We were cleaning up the orchard last weekend, pruning, weeding, and general cleanup and discovered that mice had burrowed under the mulch and girdled about 1/3 of the apple trees. Some of the roots had been so badly chewed that you could pull the tree out of the ground with one hand. The root looked like a carrot.
We could see the tunnels the mice had used to get to the trees, otherwise they looked perfectly healthy. Beautiful buds swelling up and getting ready to pop open any time. The damage was mostly to trees we planted 3 years ago. All of the trees had a 6' anti-deer fence circling it and a 12" plastic barrier to prevent rabbits from chewing the bark.
So we will replant and propagate some of the plants and see what happens.
Such a disappointment.