Tree cover is great but I wish cities would just consider shade a bit more. As the world heats up, it's insane that so many places humans need to be for extended amounts of time have enough shade for a handful of people at best and often nothing. I'm thinking long sidewalks, waiting areas, playgrounds.

Long sidewalks could also be covered with solar roofs for shade, but trees have the advantage that they don't block sunlight in winter without leaves, when sun is nice (in colder climates).