Carbon dynamics of a controlled peatland restoration experiment in Norway

Norway has the third greatest extent of peatlands in Europe, after Finland and Sweden. Norwegian peatlands cover nearly 30 000 km² or 7.7 percent of Norway’s land area. However, 6500 km² of these peatlands have been drained for forestry or agriculture and are estimated to emit approximately 6 Mton CO₂ annually, accounting for 11 percent of Norway’s total carbon emissions. In 2016, the Norwegian Environment Agency and the Norwegian Directorate of Agriculture embarked on a peatland restoration plan to reduce greenhouse gas emissions and improve the ecological conditions of drained and degraded peatlands in Norway. Since then, over 100 peatland sites have been restored. However, only one of these sites is being actively monitored to determine the effect of restoration on carbon fluxes, making this site critical to understanding carbon dynamics of restored peatlands in Norway. The site, located in the Regnåsen and Hisåsen Nature Reserve (Trysil Municipality, Innlandet county) consists of two study areas that are sub-catchments of the same watershed, cover approximately 0.5 km², and are separated by 0.5 km. Both areas were drained in the 1960s, with a network of drainage ditches totaling approximately 4000m. One of the areas was restored in 2021 by constructing 318 dams in the drainage ditches, while the other area remains drained as a control. In 2019 eddy covariance towers were installed to track vertical CO₂ and CH₄ fluxes on each site. In addition, DOC, DIC and water discharge measurements were taken to estimate lateral carbon transport, and soil samples were taken to estimate carbon stocks. Preliminary results indicate that CO₂ fluxes have decreased and CH₄ fluxes have increased in the restored site as compared to the drained site, and that vertical carbon fluxes account for over 90% of carbon transport on both sites. This project is coordinated by the LATICE (Land-ATmosphere Interactions in Cold Environments) project at University of Oslo. The results of this study will assist the Norwegian Environment Agency in shaping the next phase of the peatland restoration work in Norway.