"Among the pale cottonwoods"
Creative Commons AttributionCottonwoods (Vaughn, New Mexico) - Credit: John Phelan

Trees had to survive prairie fires in order to survive on the Great Plains. Cottonwoods did this by typically growing on the edges of rivers and streams and by developing a thick, corky bark upon maturity.

This makes it a significant tree in the formation of modern America, since the sight of cottonwoods meant water, and often survival, for the European pioneers heading West across the great desert plains.