Gypsy Moth on a New Frontier: Forest Tree Defoliation and Mortality

Abstract

Abstract The gypsy moth infestation in central Pennsylvania has been closely monitored between 1979 and 1984 for tree defoliation and subsequent mortality. These losses serve as an indicator of potential impact as gypsy moth invades new territory. Tree mortality on study plots averaged 18%, worth $18.80 per acre. During the three most severe defoliation years (1980-82), plots that averaged less than 10% defoliation lost 13% of their trees by 1984. Where defoliation averaged 40% or more, the average tree loss was 28%. Timber losses predicted with models developed from the 1970s infestation in northeastern Pennsylvania were within 2% of the actual average loss. The models seem to be acceptable for obtaining broad regional estimates of potential tree mortality and value loss. North. J. Appl. For. 4:128-133, Sept. 1987.