Poplar.
Under this name is included such woods as American whitewood, cotton wood, bass wood, etc. The wood sold under one or other of these names is generally very soft and brittle, and although of a light nature, weighing about 30 lbs. per cubic foot and less, it is of very little utility for the work under discussion. It has been used for minor parts such as rib webs, and fairings to tubular struts.