Pendugaan Produktivitas Kopal Berdasarkan Beberapa Peubah Fenotipe Pohon Agatis (Agathis loranthifolia Salisb) di Hutan Pendidikan Gunung Walat

Abstract

The selection process of getting agathis trees of copal leaks takes a long time. Therefore, a quick method is needed to estimate trees of copal leaks based on the phenotype variables of trees. This study was aimed to produce a model of estimating copal productivity and explain the relationship between productivity levels and some phenotype variables of trees, and between the tree phenotype variables. The study used a multiple linear regression analysis with four phenotype variables: stem diameter, bark thickness, height and canopy volume. The analysis obtained the best model with ŷ = –1.445 + 6.072x1 + 0.016x2 + e with R2 = 49.3%, x1 = bark thickness and x2 = canopy volume. Copal productivity had a very significant strong positive correlation with canopy volume (r = 0.601), a very significant medium positive correlation with stem diameter (r = 0.550) and bark thickness (r = 0.469), and a significant low positive correlation with total height (r = 0.355). Stem diameter had a highly significant medium positive correlation with bark thickness (r = 0.594), total height (r = 0.478) and canopy volume (r = 0.470). Bark thickness had insignificant low positive correlation with height (r = 0.209) and canopy volume (r = 0.189). Tree height had a highly significant positive correlation with canopy volume (r = 0.628).