Coloradans pack their tents and head to the hills during the summer, but a University of Colorado historian says camping isn’t just about recreation. Protesters sometimes use it as a way to stake out territory and force change, and those without permanent housing sometimes use makeshift camps for shelter. Phoebe Young is an associate professor of history at CU Boulder and the author of “Camping Grounds, Public Nature in American Life from the Civil War to the Occupy Movement.”