Satellite Observations of the Recovery of Forests and Grasslands in Western China

Abstract

AbstractThe “Grain for Green” Program (GGP), which combats and reverses the landscape‐scale habitat degradation by converting agricultural lands to forests and grasslands, was launched in 1999 in western China. An assessment of the extent to which the GGP has altered the vegetation cover and ecological functions in these regions is much needed. The present study initially analyzed land use and cover change of forests and grasslands over western China between 2000 and 2015. A variety of satellite‐based ecological indicators, including net primary productivity, normalized difference vegetation index, leaf area index, carbon use efficiency, and water use efficiency, were used to reflect the biophysical consequences of the GGP in western China. Results indicated that the spatial extent of forests and grasslands increased by 13.97 × 103 and 11.13 × 103 km2, respectively, which were mainly converted from deserts and croplands. The ecosystem functions of forests and grasslands showed an asymmetric response in northwestern and southwestern China. The normalized difference vegetation index and water use efficiency of forests, as well as the net primary productivity and water use efficiency of grasslands, increased significantly over this period. The GGP also has led to an increase in leaf area index and carbon use efficiency of forests and grasslands. The Loess Plateau and the Three Rivers Source area represent the most effectively recovered regions in western China. Rising precipitation rates have contributed to vegetation recovery to some extent, especially in northwestern China, whereas the GGP was the prominent reason for the improvement of ecosystem functions across the entire region of western China.