Wood preservers are professionals who use a variety of methods to protect wood from decay and damage. Two common methods used by wood preservers are creosote and pinetar. Creosote is a dark-colored, oily liquid that is derived from the distillation of coal tar and is used to protect wood from rot and insects. Pinetar is a sticky, resinous substance made from the sap of certain pine trees and is used to protect wood from water damage. Both creosote and pinetar are effective in preserving wood and extending its life.