Maybe this is closer to spirituality than science, but I’ve been reading Eckhart Tolle and he explains in a few of his books that the whole idea of “I” or “My self” is an illusion that’s created by the ego. This is also the message from a lot of Eastern philosophy.

I would hazard to guess that individual consciousness doesn’t actually exist, so of course a tree can’t be individually conscious because neither can a human. We (both the tree and the human) are part of a collective “consciousness” that is life itself.