MONITORING FIRES IN AREAS CHARACTERIZED BY GRAZING PRESSURE

Fire is widely recognized as a factor of deforestation and land degradation in the Mediterranean basino Mediterranean vegetation is provided with different mechanisms for resisting fire; the limiting faetor is constituted by fire frequeney whieh ean transforrn fire from ecological faetor into destruetive faetor. The present paper deals with monitoring of affeeted surfaees in order to inventory areas threatened by desertifieation because of the high fire frequency. Remote sensed data (Landsat TM) were used to monitor land cover changes due to forest fires in two test areas in Sardinia, an Italian region where fire has historically played an important role and is closely related to agropastoral activities. The application of standardized digitaI change detection techniques (multitemporal vegetation index difference, supervised classification on multitemporal bands or principal components cxtractcù from a set of multitcmporal TM bands) has sho\vn a high classification accuracy in burnt areas inventorying (>93%). The applieation of simple digitaI change detection techniques to satellite data on different test areas provided high aeeuraey in burnt areas inventorying thus assuring an operational use of sueh teehniques