Last year was a busy year for the Great Smoky Mountains National Park's hemlock woolly adelgid control effort since the park began battling the insect in 2002.
As of December 2005, park crews had treated at least 28,000 hemlock trees covering approximately 450 acres with systemic insecticides. An additional 360 acres of hemlocks in the park have been treated with insecticidal soap sprays.
The park has been able to ramp up its fight against the invasive insect thanks to financial support from the U.S. Forest Service and the Friends of the Smokies. The money has paid for a full-time coordinator and six forestry technicians, as well as two trucks and a farm utility vehicle equipped with sprayers.
Winter is a busy time of year for hemlock woolly adelgid control because the insects are most active during cold weather. The Smokies' control strategy includes treating individual trees with insecticidal sprays and soil treatments, and releasing non-native "predator" beetles, which feed on hemlock woolly adelgids, in the backcountry.
The hemlock woolly adelgid already has destroyed virtually the entire hemlock forest in Virginia's Shenandoah National Park. The tiny, non-native insect was discovered in the Smokies in 2002 and has since been identified in all of the park's major watersheds.
Kristine Johnson, forestry supervisor for the Smokies, said there is good news in the fact the park is battling the infestation in its early stages.
"We are working much more aggressively than anyone else has," Johnson said. "We have the greatest hemlock resource, so we have more to lose."
The Smokies contains about 18,000 acres of hemlock-dominated forests. The trees grow mostly along stream drainages and play an important role in cooling water temperatures for fish and other aquatic life during the summer.
The Smokies places a high priority on treating hemlock trees along primary roads and campgrounds to ensure visitor safety, preserve the views, and avoid the maintenance cost of having to remove trees after they die.
The park estimates that its treatment of hemlock trees at Elkmont has saved more than $61,000 in hazardous tree removal costs.
Hemlock trees around the park's backcountry campsites also have been treated to control the hemlock woolly adelgid.
Park visitors already can see the difference between hemlock stands that have been chemically treated and ones that haven't because of their inaccessibility. An example would be the healthy hemlocks in the Chimneys picnic area versus hemlocks higher up on the ridge that have suffered visible needle loss because of the infestation.
"Certainly in the short term, people in a few years will begin to notice the difference between the areas we treat and maintain and the areas we can't treat," Johnson said.
While forestry crews treat front country hemlocks with chemicals, their primary hope in the park's backcountry is biological control - namely, the predator beetle.
Park crews recently released about 1,700 predator beetles at the Chimneys area - the first predator beetle release of the year. The beetles were raised at the University of Tennessee.
While large-scale die-offs of hemlocks have not yet been observed in the backcountry of the Smokies, park officials say they expect to see scattered areas of mortality throughout the park in the near future.
"The most optimistic long-term scenario is that the hemlock woolly adelgid population will decline as biological controls take over," Johnson said. "We don't expect to ever eradicate the hemlock woolly adelgid from the park. Our goal is to achieve a level of suppression that enables some trees to survive and reproduce in the future."Knox News
