Commodity-driven changes in Southeast Asia forest cover and carbon stock using robust visual photo-interpretation

Abstract:

The remaining forests of the global tropics are major stores of carbon for the world. Accurately understanding the drivers of deforestation in developing countries is essential as they continue to grow their economies to meet global consumer needs, improve the welfare of their people, and meet environmental commitments. In Southeast Asia, agricultural development has been a major driver of deforestation over the past 50 years. However, it is difficult to determine which crops have the largest historic and current impact on natural landscapes, particularly forests. Understanding differences in agricultural impact can help countries in Southeast Asia meet environmental commitments and sustainable development goals.

In this session, we describe a USAID-funded study in Southeast Asia that quantified and mapped the extent of commodity-crop driven forest loss between 2000-2015 for 7 countries. We used Collect Earth Online to conduct photo-interpretation to assess forest loss and land use transitions using freely-available moderate-resolution satellite data. Based on our estimate of crop expansion within each forest type, we calculated the associated loss of carbon stocks using regionally-specific carbon stock factors. Across the region, 9.4 million hectares of forest were converted to agriculture, accounting for 59% of the total forest loss. Crops that expanded into previously forested lands include herbaceous crops (2.9 M ha), oil palm (2.4 M ha), miscellaneous other tree crops (1.1 M ha), pulpwood (886,000 ha), and rubber (706,000 ha). However, there were differences in crop expansion composition between countries. These crops collectively stored 269 million tonnes of carbon in above ground biomass, a net reduction of 1.5 billion metric tonnes compared to the forest carbon pool. This analysis provides both the methodological proof of concept and the underlying basis for policy recommendations. Using accurate, science-based accounting methods, including our approach, are necessary for countries to receive payments for conservation arising from agroforestry and other sustainable development actions--and thus provide greater incentive to adopt these sustainable practices.