Woodward’s Don Wirth, archeologist and savanna-restoration guru, explains the traits of the white oak tree at the Iowa Arboretum Saturday. Iowa and its oaks was the topic of a lecture and short hike at the tree reserve near Luther, and the 20 people who braved the cooler temperatures and soggy ground learned about many of the state’s dozen native oak species and of efforts to restore the prairie savannas in which they once flourished. Nan Bonfils, director of the Arboretum’s educational programming, introduced Wirth and outlined the center’s upcoming fall lectures and activities. "We’re glad to have our educational programs up and running," said Mark Schneider, executive director of the Arboretum. "My goal is to continue to develop the Iowa Arboretum into a great resource for the surrounding communities." The Saturday, Oct. 12 talk and walk will feature University of Iowa Arborist Andy Dahl discussing the colors of fall leaves. Visitors will learn why trees change color and what gardeners can do to enhance and enrich the natural fall colors of the trees. The informal classes meet from 9-11 a.m. in the Arboretum’s Cafferty Building. Call 515-795-3216 for more information.