The structure was sustainably built with all the materials either being "found or made in the woods." The treehouse doesn't actually touch the trees near it either, allowing "rainwater to run down the stems and wildlife to travel up and down in the normal way, hence maintaining the delicate ecosystem of the oak tree."
It maintains the appearance of a treehouse without being built into the tree. "We don't stress the trees by imposing heavy loads on them or by fixing bolts into them. We believe that the tree has grown in response to its environment and as such should be left well alone."
The treehouse rents for around $400 a night and, as you might expect, reservations are getting hard to come by. But if you're finding the treehouse irresistible, you can book a stay here.