Species at Risk


Butternut  (Juglans cinerea)

Status in Canada: Endangered

Status in Ontario: Endangered

Status at SWCR: Uncommon

Butternut is a small to medium size tree that generally grows alone or in small groups within a range of deciduous and mixed forests.

Quick Facts:

  • It is affected by many different exotic diseases and pests. The combination of these makes it very hard for butternut trees to grow and thrive.
  • It loves sun, and can usually be found along fencerows and at the edges of fields.
  • It is in the walnut family, and hybridizes with exotic, ornamental walnut trees introduced to the area.
  • Like other walnut species, it secretes a chemical from its roots (juglone) that can kill other plants growing nearby.

Threats at the St. Williams Conservation Reserve:

Butternut Canker and other exotic diseases and pests: Butternut is being severely decimated across its northeastern North American range by a non-native fungus that causes Butternut canker. Other exotic diseases (such as leaf spot, butternut curculio, fall webworm, Bunch-broom disease, etc.) affect butternut trees and make it more vulnerable to Butternut canker.

Hybridization: Butternuts in Ontario have been hybridizing with exotic walnut (Juglans) species.

Lack of regeneration: Seed collecting and predation, from overabundant natural predators and collecting by humans, is affecting the species’ ability to replace the trees dying from butternut canker.

Activities that can harm Butternut trees include:

  1. Illegal collecting of butternut seeds.
  2. Off-trail recreational activities that can trample seedlings, or remove them from their habitat, such as trampling, crushing under vehicles, and collecting.

St. Williams Conservation Reserve management practices:

  • Population monitoring
  • Forest thinning activities
  • 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