Mice / voles will eat old trees. We lost 3 BIG old trees - probably 35 - 40 years old. They got completely girdled one winter with deep snow and crust on it. Gonzo !! Bark was rough - it didn't matter. Stripped right down to white wood.
War on voles / mice ?? Don't shoot owls, hawks, snakes, foxes. We tried pellets and they didn't even touch them. Build nesting boxes/structures to encourage barn owls to move in.