We are interested in understanding the basic processes and mechanisms underlying the interactions of woody plants (e.g. competition, facilitation, and/or avoidance of competition between plants and different players in the ecosystem) and their potential shifts with global change (i.e. climate change and/or biological invasions of species). Here, our focus lies on the acquisition of nitrogen (N) via the roots and internal N allocation strategies of woody plants, investigating potential general patterns across species (and biomes) at different levels (i.e. from the whole plant via the community to the ecosystem level), and their potential shifts in response to abiotic and/or biotic stressors.