SUMMARY
From this study, we found out that the Weibull distribution was best suitable for the teak plantation in the University of Benin. When compared to previous studies, this distribution was found to be more accurate and applicable for predicting height-diameter relationship. However, height-diameter relationship varies within a region, depending on local environmental conditions (Huang 1999, Huang et al. 2000). The models used in this study do not take into account the effects of climatic and ecological factors on height-diameter relationships within different ecological sites. Hence further development of ecoregion-based individual tree height-diameter models is critical for accurate models on which to base forest management decisions (Huang 1999, Huang et al. 2000).
Regression models for volume estimation were also developed and validated for Tectona grandis plantation in the University of Benin. The tree data was collected from temporary sample plots in the study area. Based on the models examined in this study, the best models chosen for this study were equations 3 and equations 2 respectively considering the parameter validity and fit statistics. Thus, these equations and parameter estimates are notably practical for stand volume prediction of Tectona grandis plantation especially in the University of Benin, Edo state. Evans (1992) stated that many tropical countries afforestation programs tends to emphasizeplantation establishment and neglecting subsequent silvicultural management decision.
Chapman-Richards, Schnute and Logistics models explained over 90% of the total variance in their corresponding response variables for fit data sets. Based on statistical criteria (R2, RMSE, BIC and AIC), tests for normality of residuals, and examinations of residual plots, the regression models developed (Chapman-Richards and Weibull) were suitable for predicting This study will help promote a basis for further investigations on relationship between volume and other growth parameters. Thus, all models in this study with good fit are recommended for tree volume estimation of Tectona grandis plantation in the University of Benin, Edo state. Nigeria.
their corresponding response variables in the study area.
