Impact of some initial forestry practices on the drainage waters from blanket peatlands

Studies were carried out during 1989-1992 at an experimental site in Rumster, Caithness to determine the initial effects, particularly on hydrochemistry, of the establishment of trees on deep peats. Inputs were measured to determine seasonal and between-year variability. Increases in potential interception due to the filtering effect of the maturing forest canopy were assessed. Results indicate that air quality improved during the study, particularly sulphate inputs, and suggest that loadings of marine-derived materials to the soil may be greatly increased in the future by canopy capture. Site disturbances by ploughing and draining have affected nutrient cycles, especially N and S, in both control and forested plots, leading to losses into drainage waters. After a delay of around a year, there were fertilizer losses of applied phosphorus (1-2 kgP ha(-1)) and potassium (25-35 kgK ha(-1)) over the period.