CTyler,
I guess there are ways to protect trees from deer that are less trouble and expense, but I put a five foot circle of five foot welded wire around every fruit and nut tree I want to keep Bambi from ruining. Liquid Fence works, as some other repellents probably do, but you have to remember to keep spraying, and a desperate deer would probably ignore it anyway. When my trees are big enough that a deer is unlikely to kill them or turn them into shrubs, I take off the fence and then wrap the trunk in wire to keep them from being rubbed. Eventually I take off the trunk wrap when the tree is less of a rubbing target or big enough to take a little rubbing. I have at least as much money in fence and t-posts as I do in trees.
A few years ago, I planted about 25 each of black walnut and pecan seedlings from the conservation department. I figured deer would get some of the pecans but would probably leave the black walnut alone. There are none of those trees left. When they were all either gone or becoming shrubs, I turned that field back to hay.
Chuck
