The giant American chestnut tree all but disappeared 70 years ago, killed by a blight that struck at the turn of the last century. By 1950, an estimated four billion of these magnificent trees were gone from our Eastern forests, and the tree, once dominant, is considered functionally extinct. We talk with researchers and volunteers who are working with promising new technologies to restore the American chestnut tree. There are still wild remnants of the tree in our forests - could you identify