Trees in Trouble

Conserve Genetic Diversity of Trees in Trouble

Species at Risk

There are many reasons species become officially listed species at risk – either endangered, threatened or of concern. Threats include insects, diseases, habitat loss, and hybridization. In some cases more than one threat is at work. Other factors such as seed predation, poor harvest practices, natural rarity, and climate change effects can add to their vulnerability. There are also species that are in trouble though not yet officially listed.

More than 200 species of plants and animals are at risk of disappearing from Ontario.

Learn how a plant or animal is classified as endangered, threatened, special concern or extirpated. The Committee on the Status of Species at Risk in Ontario (COSSARO) oversees this work.


Butternut is a Threatened species. Learn about our shared roles to help recover the species. Learn more about Butternut


Emerald Ash Borer is devastating ash trees across Ontario and eastern North America. Learn more about Ash