Uhlířská (Jizerské Mts.) is a typical mountain catchment underlain by acidic bedrock and strongly acidified during the second half of the 20th century. Two thirds of the catchment were deforested in 1980s and subsequently reforested by Norway spruce (Picela abies) monoculture. Research here has been mostly focused on fluxes of ecologically important elements and water. The monitored characteristics include bulk and throughfall precipitation amount and chemistry, runoff amount and chemistry as well as soil chemistry, forest biomass and element pools but also plant community composition. Biogeochemical (MAGIC) and hydrological models (BROOK90) have been applied to predict future chemistry and hydrology under different scenarios of atmospheric deposition, forest growth and climate change. Hydrological processes of surface and subsurface runoff formation are studied in the catchment as a whole and in detail at the experimental hillslope Tomšovka using standard hydrologic and isotopic methods, incl. water transit time evaluation and groundwater age dating. Hydrology research focuses on water and heat flux in soil profile as well as on processes in the soil-plant-atmosphere system. Geophysical methods are used to reveal subsurface structures.