SP678 Forest management Strategies to Minimize the Impact of the Gypsy Moth

Use of silviculture to manage gypsy moth effects gives foresters additional tools for developing integrated pest management programs. Silvicultural actions should be taken prior to gypsy moth outbreaks to reduce or minimize the potential damage that arises in stands vulnerable to gypsy moth. Three approaches to reduce stand susceptibility to gypsy moth are applicable. First, change the stand composition by reducing the proportion of favored species and increasing the number of non-favored species in the stand. This can be accomplished through intermediate thinning treatments. The percentage of favored species that remain should be less than 30 percent of total composition.

Second, improve the growing conditions for residual trees. The more vigorous the tree, usually indicated by crown condition (size and density), the more likely it is to survive defoliation whether a favored or non-favored species. Intermediate thinnings create more space for crown expansion of residual trees. The released trees will grow larger with more vigorous crowns.

Third, between gypsy moth outbreaks, in situations where defoliation and mortality have already occurred, salvage dead trees and thin live trees as needed. The increased growing space for the remaining trees should create a healthier stand that can better withstand the next outbreak of gypsy moth.