Yellowstone's Green Promise

In the summer of 1988, wildfires consumed nearly 800,000 acres of Yellowstone National Park. Visitors wept at the blackened ridgelines, the skeletal lodgepole pines, the ash-gray meadows where elk had grazed just weeks before. Rangers fielded angry letters from Americans who believed the park was ruined forever. But the lodgepole pine holds a quiet secret. Its cones are serotinous — sealed shut with resin that only melts in extreme heat.…