Squirrel Damage to Cedar Tree - Seeking advice

Has anyone lost a mature tree due to damage by squirrels?  We have a 70 ft. tall cedar tree in our yard.  For some reason this year, for the first time, the squirrels decided to take up residence.  When I first saw the squirrels building the nest, I didn't think much of it.  However, they are quickly stripping away all the bark from the tree.  I read online that they use the bark to line their nest.  This has happened in just a few days time and we are concerned about the damage to our tree.  I've attached a photo showing the damage.  Yesterday we bought Critter Ridder and put it all around the base of the tree, and also sprayed the liquid version directly on the trunk.  The repellent does not appear to have stopped them, but perhaps we need to give it more time. I left a message for the arborist from Sav-a-Tree this afternoon asking if there is a commercial strength product that they might suggest.  In addition, we have placed chicken wire fencing around the tree.  Does anyone have experience in getting rid of squirrels once they have built a nest, or advice on steps we can take to help the tree recover?   If so, we'd very much appreciate your feedback.  Thank you.  

I apologize for the sideways pic.  I can't figure out how to rotate the pic.