Acidic deposition, which is mainly caused by atmospheric pollution, is one of the global environmental problems. Thinning is an effective management to improve the tree productivity, reduce the wildfire risk and maintain a healthy forest. Since thinning may reduce the effect of acidic deposition, the effect of thinning on acidic deposition was estimated. The biomass, soil properties, pH value of runoff and groundwater in both unthinned and thinned Chinese fir plantations were measured and compared over a 5-year period (2-6 years after thinning)...