[Kin-strife]

Some interesting points Sharkù. The thought of animated nature could be seen as the influence behind myth in general. A lot of mythology stems from ideas inspired by the natural world. Before the days of hard scientific fact explanations of everyday and not so everyday natural events were a whole lot more imaginative. For example, as you mention, avalanches being perceived as giants throwing about stones in Mirkwood (did this exist in many other mytholgies, forgive my ignorance). It can be seen as a product of the superstitious (and perhaps paranoid) mind before the safe certainty of scientific belief. Before the general understanding of the natural world anything was possible.
There isn't much I can add to your post but there is something I've always noted about Tolkiens Myth which I think I could mention here. I've always though the myth bears the mark of being written in a scientific age. It can't be said that anything can happen in Tolkiens myth in the same way as it can be said for other, more ancient, myths. The boundaries of science are eliminated but brand new ones are set in its place. You are very rarely left wondering where something came from, the answer is given to you. The origins of most everything, with the exception of Eru, are given in the books. Or at least the means of deducing the origins are given. I imagine that this attention to detail comes from the scientific time the books were written in. Perhaps it was Tolkiens realisation of this fact that caused him to include Tom Bombadil, the enigma. To salvage what he could of that feeling of bounderlessness from the myths that inspired him. I think it is this "substituted science" that is the attraction to a lot of readers. I for one like the utterly fantastic, yet somehow strangely believable world Tolkien provided. A science like depth of explanation without the banality. It doesn't stretch science by creating some extraterrestrial world which could exist but I could never visit. It's our world through a sideways perspective. You can go to a nearby forest on a windy day and imagine nature being animated around you, the trees clawing at you in defence in case you should try to chop them down. I think animated nature is essential to the enjoyment of fantasy; a way to escape from scientific law. If this is all be a bit off topic I aplogise.