Douglas fir

The Douglas fir (Pseudotsuga menziesii) is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three varieties: coast Douglas-fir (P. menziesii var. menziesii), Rocky Mountain Douglas-fir (P. menziesii var. glauca) and Mexican Douglas-fir (P. menziesii var. lindleyana). Despite its common names, it is not a true fir (genus Abies), spruce (genus Picea), or pine (genus Pinus). It is also not a hemlock; the genus name Pseudotsuga means "false hemlock". Douglas-firs are medium-size to extremely large evergreen trees, tall (although only Pseudotsuga menziesii var. menziesii, common name coast Douglas-firs, reach heights near 100 m) and commonly reach in diameter, although trees with diameters of almost exist. The largest coast Douglas-firs regularly live over 500 years, with the oldest specimens living for over 1,300 years. Rocky Mountain Douglas-firs, found further to the east, are less long-lived, usually not exceeding 400 years in age. There are records of former coast Douglas-firs exceeding in height, which if alive today would make it the tallest tree species on Earth. Some particular specimens that exceeded 400 feet tall were the Lynn Valley Tree and the Nooksack Giant. The leaves are flat, soft, linear needles long, generally resembling those of the firs, occurring singly rather than in fascicles; they completely encircle the branches, which can be useful in recognizing the species. As the trees grow taller in denser forest, they lose their lower branches, such that the foliage may start as high as off the ground. Douglas-firs in environments with more light may have branches much closer to the ground. The bark on young trees is thin, smooth, grey, and contains numerous resin blisters. On mature trees, usually exceeding 80 years, it is very thick and corky, growing up to thick with distinctive, deep vertical fissures caused by growth.