This study characterized one of the Mediterranean ecosystems, which is the Natural Reserve of Beni Salah (located in the North East of Algeria in province of Guelma), from the vegetation and climate points of view. The link between these two parameters was also studied using meteorological data and satellite imagery in the period from 1986 to 2015. For this reason, the homogeneity of temperature series was tested using Standard Normal Homogeneity, Pettitt ; Buishand and Von Neumann tests. The Mann-Kendall trend test and Sen’s slope were applied to test the trends and changes over a long period of maximum, minimum and mean temperature data. Also, the vegetation was analyzed through the calculation of the normalized difference vegetation index (NDVI) from satellite images of Landsat. The obtained results showed the important inhomogeneous structure for the months of April and July in 1999 and 2000; respectively. It was found that maximum temperature presented positive Kendall’s value which indicated an increasing trend over the time, with the significant warming of 0.11 °C for the spring season. Over the years, the diachronic of the vegetation productivity (NDVI) varied from a type of formation to another with a peak values in forest formation (zeen oak and cork oak), while a decrease was observed from year to year in this formation corresponding to stressed vegetation. The strong negative correlation between NDVI and the maximum of temperature was observed, which indicated that the warming had a great impact on forest formation productivity, leading to changes in plant physiological processes.