This is more common than you might think :-) J. maples have very thin bark and squirrels can use it for food in winter but more often strip it off in spring for nesting material.

Generally it causes no more than cosmetic damage and can eventually grow back. However, if the bark is removed uniformly from all around the trunk - the complete circumference - it could compromise the tree's ability to transport nutrients and that could become a very serious problem. Removal of the bark from around the branches is somewhat less serious, although it could seriously damage that specific branch, but not the entire tree.

Wrapping the trunk or branches loosely with chicken wire or a designated tree wrap can help - it certainly impedes the squirrels' ability to get to and remove bark. But unless you can provide photos, it's hard to say how much damage has been done and if the tree will survive it.

Thanks for your follow up - it would be a great relief if this caused only cosmetic damage.

I just took a picture of the tree, but am not sure how to upload. If you can tell me how I will gladly post it.

Our Maple is about 25' high and 20' wide. The lower 6' of the tree (its main trunk and bottom of its large branches) is largely untouched; the squirrels have stripped off almost everything above that point, virtually to the tips of the branches. They have left piles of bark at the base of the tree :/

After a dramatic dropoff in the amount of squirrels in our neighborhood, they are back with a vengence. This Fall their population easily tripled what it has been over the past five years or so.

There are several repellents available that might help keep them away from the tree. Make sure it has pepper or pepper oil in it, as that's what teaches them not to chew on your tree..