Base cation deposition to forest in Europe

Summary Base cation deposition represents a major input to forest nutrient pools and is an essential parameter for quantifying critical loads and its exceedances as well as predictions for the recovery of ecosystems from acidification. Lately, concern about removal of base cations from the forest in connection with intensive forest biomass harvesting has become a much discussed issue. It is essential to be able to measure or estimate the base cation deposition to forests with a reasonable accuracy. During the 1980s and 90s a great deal of work was performed in order to determine the input of base cation to forests whereas there has not been much new literature since the 1990s. A workshop was arranged November 21-22, 2012 in order to explore the latest developments and advancements within the area. In this report we summarize the workshop outcomes. The importance of combined methods for measuring or estimating BC deposition was emphasized. European-wide BC modelled maps seems feasible and was considered desirable. A division between different sources (ocean sea-salt spray, Saharan dust, European land born dust and anthropogenic emissions) was suggested. Continued cooperation on a European level should be promoted and different ways for this was discussed.