Tucson treehouse ~ cool & green

So our temperatures have hit 100 degrees already and it isn't even June - ah, Tucson! I spotted this wonderful treehouse tucked within a massive old growth tree. Looks like it would be pretty cool and shady in there, doesn't it? It has a set of regular stairs (not rungs nailed to the tree) so I bet adults enjoy this retreat, too. Margarita, anyone?