While the tree trunk room on the island of Haida Gwaii isn't a fully functional home, it's a perfect example of just how sustainable spaces can be. Artist and fisherman Noel Wotten of Sitka Studio built the tiny room in the tree trunk to be used as a community space and place to play music.

After about two years of carving out the tree, Wotten was left with a space that resembles a whimsical home in a fairy tale. The furniture inside and art on the walls is made from the tree as well, ensuring that as little of the trunk went unused as possible.

Windows and a front door let in ample natural light while the tree is hooked up to electricity for additional lighting and heat.The room is well constructed enough to accommodate funny photos and notes left by guests of the hut without falling subject to the elements. The space is known for its excellent acoustics, so much so that the room is semi-regularly visited by known musicians like Eric Clapton.  

Read more about the super sustainable space on TreeHugger