Spatiotemporal carbon sequestration by forests among counties and grids in China

Abstract

Top-down emission reduction target setting results in inability of local governments to develop differentiated plans for emission reduction. Forests have received considerable attention as an important source of carbon sequestration, especially following China's commitment to carbon neutrality. However, studies have paid little attention to spatiotemporal differences of downscale forest carbon sequestration in China over the long term due to data limitations, while also ignoring the large differences in forest carbon sequestration per unit area among different regions. Here, a basic dataset of forest carbon sequestration among counties and grids in China is constructed and the temporal drivers and spatial differences of forest carbon sequestration were investigated from the perspectives of counties' administrative boundaries and 0.5 by 0.5 degree grid combining modelling, GIS spatial analysis and a decomposition method. Changes in forest land use between 2000 and 2020 were also analysed. The results highlight the importance of forests in managing carbon sequestration among all types of terrestrial vegetation and the differences in forest carbon sequestration per unit area. The scale effect increased forest carbon sequestration in the first two periods (2000–2005 and 2005–2010), followed by a decrease since 2010. The intensity effect promoted carbon sequestration; in particular, a dramatic increase was observed from the second (2005–2010) to the third period (2010–2015). The heterogeneity of the scale effect of forest carbon sequestration increased compared to that of the intensity effect, both from administrative and geographical divisions. The scale and intensity effects of counties located in the northern regions of northeast China enhanced forest carbon sequestration, while counties located in southern and central China inhibited it during the study period. The scale effect of grids changed from enhanced to inhibited forest carbon sequestration mainly in northeast China near 120°E, whereas the intensity effect of grids increased from inland regions in central China to eastern coastal regions during the study period. This study provides references for policymakers to set differentiated emission reduction targets considering the local forest carbon sequestration.