VOLUME PREDICTION FOR MILICIA EXCELSA (WELW C.C. BERG.) TREES IN SELECTED INSTITUTIONS IN IBADAN, OYO STATE, NIGERIA

The study develops equations for the prediction of stem volume of Milicia excelsa  (Welw C.C. Berg.) in some selected institutions in Ibadan, Oyo State, Nigeria. Sequel to the relationship between stem volume (sv), diameter at base (db) and  at breast height (dbh) from enumeration of 61 trees in selected institutions, equations were developed for estimating tree volumes of M. excelsa. Of all the equations developed, logarithmic for volume was the best fit equation containing the db and dbh as the predictors. The equation is lnSV = 1.5924 + 1.4915lndb + 0.8600lndbh with coefficient of determination (R2) and standard error of estimate being 0.9011 and SEE = 0.3485 respectively. Residual analysis revealed that the assumption of independence of residuals is valid, and there is no evidence of an outlier. Validation of the equation was done by testing for significant difference between the predicted stem volume (PSV) and observed stem volume (OSV). The study showed that stem volume of M. excelsa can be predicted from db and dbh by using this equation with reasonable precision. The prediction equation developed in this work would be very useful and applicable where tree dimensions such as diameter at middle and top as well as the height of M. excelsa is difficult to assess and there is need to reduce the cost of inventory of such species.Â