It is commonly believed that fine texture soils developed on carbonateparent material are well buffered from possible acidification. There areno data, however, documenting resistance of such soils to acidicdeposition exposure on a time scale longer than 30-40 years.In this paper we employed a rare opportunity of directly testinglong-term buffering capacity of 19th century forest soils developedon calcareous silt loam. A comparison of chemical analysis of archivedsoils with modern soils collected from the same locations ~100 yearslater indicate varying degrees of acidification of forest soils in taiga andthe forest steppe regions. Reforestation and increases in precipitationcontributed to acidification, as well as acidic deposition. The acidificationof forest soil was detected through decreases in soil pH, and changesin concentrations of exchangeable calcium and aluminum, whichcorresponded with changes in communities of soil microfauna. Althoughacidification was found at all 3 locations that were analyzed, the trendsin soil chemistry were greatest where the highest loading of acidicdeposition had taken place.