シオジとサワグルミ稚樹の伸長特性

抄録

Patterns of leaf expansion and shoot elongation of Fraxinus platypoda and Pterocarya rhoifolia saplings were studied in a riparian forest dominated by F. platypoda and P. rhoifolia along the Nakatsugawa Branch of the Arakawa River in the Chichibu mountains of central Japan. The saplings of F. platypoda were found not only in canopy gaps but also under the canopy, whereas P. rhoifolia was found only in canopy gaps. The patterns of leaf expansion and shoot elongation differed between the two species. F. platypoda showed leaf emergence and leaf fall of short duration, whereas those of P. rhoifolia were of longer duration. The growth amounts of current shoots of P. rhoifolia were greater than those of F. platypoda, and the number of leaves on current shoots of the former was higher than that of the latter. This study indicates the importance of patterns of leaf expansion and shoot elongation of saplings in relation to recovery of a gap in the canopy.