其他摘要：The dense cover of sasa (dwarf bamboo) often inhibits tree regeneration, and silvicultural operations to control sasa are essential so as to ensure natural regeneration of forests. Operations to control sasa are usually conducted following timber harvesting. Controlling sasa under the closed canopy before timber harvesting is expected to ensure the establishment of advanced seedlings and make tree regeneration more successful. However, the effects of operations to control sasa under the forest canopy before timber harvesting have not been previously examined in Japan. In this study, we conducted a field manipulation in stands hinoki (Chamaecyparis obtusa) natural stand, Kiso region, central Japan, to examine the sustainable suppressing effects of the dwarf bamboo, Sasa palmata, under the closed canopy. We conducted five treatments that combined weeding and herbicide application. Every year from 2013 to 2017, in a 1 m2 quadrat per treatment, we collected the aboveground and belowground parts of sasa and measured their biomass, number of culms, and carbohydrate concentration belowground. Sasa lost its culm emergence ability immediately after the first weeding practice in the three treatments that included weeding, and in the next few years, its belowground biomass disappeared. In contrast, the herbicide treatment slightly decreased the aboveground biomass of sasa, but caused no effects in the belowground biomass, indicating that this treatment does not eliminate sasa. Weeding under the closed canopy was the most suitable method to control sasa, raising the natural regeneration potential of hinoki from advanced regeneration.
