Monitoring the water status of Mediterranean forests using ERS-1, to support fire risk prevention

Canopy water content can be useful as an indicator of fire risk, as it affects mainly the vegetation flammability. This paper presents an analysis of terrain corrected multi-temporal ERS SAR data over typical Mediterranean forest covers, which are subject to frequent fires. Despite the small backscatter temporal change of forest covers (typically 0.5 dB up to 1.5 dB) under drought conditions (June to September), backscatter temporal behavior appears to be related to water content changes, as it reaches its minimum in July and August where water content is the lowest. This temporal sensitivity to water content depends on vegetation type in relation with topographic and climatic conditions. Despite interesting experimental results, the analysis of such data is difficult and further quantitative analysis, including modelling will be necessary to assess the potential of ERS SAR data as an information source in fire risk prevention