Issues with cliffs?

[dustdevilr1]

I'm not sure if this is a bug or the way the game is supposed to work but at least some animals can go over/through the cliffs just fine. I believe I've seen rabbits and foxes do it. Also, if you fell a tree and it happens to land on a cliff, there seems to be no way to do anything to the intersecting portion.

[Lusewing]

I have a simler problem with a log in my wall, looks like I just have to wait for the wall to rot before I can get it.

[Onionfighter]

Rabbits chickens, and moths can move through walls and cliffs. Foxes shouldn't be able to do that.