Soil CON efflux of forest ecosystem in China: distribution and controlling factors
中国森林生态系统土壤CO2释放分布规律及其影响因素

The observed increase in levels of atmospheric CO2 and the signing of the UN Framework Convention on Climate Change have increased interest in the global warming and the global carbon cycle. What the role of terrestrial ecosystems plays in the pattern of the global change is one of studied hotspots. As one of the key components in the global carbon cycle, released CO2 from soil is one of the major pathways to exchange CO2 between soil and atmosphere, which is second only to gross primary productivity. Therefore, the response of soil carbon pool to the global warming is another studied focus issue in the recent years. In this paper, relative information of soil CO2 efflux and climatic, biotic factors of forest ecosystem in China were collated from published studies, then the distribution of soil CO2 efflux of forest ecosystems and its correlations to these factors were identified. Not only the studied forest ecosystems varied in composition and function, but also soil CO2 efflux of these forest ecosystems differed significantly. On national scale, the averaged soil CO2 efflux of forest ecosystems was (1.79±0.86) g C m-2 d-1, and declined gradually from the lower latitude to higher latitude. As a complex ecological process, many biotic and abiotc factors could influence soil CO2 efflux independently or interactively. By the means of distinguishing the responses of soil CO2 efflux to temperature, precipitation, productivity and litterfall, this paper suggested these factors affected soil CO2 efflux positively on national scale. Furthermore, the distribution of soil CO2 efflux on national scale was due to the distribution of climatic and biotic factors just about. The temperature sensitivity of soil CO2 efflux in forest ecosystem in China, Q10 value, was estimated. It was 1.5 and much lower than the global averaged value, 2.0.