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Welcome to the Eastern Forest Environmental Threat Assessment Center!
Eastern forests are vulnerable to stresses from insects and disease, wildland loss, invasive species, uncharacteristic fire, and climate change. As new threats emerge and old threats resurface, the Eastern Forest Environmental Threat Assessment Center (EFETAC) is an interdisciplinary resource that is actively developing new technology and tools to anticipate and respond to emerging eastern forest threats. Center researchers work with other scientists nationally as well as with a variety of Federal, State, and local government agencies, universities, and non-governmental partners to address these threats. More...
Message from the Director...
Dr. Danny C. Lee
Welcome to the Eastern Forest Environmental Threat Assessment Center’s Web site – a resource for cutting edge research, technology, and tools addressing emerging forest threats. Our site is intended to be a user-friendly, reliable, and timely source of information for anyone interested in environmental threats.
EFETAC is addressing a variety of complex issues that demand cross-disciplinary integration, collaboration, and creativity. Our work complements ongoing efforts within and outside the Forest Service and builds on a wealth of existing information. Our scientists collaborate with an extensive national and international research community and focus on research that is relevant to rural and urban forest threat issues. More...
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Featured Forest Threat
Hemlock Woolly Adelgid (Adelges tsugae)
Hemlock woolly adelgid, native to Asia, was first reported in 1951 near Richmond, Virginia. By 2005, it was established in portions of 16 states from Maine to Georgia, where infestations covered about half of the range of hemlock.
What is hemlock woolly adelgid? Hemlock woolly adelgid (HWA) is a tiny, aphidlike insect that varies from dark reddish-brown to purplish-black in color. As it matures, it produces a covering of wool-like wax filaments to protect itself and its eggs, which can be readily observed from late fall to early summer on the underside of the outermost branch tips of hemlocks. Ovisacs of the winter generation contain up to 300 eggs; spring ovisacs contain between 20 and 75 eggs. When hatched, first instar nymphs (called crawlers) search for feeding sites on twigs at the base of hemlock needles, and once settled, feed on young twig tissue and remain at that location throughout their development.
How does it spread? Dispersal and movement of HWA occur primarily during the crawler stage as a result of wind and by birds, deer, and other forest-dwelling animals that come in contact with the sticky ovisacs and crawlers. Isolated infestations and long-distance movement of HWA, though, most often occur due to the transport of infested nursery stock.
Why is hemlock woolly adelgid a concern? HWA threatens the health and sustainability of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana) in the eastern U.S. Unlike closely related insects that feed on nutrients in sap, HWA feeds on stored starches critical to the tree’s growth and long-term survival. Hemlock decline and mortality typically occur within 4 to 10 years of infestation in HWA’s northern range, but can occur in as little as 3 to 6 years in its southern range. Other hemlock stressors, including drought, poor site conditions, disease, and other insect pests accelerate the rate and extent of mortality.
