Growth and mortality of ponderosa pine poles thinned to various densities in the Blue Mountains of Oregon.

Abstract

Growth and mortality in a ponderosa pine (Pinus ponderosa Dougl. ex Laws.) stand were investigated for 24 years. High mortality rates from mountain pine beetle (Dendroctonus ponderosae Hopkins) occurred on some plots where values for stand density index exceeded 140. Periodic annual increments for quadratic mean diameters decreased curvilinearly as stand density increased, whereas periodic annual increments of gross basal area and gross cubic volume increased curvilinearly with increasing stand density. Cubic volume yield at a stand age of 84 years increased linearly with increasing density. Mean annual increments of board foot volume increased with time and show no signs of leveling off at a stand age of 84 years. Mean annual basal area and volume growth of the 30 largest trees per acre decreased with increasing levels of stand density. Ponderosa pine on low sites should be managed at low stand densities to avoid problems with mountain pine beetle and to produce large trees in a reasonable time period. Long rotations are probably possible for this species.

Citation

Cochran, P.H.; Barrett, James W. 1995. Growth and mortality of ponderosa pine poles thinned to various densities in the Blue Mountains of Oregon. Res. Pap. PNW-RP-483. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 27 p