Deer ate the leaves off a recently planted red maple tree. Is the tree permanently damaged or will the tree continue to grow? What should I do?
If you are living in the northern hemisphere, I assume you are, then there is a very good chance your tree will be fine. This time of year this tree is putting out new growth. The tree has saved up energy over the winter and could easily put out new growth again.
Get a fence around the tree of chicken wire and far enough from the tree so that the deer will have a tough time pushing it over or trying to eat those yummy baby leaves through the wire. I always put out a few bales of hay for the deer so they aren't interested in my landscape plants that are surrounded by fences and sensor lights and sensor sprinklers. The hay does NOT attract the deer. They will be at your home salivating over the new leaves no matter what. A few bales of hay (you can even get cheap OLD bales of hay/alfalfa that they will love and be fine eating). I've never had to use more than 3 bales per season. And I always live where there are lots of deer, elk, raccoon, rabbits...cougars, bobcat...please send a picture of the damage but you most certainly have a good chance at recovery.
The most important thing to do is "just wait". Either the tree will start to grow a new crop of leaves quickly, or it won't.
If nothing happens within a month, don't bother to wait to "see if it will grow again next year" - just get rid of it.
You might also consider filling your freezer with fresh venison ;)