I know of people that hang soap from the trees to keep the deer away... one guy planted 100 trees and not a single one has been touched
X2 It's not 100% deer proof but certainly helps a lot. You can buy unwrapped scented hotel/motel size soaps in for pretty cheap on the internet. Drill a little hole in them & use a small cable tie to attach to a low branch. They will need to be replaced yearly for best results, but it beats doing dryer sheets every two weeks. If the tree isn't completely girdled, it may still survive.