One of the oldest and largest hardwood trees, the Eastern cottonwood is native to North America, growing throughout the eastern, central, and southwestern United States. It was a valuable resource as a construction material for the American Indians and European settlers who used the hard, but lightweight wood to build barns and houses. Today, cottonwood is used for pulp and sometimes for lightweight furniture. Â An identifying characteristic of the Eastern cottonwood tree is that because its leaves are sail-like shaped with long flat stems, they have a tendency to tremble and flutter from even the slightest breeze. The leaf is very coarsely toothed, the teeth are curved and gland tipped, and the petiole is flat. The leaves are dark green in the summer and turn yellow in the fall.