Jeff Ennis and his four sons built this birchbark canoe (16' x 36") in the summer of 2004 in Lac St. Marie, Canada. They used birch bark, green cedar, and spruce root in the construction. The green wood can be easily split into almost paper-thin sheets for making the floorboards. He adds, "The unique thing about the birchbark canoe is that it contains no nails. The shape of the boat is maintained by counterbalancing forces...the pressure of the gunwale to push in, against the pressure of the ribs to push out. Typically the entire boat is made out of natural materials.