The Morphological Plasticity of Dwarf Bamboo (Pleioblastus chino) Influences Stemflow Generation Under Different Canopy Conditions

We investigated the morphological traits and stemflow production of the understory dwarf bamboo Pleioblastus chino under different canopy conditions in a temperate deciduous forest. The mean stem density was 1.9 times higher in the open (Op) plot, in which the canopy had been removed, than in the forested (Uc) plot. Due to the high availability of solar radiation in the Op plot, leaves were concentrated in the upper sections of stems, and the leaf area index was 2–3 times greater than that in the Uc plot. Despite differences in leaf morphological traits, stemflow corresponded to precipitation inputs in both plots. However, the stemflow rate responded more rapidly to precipitation in the Op plot than the Uc plot; this was related to differences in the amount and timing of initial canopy storage and interception loss. The mean stemflow volume was 1.8–2.4 times greater in the Op plot than the Uc plot due to differences in interception loss. The morphological adaptations under the high-irradiance conditions of the Op plot altered the leaf height and distribution, enabling individual stems with a greater number of leaves attached at higher positions on the stem to collect rainwater more efficiently and generate greater stemflow. Classification based on stem height and leaf number ratio also highlights adaptive morphologies in response to light conditions, which enhance rainwater collection and stemflow efficiency in the Op plot. Thus, alterations in the morphological traits of P. chino enhanced not only the radiation use efficiency but also the water use efficiency via water transfer to the rhizome. These results suggest that morphological plasticity associated with forest canopy conditions enhances the ecological adaptivity of dwarf bamboo through radiation and water use.