森林是CO2、CH4和N2 O等温室气体重要的源、汇和转换器,在全球气候变化过程中起着重要作用。森林温室气体通量常常受到人类经营活动的影响。经营活动对森林温室气体排放影响的研究对于控制温室气体通量，调控经营措施，减缓温室效应意义重大。本项目选择杉木成熟林为研究对象，拟通过研究皆伐+天然更新、皆伐+带状人工更新、皆伐+穴状人工更新和不采伐四种经营方式下的土壤CO2、CH4 和N2O 三种温室气体排放的月变化、季节变化和年际变化；阐明皆伐后不同更新方式下土壤温室气体通量的变化特征及趋势，分析其与林地光照、温度、湿度等生态环境因子、土壤有机碳、硝态氮等理化性质和土壤微生物的相关关系，构建土壤温室气体排放与各环境因子的关系模型，揭示皆伐后不同更新方式作用于温室气体通量的可能机制。为科学认识采伐更新对林地土壤温室气体排放的影响机制提供理论依据，为提出改善经营措施从而减缓温室气体排放提供理论基础。

Forest ecosystems are significant carbon and nitrogen sinks at the global scale, and play an important role sequestering greenhouse gases and regulating climate. The three greenhouse gases (CO2,CH4,N2 O) fluxes from forest are often influenced by human management activities. It is important to carry out the study of the effect on greenhouse gases by forest management activities for controlling soil greenhouse gas fluxes, adjusting management measures and mitigating greenhouse effect. We will examine the effects of four kinds of management scenarios on the fluxes of soil CO2, CH4, and N2O in a mature Cunninghamia lanceolata stand, such as clearfelling + natural regeneration, clearfelling + strip site preparation and artificial regeneration, clearfelling + soil preparation in small hole artificial regeneration, and control (no cut). Soil CO2, CH4, and N2O as well as environmental factors such as light, temperature, humidity, soil physical and chemical properties and soil microorganism would also be examined for 3 growing seasons. We will clarify the characteristics and trends of different regeneration after clearfelling on soil greenhouse gas fluxes, analysis the relationship between it and the organic carbon content of the soil, soil microorganisms, soil total nitrogen, nitrate, ammonia nitrogen content, pH value, soil temperature, humidity and other factors, reveal the impact mechanism and build the relational model of soil greenhouse gases flux and environmental factors. It will provide a scientific basis for evaluating felling and regeneration measures on the trend of soil greenhouse gases fluxes, and management measures for controlling ecosystem greenhouse gases fluxes.