On May 18, 1980, people all over the world watched with awe and horror as Mount St. Helens erupted. Fifty-seven people were killed and hundreds of square miles of what had been lush forests and wild rivers were to all appearances destroyed. Ecologists thought they would have to wait years, or even decades, for life to return to the mountain, but when forest scientist Jerry Franklin helicoptered into the blast area a couple of weeks after the eruption, he found small plants bursting through the ash and animals skittering over the ground. Stunned, he realized he and his colleagues had been...