MODELLING TREE DIAMETER GROWTH OF PLANTATION GROWN <em>DRYOBALANOPS</em> <em>SUMATRENSIS</em>

Abstract

AHMAD ZUHAIDI, Y. 2006. Modelling tree diameter growth of plantation grown Dryobalanops sumatrensis.
This paper examines the diameter growth of planted Dryobalanops sumatrensis based on the results of
measurements for all trees with diameter ≥ 10 cm collected between 1997 and 2000. The study was carried
out at Bukit Lagong Forest Reserve, Selangor, Peninsular Malaysia. Least square method using transformed
and weighted models was developed to relate periodic annual diameter increment to diameter, competition
indices and environmental factors as independent variables. The results indicated that transformed model
relating periodic annual diameter increment to diameter, competition indices (basal area and over-topping
basal area) and environmental variables (elevation and slope) explained a significant proportion of the
variation in the periodic annual diameter increment at 36.7% (p < 0.05). Overall results of the modelling
were negatively biased and underestimated the predicted periodic annual diameter increments of the
species.