LEAF-AREA ESTIMATION FROM TREE ALLOMETRICS IN EUCALYPTUS-GLOBULUS PLANTATIONS

Data from five studies on the relationships between dendrometric measu rements and;leaf area of Eucalyptus globulus Labill. plantations were pooled and analyzed to develop regression models for the estimation of leaf area of individual trees. The data, collected at two sites in we st-central and southwestern Portugal, varied in age from 2 to 19 years and in plant density from 481 to 1560 trees/ha and included both firs t and second rotation coppice stands. A total of 29 nonlinear regressi on models were tested and ranked with a multicriteria evaluation (MCE) procedure, based on goodness-of-fit statistics, predictive ability st atistics, and collinearity diagnostics. The best models were validated using an independent data set. The final model selection was based on comparisons of prediction residuals data, statistical tests, and silv icultural and physiological considerations. One model is proposed as a dequate for leaf area estimation of E. globulus plantation trees. This model contains four parameters and independent variables that quantif y stem diameter, crown size, and stand density.