Home Improvement Questions? Ask a Handyman for Answers
Hi. It can if the wood is not too dry. You do it with the same technique using for grafting and you seal with wax. A large branch will need a lot of support (metal wire work the best but it is better to use some cloth under it to protect the bark. It will take a good year, perhaps more to heal and the branch will stay fragile for at least 10 year.
There must not be any air gap of the water won't be able to climb in it. If it was not in the crotch, i would advise to freshly cut each part of the branch to make sure fibers connect well.
If the wound is not that big, it may be better to let the tree heal over it (without any sealing) and trow the branch away. Mapple are very good at growing back branch (they developped that to not be killed by deer browsing).
It separated pretty clean and the tree is still young. I would say let it as it is and the wound will close after some year, do not seal it.
Because some mechanical strenght was removed from that leader, i would use a tutor until the wound folding give it back enough rigidity.
You may also prune some 5-6 inch from long stems/branches so that wind do not have so much leverage on them (especially when they are all wet at the same time).
If you still want to attempt a grafting, you will need to cut the branch in the bucket to 15 inches max because there is no way that enough sap will be able to feed all that foilage with just a few wood fiber contact.