Ecosystem Carbon Allocation of a Temperate Mixed Forest and a Subtropical Evergreen Forest in China

温带阔叶红松林和南亚热带常绿林生态系统碳分配的比较研究（英文）

Ecosystem carbon allocation can indicate ecosystem carbon cycling visually through its quantification within different carbon pools and carbon exchange.Using the ecological inventory and eddy covariance measurement applied to both a mature temperate mixed forest in Changbai Mountain (CBM)and a mature subtropical evergreen forest in Dinghu Mountain (DHM),we partitioned the ecosystem carbon pool and carbon exchange into different components,determined the allocation and analyzed relationships within those components.Generally, the total carbon stock of CBM was slightly higher than that of DHM due to a higher carbon stock in the arbor layer at CBM.It was interesting that the proportions of carbon stock in vegetation,soil and litter were similar for the two mature forests.The ratio of vegetation carbon pool to soil carbon stock was 1.5 at CBM and 1.3 at DHM.However, more carbon was allocated to the trunk and root from the vegetation carbon pool at CBM,while more carbon was allocated to foliage and branches at DHM.Moreover,77% of soil carbon storage was limited to the surface soil layer (0-20cm),while there was still plentiful carbon stored in the deeper soil layers at DHM.The root/shoot ratios were 0.30 and 0.25 for CBM and DHM,respectively.The rates of net ecosystem productivity (NPP)to gross ecosystem productivity (GPP)were 0.76 and 0.58,and the ratios of ecosystem respiration (Re)to GPP were 0.98and 0.87for CBM and DHM,respectively.The net ecosystem carbon exchange/productivity (NEP)was 0.24t C ha^-1 yr^-1 for CBM and 3.38t C ha^-1 yr^-1 for DHM.Due to the common seasonal and inter-annual variations of ecosystem carbon exchange resulting from the influence of environmental factors,it was necessary to use the long record dataset to evaluate the ecosystem sink capacity.

生态系统碳分配通过量化不同碳库及其交换量从而直观反映碳循环过程。基于中国生态系统研究网络(CERN)长白山温带阔叶红松林(CBM)和鼎湖山南亚热带常绿林(DHM)2010年群落调查资料,计算得到两个生态系统的植被、凋落物和土壤的碳储量及其各部分,并结合生态系统通量观测以及呼吸不同组分的估算,初步构建了两类成熟林生态系统的碳分配模式。结果表明,CBM的碳储量略高于DHM,其差异主要来自于乔木的碳储量,并且两类森林植被、土壤和枯落物碳储量的分配比例呈现相似的特征。在植被碳库中,CBM将较多的碳分配到乔木中的树干和根系,而DHM则更多将碳分配到乔木中的枝条和叶片。CBM和DHM植被碳库与土壤碳库的比例分别为1.5和1.3,根冠比分别为0.30和0.25。CBM土壤碳储量的77%分布于表层,而DHM深层土壤仍有较多的碳储存。CBM和DHM的NPP/GPP分别为0.76和0.58,Re/GPP则分别达到了0.98和0.87,而自养呼吸与异养呼吸的比例分别为0.41和1.23。其差异的主要原因是DHM叶片、枝条和根系的自养呼吸量较高导致。观测结果显示,2010年CBM为弱的碳汇(0.24),而DHM表现为较强的碳吸收能力(3.38),但由于碳交换往往在环境因子影响下出现较大的季节和年际变化特征,因此还需要更长时间观测数据以更为准确地评价生态系统的碳汇能力。