Effects Of Future Climate Change On The Storage Of Soil Organic Carbon In Northeast Forest Of China

Forest soil carbon pool is an important component of the terrestrial ecosystems'carbon cycle. The changes of its accumulation and decomposition have direct effects on the terrestrial ecosystem carbon storage and the global carbon balance. Climate change may affect the accumulation and decomposition of forest soil organic carbon(SOC), influence the forest carbon sink, change the carbon exchange fluxes between terrestrial ecosystem and the atmosphere, which further exacerbate or mitigate the trend of global climate change. Therefore, the study of the response of forest SOC to climate change contributes to the understanding the soil carbon processes, to the forest management and the exploration for the possible measurements for the mitigating the climate change. In this paper, based on the CENTURY model developed by Colorado University and the simulation outputs of A2 and B2 climate scenarios by PRECIS, we simulate the changes of SOC storage in the soil surface (0~20 cm)(short for soil organic carbon storage, the same below)of the Northeast Forest Region in China from 2011~2100. The results show as follows:1. Under both A2 and B2 scenarios, the mean annual temperature(MAT) in Northeast China will increase; the annual precipitation has a increasing trend overall.2. Under the doubled CO2, the NPP of forest vegetation in Northeast forest will have an increasing trend;Under both A2 and B2 scenarios, the NPP of forest vegetation will increase in 2030s,2060s and 2090s, the maximum increments will be all in the north of Daxinanling Mountain; Under the temperature rising alone in A2 and B2 scenarios, the maximum increments of the NPP of forest vegetation are in the north of Daxinanling,the south of Xiaoxinganling and the east of Jilin. The change rate of NPP of forest vegetation will increase significantly over time in the eastern of Jilin and Liaoning; Under the rainfall change alone in A2 and B2 scenarios, the NPP of forest vegetation in Northeast forest will decrease.3. Under the doubled CO2, the SOC storage in the Northeast forest has an increasing trend;the SOC pool is still a carbon sink; Under both A2 and B2 scenarios, the SOC storage will increase in the northern part of the Northeast Forest Region and decrease in the east area. The SOC storage in the region will increase in 2030s,2060s and 2090s, the soil carbon sink will become intensified.4. Under the temperature rising alone in A2 and B2 scenarios, the SOC in the east area of the region will decreases significantly and the forest soil carbon pool changes from carbon sink to carbon source. This is because the temperature rising promotes the decomposition of SOC, speeding up the release of soil carbon to atmosphere; Under the rainfall change alone in A2 and B2 scenarios, the SOC storage will increase, especially in the northern and eastern parts of the Northeast Forest region, the soil carbon sink will become intensified. Precipitation change alone may limit the microbial decomposition, reduces the losses of SOC, so the SOC storage increases. It also shows that the precipitation factor plays a very important role in the effect of climate change on SOC storage.