Atmospheric sulfate additions and cation leaching in a Douglas fir ecosystem

Precipitation sulfuric acid input was small in comparison to sulfate and cation transfers within the ecosystem studied. Most of the annual incoming hydrogen ions were removed in the forest canopy, presumably through an exchange process. Therefore canopy leaching appears to be most strongly affected by acid rainfall, whereas soil leaching appears to be dominated by mechanisms internal to the ecosystem, such as carbonic acid leaching and sulfur release from decomposing litter.