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American Chestnut

American Chestnut
   Photo: ROM

Features: The American Chestnut (Castanea dentata) has all but disappeared from its former eastern North American range owing to an epidemic caused by a type of fungus called the Chestnut Blight (Cryphonectria parasitica). The Blight was probably imported into North America from Asia in the early 1900's. Formerly, this imposing tree grew to heights of 30 metres, and its edible nuts provided an important source of food for a variety of mammals and birds, in addition to being eaten by humans. Although some small trees and suckers from the roots of old trees continue to grow in isolated locations, it is unlikely that the American Chestnut will ever again play a dominant role in deciduous forest ecosystems. The common southeast European Horse Chestnut (Aesculus hippocastanum) is widely planted as an ornamental tree in cities and is not related to the American Chestnut.

Status: Endangered Provincially and Nationally

Range: The American Chestnut was widespread in eastern North America, from southern Ontario and adjacent Michigan, east to Maine and south to Alabama and Georgia. In Canada, it was restricted primarily to southwestern Ontario's Carolinian Forest Zone, where it was a relatively widespread and dominant species in some areas. Today, less than 200 trees of any size remain in the province.

Threats: The epidemic which followed the accidental introduction of the Chestnut Blight killed 99% of American Chestnut trees within about 30 years. The Blight remains a threat today, but some remaining trees are resistant to severe forms of the disease and a form of the Blight has evolved into a less deadly type.

Protection: Most of the surviving trees and suckers scattered over southern Ontario are on private land. A multi-disciplinary recovery team, formed in 1988, is conducting research to identify blight-resistant individuals, collecting fruit, and carrying out artificial pollination of flowering trees. The key to the recovery of this species may lie in the successful propagation and planting of disease-resistant stock.

The American Chestnut is listed as an endangered species under Ontario's Endangered Species Act, 2007. This Act protects the tree from being collected, killed, or harmed. The Natural Heritage component of the Provincial Policy Statement under Ontario's Planning Act provides for the protection of significant habitat of threatened species.

Text Sources: Ambrose 2004; Ambrose and Aboud 1987; Waldron 1997

Last Modified Date: October 2008

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