Last month we explained how parks can restore much of the mental fatigue imposed on our brains by the busy city. The psychological evidence for this concept, known as the "attention restoration theory," is quite clear. What would be great to know, as I noted at the end of that post, is precisely how many trees it takes to recover the cognitive strains of urban life.
Well sometimes the gods of semi-obscure-hybrid-behavior-nature-academic-publications listen to your calls. In an upcoming issue of the journal Landscape and Urban Planning, a group of Finnish researchers describe recent work that just so happens to address our exact curiosity. They conclude that restoration reaches peak potential when every inch of the city — which they term the "urban matrix" — escapes our vision: