Carbon Budgets of Forest Ecosystems in the Philippines

Forest ecosystems can both be sources and sinks of carbon. Here, we review the state of knowledge on carbon budgets of Philippine forests types. The following are the main findings of the review: Carbon (C) density in aboveground biomass (AGB) declines by about 50% after logging, deforested areas covered with grasses and annual crops have C density less than 15 MgC/ha, conversion of natural forests to tree plantations and perennial crops reduce C density by about 50%, reforestation activities in degraded areas increase C density with a mean annual accumulation of up to about 10 MgC/ha/yr for fast growing species and 3 MgC/ha/yr for slow growing species, and silvicultural treatments such as mycorrhizal inoculation can increase C accumulation. In spite of the new information generated in the last few years, there is still a great need to quantify carbon stocks and rate of sequestration of the various forest types in the country.