As mentioned earlier, the small white birch that you can see behind the black bear serves as a marking tree, sometimes known as a message tree or a bear tree. These are usually, like this one, trees that stand off by themselves in clearings along well-traveled bear trails. Two bear trails intersect at this clearing. I have not read this anywhere, but the marking trees that I have seen have all been fairly small birch trees, although bears will at times use larger trees and even utility poles. Bears mark the trees using their claws most often, as well as their teeth, and their bodies, by rubbing up against the tree. Boars will stand on their back legs to reach as high on the tree as possible, as you can see here from damaged bark high on the tree.