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作 者 ：魏宏图, Gary L. Walker, 贺善安, 杨志斌, 吴霖, 尹洪生

期 刊 ：植物生态学报 1992年 16卷 1期 页码：52-63

关键词：亦松；年龄等级结构；生命表；更新；种群动；

Keywords:Population, Pinus densiflora age class structure, Life table, Regeneration,

摘 要 ：本文以植被样地调查和树木年轮数据为依据，采用空间代替时间的方法定量地论述了宿城自然保护区赤松林群落区系、种群年龄结构及其更新的特点。通过对群落区系和种群动态两个重要方面的分析，力图为探讨其群落稳定性提供证据。本群落区系组成丰富，以北温带成分为主并含有较大比重泛热带成分，特别是与我国华北山东半岛南部成分具有密切联系。在主林层中，林木大小等级和年龄等级分布都遵循倒“丁”形曲线。林下一年生幼苗枯损率，几乎接近100%。林冠下幼树枯死约占一半，而林冠层枯立木占总活立木数的4%。所有这些信息表明：该种群是以幼苗补员与幼树枯损的平衡来维持其特定的持续生存。从郁闭林冠下幼苗、幼树高枯损率证明其更新速度缓慢，但很有可能由林中空地来更替。本文所建立的种群结构动态模型结果表明：宿城亦松种群现阶段是稳定型种群。论其群落性质则应属于具有南北过渡特点的华北型地文(Physiographic)顶极群落。

Abstract:

Su cheng Ecological Reserve is located within the Yuntai Mountains in the coastal region of northeastern Jiangsu Province. Five typical vegetation types, including hardwoods, conifer and bamboo forests have been reported from permanent plots established in this reserve. Pinus densiflora is the dominant species of the conifer forests and reaches its southern-east distribution boundary in China at the Yuntai Mountains, where the vegetation is mainly composed of North-temperate and Pantropic components. A lot of East Shandong species extrend southward to this location. It is reported as being highly susceptible to infestations of the pine wood nematode which is presently causing severe damage in pine forests of China, Japan and other countries.Among canopy trees size class distributions following an inverse J-shaped curve were observed. Nearly 100% mortality of seedlings was observed past the first year following germination. Approximately half the subcanopy and six percent of canopy trees present were dead. Linear regression analysis of the relationship between age and diameter was significant. The model of population age structure shows:

Y = 1. 5829 x 104e-0.0618X

which Y is the number of survivers at time x in stems/0.4ha. X is the age of the population. The use of population age distribution set up the static life table of Pinus densiflora. This information suggests that this population has sustained consistent growth from seedlings recruitment. High mortality of seedlings and young saplings under the closed canopy of this forest indicates that reproduction has been very slow, probably from gap replacement. The present age structure of this stablized population is apparently due to competition within a naturally established forest, in combination with physiographic, edaphic and climatic factors. Absence of nematode infestation is attributed to the high annual precipitation, higher altitude and the relatively low mean annual temperature of the Yuntai Mountains, as well as the disjunct distribution of these populations and relatively different flora components.

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