For fuel to heat food, travelers would collect cedar wood, cottonwood, or willow wood, when available, and sometimes dry prairie grass. More frequently, however, travelers relied on "buffalo chips"—dried bison dung—to fuel fires. Buffalo chips resembled rotten wood and would make clear and hot fires. Chips burned quickly, however, and it took up to three bushels of chips to heat a single meal. Collecting buffalo chips was a common task for children and was one chore that even very young children could carry out. As a result, "memoirs written by those who were very young when they made the journey west invariably refer to this aspect of life on the trail."