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RALEIGH, N.C. (Nov. 5, 2004) — A century after blight all but wiped out the chestnut, scientists are fighting to save another majestic tree, according to Wildlife in North Carolina magazine. Hemlocks in
the Great Smoky Mountains National Park are under siege from a tiny
insect, the
state’s wildlife magazine reports in its November
issue. The woolly adelgid — named for a white tuft it produces — attaches
itself to the base of a hemlock needle, where it sucks the tree’s
vascular fluids. Infested by thousands of woolly adelgids, the hemlock
eventually loses its needles and dies. A die-off would affect entire ecosystems because hemlocks are the second-most common tree in the Great Smokies. Taking their place would be oaks and other hardwoods, or possibly even exotic invasive plants. Several species of migratory birds nest almost exclusively in hemlocks. Grouse, wild turkey and deer rely on hemlock canopies for cover. Aquatic wildlife would also take a hit. Recent research has shown that streams shaded by hemlocks tend to be cooler than those shaded by hardwoods. Because trout prefer cooler water, they can be two or even three times more populous in hemlock-shaded streams. Aquatic invertebrates are also much more prevalent in hemlock-shaded streams. And the temperature difference makes hardwood-shaded streams more likely to dry up. Foresters and biologists are seeking ways to save Appalachian hemlock forests. Chemical solutions work on individual trees, but not on a forestwide scale. One controversial approach has been to introduce natural predators from the woolly adelgid’s native Asia, which concerns scientists who fear the potential consequences of introducing one exotic species to combat another. One particularly promising candidate is a tiny relative of the ladybug that seems to feed exclusively on the woolly adelgid and, once its preferred prey is gone, promptly dies off itself. Not just specialists can help control the woolly adelgid. Landscapers and homeowners who purchase a hemlock for planting should ask the nursery to make certain the plants are pest-free. And outdoors enthusiasts who encounter the telltale white tufts on the underside of hemlock needles should wash their clothes to prevent spreading the insect to another area. Wildlife in North
Carolina magazine is a monthly educational publication of the
N.C. Wildlife Resources Commission. For subscription
information,
call toll-free (866) 945-3746 or fill
out a subscription form. |
