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King of Trees. Redwood of the East. Such were names for the American chestnut, which dominated forests throughout the eastern United States only a century ago. With a signature, colossal canopy towering up to 150 feet, the chestnut comprised one in four trees in many areas and showered the earth with chestnuts, food for a teeming array of white-tailed deer, wild turkey and Passenger Pigeons.
Because of its characteristic arrow-straight trunk and massive canopy, foresters called it the “perfect tree.” Besides supporting wildlife and pleasing the senses, the chestnut was economically important for its rot-resistant wood, tasty nuts and tannic acid, used to stain furniture.
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| Purdue researcher Douglass Jacobs stands in front of a 90-year-old chestnut near West Salem, Wisc. A rarity, the tree has survived this long because it was outside the chestnut’s (and, therefore, the blight’s) native range. |
Vanishing breed
But the American chestnut—like the sun-eclipsing pigeon flocks that the tree helped feed—was not as stable as its prominent role must have suggested. In 1904, an accidentally introduced fungus blight was discovered in the Bronx Zoo, brought there on chestnuts shipped from East Asia. Cryphonectria parasitica, as the canker-causing fungus is called, began to rapidly spread, killing every tree it infected. In fewer than 40 years, the fungus had made its way throughout the chestnut’s territory, leaving nothing behind but a swathe of “ghosts,” as locals called the dead trees, from Maine to Mississippi.
The American chestnut did not go extinct, however (unlike the Passenger Pigeon, which was obliterated by 1914). The species can still occasionally be seen in its original territory when shoots arise from old roots, although these rarely reach reproductive age before becoming reinfected and dying back again. Some counts put the number of home-range American chestnut trees at fewer than 100 (measured as individuals larger than 2 feet in diameter), whereas estimates put the original population at several billion trees.
Together we stand
But researchers from Purdue University and the American Chestnut Foundation (ACF) hope to change that, working to breed a blight-resistant American chestnut to be reintroduced into the wild.
“We are just beginning to see the fruits of our work after more than 20 years,” says Douglass Jacobs, an associate professor of forestry and natural resources, who has been involved in the work for the past five years. “The chestnut disappeared overnight, and its disappearance left an impact that we cannot even begin to fully appreciate. Proper reintroduction of the chestnut could produce enormous benefits.”
Since the early 1980s, the ACF has focused its work on cross-breeding the American chestnut with the Asian chestnut, a related tree that has natural resistance to the fungus. The breeding process aims to produce trees that retain all the American chestnut genes and have the resistance-causing genes from the Asian species.
Jacobs and his ACF colleagues have been successful in producing trees that are resistant and exhibit all the structural features of the American chestnut; one ACF tree was planted on the White House lawn in 2005. However, because of time and funding constraints, it could be more than 10 years before seeds will be available to the general public.
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