Back-Breeding Could Restore Chestnut Trees Ravaged by Blight

Lori Valigra
for National Geographic News
December 29, 2005

The American chestnut tree once dominated forests in Appalachia, until an Asian blight virtually killed off the species a century ago.

Now conservationists say they can restore the region's chestnut forests if scientists succeed in their efforts to breed new, blight-resistant strains of the tree.

"Entire communities in Appalachia depended on the chestnut for everything," said Marshal Case, president of the American Chestnut Foundation of Bennington, Vermont. The nonprofit has been leading the effort to reestablish the trees.

Chestnut trees were integral to everyday life in Appalachia, Case said, where they were called "cradle to grave" trees: Craftsmen made baby cradles and coffins from the rot-resistant hardwood. The trees were also used to build houses, telephone poles, and railroad ties.

Wildlife thrived on the trees, which each year produced bumper crops of nuts.

Then Chinese chestnut trees imported into the New York Botanical Gardens and Bronx Zoo carried the blight to the United States. The blight was first identified in 1904.

Within 50 years the blight fungus had infected and killed about 99.9 percent of the American chestnuts from Georgia to Maine and west to the Ohio Valley. "It moved fast, about 50 miles a year," Case added.

At least 50 strains of the fungus have been identified, and Chinese chestnut trees are resistant to all of them. The goal of the Chestnut Foundation is to breed that resistance into American trees.

To Case, the American tree is more majestic than the Chinese variety.

"American trees can grow to more than 120 feet [36.5 meters] tall," said Case. "The Chinese trees are much shorter and bushier."

Back-Breeding

The Chestnut Foundation is working with its 13 state chapters, the U.S. Forestry Service, and about 30 universities to reach its goal. So far the effort has produced a couple dozen trees on an experimental farm that are highly resistant to the blight fungus.

Continued on Next Page >>


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