Forest greenhouse gas emissions estimates in major forest tenure instruments in the Philippines from 2001–2020

Abstract

Forest carbon loss from land use and land cover change is among the major greenhouse gas (GHG) emissions sources, second only to fossil fuel combustion. Determination of updated and spatially consistent forest GHG emissions is vital for countries like the Philippines participating in Reducing Emissions from Deforestation and Forest Degradation Plus (REDD+). This study aims to provide estimates and analyze the trends of forest GHG emissions in three major forest tenure instrument areas in the country, namely the Community Based Forest Management Agreement (CBFMA), Integrated Forest Management Agreement (IFMA), and Mineral Production Sharing Agreement (MPSA). Results showed that these tenure instruments' total forest GHG emissions had a significant and increasing linear trend on a national scale (r_ghge = 0.77, p-value< 0.05), amounting to 29.73 Mt of CO₂e from 2001 to 2020. CARAGA and Zamboanga region provinces exhibited significant forest GHG emissions owing to the vast extent of their concessions and probably forest loss and tree harvesting occurring in their tenure jurisdictions. Interestingly, nickel mining was the only mineral commodity with a linear and robust association with national forest GHG emissions (r_ghge = 0.74, p-value< 0.05). Nonetheless, remote sensing data quality and modeling limitations, overlapping tenure boundaries, inherent data flaws, and various starting and ending dates of tenure holders’ activities should guide the users in interpreting our results. The implications of this study could serve as a basis for reviewing and re-evaluating the tenure instrument agreements and their contribution to forest conservation and climate change mitigation because some agreements are either expiring (e.g., CBFMA) or are open for new tenure applications (e.g., MPSA).