Overhead, two dozen open burrs still hung from the chestnut’s limbs. The burrs, like the tree’s curled and deeply toothed leaves, had spent the winter on the tree. The nuts they once held had tumbled to the ground the previous fall. By now, the sweet chestnut flesh was probably walking around the woods of Cornish, New Hampshire, in the guise of a white-tailed deer, turkey, black bear, or gray squirrel.
Of course, the joy of seeing this mature chestnut tree, Castanea dentata, was tempered by the sight of an orange pox that covered the tree’s glossy bark and filled its lower furrows. Three feet off the ground, the tree was rent by a gaping wound. On the opposite side, a smaller, sunken wound promised to kill off the bole in the near future. The pox and wounds were the result of the chestnut blight, Cryphonectria parasitica, which has re-written the story of the Appalachian forests, including those here in New Hampshire and Vermont.
Fifty million years ago, before plate tectonics moved the continents as far apart as they are now, the northern latitudes of Europe, Asia, and North America all shared numerous plant and animal species. Japanese and Norway maples are close relatives of our own maples; birds like the willow tit and black-capped chickadee, and plants like wild ginger, ginseng, and a host of others, still have close relatives across the oceans. The chestnut genus, too, has a foot on each continent. Ten to thirteen million years ago, the American chestnut diverged from its closest relative, the Chinese chestnut.
During the Ice Age, North American chestnuts, oaks, and hickories found refuge south of the ice near the Gulf of Mexico. As the glaciers melted, oaks and beeches spread back north to New England (some 9,000 years ago). They came by air-mail: blue jays gather small nuts, like acorns, and hoard them in caches up to a half-mile from the source tree. Chestnuts, however, are too large for jays. The chestnuts moved north via squirrels, arriving in New England only 2,000 years ago.
Where established on well drained, slightly acidic sites, American chestnuts were fast-growing, rot-resistant canopy trees that provided a steady fall mast crop. They dominated many forests that now sport white and red oak.
In the 1877 Atlas of the State of New Hampshire, William Flint showed the distribution of chestnuts reaching up the Merrimack to the north end of Lake Winnipesaukee and closely following the 400-foot contour along the Connecticut River north through Cornish and Windsor. On the Vermont side, Chestnuts were found as far north as Colchester in the Champlain Valley. According to ecologist Charles Cogbill, chestnuts in Connecticut composed up to 10 percent of some forests. In New Hampshire and Vermont, chestnut comprised five percent or less of the forest’s mix of trees.
In 1905, American chestnuts growing at the Bronx Zoo were stricken by blight, the first incidence in North America. The spores released by the pycnidia (the fruiting bodies of the fungus that are visible on the tree as the orange pox) traveled 20 to 50 miles each year thereafter. By 1950, all of the American chestnuts in the East had been afflicted by the disease. Most died, while some, usually growing in topographical isolation survived. A few continue to hold on as shrubs, repeatedly sprouting from the healthy root stock as the primary stem dies again and again. Local foresters and naturalists have discovered humbled and resisting chestnuts in Canaan and West Rumney, New Hampshire, and Fairlee, Berlin, and Colchester, Vermont. I recently saw 25 trees still surviving in Newport, New Hampshire.
The American chestnut has no effective defenses against the fungus. Japanese chestnuts (Castanea crenata) and Chinese chestnuts (C. mollissima), however, show a high natural resistance to the blight, having co-evolved with it in Asia.
So fans of chestnuts remain hopeful. The American Chestnut Society in Bennington, Vermont, is promoting new plantings. A long-term breeding project has crossed American, Japanese, and Chinese chestnuts to acquire genes for blight resistance and has back-crossed the result to create a tree that has 93 percent of the genes of the American species with a high level of resistance to blight. While the Chinese chestnut is an orchard tree, this new chestnut hybrid grows tall like the forest tree of eastern North America. While it doesn’t grow as fast as white pine, it grows faster than red oak.
Our forests are always changing. The elms are largely gone, and the beeches are disappearing from the canopy. Perhaps, with a little luck and a lot of hard work, the chestnut may again prove to be a useful timber and wildlife tree in the forests of New Hampshire and Vermont.
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