Structure and dynamics of riparian forests in the warm-temperate region

1.屋古岛低地河岸林的河岸组成通过与坡面森林区系的比较，根据河流的特征：1)地表过程类型（冲刷与沉积），2)集水区的空间尺度对河岸林的组成进行了分类。干扰频率高的低地河岸林主要成分是寒温带森林中常见的落叶乔木2。研究了暖温带1级河谷地区冲刷区河岸林的结构变化及其扰动机制。地形对次生林的物种组成、乔木分布和演替有重要影响，主要表现在光照和土壤湿度、干扰类型和频率等方面。研究了九州南部暖温带地区冲积扇上天然林的结构，并与斜坡上的森林结构进行了比较。坡地林分主要为总状菊。另一方面，在大型岩石沉积层上以棕榈槭和山茱萸为伴的冲积扇中，以橡胶树为主，在基质沉积层上以榆木和松木为伴的冲积扇中以橡胶树为主。森林结构的变化受到各种干扰的影响，提供了不同的更新生境。

1.Riparian component of the lowland riparian forests in Yakushima IslandThrough comparisons with the flora of slope forests, components of riparian forests were categorized according to the features of river : 1)type of earth surface process (scouring vs. sedimentation), 2)spatial scale of catchment area. Main components of lowland riparian forests with high frequency of disturbance were deciduous trees which are common in cool-temperate forests2.Structure and dynamics of riparian forest in scouring areaStructure variations and disturbance regimes were investigated in an 1-order valley in the warmtemperate region. Topography severely affected to the species composition, tree size distribution and succession of secondary forests through the variaion in 1)light and soil moisture regimes, and in 2)the type and frequency of distrurbance.3.Structure and dynamics of riparian forest in sedimentation areaStructure of a natural forest on an alluvial fan in the warm-temperate region in southern Kyushu was investigated and compared with the forest structure on a slope. The slope stand was occupied by Distylium racemosum. On the other hand, Quercus gilva dominated in the alluvial fan associated by Acer palmatum and Cornus controversa on sediments of large rocks and by Ulmus Davidiana and Sapindus Mukoross on sediments of matrix. These variation of forest structure was affected by various types of disturbance providing different kind of regeneration habitats.