The American chestnut tree, long celebrated for its cabinet-grade wood, its meaty nuts and its widespread branches that shaded Longfellow's village smithy, was struck by a deadly blight in 1902, and by the end of World War II had disappeared from the country's forests.
From Maine to Florida, some 4 billion chestnut trees fell victim, a loss that in some areas took out one-quarter of the forest and devastated people's livelihoods and the local culture.
Now, however, in an effort to bring the American chestnut tree back into the U.S. landscape, the U.S. Forest Service has teamed with a group called the American Chestnut Foundation to develop a disease-resistant tree.
Researchers with the foundation have been crossbreeding the American variety with a resistant "Potentially, this is the greatest restoration effort that has ever been undertaken," said Rex Mann, a biologist for the U.S. Forest Service and founder of the Kentucky chapter of the American Chestnut Foundation.
In addition, what success comes from the chestnut effort could be used to save other species at risk.
The American butternut, the American beech, the white walnut, the dogwood, the eastern hemlock -- all are facing similar threats, Mann said.
Like the chestnut, many of these trees have relatives in Asia that are resistant to the pests and diseases that threaten them. If the chestnut program works, it could serve as a prototype for future restoration efforts should another disease sweep through forests as the chestnut blight did.
"The importance of what we're doing with chestnuts is in showing that we do have the ability to bring some of these species back," Mann said, "otherwise we're going to lose much of the diversity we've got."
Before the blight hit, chestnuts were an extremely important species in America, both to animals and humans. The trees produced a reliable crop of nuts year after year, in part because it flowered in June, well after the threat of frost damage.
"Everything that lived in the woods ate chestnuts," Mann said, including grouse, blue jays, turkeys, white-tailed deer, black bears and squirrels.
People who lived in flatlands tended to farm and didn't depend so much on the chestnut, but those who lived in the steep slopes of the Appalachians relied heavily on the tree. They sent their animals out to feed on fallen chestnuts every fall, and people used its wood for everything from cradles to coffins.
When the chestnut blight arrived during the early 1900s, its spores blew from tree to tree and settled on the chestnut's bark. From there it spread into an orange fuzz and caused cankers, or large wounds of dead wood. A tree could survive the fungal infestation for a time, until it reached the layer of tree just under the bark where new wood formation takes place.
Once that happened, the tree withered and died, so that only its roots, protected by the soil, were left. The root balls of thousands of chestnuts are still alive underground in eastern forests, but whenever a new shoot comes up, after a few months or years it succumbs to the blight and disappears again.
The chestnut restoration program is unusual in that for the first time scientists are taking methodologies developed for crops and applying them to a forest species, said Fred Hebard, the lead scientist in charge of the American Chestnut Foundation's tree farm in Meadowview, Va.
To breed the new tree, Hebard and colleagues chose a resistant Chinese chestnut and hand-pollinated a surviving American chestnut tree. The Chinese have carefully cultivated their chestnut trees for over 2,000 years to produce larger nuts, about the size of golf ball.
Chinese trees themselves are smaller than the American variety, have more branches and look something like an apple tree, Hebard said. American chestnut trees, on the other hand, are adapted to forest conditions, with wide, straight trunks that can reach up to 100 feet tall to get to the light. And its nuts are smaller, about the size and shape of a flattened cherry.
After the first generation of half-Chinese, half-American trees came of age, the pollen was collected and used to fertilize another American chestnut tree, leading to offspring with half of its genes from the resistant Chinese tree and half from its American cousin.
Those trees were then tested for their resistance to the blight. Whichever ones proved the most hardy were then selected to crossbreed again with an American chestnut. The process has been repeated through seven generations, and seeds from the final crop will be available for a test planting next spring.
The idea is to wind up with a resistant tree with American chestnut characteristics that will allow it to survive and reproduce under forest conditions.
The American chestnut is not a fast-growing species. Trees are long-lived and the vision for restoration is long term, with planners looking decades into the future.
In one community in Kentucky, schoolchildren and grandparents are working together to help with the chestnut breeding program. They go out to find surviving American chestnut trees so they can be bred with the new resistant trees.
"We've got the older people and the children working together to bring them back," said Bob Cornett, a grandparent and retired government official in Georgetown, Ky. "This is not just cutesy-pie kind of stuff, because the children are needed for this. The adults know that the children will have to do the follow through, because the older people will be gone."
"Everyone knows this is a natural partnership between the generations," he said.The Ledger (Florida)
