EASTERN HEMLOCK (tsuga canadensis)
This dense, evergreen conifer tree is found in climax communities– forests that have been unaffected by human or natural disturbance, allowing different species of tree of various ages to form a complex and diverse ecosystem. It is one of the few trees that can gradually grow up to the canopy without receiving much sunlight, and it can live for hundreds of years. This eastern hemlock is one of the oldest trees in the Chesterwood forest, with an estimated age of 232 years.
Ecological Relationships: The eastern hemlock provides a habitat for black bears, martens, fishers, bobcats, white-tailed deer, snowshoe hares, red squirrels, porcupines, ruffed grouse, pileated woodpeckers, yellow-bellied sapsuckers, goldfinches, crossbills, and grosbeaks.
The eastern hemlock also has strong associations with many mushrooms, and participates in the mycorrhizal fungi network– the underground system of fungi, joined with plant roots, that allow plants to communicate and share resources. For instance, even if the trunk of an eastern hemlock tree is cut down, the stump and roots will continue to thrive underground, supplied with energy and nutrients from other healthy trees, and exchanging resources in return.
Ecological Threats: Hemlock wooly adelgid.
In 2009, the U.S. Forest Service found that the hemlock wooly adelgid is altering the carbon cycle of eastern forests; they predict that the pest could kill most of the region’s trees within the next decade. In response, entomologists from the Forest Service, Cornell University, and UMass-Amherst have released laricobious nigrinus beetles, a natural predator of hemlock wooly adelgid, to hopefully reduce the population and save the eastern hemlock.