Keep walking; you'll find a way out eventually.
It's hard to tell the exact point where you have to turn on to the other path (it's not very bright in the lower levels of Edanna, let alone in the tree), but if you go all the way up the tree, turn around, head down, and always click slightly to the right of the path, you'll should be able to find the exit. It helps if you just click everywhere.
Once you've gotten on the path, head down the blue swing vine you see (which is not the same one as on level 5).
I'm down at what you describe as level 1. What do I do now?
Oops - I need to get back up to the big tree. How do I do that?