著者

湯川 淳一 山内 政栄 永井 定明 徳久 英二

出版者

日本生態学会

雑誌

日本生態学会誌 (ISSN:00215007)

巻号頁・発行日

vol.27, no.3, pp.171-175, 1977-09-30

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YUKAWA, Junichi, YAMAUCHI, Seiei, NAGAI, Sadaaki & TOKUHISA, Eiji (Entom. Lab., Fac. Agric., Kagoshima Univ., Kagoshima). 1977. Leaf longevity and the defoliating process in saplings of Actinodaphne longifolia (BLUME) NAKAI. Jap.J.Ecol., 27 : 171-175. This investigation was made as a part of the authors' ecological studies of broad-leaved evergreen trees and associated gall midge populations which have been continued since 1970 in a natural forest of Mt. Shiroyama, situated in the centre of Kagoshima-city. The mean leaf longevity in saplings of Actinodaphne longifolia (BLUME) NAKAI was estimated at 51.58 months by counting both the numbers of surviving leaves and scars of leaves that had been shed. The mean numbers of new leaves per twig fluctuated annualy between 5.13 and 10.60,but the fluctuations were not great in the taller trees or in the younger generations of the shorter trees. The defoliating process from the time of leaf emergence to the end of April in 1976 was indicated by τ-index to be nearly random in almost every year. The simple and easy method adopted in this study may be applicable in some cases for estimating the leaf longevity and the defoliating process of other broad-leaved evergreen trees.