@Girlie1Bomba I get where ya comin' from! :D
Honestly, I had imagined the Tangle as a whole to be what you describe as The Green Corridor: full of nature and magic, encroaching upon anything broken or destroyed. There really isn't anyone within the Tangle that is destroying nature or would even think of cutting down trees. Everyone lives within the same magical space as Mama Rayn, and in harmony with nature.
What's OUTSIDE the Tangle, though .... well, that's why there's a guardian at the door. That's why the Tangle is an impossible maze: to keep visitors from being able to do much damage.
Perhaps Mama Rayn remembers a time when the Tangle wasn't a maze at all, but a wide lush landscape that stretched on forever. Since then it had shrunk ... and shrunk. And she felt every crack of an axe against a tree. Fairies vanished, lights dimmed. The other unicorns all disappeared. Out of desperation the rocks erected the walls of the maze, entwined them, kept the destructive ones out and hid the magic inside -- and so the Tangle IS Mama Rayn's Green Corridor, the only one left.
Perhaps there are a few relics of that age hidden in the corners of the maze -- strange old buildings and scarred earth, all since reclaimed by green and magic -- but otherwise most have forgotten that old time.
Of course, now that we've established that the Door exists, it's only right that it should open -- and outside it is the 'mortal domain.'