In this state, brick mailboxes and similar features can become a big liability issue. If a speeding car hits one and the people or the car are hurt or damaged, it's the homeowners fault. In most places, you might own the frontage, the area between the sidewalk and the street, but your city or county government has control over that area. And, yes, our city does plan the trees that they want and they also trim them.
Beyond what happens to you if there is an accident in which your brick structure is involved, the city can make you tear it down or tear it down for you and bill you. Certainly they will try to work with homeowners, but ultimately, they have liability issues too.
Please don't "shoot the messenger". I didn't comment about what I thought. But you should check with your city or township or county government to see what the rules are before you spend a lot of money for nothing.