天然林における林木と樹冠の空間分布

抄録

The distributional pattern of crowns was analyzed by the coverage of crown covers (regarded as an elipse) and their center positions and compared with those of stems (standing positions) in several types of natural mixed forests (6 stands) of Hokkaido. The distributions of the crown-cover centers were uniform or random in upper layer trees, and all random in total trees (DBH&gnE5.0 cm). The crown cover distributions (based on coverage) in a lower layer were found to be more contagious than those in an upper layer, while the distributions of the stems were usually contagious ones. In the measuring of inter-layer distribution overlapping, the crown covers and their centers showed the same exclusive patterns between two of three layers, irrespective of the stem overlapping. These results reveal that trees survive by dividing their crown spaces in a level and escaping from the upper crowns. This simple structure was the main frame of the crowns' spatial distribution through the various types of natural mixed forests, and it had a scarce relationship with their stem distribution. The forming process of these patterns of crown distribution was discussed.