This is damage from a native woodpecker called a Yellow-bellied Sapsucker. It is protected under the migratory bird act. They eat sap and insects and often don't cause enough damaged to harm the trees and they recover. There isn't anything you can do to deter it since if you try to cover it, the bird will likely move to another part of the tree, or a different tree on your property. They tend to move on once it gets hot in the summer, moving more to the north west of Maryland. They could return to your yard next winter.

Emily