In the West, aspen are one of the predominant trees coloring the landscape in the fall. Along the Green River in Wyoming, narrow leaf cottonwoods (Populus angustifolia) provide much of the fall colors. This species of tree provides excellent habitat for many species of migratory birds. During migration periods, its tendency to have shrubby branches starting at the base of the tree with larger diameter branches above provide abundant leaf surface that attract many insects. This feeds warblers and numerous other insectivorous birds that have high energy demands during migration. Bald eagles, Swainson's and red tailed hawks, great horned owls, yellow warblers, and many other species nest in its protective branches.

The life history of narrow leaf cottonwood is an interesting one. It establishes from seed on recently deposited gravel and sandbars along the Green River. The young seedlings must "chase" the rapidly receding water table of summer and most don't make it. Ice floes in the spring thaw also bulldoze down the river each year and often scrape off the newly establishing stems. The young stems are also frequently eaten by moose, deer, beavers, and other wildlife.

For the ones that make it to maturity, they have the ability to send up new trees from established roots. Research on this species has shown that as many as 70% of the existing trees are connected through their roots to another mature tree. Like aspen, once established, they may reproduce clonally under the right conditons. Over the generations this can help to perpetuate the stands. Research on and above Seedskadee NWR has shown that many of our cottonwoods are 150 years old with some up to 300 years old. Who knows when the original parent trees may have established?