R = belongs to red oak group—acorns mature over two seasons & leaves typically have pointed lobes. W = belongs to white oak group— acorns mature in one season & leaves typically have rounded lobes.
Estimated size range is height x spread for trees growing in eastern Nebraska.
A few places to see oaks: Indian Cave State Park; Krumme Arboretum in Falls City; Peru State College; Fontenelle Nature Center in Bellevue; Elmwood Park in Omaha; Wayne Park in Waverly; University of Nebraska Lincoln; Lincoln Regional Center Arboretum; Ehman Park in Gothenburg; Highland Park in Hastings; UNL Extension Center & Cody Park in North Platte; and UNL Extension Center in Scottsbluff