Spatial distribution patterns of Sasa palmata in relation to light conditions across gap-understory continuum in a beech (Fagus crenata) forest

To evaluate how changes in spatial distribution patterns of S. palmata depend on changes in those of relative PPFD, we investigated the relationships between spatial distribution patterns of S. palmata and those of relative PPFD across gap-understory continuum in a natural beech forest. Both relative PPFD and coverage of S. palmata were maximum at the gaps and decreased with increasing the distance from gap edge to understory. The rate of decrease in relative PPFD was significantly greater than that in Sasa coverage. Although PPFD was lower than light compensation point of S. palmata in more than 70% of the observed area of understory, substantial amount of S. palmata persisted in the understory area. These traits suggest that photosynthate produced by the leaves of Sasa in the gaps would be transported to the shaded shoots in the understory through connected rhizomes. The physiological integration would enhance the persistence of S. palmata in the forest understory.