Height-Diameter Predictive Equations for Rubber (Hevea brasilliensis-A. Juss- Muell) Plantation, Choba, Port Harcourt, Nigeria

Abstract

The importance of calibrating models on height-diameter relationship can never be over emphasized in predicting mean total height for trees when only diameter at breast height is measured traditionally. This study has evaluated a set of height-diameter models from twenty plots of Hevea brasilliensis plantation in Choba, Port Harcourt, Nigeria. Non linear techniques were used to develop the functional models with models coefficients derived from 198 sampled standing trees. The predictive models gave a good height - diameter relationship from all the sampled plots in the plantation with coefficients of determination (R²) of strong relationships ranging between 0.62 - 0.98. Many of the resulting models and curves agreed with silvicultural expectation of sigmoidal growth functions; and can provide dependable cum flexible options of predicting heights, given dbh for many plantation species in Nigeria.

Keywords: height-diameter equations, allometric models, predictive equations, sigmoidal curve

Journal of Agriculture and Social Research (JASR) Vol. 11, No. 1, 2011