American chestnut trees once made up a quarter of eastern U.S. forests, with four billion of them stretching from Maine to Florida. Virtually all these chestnuts were killed within 50 years by a fungus introduced to the U.S. in 1904. But wildlife biologist Nathan Klaus of the Georgia Department of Natural Resources recently discovered half a dozen American chestnuts near President Franklin D. Roosevelt's Little White House in the southern end of the Appalachians, with the largest some 40 feet tall. “You occasionally find a single American chestnut in the wild, but such a large group of them is unprecedented,” Klaus says. He notes that the chestnut-killing fungus may not have thrived on the dry, rocky mountaintop where this stand dwells. The American Chestnut Foundation announced May 19 it would breed the trees with blight-resistant Chinese chestnuts in the hopes of eventually developing a hardier, mostly American hybrid.