Studies on theAbies population of Mt. Shimagare
Studies on theAbies population of Mt. Shimagare
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岛岳山冷杉种群的研究
DOI：
10.1007/bf02490203
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
N. Fujita
中科院分区：
文献类型：
--
作者：
T. Kohyama;N. Fujita
生存曲线是对日本中部八岳山脉北部志马雷山亚高山波浪再生森林中的冷杉种群进行估计的。几乎同龄林分的反复腐烂和再生是该森林在稳定状态下的本质，因此存活曲线表示为密度随林龄的减少。曲线上有四个不同的阶段。前 10 年（第一阶段）死亡率很高。尽管从茂密树冠下的地面到森林边缘都能观察到发芽现象，但只有一部分幼苗能够存活并形成几乎同龄的年轻再生体。已建立的再生在达到全密度状态之前（第二阶段，直到 32 岁）死亡率较低。当达到完全密度时，如−3/2幂律所示，死亡率由于强烈的自我稀疏而再次增加（第三阶段）。然而，死亡率随着年龄的增长而下降。人们认为这种下降的发生是因为冠层树木的大小和空间分布变得均匀。在最后一个阶段，树木发生集体死亡（第四阶段，约 90 年）。据信，树木之间的均匀性会导致林分倒塌。
The survivorship curve is estimated for theAbiespopulation of the subalpine wave-regenerated forest on Mt. Shimagare in the northern Yatsugatake Mountains, Central Japan. The repetition of decay and regeneration of nearly even-aged stands is the nature of this forest in a steady-state, so that the survivorship curve is given as the decrease of density with stand age. Four distinct stages are recognized on the curve. The mortality is high in the first 10 years (stage i). Though germination is observed from the floor under dense canopy to the forest edge, only a portion of the seedlings can survive and form a nearly even-aged young regeneration. The established regeneration enjoys a low mortality before it attains a full density state (stage ii, until 32 years). When full density is reached, as indicated by the −3/2 power law, the mortality increases again due to an intensive self-thinning (stage iii). However, mortality rate declines with age. This decline is thought to occur because canopy trees become uniform in size and spatial distribution. In the last stage the aggregative dying-off of trees takes place (stage iv, about 90 years). The uniformity among trees is believed to promote the collapse of the stand.