Appendices related to Part C to this guide

Appendix C1: Woodland evaluation of significance criteria

Upon completion of the records review and site investigation, applicants will have identified and mapped any areas which meet the definition of a woodland under the Regulation. Procedures for determining the significance of unevaluated woodlands identified in the records review and site investigation are outlined below.

Tree cover

To be significant, a woodland must meet minimum standards for tree cover. For the purposes of determining tree cover, the tree amount is based on the average per hectare across the entire woodland. Temporary reductions in tree coverage below the required amounts from harvesting, blowdown or other causes would not be considered to affect the significance of a woodland. Woodlands which meet the minimum standards for tree cover have the potential to be significant and must be evaluated using the evaluation criteria in this section.

The following are minimum standards for tree cover:

1. a tree crown cover of over 60% of the ground, determinable from aerial photography²⁴
2. a tree crown cover of over 10% of the ground, determinable from aerial photography, together with stem estimates²⁵ of:
   • 1,000 trees of any size per hectare
   • 750 trees measuring over 5 centimetres in diameter, per hectare
   • 500 trees measuring over 12 centimetres in diameter, per hectare
   • 250 trees measuring over 20 centimetres in diameter, per hectare

Evaluation criteria

This section provides direction for the criteria for evaluating the significance of woodlands. This direction provides flexibility to accommodate various levels of woodland cover across ecoregions 6E and 7E. These are the criteria as established by the MNR in accordance with the definition of significant woodland in the PPS. Woodlands that meet a minimum standard for any one of the criteria listed below are considered significant. This evaluation approach will avoid overlooking sites that are outstanding in terms of only 1 criterion.

This approach involves first assessing the conditions in the planning area to determine whether division into sub-units is appropriate (that is, certain parts of a municipality have a higher/lower percentage of woodland cover than other parts). The study would then consider the individual evaluation criteria and threshold values that are appropriate based on woodland cover to classify a woodland as significant.

In addition to the “woodland size” criterion shown below, it is important that the other criteria based on functions or characteristics in the identification of significant woodlands are also used. Such functions or characteristics assist in identifying significant woodlands that may not meet the simple size criterion. Some criteria information (for example, composition, diversity, age) to support the identification of significant woodlands may be obtained only by site inspection. In the absence of more complete information, the size threshold is to be reduced to include woodlands that otherwise would be missed. For example, where woodland cover is between about 16 and 30% of the land base, woodlands closer to 4 hectares, rather than 20 hectares, are to be considered significant. The size threshold and other criteria will need to be refined further with additional studies that may be undertaken during various stages of a planning process.

Each criteria contains a range of woodland size thresholds for significance based on the determination of the overall woodland cover. For example, the threshold for proximity to other woodlands or other habitats for a municipality with a woodland cover of less than 5% is 0.5 hectares. Woodlands that meet a minimum standard for any one of the criteria listed below are to be considered significant.

Note: The ELC definition for “forest” is based on 60% tree crown cover and includes first approximation codes FOD, FOM, FOC, CUP, SWD, SWM and SWC.

If undertaking on-ground stem estimates, all measurements of trees are to be taken at 1.37 metres from the ground. Trees regenerating on formerly non-treed fields should reach this height to be counted. Small trees in an area with some existing cover of larger trees (for example, savannahs) do not need to reach this height to be counted.

Minimum width

Further, to be considered significant, a woodland meeting a significance criterion must have an average minimum width of 40 metres measured to crown edges where the criterion size threshold is 0.5 to 4 hectares, and 60 metres where the criterion size threshold is 10 hectares or more.

Significant woodland evaluation criteria

1. Woodland size criterion

Size refers to the areal (spatial) extent of the woodland (irrespective of ownership), continuous even if intersected by narrow gaps 20 metres or less in width between crown edges.

Size value is related to the scarcity of woodland in the landscape derived on a municipal basis with consideration of differences in woodland coverage among physical sub-units (for example, watersheds, biophysical regions) and in landscape-level physiography (for example, moraines, clay plains).

Note: The size threshold should be reduced in the absence of information for the other 3 criteria. As a consideration in addressing the potential loss of biodiversity, the largest woodland in each lower-tier or single-tier municipality is considered significant.

2. Ecological functions criteria

(a) Woodland interior

Interior habitat is within the woodland more than 100 metres from the edge.

For purposes of this criterion, a maintained public road would create an edge even if the opening was not wider than 20 metres and did not create a separate woodland.

Woodlands are considered significant if they have an amount of interior habitat more than 100 metres from the edge:

(b) Proximity to other significant woodlands or habitats

Patches close to each other are of greater mutual benefit and value to wildlife.

Woodlands that overlap, abut or are close to other significant natural heritage features and areas are considered more valuable or significant than those that are not.

Woodlands are considered significant if a portion of the woodland is located within 30 metres from a significant natural feature or fish habitat and the entire woodland meets the area threshold:

(c) Linkages

Linkages are important connections providing for movement between habitats.

Woodlands that are located between other natural heritage features and areas can be important “stepping stones” for movement between habitats.

Woodlands are considered significant if they are located within a defined natural heritage system or provide a connecting link between 2 other significant features, each of which is within 120 metres, and the woodland meets the area threshold.

(d) Water protection

Source water protection is important. Natural hydrological processes should be maintained.

Woodlands are considered significant if they are located within 50 metres (or top of valley bank if greater) of a sensitive groundwater discharge, sensitive recharge, sensitive headwater area, watercourse or fish habitat and the woodland within this distance meets the minimum area threshold.

(e) Woodland diversity representation (composition)

Certain representative native woodland species have had major reductions in their natural distribution on the landscape in ecoregions 6E and 7E.

Woodlands are considered significant if they have:

• a naturally occurring (not planted) composition of native forest species that have declined significantly in ecoregions 6E and 7E and which meet the minimum area threshold, for example:

  • sugar maple
  • black maple
  • silver maple
  • red maple
  • yellow birch

  • hickory
  • beech
  • black ash
  • walnut
  • tamarack

  • spruce
  • pine
  • oak
  • basswood
  • hemlock
• a high native diversity through a combination of composition and terrain (for example, a woodland extending from hilltop to valley bottom to opposite slopes) and meets the minimum area threshold.

3. Uncommon characteristics criteria

Woodlands that are uncommon in terms of species composition, cover type, age or structure.

Older woodlands (that is, woodlands greater than 100 years old) are particularly valuable for several reasons including their contributions to genetic, species and ecosystem diversity.

Woodlands are considered significant if they have:

• a plant community with a provincial ranking of S1, S2 or S3 (as ranked by the natural heritage information centre [NHIC]) and are 0.5 hectares or more in size
• habitat (with 10 individual stems or 100 m² of leaf coverage) of a rare, uncommon or restricted woodland plant species (natural, not planted):
  • vascular plant species for which the coefficient of conservatism is 8, 9 or 10
  • tree species of restricted distribution such as sassafras or rock elm
  • species existing in only a limited number of sites within the planning area, and are 0.5 hectares or more in size
• characteristics of older woodlands or woodlands with larger tree size structure in native species:
  • older woodlands having 10 or more trees/ha greater than 100 years old
  • larger trees size structure: 10 or more trees/ha at least 50 centimetres in diameter, or a basal area of 8 or more m²/ha in trees that are at least 40 centimetres in diameter

Exceptions

Significant woodlands do not include a:

1. plantation managed for production of nursery stock
2. plantation managed for tree products with an average rotation of less than 20 years (for example, hybrid poplar or willow)
3. plantation established and continuously managed for the sole purpose of complete removal at rotation, without a forest restoration objective
4. woodland dominated by the invasive non-native tree species buckthorn (Rhamnus species) or Norway maple (Acer platanoides); if native tree species cover less than 10% of the ground and are represented by less than 100 stems of any size per hectare

Documentation and/or explanation must be included in the evaluation of significance report to demonstrate use of any of the above exceptions.