I have a row of very mature Arborvitae or cedars that line my driveway. Trunks are about 2 to 3 feet in diameter at ground level. I noticed that the bark looks as if it was rubbed off by a deer but this isn't the cause as we don't have deer in our yard and some of the rubbings are 10 feet up (unless we have really big deer). My suspicion is that squirrels are stripping the bark either to eat or for nesting material. Is there anything I can put on the trees to discourage this? The bark isn't rubbed all the way through, just enough to expose lighter colored pinkish bark. I'm concerned if it continues that it could eventually damage the trees.