Tiny Pest Threatens Appalachian Giants

By on October 14, 2013

Hemlock Woolly Adelgid

The peaceful quiet of winter can be deceptive. While the mountains are hushed with occasional snowfall and bears are drowsy in their dens, a stealth army of tiny predators is silently waging war with deadly results. The hemlocks – the graceful green giants that for centuries have characterized the Appalachians, contributed to their health and beauty, and created a special sense of place long treasured – are being attacked and killed by an invasive insect accidentally imported from Asia in the 1950s, the hemlock woolly adelgid (HWA).

HWA are smaller than a grain of pepper, barely visible to the naked eye, but in spring (and again in fall to a lesser extent) their presence can be detected by their white woolly egg sacs about the size of a peppercorn on the underside of the hemlock branches. They’re also phenomenally prolific, capable of multiplying from one egg sac to as many as 90,000 offspring in a single year. Equipped with a straw-like mouth part called a stylet, millions of them can literally suck the life out of a mature hemlock in as few as three to six years here in the South.

The infestation in Georgia was first detected in Rabun County in 2002 and has spread steadily westward as far as Cloudland Canyon. Unable to fly, HWA are consummate hitchhikers, traveling on the wind, the feathers of birds, the fur of animals, and even on us and our clothes. Great swaths of dead and dying trees can now be seen in the northeast part of the state, and tree decline is becoming quite noticeable in the north central counties.

Why does this matter? Aesthetically, these most beautiful of trees contribute greatly to the enjoyment of all who live, work, and play among them generation after generation. Environmentally, hemlocks provide food and habitat for about 120 species of vertebrates and more than 90 species of birds, shade for native plants, cool temperatures for trout streams, and protection for air and water quality. Economically, healthy evergreens such as hemlocks are important both to individuals in terms of property values and to communities in terms of tourism and recreation which support thousands of related jobs and bring over a million dollars of revenue to the state annually.

The consequences of losing our hemlocks would be devastating, long-lasting, and possibly irreversible. The good news is that there are ways to avoid this catastrophe, but the time frame for taking effective action is perilously short.

Property owners have options once the infestation is nearby or their trees are actually infested: (1) do nothing and their hemlocks will die, or (2) treat and save as many hemlocks as they choose. The most reliable treatment is application of a systemic product by pouring or injecting it into the soil at the base of the tree or (in the case of one product) spraying it onto the bark of the trunk. Most property owners find the treatment process easy enough to do themselves and relatively inexpensive, especially compared with the cost of losing their trees, but there are also several qualified professionals who specialize in saving hemlocks and offer their services for reasonable rates. Spring is the best time to treat hemlocks, so property owners should inspect their trees now and take immediate action if the infestation is present. Once treated, the trees are protected for several years, depending on the product used.

On our public lands, government organizations such as the U. S. Forest Service, the Georgia Forestry Commission, and the Georgia Department of Natural Resources are using a program of chemical and biological controls to combat the HWA and reduce its impact. In designated hemlock conservation areas, the protocol includes treatment of selected hemlocks with insecticides, release of several species of predator beetles that are the natural enemy of the HWA, and in some cases a combination. Given the thousands of acres and millions of hemlocks on public lands, the goal is not to save all the hemlocks, but to preserve significant hemlock stands, maintain genetic material for diversity and reforestation, and establish a long-term viable solution that will allow hemlocks to survive and even thrive in the future.

Help is available to property owners wanting to save their hemlocks. Save Georgia’s Hemlocks (SGH), a nonprofit organization which recently received the 2012 Cox Conserves Heroes award, can provide information on identifying and evaluating a HWA infestation, choosing an appropriate treatment product, where to buy it, how to estimate the cost, where to borrow application equipment for free, how and when to do the treatment, and how to manage a large or neighborhood-wide project. For individuals who don’t prefer the do-it-yourself approach, SGH can provide a list of professionals who are properly qualified, licensed, insured, and experienced in treating hemlocks.

Hemlocks volunteersThere are also opportunities to help save hemlocks on our public lands. Through special agreements that Save Georgia’s Hemlocks has in place with the U. S. Forest Service and the Georgia Department of Natural Resources, individuals can volunteer to participate in sponsored projects to treat trees in the national forest, state parks, and wildlife management areas; volunteers are much needed and warmly welcomed. Another way to help is through tax-deductible contributions directly to any of the university-based research labs that raise predatory beetles for release on public lands; contact names and mailing addresses are available on the SGH web site.

The stakes are high, the time is short, and there is much to do. Save Georgia’s Hemlocks urges readers to help by taking care of their own trees, sharing the hemlock message with their neighbors, volunteering for projects on public lands, supporting the beetle labs, and joining SGH in its battle to save the hemlocks.

Donna Shearer is the Chairman of  Save Georgia’s Hemlocks and was instrumental in winning the 2012 Cox Conserves Heroes award for SGH.

Save Georgia’s Hemlocks is a 100% volunteer, 501(c)(3) nonprofit organization of concerned citizens dedicated to preserving, conserving, and restoring endangered hemlocks through education and charitable service. To learn more, please call the Hemlock Help LineSM at 706. 429. 8010 or visit www.savegeorgiashemlocks.org.