TREE COVER CLEARANCE MONITORING IN THE PEATLANDS OF INSULAR SOUTHEAST ASIA WITH DUAL POLARIZED SAR DATA

摘要

Southeast Asian peatland areas continuously experience extensive tree cover clearance activities both in the form of deforestation of natural forests as well as harvesting of pulp wood plantations (mainly Acacia). Monitoring of these changes is important for peatland management purposes. In this paper we present a concept and preliminary tests on tree cover clearance monitoring in peatland areas with a combination of existing land cover map and dual polarized synthetic aperture radar (SAR) data. We highlight the sensitivity of Sentinel-1 C-band VH backscatter to tree cover clearance and utilize simple thresholding in bi-monthly time series analysis to map tree cover clearance within our study areas from May 2015 to June 2016. The detected changes are then overlaid with existing land cover map to separate deforestation of natural forests from tree cover clearance in industrial plantation. The preliminary results indicate that the tested approach will enable frequent and reliable monitoring of plantation harvesting cycles and clearance of natural forest for land cover conversion. However, due to incomplete destruction of forests during forest fires, the total extent of forest areas destroyed by fire activity cannot be accurately derived with the tested method.