Effects of thinning and mixing canopy tree species on species diversity of forest plants in cool temperate Satoyama area

日本的许多森林地区都被废弃的灌木林和人工针叶林所占据。未受林业活动影响的天然林仅限于小面积地区。撂荒灌木林和人工针叶林由于在短时间内反复采伐而中断演替，森林结构相对均一。因此，由不同更新阶段组成的异质镶嵌结构在废弃灌木林和人工针叶林中消失了。本项目研究了不同冠层条件和森林管理对寒温带代表性森林植物物种多样性的影响。该项目的研究是在日本中部新泻县的上川村进行的。第一章对撂荒灌木林区潜在植物物种多样性进行了估算。第二章研究了不同冠层条件对杉木人工林、阔叶针叶混交林和撂荒灌木林地表光环境和物种多样性的影响。揭示了不同林冠条件下各林型植物种类的分布规律。第三章对保护森林植物物种的森林经营制度进行了考察。第四章对人工林隙中阔叶树种的更新情况进行了连续3年的研究。在每个章节中，讨论了恢复中山地区森林植物物种多样性的管理方法。

A lot of forest areas in Japan have been dominated by abandoned coppice and artificial coniferous forests. Natural forests which have not been affected by forestry activity are restricted to small areas. Forest structure in the abandoned coppice forests and artificial coniferous forests is relatively homogeneous due to interruption of succession by repeated cutting in a short period. Therefore heterogeneous mosaic structure which is comprised of various regeneration phases has been disappeared in the abandoned coppice and artificial coniferous forests.This project examined how different canopy conditions and forest management affected specie diversity of forest plants in representative forests of cool temperate zone. The study of this project is conducted in Kamikawa village, Niigata Prefecture, central Japan.In the first chapter, potential plant species diversity was estimated in the abandoned coppice forest areas. In the second chapter, the effect of different canopy condition on light environment of forest floor and plant species diversity was examined in artificial Japanese cedar forests, broadleaf-conifer mixed forests and abandoned coppice forests. The guilds of plant species in each forest type with different canopy conditions were revealed. In the third chapter, forest management system conserving forest plant species was examined. In the forth chapter, regeneration of broad-leaf tree species in artificial canopy gaps was investigated after successive three years after creating the gaps. In each section, management method which restores the species diversity of forest plants in Satoyama area was discussed.