ABSTRACT
This chapter starts with outlining the most important theories regarding associations between natural environments and health, often attributed to restoration from mental fatigue and stress recovery. It then explains the importance of urban green spaces for physical activity and social interactions. Following a section on how biodiverse urban greenery can promote healthy immune system development, the chapter summarises how urban ecosystem services contribute to human health. It further introduces and categorises the various health effects of urban forests and other urban green spaces, outlining pathways like stress recovery, physical activity, social cohesion, as well as mechanistic, biological and ecosystem explanations and services. For urban ecosystems and populations to survive, novel methods and transdisciplinary efforts are required. Within such efforts scientists must no longer rely on reductionism and single risk factor modelling, but systems science is required, in which policy makers, practitioners, and stakeholders are involved from problem formulation to solution.
