Looking out my home office window, I see nothing but trees. There's a thousand feet of trees in any direction before you get to the next house. But I seriously

Looking out my home office window, I see nothing but trees. There's a thousand feet of trees in any direction before you get to the next house. But I seriously doubt my neighborhood has become uber-wealthy. More like we just live in the woods. :) I say that not to be snarky, but as a way of questioning the methodology being used here. How do you classify "urban"? What about locations where trees grow naturally? Is the relationship causal or just random correlation? How about cities that were built in a loose fashion in a naturally-wooded area? Those in the desert? And so on. I note that one study showed if you wanted to find the most dangerous parts of cities, measure the density of liquor stores. I guess next time I'm in a city with no trees and a lot of liquor stores I'll know to be really careful.