Top-height growth components and site index curves, based on permanent sample plot data for New Zealand Pinus radiata D. Don, were used in growth models stratified into eight growth modelling regions. The application of an age adjustment based on seasonal growth patterns helped to reduce variation caused by different measurement dates and the rapid and sustained growth of P. radiata throughout the year. Global and local parameters in a stochastic differential equation version of the Bertalanffy-Richards model were estimated simultaneously by maximum-likelihood. Various parameterisations were tried. The procedure has worked reliably, giving satisfactory predictions and making full use of the available data. Comparison of the models obtained showed significant differences across regions, justifying the initial regionalisation and indicating that a broader aggregation would not be advisable.
Keywords: growth models; height growth; site index; height/age curves; Pinus radiata.
New Zealand Journal of Forestry Science 29(1): 131-145 (1999)