Estimating the Age of Demarcation of Juvenile and Mature Wood in Douglas-Fir

Abstract

In order to characterize trends and to estimate the age of transition from juvenile to mature wood in Douglas-fir, piecewise linear regression analysis was applied to the radial pattern of intra-ring characteristics found in increment cores of Douglas-fir trees sampled at breast height.The data were collected with X-ray densitometry.Average ring density of all trees along the radius showed an initial decline within the first ten rings from the pith, a rapid increase to about ring thirty, and a continued increase at a lower rate thereafter.Three main wood-density profiles were found amone trees.Piecewise ~ ~ regression models were used successfully to characterize radial development of wood density and to determine the demarcation of juvenile and mature wood.