I love Kasja's description of two of the trees as lovers.
"Oh, how long I've waited for such a mate!" Lines like this don't really do it for me. They're rhetoric--they feel like something out of a Shakespeare soliloquy, and not a thought process. Even an alien process.
There's slippage here between tenses at times. I don't think you have anything that's necessarily grammatically incorrect, if we;re going strictly by the book, but there are a couple places that are awkward. The first line, "He is magnificent", led me to believe that the whole scene would be in present tense, which it wasn't. Then, after a few paragraphs in past tense, you'll have this: "Though I’ve seen no visions of his future, or heard his name on the wind, I know that his deeds will be great. Through him, my oath will be fulfilled." Again, though I think the way you're weaving in and out of these tenses makes sense from a technical perspective, it still reads awkwardly to me.
Using single-paragraph sentences for effect is fine, and you do it well for the most part, but in this section you have a lot of single-line paragraphs, often quite close together. Do it too often and they start to lose their effect.
Not much else to add that hasn't already been said.