Millions of lofty, straight American chestnut trees once forested the eastern United States with their dense canopy of saw-toothed leaves, making an umbrella for a host of native wildlife. During the late 1800s, a determined squirrel could have traveled from Atlanta, Georgia to Bar Harbor, Maine aboard the outstretched boughs of chestnut trees without ever touching the ground. Yet, according to Philip Rutter, president emeritus of the American Chestnut Foundation, it would have been a lean and mean rodent by journey’s end, for the chestnut’s spiny bur has been described as “the most effective anti-squirrel device nature has invented.” Humans weren’t deterred, though, and many trees became fine Early American furniture. The wood, resistant to rot and weather, split with a straight grain and carved easily. Its bark—rich in tannic acid—was used to tan leather.