The damage is obvious along the boardwalk at Congaree Swamp National Monument, said naturalist Fran Rametta. The caterpillars have stripped many of the smaller sweet gums and some oaks. The largest trees have been spared so far. The caterpillars can quickly transform a tree full of spring green into a winter-like hunk of naked limbs. Fortunately, the damage seldom is deadly.
Trees adapt by digging into their energy storerooms to produce more leaves.
That results in less tree growth for the season, and it can make the trees more susceptible to disease, said Forestry Commission spokesman Ken Cabe. Forestry officials began to notice the outbreak last week. The caterpillars usually feed for only a couple of weeks. They aren't expected to spread out of the swamps this year. During the last major outbreak in the mid-1980s, the caterpillars reached populated areas.