Tree water uptake enhances nitrogen acquisition in a fertilized boreal forest – but not under nitrogen?poor conditions

Understanding how plant water uptake interacts with acquisition of soil nitrogen (N) and other nutrients is fundamental for predicting responses to a changing environment, but it an area where models disagree. We present novel isotopic labelling approach which reveals spatial patterns N uptake, their interaction, by trees. The stable isotopes 15 2 H were applied small the forest floor in stands high low availability. Uptake surrounding trees was measured. sensitivity quantified statistical modelling. Trees high-N stand acquired twice as much low-N around half dependent on (2 enrichment). In contrast, there no positive effect uptake. conclude that tree only marginally flux toward root surface under conditions conditions, water-associated substantial. results suggest shift strategy conditions.