Holy shit my friend John and I made a song with this same lyrical theme called "Oaken". I can't remember which of us came up with the idea originally but he wrote the lyrics and i made the music; but we never finished it because my music blew big time. It was sometime after i did Fear The Unknown. But we should resurrect the lyrics and do it again. The idea i had was a guy would die and be buried with a seed and the seed would use his body as nutrients to grow so the guy would become the tree and you would see a face in the grain of the bark, like an Ent or a Green Man; and that would personify the reincarnation of his body. So it's a physical form of reincarnation. I don't bother with the spiritual reincarnation that some people talk about; i like things to be more literal i guess.
Anyway. I think your music suits the quote you have really well. I think it has the right feeling for a sort of transition of life forms. Yeah, cool stuff.