Decorative mouldings have been made of various materials such as wood, stone, plastics, and plaster. MDF moulding is dense, flat, stiff, has no knots and is easily machined. Because it is made up of fine particles it does not have an easily recognizable surface grain, so it's often the best choice for transitions between surfaces. Withers Lumber provides a wide variety of molding made from hemlock, oak, poplar, pine, mahogany, and more.