Wood varies in hardness. Although both can be used, there is a major difference in how they burn. Hardwood includes maple, oak, ash, walnut, locust (honey or black), cherry, peach, apple, hickory, and beech while softwood includes conifer, pine, cedar, hemlock, poplar, spruce, and fir. Generally, hardwood will burn for longer periods of time. Hardwood will also create hotter, smoldering coals. Softwood is ideal for short, hot fires. We usually recommend mixed hardwood because it burns longer and cleaner with less creosote buildup in the chimney.