The Enid News and Eagle, Enid, OK

December 8, 2012

Reviving an American icon: Researchers try to bring chestnut back to country

From The Associated Press
Associated Press

ENID, Okla. — WEAVERVILLE, N.C. (AP) — Jim Hurst has doted on his trees, arranged in three “families” on a bluff high above the rushing French Broad River.

He installed a drip irrigation system to help rejuvenate this former hayfield’s powdery, depleted soil. In the four years since planting the fuzzy, deep-brown nuts, he nursed the seedlings — through back-to-back droughts, a killing frost, even an infestation of 17-year locust — applying herbicides and mowing between the rows to knock down anything that might compete.

Then, on a hot day this past June, Hurst moved methodically along the steep hillside, a petri dish in his left hand, and infected the young saplings with the fungus that will almost certainly kill them.

It wasn’t malice, but science — and hope — that led him to take such an action against the trees.

“My mother’s family never stopped grieving for the (American) chestnuts,” the 51-year-old software engineer and father of two said as a stiff breeze rustled through the 110 or so surviving trees, many already bearing angry, orange-black cankers around the inoculation sites.

“Her generation viewed chestnuts as paradise lost.”

Hurst hopes the trees on his farm — part of a vast experiment in forest plots where this “linchpin” species thrived before the onslaught of an imported parasite — might hold the key to regaining that Eden.

The American chestnut once towered over everything else in the forest. It was called the “redwood of the East.” Dominating the landscape from Georgia to Maine, Castanea dentata provided the raw materials that fueled the young nation’s westward expansion.

With trunks measuring 10, 12, even 17 feet in diameter, the trees’ branches soared up to 120 feet above the forest floor.

Along the Appalachian spine, chestnuts covered some 200 million acres — comprising fully a quarter and, in some places as much as two-thirds, of the upland forest. It is difficult to overstate the tree’s importance. Settlers built cabins, rail fences and barns out of its strong, even-grained wood.

Then, the blight struck. By the 1950s, this mightiest of trees was all but extinct — “gone down like a slaughtered army,” in the words of naturalist Donald Culross Peattie.

Now, after 30 years of breeding and crossbreeding, The American Chestnut Foundation believes it has developed a potentially blight-resistant tree, dubbed hopefully, the “Restoration Chestnut 1.0.”

At a national summit in Ashe-ville in October, the group’s board adopted a master plan for planting millions of trees in the 19 states of the chestnut’s original range.

The restoration tree is being introduced onto a physical and economic landscape that has long since learned to do without the once-indispensable American chestnut. Will it crowd out other trees and plants we have come to value in the past century? How do you convince landowners and government agencies it’s worth the money and effort?

“I think that’s something worth fighting for,” Hurst said. “To fix something that’s broken.”

It is unclear when or how the blight arrived here, though most agree it came on chestnuts imported from China or Japan. Carried by insects and on the wind, the blight cut through the forests like an invisible scythe. But the American chestnut has not totally disappeared. Millions of seedlings sprout each year from stumps or buried nuts. Most reach just a few feet in height before the blight — which persists in the soil and on bark of surrounding trees — finds and kills them.

Last year, Traylor Renfro was clearing trails at his mountaintop retreat in Grassy Creek, near the Virginia border, when something pricked his finger. At first, he thought he’d been stung.

“And then when I looked at it, I realized that it was a bur,” he said.

He was aware of the blight, and so his prime suspect was one of the bushlike chinquapins scattered about. His search for more burs led him to a nearby tree, its long, feather-like leaves edged with teeth that resemble breaking ocean waves.

It was an American chestnut — about 37 inches around and at least 50 feet tall. Examining the tree, he could see no signs of blight — giving him hope his tree had developed a defense against the fungus.

“I’m not in denial,” he said, cradling a brown bur in his palm as he stared upward. “But show me one that big.”

Claims of a naturally resistant American, though, are “baloney,” said Paul Sisco, a retired American Chestnut Foundation geneticist.

Soon after the blight was discovered, the U.S. Department of Agriculture began trying to develop a hybrid. Because Chinese and Japanese trees, unlike the American ones, had evolved along with the blight, the emphasis was on crossing native trees with the foreign ones.

“It didn’t matter whether it looked like an American chestnut,” said Kim Steiner, a professor of forest biology at Pennsylvania State University. The goal was simply “some sort of a timber tree.”

After decades and millions of dollars, the government gave up. To be honest, purists weren’t interested in what the government was after, said Steiner.

“We’re not talking about replacing American chestnut,” he said. “We’re talking about restoring American chestnut.”

Enter Charles Burnham.

A corn geneticist by training, Burnham was retired from the University of Minnesota when he read about the government’s failed efforts. He began thinking about ways in which his own successful work with food crops might be applied to the chestnut conundrum.

In 1983, Burnham and several other plant scientists formed The American Chestnut Foundation — built on his program of “backcross breeding.”

Burnham started out with a hybrid between an American and a Chinese chestnut, then backcrossed it with a “pure American.” The progeny of that pairing were then backcrossed to American chestnut a second time; the offspring from that coupling were then crossed a third time back to American stock.

“The approach was a population of near-American chestnuts that would breed true for resistance,” said Steiner.

The product of all that crossing, backcrossing and intercrossing is being put to the test at Hurst’s and hundreds of other breeding orchards around the country. The trees that show the most resistance after inoculation will be used at the seed orchards to produce the next generation.