Iowa’s selection of a state tree has left itself open to interpretation. Legislators chose the oak tree as one of the state symbols, declining to specify which type of oak. In lists of the 50 state trees, a specific oak type is sometmes listed as the state tree of Iowa, but such designations are erroneous. In Washington, D.C., where the United States National Arboretum cares for the National Grove of State Trees, which contains trees that represent each of the 50 states, a burr oak represents Iowa.
It can take up to half a century for the state tree of Iowa to produce a decent crop of seeds or acorns. The production varies from year to year, with some years providing a bumper crop and others producing fewer. In a good year of acorn production, called a mast year, an established oak tree can produce as many as 50,000 acorns. Before the oak sheds its leaves in autumn, the tree will drop its acorns and they will begin to sprout quickly and grow new oak trees if they can avoid environmental damage from frost or fire, and are not eaten by animals.
The state tree of Iowa is often struck by lightning, with one theory stating it is because it possesses low electrical resistance. Another theory attributes the many lightning strikes to the fact an oak is among the tallest beings in many settings. Whatever the cause, lightning bolts were associated with certain Roman and Greek gods, who became linked to the oak’s symbolism. Monarchs in ancient times, thought to be deities, wore oak leaves as their crowns to reinforce their image as gods. Roman warriors who were victorious were given oak leaves, and today some modern warriors serving in the military wear oak leaf icons on their uniforms.
More than 400 different species of the oak tree grow around the world. The burr oak, chosen by the National Arboretum to represent the state tree of Iowa, is found throughout the state. Also known as the mossycup oak, it holds up well in times of drought but does not like to be transplanted once it is established. It has long limbs, and under the right conditions it can live a long time. A variety of animals use the oak for protection and for food. The oak’s strong wood is favored for flooring and furniture. It is also a popular tree in the landscape.