DYNAMIQUE SPATIO-TEMPORELLE DE LA COUVERTURE VEGETALE DANS LA FORET DE CHETTABA

Abstract

Monitoring the intensity of photosynthetic activity in the Chettaba forest is necessary to better understand the distribution and spatio-temporal dynamics of Aleppo pine, including NDVI values at different altitudes, ranging from 774 to 1123 m. This makes it possible to interpret remote sensing data and use GIS to detect changes in the state of vegetation cover. The method adopted is based on 36 Landsat images (TM and OLI/TIRS satellites), forming three scenes 2011, 2014 and 2021; the latter being essentially visual analyzes of images, after eliminating those containing heavy cloud cover. In this study, we analyzed the diachronic evolution of vegetation cover using Normalized Difference Vegetation Index (NDVI) data that took place over a 10-year period (2011 to 2021). Our results reveal variations in NDVI values in the plots studied; the highest average values are obtained in 2011 (0.42) and the lowest are obtained in 2021 (0.28). NDVI maps make it possible to distinguish between different land cover classes. Thus obtained, the temporal profiles of the NDVI allow us to conclude that the Chettaba forest experienced average degradation during the period 2011-2014, and continued degradation during the period 2014-2021. In fact, the low values of this index indicate a poor health status of this forest, and the analysis of the NDVI temporal profile shows that the Chettaba forest has clearly deteriorated in recent years