Carbon Stock Estimation of Selected Watersheds in Laguna, Philippines Using InVEST
Jan Joseph Dida, Cristino Tiburan, Narumasa Tsutsumida, Izuru Saizen
Abstract
Carbon sequestration is one of the most important forest ecosystem functions that has been recognized globally but the dynamics are highly influenced by the alteration of forest cover. Given the different development thrusts in the Laguna province, the estimation and monitoring of carbon storage become an important activity. This study aims to estimate the carbon stock in the Silang-Santa Rosa and Pagsanjan-Lumban watersheds and explore the possible changes as an effect of land use changes. Sentinel-2 and Landsat 5 satellite images covering different time periods were classified to generate the land use maps. The process of carbon stock estimation was implemented using the carbon storage and sequestration model of Integrated Valuation and Ecosystem Services and Tradeoffs (InVEST) software. Carbon pool data for the land uses were obtained from different studies and estimates. Classified images covering different time periods showed that the largest land uses among the different land uses in the selected watersheds are built-up and agriculture. Much of the carbon stock was attributed to the high carbon pool values of the forest class. The reduction of forest areas in the watersheds resulted in a decrease in the total carbon stock. The generated land use scenario showing the continued built-up and agriculture expansion decreased the carbon stock further. The estimation of carbon stock based on different land use change scenarios will help in the evaluation and planning of future land use.