Birches bend and shed their bark, but should they bend for me?

[H[a/o]llowheart]

I really liked the rhythm of the poem. Especially the first paragraph, with the consonance in line one and the assonance in line three. However, the flow gets a bit iffy later on. You switch up the rhyme scheme from ABAB to ABAC, then to ABCB, and finally ABACC. The inconsistency breaks up the sing-song aspect of the poem. As for some nitpicks: I think that "with might and careful adaptation" and "through hesitant amalgamation" should be right next to each other. They're both prepositional phrases (someone correct me if I'm wrong on that, my grammar sucks >_>) and sound a bit awkward one after another when they're not in the same chunk. Also, describing the trees as using "might and careful adaptation" personifies them as being calculating and focused, while "hesitant" has a weaker, insecure connotation. You could consider changing that. 

All that being said, I love the last two lines! The play on the repetition of the word "bend" as well as encapsulating the idea of nature > artifice, or at least the battle between the two, brings the poem home with a nice punch.