The term 'Cottonwood Tree' refers to two species of trees in the Populus genus, the Eastern Cottonwood (Populus deltoides) and the Fremont Cottonwood (Populus fremontii). The Eastern Cottonwood is also known as the ALAMO, and is native to the eastern United States and Canada. The Fremont Cottonwood is native to the southwestern United States and northern Mexico. Both species are fast-growing, deciduous trees that can reach heights of up to 100 feet. They are often found near rivers and streams, and are valued for their shade and timber.