The Northeastern United States is home to the Appalachian Hemlock Forests of which many are currently threatened by the woolly adelgid, an invasive insect that destroys eastern hemlock trees.
As average global temperatures continue to climb, infestations of the hemlock woolly adelgid are creeping up the East Coast of North America. Hemlock stands throughout the Eastern U.S. are becoming increasingly vulnerable to this non-native species introduced from Japan.
The Appalachian Hemlock Forest ecological system is one of the main forest types of Northeastern America ranging from central New England west to Lake Erie and south to the higher elevations of Virginia and West Virginia.
Currently a wide range of factors threaten the 155 national hemlock forests with at least a dozen forests being critically endangered. These forests are seriously at risk due to endemic infestations of the woolly adelgid as well as the human activities of mining, logging, air and groundwater pollution, and deforestation from clear cutting all of which result in significant ecosystem fragmentation.
The destruction and loss of Appalachian Hemlock Forests is also globally significant because hemlocks are integral to the ecosystems they inhabit and extensive temperate deciduous forests are very rare worldwide.
Northern hardwoods such as sugar maple, yellow birch, and beech are characteristic in this ecosystem either forming a deciduous canopy or mixed coniferous canopy with hemlock. Other common and sometimes dominant trees include red oak, tulip tree, black cherry and black birch.
The Appalachian Hemlock Forest ecosystem and range are more limited in the southern part of its U.S. geographic location.