Monitoring of forest cover dynamics in eastern area of Béni-Mellal Province using ASTER and Sentinel-2A multispectral data

This study aimed to monitor and analyze the spatial and temporal dynamic of forest cover in Eastern area of Beni-Mellal Province (Morocco), using multispectral ASTER and Sentinel-2A MIS images acquired in 2001 and 2015, respectively. The supervised classification algorithm and NDVI were combined within a GIS environment to quantify the extent and density change of forest cover stands, i.e., Holm oak, Aleppo pine, Thya, Zea oak, Crops & others and Bare ground. The classification overall accuracy was 97.76 and 95.80% in 2001 and 2015 images, respectively. The result revealed an overall forest cover change with an increase in forested area. All species stands showed expansion at the expense of the bare ground and crops & others classes. The density maps showed a net density change with an expansion of dense forest class. The observed forest cover expansion may be due to the favourable climate in the examined period, the protection, the reforestation programs and the regeneration through clandestine cutting. These results constituted the first attempt at mapping and monitoring of forest cover change in the study region that used a remote sensing-based product. They will help authorities and forest managers for the development of sustainable forest conservation and management decisions.

本研究旨在监测并分析摩洛哥贝尼梅拉尔省东部区域的森林覆盖时空动态变化，分别采用2001年与2015年获取的多光谱ASTER及Sentinel-2A MIS遥感影像。在地理信息系统（Geographic Information System，GIS）环境下，将监督分类算法与归一化植被指数（NDVI）相结合，以量化研究区内森林覆盖斑块的面积与密度变化，涵盖冬青栎、阿勒颇松、Thya、泽亚栎、耕地及其他类型与裸地。2001年与2015年影像的分类总体精度分别为97.76%与95.80%。研究结果显示，整体森林覆盖发生变化，林区总面积呈增长态势。所有树种斑块均以牺牲裸地与耕地及其他类型为代价实现扩张。密度分布图表明，密林斑块呈现净扩张趋势。本次观测到的森林覆盖扩张，可能源于研究时段内的有利气候条件、保护举措、造林计划以及非法采伐后的自然更新。本研究成果是该区域首次采用遥感产品开展森林覆盖变化制图与监测的尝试，可为相关主管部门与森林管理者制定可持续森林保护与管理决策提供参考支撑。