Answer: Unfortunately, this may be a lost cause. Since it snapped above the graft, there is a very faint chance you might be able to salvage it by training the new growth that emerges above the graft and removing any growth appearing below the graft. It should grow quickly because it has such a large established root system. It may be nearly impossible to create a decently shaped or structured tree, so it might be preferable to start again with a new tree. You might also be able to root some tip cuttings taken from the top, but these will take quite some time to reach tree size again.
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