Evaluating the effect of plain afforestation project and future spatial suitability in Beijing

Taking the"One Million-Mu(666 km^2)"Plain Afforestation(PhaseⅠ)Project(Phase I afforestation)in Beijing city as an example,we monitored the growth status of planted forest using long-term remote sensing images,and evaluated the impacts of afforestation on land use change and vegetation growth.We found there is a large space for improvement regarding the ecological benefits of the project.Moreover,we found forest patches with decreasing greenness after the afforestation were mainly converted from farmland with high greenness and low heterogeneity in terms of the normalized difference vegetation index(NDVI).This implies that those farmland patches are inappropriate for afforestation.According to the results from PhaseⅠafforestation and the impact of urbanization on green space,we constructed a series of spatial variables and generated a suitability map for the next"New Round of One Million-Mu(666 km^2)Afforestation project"(PhaseⅡafforestation).We then modeled the spatial distribution of PhaseⅡafforestation based on the derived suitability map.This study is crucial for the scientific evaluation of afforestation projects for space planning(e.g.,urban green space planning).The evaluation and modeling framework built in this study can be used to support the decision making and policy implementation of afforestation projects in China.