Description from Wikipedia

Douglas-fir is the English name applied in common to evergreen coniferous trees of the genus Pseudotsuga (pronounced /ˌsjuːdoʊˈtsuːɡə/) in the family Pinaceae. There are five species, two in western North America, one in Mexico, and two in eastern Asia. 19th Century botanists had problems in classifying Douglas-firs due to the species' similarity to various other conifers better known at the time; they have at times been classified in Pinus, Picea, Abies, Tsuga, and even Sequoia. Because...