Saving the Hemlocks from Invasive Species

March 6, 2014

Insects smaller than your pointer finger are taking down the giant hemlocks, the “redwoods of the east” that can grow as high as 150 feet, says Randy Edwards in a Nature Conservancy blog. Only the most recent of a long line of devastating invasive species, the hemlock woolly adelgids are killing hemlocks from Georgia to Maine, with no end in sight.

Hemlocks are vital components of their forest ecosystems, providing “dense, cooling shade and organic, acidic soils that create a set of plant and animal species different from the typical hardwood forests of the southern and central Appalachians.” Love trout fishing? Thank the hemlock forests that cool the ambient temperature of the water and allow the fish to thrive.

Though the hemlocks will be replaced by beeches, maples, or other trees, gaps caused by dying hemlocks may create opportunities for additional invasive species. In the long term, other species do not provide the cooling mechanisms than hemlocks have become known for, changing the species composition of the forests.

There’s no doubt that the woolly adelgids are devastating; in the Great Smoky Mountains National Park they have decimated 90% of the native hemlocks. However, there is hope, both in science and in the conscientiousness of citizens. First, researchers are conducting studies to test whether “a tiny Asian beetle that is a natural predator to the adelgid” can keep its population in check. If that remains unfeasible, “scientists are working on an adelgid-resistant strain of hemlock.”

Second, while research is moving forward people can focus on their own actions to halt the spread of this and other invasive species. Do not transport firewood, but buy and burn locally. Don’t feed birds in areas where hemlocks are healthy, as migratory birds may spread the adelgids. Keep an eye out for the insects, and if you see “small, fluffy white balls at the base of the needles,” call your local officials and alert them immediately.

Invasive species are a national and international problem that require billions of dollars and hundreds of thousands of volunteer hours to combat. If you’re interested in helping fight invasive species here in the Triangle, sign up for one of TLC’s volunteer days to remove invasive species from our beautiful nature preserves. Check out our Facebook or Events page for volunteer opportunities!

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