Title: Mapping host-species abundance of three major exotic forest pests

Author: Morin, Randall S.; Liebhold, Andrew M.; Luzader, Eugene R.; Lister, Andrew J.; Gottschalk, Kurt W.; Twardus, Daniel B.

Year: 2005

Publication: Res. Pap. NE-726. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station. 11 p.

Abstract: Periodically over the last century, forests of the Eastern United States devastated by invasive pests. We used existing data to predict the geographical extent of future damage from beech bark disease (BBD), hemlock woolly adelgid (HWA), and gypsy moth. The distributions of host species of these alien pests were mapped in 1-km2 cells by interpolating host basal area/ha from 93,611 forest-inventory plots in 37 states. The interpolated surfaces were adjusted for forest density (percent land cover) by multiplying values by an estimate of percent forest cover derived from existing land-cover maps (30-m2 cells). According to our estimates, BBD currently occupies only about 27 percent of its potential range in land area, but has invaded more than 54 percent in total host density. HWA occupies nearly 26 percent of its potential range in land area, and about one-quarter in total host density. Gypsy moth occupies only 23 percent of its potential range in the Eastern United States, and only 26 percent in total host density.