Deck plywood is a type of plywood that is specifically designed for use in outdoor decking applications. It is made from layers of thin wood veneer that are glued together in alternating directions to provide strength and stability.Deck plywood is typically made from high-quality, rot-resistant wood species such as Douglas fir, cedar, or redwood. The wood veneers are treated with preservatives to protect against rot, insects, and other forms of degradation caused by exposure to the elements.