[She's a little puzzled by his reaction to the mention of magic. As far as she knows a lot of things here have to do with magic.]

I dunno, it seems like it could be magic to me. Whatever kind the Tree uses to do all the other things that it does. But I don't know much about alchemy... I wouldn't want to mess around with it trying to make trees, though.

[She frowns at the tree. She is still skeptical of your skepticism, Fullmetal.]

Maybe. I'm still not sure about it, but as long as it doesn't... change.

[Was totally going to say 'as long as it doesn't try anything' but... yeah.]