Konijnendijk reports that “Having trees and other vegetation in sight from one’s home, place of work, or school has important mental health and performance benefits. . . . With public green spaces in proximity to one’s home stimulates regular use of these areas and results in positive impacts on mental, physical, and social health. After analyzing existing guidelines and rules for urban green space planning and provision, a new, comprehensive guideline is presented, known as the ‘3–30–300 rule’ for urban…