Abstract
Deciduous broad-leaved trees show a remarkable specific difference in the leaf-flush period in spring. Even under the closed canopy, the light condition of forest floor becomes heterogeneous by place, because of the leaf phenological traits of upper trees. In order to study the influence of this seasonal light regime on the growth of understory plants, the transplanting experiment of Impatiens textori, an annual herbaceous species, was conducted in a ca. 100-year-old forest. Five plots were established under the canopies of early-, intermediate-, and late-flushing trees, and the elongation pattern of main stems of transplanted individuals was monitored. It is elucidated that the growth increments of them were large in the place under influence of the late-flushing-tree canopy, that supplied large amount of photosynthetic photon flux density to the forest floor for a long period in spring.
