Apple tree bark peeling badly

This isn’t my tree. Its someone on another page im on. The tree is in portland, or.

Not sure on the cause (could have been from a number of things), but I personally would replace the tree or at a minimum regraft the tree. Cut the trunk below the major damage and see if it is healthy if it is then graft if your friend is so inclined. In its current condition it is not going to thrive, likely not even survive with that significant damage. From the picture looks like the tree is already dead from the major wound on up.

I agree and that was basically what I told her. I was just wondering the cause. My guess is sun burn? Does that sound right?

When I see such nice callous forming on a young damaged tree I let it heal itself. In 5 years it will be stronger than it would have been without the damage if it continues to heal.