My feeling is the dogs LIKE to do it. Once they figure it out, they do it more and more.
I had one that would trail a coon through an apple orchard up the tree, to the end of the limb, then drop down where the coon did, even on a cold trail. Those were easy trees to climb, but he got better at it. Pretty soon he was shinnying up branchless trees like a monkey to get to a treed coon.
Its dangerous. They're all better at getting up than getting down. It sure is fun to watch a hound with the drive that causes that, though.
That coondog of mine that climbed was pretty careful to jump out uphill or into water, or whatever he could do to lessen the danger. In the worst case, he would jump down on me to break his fall. He never did hurt himself, but that was just luck and because he died young from other causes.