Not sure where you live, but I grew up in a midwest city that participated in the Tree City USA program and it was pretty nice. Didn't have the whole surrounded by smaller plants which is even better, but at least the trees helped with shade and keeping some of the grass and other small plants from completely evaporating in the summer sun.
I'm sure many other countries have their own comparable programs.
It's not trees in Japanese urban cities (they keep getting cut yikes) but ones planted using Japanese botanist method. It plants native and climate appropriate species to grow climax community on the go in packed manner. In theory, once established 'the forests' have stable ecosystem and don't need external intervention. The theory now considered working, though the timespan to see if it truly works is centuries, and has been adopted over south Asia, east Asia and Europe.