Downward trends of sulphur deposition to Danish Spruce forest

Determination of sulphur deposition to Danish forest and documentation of possible trends during an eight-year period was one of the aims of this study. Measurements were carried out at two sites in Denmark with even-aged Norway Spruce plantations. A western site is situated 15 km from the North Sea in the sandy soils of West Jutland, and a site 250 km east of this is situated in the loamy soils of Sealand. Subsequent measurements of gases, aerosols, precipitation and throughfall from June 1985 to June 1993 make it possible to follow a decrease in concentrations of atmospheric sulphur dioxide and sulphate in precipitation as well as in the deposition of sulphur compounds to the forest ecosystem. Taking throughfall sulphur fluxes as an estimate for atmospheric deposition to the forest we calculated the yearly average SO2 dry deposition velocity, Vd, to be 1.1 cm s−1 at the western site and 1.0 cm s−1 at the eastern site.