Randy Nonemacher - The American Chestnut Foundation
In addition to the tree’s strong wood being used for barns, shingles and telephone poles, the tree’s nuts sustained forest animals and were sold throughout Appalachia. They were lauded in Mel Torme’s “The Christmas Song,” and Henry David Thoreau frequently wrote about hunting for autumn chestnuts in the forests surrounding Walden Pond.
“It was a cornerstone species,” said Stacy Clark, a research forester for the U.S. Forest Service. “It was probably the most versatile tree in the woods.” The American chestnut tree, which has saw-teeth-edged leaves, shouldn’t be confused with horse- or buckeye-chestnut trees, which come from separate tree families and produce inedible nuts.
The Asian fungus that crippled the species was first detected in New York’s Bronx Zoo in 1904. The disease starved the tree of water and nutrients and spread rapidly despite a quarantine effort. By 1940, billions of trees had died. “I don’t think there’s been anything nearly as extensive as the chestnut blight,” said Thomas Holmes, a Forest Service researcher.
American elms also have suffered from a blight triggered by Dutch elm disease, a fungus spread by beetles and first detected in the U.S. in the 1920s. Scientists have had some success in selecting varieties of elms that are resistant to the disease, including the Princeton Elm. Beginning in 2005, the varieties have been planted across the country to assess for the best resistance.
Attempts to restore the American chestnut began in the 1930s, when scientists unsuccessfully tried to breed the tree with a Chinese variety that was immune to the fungus. Federal funding dried up by the 1960s.
The efforts were picked up again in the 1980s by scientists and plant lovers who founded the American Chestnut
|THE FIRST ENEMY OF AMERICAN CHESTNUT
In the early to mid-1800s, the American chestnut got its first shock from Phytophthora cinnamomi, an exotic rootborne fungus. Called ink disease because it turns roots black, P. cinnamomi reduced the range of the American chestnut by eliminating it from lower elevations. The disease causes root rot and persists in wet clay or compacted soils. Globally, P. cinnamomi causes economic and ecologic damage to forest, ornamental, and crop trees, including avocado and walnut.
According to U.S. Forest Service Southern Research Station research forester Stacy Clark, one question being posed in nursery production of chestnut seedlings relates to the best fertilization and irrigation protocols to limit the growth of fungal pathogens such as ink disease. Field studies have shown that American chestnut seedlings planted in soils contaminated with P. cinnamomi have little to no chance of survival.
Sidebar reprinted from Compass Magazine, U.S. Forest Service, Southern Research Station, 2008.
Foundation. They applied a new method, called backcross breeding, which was first used for corn that imparts preferable traits over several generations.
The foundation started planting their new chestnuts—onesixteenth Chinese and the rest American — in Virginia in 2006. More than 100,000 of the trees are growing across 19 states,