Beginner Gardening: Apple trees winter mice damage, 0 by Bandit543

Bandit543 wrote:
I planted 2 Norland Apple trees 3 yrs ago, they are now about 8' tall, and were doing good until I decided to place some straw around the base for winter protection?

As you can see from the picture, mice have chewed the bark all around the base on both of them. Remarkably they still produce leafs this spring? Are these trees salvageable or should I just uproot and replant new ones? I was told that the tree gets its sap & nutrients from just under its bark, and if the bark is gone then the tree will die. So am I wasting my time watching these trees die or can I do something like waxing the area to nurse them, will the tree repair its damage?

Mice never touched the cherry, plum or blueberry trees that I had covered up as well?