Volume 78/Number 4
Fall 1998

Tennessee Alumnus
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Hope for Chesnuts

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Digging and scratching with his pocket knife, he peels away the bark to expose the deadly orange fungus underneath. He has seen this parasite before in other American chestnut trees in the Southern Appalachians. And this tree, like the others, will wither and die.

Dr. Hill Craddock is in the Lula Lake Land Trust, a 2,100-acre forest preserve on the Georgia side of Lookout Mountain, where some of the mountain's last American chestnut trees cling to life. These trees are relics of a grand sweep of chestnuts that once covered the Appalachian range from New England to the deep South.

So swift and so deadly was the blight that killed them in the first half of the 20th century that scientists call it one of the worst ecological disasters in North America.

"We are talking about a pandemic in which every individual tree in the population was affected," says Craddock, a biologist at UT Chattanooga who has studied the trees here and abroad.

Using a combination of cross-breeding and biological control, Craddock is trying to develop a blight-resistant strain of chestnut tree that is tall enough to compete for sunlight in the rich forest canopy of the Southern Appalachians.

Though the splendor of the American chestnut faded long before he was born, Craddock, a baby boomer in John Lennon glasses, couldn't be more fascinated by the big trees. He grew his first one from a seed he planted when he was 15.

"They were the basis of an entire food chain," he says, "one of the most important of the mast-producing species."

Indeed, the trees were giants of the forest, reaching 100 feet tall and four feet wide.
The leaves were used for medicines, the wood for houses and tannin, and the nuts for food.

First noticed in New York in 1904, the fungus that killed them originated in Asia. It spread 25 to 30 miles a year and by 1950 had wiped out virtually every mature American chestnut in the tree's native range.

The fungus attacks the bark and works its way around the stem, choking the top part of the tree while leaving the roots intact. Most of the chestnut trees found in the woods today are shoots that have sprouted from the roots of older trees. They, too, will succumb to blight.

Last spring Craddock and a team of volunteers planted 200 American Chinese hybrids in a forest clearing at Lula Lake. The hybrids will be treated with a fungus-blocking virus and used for crossbreeding, each breeding further diluting the Chinese genes.

The idea is to combine the blight-resistant qualities of the smaller Chinese chestnut and the physical attributes of the taller American chestnut. Ultimately, Craddock wants a resilient tree that is as close as possible to a pure American chestnut.

The project is one of several under way around the country in cooperation with the American Chestnut Foundation in Burlington, Vermont.

"I don't believe these trees will replace the American chestnut, but we are partway there," Craddock says. "This is an intermediate step, a way to check our progress."

Reprinted from The Chattanooga Times

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