Long-Term Effects of Defoliation of Aspen by the Forest Tent Caterpillar

A second study of the effect of aspen of defoliation by the forest tent caterpillar in Minnesota was conducted 6 years after the conclusion of an initial comprehensive investigation. Results indicate increasing mortality in other than suppressed trees with increasing defoliation intensity. Hypoxylon, Nectria, and insect incidence increased with defoliation intensity. Growth is significantly reduced 1 year beyond the cessation of defoliation in stands where three successive heavy defoliations have occurred. Growth of the dominants increases significantly, however, the third year after defoliation in such stands.