I received this Acer palmatum 'Aoyagi' in the mail about a week ago, and just noticed this damage last night. It involves the upper portion of the tree, with a split right down the center. I MIGHT have some wound repair sealant still packed away (I moved recently), but for now I've used surgical tape(hah) to tape this back together, though I don't even know if it's amendable. I really would rather not lose the top half of this tree!

Any opinions/suggestions? Thank you.