After an hour of hiking up and down mountains and canyons at 7000 feet, Mr. Nester led the group to a clearing in the dense pine woods. "Shelter is one of, whether you are roasting in the desert or freezing in sub-zero degrees," he said, instructing his students on how to make a primitive shelter called a Wickiup. We then littered the floor inside with pine needles. "You have to have something between you and the ground," Mr.Nester said. "Otherwise the ground will suck the 98.6 degrees of temperature right out of your body.