As much as I see the appeal to take initiative and plant a tree on your own (I personally dream of turning my backyard into a mini meadow), I would really encourage you to talk to the city instead. Cities often work with arborists to determine the best tree for a location, that will work with the soil type, water availability, be appropriately hardy for the environment, etc., but most importantly, won't have a root system that will cause damage to sidewalks, building foundations, etc. Additionally, you might want to look into whether or not your city is a participating member of Tree City USA. If they aren't, maybe you can find a way to help encourage them to join. After all, one tree on a corner is great. A tree on every corner though? That's a thing of beauty.I don't want to ask permission from the city: I wanna buy a sapling that'll grow into something massive. I think it would look so cool.