Mortality equations for individual trees in the mixed-conifer zone of southwest Oregon

Abstract

Models of stand growth and yield must include an estimate of mortality. For individual-tree/distance-independent growth-and-yield models. it is necessary (1) to predict the probability of death of individual trees and (2) to keep stand projections within reasonable biological limits (e.g., the maximum basal area that the stand can achieve). In this study, the probability of death of an individual tree is predicted by a logistic equation with coefficients estimated for tree species growing in the mixed-conifer zone of southwest Oregon. Overall stand projections are controlled by use of sizedensity trajectories that govern the approach of the stand to the maximum size-density line.