Growth of Regeneration Defoliated by Spruce Budworm in Idaho

摘要

Mathematical equations are presented for predicting growth and development of regeneration as a function of species, tree condition, site characteristics, and western spruce budworm defoliation. The dataset consists of 1,183 host trees on which growth and defoliation were followed concurrently for 5 years. Probability of dieback is positively related to budworm defoliation and positively related to crown ratio. Crown ratio decreases with increasing defoliation, but the effect is delayed. Indications are that the probability of mortality is positively related to defoliation and negatively related to crown ratio.