Tree stem taper (shape) models are fundamental components of plantation growth and yield modelling systems. A new, two-stage, taper model for Eucalyptus globulus plantations across southern Australia was developed using data of stem diameters under bark at successive heights along the stem for 2,205 Eucalyptus globulus Labill. trees aged 4–30 years. The model requires measurement only of stem age, height and diameter at breast height over bark. Various site, silvicultural and climatic variables did not seem to improve appreciably the fit to the data of the model. The model may be used to predict wood volume between any two chosen heights or under bark diameters along individual stems of trees. With 95% certainty, it was found that volume estimates of the entire stem, or sections within it, tended to be slight over-estimates, lying within the range 0.3−1.3% of the true volume.
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Stem taper model for individual trees of Eucalyptus globulus in Australian plantations