By Dan Shapley
Over 50 years, Dutch Elm Disease spread across the nation, killing the elms that once lined streets in most American cities. Now, American elms - cultivated from the few individuals resistant to the fungus - are being sold for the first time in large numbers. The long effort to restore the tree received its biggest boost this year, when Home Depot decided it would sell 12,000 American elms. It's not a big number, compared to the number of species it sells. But it marks a significant stride in the comeback of a quintessential American tree.