Relationships between stem diameter at breast height (DBH), tree height, crown length, and crown ratio of Vitellaria paradoxa C.F. Gaertn in the Nigerian Guinea Savanna

Abstract

Trees show considerable variation and flexibility in their size of crowns, height and stem diameter at breast height (dbh). Dbh has been used as predictor variables in diameter and height growth equations. Relationships between dbh, tree height, crown length, crown height and crown ratio of Vitellaria paradoxa were investigated and regression prediction models were derived. Dbh, as a predictor variable, was positively correlated with tree height and crown length (F0.05 (1), 8). The correlation coefficients of determination (r²) were 0.447 and 0.399, respectively. The dbh has no correlation with crown height and crown ratio. Here the r² were 0.241 and 0.051, respectively. Stronger correlation was observed when crown length, as a predictor variable, was used against tree height and crown height. The r² values were 0.522 and 0.497, respectively. Hence, regression prediction models derived from this study suggests that the use of crown length as predictor variable is more accurate than the use of dbh in estimating tree height and crown height.

Keywords: Stem diameter, tree height, correlation, regression, Butyrospermum paradoxum, clinometers, minitab

African Journal of Biotechnology Vol. 12(22), pp. 3441-3446