Skip to main content
U.S. flag

An official website of the United States government

Maintenance of eastern hemlock forests: Factors associated with hemlock vulnerability to hemlock woolly adelgid

Author(s):

Petra Bohall Wood

Year:

2010

Publication type:

Other

Primary Station(s):

Northern Research Station

Source:

In: Rentch, James S.; Schuler, Thomas M., eds. 2010. Proceedings from the conference on the ecology and management of high-elevation forests in the central and southern Appalachian Mountains; 2009 May 14-15; Slatyfork, WV. Gen. Tech. Rep. NRS-P-64. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 31-38.

Description

Eastern hemlock (Tsuga canadensis [L.]) is the most shade-tolerant and long-lived tree species in eastern North America. The hemlock woolly adelgid (Adelges tsugae) (HWA), is a nonnative invasive insect that feeds on eastern hemlock and Carolina hemlock (Tsuga caroliniana Engelm.). HWA currently is established in 17 eastern states and is causing tree decline and wide-ranging tree mortality. Our data from West Virginia and Pennsylvania suggest that hemlock crown vigor (a ranking of amount of live crown) relates to a predictable pattern of hemlock vulnerability at light and moderate levels of HWA infestation. We found that crown variables, such as live crown ratio and crown density and transparency, are accurate predictors of hemlock decline; more vigorous trees appear to be less vulnerable to HWA. Thus, silvicultural thinning treatments may be a means for reducing stand densities and increasing crown vigor in colder areas where climate may slow HWA spread.

Citation

Fajvan, Mary Ann; Bohall Wood, Petra. 2010. Maintenance of eastern hemlock forests: Factors associated with hemlock vulnerability to hemlock woolly adelgid. In: Rentch, James S.; Schuler, Thomas M., eds. 2010. Proceedings from the conference on the ecology and management of high-elevation forests in the central and southern Appalachian Mountains; 2009 May 14-15; Slatyfork, WV. Gen. Tech. Rep. NRS-P-64. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 31-38.

Publication Notes

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
https://www.fs.usda.gov/treesearch/pubs/36052