I think it is well worth a go but I would not use gaffer tape. I would use webbing or something breathable and tie it in with string. Good luck and I would keep it well watered.
What do these hooligans get out of damaging young trees?

We had rabbit damage that virtually barked a young apple tree......(above the tree guard it was in the snow) taping it as suggested may help, you need a section at least still intact for the rise and fall of the sap
bent over may not help it so I'd do it asap.
also prune the top and take cuttings if you can
good luck

Our Prunus Winter Flowering type had that happen to it, by the wind though. I straightened it out and taped it up and it is still going strong. The broken bit re-attached itself and all one can see now is a thickened piece of trunk.
Let's face it, that is what happens to various hedging plants when they layer a hedge and they survive and grow.

It needs a stake at least 3/4 of the height of the trunk. It could just as easily have been wind damage without proper support. And the strap around the trunk looks to be too tight.

Thanks for that urbanite. Trees these days are only staked to prevent root rock. The tops are allowed to sway in the wind which strengthens the stem. It was not wind damage. The strap around the tree is fine.

I've been planting trees profesionally for 33 years, i do keep up to date with present methods of staking, planting and supporting.

The stake now needs to carry the weight of the tree without the trunk swaying while it heals - any movement in the trunk will reduce the (remote) possibility of it healing. Think of the tree as a broken leg - you can't put it in a plaster cast so you need to provide splints and a crutch.

Again, thank you for that Urbanite. I worked that one out all by myself.

Apologies Badfish, if it sounds like I'm teaching my grandmother to suck eggs, but you asked the question! And other amateur gardeners might have been interested to know why I had made the suggestion for the longer stake.

as there is still the translocating tissues it should recover but unlikely to 'heal' in the true sense. tape up with a porous material. medical gauze with a tape to hold it all together. it will have a callus /scar tissue form though.