长期以来，建设固沙林被认为是沙漠化防治和沙地生态系统恢复的最基本途径；我国营造固沙林历史悠久，是世界上固沙林面积最大的国家。然而，随着社会和科学技术的不断发展，固沙林在控制沙漠化和恢复沙地生态系统中的作用受到社会各界的广泛质疑。因此，明确固沙林在历史时期的变化动态，并确定其控制沙漠化的作用和机制是决定干旱、半干旱沙区固沙林是否继续建设以及如何建设的关键。本项目以固沙林建设核心区—科尔沁沙地为研究区，利用地面调查、定点监测与多源遥感数据（高光谱、高分影像等）相结合方法，明确科尔沁沙地53年来（1964~2017年）固沙林（包括数量和林分结构）变化动态及对应的沙漠化过程；探讨林分/景观尺度固沙林和关键环境要素与沙漠化的相互作用机制；确定固沙林控制沙漠化的贡献率，揭示固沙林存在的问题并寻求解决策略。研究结果可为干旱、半干旱沙区固沙林建设布局与经营管理，以及沙漠化控制提供理论与技术支撑。

The construction of sand-fixing forests is considered to be the most efficient way to control desertification and restore sandy ecosystem for a long time. China has a long history of planting sand-fixing forests, and becomes the largest areas of afforestation in the world. However, with the development of society and continually progress of science and technology, the effect of sand-fixing forests on desertification control and sandy ecosystem restoration has been widely questioned. Therefore, it is necessary to elucidate the spatial-temporal changes of sand-fixation forests and the mechanism of sand-fixation forests on desertification. Then we can determine whether the sand-fixing forests can continue to be constructed and how to build it in the arid and semi-arid sandy regions. Thus, the Horqin Sandy Land of the Northeast China as the core construction region was selected as research areas for this project. Based on the field investigations and multi-source remote sensing data (including high-resolution satellite imagery and hyperspectral remote sensing data), the specific objectives of this project are as follows: 1) to explicit the spatial-temporal patterns of sand-fixation forests (including stand structure of sand-fixation forests) and desertification from 1964 to 2017; 2) to explore the interaction mechanism of stand structure of sand-fixing forests, key environmental factors and desertification at stand and landscape scales; 3) to determine the role of sand-fixing forests in desertification; and 4) to reveal of the problems of sand-fixing forests and to seek solutions approach. The results obtained in this project will have both important theoretical and practical significances for controlling desertification and providing the plan about construction and management of sand-fixing forests in the arid and semi-arid sandy zones.