The 3-30-300 rule: a simple tree test most cities fail

Urban forester Cecil Konijnendijk’s 3-30-300 rule has become a popular shorthand for measuring fair access to nature: every home, school, and workplace should have a view of at least three trees, sit in a neighborhood with 30% canopy cover, and be within 300 meters of a park. The benchmark is catchy and easy to grasp, which has helped it spread to cities like Florence, Fort Collins, Haarlem, and Saanich. The problem is that almost nobody actually meets it.

A study of 862 European cities found that only about half the population can see three trees from a window, with southern Europe faring worst—just one in ten residents in Valencia clear that bar. The 30% canopy target is the real bottleneck: only a third of Europeans live somewhere that hits it, and the cities that do tend to be small. The 300-meter park rule is the most commonly satisfied, met by roughly 60% of residents. Stack all three together and only 14% of Europeans pass, while 21% fail every criterion. Across eight major global cities tested separately, only Singapore qualified.

The stakes are concrete rather than aesthetic. Reaching 30% canopy across European cities could prevent an estimated 2,644 heat deaths each summer (and researchers in Madison, Wisconsin argue meaningful cooling really begins at 40%), while residents in compliant areas report better mental health and lower medication use. The piece frames these as minimum standards, not aspirations, and notes that shade—like other amenities—too often tracks wealth. The researchers’ prescription is blunt: tear up the asphalt and plant trees.