闽西北地区不同龄组常绿阔叶混交林生态系统碳储量结构特征

The Structure characteristics of carbon storage of ecosystem of ever-green broad-leaved mixed forest with different forest ages in the north-west of Fujian province

选取福建西北部地区多群落类型组成的常绿阔叶混交林为研究对象，通过典型样地调查法，对生态系统各个层次进行取样调查，采用“相对生长法”计算乔木层生物量，灌木层、草本层和凋落物层采用全部收获法测得其生物量，对土壤层的调查采用剖面法加土钻法，代表性样品碳含量的测定采用重铬酸钾-外加热容量法。在此基础上，分析了该地区不同林龄常绿阔叶林生态系统碳储量及其格局特征，结果表明，（1）闽西北地区常绿阔叶林生态系统平均碳储量为260.63 t·hm-2。在每个发育阶段，各层片对整个生态系统碳储量的贡献率相对稳定，空间分布格局特征相似。幼龄林、中龄林、近熟林、成过熟林生态系统的碳储量分别为192.14、221.15、317.11和312.12 t·hm-2，基本表现出随林龄增加而逐渐增大的趋势。（2）乔木层、灌木层、草本层、凋落物层的平均碳质量分数分别为48.5%、46.9%、41.2%、44.0%，每个层片中，各器官的碳含量差异不大，乔木层、灌木层及草本层的碳质量分数表现出随层片高度降低而减小的趋势。土壤碳质量分数由表层到底层逐渐减小。0～10、10～20 cm土层碳质量分数均显著大于其余三个土层。（3）生物量碳储量在每个层片随着龄组不同，表现出不同的变化趋势。乔木层碳储量大小排序为近熟林﹥成过熟林﹥中龄林﹥幼龄林，灌木层与草本层在不同发育阶段的碳储量，均表现出以下规律：从幼龄林到中龄林不断增长，在中龄林达到最大值后，又随发育的进行显现出不断下降的趋势。随着地表凋落物现存量的不断增加，其碳储量也表现出幼龄林﹥中龄林﹥近熟林﹥成过熟林的趋势。土壤的平均碳储量为134.986 t·hm-2，随着林分发育，表现为成过熟林﹥近熟林﹥中龄林﹥幼龄林。

To evaluate the Carbon Storage of the ever-green broad-leaved forests in Fujian Province, ten 1 000 m2 plots belonging to different successional stages were selected and plant biomass and soil carbon content were measured. The biomass of arborous layer was calculated by using relative growth method, while the biomass of shrub, herb and litter layers were calculated by using the full harvest method. The cross-section method and soil drilling methods were used to determine the soil carbon content. The results indicated that the average carbon storage of the ever-green broad-leaved forest was 260.63 t·hm-2. The total carbon storage were 192.14, 221.15, 317.11 and 312.12 t·hm-2 for young forest, half-mature forest, near-mature forest and over mature forest, respectively, indicating the carbon storage gradually increases with succession. The contribution of the carbon content of different layers to entire ecosystem were relatively stable and did not vary in different successional stages. The means of carbon concentration for different layers did not differ significantly, and were 48.5%, 46.9%, 41.2%and 44.0%for arborous, shrub, herb and litter layers, respectively. The carbon content were decreased from arborous to herb layers. The carbon concentrations for 0-10 cm and 10-20 cm soil layers were significantly greater than deeper soil layers. The carbon storage of different layers varied with successional stages. The carbon storage of arborous layer followed the order： near-mature forest 〉 overmature forest〉half-mature forest〉young forest. The carbon storage of shrub and herb layers increased with development and reached the maximum values in the half-mature stages. After that, the carbon storage of shrub and herb layers gradually decreased. With the increasing of litter content, the total carbon storage increased with the successional stages, young forest〉half-mature forest〉near-mature forest〉overmature forest. The soil average carbon storage is 134.986 t·hm-2. Similarly, carbon storage of soil increased with forest succession, showing that overmature forest〉near-mature forest〉half-mature forest〉young forest.