This is what a tree graft failure looks like on a Japanese maple.
Some beginner gardeners might have blamed a rodent for eating away at the bark but it’s really a problem with a graft that’s beginning to fail and kill the tree after (about) 8 years in the ground.
Can It Be Fixed?
Unfortunately, no. This tree is simply slowly dying from the top down and I’ll be pruning off the dead branches over the next few years (at least I hope I have another few years) 🙂
Isn’t There A Plant Guarantee?
If this had happened in the first year or two, then yes, you could ask for a refund.
This tree is 8-ish years old in our garden. Any warranty has long expired.