中国林业碳汇效率时空演化特征——基于三阶段超效率数据包络分析模型

Spatio-temporal evolutionary characteristics of forestry carbon sink efficiency in China based on a three-stage super-efficiency SBM-DEA model

提高林业碳汇效率是缓解气候变化、实现碳中和的重要路径。客观评价我国林业碳汇效率及其时空演化特征,有助于加快国土空间绿化进程。采用三阶段超效率SBM-DEA模型对中国30个省(市、区)2008—2021年林业碳汇效率进行测度,并运用GML指数、Moran′s I指数和空间马尔科夫链等方法对林业碳汇效率的变化规律及时空演化特征进行分析。研究发现:(1)中国林业碳汇效率总体水平不高,不同地区间差异明显;四大林区林业碳汇效率呈现“西南林区>东北林区>南方林区>北方林区”的空间分异格局;剔除外部环境和随机误差的影响后,低效率地区呈现出“追赶”高效率地区的趋势。(2)林业碳汇效率变化呈上升趋势,其中GML指数最高的地区为东北林区、最低的为北方林区;技术进步对林业碳汇效率提升的贡献较大,不同地区对综合效率的依赖程度不同。(3)林业碳汇效率具有空间非均衡性,高效率地区与低效率地区间呈现“包围状”分布,且该特征在时间上保持稳定;2015年后林业碳汇效率存在显著空间正相关性,空间分布存在聚集效应;考虑空间滞后项的空间马尔可夫链结果表明,邻域类型对林业碳汇效率状态转移影响显著,空间分布上具有较强的近邻效应,呈现“高高趋同,低低趋同,高带动低,低抑制高”的空间演化特征。研究对提升生态系统碳汇能力与建设人与自然和谐共生的现代化具有重要现实意义。

There exists a significant pathway in mitigating climate change and achieving carbon neutrality,which is to enhance the efficiency of forestry carbon sink.An objective evaluation of China′s forestry carbon sink efficiency and its spatio-temporal evolutionary characteristics plays a crucial role in speeding up the process of national land greening.The three-stage super-efficiency SBM-DEA model was used to estimate forestry carbon sink efficiency in 30 provinces(municipalities and districts)in China from 2008 to 2021.At the same time,in order to find out the change rules and spatio-temporal evolutionary characteristics of forestry carbon sink efficiency,we used the methods of GML index,global Moran index and spatial Markov chain to carry out detailed analysis.The results revealed that:(1)In general,the level of forestry carbon sink efficiency in China was not high,which had great room for improvement.The difference of forestry carbon sink efficiency among different regions was also very obvious.The spatial pattern of forestry carbon sink efficiency in four forest regions was Southwest Forest region>Northeast forest region>Southern forest region>Northern forest region.After eliminating the influence of external environment and random error,the low efficiency regions showed a trend of catching up with the high efficiency regions.(2)The change of forestry carbon sink efficiency showed an upward trend,and the region with the highest GML index was the northeast forest region and the lowest was the northern forest region.Technological progress had a great contribution to the improvement of forestry carbon sink efficiency,and different regions had different dependence on comprehensive efficiency.(3)The efficiency of forestry carbon sink was spatially non-equilibrium,with a“bounding”distribution between high-efficiency regions and low-efficiency regions,and this feature remains stable in time.After 2015,there was a significant spatial positive correlation between forestry carbon sink efficiency,and the spatial distribution had a clustering effect.The results of the spatial Markov chain considering the spatial lag term indicated that the neighborhood type had a significant impact on the state transition of forestry carbon sink efficiency,and there was a strong neighbor effect in the spatial distribution,showing the spatial evolution characteristics of“high and high convergence,low and low convergence,high drive low,low inhibition high”.The research is of great practical significance for enhancing the carbon sink capacity of forest ecosystem and constructing the modernization of harmonious coexistence between man and nature.