The Douglas fir, Pseudotsuga menziesii, is a mostly, but not entirely, western species of tree. Though it grows in many places, the most imposing examples are found in Northwest Oregon and Southwest Washington.
In this area, these trees grow nearly as tall as the well-known redwoods, though they’re not nearly as bulky. These firs can tower over 300 feet, and the tallest is only about 20 feet shorter than the tallest redwoods. Most Douglas firs are much shorter, with 40 to 60 feet being a common average.
Looked at from a distance, the tree has a roughly conical shape, with branches at the top much shorter than those at the bottom. These are evergreens, and they often lose needles throughout the year as others grow. The needles are usually less than an inch in length, however they grow new needles almost constantly, so the tree is still green in the middle of winter.
In the United States, the Douglas fir is a quite commonly used Christmas tree, especially in the West where it grows in profusion in Oregon, Washington, California, Idaho, and Montana. It also grows well throughout the northern states and far into Canada.
Young Douglas fir trees have a smooth, whitish-gray bark. It is common for small bubbles to form in the bark, filled with pitch. As the tree matures, the bark splits and becomes rougher. The presence of the resins in the pitch make the tree wonderfully aromatic, and cause it to burn hot and fast. It isn’t a surprise that many people use this fir for firewood. It is especially good for forming a base in which to get hardwood burning.
The trunk of this fir grows generally straight and most often doesn’t branch out as is common in hardwood trees, except for the limbs growing out from the trunk, roughly parallel to the ground. The roots grow deep and spread out to the drip line of the tree. This, and the narrow shape, allows these firs to often grow in dense thickets.
The wood of this tree is white to yellowish in color. The tree rings are usually farther apart than with oak or maple, but often not as far apart as with pine.
The cones aren’t large and prickly, as is common in pines. The bracts of the cones have a look of a squirrel leaping down a hole. This is a major identifier for this tree, as it isn’t common among fir and pine cones.
A Douglas fir is a majestic tree. It can grow to great heights, can withstand bitter cold and moderate heat, smells great, is useful as firewood, and grows well at high altitudes.
Sources:
US forest service
US park service
Oregon Agricultural Extension service
http://www.conifers.org/pi/Pseudotsuga.php