Simulated H2SO4 rain (pH 3.0, 3.5, 4.0) or control rain (pH 5.6) was applied for 3.5 yr to large lysimeter boxes containing a sulfate-adsorbing forest soil and either red alder (Alnus rubra) or sugar maple (Acer saccharum) seedlings. After removal of the plants and the litter layer, soil samples were obtained at 15-cm intervals to a total depth of 90 cm. Elevated SO4 concentrations caused by the simulated H2SO4 rain were most pronounced for the top 15 cm, but extended down to 45 cm(maple) or 75 cm(alder). There were no effects on SO4 concentrations at a depth of 75 to 90 cm. Elevated concentration of NO3 and extractable Zn throughout the alder systems indicated (1) either increased rates of symbiotic N-fixation or decreased rates of N immobilization; and (2) mobilization of Zn by all acid rain treatments.