 The first backcrossed American chestnut tree, called "Clapper", survived blight for 25 years, and grafts of the tree have been used by The American Chestnut Foundation since 1983.The Pennsylvania chapter of The American Chestnut Foundation, which seeks to restore the American chestnut to the forests of the Mid-Atlantic states, has planted over 22,000 trees.The Surface Mining Control and Reclamation Act of 1977 requires owners of abandoned coal mines to cover at least 80 percent of their land with vegetation.