Pest threatens regions’ hemlocks

By DAVID HULSE

MONGAUP, NY — They’ve already wiped out a large portion of the hemlock trees in the Delaware Water Gap and now the National Park Service (NPS) is warning that a potentially devastating tree pest has been confirmed in the Upper Delaware.

The hemlock wooly adelgid, Adelges tsugae, was identified this spring on hemlock trees in the state’s bald eagle wintering area in the Mongaup area, NPS Resource Specialist Michael Reuber reported last week. The NPS has an interest in the area, the future site of the park’s primary visitor center.

Adelgids are aphid-like insects that infest Eastern and Carolina hemlocks, sucking nutrients from them to the point of starving the trees. Infestation can be spotted by the small, cottony egg masses the adelgids leave at the base of needles.

New York Department of Environmental Conservation (DEC) Regional Natural Resources Supervisor Bill Rudge said there is very little that the state can presently do about the problem on a large scale. Rudge said individual trees can be treated for adelgids, but widespread spraying in the hemlock’s rugged habitat is impossible.

There is also a biological deterrent, a beetle imported from Japan, but at $2 a beetle, “they’re very expensive little beetles,” he said.

For private property owners with hemlock stands, Rudge suggested that the best preventative measure was to stop feeding wild birds, as he said they are the primary carriers for the adelgids.

Working with the U.S. Forest Service, Reuber said the NPS acquired 2,800 of the predator beetles, which DEC recently released in selected areas along the Mongaup River.

Reuber said that getting the public aware of the danger is “one of those things,” where people don’t necessarily understand the implications. He noted that hemlocks are the predominant species in many of the region’s rocky ravines, where few other plants will grow. Losing the hemlocks will lead to warmer water temperatures in areas where fish need cold water.

Other experts refer to the “micro-climate” provided by hemlocks, which cool deeply forested areas in summer and provide cover and warmth for many species of forest animals in winter.

Reuber said the NPS is planning an informational forum to alert property owners and the general public.