針広混交林における林木種の萌芽特性と個体群動態

概要

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The present study focused on the mechanisms and the ecological significance of sprouting of Magnolia obovata Thumb, Tilia maximowicziana Shirasawa and Fraxinus lanuginosa Murata, in a mixed forest in Shiretoko National Park, northern Japan. We defined M. obovata and T. maximowicziana as belonging to the upper canopy, and F. lanuginosa to the lower canopy as the upper-canopy and lower-canopy sprout species, respectively. We investigated the size structure and gap dependence of sprout stems for both the upper-canopy sprout and lower-canopy sprout species. The upper-canopy sprout species were well sprouted and the production of sprout stems was dependent on the parent DBH size, irrespective of gap formation. The sprouting of lower-canopy sprout species was not so vigorous, and the production of sprout stems was governed by gap formation improving the light environment at the level of individual tree size. Therefore, it was suggested that sprouting of the upper-canopy sprout species was associated with individual growth dynamics (i.e. parent tree growth), playing an important role in stabilizing the population dynamics. In contrast, it was expected that the stem sprouting of the lower-canopy sprout species was associated with expansion of productive structures, playing an important role in persistence of the population in the lower canopy layer.
日本生態学会の論文
1997-04-25