I'm in New Hampshire (USA), and we had an unexpectedly early snowstorm. My beautiful Star Magnolia had not yet dropped its' leaves and the weight of 10" of snow broke off the top half of the main leader branch. The branch broke off at a main fork, and the two other main vertical branches are a bit bent outward (due to the snow weight they suffered through). Overall, the tree is approximately 18 feet tall. Is there anything I should do for the tree, such as pruning or tying up the remaining two vertical branches, or just let it take care of itself? It's an otherwise very healthy 12 year-old tree.
Prune to make cuts cleaner and better located than the random breaks if possible (investigate: natural target pruning). Attempt to encourage a new leader from remaining branches. Expect the locations of the breaks or cuts to produce sucker sprouts (AKA epicormic shoots) and manage them in the future. If it is 18 feet tall you may want to consider hiring a competent professional to do it for you.
@ jimmyq: Thanks for the response. The branch broke right at a "V", leaving nothing left to prune off. I'll keep my eye out for sucker growth in the spring and prune that as needed. There are two other nearly vertical major limbs left, so hopefully they will continue their strong growth and send out some side branches to fill in the hole in the middle.
