广西不同林龄马尾松人工林生态系统碳储量及其分配格局

Carbon Storage and Distribution Pattern of Pinus massoniana Plantations Ecosystem in Different Forest Ages in Guangxi

关键词:  马尾松人工林  生态系统  碳储量  分配格局  林龄

Key words:  Pinus massoniana plantations  ecosystem  carbon storage  distribution pattern  forest age

摘要:

为阐明马尾松(Pinus massoniana)不同林龄生态系统碳汇机制以及固碳能力的差异，本研究基于样地调查，选用空间代替时间的方法，选取立地条件大致相似、不同林龄(6、19、32、58 a)的马尾松人工林生态系统为研究对象，依据收获法和建立各器官生物量模型的方法估测生物量，采集0-60 cm土层土壤样品，测定生态系统各层次的有机碳含量，以此估算生态系统的碳储量。结果表明：不同林龄马尾松人工林林下灌木层、凋落物层和根系有机碳含量均呈增加趋势，而草本层则相反，各层次有机碳含量整体表现为凋落物层＞灌木层＞草本层＞根系；其生态系统碳储量总体表现为增加趋势，过熟林显著提高了144.14%，其中，乔木层、凋落物层、根系和土壤层碳储量的变化规律与生态系统一致，而灌木层和草本层则相反；植被层碳储量贡献率提高，而土壤层碳储量贡献率下降，凋落物层无明显变化；年净固碳量以幼龄林和中龄林较高，表明马尾松人工林固碳能力较强，具有相对较高的生物生产力水平。近自然恢复可进一步提升不同林龄马尾松人工林的碳固持能力，提高植被层生物量和土壤碳含量、增强土壤固碳能力、优化森林结构、维持较高生产力和降低人为干扰等是提高马尾松人工林生态系统碳汇功能的重要举措。

Abstract:

In order to clarify the differences in carbon sink mechanism and carbon sequestration capacity of different forest ages of Pinus massoniana, based on the sample plot survey,this study selected the method of space instead of time,and selected the P.massoniana plantation ecosystem with roughly similar site conditions and different forest ages (6,19,32,58 a) as the research object.The biomass was estimated according to the harvest method and the method of establishing the biomass model of each organ.The soil samples of 0-60 cm soil layer were collected to determine the organic carbon content of each layer of the ecosystem,so as to estimate the carbon storage of the ecosystem.The results showed that the contents of organic carbon in the shrub layer,litter layer and root system of P.massoniana plantations at different stand ages showed an increasing trend,while the herb layer showed the opposite trend.The overall organic carbon content of each layer showed litter layer>shrub layer>herb layer>root system.The carbon storage of the ecosystem showed an increasing trend,and the over-mature forest increased significantly by 144.14%.Among them,the variation of carbon storage in tree layer,litter layer,root system and soil layer was consistent with that of ecosystem,while that in shrub layer and herb layer was opposite.The contribution rate of carbon storage in vegetation layer increased,while the contribution rate of carbon storage in soil layer decreased,and there was no significant change in litter layer.The annual net carbon sequestration of young and middle-aged forests was higher than that of young and middle-aged forests,indicating that the carbon sequestration capacity of P.massoniana plantation was strong and had a relatively high biological productivity level.Close-to-nature restoration can further enhance the carbon sequestration capacity of P.massoniana plantations of different forest ages.Improving vegetation layer biomass and soil carbon content,enhancing soil carbon sequestration capacity,optimizing forest structure,maintaining high productivity and reducing human disturbance are important measures to improve the carbon sink function of P.massoniana plantation ecosystem.