Native Cottonwood trees have always been considered by some to be sort of a junk tree.  They grew without consent and grew fast.  They dropped copious amounts of leaves and dropped dead branches without warning.  Someone once said that "a weed is a plant for which you have found no use."  The trees that were found in wet areas of the Western Plains at lower elevations were mostly Cottonwood or Aspen.  The wood is soft and easy to craft.  The dried wood burns well and the inner bark provides winter fodder for horses who cannot find or reach grass. Their spreading branches provide shade when the sun blisters every living thing.  Plus, when you see a Cottonwood grove, you can suspect water is near the surface.