Ghost forests

In the Clarks Fork area of the Shoshone National Forest, towering evergreen trees stand like skeletons, naked and needleless. The greenery is gone, transformed to what Kurt Allen, an entomologist with the Forest Service, describes as a gray, “ghost forest.” The trees, some dead, and some still struggling to survive without needles, are victims of what Allen calls “the most bizarre” spruce budworm epidemic he’s ever seen. Spruce budworms, despite their name, mainly attack Douglas-fir trees. The insect, which eventually transforms to a gray moth, is native to Wyoming and about every 20 years appears in epidemic proportions.The last big outbreak on the Shoshone was in the mid-1980s. So Allen wasn’t concerned when about four years ago he saw small stands of needleless trees. Spruce budworm winter in the trees and emerge in the spring and feast on tree needles. A tree’s needles catch the sun, which allows it to make the sugars that feed the roots and keep it alive, Allen said. In Wyoming, in particular, May, June and July are prime food-making months. It’s also when spruce budworms are most active. The trees go into survival mode when they lose needles, Allen said. A tree can rebound from one year without needles, even two years. The problem with this epidemic, Allen said, is that has lasted more than three years, much longer than normal. “Trees are living critters, too,” he said. ”They do need food and water at some point.”...more