My main topic of interest is plant nitrogen nutrition. Boreal forests are often nitrogen limited and it was assumed this was because of a limitation of production of inorganic nitrogen forms in the cold and acid soils of this biome. Research within my group has contributed to a change in this paradigm as it has shown that plants in general, and forest plants in particular utilise a range of organic nitrogen forms as well. Through developing new methodology for low-invasive monitoring of soil nitrogen dynamics we have also shown that organic nitrogen dominate the soil solution of boreal forest soils. These discoveries have also given a foundation for the development of a new type of nitrogen fertilizers.