The Great Smoky Mountains National Park has been given the green light to wage a full-scale assault on the hemlock woolly adelgid.
The regional director of the National Park Service has approved the park's preferred alternative for fighting the insect using a combination of chemical and biological controls.
About 20 comments were submitted during the public review process, most of them in support of the park's proposal.
The finding of no significant impact means park managers can expand on the treatment program that has been in effect since the insects were discovered in the Smokies in 2002.
That program includes treating individual trees with insecticides injected either in the soil or directly into the tree; spraying trees with an insecticidal soap; or releasing "predator" beetles that feed on the hemlock woolly adelgid.
The predator beetle is the park's primary weapon against the hemlock woolly adelgid in the backcountry. Two species of predator beetles are being raised at a special lab at the University of Tennessee. Early this year, the park released 1,700 predator beetles at the Chimneys area.
Chemical controls are more feasible in treating trees that are accessible by roads. The environmental study states that the treatment methods have been thoroughly analyzed and offer the best protection for water resources and nontarget species.
Kristine Johnson, supervisory forester for the Smokies, said the park is authorized by the National Environmental Protection Act to expand its chemical-control option farther into the backcountry.
"We thought it would be better to do an environmental assessment to cover the whole program since it looks like we are going to be in this for the long haul," Johnson said.
The national forests that surround the Smokies - Cherokee National Forest in Tennessee and the Pisgah and Nantahala national forests in North Carolina - already have completed similar environmental assessments for treating the adelgids.
The hemlock woolly adelgid kills hemlock trees by sucking juice out of the needles. The insect was accidentally imported into North America from Asia in the early 1930s. The hemlock woolly adelgid is a relative of the balsam woolly adelgid, which killed more than 90 percent of the park's Fraser firs between the 1960s and 1990.
As of December 2005, park crews had treated at least 28,000 hemlock trees, covering approximately 450 acres with insecticides. More than 360 acres of hemlocks in the Smokies have been treated with insecticidal soap sprays.
The Smokies contains about 18,000 acres of hemlock-dominated forests. The trees typically grow along streams and play a pivotal role in maintaining cool water temperatures for trout and other species during the summer.
While large-scale die-offs of hemlocks have not yet occurred in the Smokies, some trees are showing signs of visible foliage damage, and scattered areas of mortality are expected soon.
Park Superintendent Dale Ditmanson said the goal is to suppress the adelgid population level to the point that some hemlock stands survive and reproduce in the future.
"Our best hope for success is to reduce the hemlock mortality in order to sustain stands of healthy, viable trees - particularly in old growth forests and in high visitor-use areas," Ditmanson said.Knox News
