Biomass and Carbon Stock Assessment of Trees in the Lowland Evergreen Forest of Mt. Iraya, Batanes, Philippines

The Batanes Protected Landscape and Seascape is one of the key biodiversity areas (KBAs) in the Philippines due to its unique biophysical characteristics. Most of the studies conducted in the area focused on biodiversity assessment and limited data and resources are available on the potential of this area in carbon (C) sequestration. Thus, this study was conducted to assess the potential of trees in Mt. Iraya for C sequestration. Five circular plots were established from 100–300 masl, and five circular plots were also established from 301–500 masl. To determine the aboveground and belowground biomass of each tree, allometric models were used as cutting of trees and excessive trampling activities are strictly prohibited in the protected area. The C was determined using the suggested value in the Philippines, which is 45% of the biomass. Results showed that the total biomass in elevation class I (100–300 masl) is 1036.74 Mg ha–1, whereas it is 1422.68 Mg ha–1 in elevation class II (301–500 masl). Furthermore, the C and CO2 sequestered in elevation class I is 466.53 MgC ha–1 and 1712.17 MgCO2e ha–1, respectively, whereas the C sequestered in the elevation class II is 640.21 Mg ha–1 and 2349.56 Mg ha–1 for CO2. The biomass density in Mt. Iraya is higher compared to other forest ecosystems in the Philippines. This only shows that the forest in Mt. Iraya must be protected to further enhance its potential as a C sink rather than the source of emission.