Can you see three trees?

The 3-30-300 rule is an urban standard requiring residents to see three trees from their home, live in neighborhoods with 30% tree cover, and be within 300 meters of a park—a framework increasingly adopted by cities worldwide to ensure equitable access to nature. A study of 862 European cities found that only about half the population meets the first criterion, roughly one-third meet the tree-cover goal, while nearly 60% achieve the park-access requirement, with northern Europe generally outperforming southern regions. Research shows these standards have measurable health benefits, including preventing thousands of heat deaths and improving mental and physical well-being.