Sulphur Dioxide Uptake and the Leaching of Sulphates from a Pine Forest

The average daily deposition velocity of sulphur dioxide onto a pine forest canopy in the UK was estimated using a flux gradient method. In dry summer the deposition velocity was estimated to be 0-004 m s1. Transfer was effected by the surface resistance rc. Comparison of rc for SO2 with that for water vapour transfer suggests that stomatal control may be an important influence on the rate of deposition. Comparison of the sulphate content of rainwater, after passing through a forest canopy, with the sulphate supplied via dry deposition indicates that significant leaching may occur at high rainfall and that rainfall enrichment is proportional to the airborne concentration of sulphur dioxide.