Carbon dioxide (CO2) storage and sequestration of land cover in the Leyte Geothermal Reservation

This study estimated the existing stored carbon (C) and rate of sequestration by vegetation that can potentially serve as a sink for the carbon dioxide emitted from eight geothermal plants in Leyte Geothermal Reservation, Philippines. For the 20,438 ha watershed in the vicinity of the power project, the total C storage is 3.84 Mt C (14.10 Mt CO2) While C sequestration based on biomass chan-e was 47.35 kt C (173.77 kt CO2). Relative to power plant emission, the C stored in the reserve is equivalent to more than 22 years of CO2 emission. Annual C sequestration is 27% Of CO2 emission per year. For the next 25 years, two scenarios were projected. Under Scenario I ("Business as Usual"), the forest reserve will be able to store and sequester more than 32 years of CO, emission from the power plants. Under Scenario II ("Accelerated Reforestation"), the reserve will be able to store and sequester about 34 years of CO2 emission. In addition, the rate of C sequestration based on biomass change in vegetation was recorded to assess the optimum land use that can absorb the carbon dioxide emitted by the power project. These are as follows: tree plantations (10.09 tC/ha/yr) > coconut (4.78 tC/ha/yr)> brushland (4.29 tC/ha/yr) > natural forest (0.92 tC/ha/yr). In terms of cost, the power project operator is spending P1.22 per t CO2 (P4.4 or US$0.12 per tC) for every year of C storage and sequestration. For 25 years, the total cost is P30.40 per tCO(2) (P111.5 or US$2.94 per tC) which is comparable to the cost of C offset in other tropical countries. (C) 2001 Elsevier Science Ltd. All rights reserved.