PENDUGAAN BIOMASSA ATAS PERMUKAAN DAN SIMPANAN KARBON ACACIA CRASSICARPA DAN EUCALYPTUS PELLITA DI AREAL HUTAN TANAMAN INDUSTRI

Estimation of Aboveground Biomass and Carbon Stock of Acacia crassicarpa and Eucalyptus pellita in Industrial Plantation Forest Areas

Abstract

This study aimed to estimate stand volume, aboveground biomass (AGB), and carbon stock of Acacia crassicarpa on peatland and Eucalyptus pellita on mineral soil at ages 1, 2, and 3 years at PT Arara Abadi, and to analyze differences across ages within each species. Data were collected from 36 circular plots (radius 11.29 m) by measuring DBH and tree height. Volume was estimated using the cylinder formula with a form factor of 0.7, AGB using species-specific allometric equations, and carbon stock using a conversion factor of 0.47. The mean volume of A. crassicarpa increased from 22.08 to 86.07 and 110.96 m³/ha, with AGB of 10.55, 39.01, and 51.48 ton/ha and carbon stock of 4.96, 18.33, and 24.20 tonC/ha. The mean volume of E. pellita increased from 28.56 to 74.43 and 91.28 m³/ha, with AGB of 23.50, 62.95, and 82.28 ton/ha and carbon stock of 11.04, 29.59, and 38.67 tonC/ha. Because variances were heterogeneous for A. crassicarpa, Welch ANOVA with the Games-Howell test was applied, whereas One-Way ANOVA with Tukey HSD was used for E. pellita. Age significantly affected all variables in both species (Sig. < 0.001). All age pairs differed significantly, except stand volume between ages 2 and 3 years in E. pellita (Sig. = 0.051). Each species used a different allometric model on a different site type, so comparisons were made within each species across ages.