兴安落叶松林火干扰后土壤有机碳含量变化  

The variability of soil organic carbon content in Larix gmelinii forests after fire disturbances

作　　者：韩春兰[1] 邵帅[1] 王秋兵[1] 李甄[1] 孙仲秀[1] 毛伟伟[1] 

机构地区：[1]沈阳农业大学土地与环境学院,沈阳110866

出　　处：《生态学报》2015年第9期3023-3033,共11页Acta Ecologica Sinica

基　　金：国家973项目(2011CB403206)

摘　　要：在大兴安岭兴安落叶松林区,选择不同恢复年限各种火烧强度(重度、中度、轻度)的火烧迹地进行调查并采集土壤样品,对火后有机层和矿质层有机碳含量变化进行研究,以期为进一步开展森林火灾对区域碳平衡影响的定量评估提供科学依据。研究结果表明:火干扰对土壤有机碳含量变化的影响包括火烧即时影响和火后生境条件变化带来的间接影响。火干扰样地有机层的积累与转化主要是通过火后林冠郁闭度的变化影响的,其有机碳总储量低于对照样地。对于矿质层土壤,重度和中度火干扰后,如果样地发生植被序列演替,即阔叶林植被入侵,样地郁闭度增加迅速,凋落物积累量增大,土壤有机碳含量将随着过火年限的增加而增加;如果样地发生自我更新,样地郁闭度增加缓慢,凋落物分解量大于积累量,土壤有机碳含量将会在一定时间内随着过火年限的增加而减少;但是,无论样地发生植被序列演替还是自我更新,土壤有机碳含量短时间内均无法恢复到火前水平。轻度火干扰后,土壤有机碳含量短期内先增加,随着植被更新情况的发展最终趋于平衡。Fire is the primary disturbance agent in boreal forests,and exerts a major influence on the carbon cycle in this ecosystem. Fire disturbances not only alter the composition of species in the local forest ecosystem and the structure,functions and development of forests across landscapes,but also result in remarkable variations of soil physical and chemical properties,the relative content of nutrient elements and the storage of soil organic carbon. Using remotely sensed data from a Larix gmelinii forest before and after fire in the Great Xing＇ an Mountains,we calculated the Composite burn index（ CBI）,combined with interviews with local guides and field investigations to estimate the intensity and disturbance range of the fire. Soil surveys,sample collections and analyses of different areas of restoration after fire disturbances of different intensities（ high,intermediate and low intensity） were performed. We researched the soil organic carbon variables in detail and discussed the impact of organic and mineral horizons of different fire intensities on soil organic carbon,in order to provide a scientific basis for the quantitative evaluation of the regional carbon balance after forest fires. The results showed that the effects of fire on soil organic carbon included the immediate effects of fire and the indirect effects of changes in habitat conditions after fire. The organic layer was partially or completely burned off during fire disturbances. Moreover,fire changed the morphological characteristics of mineral horizons,increased bulk density and reduced the organic carbon content. The accumulation and transformation of organic carbon was mainly influenced through the consequent changes in plant species,canopy density and recovery times after fire. The total organic carbon content of the organic layer of the fire disturbance sample plot was lower than that of the control. The organic horizons were markedly altered by fire. The organiccarbon content in the organic horizons varied along with the extended reco

关 键 词：土壤有机碳 火干扰 群落演替 兴安落叶松 大兴安岭 

分 类 号：S714.2[农业科学—林学]