高尾山における先駆性高木種5種の地形分布と樹形の意義

抄録

Patterns of topographical distribution of five pioneer tree species (Idesia polycarpa, Cornus controversa, Zanthoxylum ailanthoides, Euptelea polyandra, Mallotus japonicus) and their tree forms were studied in natural forests on Mt. Takao, Tokyo Metropolitan county, central Japan. The study area was divided into six landform types, four of which were free from human activities (upper side slopes, dells, lower side slopes and foot slopes). Patterns of topographical distribution of each species were explainable by their tree form properties (trunk angle, trunk number and maximum tree height). Such a relationship between the form properties and distribution of trees was due to differences in the disturbance regime (mainly by landslides) of each landform type. Species with higher ability to grow when the trunk is inclined and to develop sprouts were more tolerant of higher disturbance pressure. When taller stands suffered lower disturbance pressure, species with a larger maximum tree height and higher ability to grow below the canopy were at an advantage.