My concept proposes to use wood chips or saw dust to make the filaments of wooden 3D printer.
Models in wood are constructed from a brown, very fine, granular powder made from wood chips. The surface has a sandy, granular look, and is slightly porous.
Wood is perfect for complex models, as it allows for interlocking and moving parts.
It is already possible to make 3D printed models of wood in small sizes, I think it can be scaled up to 3D print big furnitures using wood dust or wood chips hence we can reuse the wood almost completely. I think FPIntell should research in this field as already 3D printing is a widespread technology now.