Prediction equations for estimating tree height, crown diameter, crown height and crown ratio of Parkia biglobosa in the Nigerian guinea savanna

摘要

Relationships between stem diameter, tree height, crown diameter, crown height and crown ratio of?Parkia biglobosa?were investigated and regression prediction models were derived. The result revealed positive correlations between stem diameter, tree height, crown height and crown diameter which are significant. The corresponding F-values from analyses of variance are also significant (P=0.05), except for stem diameter with crown ratio, which show no relationship. The values of Pearson correlation coefficients (r) between the stem diameter and tree height, crown height and crown diameter are 0.825, 0.846 and 0.846, respectively. The corresponding coefficients of determination (r2) are 0.680, 0.715 and 0.767, respectively. This means that 68% of tree height, 71% of crown diameter and 76% of crown height were accounted for by the stem diameter. Taking the crown diameter as a predictor variable, there were also positive correlations with tree height and crown height. Here the r- values were 0.728 and 0.776 and the r2- values were 0.529 and 0.602 respectively. These show that stronger correlations were found with tree height and crown height when the stem diameter was taken as predictor variable than crown diameter.