This entry in the Instructables Green Design Contest is the ultimate TreeHugger eco-lounger; just take a pile of birch and screw it together into what looks about as comfortable as a bed of nails. But it is very green, sequestering carbon dioxide for the life of the chair, which is probably about a week.
A reader complained that TreeHugger should not be contributing to deforestation by showing such a project. I noted that birch has a very short life, can be sustainably harvested, and that this might have been made from fallen wood.
For all my making fun, it is probably pretty solid; there are steel brackets underneath, holding the logs in place. More: Build your own log lounge chair for $30