Allometric relations of deciduous (Larixoccidentalis) and evergreen conifers (Pinuscontorta and Pseudotsugamenziesii) of the Cascade Mountains in central Washington

Abstract

Logarithmic equations for estimating component biomass and projected leaf area from stem diameter and (or) sapwood cross-sectional area were computed for western larch (Larix occidentalis Nutt.), lodgepole pine (Pinus contorta Dougl.), and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in a mixed conifer stand in the Cascades of central Washington. Regression equations for estimating foliage biomass reported in this study did not compare favorably with foliage biomass allometric relations from other studies. For a given diameter, western larch supported a greater current foliage mass than lodgepole pine or Douglas-fir (P < 0.001); however, the total foliage mass of lodgepole pine was significantly greater (P < 0.001) than western larch. Despite lodgepole pine supporting a total foliage mass approximately twofold greater than western larch, allometric relations between foliage area and stem diameter were not different (P < 0.05) between the deciduous and evergreen conifer. Western larch supports a needle morphology that provides a greater photosynthetic surface area per unit of carbon invested than evergreen conifers in this environment.