NEW YORK (AP) — Five prominent species of ash tree in the eastern U.S. have been driven to the brink of extinction from years of lethal attack by a beetle, a scientific group says. Tens of millions of trees in the U.S. and Canada have already succumbed, and the toll may eventually reach more than 8 billion, the International Union for Conservation of Nature said Thursday. Ash trees are a major part of eastern forests and urban streets, providing yellow and purplish leaves to the bounty of fall colors.