Acadia wildlife biologist Bik Wheeler prunes a young hemlock tree beside the Jordan Stream Trail. PHOTO COURTESY OF ANP

Hemlock insects are now in Acadia  

ACADIA NAT’L PARK — Hemlock woolly adelgid (HWA), the aphid-like insect that attacks and can ultimately kill hemlock trees, was recently discovered inside the park. 

The Islander reported last week that the insects had been found coating the branches of some hemlock trees on Land and Garden Preserve property at the Cobblestone Bridge, which is just a few steps south of the boundary with Acadia. 

Soon after that discovery, HWA was found on the Acadia side of the property line, according to Jesse Wheeler, the park’s biologist/vegetation program manager. 

“We detected it on branches of young hemlock trees and older hemlock trees, short ones and tall ones, at the edge of both the carriage road and the Jordan Stream Trail. 

“Likely, the infestation of adelgid has been there for a couple of years or more. But it hasn’t come to the level where we’re seeing a decline in the health or vigor of the trees. Right now, they look fairly healthy; they have dark green needles. Most of the needles are remaining on the trees that have adelgid on them.” 

Wheeler also found one small, infected branch on a tree at the Amphitheater Bridge over Little Harbor Brook. 

If people or horses brush against an infected branch, they can transfer the adelgid to a healthy hemlock tree. So, Acadia staff have pruned hemlock branches along the trails and carriage road where the adelgid has been found to try to prevent further migration of the insect.  

Maine Forest Service entomologist Colleen Teerling and members of her team will be in Acadia Aug. 11 to survey the hemlocks in the Jordan Stream corridor. 

 “They will help us try to ascertain what the infestation level really is there, and they can provide recommendations on possible next steps,” Wheeler said. 

He said the U.S. Forest Service has a Forest Health Protection program that can provide similar service and possibly money for pest suppression measures. 

“The Park Service doesn’t have a lot of funding sources for this that we could immediately go to,” Wheeler said. 

He has known that it was just a matter of time before HWA would make its way into Acadia. 

“We have seen it in some forest settings and some backyard settings for a bit now on Desert Island and particularly in the town of Mount Desert,” he said. “But this is by far the most I’ve seen in a forested setting, so it’s still kind of shocking.” 

Wheeler said he doesn’t expect HWA to lead to a lot of tree deaths anytime soon, but he urged property owners to be on the lookout for signs of the insect on their hemlocks. He said they can contact the Maine Forest Service for information and advice. 


Dick Broom

Dick Broom

Reporter at Mount Desert Islander
Dick Broom covers the towns of Mount Desert and Southwest Harbor, Mount Desert Island High School and the school system board and superintendent's office. He enjoys hiking with his golden retriever and finding new places for her to swim. [email protected]
Dick Broom

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