More than 50 years after nearly being wiped out in eastern U.S. forests by a deadly imported fungus, the American chestnut may be on the comeback trail.
American Chestnut Foundation scientists say they have bred the U.S. tree with a blight-resistant Asian chestnut to produce a hardy variety that retains about 94 percent of its original genes.
The foundation and its partners, the U.S. Forest Service and the University of Tennessee, announced last week that the first-ever crops of blight-resistant saplings are thriving after their first growing season in three national forests.
"The successful plantings are another step in the effort to reintroduce this keystone species back into its native range," said Roger Williams, the service's director of forest management for the Southern Region.
"The American chestnut is important because it was once an integral part of the Appalachian culture, providing food for wildlife and contributing to the diversity of the forest ecosystem," Williams added.
A recent study also suggests that the tree's rapid growth rate makes it one of the best sponges for greenhouse gases. Purdue University professor Douglass Jacobs' work suggests that the tree's superior carbon capacity makes it an ideal candidate for forest restoration projects and carbon-offset schemes, particularly on marginal farmland in the Midwest (Greenwire, July 1).
The chestnuts planted last year in national forests in North Carolina, Tennessee and Virginia are the first of the blight-resistant variety to be grown in natural forest settings. About 1,200 were planted in undisclosed locations, 500 of which were engineered to resist the fungus.
At two years old, the trees stand between 4 and 6 feet tall and appear virtually identical to the purebred variety, said Bryan Burhans, CEO of the chestnut foundation, which is based in Asheville, N.C. While scientists are confident the trees will survive exposure to the fungus, they won't know for sure until at least five or 10 years, he said.
But blight is not the only threat facing the new chestnuts. Although the new trees share 15/16 of their ancestors' genes, it is unclear how well they will be able to compete with the native forest species.
"Genes don't act like light switches," Burhans said. Instead, they interact in ways science is only beginning to understand, he said.
The foundation has plans to plant an additional 1,200 trees in national forests in the South beginning next year.
The Forest Service has launched a Web site with photos of the chestnuts' recent growth and videos of the monitoring process.