Modeling of Teak (Tectona Grandis L.F) Plantation Diameter Distribution in Aramoko Forest Reserve, Ekiti State, Nigeria

Diameter distribution modeling is an essential tool for obtaining reliable information on forest structure, growth, and yield. A diameter distribution model was developed for teak plantations in the Aramoko Forest Reserve. A total of 573 trees were measured in 30 sample plots of 20 x 20 m (0.4 ha) across the entire plantation age classes. The diameter at breast height (dbh) and total height (h) of trees with dbh ≥ 10 cm within the sample plots were measured. Data were analyzed on several probability density functions (pdf) using Easy Fit 5.7 software and then ranked based on the Kolmogorov–Smirnov, Anderson Darling and Chi-Squared. The best six distributions (Beta, Burr, Gamma 4P, Johnson's SB, lognormal, and Weibull (3P) were selected for fitting the diameter data. The results indicated that there are more trees in the lower diameter class than in the upper diameter class. Weibull (3P), Johnson's SB, and Beta distributions with calculated D-values of 0.0266, 0.03209, and 0.0312, respectively, were found to be more flexible when tested with KS Kolmogorov Smirnov. This implies that the data followed the specified distribution and that Weibull (3P) and Johnson SB can appropriately provide a better fit for the diameter data in the Aramoko Forest Reserve teak plantation.