Montana schoolchildren played a significant role in selecting several state symbols. The state tree, the ponderosa pine, was selected by Montana schoolchildren as the preferred state tree by an overwhelming majority in a referendum held in 1908. However, the legislature did not designate a state tree until 1949, when the Montana Federation of Garden Clubs, with the support of the state forester, lobbied for formal recognition. Schoolchildren also chose the western meadowlark as the state bird, in a 1930 vote, and the legislature acted to endorse this decision in 1931. Similarly, the secretary of state sponsored a children's vote in 1981 to choose a state animal, and after 74 animals were nominated, the grizzly bear won over the elk by a 2–1 margin. The students of Livingston started a statewide school petition drive plus lobbied the governor and the state legislature to name the Maiasaura as the state fossil in 1985.

What year was the state tree selected?