This study was carried out to examine the effects of soil acidification on growth and nutrient status of 2-year-old Pious densiflora Sieb. et Zucc. seedlings grown for 120 days in brown forest soils acidified with H₂SO₄ solution with or without leaching rations from the soil. The concentrations of A1 in the acidified soils increased with increasing amount of H^+ added to the soil, The total dry weight of the seedlings was decreased by the addition of the H₂SO₄ solution. The increase of Al concentration in the belowground part resulted from the decreased concentration of essential mineral elements such as Ca and Mg in the aboveground part. In addition, a strong positive correlation(r=0.96, p$lt;0.001) was observed between the dry weight of the seedlings and the molar (Ca+Mg+K)/A1 ratio of the soil solution. When the molar (Ca+Mg+K)/Al ratio was approximately 7.0, the dry weight of the seedlings began to decrease compared with that of the seedlings in the control treatment. The seedlings with the molar (Ca+Mg+K)/Al ratio of 1.0 resulted from approximately 40% growth reduction compared with the control value. The results suggest that the molar (Ca+Mg+K)/Al ratio of the soil solution may be a useful indicator for assessing the critical load of acid deposition.