Q: I had a new sidewalk put in - stamped concrete where they use some acid - and most of my plants in the vicinity are fine but my crabapple has two branches on it that have much smaller leaves. The new sidewalk is about four feet away from the crabapple; the old sidewalk was only two feet away. How badly might the excavation have damaged the roots?

A: Every part of a top of a plant has assigned roots in the ground that are responsible for that part of the tree on top. And when you have partial damage to the root system, there will be partial damage to the corresponding top of that tree that those damaged roots represented. So what you are seeing is a result of that damage. Only time will tell how that tree will respond and recover. The fact that the leaves are undersized tells you that they have been affected. But you'll have to wait and see; there's no magic tonic or potion that you can pour to make the problem go away. It's just going to have to heal; if it's capable of doing that, it will.