This was my assumption as well, especially given that both doors have the usual yellow outlines. The sticking point for most of my friends was some weirdness in the art that looked like one door had a small staircase or other progression upward in front of it. Enough of them agreed on the visual interpretation that I figured it worth asking.
The artwork on the tile can give you either answer.
The main part of the tree is going past the top of the tile, there are also boards nailed to it, like a ladder or steps. That is the path to the second floor.
The door on the left side of the tile is closer to the ground. It would appear that is the door that you're going through when you find the room. You walk down the stairs until you are at the base of the tree, then climb up the tree to find the bridge to the door on the second floor.
For example, you flip and play the Tree House tile, you place the plant token on an upper open door(that door is now blocked) and now you can use that as a path from the the upper room to the Tree House.
The way I interpret it is you have the door that is on the edge of the tile, that is what you connect to the door you used to discover it. The small door is inset quite a bit. It is not on the edge of the tile. We figure that is the door to the room you put the plant token on, like you are walking on a branch to get to that room. However, I can see how other are interpreting it differently.
There is an image in the gallery.
Last edited Thu Nov 3, 2016 6:37 pm (Total Number of Edits: 2)