A preliminary investigation of surface runoff and soil properties in a moso-bamboo (Phyllostachys pubescens) forest in western Japan

To clarify plot-scale runoff characteristics in bamboo forests, soil properties and surface runoff were measured in a preliminary study of a forested hillslope of moso-bamboo (Phyllostachys pubescens). Infiltration capacities and saturated hydraulic conductivities at 10, 30 and 50 cm depths were similar to or greater in the moso-bamboo forest than in an adjacent broad-leaved forest. This suggests that surface runoff rarely occurs in the moso-bamboo forest. However, surface runoff was observed in seven of 14 storm events. The surface runoff responses to rainfalls were relatively rapid and the amount of surface runoff per storm event depended largely on rainfall. The proportion of the total amount of surface runoff to the total rainfall during the observation period ranged from 19 to 33%, depending on the observation system. This indicates that the greater portion of rainfall infiltrated into the soil. A high density of roots in the surface soil suggests that part of the rainfall was impeded and passed laterally through the surface soil as preferential flow around the root mats and/or the rhizomes, thereby contributing to surface runoff.