贡嘎山亚高山林地碳的积累与耗散特征

根据贡嘎山海螺沟内5种主要林地上的生物量调查、土壤呼吸和光合作用测定，研究亚高山地区典型林带上C的存贮、吸收和排放关系。对于海拔3000 m附近的峨眉冷杉林，其地上和地下C贮量分别为177.4 t/hm²和143.2 t/hm²，森林光合作用吸收的C量在22～24 t/hm²·a之间，通过呼吸释放C量为3～5.5 t/hm²·a (乔木冠层) 和10～19 t/hm²·a (地面土壤及根系)，年光合作用净固定的C为7.05 t/hm²。低海拔处生态系统C的呼吸量较大，100a以内的中幼龄树木固C能力高于成熟林的固C作用。林地在成为过熟林之前主要还是C的汇，林间裸地是大气的C源。

The Carbon Accumulation and Dissipation Features of Sub-alpine Woodland in Mt. Gongga

Based on the biomass investigation, soil respiration and plant photosynthesis measurement of dominant trees in Hailuogou valley of Mt. Gongga, Southwest China, the carbon(C) storage, absorption and release for several typical woodland in sub-alpine zones have been discussed. For Abies fabri forest of 3000 m above sea level, the C storage amount is 177.4 t/hm 2 for plant above ground surface and 143.2 t/hm 2 for soil. The annual gross C fixed by vegetation photosynthesis is 20-24 t/hm 2 . The C release by canopy respiration is 3.0-5.5 t/hm 2 for arbors and 10-19 t/hm 2 for soil and roots. The total annual net C fixed in forest ecosystems is about 6.0-7.1 t/hm 2 . At lower position, the woodland released C amount is higher than that of woods at higher place. The C fixed capacity of renewed forest with middle-aged trees is higher than that of mature forest.