Eric Jaffe has uncovered another study on the benefits of parks. This one addresses a detail lacking in the others: Is there an optimal number of trees?
The most intriguing conclusion to be drawn here is that the size of an urban park isn’t nearly as important as the density of its vegetation.
The less of the city we can see, the better, apparently. That fits with the results of another study I wrote about a while ago. It found that, when it comes to a sense of privacy, it’s not the size of people’s yards that matters, it’s the view.
One problem, though—while thick vegetation may have a psychologically restorative effect, it can also encourage crime. Planting trees and shrubs willy nilly seems like a simple solution to block cities’ ill effects, but clearly urban landscaping needs to be more thought out than that.