Protect the tree now. If not rubbed all the way around, the tree will live. Even if rubbed all the way around, that bootom foot of stump will spout, or new suckers based on your rootstock will grow. It doesn't looked rubbed too bad though. She'll live.
Buck got a spruce tree at home. Dont feel horrible about it, i accidentally sprayed it with roundup, but hosed it off 5 minutes later. Took a bit of a hit, but not horrible from the herbiciade.
Even wrapping it with a blanket or sheet will discourage them until you can grab some fencing.