It is a good question and one I am not sure I can adequately answer. However, since I have done the activity in question in the past , I will share my reasons for doing so.
It really comes down to two reasons for me. The first reason is mostly for practicality. I typically carry a full size pistol in a Safariland ALS hoster on my hip. When I am bushwhacking (usually when I am hunting or just plain exploring), that package tends to be rather cumbersome due to its bulk and can get hung up on branches, underbrush, etc. Really annoying! So pistol will get tossed into the pack until I come to clearer areas to hike in. Now I know that I can resolve this by:
1.) Changing my mode of carry, which I have been looking at making a chest rig which will ideally not be in the way.
2.) Scaling down the size of the overall package. ie. More compact pistol, lower profile holster, etc.
3.) Simply getting/making a different holster that hugs the body better vs. projecting as much as the ALS holster does.
The second reason tends to not be much of a factor as I try not to frequent many popular and/or populated areas anymore. But in the past, when there is a reasonable expectation that I will encounter a lot of other hikers, I simply avoid the potential hassle that open carrying a large pistol can cause and stow it in my pack. I recognize that it renders the pistol rather useless if I were to need it in a pinch but I make no attempt to conceal the large knife I usually carry (knives seem to be an acceptable tool in the wilderness, regardless of size) and I am also not a small man, so if someone wanted to get the drop on me, they would have to do just that. Animals are less of a concern really, though as I said earlier, we do have a rather healthy black bear and cougar population here in the NW.
All in all, I can certainly improve my mode of carry in the woods. My reasons aren't necessarily good ones, but they are honest. I never not take my pistol as I believe that having one and not needing it is the best course of action regardless.