基于当前仍不明确冬季积雪量降低及伴随的冻融变化如何影响中高纬度温带森林土壤碳素动态及其稳定性，本项目拟通过我国东北温带森林冬季积雪控制实验观测，结合野外13C标记物实验观测、荧光光谱分析和土壤呼吸组分δ13C值测定，研究冬季积雪对非生长季和生长季温带森林土壤总呼吸、自养和异养呼吸以及各自温度敏感性和土壤有机碳分解激发效应的影响，分析冬季积雪对温带森林土壤溶解性有机碳淋溶及其稳定性的影响。整合实验样地有机层和矿质层土壤碳含量及化学结构、细根生物量、微生物量、溶解性有机碳含量及其有效性、团聚体碳含量及其可矿化性、碳循环相关微生物群落和活性以及气象要素变化，力求阐述冬季积雪对我国东北温带森林土壤碳素排放和稳定性的影响机制。研究结果为人们有效认识冬季积雪降低及伴随的冻融变化下温带森林土壤碳循环过程及其驱动机制提供基础理论和方法体系，利于推动人们开展我国高寒区森林土壤碳循环对冬季气候变化的响应研究。

There is limited knowledge about the responses of soil carbon dynamic and its stabilization of temperate forests in mid-high latitude zones to a decrease in winter snow and its following freeze-thaw changes. In this program, temperate forest stands at different succession stages, which locate at the foot of Changbai Mountains in northeastern China, can be selected to mainly study the responses of the forest soil carbon dynamic and its stabilization to the removal of winter snow and their influencing factors. Long-term measurements of field experiments with and without the removal of aboveground winter snow under selected temperate forest stands will be carried out, to study the dynamic changes in soil respiration, autotrophic and heterotrophic respiration and their temperature sensitivity as well as leaching fluxes of dissolved organic carbon and nitrogen during non-growth and growth seasons each year. In combination with field measurements of the δ13C values derived from soil respiration components, field experiment using labeled 13carbon source, a parallel factor analysis to decompose florescence excitation-emission matrices and soil biological technologies, we try to systematically study the changes in priming mineralization of forest soil native organic carbon under selected forest stands and the responses of the priming mineralization to the removal of winter snow and the main driving mechanisms. Together with the changes in forest aboveground litter C and mineral soil C contents and their chemical components, biomass of fine roots and microbial biomass, amount and bioavailability of dissolved organic carbon, the potential mineralization of organic carbon in soil aggregates, and the soil carbon cycle-associated microbial population and activities, the mechanisms involving the fluxes and stabilization of carbon in temperate forest soils will be eventually analyzed. The results can provide basic theories and methods for future researches in the field of soil carbon cycle in cold temperate forest stands of China and its responses to winter climate changes such as decreasing winter snow and its following freeze-thaw changes.