Urban mini-forests

A fun strategy for getting more green space and biodiversity in cities: In cities with wide sidewalks, tear out a strip a couple feet wide, next to the road. Lay in a good supply of soil and other necessaries, and then plant a micro-forest. Instead of those wussy single trees in grating, you'd wind up with a nice sound break between people and cars, as well as a habitat for urban wildlife and a good drainage system. It's a win for everyone.