Prune back the remaining damaged branch to where it joins the tree. Then just leave it alone. It should be fine and start growing again in spring. If the main trunk was damaged, it will mean another branch will become the dominant leader. It might have a funny shape for a year or two but it should fill in, and with a little selective pruning it should be fine.

As for rooting, that may take a little more work. Rooting woody cuttings usually involves rooting hormone, and/or bottom heat and specific conditions. Here are a couple  of links for more information.

For detailed information on maple propagation, see Propagation of Ornamental Trees, Shrubs, and Woody Vines (second page) from Texas A & M University.

For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service