Endangered Species: The American chestnut
Tuesday, September 24, 2013, 8:32 AM
Prior to the 20th century, experts estimate there were 16 billion American chestnuts in Canada and the U.S., and the tree was a big driver of the economy on both sides of the border.
This is a hardy species that's largely unaffected by frost, in addition to being rot-resistant. As a result its wood has been used in the production of fences, barns, homes and barns.
It also provided food for wildlife and livestock.
During the first half of the 20th century, a devastating fungal disease was accidentally introduced into the North American ecosystem through imported Japanese chestnut trees. The air-borne pathogen enters trees through bark punctures, cutting off the flow of nutrients and eventually killing the tree.
It's highly effective, wiping out 99% of American chestnuts within a few short decades.
Many of the trees that have survived appear to be resistant to the blight. Experts are in the process of scouring the ecosystem, in search of trees that can be used to re-propagate the species.
"There’s been a variety of starts," says Tys Theysmeyer, Head of Natural Lands at the Royal Botanical Gardens in Burlington, Ontario.
"Our goal [at the RBG] is to find of-Ontario American chestnut trees that can resist the fungus. Right now throughout the province of Ontario and at the RBG we have found a couple of trees that actually fall into this category, but the challenge is in recognizing the trees that are actually American chestnuts, and not Chinese chestnuts. Most people actually can't recognize the American chestnut because they’re so rare, and other chestnuts have been brought to North America."
Members of the public who think they've come across an American chestnut tree are invited to send leaf and twig samples to the Royal Botanical Gardens -- but according to experts, more than 80% of leaves that are sent in for identification are either from Chinese chestnuts or Chinese/American hybrids, which are blight-resistant and -- though similar in appearance -- a completely different tree than the American chestnut.
HOW TO IDENTIFY AN AMERICAN CHESTNUT TREE
An American chestnut is best identified through its leaves.
[Image courtesy of the American Chestnut Foundation]
American chestnut leaves are large and straight with sharp teeth, unlike other chestnut trees, which tend to have smaller leaves and teeth that are small or scalloped.
A leaf comparison chart can be downloaded from the American Chestnut Foundation website.