An excellent update on the work being done to save the American chestnuts. The Charlotte Observer has the story:
MEADOWVIEW, VA. –The Mighty Giants ruled the Appalachian forests until their tragic and costly demise in first half of the 20th century.
An Asian blight, discovered in New York in 1904, swept relentlessly through stand after stand of American chestnuts, killing an estimated four billion trees from Maine to Mississippi, including the western Carolinas.The massive chestnuts supplied rot-resistant logs for cabins and barns; provided easy-to-work wood for cradles and coffins, fence posts and furniture; yielded bark tannin for tanning leather; produced nuts for food and income and forage for black bears, wild turkeys and other wildlife.
Now, a 19-year-old private program to resurrect the Mighty Giants by breeding trees to resist the deadly blight will reach a milestone in 2009. That’s when the first seedlings will be planted outside of orchards, on national forest land in Virginia.
Scientists for decades have been trying to create a tree that will survive the blight, an airborne fungus. A federal effort ended in 1960 without success. In 1983, a group of plant scientists formed the American Chestnut Foundation with a goal to restore the chestnut as a wild forest tree.
Beginning in 1989, under the direction of Dr. Fred Hebard, staff pathologist, the foundation began a long-term breeding program at its Meadowview Research Farms in southwestern Virginia. The program relies on the Chinese chestnut, which is resistant to the blight. The farms now have nearly 34,000 trees of various parentages and ages in orchards. The trees carry blight-resistance genes from Chinese trees and genes from more than 500 American trees.
Breeding began with half-Chinese, half-American hybrids. Hebard and his staff “backcrossed” three generations with American trees. That dilutes out unwanted Chinese characteristics (it grows into the shape of an apple tree) and retains American traits (the forest tree grew to 100 feet).
Sometimes undesirable genes prevail. On a recent tour of the farms, Hebard pointed out a blighted half-Chinese, half-American tree. “It’s blight stricken because it’s got susceptibility genes,” he said, from its American parent. Hebard eliminates blight vulnerability by intercrossing the fourth generation trees with each other for two more generations. That lets offspring inherit only resistance genes.
The resulting sixth-generation trees consist of 94 percent American and 6 percent Chinese genes, which should make them highly resistant to the blight.