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Pennsylvania DCNR Bureau of Forestry and U.S. Forest Service (USFS) of Eastern Region, worked together with the National Park Service to release predatory beetles as a biological control agent for the hemlock woolly adelgid. The predatory beetles, (Laricobius nigrinus), feed exclusively on adelgids that infest the hemlock trees. The eastern hemlock trees are a symbolic design feature at the memorial, and were witness to the events that happened here on September 11, 2001.
Last updated: February 23, 2022