AUGUSTA, Maine – An invasive insect that kills hemlock trees has been discovered at a Maine state park in South Berwick, the third state park at which the insect has been found, according to Maine Department of Conservation officials. It is thought to be the most western location of the insect found to date in Maine.
A “light touch” of hemlock woolly adelgid (HWA) was found Friday at Vaughan Woods State Park during an insect survey being conducted by a group of 15 volunteers, Park Manager Glenn Dochtermann said Friday afternoon. The insect was discovered in two or three trees, he said.
“We’ve been lucky so far, but our luck ran out,” Dochtermann said.
The infestation eventually will change the character of the forest at the state park, but it also will give significant information on how HWA develops and affects the trees, Allison Kanoti, Maine Forest Service entomologist, said Friday.
The infestation “will give us some important data regarding how quickly impacts from hemlock woolly adelgid are expressed following the buildup of the insect to detectable levels,” Kanoti said. “That information really is missing for Maine and will be valuable.”
Hemlock woolly adelgid is a small aphid-like insect that is covered with white, waxy wool-like material. This wool-like covering makes the insect resemble miniature cotton balls. It is most visible from late-October through July. Wool masses are located on the undersides of the twigs at the bases of the needles.
The insect, which came from Japan in the 1950s, causes infested trees to have off-color needles, often with a grayish cast, and premature needle drop and twig dieback.
Hemlock trees are a significant Maine tree species and are one of the major trees found at Vaughan Woods, Kanoti said. Usually found near water bodies, hemlocks contribute to the state’s forest ecosystem. They protect the forest floor from erosion and help water quality particularly by buffering water temperatures, which can affect such species as brook trout. Hemlocks also are important in deer wintering areas.
HWA has been found in at least 16 states and was first discovered in Kittery in 2003. Since then, it has been spreading up the coastal area of Maine. The insect was found at Ferry Beach State Park in 2008 and at Wolfe’s Neck Woods State Park in Freeport this past summer, Kanoti said.
Vaughan Woods is 250-acre forested tract along the Salmon Falls River known for its old-growth stands of pine and hemlock. The Maine Bureau of Parks and Lands (BPL) and MFS scheduled Friday’s survey at the park with a group of volunteer surveyors.
Dochtermann said that the HWA was found on Warren Way, a quarter-mile spur off the park’s main trail. The park manager praised the volunteers, saying “they did a wonderful job” of examining the park’s trees.
Kanoti said that “a pretty good component of the tree cover at Vaughan Woods is hemlock, so as the hemlock woolly adelgid develops, the trees will decline and die off slowly.”
The MFS entomologist predicted that the park trails would start to appear more open and more hardwood species would develop to replace the hemlock. She also said that the park might experience more erosion, as hemlock tree roots are important in holding onto soil.
Dochtermann said the volunteer group will continue to do surveys at the park to monitor the infestation. The group also is expected to survey Fort McClary State Historic Site at Kittery Point.
More information about the hemlock woolly adelgid can be found at: http://www.maine.gov/doc/mfs/InvasiveThreats.htm
For information about Maine state parks and historic sites, go to: http://www.parksandlands.gov