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Wildlife biologist Allison Cochran checks the growth of an American Chestnut tree that was planted by Alabama A&M researchers in a plot in the Bankhead National Forest.
Daily photo by Gary Lloyd
Wildlife biologist Allison Cochran checks the growth of an American Chestnut tree that was planted by Alabama A&M researchers in a plot in the Bankhead National Forest.

Return of the kings
Chestnut tree restoration
under way at Bankhead

By Kristen Bishop 340-2443

BANKHEAD NATIONAL FOREST — Researchers have planted hybrids at the Bankhead National Forest in an effort to restore the majestic American chestnut that once dominated the Southeast.

The towering trees, often called the "kings of the forest," can grow to 100 feet high and 10 feet in diameter. They were nearly wiped out in the 1930s by the chestnut blight fungus, said U.S. Forest Service research forester Stacy Clark.

Nearly wiped out

By the 1950s, practically all American chestnuts were gone.

The blight is an exotic pest that came to the U.S. from Asia, said Clark. It was first discovered at the Bronx Zoo in New York in 1904.

"Before the blight, the chestnut probably made up 25 percent of all trees in the United States," she said. "It was a major environmental catastrophe."

The fungus attacks the bark and leaves the roots alone, allowing the tree to grow back the following year. But as soon as the trees flower, the blight returns, preventing them from growing into the once giant trees.

Researchers at the American Chestnut Foundation are cross breeding the American chestnut with Asian and European varieties resistant to the blight. Some of the hybrids produced are about 94 percent American, said Clark.

The hybrids look much like American chestnuts even though they often have DNA from four different species, she said.

"That's the final product, but there's not any available right now for reforestation," she said. "We're hoping that in five years they'll have some ready for wide distribution."

That's where the forest service comes in, said Clark. She and a team of researchers are planting mixtures of hybrids across the Southeast to determine where they should be planted and what the trees need for survival. Due to a limited supply of the 94 percent hybrids, the foresters are planting chestnuts with varying genetic makeup.

Her team, based at Alabama A&M in Huntsville, planted two groups of hybrids in Bankhead National Forest this month.

Researchers planted hybrids last year in Cherokee National Forest in Tennessee and will plant some in Daniel Boone National Forest in Kentucky next year, she said.

"Where I'm coming from is, if we're going to have these in five years, we need to know where to put them," she said.

Clark said the trees planted in Tennessee showed a 90 percent survival rate. Eight percent have the blight fungus.

Finding a healthy place for even the blight-resistant tree to live is difficult, said Clark. Another danger lurks, threatening to kill the American chestnut — Phytophthora, a pest that lives in the soil and kills the roots and stems.

It's found mostly in the South where temperatures are warm and the soil is moist.

"It's a major problem because if you plant a tree in soil that has Phytophthora, the trees are going to die," she said. "Even if we have a blight-resistant tree, it does us no good if that gets it."

Forest service researchers are finding locations where the trees can thrive. In Bankhead, they planted some in shaded areas where the forest has been thinned and some in open spaces where the forest has been clear-cut.

This will help foresters determine how much sunlight is needed, said Clark.

The researchers are also tracking the trees' genetic makeup so they can let the American Chestnut Foundation know which ones are surviving.

"Of course, the areas where there is Phytophthora are not working, but other than that, they live and grow super fast," said Clark. "They're definitely faster than oaks and probably as fast as yellow poplars, so if we can get them to live, they'll be very competitive."

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