Response of vegetation and soil carbon accumulation rate for China’s mature forest on climate change

Aims
This study aims to evaluate the impacts of future climate change on vegetation and soil carbon accumulation rate in China’s forests.
Methods
The vegetation and soil carbon storage were predicted by the atmosphere-vegetation interaction model (AVIM2) based on B2 climate change scenario during the period of 1981-2040. This study focused on mature forests in China and the forested area maintained constant over the study period. The carbon accumulation rate in year t is defined as the carbon storage of year t minus that of year t-1.
Important findings
Under B2 climate change scenario, mean air temperature in China’s forested area was projected to rise from 7.8 °C in 1981 to 9.0 °C in 2040. The total vegetation carbon storage was then estimated to increase from 8.56 Pg C in 1981 to 9.79 Pg C in 2040, meanwhile total vegetation carbon accumulation rate was estimated to fluctuate between -0.054-0.076 Pg C·a^-1, with the average of 0.022 Pg C·a^-1. The total soil carbon storage was estimated to increase from 30.2 Pg C in 1981 to 30.72 Pg C in 2040, and total soil carbon accumulation rate was estimated to vary in the range of -0.035-0.072 Pg C·a^-1, with the mean of 0.010 Pg C·a^-1. The response of vegetation and soil carbon accumulation rate to climate change had significant spatial difference in China although the two time series did not show significant trend over the study period. Our results also showed warming was not in favor of forest carbon accumulation, so in the northeastern and southeastern forested area, especially in the Changbai Mountain, with highest temperature increase in the future, the vegetation and soil carbon accumulation rate were estimated to decrease greatly. However, in the southern of southwestern forested area and other forested area, with relatively less temperature increase, the vegetation and soil carbon accumulation rate was estimated to increase in the future.