I have about ten trees that look just like that. My trees had guards but they tunneled in. If you excavate, it may also have root damage. When I replant, I dig a big hole and fill with 80% Gravel. Maybe it will slow the Voles down.
That makes the goat damage we had look minor, and goats (bad as they can be at escaping) are easier to contain.
Inarching with other rootstock(s) might save the tree, but replacing it might be less work, and money.
We bridge grafted a damaged tree, but I don’t see any low bark to slip scions under.
you could try inarching to multiple thin-caliper rootstoc as others have mentioned, but might be too much work. If you decide to ply this route, would be best to prune as many of the canopy’s branches(as much as you could bear to lose–painful that might be), as it increases chances of survival.
some pics were shown on this thread-- What "grafting" technique is this?
also best to wrap the exposed sapwood with saran or parafilm to minimize exposure.
also notable is that during spring, when trees start to leaf out, movement of carbs/proteins is from rootstoc to buds. Your apple tree might do well initially—until the sugars/proteins, etc have been used, so the rootstoc soon starves since sapwood xylem is practically a one-way conduit. Inarching will give the tree new roots, if the callus formation is too far and isn’t fast enough to connect phloem to the original rootstoc.
bark-grafting at the proximal site of the damaged bark of the original rootstoc may also help, to somehow provide the old rootstoc access to solar panels – the subsequent foliage of the bark-grafts.
OOps…sorry I had two topics open. With the girdled tree…cut it down and hope rootstock sends up a great sprout (which can be used for budding late summer or grafting next winter. (and if not too far along, you can save scions from the top to graft somewhere else this spring).
I know that voles are small and I’ve read that they’re poor climbers so if someone showed me this tree I’d say it was a small rabbit…or something…but I wouldn’t guess voles. If all commenters agree that this is voles, this is an eye-opener for me. I’m very new at orcharding but I have a very ‘healthy’ vole population and everything I have planted has a 2ft tall cage around it, 1ft underground and 1ft above ground, of hardware cloth, aka metal screen. I’ve never had damage to anything…that I know of. Before orcharding, the voles would wreak havoc on all garden items, small trees, etc. That’s why I knew to protect the trees. I often see vole holes right at the perimeter of the little cages; I should dig down a couple of them to see if they make it under the ‘fence.’
It’s unfortunate about your tree; it’s looks like it had a healthy start.
Edit: the OP reminds us of snow…the snow builds up and the voles tunnel in it and walk on it. That doesn’t seem to happen here much (seldom snows much) but I’ve heard many describe it before.
In this case its the snow that lets them get up that far. In the winter here either you protect the tree or clear the snow away from it. They don’t gnaw as much on trees where there is nothing for them to hide in.
That sure looks like vole damage to me. They will girdle trees easily. Interestingly, I don’t have much vole damage in my backyard orchard in a subdivision, but out in the “country” they are much more prevalent and will honeycomb the ground under the trees if unopposed.
I use labeled bait just before hard winter sets in. I bait each active entrance. I feel bad poisoning them, but it works.
One of my favorite books as a kid was Mrs. Frisby and the Rats of Nimh. Hard to think about that great book and try to defend one’s orchard against rodents at the same time.
I have six girdled trees in my orchard that I didn’t protect. They have a bunch of chips up to 1/2" laying at the bases. Would those be voles too? I’m getting scared that voles might have got behind my tube guards and my losses will be more than six. I will have to go out and look when the snow lets up. I know we have them I see them under the bird feeder with all their holes coming up out of the snow to eat the seeds. I also caught one in a mouse trap in my garage.