Walking through the forest I often see bear trees. Bears (black bears [Ursus americanus] in our area) will pull away the bark of living conifers to get at the juicy substance on the wood or to uncover grubs and other insects. Bears will also claw at dead trees or fallen logs to reach grubs and insects. Black bears can remove tree bark from four to eight feet off of the ground.
Another type of bear tree is one where bears will rub against a tree, usually a tree along a trail or other prominent point. The bear often will repeatedly rub against the same tree until the bark begins to fall off. In this case hairs are often found attached to the bark or sticking to the tree pitch. It is not certain if this “rubbing” bear tree is used as a signal or scent post, but generally it is thought to simply be a place for the bear to comfortably scratch itself.
The pictured bear trees are at Burney Falls State Park (Shasta county CA). Six foot tall Leonard is standing next to one bear tree to show how high the bears can claw. The aggressive clawing to reach the tree interior and lack of hairs indicate to me that food was the object of these bear clawings.