To investigate the impacts of the invasion by bamboo on fluxes of nutrients and pollutants, the nutrient/pollutant fluxes and canopy interactions, including neutralization of acidity, leaching and uptake of nitrogen (N), were characterized in conjunction with rainfall partitioning in a Moso-bamboo (Phyllostachys pubescens) forest. Measurements of precipitation volume, pH, major ions, and silicate (SiO2) in rainfall, throughfall and stemflow were collected weekly in a Moso-bamboo forest located in Munakata City, Western Japan for 1 year. Results showed that rainfall partitioning into stemflow was larger than that for other types of forest, which may be due to the properties of Moso-bamboo forest structure, such as a straight and smooth culm. Inorganic N (NO3− + NH4+) and S (SO42−) fluxes of throughfall and stemflow were approximately 1·6 and 1·3 times higher than that of rainfall, respectively. Contribution of stemflow flux to inorganic N and S fluxes to the forest floor was high. This could be due to lower uptake of inorganic N through culm and a higher rainfall partitioning into stemflow than that for other types of forest. The Moso-bamboo canopy neutralized rainfall acidity, reducing the fluxes of potentially acidifying compounds via throughfall and stemflow. Canopy leaching of K+ was distinctly higher than that of Mg2+ and Ca2+ and could be related to the high mobility of K+ in plant tissues. Cl− and SiO2 were readily leached as for K+. The impact of the invasion by bamboo on nutrient cycling was discussed. Copyright © 2010 John Wiley & Sons, Ltd.