A long-term field experiment in northern Sweden
In the long-term field experiment E171 Åsele in northern Sweden, we are investigating effects of forest fertilisation at varying intensities, including effects on tree growth, wood properties, climate benefits, the mycorrhizal community, field vegetation, mosses and lichens. The field experiment was established in 1982. Over the following 42 years, a total of 0 to 3,300 kg of nitrogen per hectare has been applied to study plots. The highest application rate corresponds to 22 standard single fertiliser applications. Extensive measurements were taken before the study plots were clearcut in 2025.
The objectives of the investigations are to determine how nitrogen fertilisation at different intensities has affected:
- tree growth and biomass,
- wood properties,
- total carbon and nitrogen stocks of the forest ecosystem,
- greenhouse gas emissions from the soil following final felling and immediately after fertilisation (the latter at a separate site close by),
- the risk of nutrient leaching before and after clearcutting,
- species composition and species richness of mycorrhizae and various functional groups,
- composition and diversity of field and bottom vegetation
Tree no. 29 in one of the study plots. Photo Eva Ring
One of the 21 study plots after clearcutting. Photo Eva Ring
Before clearcutting, soil samples were collected for chemical analysis and analysis of fungal communities. Photo Monica Strömgren
Wood samples taken from Scots pine trees in the study plots. Photo Eva Ring
Publications
Jacobson, S. and F. Pettersson (2010). An assessment of different fertilization regimes in three boreal coniferous stands. Silva Fennica 44(5): article id 123.
Projektavslut: Fyra decennier av gödsling i Åsele – Skogforsk (in swedish)
Research funding from
Swedish Energy Agency, Bio+-programme
(Project P2024-03069: Forest production, climate benefits, and sustainability? Effects of 42 years of nitrogen fertilisation at a field site in Västerbotten County
Skogssällskapet
Project 2026-1531: Kort- och långsiktiga effekter av kvävegödsling på växthusgasavgång och kväveläckage i skogsmark (in swedish)
Carl Tryggers Stiftelse
Project CTS 25–4087: Kväveutlakning efter avverkning av tidigare gödslad skog: -riskbedömning genom studier i fältförsök.
Project CTS 25–4166: Utrustning för att mäta metan- och lustgasavgång från skogsmark direkt i fält för mer tillförlitliga resultat.
Uponor
Custom-made collars for measuring greenhouse gas emissions
Landowner
SCA (We are driven by the force of the forest – SCA) hosts the field site on their land and is also a project partner. SCA has, in various ways, facilitated the collection of data relating to the felling.