造林能改善空气污染状况吗?——基于造林存量与流量的实证分析

Can Afforestation Improve the Air Pollution? Based on an Empirical Analysis of the Afforestation Stock and Flow

构建造林存量与流量对空气污染水平的实证模型,先利用时间序列数据,运用格兰杰因果检验分析造林存量、造林流量以及空气污染水平之间是否存在格兰杰因果关系;再利用省级面板数据,运用固定效应模型的分析方法比较分析造林存量与造林流量对空气污染水平的影响以及地区性差异,以探析造林存量与流量对空气污染状况的作用及差异。研究结论有：造林存量与空气污染水平之间存在单项的格兰杰因果关系,而造林流量与空气污染水平之间存在双项的格兰杰因果关系,造林存量与流量之间不存在格兰杰因果关系;造林存量与流量有助于降低空气污染水平,但造林流量比存量对空气污染状况的改善作用更大;造林存量与流量对空气污染状况的影响存在明显的地区性差异,即造林存量对东部地区和中部地区空气污染状况的改善作用更为明显,而造林流量对西部地区空气污染的改善作用更大、更明显。

Using time series data, the paper builds the empirical model on the stock and flow of afforestation to air pollution level, using the granger causality test to analyze the granger causality between air pollution levels and the stock and flow of afforestation. Then by using the provincial panel data, the effect of afforestation stock and afforestation flow on air pollution level and regional difference are compared and analyzed with the method of fixed effect model, so as to analyze the effect and difference of afforestation stock and flow on air pollution. Research conclusions are： The relation between the stock of afforestation and the air pollution levels is one-way granger causality, the relation between the flow of afforestation and air pollution levels is double entry granger causality, the stock and flow of afforestation is no granger causality; The stock and flow of afforestation help to reduce air pollution levels, but the flow of afforestation has more effect on the improvement of the air pollution than the stock of afforestation; The influence on the stock and flow of afforestation to the air pollution exist obvious regional differences, namely, the stock of afforestation to the improvement of the air pollution is more apparent in the eastern and central areas, and the flow of afforestation to improve the air pollution is more and more obvious in the western areas.