Percent decay estimation using decayed wood area at breast or stump height

Abstract

The estimation of tree percent decay is important for estimating the quantity and quality of wood available for timber products. Several different independent variables have been used to estimate the percent decay of standing trees, but often the resulting percent decay predictions are poor. Other independent variables are required for more precise prediction of percent decay. The objective of this study was to examine the use of percent decay area measured at breast or stump height as a possible variable for estimating tree percent decay. Data used in testing included one species group, true fir (Abies spp.), and two species, western red cedar (Thujaplicata Donn) and trembling aspen (Populustremuloides Michx.), from several zones of the province of British Columbia. The use of percent decay area at either breast or stump height resulted in substantial improvements in the estimation of percent decay for all species in all zones. As an alternative to the expensive task of measuring percent decay area on all trees, a sampling design is suggested and one possible design is illustrated.