The American Elm (Ulmus Americana L.) was named as Nebraska's first state tree on Feb. 15, 1937, when a resolution introduced by Sen. Alois Slepika of Wilber was passed. It was chosen because it was "known throughout Nebraska for its beauty, and because of its historical background, it being the tree under which George Washington sat while signing a treaty."
The 1972 Legislature named the cottonwood (Populus deltoides marsh) as the state tree. The bill, introduced by Sen. Calvin Carsten of Avoca, originally called for the green ash to be the state tree, but was amended in favor of the cottonwood. The cottonwood was chosen because many Nebraska elm trees had been killed by Dutch elm disease and because the cottonwood often is associated with pioneer Nebraska. Several famous early landmarks were cottonwood trees and their shoots were often collected by settlers who planted them on their claims.
Today, the cottonwood grows throughout the state. The green ash was designated as the 1972 Arbor Day Centennial Tree.