Firewood refers to wood that is cut and split for use as fuel, typically for heating or cooking. It can be made from various types of trees such as oak, maple, pine, or birch, among others. The term also encompasses the process of gathering firewood, which involves finding suitable wood in the forest and cutting it down with an axe before splitting it into smaller pieces for easier burning. Firewood is a renewable energy source that has been used by humans for thousands of years to keep warm during cold weather or to cook their food.