Western Journal of Applied Forestry (July 2003), pp. 207-212.
Douglas-fir (Pseudotsuga menziesii var. menzeisii) is an important and abundant tree species in coastal British Columbia. Juvenile height estimates are important for management prescriptions and decisions involving regenerating stands. We used 100 plots to investigate the juvenile height growth of coastal Douglas-fir. The growth patterns of the sample trees were observed by felling and splitting them longitudinally and measuring the height of the annual nodes from the point of germination. Sixty-four plots were used to develop a height model as a function of total age and site index. The Chapman-Richards, Gompertz, and modified exponential and power models were fit using nonlinear least squares regression. The models were tested with the remaining 36 plots. The modified exponential and power equation was the best fitting of the three models. None of the models met the regression assumption of independently normally distributed residuals with a mean of zero and a constant variance. The modified exponential and power model was further analyzed using the complete data set by fitting height growth and incorporating a model for serial correlation in the error term to improve the statistical properties of the model. West. J. Appl. For. 18(3):207–212.
