Carbon sequestration potential of the secondary growth forest along the Abuan watershed at Ilagan, Isabela

Abstract

The Abuan watershed had experienced deforestation due to illegal deforestation, poaching and land conversion. This has resulted to the loss of its ecosystem services. In the watershed area, restoration efforts showed encouraging results where secondary forest is flourishing. Secondary forest growth provides tremendous potential for large amounts of carbon sequestration.This study aimed to determine the carbon sequestration potential of the secondary growth forest along Abuan watershed in Ilagan, Isabela. Specifically, it was conducted to identify the tree species present in the area and estimate the amount of carbon sequestered annually by the above ground carbon cover of the trees in the study area. Ten (10) sampling points measuring 20m x 20m were established using Point center quarter method (PCQM). Tree census was conducted and identification was done up to its species level. The amount of carbon sequestered by the trees was measured.Twenty six (26) species was documented. The above ground carbon by the trees in the watershed is calculated at 18,452 kg. The species Shorea concorta (White lauan) has the highest amount of carbon sequestered while Dipterocarpus validus (Hagakhak) species sequestered the lowest. The age, height and DBH are directly proportional to the amount of carbon sequestration. Thus, the younger the tree, the higher the amount of carbon sequestered and the older the tree, the lower the amount of carbon sequestration. In addition, the taller and wider the tree, the higher carbon sequestration potential per year. It is recommended that below ground potential including the carbon-sink function of the soil be included in estimating the carbon sequestration potential of the secondary growth forest to understand fully this ecosystem function.