^^^^
Oh yeah.
I've gotten through much of it already, very engaging and full of ticklish information to ponder.
One thing Bipto, on that firewood question: Right. Who knows for sure? But, as a furniture builder, carpenter and a 24/7 wood burner in winter, I am a dyed-in-the-wool wood geek. This week I've been making "little ones out of big ones", splitting my wood for this upcoming heating season, so I've had firewood on the brain lately as well. This got me to thinking about what a BF would find compelling about a stick of wood, and I really think it might not be all that complicated.
First off, we have to acknowledge a Wood Ape is surrounded by this material, from birth to death, but in an unworked form. A piece of split firewood has the qualities of both being familiar, but unique at the same time. As far as we know, I think, they do not have the ability to fashion anything like this on their own, and they recognize it as special for that reason. It may bestow status on a WA that has a piece of it, not only for the intrinsic value, but also possibly as a trophy of a kind. As you noted, seasoned firewood resonates quite nicely when struck against a tree, or another piece of wood. (One theory I have is that many of the reported "wood knock" episodes reported in BFRO reports might only be campers doing this...it is a satisfying feeling/sound, as anyone knows who has connected with a fastball with a H&B ash wood bat )
When I split a large round of oak down to splits for my stove, I often wind up with either a triangular or roughly squared piece of wood from the center, without bark. I refer to these as the "fillets" of the tree. I often will just pick them up and note how they are, well, just plain cool to look at and hold. There is something in the hominid brain (well, in mine at least) that gets a burst of endorphins when you hold a fashioned piece of wood. Imagine this feeling if you had no ability to make something similar on your own. You'd covet it, for sure.
You might want to pay more attention to the types of firewood splits that get pilfered. Size and dimensions, as well as symmetry may matter.