Plywood is engineered wood made by gluing several thin sheets of wood together with wood grains running alternately along the sheet and across it. Plywood you can say is a substitute to natural wood. Plywood is used in areas where actual wood or natural wood cannot be used entirely in given space. Another reason for using plywood instead of natural wood or plain wood is its resistance to cracking, shrinkage and stability.Plywood is manufactured from softwood, hardwood, or both. The hardwoods used are ash, maple, oak, and mahogany.Douglas fir is the most popular softwood for making plywood, although pine, redwood, and cedar are common. Composite plywood can also be engineered with a core of solid timber pieces or particleboard, with a wood veneer for the face and back. Composite plywood is preferable when thick sheets are required.