remote sensing Article Tracking Reforestation in the Loess Plateau, China after the “Grain for Green” Project through Integrating PALSAR and Landsat Imagery Hui Zhou 1,2, Fu Xu 1,*, Jinwei Dong 2 , Zhiqi Yang 2, Guosong Zhao 2 , Jun Zhai 3, Yuanwei Qin 4 and Xiangming Xiao 4 1 School of Information Science and Technology, Beijing Forestry University, Beijing 100083, China;
[email protected] 2 Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
[email protected] (J.D.);
[email protected] (Z.Y.);
[email protected] (G.Z.) 3 Satellite Environment Center, Ministry of Ecology and Environment, Beijing 100094, China;
[email protected] 4 Department of Microbiology and Plant Biology, Center for Spatial Analysis, University of Oklahoma, Norman, OK 73019-0390, USA;
[email protected] (Y.Q.);
[email protected] (X.X.) * Correspondence:
[email protected]; Tel.: +86-010-62336230 Received: 30 September 2019; Accepted: 14 November 2019; Published: 17 November 2019 Abstract: An unprecedented reforestation process happened in the Loess Plateau, China due to the ecological restoration project ‘Grain for Green Project’, which has affected regional carbon and water cycles as well as brought climate feedbacks. Accurately mapping the area and spatial distribution of emerged forests in the Loess Plateau over time is essential for forest management but a very challenging task. Here we investigated the changes of forests in the Loess Plateau after the forest reconstruction project. First, we used a pixel and rule-based algorithm to identify and map the annual forests from 2007 to 2017 in the Loess Plateau by integrating 30 m Landsat data and 25 m resolution PALSAR data in this study.