By Gwendolyn Craig
Two invasive species known for killing ash and hemlock trees have spread beyond where they were originally discovered in the southern Adirondack Park. Hemlock woolly adelgid and emerald ash borer were found in a handful of new locations during last year’s surveys conducted by the Adirondack Park Invasive Plant Program and its partners.
Officials are still hopeful that mitigation techniques could stem the worst of hemlock woolly adelgid, but the fate of the park’s ash trees is grim.
“We take each finding and feel sad about it,” said Tammara Van Ryn, manager of APIPP, a branch of the Nature Conservancy.
Emerald ash borer
Emerald ash borer is an Asian beetle first discovered in the Adirondack Park in 2020 at the Warren County boat launch in Chester along the Schroon River. Detections of EAB were confirmed all around the park so its arrival to the park seemed inevitable. Van Ryn and her colleagues believe the bugs were burrowing and proliferating in the region for several years.
Surveys in 2020 and 2021 radiated from the boat launch and four of five ash borer traps showed no sign of the invasive species. But last year EAB was caught in a trap in Bolton Landing at the Lake George Land Conservancy’s Amy’s Park. A private landowner in Johnsburg also discovered sick ash trees on their property. Van Ryn said they were infested with EAB too.
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Ash borers are not good at flying, traveling a mile or two in a year, Van Ryn said. They’re usually transported with the help of humans through firewood. That’s how Van Ryn and others think the Warren County boat launch infestation started. The Amy’s Park infestation was close enough to the Warren County boat launch, Van Ryn said, that the beetles could have traveled there themselves. But the Johnsburg EAB likely had some human assistance.
In APPIP’s 2021 annual report, EAB is listed as a tier 4 invasive species. It’s the dreaded category to indicate that an invasive species is too widespread or too difficult to eradicate.
But Van Ryn offered some hope.
About 7% of the park’s forest is ash trees. Since EAB is slow-moving, its spread is partially in the hands of the public. The best thing people can do is to not transport firewood, Van Ryn said. The state Department of Environmental Conservation’s firewood regulations allow for untreated firewood to be transported up to 50 miles.
The Nature Conservancy has also identified stands of ash trees throughout the park that it will monitor for EAB. There’s a possibility, Van Ryn said, that some trees could survive an EAB attack. This could help scientists and foresters cultivate ash trees that could live alongside EAB.
Also coming to the fight for ash trees is the U.S. Department of Agriculture. Its Animal and Plant Health Inspection Service has experimented with biocontrols, in this case different kinds of wasps, that eat EAB. A spokesperson for the service said it began releasing these wasps in New York state in 2011. The service has not confirmed if the wasps are keeping EAB from spreading, the spokesperson said.
However, a Michigan study showed the wasps kill 20% to 80% of EAB in ash trees up to 8-inches in diameter.
“The study documented that more EAB are being attacked by the wasps which is resulting in less EAB attacking ash trees, and that ash trees are regenerating in these areas because wasps are being released,” the spokesperson said.
Hemlock woolly adelgid
Flies and beetles that eat these pepper flake-sized bugs were released along the eastern shores of Lake George last year. The DEC also injected and sprayed pesticides on trees along the coastline. A DEC spokesperson said the department will apply for another Adirondack Park Agency permit to use the pesticide this year.
Mark Whitmore, director of the New York State Hemlock Initiative out of Cornell University, said more biocontrols could be released this year depending on if there’s enough adelgid for them to eat. Whitmore said this winter’s cold snaps could have helped reduce the HWA population.
“We don’t have the data yet from our Lake George study site, but elsewhere in the Finger Lakes and around Ithaca, we have in some places 99% mortality, which is really news for the trees,” Whitmore said. “That, in combination with the treatments that we’ve done, hopefully will really slow the march, slow the spread in the area.”
Surveys completed last year show HWA has spread along the eastern shore north to Black Mountain point, Van Ryn said. It was originally found in 2020 by a camper in Washington County. DEC and APIPP surveys later showed HWA on 250 acres including along Shelving Rock Bay and Paradise Bay. Van Ryn said it’s hard to tell if the Black Mountain area infestation is new or just newly identified.
HWA has also spread across the lake to private property near Diamond Point.
HWA is so small that even a gust of wind moves the invasive species. Van Ryn said HWA in Lake George will never be completely eradicated, but the state and partners can keep the population low.
Hemlocks act as temperature controls, shading the shoreline and keeping waters cool for certain fish species. They help keep shorelines from eroding and runoff from degrading water quality. They are also the most common shoreline tree on Lake George, Whitmore said. Losing them would change the landscape dramatically.
The public can also help look for HWA. Winter is the perfect time, Van Ryn said, to see HWA’s iconic white woolly masses underneath hemlock branches.
“My message is always that we have the ability, we as recreationists, boaters, sportsmen and women, there’s so much we can do to prevent the spread of invasive species,” Van Ryn said.
Though it’s concerning for the Adirondack Park forestland to find new EAB and HWA infestations, Van Ryn is encouraged that private landowners are speaking up when they see changes in their backyards.
“It really takes everybody to learn about it and to care about it,” she said.
APIPP and partners will host a virtual workshop on how to identify HWA from 10 to 11:30 a.m. on Wednesday, Feb. 16.
Participant surveys for HWA will take place on the following:
- Lake George Region – Feb. 17, Hosted by the Lake George Land Conservancy
- Coles Woods, Queensbury – Feb. 24, Hosted by the Capital Region PRISM
- Moreau Lake State Park, Corinth – Feb. 24, Hosted by the Capital Region PRISM
- Ausable River Watershed – March 2, Hosted by the Ausable River Association
- Keene Valley – March 19, Hosted by the Adirondack Mountain Club
More information can be found at https://adkinvasives.com/Events/.