Can you post a photo?

Otherwise, put a cage round it to stop it repeating the damage.

Resin

This is strictly anecdotal, no scientific evidence to back it up, so take it as a "what I did that worked" story.

I have a row of Leyland Cypress that the deer started rubbing a year or so after planting. Three of them were damaged on one side with lots of bark either badly bruised or rubbed off completely. I took a couple of bars of Irish Spring soap, the original strong scented kind, cut them up into pieces, and tied each piece into a section of old pantyhose which I hung in the trees at deer-nose height. Although the deer still come through, they have stayed away from the trees. I replace the soap every year in late summer to keep the scent fresh. It worked for me.

If the tree has a side branch below where the rub damage is, you will be fine--the tree will have this branch grow upright in a couple of years and you will never know there was any damage in a few years. For a while the base of the trunk may not seem straight, but over time as the trunk grows thicker, it will not really be noticeable.

If there are several (a whorl) of branches below the damaged part, just let them all grow. If after three years, two or more seem to be of equal vigor, shorten all but one.

If the damage to the trunk is half way round or less, leave the tree alone--it will grow new wood over the wound and be just fine. If the damage is more than halfway around, cut the part above the damage off and let the tree grow as I described above.

I have had this happen to a number of my white pines. Of course you need to protect it from now on.

--Spruce

Are they "marking" their territory? Or are they rubbing felt off their antlers?

I have some young clump birch - and the main trunk, less than 1 inch caliper has deer rubbing around 95% of the bark. Its such a shame as the bark is best part of the beauty of this tree. Is there any chance this little 5% strip of bark will enable that trunk to survive?

It might just be enough, though I'd not be too surprised if the top dies and it recovers by sending up new branches from below the damage. As above, fence the tree to prevent further damage.

Resin

Chester, my advice is to wait and see what the spring/next year brings - it may be fine and may not, but dealing with it right now is not necessary - except for blocking the deer's access.

If the trunk dies back, you may be able to get a better tree/clump by cutting that trunk to the ground, and letting one of the subsequent sprouts become a new trunk, rubbing off the rest or the sprouts - I can almost guarantee that you will get sprouts from the roots! One of the existing, subordinate trunks can become the new main trunk. That way, you will start with a "clean" trunk, rather than one with an obvious crook/jog in it where a new leader sprouted on the trunk, and grew upward, or an existing branch started growing more vertically than horizontally. You may be lucky, and there may not be too obvious a difference - and in a few years, it won't show much at all, if any. In which case, you need to do nothing except make sure that only one branch becomes the new leader - multiple leaders are not a good idea.

Will White pine sprout from a stump? I know most pines won't.

White Pine won't. The above comments were about Chester Grant's deer-damaged birch (post #7), which should do so.

Resin

As an update to my 95% damaged river birch - the two nearby trees less severely affected (one was 50% the other 25%) by the deer antlers have leafed out. The badly 95% damaged one has green buds but they are yet to leaf.

My guess is that the moisture needed to move up the tree to the buds is constrained by the remaining 3/8 inch strip of bark so maybe they will leaf in time. I suppose giving extra water might help the process?

something i do which may be useful... first pay close attention to your trees, most dont until its too late, at first signs of rubbing i trim off the lower branches usually already destroyed, to reveal the trunk 2 to 3 ft. more or less depending on size, and then cover or wrap with a length of plastic corrugated drainage tubing. ive had many trees more than 50% scraped survive.