[Someone]

An example: http://maps.google.com/maps?ll=52.318875,4.976646&spn=0....

#trees per person probably is a better metric. Band-filtered population density, as that filters out high frequencies due to local peaks and low frequencies that denote average wealth of a larger neighborhood, may be an even better one. I guess that might even work for extremely high-rise building as in Dubai. Firstly, the lower floors in such buildings typically are offices, and secondly, I guess the really high buildings will stand less close to other high buildings than the lower skyscrapers that surround it.

[guard-of-terra]

City center might have very low trees per person. Old, crumbling, partially deserted housing might have high trees per person.