Information about blowdown, a wind event affecting trees in Ontario.
- Severe weather events can cause pockets or large areas of forest to blowdown, which can result in some or all trees within an area to break off or uproot.
- Blowdown events in Ontario usually range from 5 to 50 hectares in size, but can get as large as 500,000 hectares, particularly in the boreal forests of northern Ontario.
- Other terms used include: windthrow, windblow and stem breakage.
- Some blowdown events level most or all of the trees in a stand, with the trees lying in the same direction on the ground.
- This is common in spruce and jack pine stands in the boreal forest.
- In poplar or mixed-wood stands, often only tops or portions of trees are damaged, breaking off near the crown.
- Areas of blowdown become a fire hazard as the dead trees dry out.
- Blowdown is often caused by a straight-lined wind storm that is referred to as a “derecho”.
- The 2005 blowdown near Lac Seul in northwest Ontario was over half a million hectares in size.
Updated: July 28, 2022
Published: July 18, 2014