Analysis of species and genetic diversities' dynamics in natural forest management.

在北海道的大学森林、东京大学农学院的大学森林进行的自然森林可持续管理系统中，广泛的选择砍伐被认为是可持续木材产品的保障。然而，对进行这种管理的天然林物种多样性和遗传多样性变化的研究很少。然后从物种多样性的角度出发，对广泛选择采伐在天然林利用中存在的问题进行了探讨。以冷杉林为例，探讨了选择采伐的遗传效应。我们还揭示了北海道大学森林中萨沙林冷杉森林的实际遗传多样性。本研究得到以下结果：1)天然林的选择采伐使森林结构发生了变化，特别是树木的直径发生了变化。因此，为了维持森林的物种多样性，砍伐阔叶物种似乎是必要的。2)选择切割降低了沙林冷杉自然林分的同质等位基因组合比例，增加了异质等位基因组合比例。然而，等位基因频率在人群中没有显著变化。3)北海道大学林台北山不同海拔分布的冷杉（Abies sachalinensis）居群间存在遗传分化。

It is thought that sustainable wood product is secured by the extensive selection cutting which is a sustainable management system of natural forest conducted in University Forest in Hokkaido, The University Forests, Faculty of Agriculture, The University of Tokyo. However there is little research on the changes in species diversity and genetic diversity of the natural forest where this management was conducted. Then we put the problems in the utilization of natural forest by the extensive selection cutting in order and discussed on them from the viewpoint of species diversity. We discussed on the genetic effect of selection cutting of Abies sachalinensis forest as an practical sample. And we also revealed the actual genetic diversity of Abies sachalinensis forests in the University Forest in Hokkaido.Following results were obtained by this research ; 1) Forest structure, especially in diameter of trees, had been changing by the selection cutting in the natural forest. Then it seemed to be necessary to cut broad-leaved species to maintain the species diversity of the forest. 2) Percentage of homogeneous allele combinations was decreased and heterogeneous allele combinations were increase in the natural stand of Abies sachalinensis by the selection cutting. However there was not significant change in allele frequencies in the population. 3) Genetic differentiation was detected among Abies sachalinensis populations distributed a different altitude on Mt. Tairoku-san in University Forest in Hokkaido.