I've been suspicious that large animals may be able to pass through spruces, because they seem to do it occasionally when chasing them. But I have no proof. I'm interested to know the truth on this... sort of. Many things that are uncertain in the game are part of the greatness of it, and I don't want to know all the secrets. Discussion of what can go through/over fences has been ongoing for ever, but trees... I don't remember a definite conclusion.
I've never seen this happen. I've also decently often chased animals into my trap fences, and every time this has happened they've stuck in a trap, i.e. run along the fence, found a gap, and got caught in the trap in the gap. So, they
haven't run through spruce trees.
Sometimes it seems the game will, when I zoom into a tile, drop me on top of a tree. The way I noticed this is that when I'm hunting, when I get zoomed in I drop all my non-combat items, leave a map marker, and then go on my hunt unencumbered. When I go back to my pile of goods, it may be on the same tile as a tree, despite me not pushing it into a tree. So, it probably means that I didn't notice that as I zoomed in, I was placed on a tree.