There’s a war going on in the Great Smoky Mountains.
On one side is an army of invaders who are disturbing the native flora and leaving an array of dead trees in their wake.
These menacing killers in the Smoky Mountains are the hemlock wooly adelgids, an insect native to East Asia.
On the other side of this war is the National Park Service (NPS), who have banded together with an army of predatory beetles.
What’s eating the trees in the Smoky Mountains?
The reason you see so many dead trees in the Great Smoky Mountains National Park is largely due to this balsam wooly adelgid insect.
The insects leave tall, dead trees standing out in stark contrast to the forests’ thick green canopy.
This species was a noted killer of Fraser firs on Mount Mitchell in North Carolina as far back as 1957.
Over the subsequent decades, the fir population was severely harmed.
By the 80s, the situation was deemed apocalyptic.
There were fears the Fraser firs would suffer the same fate as the American chestnut, which nearly succumbed to a fungus accidentally introduced to the region in the 40s.
However, with park officials taking steps to counter the adelgid and the forest itself developing genetic resistance, the Fraser fir is making a comeback.
A similar result is hoped for with the hemlocks.
Called the “redwood of the east,” eastern hemlocks can grow more than 150 feet tall on trunks measuring six feet in diameter.
Some hemlocks in the park are over 500 years old, according to the NPS.
“Over 800 acres of old-growth hemlock trees grow in the Smokies, more than in any other national park. Younger hemlock forests of 75-100 years in age cover an additional 90,000 acres of land in the park.”
Originally discovered in 2002, adelgid infestations have now spread throughout the park’s hemlock forests.
In many areas, infested trees have now died.
How do the adelgids attack?
Adelgid infestations are easy to spot by the appearance of tiny “cotton balls” at the base of hemlock needles.
This appearance is most visible from fall through spring, according to the NPS.
“The hemlock woolly adelgid feeds on the sap at the base of hemlock needles, disrupting nutrient flow and causing the needles to change from deep green to a grayish green, and then fall off,” says the NPS.
“Without needles to capture sunlight (the process of photosynthesis) the tree starves to death, usually within three to five years of the initial attack.”
Infestations usually start with mature hemlocks, but the insects also attack and kill younger trees.
Is this happening in other places?
The hemlock wooly adelgid exists in Eastern Asia and the Western United States.
However, the combination of natural predators and host resistance limits the damage done by the bug in both places.
Hey, what about that legion of predatory beetles?
I would very much like to make some Beatles puns here, but the facts of the case are far too interesting to be mucking about.
In 2002, park officials took a cue from the old lady who swallowed a fly and upped the ante. They unleashed an army of predatory beetles on the forest. These little beetles feed exclusively on adelgids.
Ha, take that you sap suckers.
By 2011, the park had unleashed over half a million beetles. Preliminary indications are that the results are encouraging.
In fact, you might say “I’ve Got a Feeling” that everything is going to “Come Together” and the situation is “Getting Better”.
What else is being done?
Other steps of action include various treatments.
Hemlocks in accessible areas are treated with insecticidal soaps and horticultural oils. These treatments are distributed by truck-mounted spray units with an 80-foot reach.
Off trail hemlocks that can’t be reached by the insecticidal super soaker have their soil treated. Alternatively, they can have insecticide injected directly into the trunk.
How can I help?
Efforts to control hemlock woolly adelgids are being funded through the Save the Hemlocks initiative of the Friends of Great Smoky Mountains National Park, a nonprofit organization.
For additional information, or to learn more about how you can help, visit the Friends of the Great Smoky Mountains National Park‘s website or call (865) 932-4794.
Did you know that’s why there were so many dead trees in the Smokies? Let us know in the comments.