 In 1648, a company was formed in Sweden called "Norrländska Tjärkompaniet" (The Wood Tar Company of North Sweden), and was given exclusive export rights for pine tar by the King of Sweden.Coniferous tree sap is a viscous liquid, that contains terpene, a volatile hydrocarbon.Over time the evaporation of the terpene changes the state of the sap; it slowly gets thicker until it hardens into resin.