Last changed: 02 June 2023

The IM site, called F1, is one of several small catchments around lake Gårdsjön which have been thoroughly investigated from both lake and forest point of view since around 1970. The most widely known project is probably the "Roof Project" during the 1990´s. Responsible for the research is the IVL Swedish Environmental Research Institute Ltd. The IM-monitoring started in 1991. Gårdsjön is situated about 7 km straight to the east of Stenungsund, south of the road Ucklum-Västerlanda in the Svartedalen wilderness area.


  • International code: SE04
  • Latitude/longitude: N58°03´ E12°01´
  • Swedish Grid: 644250/127600
  • County: Västra Götalands län (OPR)
  • Municipality: Stenungsund
  • Land owner: Gårdsjöstiftelsen
  • Size of catchment: 3,7 ha
  • Long-term average precipitation (not corrected): about 1140 mm
  • Long-term average temperature: about +6,7°C
  • Snow cover: about 55 days
  • Length of vegetation period (mean temp. > +5°C): about 200 days
  • Biome: Boreonemoral
  • Dominant vegetation type: Norway spruce - Vaccinium myrtillus and mixed coniferous – Vaccinium myrtillus forest/
  • Dominant soil type: podsol
  • Bedrock: young gneissic granodiorite
  • Air pollutant deposition: substantial, N c:a 19 kg, S c:a 20 kg/ha/year
  • Land-use history: Probably grazed woodland for centuries before clear-felling 1900-1910 and subsequent forest tree planting and thinning (1968). Grazing was suspended around 1950. In 1980 roughly a half hectar was clear-felled and planted with pine. During the 1990´s clear-felling took place up to the watershed in the southwest and northeast and a timber road was opened straight through the area in an east-west direction.