Public policies and global forest conservation: Empirical evidence from national borders
利用高分辨率遥感数据和两种因果推断方法，研究发现国家边界两侧森林状况存在显著差异，公共政策使全球树木覆盖损失风险降低近4个百分点，且政策执行力度、严格程度、产权和法治是影响效果的关键因素。
Protecting the world’s remaining forests is a global policy priority. Even though the value of the world’s remaining forests is global in nature, much of the protection has to come from national policies. Here, we combine global, high resolution remote sensing data on forest outcomes (tree-cover loss, forest degradation, net primary production) and two complementary econometric research designs for causal inference to first quantify how much it matters in which country a forest is located, secondly, the role of public policies, and third, under which conditions such pubic policies tend to be most successful. We find considerable border discontinuities in remotely sensed forest outcomes around the world (in a regression discontinuity design) and these are largely explained by countries’ policies (using a differences-in-discontinuities design). We estimate that public policies reduce the risk of tree cover loss by almost 4 percentage points globally, but there is large variation around this. The best explanations we find for these heterogenous treatment effects are a country’s policy enforcement, its policy stringency, its property rights, and its rule of law (in that order). Our results motivate international cooperation to finance and improve (a) countries’ public policies for forest protection and (b) countries’ capacity to implement and enforce them well.