A piece of lumber is a type of wood that has been cut into a specific shape and size for use in construction or other projects. The three most common types of lumber are logs, boards, and planks. Logs are cylindrical pieces of wood that have been cut from a tree trunk. Boards are rectangular pieces of wood that have been cut from a tree trunk or branch. Planks are long, thin pieces of wood that have been cut from a tree trunk or branch.