Allometric equations to predict the total above-ground biomass of radiata pine trees
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• Radiata pine (Pinus radiata D. Don) is the main exotic plantation tree species grown in New Zealand for wood production and as such represents a significant component of the terrestrial carbon cycle.
• Using data for 637 trees collected in 13 different studies, a series of equations was developed that enable the total above-ground biomass of individual radiata pine trees to be estimated from information about height and diameter. A mixed-effects modelling approach was used when fitting these equations in order to account for random fluctuations in model parameters between studies due to site and methodological differences. Linear models were fitted to logarithmically transformed data, while weighted linear and non-linear models were fitted to data on the original arithmetic scale.
• Based on a modified likelihood statistic (Furnival’s Index of Fit), models fitted to transformed data were found to perform slightly better than weighted models fitted to data on the original arithmetic scale; however, the latter do not require a means for correcting for the bias that occurs when estimates of biomass obtained from transformed models are back transformed to the original scale.
• Recommendations for further development of these models including additional data collection priorities are given.