Maximum size-density relationships for mixed softwoods in the northeastern USA

Abstract

The maximum size-density relationships or self-thinning lines were developed for three mix .ed-softwood climax forest habitats (hemlock-red spruce, spruce-fir, and cedar-black spruce) in the northeastern USA. The plot data were collected from an extensive data base used in growth studies from 1950 to 1970, and represented a wide range of species compositions, sites, management options, and densities. Plots having late successional species compositions with relative density index higher than 0.7 were selected as the most fully-stocked plots for model development. Reduced major axis regression was used to fit the self-thinning lines to the data. The differences between the three forest habitats were tested using the 95% confidence intervals of the coefficients of the self-thinning lines. The results indicated that there were no differences between the hemlock-red spruce and spruce-fir habitats for both relationships of the mean tree volume versus number of trees, and the quadratic mean I tree diameter versus number of trees. Thus, these two habitats were combined to develop a single self-thinning line. However, the cedar-black spruce forest habitat required a separate self-thinning line. These maximum size-density relationships can be readily used to construct stand density management diagrams.

Citation

Solomon, Dale S.; Zhang, Lianjun. 2002. Maximum size-density relationships for mixed softwoods in the northeastern USA. Forest and Ecology Management 155:163-170