Analyse de la dynamique des massifs forestiers de l’Est algérien par la télédétection satellitaire

Abstract

The main objective of this work is to determine the trend of the vegetative activity of the forests of eastern Algeria from the processing of a series of MODIS satellite images type of medium resolution (250m) over 10 years (2002- 2011). These allow us to track the status of forest vegetation of eastern Algeria through the vegetation index which is defined as the normalized difference spectral reflectance measurements acquired in the wavelength areas Near Infra -Red and red. The Maps from this contribution we have to identify 19418 pixels that tend toward regression with 3282 pixels are displayed at the wilaya of El Tarf, representing 17% of all degraded forest massifs and 1.2 % of the total forest cover of eastern Algeria. Among the studied forest ecosystems, cork oak seems the essence most threatened by degradation with a significant area of 64425ha, more than half (53.08%) regressed the surface are occupied by the species. It is followed by the Aleppo pine with 29287,5ha or 24.13% of total regressed surfaces. In conclusion, the maps from this study are alarming regional picture of the evolution of forest vegetation in eastern Algeria during the decade (2002-2011), which requires a comprehensive and multidisciplinary study of these ecosystems foresters to better determine the environmental factors (biotic or abiotic) responsible for this notable degradation