PENDUGAAN BIOMASSA ATAS PERMUKAAN DAN SIMPANAN KARBON PADA TEGAKAN AKASIA (Acacia crassicarpa) DAN EUKALIPTUS (Eucalyptus pellita) DI PT ARARA ABADI

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

Abstrak

This study aimed to estimate stand volume, aboveground biomass, and carbon stock of Eucalyptus pellita on mineral soil and Acacia crassicarpa on peatland at ages 1, 2, and 3 years at PT Arara Abadi, and to analyze differences in those variables across age classes for each species. Data were collected using 36 circular plots with a radius of 11.29 m through DBH and tree height measurements. Volume was estimated using the cylinder formula with a form factor of 0.7, biomass using species-specific allometric equations, and carbon stock was calculated with a conversion factor of 0.47. Eucalyptus pellita volume increased from 171.79; 416.98; to 547.99 m³/ha and Acacia crassicarpa from 132.56; 516.95; to 666.17 m³/ha. Aboveground biomass of Eucalyptus pellita reached 70.49; 188.86; and 246.82 ton/ha, while Acacia crassicarpa reached 31.64; 117.03; and 154.42 ton/ha. Carbon stock of Eucalyptus pellita was 33.13; 88.76; and 116.01 tonC/ha, while Acacia crassicarpa reached 14.87; 55.00; and 72.58 tonC/ha. Welch ANOVA on Acacia crassicarpa and One-Way ANOVA on Eucalyptus pellita showed that age class significantly affected all variables (Sig. < 0.001). Post hoc Games-Howell confirmed all age class pairs in Acacia crassicarpa differed significantly. Tukey HSD confirmed all age class pairs in Eucalyptus pellita differed significantly, except stand volume between ages 2 and 3 years (Sig. = 0.051), indicating a slowdown in diameter increment after canopy closure.