Spatial convergence and differentiation characteristics of ecological efficiency of forestry carbon sink: Evidence from China

Calculating and analyzing ecological efficiency of forestry carbon sink is key to develop China's forestry carbon sink effectively. This paper utilized super-efficiency stochastic frontier model (SBM) to measure ecological efficiency of forestry carbon sink of 30 provinces (municipalities and autonomous regions) in China from 2000 to 2017. In addition, this study calculated and analyzed convergence trend by constructing β convergence model under consideration of spatial conditions. Study results were revealed as follows. Firstly, ecological efficiency of China's forestry carbon sink presented a "double peak" distribution characteristic of a steady rise with fluctuations. However, overall level was not high, and large room still existed for improvement. Secondly, a significant spatial convergence existed in ecological efficiency of forestry carbon sink in China. Spatial factors had an accelerating effect on convergence trend, making spatial differences in ecological efficiency of forestry carbon sink among regions further narrowed over time. Thirdly, five major forest regions possessed significant spatial convergence, and convergence rates were higher than national average level. The southwest forest region had the highest convergence rate, followed by the northeast, south, northwest and the North China forest regions. Spatial convergence speeds of two periods from 2000 to 2010 and 2011 to 2017 were higher than classical convergence speed, and shown a decreasing change process. Due to existing of spatial convergence, different regions should explore value realization mechanism of forestry carbon sink, clarify regional positioning, and formulate measures based on local conditions to develop forestry carbon sink.