Abstract Investigations were carried out on the impact on root vitality and distribution of fine roots, in catchments subjected to increased nitrogen deposition (G2 NITREX), decreased nitrogen and sulphur deposition (G1 ROOF), and ambient levels of nitrogen and sulphur deposition (F1 CONTROL) at Lake Gårdsjön basin, southwestern Sweden. Root studies were carried out on sequential cores and ingrowth cores. The fine roots were separated into three vitality classes. Estimated root variables displayed a high variability between samples from the same area and year, indicating a high heterogeneity within the catchments. Year-to-year changes in the amount of fine roots of different vitality classes which occurred in all catchment areas, were probably related to natural variations in climatic conditions. The bulk of the fine roots (living+dead roots less than 1 mm in diameter) was found in the FH layer (45–82%). Signs of an increased percentage of living fine roots in the organic soil layer in the G1 ROOF catchment suggest that growth conditions for fine roots are improved by reducing N and S deposition. Results from the G2 NITREX catchment suggest that increased nitrogen deposition may reduce the total amount of fine roots.