Hybrid chestnut could reforest Appalachia
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Yet people haven't given up on the towering hardwood or slowed efforts to restore it to great swaths of woodland from Maine to Georgia and in the Ohio Valley, where it once reigned through the canopy. Despite the failure of earlier scientific efforts to bring it back, thousands of chestnut aficionados have new reason for optimism
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By interbreeding the American with its Chinese cousin, tree lovers have created an American chestnut with some resistance to Asian blight and have developed a virus that can be injected into affected trees to combat the fungus. It's a project that shows every sign of promise - with about 25,000 of the new chestnuts planted under the guidance of trained scientists and chestnut devotees.
If the hybrid plantings thrive, some envision huge tracts of strip-mined Appalachia one day being restored with lovely chestnut forests.
"We know we're interbreeding resistance. Now we have to figure out, does it have enough resistance?" said Bryan Burhans, president of the American Chestnut Foundation, which has led the revival efforts.
He said it will take 75 to 100 years to know whether the tree can be re-established as a mainstay of Eastern forests. But he said he's "very optimistic" about the American chestnut's future.
Some might be intimidated by the prospect of a century-long recovery effort - more than a person's life span, if not a tree's. But as Robert Mangold, who directs forest protection for the Forest Service, put it, "it's a long-term commitment."
And for those on the front lines of the American chestnut crusade, the commitment has become something of an obsession.
"It's really a compelling story. I just sort of got hooked on it," said Kathleen Marmet, who lives near Warrenton, Va., and became involved seven years ago when she lived in Maryland. "This isn't a problem we can solve in our lifetime, but we can do something that has a chance of possibly making a difference."
A fast-growing, hardy tree that thrives on rocky and acidic soil, the American chestnut served as an economic engine for Appalachia. Families fattened livestock with its nuts and used its wood for fuel, railroad ties, fence posts, musical instruments and furniture. It was a fixture along East Coast and Appalachian streets and highways, where its display of fingery white flowers was a springtime delight.
In its heyday, the towering tree not only formed a critical part of the Eastern hardwood forest - researchers think it made up as much as a quarter of the woods' overstory - but also provided inspiration to poets and novelists.
Henry David Thoreau agonized over pummeling a chestnut with a stone to bring down its nuts: "It is not innocent, it is not just, so to maltreat the tree that feeds us," he wrote in his journal on Oct. 23, 1855.
Almost 80 years later, Robert Frost mused about the chestnut's future in "Evil Tendencies Cancel." ''Will the blight end the chestnut?" he wrote. "The farmers rather guess not / It keeps smoldering at the roots / And sending up new shoots / Till another parasite / Shall come to end the blight."
The chestnut blight, first identified by a Bronx Zoo scientist in 1904, wreaked havoc on the tree; by 1950, researchers estimated that 50 to 100 trees remained.
The phenomenon that Frost observed still exists: In addition to some massive surviving trunks that resisted rot and became known as "old soldiers," small, wild chestnuts continue to pop up, only to fall prey to blight before reaching maturity. Although chestnuts continue to be sold in the United States, those that are offered by street vendors, for example, tend to come from European trees that were not as severely affected by blight.
Doug Boucher, who directs the tropical forest and climate initiative for the Union of Concerned Scientists, based in Cambridge, Mass., came across a young American chestnut in the early 1990s when he was camping in Maryland's Savage River State Forest.
"That looks like it has to be a chestnut, but the chestnut disappeared," he thought to himself. It was only after he saw a second, with its trademark bur, that he realized they survived in the wild. He helped found the Maryland chapter of the American Chestnut Foundation, which is based in Asheville, N.C., and joined the search for ways to reestablish the tree.
The most promising work remains in traditional breeding. After an initial cross with Chinese chestnuts to obtain genetic resistance to blight, volunteers have repeatedly "backcrossed" the offspring with other American chestnuts to produce a tree that is nearly 94 percent American chestnut.
The foundation has roughly 75,000 "mother" and "father" trees in 300 volunteer-run breeding orchards across the United States. Saplings and nuts from these orchards are distributed for plantings. The group is cultivating different trees in separate states and continues to cross-breed, volunteer John Bradfield said, "to bring in the diversity that geography brings to a species."
Researchers, including some at the University of Maryland's Biotechnology Institute, have worked to map the genome of chestnut blight to identify which viruses, when injected into a sick tree, could help counteract the fungus.
They've developed a treatment that is simultaneously high- and low-tech: After scientists identified a few key viral strains, volunteers such as Essie Burnworth cooked up a hypo-virulent soup in her Potomac, Md., home to inject into the cankers of affected American chestnuts.
"I keep it in my refrigerator, and we make new batches every six weeks. We do it in a blender," Burnworth said, adding that in many instances, the injection does the trick. "If you hit the jackpot, then you've saved that tree."
Now that they've got trees with a shot at survival, volunteers have joined federal officials to begin reforestation. They've planted 20,000 to 25,000 chestnuts, and some of the most promising work is being done on land decimated by strip mining that must be restored under federal law.
"Surface mines may make the best springboard for the American chestnut back into the Eastern forest," said Patrick Angel, a senior forester at the Office of Surface Mining who is helping to oversee the effort. "The natural range of the American chestnut and the Appalachian coal fields overlap perfectly."
There are three-quarters to a million acres of abandoned mining land between Pennsylvania and Alabama that could be reforested with chestnuts and other hardwoods, Angel said. "That's a huge amount of non-forested land in an area that used to be contiguous forest," he said.
Some chestnut tree adherents are growing them wherever they can - in their back yards, in neighboring orchards and beyond. Michael Webb has about 40 trees in his back yard and some on a friend's property near Allentown, Pa.
"I've been interested in chestnuts as long as I can remember," said Webb, who recalled looking up the tree in an encyclopedia in elementary school.
Three dozen research scientists at 12 institutions are working on how to re-establish American chestnuts and other native hardwoods under the auspices of the Appalachian Regional Reforestation Initiative. They are seeking to answer basic questions, such as whether it's more effective to plant nuts or seedlings. As Angel said, "The people who really know how to plant chestnuts are dead. They died off with the species when the blight came through."
The chestnuts that have been planted with other species are thriving, with survival rates of 80 to 90 percent. "We're seeing phenomenal growth," Angel said.
With time, those who love the American chestnut may realize the vision of Barbara Kingsolver's fictional farmer Garnett Walker in the novel "Prodigal Summer."
"He worked like a driven man, haunted by his arboreal ghosts, and had been at it for nearly a decade now," Kingsolver writes. "If he lived long enough he would produce a tree with all the genetic properties of the original American chestnut, except one: it would retain from its Chinese parentage the ability to stand tall before the blight. It would be called the Walker American chestnut. He would propagate this seedling and sell it by mail order that it might go forth and multiply in the mountains and forests of Virginia, West Virginia, Kentucky, and all points north to the Adirondacks and west to the Mississippi. The landscape of his father's manhood would be restored."
.
By interbreeding the American with its Chinese cousin, tree lovers have created an American chestnut with some resistance to Asian blight and have developed a virus that can be injected into affected trees to combat the fungus. It's a project that shows every sign of promise - with about 25,000 of the new chestnuts planted under the guidance of trained scientists and chestnut devotees.
If the hybrid plantings thrive, some envision huge tracts of strip-mined Appalachia one day being restored with lovely chestnut forests.
"We know we're interbreeding resistance. Now we have to figure out, does it have enough resistance?" said Bryan Burhans, president of the American Chestnut Foundation, which has led the revival efforts.
He said it will take 75 to 100 years to know whether the tree can be re-established as a mainstay of Eastern forests. But he said he's "very optimistic" about the American chestnut's future.
Some might be intimidated by the prospect of a century-long recovery effort - more than a person's life span, if not a tree's. But as Robert Mangold, who directs forest protection for the Forest Service, put it, "it's a long-term commitment."
And for those on the front lines of the American chestnut crusade, the commitment has become something of an obsession.
"It's really a compelling story. I just sort of got hooked on it," said Kathleen Marmet, who lives near Warrenton, Va., and became involved seven years ago when she lived in Maryland. "This isn't a problem we can solve in our lifetime, but we can do something that has a chance of possibly making a difference."
A fast-growing, hardy tree that thrives on rocky and acidic soil, the American chestnut served as an economic engine for Appalachia. Families fattened livestock with its nuts and used its wood for fuel, railroad ties, fence posts, musical instruments and furniture. It was a fixture along East Coast and Appalachian streets and highways, where its display of fingery white flowers was a springtime delight.
In its heyday, the towering tree not only formed a critical part of the Eastern hardwood forest - researchers think it made up as much as a quarter of the woods' overstory - but also provided inspiration to poets and novelists.
Henry David Thoreau agonized over pummeling a chestnut with a stone to bring down its nuts: "It is not innocent, it is not just, so to maltreat the tree that feeds us," he wrote in his journal on Oct. 23, 1855.
Almost 80 years later, Robert Frost mused about the chestnut's future in "Evil Tendencies Cancel." ''Will the blight end the chestnut?" he wrote. "The farmers rather guess not / It keeps smoldering at the roots / And sending up new shoots / Till another parasite / Shall come to end the blight."
The chestnut blight, first identified by a Bronx Zoo scientist in 1904, wreaked havoc on the tree; by 1950, researchers estimated that 50 to 100 trees remained.
The phenomenon that Frost observed still exists: In addition to some massive surviving trunks that resisted rot and became known as "old soldiers," small, wild chestnuts continue to pop up, only to fall prey to blight before reaching maturity. Although chestnuts continue to be sold in the United States, those that are offered by street vendors, for example, tend to come from European trees that were not as severely affected by blight.
Doug Boucher, who directs the tropical forest and climate initiative for the Union of Concerned Scientists, based in Cambridge, Mass., came across a young American chestnut in the early 1990s when he was camping in Maryland's Savage River State Forest.
"That looks like it has to be a chestnut, but the chestnut disappeared," he thought to himself. It was only after he saw a second, with its trademark bur, that he realized they survived in the wild. He helped found the Maryland chapter of the American Chestnut Foundation, which is based in Asheville, N.C., and joined the search for ways to reestablish the tree.
The most promising work remains in traditional breeding. After an initial cross with Chinese chestnuts to obtain genetic resistance to blight, volunteers have repeatedly "backcrossed" the offspring with other American chestnuts to produce a tree that is nearly 94 percent American chestnut.
The foundation has roughly 75,000 "mother" and "father" trees in 300 volunteer-run breeding orchards across the United States. Saplings and nuts from these orchards are distributed for plantings. The group is cultivating different trees in separate states and continues to cross-breed, volunteer John Bradfield said, "to bring in the diversity that geography brings to a species."
Researchers, including some at the University of Maryland's Biotechnology Institute, have worked to map the genome of chestnut blight to identify which viruses, when injected into a sick tree, could help counteract the fungus.
They've developed a treatment that is simultaneously high- and low-tech: After scientists identified a few key viral strains, volunteers such as Essie Burnworth cooked up a hypo-virulent soup in her Potomac, Md., home to inject into the cankers of affected American chestnuts.
"I keep it in my refrigerator, and we make new batches every six weeks. We do it in a blender," Burnworth said, adding that in many instances, the injection does the trick. "If you hit the jackpot, then you've saved that tree."
Now that they've got trees with a shot at survival, volunteers have joined federal officials to begin reforestation. They've planted 20,000 to 25,000 chestnuts, and some of the most promising work is being done on land decimated by strip mining that must be restored under federal law.
"Surface mines may make the best springboard for the American chestnut back into the Eastern forest," said Patrick Angel, a senior forester at the Office of Surface Mining who is helping to oversee the effort. "The natural range of the American chestnut and the Appalachian coal fields overlap perfectly."
There are three-quarters to a million acres of abandoned mining land between Pennsylvania and Alabama that could be reforested with chestnuts and other hardwoods, Angel said. "That's a huge amount of non-forested land in an area that used to be contiguous forest," he said.
Some chestnut tree adherents are growing them wherever they can - in their back yards, in neighboring orchards and beyond. Michael Webb has about 40 trees in his back yard and some on a friend's property near Allentown, Pa.
"I've been interested in chestnuts as long as I can remember," said Webb, who recalled looking up the tree in an encyclopedia in elementary school.
Three dozen research scientists at 12 institutions are working on how to re-establish American chestnuts and other native hardwoods under the auspices of the Appalachian Regional Reforestation Initiative. They are seeking to answer basic questions, such as whether it's more effective to plant nuts or seedlings. As Angel said, "The people who really know how to plant chestnuts are dead. They died off with the species when the blight came through."
The chestnuts that have been planted with other species are thriving, with survival rates of 80 to 90 percent. "We're seeing phenomenal growth," Angel said.
With time, those who love the American chestnut may realize the vision of Barbara Kingsolver's fictional farmer Garnett Walker in the novel "Prodigal Summer."
"He worked like a driven man, haunted by his arboreal ghosts, and had been at it for nearly a decade now," Kingsolver writes. "If he lived long enough he would produce a tree with all the genetic properties of the original American chestnut, except one: it would retain from its Chinese parentage the ability to stand tall before the blight. It would be called the Walker American chestnut. He would propagate this seedling and sell it by mail order that it might go forth and multiply in the mountains and forests of Virginia, West Virginia, Kentucky, and all points north to the Adirondacks and west to the Mississippi. The landscape of his father's manhood would be restored."
Read more: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/10/24/MN5L1FU998.DTL&ao=all#ixzz14AJxSTSa
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