You need to watch whether they're greedy rooted and that very much depends on the state of your sewers. And unfortunately there's no simple answer to that. I mean even grass will get into a leaking pipe if it has the opportunity. Because remember if the pipe is not actually leaking the tree has no way of knowing that it's there. But scale is the important thing.
Safety is important.
You do want trees that don't have the habit of shedding big branches. It's well worth considering deciduous trees which you give the sun in the winter and the shade in the summer when you really need it, particularly in a small space. So the deciduous tree does let you in the winter sun when you want it and it gives you that shade in summer. One of the nice things about ginkgoes, which has made them an extremely popular street tree throughout the western world, is that they actually drop their leaves very quickly. A liquid amber may drop over a period of three weeks, and while the Chinese legend that the ginkgo drops its leaves in a single night isn't quite true, you are actually only waking up for about a week.