SPATIAL ANALYSIS OF FOREST REGENERATION AFTER FIRE IN THE FOREST OF FERGOUG IN MASCARA, ALGERIA

Forest fires have become frequent in Algeria in the last couple of years, causing severe damage to flora and fauna. Conditions for natural regeneration are not always favourable. This study makes a post-fire assessment of the burned area in the forest of Fergoug in Mascara, western Algeria, which was ravaged by a large fire in 2003. We highlight the use made of remote sensing tools and their integration with a geographic information system (GIS). The study used data from Landsat-TM (October 1987), ALSAT-1 (August 2003 and October 2007) with data products from the ASTER satellite's digital terrain model. Through a GIS analysis combining normalized difference vegetation indexes (NDVI) generated from satellite imagery with other data layers (forest maps, exposure maps, limits of burned areas, etc.), we were able to map changes in the study zone after the fire. The results, validated against ground-truth data, show remarkable natural regeneration in some local species, especially the Tetraclinis articulata thuya. Regeneration is much more evident on fairly gradual north-facing slopes: these are less exposed to summer heat and consequently store more soil moisture, which is essential to vegetation growth. Much less regeneration was observed on the southern and western slopes. The statistics produced indicate that areas with tree cover before the fire are now occupied by sparse matorral and maquis vegetation, which, if adequately protected and maintained, could quickly recover to reform the tree cover observed before the fire.