Responding to climate change: assessing the current situation and influencing factors of forest carbon sinks in China

In response to global climate change and China's "dual carbon" goals, forest carbon sinks, as a key nature-based solution, have gained importance in balancing human-induced carbon emissions and ecological restoration. This study examines the effectiveness of forest carbon sinks across 31 Chinese provinces from 2003 to 2018, using the forest stock expansion method to quantify the validity of carbon sinks. We explore the spatiotemporal evolution and regional disparities of forest carbon sink validity and identify the influence of research and development intensity, industrial structure upgrading, urbanisation level, government intervention degree, and economic development level factors. A spatial Durbin model is employed to assess both direct and indirect effects of natural and policy factors on the carbon sink's effectiveness in both local and neighbouring provinces. Our findings reveal that forest carbon sink effectiveness follows a pattern of "higher in the west, faster in the east, and catching up in the central region". The results indicate that increased research and development investment and optimised industrial structure positively influence carbon sink growth, whereas excessive government intervention hampers development. Urbanisation and economic development were found to have no significant direct effect. The spatial analysis shows that research and development intensity and industrial optimisation yield positive spillover effects on neighbouring provinces' carbon sink growth, whereas government intervention and urbanisation yield negative, non-significant spillover effects. These findings suggest the need for strengthened regional innovation policies, improved forestry governance, and optimised forestry services to support the high-quality development of the forestry sector.