The hemlock wooly adelgid, an invasive species that attacks hemlock trees, has been spotted in Van Buren County.
Michigan’s invasive species program has been managing the hemlock wooly adelgid since 2017. Trees infested with the aphid-like insect will die in four to ten years without treatment. Two infested trees were spotted in Van Buren State Park in early March.
Heidi Frei of the Michigan Department of Natural Resources said there are about 170 million hemlock trees in the state, and they're an important part of protecting Michigan’s critical dunes.
“When you take away a big component of the forest, what would happen is we would lose a lot of stability on those landscapes,” she said. “So erosion could be possible.”
She says hemlock is sometimes sparse in natural areas, but often grows in dense groves.
“So if we had these huge patches of dead trees, that’s a problematic situation for a state park as far as safety, recreation, landscape, and tourism value,” she said. “And then we start thinking about things like fire, and is that an issue for fire, having a lot of standing dead, dense material. So there’s a lot of things this could impact down the road without management and intervention.”
She said the infestation in Van Buren County was identified in its early stages, so should be controllable.
“At Van Buren State Park, the hemlock population is pretty sparse,” she said. “It’s a beautiful forest, and it’s a high quality forest for us to manage, and so with just a couple of trees there, that’s within reach certainly.”
This makes eleven Michigan counties with confirmed infestations. Frei says adelgid egg sacs look like tiny cotton balls. Any suspected infestations should be reported to the DNR.
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