Representative pioneer tree root systems in the subtropical area of South China were examined with regard to their structure, underground stratification and biomass distribution. Excavation of skeleton roots and observation of fine roots of seven species including the Euphorbiaceae, Theaceae, Melastomataceae, Lauraceae and Fagaceae families was carried out. The results showed that: (1) Pioneer tree roots in the first stage of natural succession were of two types, one characterized by taproot system with bulky plagiotropic branches; the other characterized by flat root system with several tabular roots. The late mesophilous tree roots were characterized by one obvious taproot and tactic braches roots up and down. Shrub species roots were characterized by heart fibrous root type featured both by horizontally and transversally growing branches. Root shapes varied in different dominant species at different stages of succession. (2) Roots of the different species varied in the external features—color, periderm and structure of freshly cut slash. (3) In a set of successional stages the biomass of tree roots increased linearly with the age of growth. During monsoon, the total root biomass amounted to 115.70 t/ha in the evergreen broad-leaved forest; 50.61 t/ha in needle and broad-leaved mixed forest dominated by coniferous forest; and 64.20 t/ha in broad-and needle-leaved mixed forest dominated by broad-leaved heliophytes, and are comparable to the underground biomass observed in similar tropical forests. This is the first report about roots characteristics of forest in the lower sub-tropical area of Dinghushan, Guangdong, China.
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机译:研究了华南亚热带地区具有代表性的先锋树根系统的结构,地下分层和生物量分布。进行了骨骼根的开挖和细大根的观察,包括大戟科,茶科,美乐科,月桂科和菊科7种。研究结果表明:(1)自然演替初期的先锋树根有两种类型,一种是主根系统,具有较大的斜生枝;另一个特征是具有多个表根的扁平根系统。晚熟的树根的特征是明显的主根和战术枝根。灌木树种根的特征是心脏纤维的根类型,其特征是水平和横向生长的分支。在演替的不同阶段,不同优势种的根形不同。 (2)不同种类的根的外部特征-新鲜切成斜线的颜色,皮毛和结构各不相同。 (3)在一系列演替阶段,树根的生物量随着年龄的增长而线性增加。在季风期间,常绿阔叶林的根总生物量为115.70吨/公顷。针叶林和针叶阔叶混交林占50.61 t / ha;在以阔叶类植物为主的阔叶和针叶混交林中,其生物量为64.20吨/公顷,与在类似热带森林中观察到的地下生物量相当。这是关于广东鼎湖山下亚热带地区森林根系特征的首次报道。
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