Height-age model and site index curves for Acacia mangium and Eucalyptus pellita in Indonesia

Abstract

Height-age growth models and site index curves were developed for the site quality evaluation of Acacia mangium Willd and Eucalyptus pellita F. Muel stands in Korintiga Hutani plantation, Pangkalan Bun, Central Kalimantan, Indonesia. In this study, the Chapman-Richards growth function was used in the guide curve method to generate anamorphic site index curves for the two species. In order to evaluate the developed models, coefficient of determination (R2), root mean square error (RMSE), bias (), absolute mean difference (AMD), and mean percent bias (MPB) were used as statistical criteria. In addition, a simple linear regression and simultaneous F-test was performed to evaluate the relationship of the observed and the predicted dominant height of each species. Based on the statistical evaluations, simple linear regression and F-test models developed for the two species showed satisfactory results. Furthermore, the developed models explained about 98.35% and 98.60% of the total variation in the estimate of total dominant height for Acacia mangium and Eucalyptus pellita, respectively. The developed site index curves are expected to be significant for forest managers in predicting the growth patterns and classifying the site productivities of the different stands in Korintiga Hutani plantation.

Keywords

• Chapman-Richards function
• dominant height
• site evaluation
• site quality
• tropical forest plantation