Species at Risk

American Chestnut

American Chestnut (Castanea dentata)

American Chestnut nuts (mg)

Status in Canada: Endangered

Status in Ontario: Endangered

Status at SWCR: Common

The American Chestnut was formerly one of the dominant tree species in many forests in southern Ontario but this imposing tree is all but gone due to a disease called the Chestnut Blight.

Quick Facts:

  • It used to grow up to 30m tall, and have trunks up to 1.5m in diameter!
  • Chestnut trees can’t fertilize themselves, and surviving trees are now so isolated that cross-pollination is very difficult: as more trees die from Chestnut blight, it gets harder and harder for surviving populations to reproduce.
  • It is not related to the European Horse Chestnut (Aesculus hippocastanum), which is commonly planted as an ornamental tree in Ontario.

Threats at the St. Williams Conservation Reserve:

Chestnut Blight: this invasive fungus kills trees and isolates survivors, decimating populations, and making it hard for them to reproduce.

Seed predation: seeds are rare to begin with, and they are often eaten by native animals such as squirrels and deer.

Loss of Individuals: Large trees are killed during forest harvesting and development.

Hybridization: American Chestnut will hybridize with introduced chestnut species.

Activities that can damage Chestnut trees and their habitat include:

  1. Activities that interfere with understory shrubs, unauthorized plant collecting and off-trail ATV use.
  2. Vegetation management activities that can crush or small trees and saplings, such as prescribed burns, herbicide use to control invasive plants, conifer plantation thinning.
  3. Off-trail recreational activities that can trample saplings, or remove them from their habitat, such as trampling, crushing under vehicles, and collecting.

St. Williams Conservation Reserve management practices:

  • Population monitoring
  • Enforcement of unauthorized trail use

What you can do to help:

  • Follow the code of conduct for recreational activities in the Conservation Reserve and know and respect the current trail-use regulations.
  • Report unauthorized trail use or any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).

More information:

Species At Risk Public Registry Profile

Ontario Species at Risk Profile

Funding for this project was provided through the Species At Risk Stewardship Fund