Allometric Equation and Carbon Sequestration of Acacia mangium Willd. in Coal Mining Reclamation Areas

Abstract

The largest part of carbon exchange (CO₂ and CO) between the atmosphere and the land occurred in the forest because forest vegetation to absorb carbon through photosynthesis to build the other half of woody biomass is carbon compounds. Thus, the status of forest management will determine whether the land acts as a source of emissions (source) or sinks (sinks) of carbon. The amount of organic matter stored in forest biomass per unit area and per unit time is the subject of forest productivity. Forest productivity is a picture of the ability of forests to reduce CO₂ emissions in the atmosphere through physiological activity. Measuring productivity of forests in the context of this study is relevant to biomass measurements. Forest biomass provides important information in the assumed magnitude of potential CO₂ sequestration and biomass in a certain age that can be use to estimate forest productivity.

Tree biomass accumulations and age-related changes of A. mangium plantations were determined using a destructive sampling technique. These data were used to estimate optimum harvesting time. Tree biomass samples were collected in 3, 5, and 7 year old plantations in mined area, and in 7 year old plantations in not mined area.

Allometric equations were developed for each site to estimate root, stem, branch, leaf, aboveground and total biomass and stem volume. Using these equations, the stem volume and biomass of each component for each stand age were estimated. A single allometric relationship for all sites was found just for estimation of biomass and stem volume. Allometric expressions of diameter breast height and stem volume for A.mangium stand is Y = 0,000004 X ^2.7126 R² = 0.9838; and the relationship beetween diameter breast height with tree biomass for A.mangium, where allometric equation for stem is Y = 0.4668 X ^1.8287 with correlation coefficient (R² ) = 0.9855. For the branches is Y = 0.078 X ^2.0038,  with correlation coefficient (R² ) = 0.9542 , and for the leaf is Y = 0.0648 X ^1.9348 with correlation coefficient (R² ) = 0.9502. The contribution of stem, branch and leaf biomass of  A.mangium were 67%, 19% and 14% repectively.

Keywords: reclamation, coal minning, carbon sequestration, mulawarman university, allometric, CO₂