Mapping Deforestation and Land Cover Conversion at the Rainforest Margin in Central Sulawesi, Indonesia

The tropical rain forests in Indonesia are affected by socio-economic and ecological factors and processes that result in an increasing destabilisation of the rainforest margins. Optical satellite data have been explored to document changes in land cover throughout the past 30 years and to monitor the current status and dynamics of land cover and land cover conversion for an investigation area of 7,500 km in Central Sulawesi. The purpose of the study is to evaluate available satellite data sets and to establish a transparent work flow for the monitoring of past and future land cover dynamics at a regional scale based on medium resolution satellite data. This includes rigorous radiometric calibration as well as advanced classification techniques. A time series of Landsat data (Landsat/MSS; Landsat/ETM+) have been radiometrically processed including sensor calibration, atmospheric correction (COST-model) as well as the correction of solar and topographic illumination effects. Land cover mapping has been performed using a comprehensive, context-based approach including image segmentation, fuzzy logic based class definitions (rule sets) and classification. Results of the change analysis show that forest degradation and deforestation within the study area in Central Sulawesi is occurring but at a significantly lower rate (-0.6%/year) than for the rest of the Indonesian Archipelago (-1.2%/year). Nevertheless, deforestation in Central Sulawesi has dramatically increased during the past few years, mostly due to illegal clear-cut logging which shows severe impacts on the environment (i.e. floods, landslides).