| 英文摘要： |
The large-scale greening observed across China in recent decades has been shown to be the result of human activities, and existing studies have also revealed the positive effects of policies on vegetation dynamics. However, the effects and mechanisms of detailed greening policies in China still remain unclear and targeted analyses are needed to offer scientific guidance for further policymaking in the pursuit of nationwide green development. In this study, Sen?s trend estimator and the Mann?Kendall test were used to analyze the spatiotemporal changes in vegetation cover from 2000 to 2015. The effects of five main government policies on vegetation cover (i.e., afforestation, urban greening, agricultural improvement, nature reserve, and natural forest conservation policies) were investigated by using Kendall?s tau-b correlation, as well as buffer zones and fluctuation analyses model. The results showed that China has experienced large-scale greening, despite the local degradation of vegetation in some areas. Policy-driven afforestation has played an important role in large-scale greening, while policies related to agricultural intensification have enhanced vegetation cover. Although urbanization has altered local ecosystems, the relationship between changes in vegetation cover and urban sprawl displayed a ?U-shaped? curve, which indicates that urban greening policies have been effective. National nature reserve policies and the National Forest Conservation Program have provided the stable conditions needed for natural vegetation growth without negative human disturbance. It may be concluded that government policies have had a clear and positive influence on greening in China in many respects. |
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