Nitrogen uptake capacity of European beech (Fagus sylvatica L.) only partially depends on tree age

Abstract Key message On calcareous soil, European beech roots prefer organic nitrogen, but only arginine and not glutamine or inorganic nitrogen. Nitrogen (N) acquisition is a major factor determining the processes mechanisms involved in tree productivity, development, competitiveness. However, few studies have investigated changes N capturing with age. We conducted 15 incubation experiments to quantify (i.e. ammonium nitrate) glutamine-N arginine-N) net capacity of trees five age classes. Our results showed no general pattern, that uptake was rather source-specific. Inorganic did differ between classes at all. Arginine-N highest youngest oldest stands reflecting high demand by seedlings for root foraging biomass production despite low internal storage capacities older reproduction. Organic preferred over regardless Overall, our study shows significance sources trees.