This month hundreds of volunteers along the Appalachian Trail will trade excited e-mails detailing when they plan to pollinate their chestnut trees with special pollen—one more step in a twenty-year effort to restore the American chestnut to its majestic place in the northeastern and mid-Atlantic forest. Until a century ago billions of American chestnuts came into flower before the start of July, making the hillsides they favor look buried in snow. As tall as the tallest oak, with a diameter of up to ten feet in a clear field, the chestnut made up fully a quarter of the forests in its native range, from southern Canada to Georgia.
In America as in Europe, the chestnut was the "bread tree," providing a staple that could be boiled and mashed to replace potato as a starch, ground into flour to make noodles or bread (a favorite use of the Cherokee, who made chestnut cornbread), or eaten out of hand, either raw or roasted, for a nutritious, filling snack. In October the vast stands provided an almost limitless supply of free food, dropping nuts that glistened like gemstones and fed not only people but also wild turkeys, pigs (whose ham made Virginia famous), and other animals that were themselves important foods. Chestnuts, easy to dry, gave Appalachian families a source of income and a way to survive the winter.
Creamy, slightly crunchy, delicately sweet without seeming starchy or bland, fresh American chestnuts taste almost like fresh water chestnuts, to which they aren't related. This was one of several revelations I had recently when I tasted "Americanoid" chestnuts, as the enthusiastic grower calls his hybrid American-Asian nuts—an advance sample of what all those volunteers are working toward (and available to anyone by phone or Internet order). Often no bigger than large marbles, American chestnuts have a relatively high ratio of surface area to volume, which enables them to convert starch to sugar faster than do the European and Asian chestnuts we are used to—chestnuts that have been bred to be big. American chestnuts are intensely flavored nuggets by comparison.
Other revelations: American chestnuts have far softer shells (which are easy to cut or bite through) and are miraculously free of the bitter skin that stubbornly clings to more familiar chestnuts. Cut in half and cooked for a few minutes in a microwave oven, they practically leap out of their shells. Thus it is now easy to pair chestnuts, fresh or dried, with the many things they nicely complement, including roasted root vegetables, seafood soups, and—now in season where chestnut trees once reigned—asparagus.
This is an auspicious moment to become familiar with the virtues of the American chestnut. The goal of reviving the tree is coming into view faster than anyone expected twenty years ago, when a few researchers adopted a new approach to reversing one of the great environmental tragedies in American history. In 1904 a fungus was discovered on a chestnut at the New York Zoological Park: Asian chestnuts, which brought the blight, were resistant, American not. The blight caused by the fungus moved through forests at up to fifty miles a year. Lumber companies, shortsightedly assuming that death was inevitable, began clear-cutting chestnut forests, selling the valuable timber—light, rot-resistant, easy to work, handsome in paneling and furniture—for railroad ties and telephone poles. Many of the fences built along the Appalachian Trail under the Work Projects Administration were of chestnut; they guide hikers to this day. Any natural resistance the forests may have harbored was lost in the clear-cutting. By 1950 nine million acres that had been covered with American chestnuts were covered with gray stumps. Wildlife populations plummeted, and along with them the food they had provided. (Horse chestnuts, being another species entirely, were immune from the blight. Their shiny nuts encased in spiky burrs resemble true chestnuts, but the nuts, called "buckeyes" in America and "conkers" in England, contain bitter tannins and sufficient acetone to make them potentially toxic.) A free subsistence crop disappeared from Appalachia, where poverty had long been another blight.
The revival of the American chestnut could catalyze the first large-scale success in restoration ecology, which aims to bring entire ecosystems to working health. This branch of ecology, still young, differs from movements such as permaculture, which encourages people to devise strategies to make healthy ecosystems flourish and endure. (Like sustainable agriculture, with which it overlaps, permaculture looks for ways to let people live off the land without fundamentally altering it.) Restoration ecologists have looked to ruined ecosystems such as strip-mined land and watersheds wrecked by logging—challenges requiring help from governments and landowners, who usually don't want to give it. Restoring the chestnut forest is a more straightforward goal.
The chestnut was the challenge facing early-twentieth-century American botanists. For decades, however, chestnut blight, which kills by girdling the tree with cankers that work inward and choke off its food supply, resisted all attempts to keep it in check or circumvent it. Because the fungus that causes it lives in the bark of other trees, such as oak and ash, without killing them, the blight still thrives in the chestnut's original range, killing off chestnut seedlings as they reach maturity. (Blight doesn't affect the root system; seedlings grow on stumps, sometimes for several years, before blight fells them.) Researchers crossed the blight-resistant Asian chestnut trees with American chestnuts and then, in classic fashion, crossed resulting generations, too, with Asian chestnuts, in order to introduce as many Asian genes as possible; no one knew which genes or how many conferred resistance. The work was terribly slow: it takes three to five years to prove that a cross is blight resistant. The crosses seemed certain to look like Asian trees, which are far shorter than the American species and shaped differently. And every cross failed. The intensive efforts that had begun in the 1920s petered out in the 1960s.
In the late 1970s Charles Burnham, a well-known plant geneticist, offered fresh hope. He hypothesized that blight resistance could be conferred by crossing American-Asian hybrids in the opposite direction—to American rather than Asian chestnuts, continually diluting out most Asian genes except those few that carried blight resistance. Burnham began working to create a blight-resistant tree that would preserve many more American characteristics, collaborating with Philip Rutter, a biologist and ecologist who was already trying similar breeding experiments.
The goal suddenly seemed decades, not centuries, away. The federal government had ended the chestnut program it had sponsored since the 1930s, so a group of independent researchers who had been seized by the chestnut dream formed the American Chestnut Foundation in 1983, with the grandiose aim of repopulating the Appalachians with American chestnuts. The smaller nuts of a true American chestnut, or something as close to it as possible, might not bring as high a price as the Asian chestnuts under commercial cultivation in California—but the benefits to wildlife populations would be incalculable. The oaks that took the place of chestnuts in many areas produce acorns irregularly, whereas chestnuts drop huge crops of easy-to-eat nuts year after year. The forests would benefit too. Rutter, who served as the foundation's president for ten years, estimates that a forest dominated by chestnut trees grows 30 percent faster than one dominated by oaks; the hyperactive chestnut produces sugar from sunlight all winter, staying bright green beneath its thin bark year-round. Also, the chestnut is a gorgeous tree.