Jamie, It seems most of the older dugouts down here were made from pine. A fire was built around the tree till it fell, thus , not having to chop a big tree down with stone tools. And then it was worked with hot coals and stone adze's. The heat also hardened and helped waterproof it sealing the resin. It makes more sense to me the stone tools were used to scrape and chop the burned, softened wood than chopping hard pine or cypress. And after that, it would have took just elbow grease to take sand and water and "wet sand"the soot and smooth the inside.