Book

Climate change in Morocco has intensi ied drought conditions, increased temperatures, and reduced precipitation, signi icantly affecting vegetation dynamics. In the High Atlas, particularly within the M'Goun Geopark, an unprecedented dieback of Aleppo pine (Pinus halepensis Mill.) has been observed. This study aims to quantify this decline and identify its main climatic drivers.Climatic variability was assessed using TX90 and TN90 (extreme temperature days), P10mm, Tmin, Tmax, mean temperatures, the Standardized Precipitation Index (SPI), the Emberger quotient (Q2), and the De Martonne aridity index. Aleppo pine cover changes were analyzed using supervised classi ication of Sentinel-2 imagery (10 m) via Google Earth Engine, and evapotranspiration was used as an indicator of plant water stress.Results show a signi icant increase in temperature-related indices, with an overall rise of approximately 1°C between 1960 and 2020. Precipitation decreased by 77.14 mm, with increased interannual variability conirmed by SPI. Q2 and De Martonne indices indicate a shift from sub-humid to predominantly semi-arid conditions. Aleppo pine forests lost 22 km² (≈40%) between 2015 and 2022. Vegetation decline is strongly correlated with temperature, while precipitation shows no signi icant relationship in August. Evapotranspiration also decreased markedly, indicating increasing water stress.These results highlight climate change as the main driver of Aleppo pine dieback, emphasizing the need for urgent conservation strategies.