The American Chestnut Tree is Making a Comeback
At the turn of the 20th century, the American Chestnut tree was ranked as one of the most important food sources for wildlife.
Every Christmas the sound of Nat King Cole crooning "Chestnuts roasting on an open fire…" resonates on the radio. However, for many the memory of roasting chestnuts is a distant one.
After the near extinction of the chestnut tree from Appalachian forests in the early 20th century, the trees are making a comeback in southeastern Ohio. The chestnut blight wiped out nearly all American chestnut trees in the eastern part of the country. As of 1932, they were extinct in Ohio. But the American Chestnut Foundation (ACF) is working to reintroduce this tree species to southeastern Ohio because of its environmental and historical importance, and source of food and lumber.
At one time, the American chestnut made up roughly 25 percent of trees in the forests of the eastern U.S. and about 5 percent of Ohio's forests. In 1904 the fungus Diaporthe parasitica was accidentally introduced to the Bronx Zoo in New York City through chestnut lumber imported from China. The parasitic fungus caused sores to develop in American chestnut trees, killing them slowly. By the early 1940s, the American chestnut was nearly extinct.
"In this case, extinct means that the canopy, the tops of the trees, die off down to the ground," said Brian McCarthy, professor of plant biology at Ohio University and president of the Ohio chapter of the ACF. "We can go into forests and find stumps of chestnut trees and even sprouts, but never a full tree."
Most trees produce a seed crop every three to four years through a process called masting, but the American chestnut produces a crop every year, which makes them a very important and consistent food for wildlife. The chestnut's plentiful seeds can also provide nutrition for animals. According to McCarthy, the trees were once the premiere food source of all major vertebrates in Appalachian Ohio forests. The blight, along with subsequent over hunting and the loss of habitat, caused deer, turkey and squirrel populations to plummet in Ohio forests by the 1930s.
The chestnut is referred to as the "Redwood of the East," McCarthy said. Like the giant California redwood trees, American chestnut trees are rot resistant. The chestnut's durability makes it a perfect tree to use for building barns and other structures.
The American Chestnut Foundation was founded in 1983 and has been working to create a blight-resistant chestnut hybrid that can once again grow successfully in the Eastern forests. McCarthy and other scientists are working toward that goal by using what McCarthy calls a classic breeding methodology.
By using the same genetic method bioengineers use to create shorter wheat or larger corn plants, scientists can create blight-resistant hybrids. They begin with blight-resistant Chinese chestnut trees and use the pollen from the American chestnut trees to create a hybrid that is then backcrossed, or mated, with another American chestnut tree to create a three-fourths American chestnut hybrid.
The breeding process is repeated until a tree is created that is fifteen-sixteenths American chestnut. It will then take 10 years for the trees to fully mature and for the scientists to know if the new tree strain is truly blight resistant, McCarthy explained.
The Appalachian Regional Reforestation Initiative (ARRI) is also planting the American chestnut on some of the 1.2 million acres of landscape that have been damaged from decades of coal mining. Chestnuts are one of the fastest-growing hardwood trees and are therefore ideal to test reforestation techniques at reclaimed mining sites such as those in Appalachia.
Although reintroducing the American chestnut would have ecological and economic benefits, the trees are also a valuable part of America's natural history. "There is also the whole natural heritage component," McCarthy said. "We want to have the value of bringing back the chestnut to restore the forests to their original condition."
Thousands of chestnut seedlings have already been planted by ARRI in partnership with ACF. Not only will that benefit the comeback of the chestnut, the plan also provides land owners with a renewable tree crop that they can harvest periodically.
For more information, visit www.acf.org.
This article was submitted by College Green, a new online publication run by students at Ohio University.
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