the strategies and techniques for minimizing the potential for or degree of damage are applied at the site (e.g. high floatation tires) and block (e.g. road, landing, and skid trail layout), there are some broader influences that need to be considered.

The direction (i.e. high, low, and not recommended) presented in the individual species level management interpretation tables (section 5.2) includes considerations for potential damage. In addition to the not recommended practices in section 5.2, the following direction on damage to residual stems will apply to shelterwood (excluding final removal), selection, and commercial thinning operations.

After harvesting, 90 % of the residual AGS (acceptable growing stock) basal area and 85 % of the total residual basal area will be free of major damage (standard).

Table 5a provides the definition of major damage. Damage below these thresholds (i.e. minor damage) can still have a significant impact on forest health, product quality, and stand level growth rates if abundant. While it is necessary to define major damage (table 5a) and articulate an allowable level for compliance purposes (i.e. 85/90), the goal should be as close to zero damage as possible. If operations are routinely coming close to exceeding damage thresholds the cause should be investigated and adjustments made.

Table 5a. Definition of major damage when applying logging damage standards

All aspects of an operation have the potential to influence the likelihood or directly cause damage. The influence of logging method in particular on advance regeneration, residual stems, and long-term nutrient budgets was carefully considered when developing the direction (i.e. high, low, and not recommended) in section 5.2. The Background and Rationale document that accompanies this guide provides a more fulsome description of the information used to make these determinations.

A substantial portion of the information was produced from exceptions monitoring and targeted research programs related to Not Recommended treatments in previous silviculture guides (see section 1.5.3 for list of previous guides). These include the results of exceptions monitoring efforts on fulltree logging and residual stem damage in shelterwood harvests (Jones and McPherson, 2012) and research and monitoring of fulltree logging on shallow soils (e.g. Ponder et al, 2012 ).

5.0 Management interpretations

The management interpretations in this section provide information about silviculture systems, methods, and treatments that may be used to achieve a future forest condition. The bulk of the interpretations are presented by individual species in section 5.1 with some additional considerations when targeting more than one species including in section 5.2.

5.1 Individual species

With the exception of the lowland hardwood and other hardwood groups, the management interpretations in this section are presented by individual species. The interpretations are presented at a broad level providing bounds on the overall silviculture approach (i.e. eligible treatments) and do not provide many of the details required to develop a site level prescription.

The management interpretation tables in sections 5.1.1 to 5.1.25 are guidelines and use specific terminology to categorize each treatment as high or low probability of producing results consistent with objectives or not recommended.

High probability: A treatment, method, or system that is likely^{footnote 10[10]}to produce results consistent with objectives based on best available evidence. High probability treatments may include conditions that have to be met for the treatment to have a high probability of success. Conditions may be related to; the type of sites that support a high probability of meeting objectives, associated treatments required to ensure high probability of meeting objectives, or a narrowed range of objectives where the probability is high. If condition(s) are not met, the treatment, method, or system is deemed low probability.

Low probability: A treatment, method, or system that may produce results consistent with objectives but the degree of uncertainty is too great to consider it a high probability. All low probability treatments, methods, or systems include a condition that they occur as part of a trial area (see section 6.2.3). When this condition cannot be met the treatment, method, or system is deemed not recommended.

Not recommended: A treatment, method, or system that is unlikely to produce results consistent with objectives.

Figure 5a provides a graphic portrayal of the planning requirements for high probability, low probability, and not recommended treatments, methods, or systems as well as species not included in the guide.

• How is the treatment, method, or system categorized in the management interpretation tables in section 5?
  • High probability
    • Are there any conditions associated with the high probability designation?
      • No
        • Proceed with regular planning of silvicultural activities as described in FMPM
      • Yes
        • Will the conditions be met?
          • Yes
            • Proceed with regular planning of silvicultural activities as described in FMPM
          • No
            • Plan as low probability
  • Low probability
    • Will the treatment, method, or system be included as part of a trial area?
      • Yes
        • Refer to section 6.2.2 for trial area requirements
      • No
        • Plan as not recommended
  • Not recommended
    • Refer to FMPM for exceptions monitoring requirements
  • Not included
    • Species not addressed in section 5
      • Follow regular planning using the best available knowledge and most current science

The determination of which systems, methods, and treatments were consistent with a specific future forest objective was based on the best available information including experiential and empirical information. For many species this included the development of a Bayesian Belief Network (BBN) to portray what variables (e.g. soil, water, and light) are influential, how management interventions might influence those variables, and what information is available to support that view. The background and rationale document (in prep) that accompanies this guide presents the BBNs for most of the species considered in this section. Included in the documentation are a number of literature citations that the practitioner may find useful to better understand why a particular treatment was recommended or not and to derive specific implementation parameters (e.g. what number of seed trees should I leave).

Some of the conditions in the management interpretation tables include limitations on the target density of the future forest. The target density classes used in the tables are high, moderate, and low. The specific values associated with these classes vary from one species to the other. Conceptually; high is a density where the species is expected to dominate the future composition and significantly influence the environment of the future stand; moderate is a density where the species is expected to be a significant but non-dominant component of the future stand; low is a density where the species may occur as scattered individuals, or small concentrations. For example, experience and/or ecological literature may indicate that clearcut with seedtree is not consistent with high regeneration densities of a particular species. In that case the condition would indicate clearcut with seedtrees is high probability only when targeting low to moderate densities. In this example, clearcut with seedtrees could only be used for high density objectives if part of a trial area or through formal exceptions monitoring (see section 6.2.3).

Layout of the individual species direction in sections 5.2.1 through 5.2.25.

The order of presentation is broad-leafed followed by conifer with alphabetical sorting by genus within each group.

The information and direction for each species is comprised of up to five components, each serving a slightly different purpose. The first four are included in this section - the fifth is included as an appendix.

1. A general discussion meant to provide an easy to read introduction for that species including keys to success, cautions to avoid, and recommended reading.
2. A management interpretation table categorizing each system, treatment or method as high or low probability of producing results consistent with objectives or not recommended. This includes a listing of any conditions that may apply as well as brief comments that may; explain a low probability or not recommended designation, highlight cautions, or list critical assumptions for implementation of high probability treatments.
3. Suggested management approach(es) including considerations for site selection, suggested implementation parameters, and how to choose between them.
4. A suggested decision key to assist the practitioner with selecting a management approach and choosing implementation parameters specific to the site conditions encountered while considering operational realities. For species that are typically managed as encountered and rarely drive the block-level approach, a decision key has not been developed.
5. Appendix 3 provides further information in a factsheet format on distribution, habitat, reproduction, growth, damaging agents, genetics, tolerances and response to disturbance. The factsheets are intended as a quick reminder, or reference on the silvics of less familiar species, when planning and carrying out forest management activities.

The management interpretation tables are guidelines (as noted above). The example management approaches and suggested decision keys are best management practices. The general discussion and factsheets are information items.

It is important to note that conditions within a harvest block (species composition, quality, post-harvest competition, moisture, etc.) can be quite variable and may require stratification into separate treatment units of feasible size and location. This may require sub-optimal treatment of some areas based on a pragmatic approach to the whole. The decision keys and example management approaches in particular need to be applied with this in mind.

For several species, a condition to “apply principles from the treemarking guide” is included for partial harvest silviculture systems. This is referring to the general principles outlined in the Tree Marking guide, particularly in Section 6. This would include principles like thinning from below, choosing cutting cycles and removal rates based on expected growth rates, marking for quality and stand structure improvement, placement of group openings, crop tree selection criteria, spacing guidelines, and so on. As stated in section 1.5.2, where direction in this guide overlaps with direction included in the tree marking guide (OMNR 2004), this guide takes precedence.

5.1.1 Red maple

Red maple (Acer rubrum) is tolerant of shade and can thrive on a wider variety of sites than any other hardwood species in Ontario. It has relatively low resource requirements, can tolerate dry ridges and saturated swamps, but exhibits best growth on moist loams. Regeneration occurs from seed, stump, and seedling sprouts. Seedlings tend to cycle quickly (i.e. establish, stagnate, die, repeat) under a full canopy but replacement rates are normally sufficient to capture the site when release occurs. Stump sprouts are often of poor form or high rot, particularly from larger diameter stumps. Seedling sprouts can be very successful, particularly if timed with a release event (e.g. harvest). Root form tends to adapt to soil conditions encountered with more lateral roots on high water table sites and deeper tap roots on drier sites. Red maple is predominantly managed through the shelterwood silviculture system, occasionally selection, but also well suited to open conditions following a clearcut.

Keys to success:

• Apply tree marking principles.
• Avoid very dry and very shallow sites.
• Maintain some overhead shade during early regeneration phase to provide a competitive advantage over less tolerant competition.

Cautions:

• Maple regeneration can be very aggressive and will likely require tending if other species are desired on the same site.
• The often lamented “red maple creep” – increased occurrence and dominance over large areas of central and southern Ontario that were previously logged or otherwise disturbed – may be further encouraged by some harvesting and regeneration practices. The landscape effect of harvest and regeneration decisions on red maple populations should be carefully considered.

Recommended reading:

• The red maple paradox. (Abrams 1989)

Target species: Red maple

Suggested management approaches – Red Maple

Note: Although quite prolific under a number of different management approaches, red maple is rarely targeted for regeneration and more commonly inhibits management and regeneration of other species.

Option 1 – Uniform shelterwood: Objective is the regeneration of an even-aged red maple dominated stand.

• Normally applied to tolerant hardwood stands with a minimum component of sugar maple (≥30%) combined with other species adapted to even-aged management (Pw, Sw, Or, Ow, Bd, Hi, Aw, Cb, By) and generally less than 50% poplar-birch or less than 30% hemlock or beech.
• Applied on poorer quality tolerant hardwood sites (i.e. not fresh silts and loams), or on good quality sites with low overstory quality (i.e. AGS < 9m²/Ha (or < 7m²/Ha AGS in sawlog sizes))
• Typically two cuts (regeneration and one removal cut) will be scheduled over a period of 5 to 15 years. When adequate density of advanced regeneration of desirable species (minimum 1 m tall) is present pre-harvest, consider moving straight to a final removal cut.

Regeneration cut

• Harvest from below to retain 50% to 70% crown closure (this would usually equate to a basal area in the range of 14 to 18 m²/Ha) removing UGS trees and undesirable seed sources. Heavier cuts will promote intolerant competition, a particular problem if little advanced regeneration is present.
• Trees to favor for retention in the regeneration cut are dominant - codominant crop trees with vigorous seed-producing crowns. Where no dominant trees are available, spacing and seed source can be provided by intermediate trees of desirable species. Seed is rarely limiting in maple stands with abundant seed occurring regularly. Retention of suitable crop trees of desired mid-tolerant species can increase species diversity of the new stand.
• Heavy mid-story of undesirable species (e.g. ironwood) should be removed to meet overstory canopy closure objectives.
• On sites with high competition (e.g. raspberry) the regeneration period may be delayed by up to 10 years as the maple establishes and grows to a competitive position.
• Site preparation is not normally required for maple as the large root radical can penetrate most litter layers.
• When stump sprouts comprise a significant portion of the regeneration on site, the sprouts should be evaluated for long-term viability. Sprouts originating high on the stump, or from large stumps, are more prone to rot and decline.

Final Removal

• When regeneration has reached a minimum of 1 m with an acceptable density, remove the remaining overstory. Delayed first removal will increase damage during harvest and risk suppression of regeneration as canopy fills in.
• When regeneration fails to establish, or is dominated by undesirable species (ironwood, elm, white birch, etc.) the decision to undertake remedial treatments, wait for the stand to develop further, or proceed with final removal will have to be tailored to the site and circumstances. Generalized advice cannot be provided here.
• Careful logging to protect the regeneration is critical. Minimize the number and width of skid trails. Where feasible, scheduling a removal cut when the ground is frozen and covered with snow (ideally 30 cm+) will reduce permanent damage to regeneration.
• Some regeneration ingress following final removal will occur on some sites but should not be counted on to achieve desirable densities.

Option 2 – Clearcut: Objective is the regeneration of even-aged red maple mixed with intolerants.

• Normally applied to stands with very poor stem quality, on sites with little quality potential, and presence of intolerants (e.g. aspen). Presence of maple advance regeneration, combined with careful logging practices, will greatly increase likelihood of a future maple component.
• Harvest all stems (excepting those required for diversity targets) to create open light conditions. Harvesting in summer (i.e. leaf on) will reduce the number and vigor of aspen sprouts in the first growing season. Harvesting in winter will increase survival of maple advance regeneration
• When maple advance regeneration is not present in sufficient quantity, retain 10 to 30 seed trees per hectare.
• Low lying sites should be harvested only when frozen or very dry (see comments for lowland hardwoods). Site disturbance can lead to a prolonged grass (e.g. calamagrostis) or brush dominated condition.

5.1.2 Sugar maple

Sugar maple (Acer saccharum) is very tolerant of shade, can have an even, multi, or uneven aged structure, and can tolerate a wide range of sites. Best growth is on well drained loams, it grows poorly on dry shallow soils, and is rarely found in swamps. Regeneration is primarily from seed and stump sprouts, occasionally from layering, rarely from root suckers, with seed being the most common. Germination and establishment can occur on a wide range of seed beds from leaf litter to mineral soil. Sugar maple typically produces an extensive seedling bank and clipped or broken seedlings readily re-sprout to pre-damage height. In open growing conditions established grass and herbaceous competition can impede establishment and growth. Sugar maple can tolerate low light at all stages of development and responds very well to eventual release. Concentrations of maple are typically managed through shelterwood or selection systems, but good growth can occur in clearcuts, particularly when advance regeneration is present.

Keys to success:

• Apply tree marking principles
• Avoid dry, shallow, and saturated sites.
• Maintain some overhead shade during early regeneration phase to provide a competitive advantage over less tolerant competition.

Cautions:

• Excessive opening can cause epicormic branching and crown dieback.
• Maple regeneration can be very aggressive and will likely require tending if other species are desired on the same site.

Target species: Sugar maple

Suggested management approaches – sugar maple

Typical management approaches when sugar maple is present in the pre-harvest stand and selected as the management objective.

Option 1 – Single tree Sslection: Objective is the maintenance and improvement of an un-even aged stand of sugar maple - beech - hemlock.

• Normally applied to tolerant hardwood stands with a pre-harvest BA ≥ 24 m²/ha (varies by region), AGS ≥ 9 m²/Ha (or ≥ 7 m²/ha AGS in sawlog sized trees), an uneven aged-structure, and growing on deep, fresh silty sands and coarse loams.
• Marginal stands not quite meeting the above criteria may be successfully managed under the selection system but will likely require modifications such as lighter harvest in the initial cuts, a longer interval between cuts to compensate for slower growth rates of low quality trees (up to 35 years), and more cutting cycles to achieve desired quality/structure. These stands may be better suited to the shelterwood system.
• May also be applied to even aged stands on good sites which will develop into an un- even aged structure over time through harvest and improvement treatments.
• Harvest up to 1/3 of the basal area to a minimum retention of 18-22 m²/ha (varies by initial stand quality, stocking, site and region) (Leak et al. (1969), Marquis et al. (1992), and Nyland, (1987)). Harvest and retention decisions need to consider vigor and risk, stand structure targets (i.e. BA by size class), AGS improvement targets, species priority, and diversity objectives. Refer to the Ontario Tree Marking Guide (OMNR 2004) for further elaboration.
• Apply careful logging principles at all steps of the operation to minimize damage to the site, residual stems, and desirable advanced regeneration.
• Stand improvement to remove highly competitive, lower value mid-story species (e.g. iron wood, red maple, balsam fir, etc.) and unmerchantable UGS stems of the target species is recommended either at time of harvest or with follow up treatments.

Option 2 – Group selection: Objective is the maintenance and improvement of an un- even aged stand composed of sugar maple and other shade tolerants with a mid-tolerant species component.

• Incorporate group openings as part of regular selection management throughout the rest of the stand as described in option 1 to promote regeneration of mid-tolerant species within a stand dominated by sugar maple (e.g. red oak, yellow birch, basswood, white ash, black cherry, and white pine).
• Create groups in areas of higher UGS adjacent to mid-tolerant species seed trees, with particular regard for any areas of mid-tolerant advanced regeneration.
• Avoid locating groups in areas of smaller diameter AGS crop trees.
• Refer to example management approaches for other species for specific guidelines for group location, size, and renewal treatments.
• Number and arrangement of group openings should capture the best mid-tolerant regeneration opportunities and may range from 5% to 20% of total area, depending upon cutting cycle, regeneration objectives, and stand quality. The total volume cut should not exceed stand growth over a cutting cycle.
• In group openings and the immediately surrounding forest (within 10 to 20 m, particularly on the north side of the opening), all trees 2.5 cm dbh and larger should be cut or removed by planned skidding disturbance or scarification. Selective removal of non-crop tree species under 2.5 cm will also be of benefit to regeneration.
• Assess regeneration of target species and consider planting or scarification where densities are low, competition is manageable and suitable nursery stock is available. Vigorous seedlings with a well-developed root system should be planted within operability constraints.
• Apply timely control of competition around regenerating stems (especially during first 5 years).
• In subsequent cuts careful logging to protect the regeneration is critical. If mid tolerant hardwoods have regenerated in the openings, the periphery of the openings may need to be expanded to release establishing regeneration.

Option 3 – Uniform shelterwood: Objective is the regeneration of an even-aged sugar maple dominated stand.

• Normally applied to tolerant hardwood stands with a minimum component of sugar maple (≥30%) combined with other species adapted to even-aged management (Pw, Sw, Or, Ow, Bd, Hi, Aw, Cb, By) and generally less than 50% poplar-birch or less than 30% hemlock or beech.
• Applied on poorer quality tolerant hardwood sites, or on good quality sites with low overstory quality (i.e. AGS < 9 m²/ha (or < 7 m²/ha AGS in sawlog sizes))
• Typically two harvest cuts (regeneration and one removal cut) will be scheduled over a period of 5 to 15 years. When adequate density of advanced regeneration of desirable species (minimum 1 m tall) is present, consider moving straight to a final removal cut.
• Forest managers may choose to employ a first removal (release) cut in some situations, especially to promote the development of smaller sized trees.

Regeneration cut

• Harvest from below to retain 50% to 60% crown closure (this would usually equate to a basal area in the range of 14 to 16 m²/Ha) removing UGS trees and undesirable seed sources. Heavier cuts will favor intolerant and/or mid tolerant hardwood regeneration if advanced maple regeneration is not plentiful.
• Trees to favor for retention in the regeneration cut are dominant - codominant crop trees with vigorous seed-producing crowns. Where no dominant trees of desirable species are available, spacing and seed source can be provided by intermediate trees.
• Seed is rarely limiting in maple stands with abundant seed occurring regularly.

Retention of suitable crop trees of desired mid-tolerant species can increase species diversity of the new stand.

• Heavy mid-story of highly competitive, lower value species (e.g. ironwood) should be removed to meet overstory canopy closure objectives.
• Generally when sugar maple establishment is successful it tends to be abundant.

Management should target >40% stocking with >12,500 sugar maple seedlings/ha (>5 stems in a 4m² plot) measuring >0.6 m in height, typically 5-7 years after harvest (Leak et al. (1987), Jacobs (1974), Tubbs (1977)). This should result in >2500 stems per ha measuring 5-10 cm at dbh at the late sapling stage of development (Tubbs, 1977).

• On sites with high competition (e.g. raspberry) the regeneration period may be delayed by up to 10 years as the maple establishes and grows to a competitive position.
• Site preparation is not normally required for maple as the large root radical can penetrate most litter layers and may in fact reduce regeneration potential.

Final removal

• When regeneration has reached a minimum of 1 m with an acceptable density, remove the remaining overstory (Tubbs, 1977a). Delayed first removal will increase damage during harvest and risk suppression of regeneration as canopy fills in.
• Retain residual trees for wildlife habitat (e.g. trees with cavities) and ecological reasons (e.g. veteran trees) as prescribed in Stand and Site Guide and groups of AGS polewood of desired crop tree species.
• Careful logging to protect the regeneration is critical. Minimize the number and width of extraction trails. Where feasible, scheduling a removal cut when the ground is frozen and covered with snow (ideally 30 cm+) will reduce permanent damage to regeneration.
• Some regeneration ingress following final removal will occur on some sites but should not be counted on to achieve desired densities.

Option 4 – Two-aged stands: Depending upon the species composition, the long-term objective may be the development of an even-aged or an uneven-aged tolerant hardwood stand.

• Two-aged stands have typically developed from a previous high-grade harvest.

The overstory of these stands consists of low quality intolerant, mid-tolerant and tolerant hardwoods, pine and/ or spruce. The understory is variable quality, moderately stocked (typically 6 to 15 m²/ha, 60%+ of which should be AGS) polewood and small log sized tolerant/mid-tolerant hardwoods, white pine, and/ or hemlock. Understory stocking may be uniform or patchy.

• There is a high degree of variability in these stands and the objective is to increase the percentage of AGS and uniformity of the stand while promoting the growth of the future crop trees. The principles to be applied in their management are:
  • A portion of the overstory should be removed and the understory AGS trees released.
  • Overall basal area removal of UGS stems is typically between 35% and 45% of initial stocking, depending upon stand density and quality, stocking and distribution of crop trees, and intolerant hardwood component. The combined residual crown closure of both strata will be between 50 and 70%.
  • Retain higher residual basal area or crown closure when the objective is the development of an uneven-aged stand of sugar maple, beech, and hemlock. Lower residual stocking levels are used when the objective is an even-aged stand with a higher component of mid-tolerant species.
  • On better sites, crop tree thinning of mid-tolerants in the understory is important to promote crown development.
  • Crop trees to be released should not be suppressed and flat topped. Target 150 to 250 crop trees per ha, depending upon age and diameter (Miller et al.(2007), OMNR, (2000)).
  • Overstory UGS trees which are overtopping patches of understory crop trees should be removed.
  • The retention of minimum stocking levels (i.e. 12 to 16 m²/ha) to avoid excessive release of AGS crop trees in the understory is important for quality development in the residual stand. This will typically require the retention of some UGS stems.
  • AGS mid-tolerant hardwood, pine, hemlock and/or spruce seed trees should be retained at a regular spacing to provide opportunities for regeneration of these species.
  • Consider manual or selective chemical tending for timely control of competition around established seedlings.

Option 5 – Clearcut with seed trees: Objective is renewal of an even-aged intolerant hardwood forest with a minor sugar maple component

• Normally applied to stands dominated by intolerant hardwoods (poplar, white birch) with a minor component of sugar maple plus other common associates adapted to even-aged management (Pw, Pr, Sw, Or, Ow, Bd, Hi, By, Aw, Cb). Typically in this situation the combined basal area of sugar maple and all other compatible species is < 8 m²/Ha in sawlog-size classes or < 10 m²/ha in all size classes. Limit application in settled landscapes with low forest cover.
• May also be applied in stands with a higher sugar maple component where a large majority of sugar maple and associated species are exhibiting severe decline/mortality.
• Retain 15 to 35 healthy sugar maple and other seed trees per hectare as available at spacing of 15 to 25 meters.

Suggested decision key when determining the appropriate management approach for sugar maple (assumes maple is desired and present in pre-harvest stand).

• Can the site support good maple quality (e.g. deep,fresh to moist, loamy to fine soils)
  • No: Consider alternative species
  • Yes: Future age structure objective
    • Even
      • Is the stand severely degraded or dominated by intolerants?
        • Yes: Clearcut with seedtree
        • No: Uniform shelterwood
    • Uneven
      • Overstory primarily tolerant hardwoods?
        • No: Consider switching to even-aged
          • Go to “Is the stand severely degraded or dominated by intolerants?”
        • Yes: BA of acceptable growing stock
          • <9: Go to “Consider switching to even-aged”
          • ≥9 (≥7 sawlog): BA of tolerant hardwood and compatible species?
            • ≥24: Is the majority of the BA in a single size class?
              • No: Are mid-tolerants present and desired in future stand?
                • Yes: Group selection
                • No: Single tree selection
              • Yes: Can the stand be transitioned to un-even structure within a reasonable time frame?
                • Yes: Go to “Are mid-tolerants present and desired in future stand?”
                • No: Consider switching to even-aged
            • <24: Is Acceptable Growing Stock mainly in poles
              • No: Wait for BA to increase. Stand improvement and crop tree release as required.
              • Yes: Case by case decision. Presence of advance regen, poles well distributed, lack of structure in overstory, etc. may be better suited to final removal shelterwood
                • Go to “Is the majority of the BA in a single size class”
                • Go to “Uniform shelterwood”

5.1.3 Yellow birch

Yellow birch (Betula alleghaniensis) is mid-tolerant of shade, occurs in almost pure, even-aged fire-origin stands, mixed with other hardwoods on upland sites and with hemlock, cedar, and balsam fir around lakes. It regenerates primarily from seed although sprouts from smaller stumps are not unheard of. Mineral or mixed organic/mineral soil required for germination and small radical can be inhibited by even a thin layer of matted litter (e.g. maple). Best growth is on moist lower slopes with deep loamy soils and a telluric water table. Concentrations of yellow birch are typically managed through the shelterwood system with lower densities or isolated pockets managed through seedtree or group selection prescriptions.

Keys to success:

• Choose fresh to moist deep loamy sites from middle to toe of slope.
• Time seedbed preparation (e.g. scarification) with a good seed year (male catkins on twigs in winter signal a seedcrop the following fall/winter). Dispersed skidding may provide adequate seedbed preparation on some sites.
• Regenerate in partial shade followed by gradual release. Maintain adequate light throughout stand development through crop tree release and thinning.

Cautions:

• Site damage and aggressive seedbed preparation on rich sites can stimulate seedbank (e.g. raspberry) and other competitors.
• Epicormic branching and crown dieback can occur in excessively opened stands.
• High incidence of deer or hare may lead to significant loss of regeneration.
• Shallow plate-type roots can lead to windthrow, particularly on shallow or saturated soils.

Target species: Yellow birch

Suggested management approaches – yellow birch

Typical management approaches when yellow birch is present in the pre-harvest stand and selected as the management objective.

Option 1 – Uniform shelterwood (two cut): Objective is the renewal of an even-aged yellow birch dominated forest

• Normally applied to yellow birch stands with a minimum component of yellow birch (≥ 30%) and composition of yellow birch plus other common associates adapted to even-aged management (Pw, He, Sw, Sr, Or, Bd, Hi, Aw, Cb) of ≥ 50%. Basal area of yellow birch is typically at least 8 to 10 m²/Ha and overall stand basal area ≥ 22 m²/Ha. Shade tolerant hardwoods (Mh, Be) typically compose less than 50% of BA.
• Depending upon initial stand stocking, site quality, and competition two harvest cuts are planned: a regeneration cut followed by a single removal cut 7 to 10 years after the regeneration cut.
• Stands designated for yellow birch management require regular observations of regeneration, and timely renewal treatments (i.e. site preparation and tending) and final removal cut.
• Trees to favor for retention in shelterwood harvests are dominant-codominant crop trees with vigorous seed-producing crowns. Where no dominant-codominant trees of desired species are available, spacing and seed source can be provided by intermediate trees.
• Priority crop tree species to retain are yellow birch, white pine, hemlock, red/white spruce, red oak, hickory, white ash, black cherry.

Regeneration cut

• Retain 50% to 60% canopy closure post-harvest (this would usually equate to a basal area in the range of 12 to 16 m²/Ha) (Tubbs, 1977), favoring yellow birch seed trees for retention over other crop tree species.
• Heavy mid-story of undesirable tree species must be removed to meet overstory canopy closure objectives and provide adequate light for the growth of yellow birch regeneration. Heavy mid-story competition can eliminate yellow birch regeneration within a few years.
• Removal of leaf litter through prescribed burning, mechanical site preparation, or harvester or skidder activity is strongly recommended for establishment of new germinants – target 60% to 70% coverage of suitable seedbed (i.e. mineral soil, humus, well decayed logs/stumps).
• Timing of harvest and/or mechanical site preparation with a good seed year (about every three years) will increase probability of regeneration establishment. Good seed years can be predicted up to one year in advance by observing the development of male catkins.
• Prescribed burning and mechanical site preparation treatments should be planned for after leaf fall and before snow fall.
• Chemical site preparation to remove maple/beech seedling bank, and initial flush of seedbank (e.g. raspberry) will improve success. Chemical site preparation must occur prior to establishment of yellow birch germinants or seedlings to avoid mortality.
• Assess stocking and competitive position of yellow birch regeneration on a regular basis. Generally when yellow birch establishment is successful it tends to be abundant.
• Seedlings should attain a minimum height of 15 cm during their first year to prevent smothering or crushing by leaf fall (OMNR, 1983). Even so, significant mortality can be expected over the first 10 years.
• Management should target >40% stocking with >12,500 yellow birch seedlings/ha (>5 stems in a 4 m² plot) measuring >0.6 m in height, typically 5-7 years after harvest. (Leak et al. (1987), Jacobs (1974), Tubbs (1977)). This should result in >2500 stems per ha measuring 5-10 cm at dbh at the late sapling stage of development (Tubbs 1977).
• Consider manual or selective chemical tending for timely control of competition around established seedlings.

Final removal cut

• Schedule final removal harvest when saplings reach ~2 m and exceed minimum stocking levels. Delayed removal may increase damage during harvest, and the vigour and amount of yellow birch regeneration will decline over time in the increasing shade environment, making them less responsive upon later release. Earlier removal (1 to 2 m height) can occur if competition is adequately controlled.
• Retain residual trees for wildlife habitat (e.g trees with cavities) and ecological reasons (e.g veteran trees) as prescribed in Stand and Site Guide and groups of AGS polewood of desired crop tree species.
• Careful logging to protect the yellow birch regeneration is critical. Minimize the number and width of extraction trails. Where feasible, scheduling a removal cut when the ground is frozen and covered with snow (ideally 30 cm+) will reduce permanent damage to regeneration.
• Consider thinning or crop tree release treatments as the stand continues to develop.

Option 2 – Group selection: Objective is management of an all-aged tolerant hardwood forest with a yellow birch component

• Normally applied to stands with a lower component (<30%), or clumpy distribution, of yellow birch mixed with good quality tolerant hardwoods. May also be applied in settled landscapes with low forest cover.
• Groups are typically (but not always) applied in conjunction with a normal selection harvest throughout the rest of the stand.
• Create groups in areas of higher UGS adjacent to yellow birch seed trees, with particular regard for any areas of yellow birch advanced regeneration. Moist soils with moving water (i.e. side and toe slope positions) are preferred locations for groups. These are sometimes referred to as “telluric” water tables.
• Avoid locating groups in areas of smaller diameter AGS crop trees.
• Group size should be a minimum of 20 meters (or tree height) in diameter crown edge to crown edge (30 meters from bole edge to bole edge) with larger (30-40 meters crown edge to crown edge) sizes preferred when return harvest for group expansion will not occur prior to the next selection entry. For more information on group opening size for minor species see the section: Mid-Tolerant and Intolerant Hardwoods: Minor Species (section 5.2.5).
• Number and arrangement of openings should capture the best yellow birch regeneration opportunities and may range from 5% to 20% of total area, depending upon cutting cycle, regeneration objectives and stand quality. The total volume cut should not exceed stand growth over a cutting cycle.
• In group openings and the immediately surrounding forest (within 10 to 20 m, particularly on the north side of the opening), trees 2.5 cm dbh and larger should be cut or removed by planned skidding disturbance or scarification. Selective removal of non-crop tree species under 2.5 cm will also be of benefit to regeneration.
• Removal of leaf litter and understory competition through prescribed burning, mechanical site preparation, or skidding during harvest will greatly improve success of establishment of new germinants – target 60% to 70% coverage of suitable seedbed (i.e. mineral soil, humus, well decayed logs/stumps).
• Assess regeneration of target species and consider planting or scarification where densities are low, competition is manageable, and suitable nursery stock is available. Vigorous seedlings with a well-developed root system should be planted within operability constraints. Avoid planting of yellow birch in groups located within areas of high deer populations.
• Apply timely control of competition around regenerating stems (especially during first 5 years).
• In subsequent cuts careful logging to protect the yellow birch regeneration is critical. Where feasible, schedule group expansion to maintain similar light levels to those suggested for uniform shelterwood.

Option 3 – Two-aged stands: Depending upon the species composition, the long-term objective may be the development of an even-aged yellow birch stand or an uneven-aged tolerant hardwood stand with a yellow birch component.

• Two-aged stands have typically developed from a previous high-grade harvest. The overstory of these stands consists of low quality intolerant, mid-tolerant and tolerant hardwoods, pine and/ or spruce. The understory is variable quality, moderately stocked (typically 6 to 15 m²/Ha, 60%+ of which should be AGS) polewood and small log sized tolerant/mid-tolerant hardwoods, white pine, and/ or hemlock. Understory stocking may be uniform or patchy.
• There is a high degree of variability in these stands and the objective is to increase the percentage of AGS and uniformity of the stand while promoting the growth of the future crop trees. The principles to be applied in their management are:
  • A portion of the overstory should be removed and the understory AGS trees released.
  • Overall basal area removal of UGS stems is typically between 35% and 45% of initial stocking, depending upon stand density and quality, stocking and distribution of crop trees, and intolerant hardwood component. The combined residual crown closure of both strata will be between 50% and 70%.
  • Retain higher residual basal area or crown closure when the objective is the development of an uneven-aged stand of shade tolerant hardwoods with a yellow birch component. Lower residual stocking levels are used when the objective is an even-aged stand dominated by yellow birch.
  • On better sites, crop tree thinning of mid-tolerant trees in the understory is important to promote crown development.
  • Crop trees to be released should not be suppressed and flat topped. Crowns should be released on at least 3 sides. Target 150 to 250 crop trees per ha, depending upon age and diameter (Miller et al.(2007), OMNR, (2000)).
  • Overstory UGS trees which are overtopping patches of understory crop trees should be removed.
  • The retention of minimum stocking levels (i.e. 12 to 16 m²/ha) to avoid excessive release of AGS crop trees in the understory is important for quality development in the residual stand. This will typically require the retention of some UGS stems.
  • AGS mid-tolerant hardwood, pine, hemlock and/or spruce seed trees should be retained at a regular spacing to provide opportunities for regeneration of these species.
  • Consider manual or selective chemical tending for timely control of competition around established seedlings.

Option 4 – Clearcut with seed trees: Objective is renewal of an even-aged intolerant hardwood forest with a minor yellow birch component

• Normally applied to stands dominated by intolerant hardwoods (poplar, white birch) with a minor component of yellow birch plus other common associates adapted to even-aged management (Pw, Sw, Or, Bd, Aw, Cb). Typically, in this situation the combined basal area of yellow birch and all other compatible species is < 8 m²/Ha in sawlog-size classes or < 10 m²/ha in all size classes. Limit application in settled landscapes with low forest cover.
• May also be applied in stands with a higher yellow birch component where a large majority of yellow birch and associated species are exhibiting severe decline/mortality.
• Retain 15 to 35 healthy yellow birch and other seed trees per hectare as available at spacing of 15 to 25 meters
• Timing of harvest and/or mechanical site preparation with a good seed year (about every three years) will increase probability of success. Good seed years can be predicted up to one year in advance by observing the development of male catkins.
• Open growing conditions combined with presence of fast growing intolerant (e.g. white birch and poplars, plus raspberries and shrubs) and tolerant (e.g. maples) hardwood regeneration will require early and regular competition control to release yellow birch regeneration.

Option 5 – Clearcut, strip progressive 3 cut: Objective is renewal of an even-aged yellow birch forest

• Currently being used on a limited basis, an option considered in stands of the northern transitional forest where the site condition and quality of sugar maple suggests conversion to the better-adapted yellow birch (OMNR, 1998).
• For example, one SFL has applied this prescription in stands where current condition has a component of yellow birch in the overstory (By ≥ 10 m²/Ha), the development potential of producing high quality By sawlogs clearly exceeds that of Mh, and conditions are not suitable to harvest uniformly (shelterwood) across the site. The goal is to move stands toward the conditions of the By forest unit. Once there, these stands will be managed with uniform shelterwood principles (NFRM, 2009).
• Typically requires one more stand entry (3 cuts) than uniform shelterwood (2 cuts).
• Stands will require regular observations of regeneration, and timely renewal treatments.
• Strip width ranges from one to two tree heights (bole to bole). Each cut strip represents one third of total stand basal area.
• Release crowns of quality By/Or/Cb seed trees along perimeter of retained strips.
• Mineral soil exposure timed with a seed year is essential. If soil is not extensively disturbed during logging, follow-up site preparation will be required.
• Consider manual or selective chemical tending for timely control of competition around established seedlings.
• Implementation of the second and third strips is contingent on meeting the regeneration standard in the previously cut strips.
• Yellow birch seed trees are retained in the third strip.
• Retain residual trees for wildlife habitat (e.g. trees with cavities) and ecological reasons (e.g. veteran trees) as prescribed in Stand and Site Guide.

Suggested decision key when determining the appropriate management approach for yellow birch (assumes yellow birch is desired and present in pre-harvest stand).

• Fresh to moist deep loamy soils ideally with moving water (i.e. side and toe slope position)?
  • No: Consider regenerating to an alternative species
  • Yes: Predominantly intolerant hardwoods, and/or yellow birch in severe decline
    • Yes: Clearcut seedtree
    • No: By ≥30% and By+ compatible (Pw,He, Sw,Sr,Or,Bd,Hi,Aw,Cb) ≥50% of pre-harvest BA?
      • No: Suitable (species, BA, site, stand structure, etc.) for selection?
        • No: Clearcut seedtree
        • Yes: Group selection
      • Yes: Able to create ≥50% receptive seedbed (site prep, dispersed skidding, etc.)
        • Yes: Uniform shelterwood
        • No: Consider regenerating to an alternative species

5.1.4 White birch

White birch (Betula papyrifera) is shade intolerant, can regenerate from both stump sprouts and seed, with seed origin stems being of better quality. White birch can tolerate a wide range of sites including dry and coarse soils but grows significantly better on fresh loamy sites. Early regeneration can be very dense with rapid self-thinning. White birch is normally managed through the clearcut silviculture system with complete, or nearly complete, overstory removal. White birch exhibits a moderate shade tolerance when young allowing for management through the shelterwood system if the final removal occurs relatively quickly. Competition on rich sites can significantly reduce survival of young birch.

Keys to success:

• Full or nearly full sunlight is required to survive past seedling/sapling stage
• Retain adequate seed trees within the block (or adjacent). Trees stressed from harvest may die quickly (1-2 growing seasons) but often produce copious amounts of seed.
• Exposed mineral soil.

Cautions:

• Avoid sites prone to excessive drying during drought periods
• Mature white birch can exhibit significant dieback when retained in a clearcut
• White birch is sensitive to root system disturbance
• Supressed white birch has limited/no ability to respond to release

Recommended reading:

• Proceedings for the Ecology and Management of White birch Workshop. OMNR, (Chen et al. 2000).
• Paper birch Managers’ Handbook for British Columbia. B.C. Ministry of Forests.
  Forest Science Program. FRDA Report 271. (BCMOF, 1997)

Target species: White birch

Suggested management approach – White birch

Option 1 – Clearcut Natural (Seed): Objective is the renewal of an even-aged birch- dominated forest

• Normally applied to upland stands with a minimum white birch composition of 50%, and ideally above 70%, on a deep, dry to fresh, coarse loamy, soil.
• Limited suitability in late-successional birch stands that are showing visible signs of dieback. Limited suitability when aspen exceeds 20%, particularly if well distributed, as aspen will sucker prolifically and outcompete birch on most sites. Moderate pre- harvest densities of jack pine may lead to significant ingress of young jack pine.
• Harvest to provide a minimum of 70% full sunlight while retaining 20 to 30 (depending on crown size) well distributed white birch seed trees per hectare.
• Harvesting on frozen ground will minimize damage to root systems and reduce post- harvest crown dieback commonly displayed by white birch. Harvesting on dry unfrozen ground will improve available seedbed.
• Consider site preparation treatments if exposed seedbeds are lacking, ideally in late fall prior to a good seed year. On sites with moderate duff and slash, simple drags such as barrels and chains can be effective.
• Stump sprouts may also contribute to the future stand with younger (<60 years) stumps producing more frequently. Prescribed fire can further stimulate stump sprouting if done while birch is green (i.e. immediately after harvest).
• Allow three growing seasons prior to conducting a regeneration survey for seedling density, stocking, and survival. A high density of germinants does not guarantee a high density of seedlings as early mortality from competition and other factors can be very high.

5.1.5 American beech

American beech (Fagus grandifolia) is very shade tolerant, is typically a late successional species, and commonly associates with sugar maple. Best growth is on fresh loams with a high humus content, but also found on sandy to fine loamy and clayey soils. Regeneration is from both seed and stump sprouts with seed falling in the vicinity of the parent tree. Germination can occur on a variety of substrates including thin hardwood litter provided adequate moisture is maintained. Beech can tolerate shade at all stages of development, particularly in the seedling and sapling phase, and responds well to release. Beech is typically managed through the selection silviculture system but is also consistent with shelterwood and clearcut systems when provided an early competitive advantage. Beech bark disease presents significant challenges to management of beech in Ontario.

Keys to success:

• Apply tree marking principles
• Maintain some overhead shade during early regeneration phase to provide a competitive advantage over intolerant competition.
• Avoid very dry, shallow, nutrient poor, or saturated sites.

Cautions:

• Open growing conditions may cause excessive drying of the seedbed inhibiting germination and establishment
• Beech bark disease and the associated scale insect is currently found in parts of Ontario and expected to expand across the range of beech over time. This disease presents significant challenges for management of beech at stand and landscape scales. Managers should apprise themselves of the latest knowledge and recommendations before proceeding with a management approach.

Recommended reading:

• Beech Bark Disease in Ontario: A Primer and Management Recommendations. (McLaughlin and Greifenhagen, 2012)
• Biology and Management of Beech Bark Disease. Michigan State University
  Extension Bulletin E-2746. (McCullough et al. 2005)

Target species: American beech

Suggested management approaches – Beech

Conventional management approach when American beech is present in the pre-harvest stand and maintenance of a beech component is a management objective.

Option 1 – Single tree selection: Objective is the maintenance of a beech component in an un-even aged tolerant hardwood stand.

• Normally applied to shade tolerant hardwood stands with a pre-harvest BA ≥ 24 m²/Ha (varies by region), an uneven aged-structure and growing on deep, fresh silty sands and coarse loams.
• Stands not meeting the above criteria may be successfully managed under the selection system but will likely require modifications such as lighter harvest in the initial cuts, a longer interval between cuts to compensate for slower growth rates of low quality trees, and more cutting cycles to achieve desired quality/structure.
• Beech will regenerate from seed on undisturbed leaf litter and from root suckers in low to moderate light conditions and fresh soil moisture regimes.
• Harvest up to 1/3 of the basal area to a minimum retention of 18-22 m²/ha (varies by initial stand quality, stocking, site and region). Harvest and retention decisions need to consider vigor and risk, stand structure targets (i.e. BA by size class), species priority, and diversity objectives. Refer to the Ontario Tree Marking Guide for further elaboration.
• Apply careful logging principles at all steps of the operation to minimize damage to the site, residual stems, and desirable advanced regeneration.
• Stand improvement to remove highly competitive, lower value mid-story species is recommended (e.g. iron wood, striped maple, etc.) either at time of harvest or with follow up treatments.

Option 2 – Two-aged stands: The long-term objective may be the development of either an even-aged or uneven-aged tolerant hardwood stand with a beech component.

• Two-aged stands have typically developed from a previous high-grade harvest. The overstory of these stands consists of low quality intolerant, mid-tolerant and tolerant hardwoods, pine and/ or spruce. The understory is variable quality, moderately stocked (typically 6 to 15 m²/ha, 60%+ of which should be AGS) polewood and small log sized tolerant/mid-tolerant hardwoods, white pine, and/ or hemlock. Understory stocking may be uniform or patchy.
• There is a high degree of variability in these stands and the objective is to increase the percentage of AGS and uniformity of the stand while promoting the growth of the future crop trees. The principles to be applied in their management are:
  • A portion of the overstory should be removed and the understory AGS trees released.
  • Overall basal area removal of UGS stems is typically between 35% and 45% of initial stocking, depending upon stand density and quality, stocking and distribution of crop trees, and intolerant hardwood component. The combined residual crown closure of both strata will be between 50 and 70%.
  • Retain higher residual basal area or crown closure when the objective is the development of an uneven-aged tolerant hardwood stand. Lower residual stocking levels are used when the objective is an even-aged stand with a higher component of mid-tolerant species.
  • On better sites, crop tree thinning of mid-tolerants in the understory is important to promote crown development.
  • Overstory UGS trees which are overtopping patches of understory crop trees should be removed.
  • The retention of minimum stocking levels (i.e. 14 to 16 m²/Ha) to avoid excessive release of AGS crop trees in the understory is important for quality development in the residual stand. This will typically require the retention of some UGS stems.
  • AGS mid-tolerant hardwood, pine, hemlock and/or spruce seed trees should be retained at a regular spacing to provide opportunities for regeneration of these species.
  • Consider manual or selective chemical tending for timely control of competition around established seedlings.

Commentary on Beech Bark Disease (BBD) Complex

• Beech Bark Disease (BBD) is an invasive non-native insect-fungus complex caused by the beech scale (Cryptococcus fagisuga) and the canker fungus Neonectria faginata. The disease is causing decline and death of beech trees throughout most of its range in Ontario (McLaughlin and Greigenhagen, 2012).
• There is no control for beech bark disease and as the disease spreads throughout Ontario, beech trees will continue to decline.
• Three distinct phases of beech bark disease development can be observed across Ontario:
  • The Advancing Front, refers to stands in which beech scale populations have recently colonized unaffected beech trees. Larger, older trees support the building populations of beech scale.
  • The Killing Front is characterized by high populations of beech scale insects, Neonectria attacks, developing cankers and heavy tree mortality.
  • The Aftermath Forest, where disease has passed through and remains endemic. Large remnant trees will continue to decline and younger trees will become infected, disfigured and gradually decline.
• Rapid tree mortality (Killing Front) generally occurs 3 to 6 years after the scale insects infest an area and with the appearance of Neonectria. The rate of decline and mortality can take longer if the area is a great distance from other infected beech trees or the amount of fungal inoculum is low. Severe drought or other tree stressing events such as defoliation have been associated with Neonectria invasion. The Parry Sound and Huntsville areas experienced the killing front in 2010, with approximately 50% beech tree mortality occurring within a 3 year period followed by significant additional damage caused by beech snap.
• BBD resistance vs BBD tolerance: Resistance to BBD is defined as resistance to the scale insect. If a tree in a heavily scale infested area has no scale on it, then it cannot become infected with BBD. In North America, 1% to 5% of trees exhibit resistance. Tolerance is the ability of a tree to limit the impact of N. faginata infection by preventing its radial and lateral spread by means of chemical and/or callus barriers.
• Residual and regenerating stands may be dominated by susceptible beech, capable of forming thickets that prevent the regenerating of other species and offering no economic and reduced ecological value as BBD continues to kill susceptible beech over time.

Managing Beech Bark Disease

The following general principles are based upon the cited documents from Michigan and Ontario and the knowledge and experience of Ontario silviculture scientists and practitioners.

General principles for managing stands in all phases of BBD development

• In the absence of complete knowledge of the impacts of BBD throughout the range of beech and response of beech to different management options, forest managers will need to implement and evaluate a variety of silvicultural options to limit losses to BBD and maintain long-term forest health and biodiversity. The suggestions are intended as helpful advice but should not limit other options from being explored.
• The identification and retention of potentially resistant and tolerant trees is a top priority for conserving the genetic diversity of beech.
• Tree markers need to be aware of the importance of retaining a component of beech for wildlife (mast, cavities, stick nests) and diversity as per the Stand and Site Guide.
• Because of the serious concern with loss of beech for mast production, retention and regeneration of other mast producing species (e.g. oak, hickory) is critically important.
• Beech is often abundant as advanced seedling regeneration and as root sprouts from declining or dead stems. These seedlings/ sprouts are also susceptible to beech scale. Manual, mechanical and herbicidal methods may be considered to control advanced beech regeneration or beech root suckers in BBD-affected stands.
• Minimize harvesting injuries to beech root systems to reduce subsequent root sprouting.

Site specific guidelines

Factors that affect development of beech bark disease include species composition and density of stands, and the size, age and vigor of trees within a stand. Selecting a proper management strategy depends on the disease status of the stand, as well as the management objectives. Management guidelines are presented here for stands that are (1) not yet infested by beech scale, (2) within the Advancing Front, (3) within the Killing Front and (4) in the Aftermath Forest.

Identifying potentially tolerant and resistant trees

Outside of the aftermath forest, it will be very difficult to identify tolerant or resistant trees with any certainty. The following photos (credit: Martin Streit) illustrate infected (left) and smooth bark healthy (right) trees referred to in the text. Smooth barked uninfected trees may have an increased chance of being resistant or tolerant, particularly when next to trees with heavy scale or neonectria cankers.

5.1.6 Lowland hardwood

The lowland hardwood group includes black ash, balsam poplar, green ash, white elm, red maple, silver maple, yellow birch and common associates growing on hydric substrates (e.g. ecosites 130-133). Common landform associations include flood plains, oxbow swamps, toe slopes, and localized depressions. The composition of individual stands can vary from single to multiple species with nearly pure stands (e.g. black ash or red maple) not uncommon. Substrates are typically deep, can be mineral or organic, and wet to saturated with seasonal standing water common. Species vary from intolerant (balsam poplar), to intermediate (e.g. green ash) to tolerant (e.g. red maple) of shade. Management approaches should be matched to species present but typically includes some form of partial harvesting.

Keys to success:

Cautions:

Recommended reading:

Target species: Lowland hardwood

Suggested management approaches – Lowland hardwoods

Lowland hardwood forests are typically dominated by major species red/silver/freeman maple, green/black ash and white elm. Depending upon geography and soil moisture minor species can include white cedar, yellow birch, hemlock, red/ white/ black spruce, bur oak, basswood, aspen spp, balsam poplar, eastern cottonwood, black willow, white birch, tamarack, balsam fir, white pine, and shagbark/ bitternut hickory. Additional species in southwestern Ontario can include swamp white oak, black walnut, tulip, hackberry and sycamore. All management approaches must be evaluated in context of site sensitivity and hydrology as described in commentary which follows the main text.

Option 1 – Group selection: The objective is to manage for an uneven-aged lowland hardwood forest.

Option 2 – uniform shelterwood (three cuts): Objective is the renewal of an even-aged lowland hardwood dominated forest

Regeneration cut

First removal (release cut)

Final removal cut

Irregular shelterwood

Commercial thinning

Commentary on Lowland Hardwood Management

Lowland hardwood forests are particularly sensitive sites because the hydrology of the site can be easily affected by access and harvest operations. The water table is typically at or close to ground level, and ponding and/or running water is typical. Root systems are shallow and trees prone to windthrow. Damage to the trees and site can occur easily if logging is carried out during the wetter/ frost-free seasons. For many of these sites harvesting is not feasible, or may only be possible during short time periods where the ground is frozen hard or extremely dry. At all times managers should be careful to avoid over-cutting lowland hardwood stands, which may lead to elevated water tables, an increased risk of windthrow and/or a conversion to non-forest cover, as well as off-site impacts related to drainage and habitat change.

Natural disturbances in lowland hardwood stands are typically flooding and/or wind throw. Moderate wind disturbances tend to kill mid story trees while super canopy trees and saplings have a lower probability of being killed. Analysis of black ash stands around Lake Nipissing showed that individual trees were killed by flood events resulting in multi- aged stands in the majority of the stands studied (Townshend 2012). Group selection or single tree selection are silvicultural systems that most closely match the effects of the natural disturbances these tree species have adapted to. The uniform shelterwood and irregular shelterwood silvicultural systems create conditions similar to the more intense flood and wind disturbance events.

Commentary on Emerald Ash Borer (EAB)

Increasing tree species diversity in lowland hardwood forests can help to mitigate the impact of the EAB threat. After EAB infestations the death of the ash trees creates very open conditions in ash-dominated forests. If vigorous advanced regeneration of other tree species is present in the forest understory they will respond to the increase in light conditions and dominate the new forest. However if advanced regeneration is small or sparsely distributed, there is a significant risk that water tables may rise, windthrow may occur, and/ or herbaceous, brush or invasive species may take over.

Forest managers can control the location and size of canopy openings and the selection of residual trees to encourage the regeneration and growth of tree species other than ash.

The documents “Preparing for Emerald Ash Borer (Streit, 2012)” and “Suggested Prescriptions for Managing Ash in Farm Woodlots (Williams and Schwan, 2011)” provide recommendations to help managers diversify ash forests and better withstand an outbreak of emerald ash borer.

5.1.7 White ash

White ash (Fraxinus americana) is shade tolerant when young and progressively less tolerant with age. Best growth is on moderately well drained loams derived from a nutrient rich parent material. White ash has some tolerance for flooding but is more common on fresh to dry sites at the northern limits of its range. Regeneration is from both seed and stump sprouts. Suitable seedbed can vary (mineral soil, humus, leaf litter, etc.) provided adequate moisture is maintained. Seedlings may take several (3-15) years to reach breast height but will grow relatively fast once established. Stump sprouts may be as few as one or two per stump and grow faster than seedlings. Light demands increase with age and moderate (e.g. 50%) to full light is required to reach pole size and larger. White ash is commonly managed through the shelterwood and selection silviculture systems as an associate with other species but can successfully regenerate in clearcuts when provided an early competitive advantage. The emerald ash borer insect presents significant challenges for perpetuation of ash in Ontario.

Keys to success:

Cautions:

Recommended reading:

Target species: White ash

Suggested management approaches – white ash

Option 1 – Selection harvest: Objective is the maintenance of a minor component of white ash in an uneven-aged matrix of tolerant hardwoods.

Option 2 – Group selection: Objective is management of an uneven-aged tolerant hardwood forest with a white ash component.

Where feasible, schedule group expansion to maintain adequate light levels (~50%).

5.1.8 Butternut

Butternut (Juglans cinerea) is a common yet not abundant tree that typically inhabits the southern portions of the Great Lakes–St. Lawrence forest. It is an endangered species on the Species at Risk in Ontario (SARO) List. Its main threat is an introduced fungal disease, butternut canker, but premature harvests may also be affecting recovery.

Butternut grows best on well-drained, fertile soils in shallow valleys or on gradual slopes. Although young trees may withstand competition from the side, butternut does not survive under shade from above. It must be in the overstory to thrive and is classified as shade intolerant. Good seed crops occur every 2-3 years and seed falls within the vicinity of the parent tree unless it is further transported by rodents or water. Germination typically occurs in the spring following seed fall but seed can remain viable in the ground for 2 years. The species is fast growing and also has the ability to reproduce vegetatively through stump sprouting from young trees/saplings.

Because butternut is intolerant of shade, forest harvesting can be used to regenerate the species, but indiscriminate harvesting of butternut itself may remove potentially resistant genetic material.

Keys to success:

Cautions:

Recommended reading:

5.1.9 Balsam poplar

Balsam poplar (Populus balsamifera) is shade intolerant, regenerates from root suckers, buried branches, and seed, and is typically clonal. Balsam poplar can be a pioneer species on a wide range of sites but is more typically found on imperfectly drained soils. An ability to produce adventitious roots allows it to tolerate low lying areas with seasonally inundated soils. Regeneration from suckering can be very dense with rapid self-thinning. Regeneration from seed is less common but can be significant when moist mineral soil is available in spring for extended periods (e.g. active floodplains). Balsam poplar is typically even-aged but can exhibit wide age ranges (50+ years) on flood plain sites.

Keys to success:

Cautions:

Target species: Balsam poplar

Suggested management approach - balsam poplar

Managing for pure balsam poplar stands is not common because it is often found in mixed stands (with trembling aspen, black spruce, balsam fir, white spruce and white birch) and pockets of pure balsam poplar are typically bypassed. A management approach is described when balsam poplar is present in the pre-harvest stand and targeting balsam poplar dominated mixedwood regeneration.

Option 1 – Clearcut Natural (Coppice): Objective is the renewal of an even-aged balsam poplar dominated mixedwood forest

5.1.10 Large-toothed aspen

Large-toothed aspen (Populous grandidentata) and trembling aspen are very similar in their silvics and response to management. The direction for trembling aspen (section 5.1.11) applies equally to large-toothed aspen. Although very similar, it is important to note large-toothed aspen canopies may provide better light conditions for regeneration and development of other species due to a later leaf flush in spring and rapid leaf response to summer drought and other stresses.

5.1.11 Trembling aspen

Trembling aspen (Populus tremuloides) is shade intolerant, regenerates prolifically from root suckers, and is strongly clonal. Best growth is on loamy nutrient rich soils, particularly those with a calcium component derived from limestone or other calcareous parent material. Aspen will tolerate dry sites, grows poorly if at all on saturated sites, and exhibits best growth on fresh and moist sites. Early regeneration is typically in the 10’s or 100’s of thousand per hectare with rapid self-thinning. Regeneration from seed is possible but unreliable in a natural setting. Aspen is normally managed through the clearcut silviculture system with complete, or nearly complete, overstory removal to stimulate root suckering and provide full sunlight for good growth of suckers.

Keys to success:

Cautions:

Target species: Trembling aspen

Suggested management approach – trembling aspen

Option 1 – Clearcut natural (coppice): Objective is the renewal of an even-aged aspen-dominated forest

Option 2 – Clearcut natural with pre-harvest herbicide: Objective is the renewal of a moderate density of aspen mixed with other species.

Man, R., J.A. Rice, L. Freeman, and S. Stuart. 2011a. Effects of pre- and post-harvest spray with glyphosate and partial cutting on growth and quality of aspen regeneration in a boreal mixedwood forest. For. Ecol. and Manage. 262: 1298-1304.

Man, R., J.A. Rice, and G.B. MacDonald. 2011b. Early effect of pre- and post-harvest herbicide application and partial cutting in regenerating aspen - jack pine mixtures in northeastern Ontario. CJFR 41: 1082-1090.

Suggested decision key when determining the appropriate management approach for trembling aspen (assumes even-aged aspen regeneration objective).

5.1.12 Black cherry

Black cherry (Prunus serotina) exhibits moderate shade tolerance when young but requires full or nearly full sunlight to develop past the sapling stage. Best growth is on moist, rich, well-drained loamy soils and favours cool sites such as north and east facing slopes. Seeds fall within the vicinity of the tree, can remain viable in the soil for multiple years (but not decades as previously thought), and produces good crops every 3 to 4 years. Seedling banks can be a significant source of future regeneration after release. Stump sprouts are common but often have poor form and develop early rot. Cherry is typically managed through large group openings centered on concentrations of cherry, but good regeneration can occur in clearcuts when cherry is provided an early advantage over competition.

Keys to success:

Use large openings when return harvest (e.g. surrounding forest is on a selection cycle) is unlikely.

Cautions:

Target species: black cherry

Suggested management approaches – black cherry.

Option 1 – Group selection: Objective is management of an uneven-aged tolerant hardwood forest with a black cherry component.

Option 2 – Uniform shelterwood (two cut): Objective is the renewal of an even-aged black cherry dominated forest

Regeneration cut

Final removal cut

Option 3 – Clearcut: Objective is regeneration of an even-aged stand with low densities of black cherry.

5.1.13 Red oak

Red oak (Quercus rubra) is mid-tolerant of shade and can grow on a wide range of sites from dry rocky ridges to moist lower slopes. Best growth is on fresh-moist well drained soils on middle to lower slope positions but it is often found on dry sites including ridges and shallow rocky areas. It regenerates from both acorns and stump sprouts with smaller diameters sprouting better than larger ones. Acorns require access to mineral soil to successfully establish. Clipped/damaged/burned seedlings normally re-sprout and can be equal or greater vigour than the parent seedling. Stands of red oak are typically managed through the shelterwood system while isolated concentrations may be managed through group selection.

Keys to success:

Cautions:

Recommended reading:

Target species: red oak

Suggested management approaches – red oak

The following options present typical management approaches when red oak is present in the pre-harvest stand and selected as the management objective.

Option 1 – Uniform shelterwood (two or three cut): Objective is the renewal of an even-aged red oak-dominated forest

Regeneration cut

First removal (release cut)

Final removal cut

Option 2 – Group selection: Objective is management of an all-aged tolerant hardwood forest with a red oak component

Option 3 – Clearcut with seed trees: Objective is renewal of an even-aged intolerant hardwood forest with a red oak component

Key A. Suggested decision key when determining the appropriate management approach for red oak (assumes red oak is desired and present in the pre-harvest stand).

Key B. Suggested decision key when determining the appropriate management approach for red oak (part B).

Key C. Suggested decision key when determining the appropriate management approach for red oak (part C).

5.1.14 Basswood

American basswood (Tilia americana) is tolerant of shade, does not occur in pure stands, and is considered a nitrogen demanding species. Common sites include fresh to moist sandy and silty loams on north and east facing slopes, but it can occur on coarse soils, rock ridges, and very moist lower slopes with telluric drainage. Regeneration is from both seed and stump sprouting. Ideal seedbed is well decomposed humus with consistent moisture. Stump sprouts are normally of good quality, present an opportunity to out compete commonly associated maple seedlings after release, and are often the dominant form of regeneration. Shade will improve initial survival of seedlings but growth is limited without a moderate opening of the canopy. Basswood shade tolerance progresses contrary to many associates with larger trees being more tolerant than seedlings and saplings. Basswood is typically managed through selection and shelterwood silviculture systems but can successfully regenerate in clearcuts, particularly from stump sprouts.

Keys to success:

Cautions:

Target species: Basswood

Suggested management approaches – basswood.

Option 1 – Single tree selection: Objective is the maintenance and improvement of an un-even aged tolerant hardwood stand with a basswood component.

Option 2 – Group selection: Objective is the maintenance and improvement of an un- even aged shade tolerant hardwood stand with a basswood component.

5.1.15 Other hardwood group

This broad group includes oaks (white, bur, etc.), hickories (bitternut, shagbark, etc.), black walnut, ironwood, tulip tree, sassafras, green ash, and others. This guide provides only limited information for these species. Refer to section 5.3.5 for suggested group selection opening size when targeting regeneration of these species. When managing for these species the silviculturalist is encouraged to use the best available information, including that found in the Silviculture Guide to Managing Southern Ontario Forests (OMNR, 2000), and the Tree Marking Guide (OMNR, 2004). Consultation with other experienced practitioners is strongly encouraged.

5.1.16 Balsam fir

Balsam fir (Abies balsamea) is very tolerant of shade, is more common in mixed and late successional forests, and highly susceptible to fire and periodic spruce budworm infestations. It can occur on a wide range of soils including mineral and organic/mineral transitions but exhibits limited growth on dry, nutrient poor (e.g. pure sand), or saturated sites. Balsam fir will germinate on almost any substrate that remains moist, but loamy mineral soil with an organic component provides the best chance for establishment. Light demands are very modest and advance regeneration is common under a wide variety of canopy conditions. Regeneration densities can be very high with severe inter-specific competition. High heat and surface drying associated with open growing conditions can be lethal to young seedlings. Balsam fir responds well to release, may exhibit some stress when moved from full shade to full sun, and can produce enough shade to significantly limit regeneration of other species on the same site. Competition from herbs, woody shrubs and hardwood stems can be significant (e.g. smothering) but rarely kills established (i.e. 15cm+) seedlings. Balsam fir is rarely targeted for regeneration but often forms an undesirable component of the future stand in many species mixes and all silviculture systems. Efforts to actively supress balsam fir include prescribed fire, motor- manual cleaning, blading, trampling with machinery/bunches during extraction, and ‘mowing’ when a live head harvester is available.

Keys to success:

Cautions:

Target species: balsam fir

Suggested management approach – balsam fir

Option 1 – Clearcut natural advance regeneration: Objective is the renewal of an even-aged balsam fir-dominated (>50% composition) mixedwood forest

5.1.17 Eastern larch

Eastern larch (Larix laricina) is shade intolerant, is often a pioneer species, and occupies a very wide range of sites from upland gravel to lowland peats. It is most common on wet organic soils, exhibits best growth on moist well-drained loamy soils and it may succumb to drought on very coarse or shallow soils. In peatlands, rich substrates (i.e. woody vs sphagnum peat), and moving (i.e. aerated) water provide better growth than bogs. Regeneration is from both layering and seed with seed being the most common. Suitable seedbeds include mineral soil, moist organic, and sphagnum mounds. Early losses from damping off associated with aggressive sphagnum, fluctuating water levels, shade, and herbaceous competition can be significant. Larch requires full or nearly full sunlight at all stages of development from seedling to mature tree. As such it is best suited to the clearcut silviculture system but individual trees are known to regenerate in larger shelterwood openings, along skid trails and landings.

Keys to success:

Cautions:

Recommended reading:

Target species: Eastern larch

Suggested management approach – eastern larch

Option 1 – Clearcut natural seed: Objective is the renewal of an even-aged larch- dominated forest

5.1.18 White spruce

White spruce (Picea glauca) is tolerant of shade, is more common in mixed and late successional forests, and rarely forms pure stands. White spruce can tolerate a wide range of site and climatic conditions but grows best on fresh to moist nutrient rich soils including telluric, shoreline, and floodplain sites. Regeneration is exclusively from seed on a wide variety of seedbeds including rotting logs, feathermoss, and exposed mineral soil. Thick (5+cm) litter layers, particularly if exposed and prone to drying out, will limit establishment. Good seed years typically occur every 2 to 6 years, may be as long as 10 to 12 years in some locations, with a poor seed year always following a good one. White spruce tolerates low light levels for long periods and responds well to eventual release. White spruce is managed through both the shelterwood (particularly when mixed with other shelterwoodable species) and clearcut silviculture systems including intensively managed plantations.

Keys to success:

Cautions:

Target species: White spruce

Suggested management approaches – white spruce

The following example management approaches are described when white spruce is present in the pre-harvest stand and when targeting a white spruce component in a future mixedwood regeneration scenario.

Option 1 – clearcut plant: Objective is the renewal of an even-aged conifer dominated forest with a white spruce component

Option 2 – clearcut plant: Objective is the renewal of an even-aged spruce-aspen mixedwood forest

Option 3 – Clearcut natural seed: Objective is the renewal of an even-aged mixedwood forest with a white spruce component

Option 4 – Uniform shelterwood: Objective is the renewal of an even-aged white spruce dominated mixedwood forest

5.1.19 Black spruce

Black spruce (Picea mariana) is tolerant to mid tolerant of shade, regenerates from both seed and layers, and can be even, multi, or uneven aged. Black spruce can occupy a very wide range of sites from shallow till over bedrock to deep sands, loams, clays, and wet organics - best growth is on fresh to moist silty loams. It can be a significant component of successional forests on upland sites, but it is most common in pure or nearly pure stands on wet soils including deep clays and peats. Black spruce will germinate on a variety of substrates (mineral, mixed mineral, humus, sphagnum, etc.) where adequate moisture is maintained. Layering is quite common on organic sites with site richness (poor), stand structure (open) and amount of woody brush (low) influencing the presence of layers. Black spruce will grow in as little as 30% sunlight and optimally in 60% or better light. Black spruce is most commonly managed through the clearcut silviculture system but it’s shade tolerance makes it well suited to shelterwood and selection. Typical harvest patterns include the retention of small to medium stems and concentration of machinery on narrow travel corridors to retain advance regeneration and avoid disturbance of the forest floor.

Keys to success:

Cautions:

Recommended reading:

Target species: Black spruce

Suggested management approaches – black spruce

Alternative management approaches are summarized below when black spruce is present in the pre-harvest stand and when targeting pure black spruce or black spruce dominated regeneration. Conditions within a harvest block (species composition, post-harvest competition, moisture regime, etc.) can be quite variable and may require stratification into separate treatment units. Treatment units should be of a minimum size to facilitate efficient renewal, tending, and future harvests. This may require sub-optimal treatment of some areas based on a pragmatic approach to the whole.

Option 1 – Clearcut natural seed: Objective is the renewal of an even-aged black spruce-dominated forest

Option 2 – Clearcut direct seed: Objective is the renewal of an even-aged black spruce-dominated forest

Option 3 – Clearcut natural advance regeneration: Objective is the renewal of an even-aged black spruce-dominated forest

Option 4 – clearcut plant: Objective is the renewal of an even-aged black spruce- dominated forest

Option 5 – Uneven-aged management: Objective is the maintenance/creation of an uneven-aged black spruce-dominated forest

Suggested decision key when determining the appropriate management approach for black spruce.

5.1.20 Red Spruce

Red spruce (Picea rubens) is tolerant of shade, long lived, and the least common conifer species in Ontario. It can grow on a wide range of sites when moisture is adequate, grows well on fresh to moist sandy loams, and is considered acidophilous (only grows on acidic soils). Regeneration occurs almost exclusively from seed with good seed years occurring every 3 to 8 years. Germination and establishment can occur on a range of substrates (mineral, mixed mineral, logs, humus, etc.) when adequate moisture and moderate temperatures are maintained - drying for even short periods of time can cause failure. Soil disturbance will encourage root establishment into mineral soil, reducing the risk of drying out. Seedlings can survive in as little as 10% full sunlight but require 50% or better light for optimal growth. Once established, seedlings/saplings can remain supressed for decades and still respond well to release, although older trees may require up to 5 years to show increased growth. Red spruce rarely forms pure stands in Ontario and is typically managed based on associated species through the selection and shelterwood silviculture systems. Even small concentrations of red spruce are ecologically significant and should be stratified for retention or a red spruce specific prescription.

Keys to success:

Cautions:

Target species: Red Spruce

Suggested management approaches – red spruce

The ecological characteristics and adaptations of red spruce are similar to those of hemlock. The suggested management approaches for hemlock provide a reasonable starting point for red spruce. Refer to section 5.2.25.

5.1.21 Jack pine

Jack pine (Pinus banksiana) is intolerant of shade, regenerates exclusively from seed, and is adapted to stand replacing fires. It can tolerate a wide range of sites from thin soils over bedrock to deep silts/clays, performs best on fresh well-drained loams, but is found most often on deep dry to fresh sands where fire return interval tends to be lower and competition is not as severe. Jack pine seed banks in the canopy and logging slash (serotinous cones) and requires high temperatures to release the seed. Germination occurs on mineral or burned seedbeds where adequate moisture is present. Spring droughts can lead to delayed germination with some seed germinating the following year. Hardwood and herbaceous litter can smother small germinants, and seedlings are sensitive to even moderate competition. Rapid early growth and high initial densities leads to early stem exclusion and self-thinning. Jack pine responds well to release if not significantly supressed (i.e. good live crown ratio) and is commonly thinned at multiple development stages. Jack pine is managed through the clearcut silviculture system and is typically planted or artificially seeded.

Keys to success:

Cautions:

Recommended reading:

Target species: Jack pine

Suggested management approach – jack pine

Option 1 – Clearcut Aerial Broadcast Seed: Objective is the renewal of an even-aged jack pine-dominated forest

Option 2 – clearcut plant: Objective is the renewal of an even-aged jack pine- dominated forest

Option 3 – Clearcut natural ingress: Objective is the renewal of an even-aged jack pine-dominated forest

Suggested decision key when determining the appropriate management approach for jack pine

5.1.22 Red pine

Red pine (Pinus resinosa) is mid to intolerant of shade, with light requirements increasing with age, and is adapted to frequent ground fires. Red pine can tolerate very dry and poor sites, occurs primarily on deep coarse textured soils (e.g. glacial outwash), with improved growth on fresher sites with a silt/loam component. Red pine prefers acidic soils - sites with moderate to strongly alkaline c-horizon soils have been associated with increased risk of decline. Good seed years are every 3 to 7 years (bumper every 10 to 12) with little seed in the intervening years. Lateral roots extend well beyond the limit of the crown, can send tap and sinker roots very deep into the soil, and commonly graft with roots of other red pine. Red pine is managed through both the shelterwood (particularly when mixed with other shelterwoodable species) and clearcut silviculture systems including intensively managed plantations. Environmental conditions under red pine plantations may be well suited to long-term conversion to hardwoods, white pine, and other mixes.

Keys to success:

Cautions:

Recommended reading:

Target species: red pine

Suggested management approach – red pine

Option 1 – Uniform shelterwood (two to three cuts): Objective is the renewal of an even-aged red and white pine-dominated forest

Option 2 – clearcut plant: Objective is the renewal of an even-aged red pine-dominated forest

Option 3 – Clearcut with seedtree: Objective is regeneration of red pine ranging from dominant condition to a moderate component in a matrix of other species.

5.1.23 Eastern white pine

White pine (Pinus strobus) is mid-tolerant of shade, regenerates exclusively from seed, is adapted to frequent ground fires, and can be very long-lived. White pine can tolerate a wide variety of soils, grows best on fresh to moist loams, and does poorly on heavy clays and saturated soils. Although growth is best on deep loams, more often white pine is found on drier coarse or shallow soils where competition is lower. Good seed years are generally 3-5 years apart with bumper crops every 10-12 years. Concentrations of white pine are typically managed through the shelterwood silviculture system with lower densities managed through clearcut with seedtrees. White pine blister rust and white pine weevil can significantly influence survival and quality.

Keys to success:

Cautions:

Recommended reading:

Target species: Eastern white pine

Suggested management approach – white pine

(Note: all canopy closure references refer to measurements taken with a densiometer)

Option 1 – Uniform shelterwood (two to four cuts): Objective is the renewal of an even-aged white pine-dominated forest

Overall comments

Preparatory cut

Regeneration cut

First removal (release cut)

Final removal cut

Option 2 – Clearcut with seed trees: Objective is maintain or increase the white pine component in a matrix of other species.

Option 3 – Clearcut, restoration: Objective is to create an even-aged white pine- dominated forest on a suitable site

Option 4 – Commercial thinning

Option 5 – Rehabilitation of failed shelterwood cuts.

Commentary on white pine mixtures (red pine, red oak, hemlock, white spruce)

The direction for white pine management presented here is aimed largely at actively regenerating white pine as the target species. However, many “white pine” forests of Ontario are comprised of other desirable species which could and should be accommodated in silvicultural regeneration strategies of the forest as may be reflected in forest management plans. Red pine is often a close cohort of white pine and is linked with white pine in both thresholds for silvicultural decisions (e.g. the combined stocking of white and red pine) and provincial policy.

Red pine does show some shade tolerance when very young but is generally considered a shade intolerant species. As such, in non-uniform white pine stands, marking and supplemental treatments can favor red pine in parts of the stand where white pine stocking is very low while white pine remains the primary target species in areas where white pine provides a relatively well stocked and uniform overstory. The regeneration of species such as spruce, oak and hemlock might also be accommodated through silvicultural planning within white pine stands according to the specific needs of those species. Therefore, the direction on white pine management can and should be modified to accomplish forest management planning objectives of regenerating multiple species in appropriate white pine stands.

PW-A. Suggested decision key when determining the appropriate management approach for eastern white pine (part A). Assumption is white pine regeneration objective and no recent (~20 years) harvest.

PW-B (need to establish regeneration). Suggested decision key when determining the appropriate management approach for eastern white pine (part B).

PW-C (enough regeneration to work with). Suggested decision key when determining the appropriate management approach for eastern white pine (part C).

5.1.24 Eastern white cedar

Eastern white cedar (Thuja occidentalis) is shade tolerant, more common in late successional forests, and can be even, multi or uneven aged. It can tolerate a wide range of sites from dry uplands to deep organics but grows best on moist calcareous soils with moving water and good aeration. Regeneration is from both seed and layering, with layering more common on low lying organics. Germination and establishment requires sustained moisture and is poor on drought prone or saturated substrates. Hummocky terrain can moderate moisture conditions when water table is high (e.g. lowlands) but prone to summer drying on upland sites. Once established, seedlings and layers can tolerate shade for prolonged periods and respond well to eventual release. Height growth is best in moderate light but shoot/root weights are maximized in full sunlight. Presence of deer or high incidence of hare can significantly reduce regeneration. Eastern white cedar is typically managed through shelterwood or strip clearcut silviculture systems.

Keys to success:

Cautions:

Recommended reading:

Target species: Eastern white cedar

Suggested management approaches – eastern white cedar

The following example management approaches are described when cedar is present in the pre-harvest stand and when targeting pure cedar or cedar dominated mixedwood regeneration. These approaches are largely based on the recommendations outlined in Buda et al. (2010).

Like all suggested management approaches included in this guide, the following suggestions should not constrain managers from exploring reasonable alternatives. While there is a reasonable comfort in the categorization (i.e. high, low, not recommended) of approaches (e.g. silviculture system and conditions) included in the management interpretation tables, the specific implementation parameters (e.g. crown closure) in the suggested management approaches below are less certain. Managers are encouraged to record as much detail as possible on site characteristics, pre-harvest condition, and the specific implementation parameters used on different sites to maximize learning potential.

Option 1 – Uniform shelterwood: Objective is the renewal of an even-aged cedar- dominated forest

Supplemental treatments (e.g., fill planting) may be required to meet regeneration objectives.

Option 2 – Irregular Shelterwood: Objective is the renewal of a multi-aged cedar- dominated forest

Supplemental treatments (e.g., fill planting) may be required to meet regeneration objectives.

Option 3 – Group selection: Objective is the renewal of an uneven-aged cedar- dominated forest

Option 4 – Clearcut natural seed: Objective is the maintenance of a minor cedar component in an even-aged mixedwood stand

Commentary on cedar management in deer and moose winter concentration areas

The preceding best management practices reflect the current best knowledge for silvicultural systems for cedar. However in areas of high deer densities, recruitment of cedar past the seedling stage is very difficult due to its preference as winter browse. In these instances, forest managers may need to develop landscape level strategies to address regeneration and recruitment of cedar (e.g. focusing regeneration efforts in peripheral areas with lower wildlife populations), and silvicultural ground rules should reflect these conditions. See section 3.3.3. Ontario Stand and Site Guide (OMNR 2010b) for further guidance.

Suggested decision key when determining the appropriate management approach for eastern white cedar.

5.1.25 Eastern hemlock

Eastern hemlock (Tsuga canadensis) is very tolerant of shade, more common in late successional forests, can be even, multi or uneven aged, and very long-lived. It can tolerate a wide range of sites from dry to very moist and sandy to fine loamy but grows best on cool moist to very moist sites with good drainage. Regeneration occurs almost exclusively from seed with good seed years occurring more than 50% of the time. Germination and establishment can occur on a range of substrates (mineral, mixed mineral, logs, humus, etc.) when adequate moisture and moderate temperatures are maintained - drying for even short periods of time can cause failure. Once established hemlock can tolerate shade for prolonged periods and responds well to eventual release. Height growth is best in moderate light but it can survive as low as 5% full sunlight. Moderate concentrations of hemlock are typically managed through the shelterwood silviculture system with higher densities well suited to selection.

Keys to success:

Cautions:

Recommended reading:

Target species: Eastern hemlock

Suggested management approaches when hemlock is present in the pre-harvest stand and targeting hemlock regeneration. (Note: all three options are regularly applied in Ontario)

Option 1 – Single tree selection: Objective is to manage for hemlock or a hemlock component in an uneven aged forest condition in areas that do not support high deer and moose populations.

Option 2 – Group selection: Objective is to manage for hemlock, or a hemlock component, in an uneven aged forest condition in areas that do not support high deer and moose populations.

Option 3 – Uniform shelterwood (two or three cuts): Objective is the renewal of an even-aged hemlock dominated forest

Regeneration cut

First removal (release cut)

Final removal cut

Irregular shelterwood

Commercial thinning

Commentary on hemlock management in deer and moose winter concentration areas

The preceding best management practices reflect the current best knowledge for silvicultural systems for hemlock. However in areas with a high density of deer and moose during winter (i.e. most deer and some moose winter concentration areas), recruitment of hemlock past the seedling stage is very difficult due to its preference as winter browse.

Regeneration of hemlock cover in the presence of high numbers of deer and moose in winter may not be possible regardless of silvicultural system used (see papers in OMNR, 1992). To maintain high quality cover in hemlock stands in these situations, managers may have to underplant a species such as red spruce. Red spruce is similar to hemlock in terms of shade tolerance, site requirements and snow interception capability but has low palatability to deer (Gordon, 1992). Planting of red spruce may also help re-establish this species, thus meeting broader biodiversity objectives.

Forest managers may need to develop landscape level strategies to address regeneration and recruitment of hemlock (e.g. focusing regeneration efforts in the peripheral parts (i.e. Stratum II) of deer winter concentration areas) and silvicultural ground rules should reflect these conditions.

Suggested decision key when determining the appropriate management approach for eastern hemlock.

*Groups should target established regeneration (with careful logging). New regeneration will require mean square error.

5.2 Managing for multiple species

Mixed species stands tend to be more common as you move from north to south and more common in the GLSL than the boreal. It is not uncommon for stands in the GLSL to have 6 or more species, with none occupying more than 20% of the canopy space. Managing for multiple species on the same site can introduce both challenges and opportunities. This section is presented in two sections; the first being a discussion of mixedwood management, the second presenting the mechanics of using the management interpretation tables when intentionally targeting more than one species.

5.2.1 Mixedwood management

Mixedwood management is a somewhat nebulous term that can mean different things to different people. A very broad definition is the presence of more than one tree species in the same general area. More common definitions narrow this based on a variables such as relative abundance (e.g. <70%), canopy position (e.g. co-dominant), taxanomic differences (e.g. conifer versus hardwood), and ecological traits (e.g. shade tolerance). Some definitions (e.g. OMNR, 2003) consider not only the current forest composition but also the potential of the site, current successional stage, and future vegetation dynamics.

Forest management plans typically include one or more mixedwood forest units with a definition that includes a minimum (e.g. greater than 30%) amount of both hardwood and conifer. The landscape guide (e.g. OMNR, 2010a) includes simulated ranges of natural variation and milestones for mixedwood forest types over long time periods. Forest management activities, including mixedwood management approaches, are then planned to maintain or move towards the desired level. Mixedwood targets may be achieved through maintenance of existing mixedwoods, intentional creation of mixedwoods through silviculture, accidental creation of mixedwoods when targeting other conditions, and mixedwood development through natural succession in unmanaged areas.

To achieve forest level objectives the silviculturalist needs an appropriate set of tools (e.g. SGRs) to maintain, create, or convert mixedwood forest conditions. Management effort is normally aimed at maintaining or enhancing the conifer component. With some notable exceptions (e.g. red oak, black cherry, etc.), hardwoods tend to regenerate with relatively low effort and the focus is on getting desirable species.

5.2.2 Using the management interpretation tables when managing for more than one species

It is quite common to have an objective for more than one species on the same site. However, the management interpretations in this guide are presented by individual species. To manage for multiple species on the same site the practitioner will combine the individual direction for the species of interest, with the site characteristics where management will occur, to develop silviculture ground rules and prescriptions. This approach allows for customization to forest management plan specific forest unit or sub- forest unit mixed species conditions of interest.

Table 5b provides an example of using the designations in the management interpretation tables when two species are targeted on the same site. In this example two combinations (clearcut seed tree and strip shelterwood) have been identified as compatible (i.e. both have a high probability designation), one combination (uniform shelterwood) as potentially compatible (if a low to moderate density of species A is consistent with objectives), and four combinations as not compatible as one or more of the two species are low probability or not recommended.

Table 5b. Example use of management interpretation table designations when two species are targeted on the same site

5.2.3 Resources

A number of resources exist to help the silviculturalist plan both an overall strategy and determine specific implementation parameters for mixed species management. In conjunction with the revision of this guide, two mixedwood management resource documents have been prepared - one each for Boreal (in prep) and Great Lakes-St. Lawrence (in prep) regions have been prepared. Other documents including the Boreal Mixedwood Notes series (e.g. OMNR, 2000), and the results of the Vegetation Management Alternatives Project (e.g. Bell et al.2012) include a great deal of relevant information. Many operational research reports (e.g. Man et al.2013) are available to further inspire and customize local approaches.

As you move further south in the province mixed species stands and mixed species management approaches become much more common. The Tree Marking Guide (OMNR, 2004) includes a number of approaches designed to maintain or enhance desirable components of Great Lakes-St Lawrence mixed species stands.

Across the province there are practitioners with various levels of experience in mixed species management approaches. Perhaps the most valuable resource is a field visit with a knowledgeable colleague to explain what has been tried and what is working at a local level.

5.2.4 Suggested management approaches – mixedwoods

A number of the suggested management approaches for individual species (section 5.2) include mixed species management approaches. These include approaches where a low to moderate density of a single target species is intended and the remaining component of the stand is not explicitly identified, as well as other approaches where more than one species is explicitly targeted.

The following text provides suggested management approaches when targeting a mixture of hardwood and coniferous tree species as a future regeneration objective. A pre-harvest assessment to determine pre-harvest stand (composition and structure) and site conditions will greatly increase the probability of success when matching silviculture system and renewal treatments to site conditions and future forest objectives.

Option 1 – Clearcut with cluster planting: Objective is the renewal of the conifer component of a mixedwood stand through the creation of an even-aged mosaic of strips or patches of conifers between hardwood regeneration.

Option 2 – Pre-harvest underplanting of white spruce: Objective is a two-tiered mixedwood stand (hardwood overstory with a conifer understory) as an alternative to clearcutting and even-aged management.

Option 3 – Pre-harvest herbicide with clearcutting: Objective is the renewal of an even-aged mixedwood forest

Option 4 – Corridor harvest with shearblading: Objective is the renewal of a two- tiered mixedwood stand with corridors regenerated to conifer in between unharvested or partially harvest hardwood dominated strips.

5.2.5 Suggested management approaches – GLSL mid-tolerants

The following text outlines typical parameters for regenerating mid-tolerant and intolerant hardwoods as a minor component in tolerant hardwood forest types.

There are a number of mid-tolerant and intolerant hardwood tree species which occur regularly as a component of the tolerant/ mid-tolerant hardwood forest but rarely, if ever, occur as the dominant species in the stand. When regeneration of these species in the tolerant hardwood forest is an objective, group selection is usually the recommended treatment. A component of these species can also be regenerated through a uniform shelterwood prescription on suitable sites and seedbeds, if sufficient residual seed trees and/ or advanced regeneration are maintained. Table 5c provides the recommendations for incorporating regeneration of these species into group selection and uniform shelterwood prescriptions for management for tolerant/ mid-tolerant hardwood forest types. Further details on the implementation of both systems are provided in the sugar maple, red oak, yellow birch and lowland hardwoods sections.

Table 5c. Recommendations for regeneration establishment and/or initial release of advanced regeneration of selected mid-tolerant species through group selection

Black ash and white birch are of cultural importance to aboriginal people for basket and canoe making. Although they often occur as the dominant species in Ontario’s forests, they are also common as a minor species component in tolerant/mid-tolerant hardwood forest types. Table 5d provides the recommendations for incorporating regeneration of these species into group selection prescriptions.

Table 5d. Recommendations for regeneration establishment and/or initial release of advanced regeneration of black ash and white birch through group selection

Recommendations for regeneration monitoring and maintenance

6.0 Adaptive management

6.1 Introduction

Silviculture is the art and science of growing trees. It is a science in that there is a wealth of information from long-term plot networks, research trials, operational monitoring, physiological studies, theoretical ecology, experiential knowledge, and more that can be used to form a hypothesis (choose appropriate treatments based on predicted outcomes) and test it. But it is also an art in that the large multi-dimensional matrix of desired knowledge used to form a hypothesis has many gaps, many variables are difficult to predict (e.g. weather), and some variables may be difficult to measure or even unknown.

This duality was well described as early as 200 years ago by German forester Heinrich Cotta, in the preface to his book Anweisung zum Waldbau (“Advice on Silviculture” 1816; as cited by Baker (1950)) and is worth repeating here;

Thirty years ago, I prided myself on knowing forestry science well. Had I not grown up with it and in addition had learned it in the universities! Since then I have not lacked the opportunity for increasing my knowledge in many directions, but during this long period I have come to see very clearly how little I know of the depths of the science, and to learn that this science has by no means reached that point which many believe to have been passed.

Many perhaps may be in the condition in which I was thirty years ago; may they in the same manner be cured of their conceit! Forestry is based on the knowledge of nature; the deeper we penetrate its secrets, the deeper the depths before us. What the light of an oil lamp makes visible is easily overlooked; many more things we can see by torchlight, but infinitely more in the sunlight. The lighter it grows around us, the more unknown things become apparent, and it is a sure sign of shallow-ness, if anybody believes he knows it all.

Our foresters can still be divided into empiricists and scientists; rarely are both united. That the former considers sufficient in a forest management is easily learned, and the systematic teachings of the other are soon memorized. But in practice the art of the first stands to a thorough forestry science in the relation as the quack medicine to the true pharmacopoeia; and the other often does not know the forest for the many trees. Things look very differently in the forest from what they do in the books; the learned man stands therefore, frequently, left by his learning and at the same time without the bold decision of the empiricist.

Three principle causes exist why forestry is still so backward:

1. The long time which wood needs for its development,
2. The great variety of sites on which it grows,
3. The fact that the forester who practices much writes but little, and he who writes much practices but little.

The long time period causes that something is considered good and prescribed as such which is only good for a time, and later becomes detrimental to the forest management. The second fact causes that what many declare good or bad proves good or bad only in certain places. The third fact brings it about the best experiences die with the man who made them, and that many entirely one-sided experiences are copied by the merely literary forester so often that they finally stand as articles of faith which nobody dares gainsay, no matter how one-sided or in error they may be.

In the intervening centuries since Cotta captured these thoughts, and particularly in the last few decades, the goal of silviculture has shifted from one of timber production to ecosystem management with timber as one of many desired benefits. Much has been studied, quantified, learned, and indeed in some cases re-learned. The tools and information at our disposal have greatly increased. However, despite these advances, cause and effect is not always obvious, nature is still messy, and things do not always go as planned. This does not mean we throw our hands up in frustration with the occasional failure, but that we embrace the uncertainty with which we are working, and commit to learning through practice. This is the essence of the silviculture effectiveness monitoring (SEM) program outlined in section 6.2.1.

To fully embrace uncertainty and learning through practice we need the courage to be wrong. It is often by trying things that have an uncertain outcome where the most learning occurs. Of course, with uncertainty comes risk, and the potential for learning needs to be balanced with the probability and impact of a negative result. Within this guide, practices believed to have a lower probability of success are categorized as such and those that are unlikely to be successful are categorized as not recommended (see section 5.1). However, this does not automatically prohibit them from occurring. Low probability treatments can still occur as part of a trial area (as described in section 6.2.2) and not recommended treatments can still be carried out as part of an exceptions monitoring program (as described in section 6.2.3).

Learning through practice is greatly enhanced when operating above the level of an individual or small group. It is important to foster an environment where we learn from each other by recording and communicating our successes, failures, and discoveries in a way that is easily translatable across time, sites, and administrative formalities. The framework (i.e. Bayesian belief networks [BBN]) used to synthesize and document the knowledge that supports the direction in this guide is hoped to serve this purpose and be a solid foundation for adaptive management (i.e. learning through practice) moving forward. The BBN framework is used to provide a representation of how we believe the system works, what level of knowledge we have to support that belief, and critical assumptions that can be tested and either supported or disproven as we learn through practice.

6.2 Monitoring and evaluation

Continued learning and innovation can increase the productivity, value, and resiliency of Ontario’s regenerating forests. Our understanding of silviculture treatment effects and effectiveness has evolved through time as a result of past silviculture experimentation, evaluation, and monitoring by scientists and practitioners in formal and informal settings. This guide encourages continued learning to improve silviculture treatments under common use and explore the potential of new and evolving treatments for future operational implementation. This can be achieved through monitoring and evaluating all treatments through a Silviculture Effectiveness Monitoring (SEM) program as well as focused monitoring of specific treatments of interest, particularly those associated with a higher uncertainty (trial areas and exceptions).

6.2.1 Silviculture effectiveness monitoring

Learning through practice is a very intuitive process that is part of human nature. People are inherently very good at observing the world around them and developing conclusions about how it works. Casual learning through observation can be a very efficient way to gain knowledge about a system. Continued observation over long time periods and/or in multiple locations, can allow people to move from observational knowledge to synthesis level understanding of processes and fundamental principles – moving from what to why. However, human nature can also lead to confirmation bias, where we internally emphasize results that fit our belief, and downplay those that do not. To guard against confirmation bias and other human failings requires a more formal articulation of assumptions and a dedicated monitoring and evaluation process using relevant metrics. Ideally we should be able to describe in advance what signals from our monitoring would cause us to change our management approach.

Silviculture effectiveness monitoring (SEM) is a formalized program used to determine if management activities are producing the desired results and why. SEM entails describing the objective, monitoring results, analyzing and understanding trends, and feedback to strategic planning.

SEM may be viewed from various perspectives: at the stand level for particular prescriptions or treatments, at the forest or management unit level for trends within particular forest units, and at the regional and provincial levels to measure program success. Analysis at each level provides answers to the basic questions:

“What did we intend to accomplish?”
“What did we actually accomplish?”
“How well did we do it?” (Robbins (1992))

Some of the components of a SEM program are referenced in the Forest Operations and Silviculture Manual (FOSM) and the Forest Information Manual (FIM), but are presented in a more useable manner in the Silviculture Effectiveness Monitoring Manual for Ontario (SEMMO).

Monitoring associated with the SEM program includes both formal and informal monitoring. All treatment areas are monitored informally to ensure the stand is developing as expected and any necessary follow-up treatments are scheduled appropriately. Informal monitoring varies from ocular assessments to plot-based surveys depending on the complexity of the site and the experience of the practitioner. Formal monitoring occurs at specific milestones (e.g. free-to-grow) that vary based on the silviculture system being employed. These milestones are selected as significant points in the development of the future stand and timed with the development of regeneration in clearcut and shelterwood systems, or shortly after harvest in selection silviculture systems. The results of monitoring are compared with a pre-set performance standard (e.g. renewal standards – see section 4) specific to the treatment package employed on a site by site basis. The results from similar sites are then compared to understand trends.

Figure 6a presents an idealized timeline of activities, including monitoring, for clearcut, shelterwood, single, and group selection.

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There are of course limitations to what an SEM program can accomplish and what conclusions can be drawn from the data. The most important limitation being the realization that milestones themselves (e.g. FTG) are a hypothesis. The free-to-grow standard is an estimate of a condition that will eventually evolve into the desired future forest condition. Assumptions are made about natural stand dynamics, application of future treatments (e.g. pre-commercial thinning), and growth and yield relationships. Each of these assumptions has a degree of uncertainty, that generally increases in more complex (e.g. mixed) stands.

6.2.2 Trial areas

All low probability treatments are conditionally recommended with the condition being that they occur as part of a trial area. This section describes the minimum requirements and limitations of a trial area.

6.2.2.1 Description and limitations

The intent of a trial area is to allow for the initial exploration of an idea, on a limited basis, with minimal administrative encumbrances. Individual trial areas may be undertaken to increase operational efficiency, improve achievement of objectives (i.e. forest condition), improve cost effectiveness, minimize adverse effects, demonstrate an expected failure, or any other number of reasons.

The forest management plan will include enabling text to allow for the implementation of trial areas. This will include information on treatment and forest type eligibility, limitations (e.g. size and number), and any applicable renewal standards (guideline).

The planning team should carefully consider what forest types are eligible for trial area implementation. Forest types that have high diversity value, represent critical species at risk habitat, or are locally uncommon should be paid particular attention. When determining if any forest types should be eligible for trial area implementation, the effect of a failed trial area on achievement of forest management plan targets should be forecast (best management practice).

Details of individual trial areas may not be known at the time of FMP development and opportunities for trial areas may arise at any time. Trial areas can potentially occur on any harvest, renewal or tending operations included in this guide^{footnote 12[12]}by following the FMPM process regarding a stand level change to silviculture treatments.

Prior to trial commencement, a project plan for the trial area will be prepared (standard). The project plan is intended to provide a basic and informal outline of the fundamental trial area details. The project plan will briefly summarize the following (guideline):

• Project objectives and brief rationale,
• Description or map of the site location,
• Description of the project design, and the treatments involved
• Timelines including expected duration of project,
• Renewal standard (if applicable). The minimum renewal standard for a trial area is FRI definition of productive forest.
• Description of project monitoring, evaluation, and reporting of results.
• A description of anticipated re-treatment activities (if any), and associated timelines, should the trial fail to develop as expected or meet the minimum renewal standard.

The project plan will be provided to the MNRF office responsible for compliance prior to commencement of the trial and serve as written notification to the MNRF that the trial area is planned to occur (standard).

Individual trial areas will not normally exceed 100 hectares (guideline). Trial areas exceeding 100 hectares in size will be considered on a case by case basis by the regional director or designate through review and approval of the project plan (guideline).

In some instances, a limited window of opportunity may exist to establish a trial area. Project plans requiring approval (i.e. over 100 ha) should be submitted as far in advance of the desired start date as possible and approval authorities are encouraged to undertake a timely review. Project plans for trial areas less than 100 hectares in size do not require review and approval when the process (e.g. enabling words in FMP) and limitations in this section (section 6.2.2.1) are adhered to.

A maximum of three trial areas can be initiated in any 5 year period (standard). Individual trial areas (new, ongoing, or previous) will be substantially different in scope, objectives, or design to warrant a new investigation (guideline).

6.2.2.2 From trial areas to practice

If the short term findings of a trial area prove to be positive the application of those results to regular practice may be difficult if trial area design or inherent limitations of the trial area approach do not allow for the size, replication, or monitoring effort required to give confidence in the results. It is likely that to change the status of a low probability treatment, or condition on a high probability treatment, in future revisions of this guide, additional investigations beyond the initial trial area will be required. It is hoped that a trial area will serve as an initial proof of concept to encourage interest and investment in a more rigorous investigation.

Collaboration and development of partnerships between forest resource managers, MNRF science and silviculture staff, Canadian Forest Service staff, academic institutions, silviculture contractors, and other partners are encouraged but not required for trial areas to occur. Combining practical expertise together with science and information products, as a result of such partnerships, would optimize investment and uptake of knowledge gained from trial areas for incorporation into future guide revisions and improved silviculture practices.

6.2.3 Exceptions

Forest management guides, including this silviculture guide, are used during the preparation of a forest management plan. Using the silviculture guide includes selection of treatments that are consistent with the objectives described in the forest management plan. When not recommended treatments are selected they are considered an exception. If low probability treatments (see section 5.2) are selected, and not undertaken as part of a trial area, those treatments are also deemed not recommended in this guide and considered an exception.

Inclusion of an exception in a forest management plan requires the development of an exceptions monitoring program. The details of the monitoring program are normally customized to the nature of the exception, the degree of departure from any conditions, and the specific reason and/or circumstances that lead to the exception being included.

The forest management planning manual provides details on the process and documentation requirements of an exceptions monitoring program. When developing an exceptions monitoring program it may be helpful to consider the following questions.

6.3 Approach to effectiveness monitoring

Direction in this guide is based on the best scientific information and expert advice available at the time of writing (see Background and Rationale for Direction Document – in prep). Direction for some species and treatments is based on a large body of scientific literature supported by years of experience. However, direction for some species, and some practices, is based on a more limited body of scientific knowledge relying more heavily on expert opinion. For all direction, there is uncertainty associated with the outcome of its application. Uncertainty arises for numerous reasons. For example, there may have been few studies upon which to base direction, studies may have been conducted in a different ecological context, results of studies may have been inconclusive or even contradictory, and practitioners may have had success in some locations but failures in others without a clear understanding of the difference. Direction that is uncertain can be viewed as a hypothesis that requires testing within the context of the suite of forest management operations practised across Ontario’s ecologically diverse landscape.

The declaration order regarding MNRF’s Class Environmental Assessment Approval for Forest Management on Crown Lands (MNR-71 as amended by MNR-71/2) implicitly recognizes uncertainty and stipulates the following conditions associated with testing the effectiveness of forest management guides:

38(f). Each revised, amalgamated, or new Guide shall contain a description of an approach that shall be undertaken to monitor the effectiveness of the Guide.

and

31. MNR shall maintain a program of scientific studies to assess the effectiveness of Guides. Updates on the progress of these studies shall be provided to the Provincial Forest Technical Committee to assist in the review and revision of Guides.

The following two sections address each of these declaration order requirements.

6.3.1 Guide effectiveness

Testing the effectiveness of guide direction forms one part of the guide development cycle. The stated purpose of this guide as described in section 1.1 is:

...to provide practitioners and forest management planning teams with information and direction to determine which silviculture activities are effective in meeting local forest management objectives.

Testing the effectiveness of this guide then involves testing if the sum of silviculture planning and implementation leads to achievement of forest management objectives. To isolate cause and effect, the achievement of forest management planning objectives can be broken down into 2 separate but related questions;

The first component will be tested using the silviculture effectiveness monitoring program described in section 6.1. This may include drawing on the conclusions of individual forest management unit analysis or a roll-up and analysis at broader scales.

If it is found that the guide is effective in helping achieve the first component, it may still be possible that forest management plan objectives will not be achieved. This is partly a test of the planning teams ability to translate forest management objectives into forest condition parameters, but also a test of underlying assumptions that the silviculture approaches described in this guide will create the expected function. Function may be for wildlife habitat (e.g. structural diversity), timber products (e.g. piece size), or any number of purposes. The approach to testing the effectiveness of the Landscape (OMNR 2010b, OMNR 2010c) and Stand and Site (OMNR 2010a) guides will be relied upon to test the assumption that silviculture activities will create a forest condition that conserves biodiversity at site, stand, and landscape scale. Other forest management plan objectives (timber, viewsheds, etc.) are difficult to test above a management unit scale as they are specific to each plan. Feedback from the regular forest management planning reporting, monitoring, and auditing program will be relied upon for this purpose.

6.3.2 Evolution of knowledge

Many individual pieces of direction in this guide do not require rigorous testing because they are based on an extensive body of scientific evidence, have been used successfully for decades, or may already have been tested within the context of Ontario’s forest management practices (see Background and Rationale for Direction – in prep). The outcome of these practices will continue to be checked through regular monitoring (e.g. section 6.2.1) to ensure these assumptions hold true.

Conversely, there are other pieces of direction in this guide for which there is greater uncertainty associated with the outcome of their application and where new or expanded knowledge would be very useful.

The MNRF will use a number of different approaches to facilitate the acquisition and dissemination of new knowledge that will aid in addressing these uncertainties:

The Bayesian Belief Networks (BBN) created to support the development of this guide provide a foundation to build from. They provide a description of how we think the system works (i.e. what variables matter and how they relate), what information we have to support that view, and which variables are the most influential on a successful result. By its very definition a BBN is not intended to be a static document, but rather provides a structured framework by which new information can be incorporated. As new information becomes available the BBN will be periodically updated. The new information will either increase the certainty of the existing network (i.e. strengthen the belief), decrease the certainty but not change the structure, or require a structural change to add, remove, or modify a relationship. When the BBN changes, the influence of that change on the conclusion (i.e. management interpretations) will be examined. If the change to the BBN suggests a different management interpretation is required, that information will be communicated to forest managers and considered during the regular schedule of guide review.

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Appendix 1 – History of silvicultural guides in Ontario

Prepared by J. A. Rice, RPF August, 2013.

Ontario’s formal recognition of the forestry profession began in the early part of the 20^th century with the establishment of the province’s first forestry school in 1907 and the appointment of the province’s first chief (provincial) forester in 1912.

Early efforts by the Ontario government in forestry focussed primarily on the afforestation of abandoned lands in southern Ontario. The Ontario Department of Lands and Forests (ODLF) oversaw the production of a number of forestry related documents primarily aimed at providing guidance for woodlot owners, typically farm woodlots, in the southern part of the province.

During that same period, while timber harvesting was occurring in central and northern Ontario, there were few documents produced that focussed on managing the vast tracks of Crown land in that region, as the province’s focus there was on fire protection (e.g., the passing of the Forest Fires Protection Act in 1917).

It wasn’t until the late 1940s and early 1950s, after World War II, that the province took the next step to managing Crown forests and produced a “Manual for Timber Management” (ODLF 1948). The manual was made up of 5 separate booklets covering legislation, timber estimating (field work), timber estimating (compilations), timber marking for partial cutting operations, and methods of stumpage appraisal. While this manual spoke of the need to consider silviculture, it provided little direction or advice on methods to grow healthy and productive forests. A revised edition of this manual was produced in 1951.

The next advances took place in the late 1960s and early 1970s. In this period land-use issues in the province, including how forests were managed, were being examined and debated by experts as well as the public. The resulting changes and transformations that came out of these discussions included the province reviewing its approach to managing Crown forests.

During that time, factors that drove the changes included:

These factors helped the province to decide to develop and distribute a series of silvicultural guides. These guides were designed to provide forest managers a set of stand-alone documents with all the information they needed to manage forest blocks of commercially important species in an efficient and effective manner. In theory they would also lead to more consistent and predictable approaches to management across the range of a species or working group (working group was a term used to describe the leading species in a stand, see previous FRI specifications for details).

The decision to produce silvicultural guides was not unique to Ontario. Similar factors and discussions were occurring in other provinces and throughout the United States. Each jurisdiction was searching for better methods to manage their forests, and most decided to produce guides to help address these concerns. Examples of guides from other jurisdictions included an aspen guide in the Prairie Provinces (Steneker 1976), and a spruce-fir guide in the US northeast (Frank and Bjorkbom 1973) to name but two.

The evolution of silvicultural guides in Ontario from the late 1960s until today closely follows the changing view that society has put on our forested landscape. The guides have evolved from having timber oriented goals based primarily on traditional textbook direction, to having timber oriented goals with an increasing emphasis on advances in science, and finally to having broader forest oriented goals (including timber) with science based management directions.

The other major change to the guides over the years has been the move from being purely silviculture-based (i.e., focussing on the art and science of growing trees), to a silviculture/management mix – where arguably the management side (i.e., what techniques are recommended to be used on specific sites) has taken the dominant role.

The first series of silvicultural guides in Ontario were published in the 1970s. They were intended to help forest managers appropriately renew and manage harvested stands on their forest units.

The first series of silvicultural guides covered the important tree species in the province including:

The primary objective of these guides was to provide direction that would result in a continuous flow of raw materials for the saw and pulp mills across the province. Direction in each guide was built on established, traditional management approaches, with some limited local management experiences. The guides also identified aesthetics and site protection as 2 secondary objectives.

Each guide included a description of the silvics of the species, management alternatives (with some limited references to site and featured wildlife species), damaging agents, and minimum stocking standards. Each was written by head office staff – all based in Toronto, with limited input from field researchers or practitioners.

While these Guides brought together a range of information, a concern with these guides was that in many cases they described past operational practices that may or may not have had success in Ontario, rather than focus on the best currently available knowledge provided by recent scientific studies and management trials. It was also not mandatory to use any of these guides in the development of Timber Management Plans. They were available, and some plans used them, but incorporating their direction into management decision was left to local discretion.

The decision to include a guide for the aspen working group was a surprising choice. Up to that time aspen was generally seen as a weed species. But, expected increases in demand for wood fibre along with the vast volumes of aspen across the province, primarily in the north, made it an increasingly important species. At this time the province was also considering the use of hybrid poplar to address the increasing wood demands (Heeney 1972).

The original set of silvicultural guides were in place and used for approximately 15 years.

In the early 1980s a number of additional management guides were published in Ontario. While they weren’t officially tied to the initial set of silvicultural guides, they did provide additional information on specific species/areas within the province. This group include: A silvicultural guide for hybrid poplar (Barkley 1983), which built on Heeney’s earlier work (1972) and the work of the Brockville Fast Growing Hardwoods Group; an updated guide for managing tolerant hardwoods in Algonquin Park (OMNR, 1983), which built on the 1973 version with updated research results; and a guide to Managing red pine Plantations in southern Ontario (OMNR, 1986) based on the management approaches and trials done by many of the conservation authorities in southern Ontario. These additional guides brought together the best available science, including local research and field trial results, to provide management direction for the cover type in one document. But similar to the first set of silvicultural guides none were mandatory to use.

The “Class Environmental Assessment by the Ministry of Natural Resources for Timber Management on Crown Lands in Ontario” (Timber EA) (EAB 1994) became the key driver for the next set of silvicultural guides, and it remains the key driver that continues to influence guide development and use to the present day.

During the run up to Timber EA hearings, and during the actual hearings themselves (1988-1992), there was pressure on the OMNR, to demonstrate that their policies for forest planning and operations were current and relevant. When the hearings began the existing set of silvicultural guides were more than 10 years old, and there were concerns that direction in those guides may not reflect the current state of scientific knowledge and monitoring results.

Also during this time a key focus for the OMNR, was the management of old-growth white and red pine in the Temagami area. The old-growth white and red pine issue focused the public’s attention on not only the need for appropriate silviculture in Crown forest, but also the inclusion of social concerns in the decision making process.

The second series of provincial silvicultural guides was produced in this environment, and included:

The volume on Jack pine (a species not included in the first series of silvicultural guides) was built primarily on the work presented at the Federal-Provincial Jack pine Symposium held in 1984 (Smith and Brown 1984). Jack pine had been utilized for saw-timber for quite some time, but it was only with it’s increased use in pulp mills that the need for more specific management direction evolved.

The initial draft of the Silvicultural Guide for the Tolerant Hardwoods working group was extremely long – more than 400 pages in length when other guides in this series were 100 pages or less. To deal with the “excessive” length, an agreement was made to include only the “strategic” portions in the silvicultural guide itself (making it similar to other volumes in this set), and to produce a companion tree marking guide (Anderson and Rice, 1993) which would describe the tactics of how to implement uneven-aged management direction in these forest types.

The irony to this decision was that tree marking was used in other forest types and silvicultural systems (e.g., pine shelterwoods), and managers of those forests wondered why a tree marking guide did not include all scenarios that required tree marking. This concern was addressed in a later revision.

By the time the Timber EA hearings ended in 1992, and the final report was tabled (EAB 1994), the new series of silvicultural guides were completed.

This second series of silvicultural guides, developed in the mid- to late-1980s went well beyond the guides that were created 15-years earlier. While they contained some of the same topics, including information on silvics, site conditions (including expanded references to ecosites and site conditions), management alternatives, damaging agents, and in some cases minimum stocking standards, they were developed and treated as new documents, and not as simply updates of the previous volumes. While the guides still maintained a timber focus, they also included a greater emphasis on other, broader forest considerations (e.g., wildlife and habitat).

Each guide was written by local experts for the specific working group (scientists, foresters, consultants), with a designated “lead author” (who wrote the majority of the material) and a supporting team. Head office staff provided oversight and some administrative support.

The second series of silvicultural guides were available for use for about a decade. With the second series of silvicultural guides and a tree marking guide in place, there were still some concerns around ensuring that partial harvest silvicultural systems were being implemented in a sustainable manner. These concerns led to the decision that tree marking on Crown stands in the Great Lakes-St Lawrence forest region needed to be done by certified tree markers. Tree marking certification began in 1993 using the tree marking guide (Anderson and Rice 1993) as the foundation for the certification course. Use of certified tree markers was engrained into the forest management system in the Great Lakes-St. Lawrence forests with its inclusion in the Forest Operations and Silviculture Manual (FOSM) in 1995.

Use of this second set of silvicultural guides was again not mandatory in management planning. It wasn’t until 1995, with the enactment of the Crown Forest Sustainability Act and the need to comply with the regulated Forest Operations and Silviculture Manual, that the use of provincial silvicultural guides became mandatory in forest management planning and operational activities.

In their decision report, the EA Board supported the use of guides (or what the Board called “implementation manuals”) to ensure that forest management operations would be based on silvicultural prescriptions developed with the most current science and knowledge available.

The EA Board report (EAB 1994) also embedded the use and maintenance of silvicultural guides in the Terms and Conditions of the original Timber Class EA. Specifically:

From these Term and Conditions, the time requirement to review (and potentially revise) each of the guides became legally binding.

In addition, to address the increasing amount of mixedwood conditions in the boreal forest, an additional term and condition required the development of an entirely new silvicultural guide:

The first guides of the post-Timber EA period were developed in the second half of the 1990s after the Timber EA board’s decision, with the new Boreal Mixedwood guide completed in 2003.

In recognition of the need for similar silvicultural information and guidance for tree species that grew south of the Area of the Undertaking, MNR also developed an additional silvicultural guide that addressed southern Ontario forests.

The third series of provincial silvicultural guides included:

Similar to the work done during the development of the second set of silvicultural guides a decade earlier, an updated tree marking guide (OMNR, 2004) was also produced. It included tree marking direction for all stands receiving selection and shelterwood management approaches in the Great Lakes-St Lawrence forest region. This included both tolerant hardwood and conifer stand conditions where tree marking was necessary, and thus addressed the concern previously raised around tree marking in pine shelterwood stands.

Needing to follow the direction provided in the Timber EA Board’s report and Term and Conditions, this series of silvicultural guides is distinctly different that the previous ones.

The key differences were:

The requirements put forth by the Timber EA decision changed the focus of this series of guides to ones that focused primarily on management options (i.e., what was recommended, conditionally recommended, or not recommended to do) as opposed to the more traditional silvicultural guides (i.e., detailing the art and science of growing trees).

The third series of guides was again written by a writing team of experts (scientists, foresters, consultants). While there was a writing team leader, each section was authored by a specialist of that area/discipline. As with previous series, there was oversight and administrative support from head office staff.

In 2000 the OMNR, hired a group of consultants (Arborvitae et al. 2000) to review the existing series of forest management guides (including not only the silviculture guides, but also guides dealing with wildlife, aquatics, disturbance patterns, physical environment, and roads). As part of their review, they addressed how well direction in the existing guides was integrated with other guides. This review met the Timber EA requirement for a 5-year review of silviculture guides. No changes to the silvicultural guides were recommended at that time.

In 2003, nine years after the Timber EA decision had been in place, a legally required review of the entire Timber EA decision (as outlined in Term and Condition 113 (a)) took place. This review included an assessment of how OMNR, had addressed all Terms and Conditions in the original Timber EA Board decision. This review was part of the process that led the EA Board to renew the approval to practice forest management on Crown lands in Ontario. That renewal request was approved in 2003.

With the approved renewal request, the Ministry of the Environment issued a Declaration Order (“Declaration Order Regarding MNR’s Class Environmental Assessment Approval for Forest Management on Crown Lands in Ontario”, 2003). The “Dec Order” renewed the approval to conduct forestry on Crown lands, and came with a set of Conditions – many similar to the original Timber EA’s Terms and Conditions. The need for guide review and revision is found in Dec Order Condition 38.

To meet the legal requirements of the Dec Order conditions, the black spruce, jack pine, and aspen guide, the tolerant hardwood guide, and the Great Lakes-St. Lawrence conifer guide were reviewed in 2005 (5 years after being part of the review of all forest management guides). The boreal mixedwood guide was reviewed in 2008 (5 years after its original approval). Reviews were based on the criteria listed in Dec Order Condition 38(d).

Since the southern Ontario silviculture guide addresses Crown forests outside of the Area of the Undertaking, it is not addressed by the Dec Order. Nonetheless, as part of good policy development, it, too, was reviewed in 2005, five years after its publication. That review followed the same review criteria as used for the other guides.

The recommendation from the 2005 and 2008 guide reviews, and supported by the Provincial Forest Technical Committee (PFTC), was to not revise the silvicultural guides immediately, but to wait until after the Landscape Guide and Stand and Site Guide were completed. This recommendation reflected the limited staff available to work on the various guides. Once the Landscape and Stand and Site guides neared completion, revisions to the silvicultural guides for the area of the undertaking (AOU) would begin.

It was also decided by OMNR, that until work on a new silvicultural guide was to begin, silvicultural science and research efforts needed to focus on knowledge synthesis and field trials that would advance our understanding in three contentious issues. Those being: Full tree harvesting on shallow sites in northwestern Ontario, thinning and pre-commercial thinning of jack pine and spruce stands, and silvicultural approaches to manage eastern white cedar in the boreal forest region. Results of that work would feed into the silvicultural guide revision process once it began.

The Landscape Guide for Great Lakes-St. Lawrence Forests (OMNR, 2010a) and the Stand and Site Guide (OMNR, 2010b) received final approval in March 2010. Approval for the Landscape Guide for Boreal Forests (OMNR 2014) was received in February 2014.

With the Great Lakes St-Lawrence Landscape Guide and the Stand and Site Guide approved, formal work on the revision of the silvicultural guides for the AOU began in 2010. The results of that revision are in this document today.

Finally, to meet the requirements of the December Order, a second 5-year review of the southern Ontario silvicultural guide was undertaken in 2010. The primary recommendation from that review was for a revision of the southern Ontario guide to take place, and to begin once work on the AOU silvicultural guide is completed.

Wish to acknowledge, and say thank you to the following individuals for their input and comments on this section: Harvey Anderson, Rob Arnup, David Chapeskie, and Joe Churcher.

Literature cited

Anderson, H.W., B.D. Batchelor, C.M. Corbett, A.S. Corlett, D.T. Deugo, C.F. Husk and W.R. Wilson. 1990. A silvicultural guide for the tolerant hardwoods working group in Ontario. Science and Technology Series, Volume 7. Ontario Ministry of Natural Resources, Forest Resources Group. Queen’s Printer for Ontario. Sault Ste. Marie, ON. 178 pp.

Anderson, H.W. and J.A. Rice. 1993. A tree marking guide for the tolerant hardwoods working group in Ontario, Science and Technology Series, Volume 8. Ontario Ministry of Natural Resources, Forest Resources Group. Queen’s Printer for Ontario. Sault Ste. Marie, ON. 227 pp.

Arborvitae Environmental Services Ltd., Callaghan & Associates Inc., and CMC Ecological Consulting. 2000. Review of Forest Management Guides. Consultant’s report to the Provincial Forest Technical Committee. 294 pp.

Arnup, R.W., Campbell, B.A., Raper, R.P., Squires, M.F., Virgo, K.D., Wearn, V.H. and White, R.G. 1988. A silvicultural guide for the spruce working group in Ontario. Science and Technology Series, Volume 4. Ont. Min. Nat. Resour., Queen’s Printer for Ontario, Toronto, Ontario. 100 pp.

Barkley, B. 1983. Silvicultural guide for hybrid poplar in Ontario. OMNR. Brockville. 35 pp.

Chapeskie, D.J., D.F. Galley, J.R. Mitchell, N.W. Quinn and H.H. Struik. 1989. A silvicultural guide for the white pine and red pine working groups in Ontario. Science and Technology Series, Volume 6. Ontario Ministry Natural Resources, Forest Resources Group. Queen’s Printer for Ontario. Toronto. 102 pp.

Davidson, R.W., Atkins, R.C., Fry, R.D., Racey, G.D. and Weingartner, D.H. 1988. A silvicultural guide for the poplar working group in Ontario. Science and Technology Series, Volume 5. Ont. Min. Nat. Resour., Forest Resources Group. Queen’s Printer for Ontario. Toronto, ON. 67 pp.

Environmental Assessment Board (EAB). 1994. Reasons for the decision and decision, Class Environmental Assessment for the Ministry of Natural Resources for Timber Management on Crown Lands in Ontario (EA-87-02). Queen’s Printer for Ontario. Toronto. 576 p.

Frank, Robert M. and John C. Bjorkbom. 1973. A silvicultural guide for spruce-fir in the northeast. General Technical Report NE-6. Upper Darby, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 29 pp.

Galloway, R. 1986. Jack pine working group. Ontario Ministry of Natural Resources. Silvicultural guide series. 40 pp.

Heeney, C.J. 1972. A silvicultural guide to hybrid poplar production. Ontario Department of Lands and Forests. Toronto. 16 pp., plus appendix.

Heeney, C.J. and D.S. Bruce. 1974. Silvicultural guide for the hard maple, yellow birch and hemlock working group. OMNR. Forest Resources Branch. Toronto. 65 pp.

Heeney, C., J. Kemperman, and G. Brown. 1975. Silvicultural guide to the aspen working group. OMNR, Forest Resources Branch, Toronto. 47 pp.

Kimmins, J.P. 1973. Forest ecology: the biological basis for the management of renewable forest resources. Forestry Chronicle 49(1): 25-30.

Newnham, R.M. FLC Reed and Associates Ltd. 1978. Forest management in Canada: Summary. Canadian Forestry Service, Environment Canada. Forest Management Institute. Ottawa. Info Rep FMR-X-104. 55 pp.

Ontario Department of Lands and Forests (ODLF). 1948. Manual of Timber Management. Toronto. Baptist Johnson, Printer to the King’s Most Excellent Majesty. 5 books. 303 pp.

OMNR. 1973a. Management of tolerant hardwoods in Algonquin Provincial Park. OMNR. For Management Branch. 84 pp.

OMNR. 1973b. Silvicultural guide to the white pine working group. OMNR, Forest Resources Branch, Toronto. 34 pp.

OMNR. 1983. Management of tolerant hardwoods in Algonquin Provincial Park. OMNR. Forest Resources Branch. 72 pp.

OMNR. 1986. Managing Red pine Plantations. OMNR. Queen’s Printer for Ontario. Toronto. 134 pp.

OMNR. 1997. Silvicultural guide to managing for black spruce, jack pine and aspen on boreal forest ecosites in Ontario. Version 1.1. Ont. Min. Nat. Resour., Queen’s Printer for Ontario, Toronto. 3 books. 822 pp.

OMNR. 1998a. A silvicultural guide for the tolerant hardwood forest in Ontario. Ont. Min. Nat. Resour. Queen’s Printer for Ontario. Toronto. 500p.

OMNR. 1998b. A silvicultural guide for the Great Lakes-St. Lawrence conifer forest in Ontario. Ont. Min. Nat. Resour. Queen’s Printer for Ontario. Toronto. 424 pp.

OMNR. 2000. Silvicultural guide to managing southern Ontario forests, Ont. Min. Nat. Resour. Queen’s Printer for Ontario. Toronto. 654 pp.

OMNR. 2003. Silvicultural guide to managing spruce, fir, birch, and aspen mixedwoods in Ontario’s boreal forest. Version 1.0. Ont. Min. Nat. Resour., Queen’s Printer for Ontario. 382 pp.

OMNR. 2004. Ontario tree marking guide, Version 1.1. Ont. Min. Nat. Resour. Queen’s Printer for Ontario. Toronto. 252 pp.

OMNR. 2010a. Forest management guide for Great Lakes-St. Lawrence landscapes. Toronto. Queen’s Printer for Ontario. 57 pp.

OMNR. 2010b. Forest management guide for conserving biodiversity at the stand and site scales. Toronto. Queen’s Printer for Ontario. 211 pp.

Robinson, F.C. 1974. Silvicultural guide for the spruce working group. OMNR, Forest Resources Branch, Toronto. 43 pp.

Smith, C.R. and G. Brown <co-chairmen>. 1984. Jack Pine Symposium Proceedings, COJFRC Symposium Proceedings O-P-12, CFS Catalogue Number: Fo18-3/12-1984E, Sault Ste. Marie, ON. 195 pp.

Steneker, G.A. 1976. Guide to the silvicultural management of trembling aspen in the prairie provinces. Canadian Forestry Service, Northern Forest Research Centre, Edmonton, Alberta. Information Report NOR-X-164. 6pp.

Appendix 2 – Ecological land classification and silviculture

Prepared by Peter Uhlig [with minor edits]

Sustainable resource management requires maintenance of ecosystem components, their functions and supporting processes. To be sustainable, silvicultural activities and technologies must be applied within the bounds of ecosystem capacity and resilience. Central to defining these bounds is an understanding of the range of ecosystem responses to management practices (Hills 1961, Bailey 1996; Uhlig and Jordan 1994). Ecosystem classification is a critical tool to this end.

An ecosystem classification delineates areas of similar ecology at different nested—or hierarchical—levels, providing an effective framework for organizing knowledge of important ecosystem features, spatial patterns and interactions (Figure 1). Classifying ecosystems allows for better description, greater understanding of controlling processes, efficient inventory, communication, and hence management.

Both abiotic and biotic factors are used to classify ecosystems into units that are ecologically-meaningful (Hills 1961, Rowe and Sheard 1981, Bailey 1996). Units within a class have similar composition and structure, and share similar ecological processes such as growth and succession. The hierarchical structure of an ecosystem classification facilitates planning and management at different scales, from coarse level suitable for strategic planning (ecoregions and districts), through to a fine levels (ecosite, substrate and vegetation types), ideal for site-level interpretation (Rowe 1980).

Ecosystem classification, together with inventory and management interpretations, provide the fundamental information framework essential to the planning, management, monitoring and evaluation for all of Ontario’s forest resources. Ranging from ecoregional reporting on state of the resources, policy, resource planning, site-level management decision support, growth and yield evaluation, successional projections, effectiveness monitoring and accountability at national/provincial scales.

Ontario’s ecosystem classification program (ELC)

While ecosystem classification spans many scales and provides numerous information products the level most pertinent to the majority of forest management concerns is the Ecosite level. Ecosites are landscape areas consisting of typical, recurring associations of Vegetation Types (v-type) and Substrate Types (s-type) combinations within a context of repeating toposequence, landform and catenary sequences.

Ecosites are, first and foremost, based on the stable features of the physical landscape (substrate depth, texture, landform and nutrient regimes). Ecosite polygons are identified and delineated using those features of the environment which most affects the distribution and character of the vegetation, including substrate formation or depositional types (e.g. rock, organic, frozen, active, flooded), along with the substrate depth, texture, slope, and moisture. These physical features make up the “ecological domains”, or the ecological drivers, which direct the establishment and growth of vegetation, or community assembly. The delineation of the polygon is finally determined by the varying character of the vegetation, which is responding to not only the physical environment, but disturbance and succession as well. Since different vegetation communities can exist on similar environmental features, vegetation characteristics like treed, shrub, herbaceous, coniferous, deciduous (to name a few) are used as the basis to further distinguish and delineate polygons. Figure 2 provides a graphic depiction of the various scales influencing ecosite classification.

With their fundamental characteristics of substrate and vegetation characteristics, and hence site-level biological legacies, they also form a suitable information framework to assist with the understanding of vegetation changes over time, succession, establishment and competition.

Ecosites are spatial units to facilitate major corporate and partner ecological inventory, monitoring and assessment programs in support of operational planning, natural heritage planning and various program deliveries. Ecosites will provide the framework for operational planning of forests, wetlands, wildlife habitat, and natural heritage applications. In addition, ecosites may become the corporate inventory classes that MNR will be delivering through automated mapping processes that are critical to mapping ecosystems for watershed and other jurisdictional and local planning. Figure 3 provides an example inventory product, ecosite classification, and photograph of ground conditions.

An ecosystem classification can be re-interpreted through class aggregations for a variety of applications pertinent to silviculture. The results are most effective when coupled with an explicit, spatial inventory such as the first frame of figure 3. The re-interpretation and aggregation is typically customized to the specific question or application. For example if a forest manager was interested in forecasting the anticipated amount of competition following harvest, they would consider both direct site attributes (e.g. texture, moisture regime, depth, etc.) as well as current vegetation (e.g. indicator species, open versus closed canopy, etc.), both of which can be interpreted from ecosite information.

Substrates provide a stable representation of key factors supporting forest growth and play a critical role in the definition and recognition of ecosites. There are many ways to describe and quantify the substrate. Ecosites are ordered primarily by depth, texture, chemistry and moisture regime. Gradients of moisture and nutrients are particularly useful summaries of the combined influence of many substrate characteristics (depth, texture, parent material, landform, slope position, etc.). Combining these two conceptual scales into a single diagram provides a full edatopic grid which can be used to examine species and ecosite distribution in a broad and relevant environmental space. The resulting diagrams (immediately below this text) portray, for general silvicultural interpretation, the growing domain for each species of interest to this guide.

The nutrient regime classification used in the edatope diagrams was drawn from well developed applications in B.C. and Alberta using specific soil morphological features quantified in terms of soil nutrient chemical characteristics (Figure 5)

Figure 5 - Nutrient regime classification used to develop the edatope diagrams

The moisture regime classification follows that originally defined by Hills in 1959. Moisture regime expresses the long-term growing season availability for plant growth with a scale ranging from Dry (theta) through to wet (9).

To define the nutrient/moisture domain of each species, province-wide plot data networks supporting the ELC (Figure 6) were interrogated in conjunction with the ecosite level of classification to examine the affinities and prevalence of species across moisture and nutrient gradients. In general, a threshold of 20% occupancy was used for common species, and individually adjusted for less common species. Where data was limited, species-site relationships from other published sources were used as an additional source of information. The resulting domain therefore is neither an inclusive domain of all edaphic conditions where that species would occur, nor an ideal domain where growth or management success would be optimized. Rather, it is a generalized domain where the bulk of observations of that species occur.

The following pages present edatopes for individual species using common abbreviated species codes that can be translated as follows:

Appendix 3 - Factsheet by species

Black Ash (Fraxinus nigra)

Range

Habitat

Soil and site relations

Commonly grows in rich, moist to wet, fine textured mineral or organic soils in swamps, poorly drained depressions and riparian areas.

Associated forest cover

Most commonly found in small, isolated, pure stands in lowland hardwood swamps and less frequently mixed with balsam fir, trembling aspen, white birch, white spruce, cedar, red ash, red maple, and American elm.

Associated ecosites

Black ash may exist in the canopy in the following ecosites: 28, 56, 71, 89, 105, 120, 129, 224, 130, 131

Reproduction

Growth

Damaging agents

Insects

Emerald ash borer is an invasive insect causing decline and rapid mortality by feeding on cambium and girdling tree. Oystershell scale is an insect that feeds on twigs, branches and foliage and may occasionally kill trees in small isolated clumps.

Diseases

Trees greater than 100 years old are susceptible to stem and butt rot resulting most often in stem stain and not decay.

Wildlife

Deer feed on young seedlings where alternate preferred browse is scarce. Beavers occasionally cut down black ash for construction material.

Other

Road construction and harvesting can alter hydrological flow and water stagnation in stands which adversely impacts growth and survival. Due to shallow rooting system, trees on wet soils are susceptible to windthrow.

Genetics

Races, varieties, hybridization

No known races or hybrids of black ash.

Seed transfer considerations

No genetic information is available. Local seed is therefore the safest bet.

Genetic resource management

As a result of the emerald ash borer, there are initiatives to conserve large populations across their range, retain and increase the diversity and regeneration potential within each population, and observe and archive trees which demonstrate tolerance.

Tolerances

Light

Young black ash intermediate in shade tolerance but tolerance weakens with age. Regeneration probably grow best in 45 - 50% full sunlight.

Temperature

Young suckers resistant to frost; resistance of seedlings is unknown.

Moisture

Very tolerant of frequent, well-aerated flooding for periods of up to several weeks. Capable of quickly growing new roots after flooding. Sprouts are more flood-tolerant than seedlings.

Low nutrient conditions

Low tolerance to low nutrient conditions

Response to disturbance

Overstory removal

Moderately elastic. In mature stands, seedlings and sprouts grow best in stand openings greater than 0.5 ha in size. Advanced regeneration is minimal under a fully closed canopy.

Fire

Fire hazard rating is low due to wet conditions of sites typically occupied by pure stands.

Competition

Shrub and grass control is required to ensure survival during the establishment phase. Black ash seedlings grow more quickly than American elm and red maple on disturbed mineral soils with a high water table or impeded drainage.

Management

Low-felled stumps typically produce 7-17 sprouts that grow more vigourously than seedlings. Thinnings are recommended for trees younger than 110 years of age.

White ash (Fraxinus americana)

Range

Habitat

Soil and site relations

Usually occurs on deep, well-drained, upland soils, mixed with other broadleaf trees and occasional conifers.

Associated forest cover

White ash is found in mixed forests and is never a dominant species. Its primary associates are eastern white pine, red oak, sugar maple, red maple, yellow birch, beech, black cherry and hemlock.

Associated ecosites

White ash may exist in the canopy in the following ecosites: 56, 71, 89, 105, 120

Reproduction

Growth

Damaging agents

Insects

The exotic invasive emerald ash borer is causing widespread mortality of healthy ash in many areas of Ontario.

Emerald ash borer
Dan Rowlinson

Diseases

Seedlings are susceptible to leaf spot and anthracnose.

Wildlife

Ash is easily damaged by browsing but is one of the less preferred deer browse species. Bark is consumed by rabbits, beaver, porcupine, mices and voles.

Other

Ash periodically undergoes declines; the trees exhibit a progressive dieback called “ash yellows”; these declines are probably triggered by climate induced stress, which prediposes them to other damaging agents.

Genetics

Races, varieties, hybridization

Hybridization with other ash species is extremely rare.

Genetic resource management

As a result of the emerald ash borer, there are initiatives to conserve large populations across their range, retain and increase the diversity and regeneration potential within each population, and observe and archive trees which demonstrate tolerance.

Seed transfer considerations

Tree stem dieback caused by fall frost injury is significantly correlated to latitude of seed origin. Local and northern seed sources suffer the least from fall frost and show significantly better survival and growth than southern seed sources at northern planting sites.

Tolerances

Light

Although mature white ash is classified as shade intolerant, the seedlings are shade tolerant. A seedling can survive at less than 3% full sunlight for a few years.

Temperature

White ash varies in cold hardiness with the latitude of origin. Trees grown in the north have a lower lethal temperatures than those from the south.

Moisture

Is found growing on dry to moist sites and is intermediately tolerant of temporary flooding.

Low nutrient conditions

Low tolerance to low nutrient conditions

Response to disturbance

Overstory removal

Young stands (5 to 10 years) respond to thinning by increasing height growth but older stands (35 to 85) do not exhibit increased growth from release.

Fire

White ash bark is not fire resistant but resprouts from the root crown after fire.

Competition

Commonly invades old fields and grows rapidly. Seedlings can also survive under a canopy but grow very little until a canopy opening becomes available and then they can respond quickly.

Management

White ash responds well to shelterwood cutting. Advanced regeneration grows best with 60 percent of the overstory removed.

Basswood (Tilia americana)

Range

Habitat

Soil and site relations

Commonly occurs on moist slopes that face north or east. Obtains maximum development on finer-textured soils such as sandy loam, loam and silt loam, but also found on sand dunes and dry exposed rock ridges.

Associated forest cover

Found in mixed stands with other broadleaf trees such as sugar maple, American beech, white ash and red oak.

Associated ecosites