Some natural building forms that have served humanity well for millennia still have a place in the contemporary green building movement, but one that is limited by scarcity. Wood and stone can play a part in sustainable building, but both are building materials that cannot be used indiscriminately today. Over the centuries, all northern forested regions developed timber framing traditions. They were appropriate technologies that married plentiful local materials with deep levels of craft. In many cases, the lumber used came from trees taken from the building site. Infill was usually some mixture of straw and clay, and roofs were comprised of thatch or stonematerials that often constituted the farms waste products. Whether they were simple houses, or magnificent Shinto temples or Scandinavian stave cathedrals, they proved eminently durable and beautiful (Chappell, 2002). Today, as discussed in chapter III, wood is an endangered renewable resource. In particular, large dimension timbers are relatively scarce and often sourced from endangered old growth forests. The green building movement prioritizes the use of smaller dimensional lumber and the fabrication of trusses and beams from waste wood and small stock. In many cases, the concern is how wood is being used. A conventional platform-frame building can use up to eight times the wood that a post-and-beam