Estimation of total above ground biomass at selected age stands of a rehabilitated forest

Forests have the potential to act as global carbon storage. Due to this, declining forest areas globally elevate the role of remaining natural regenerating and rehabilitated forests. This paper reports an initiative to estimate total above ground biomass distribution and storage at different age stands of a rehabilitated forest. The study site is the UPM-Mitsubishi Forest Rehabilitation Project, Bintulu, Sarawak. 20 x 20m plots were established at one-, 10- and 19- year-old rehabilitated forests and the adjacent natural regenerating secondary forest. Regression analysis showed that the above ground biomass equations with the function of dbh*H have high adjusted coefficient of determination (r^2)= 0.96-0.99. Results showed the distribution of percentage tree component biomass to total above ground biomass was in the order of main stem branch leaf. The total above ground biomass increased significantly with age of the forest which was in the order of Plot 1991 Plot NF Plot 1999 Plot 2008. The total above ground biomass for young rehabilitated forest was estimated at 4.3 x 10^- 3t/plot while the 10 and 19-year-old rehabilitated forests stood at 1.5 t/plot and 4.2 t/plot, respectively, whereas the natural regenerating secondary forest was at 3.9 t/plot. All the study plots showed variations in the total above ground biomass which indicated that these forests are in the process of recovery. The older rehabilitated forest showed comparable total above ground biomass recovery and storage to the adjacent natural regenerating secondary forest. This reaffirms the need for human intervention in rehabilitating former shifting cultivation areas to facilitate the recovery of the above ground biomass.