IntroductionUrbanization is progressing at a rapid rate around the globe.Over half of humanity now lives in urban areas. By 2050 this propor-tion is expected to exceed 70% . This unprecedentedshift from rural to urban living is associated with a significantdecrease in exposure to natural environments. Coincident with urbanization,there is also evidence of an increase in the worldwide preva-lence of mental disorders. Growing evidence suggests that these twotrends may be linked, with decreased exposure to nature caus-ing changes in psychological functioning