Douglas-firs are pyramid-shaped evergreen trees with needles that attach directly to the twigs. The needles are spirally arranged but can appear flattened in 2 rows due to twisting at the base of each needle.
Douglas-firs are called firs because like firs they have a series of needles that are separately attached to the twigs as contrasted with pines and larches which have needles in bundles (fascicles) or spurs. Pointed red buds distinguish Douglas-firs from true firs, such as grand-fir (Abies grandis) and subalpine fir (Abies lasiocarpa). True firs have sticky rounded green to whitish buds. True firs also have more stiff rounded needles (with a tiny notch at the tip), and cones which are erect and born on the upper sides of branches. The most distinctive feature of Douglas-firs are the "mouse-tail", or exerted bracts on the cone scales, which extend outside of scales and have long narrow point (the tail).
Did You Know?
Douglas-fir is the one of the most valuable lumber trees in the world. The wood is used as poles, beams, in bridges, as railroad ties, structural timber, in plywood, and to make furniture. It is found in many homes every December as a popular Christmas tree. Native Americans used the resin as an antiseptic in the treatment of burns, scrapes, and rashes. European explorers often placed young shoots in their boots to prevent athlete's foot and nail fungus. The tallest Douglas-fir on recorded is 100 meters (330 feet) high! This long lived species can exceed 1,000 years of age.
Small, crowded, flat, straight evergreen needles 0.8 to 1.3 in (2 to 3 cm) long, with pointed tips. The needles are spirally arranged, but can appear flattened in 2 rows due to twisting at the base of each needle. The needles are flexible and soft to touch, dark yellowish-green to blue-green in color and aromatic when crushed.
As a conifer, Douglas-fir does not have true flowers. It produces pollen (male) and seed (female) cones on trees at least 12 to 15 years old. Pollen cones are yellow to deep red, are located at branch tips and are about 1 in (2.5 cm) long.
Seed cones are approximately 2 to 4 in (5 to 10 cm) long, oval in shape, with semi woody scales, and are green to deep red in color. They occur near the tips of the branches. A distinctive feature is the 3-pronged bract that extends beyond the scales, sometimes referred to as “the mouse tail”.
On young trees, the bark is gray or ashy-brown and thin and smooth with distinctive resin blisters. As the tree matures, the color becomes more grayish-brown with deep and irregular ridges and fissures and develops distinctive thick bark, which can be many inches thick in older trees.
Grows best in well-drained, deep, moist soils, but can also exist in dry soils. Often in pure conifer forests or in transition zones within the forest and found from dry grassy valleys to timberline.
Blooms (pollen disperses) in mid-spring (March to April in southern range, May to June in Montana or at higher elevations). Dispersal generally occurs between mid-August and late September depending on elevation and latitude.
Distribution in the US