Fine root biomass and its turn-over rates in forests

研究了长叶昌柏（Chamaecyparis obtusa Endl）细根生物量的年际和季节变化。日本滋贺县平平山的森林。采用土芯取样法估算细根数量。细根分为直径小于1 mm和直径1 ~ 3 mm两种大小的根。根据细根的形态特征对其进行分类。在现代型土壤中，细根主要分布在与上层矿质土（A层）相对应的0 ~ 10 cm土壤表层。在多类型土壤中，细根大部分分布在土壤有机质层（0 ~ 1层）。细根的水平分布与研究场地内树木的位置无关，表明细根的分布相当均匀。因此，土芯取样法适用于本研究场地细根质量的估算。细根（小于1 mm）生物量在研究期间呈现季节和年度变化，变化范围为2.0 ~ 3.0t/ha。1 mm以上细根的生物量为0.83 ~ 1.3 lt/ha。细根总质量估计为2.7 ~ 3.9t/ha。采用平衡法和凋落物袋法估算细根产量为1.32 t/ha。将估算的细根生物量和产量与北美针叶林的其他细根研究进行了比较。

Annual and seasonal changes in fine root biomass were studied over a 3 year period in a 40 year Chamaecyparis obtusa Endl.forest in Mt.Hiei.Shiga Prefecture, Japan. Amounts of fine root were estimated using the soil core sampling methods. Fine roots consisted of two sizes of roots, i.e.less than 1 mm and 1-3 mm in diameter class. The smaller fine roots were categorized by their morphological characters.In the moder type soils, the majority of fine root occurred in the surface layr of O-10 cm soil corresponding to the upper mineral soil layr(A layr). In the mor type soils, the majority of fine roots distributed in the soil organic layr(A0-1ayr).The horizontal distribution of fine roots was independent of the position of trees within the study site, suggested a rather homogeneous distribution of fine roots. Thus, the soil core sampling method were appropriate for the estimation of fine root mass in this study site.Fine root (size of less than 1 mm )biomass showed seasonal and annual variation over the study period and ranged from 2.0-3.0t/ha. Biomass of fine roots of size above 1 mm ranged from 0.83 - l.3lt/ha. Total fine root mass was estimated to be 2.7-3.9t/ha. Fine root production was estimated by the balance methods and litter bag methods, and was l.32 t/ha. The estimated fine root biomass, and production were compared with other fine root studies in the North American coniferous forests.