Simple linear model reliably predicts bark thickness of radiata pine in the Australian capital territory

Abstract

A series of linear and nonlinear models was tested for predicting bark thickness of radiata pine ( Pinus radiata D. Don) growing in the Australian Capital Territory. A simple linear model proved superior to all other models. This model predicts bark thickness at any point along the bole, relative to bark thickness at breast height, from the fourth power of relative diameter. Relative diameter is defined as the ratio of diameter overbark at a point on the bole to the diameter overbark at breast height. The model is independent of site and age and appears to be unaffected by forest location. Using the model, the underbark volume of 109 trees was estimated to be 54.6 m 3 compared with the actual volume of 54.9 m 3. This represents an error of −0.5%.