I like heartwood
and @hloo im trying really hard to think of something that starts with Y in its name (like Yew tree) or the technical term for when a tree trunk splits into that Y shape. not having much luck, thought you might find it amusing tho.
oh and I would have liked your post because it is a good idea, I just hate the word bloom, its like some people hate the word moist. - im cool with moist, hate the word bloom.