What is a Douglas Fir Tree?

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Pseudotsuga Menziesii

The Douglas fir tree is a coniferous evergreen tree that is part of the pine family (Pinaceae). This is one of those trees where its name can be a bit confusing, because Douglas firs are not actually true fir trees, nor are they part of the fir family (genus abies).

They are technically a pine tree, though their scientific name explains where the misnaming comes from. Pseudo means false in greek, and tsuga is the scientific term for hemlock. Menziesii is the epithet given after Archibald Menzies, who documented the Douglas fir on Vancouver Island in 1791.

Its official name, the Douglas fir, comes from the Scottish botanist, David Douglas, who was the actual first person to document the tree. Though it sometimes also goes by the name of Doug fir, Douglas spruce, Oregon pine, British Columbia pine, Puget Sound pine, coast Douglas fir, false hemlock, red fir, or red pine. It seems as if no one can actually tell what family the Douglas fir actually belongs to!

For the purpose of this article, we will stick with the most common name for the tree; Douglas fir. Just remember, this tree is part of the pine tree family! These large trees have an average life expectancy of between 500 and 1000 years! That makes them a proud member of the old-growth forest.

Though the Douglas fir grows in the Pacific Northwest, we’ve explored 101 Types of Trees from all around the world! Check it Out!

Related: Fraser Fir Tree | Balsam Fir Tree

What do Douglas Fir Trees Look Like?

Root System

Though it can be slightly varying due to their growing location, Douglas fir trees usually come equipped with one primary taproot that grows very deep into the earth and some supporting lateral roots.

The taproot is useful to help with resilience against windthrow, and as a way for the tree to access water reserves that can be found deep in the soil. The lateral roots penetrate the earth at a sharp angle and help provide stability.

Dimensions

Douglas fir trees have very varying sizes. These trees can be anywhere between 20 to 100 meters in height, of course depending on their growing location. Douglas firs found near the coasts of British Columbia, Oregon, and California will have the most impressive growth. Their trunk diameters will usually reach a width of 2-3 meters around.

Growth Pattern

When Douglas firs grow in forests, they will experience their tallest growth and smallest crown. When they grow in a dense forest they will self-prune their lower branches in order to conserve energy, and oftentimes their crown will only start at around 30 meters up the trunk’s length.

When Douglas firs grow in more open spaces with greater sun exposure, they will often be shorter and will have branches that start their growth much lower down on the trunk.

Bark

The bark of a Douglas fir on a young tree will be smooth and a light gray color. Bark on mature trees will have darkened in color and developed deep furrows. These furrows will possess a bright red/brown color, making the tree easily recognizable by the look of its thick bark.

Foliage

The leaves of the Douglas fir are needle-like and are evergreen (meaning that they do not shed seasonally). The needles are flat and between 2 and 4 cm in length. They are soft to the touch and are a bright green color.

Needles are arranging individually on a stem instead of growing in fascicles or clusters. The needles completely encircle a twig, making it look like a bottle brush. This is one of the easiest ways to identify a Douglas fir tree.

What are the Different Types of Douglas Firs?

There are three varieties of Douglas fir trees, and these varietals are all dependent on different growing locations, rather than drastically different physical attributes. The three varieties are as follows:

Coastal Douglas Fir (pseudotsuga menziesii var. menziesii) – this variety of Douglas fir grows on the coasts of Oregon, California, Washington, and British Columbia. They experience the tallest heights of the three varieties.
Rocky Mountain Douglas Fir (pseudotsuga menziesii var. glauca) – this variety of Douglas fir grows farther away from the coast and in more mountainous regions of those states and province. They are the sturdiest, and are usually medium sized.
Mexican Douglas Fir (pseudotsuga menziesii var. lindleyana) – this variety of Douglas fir grows in Mexico close to the border, and these trees are the smallest and most drought tolerant of the three varieties.

How do Douglas Fir Trees Reproduce?

Douglas Fir Cone

Douglas fir trees are monoecious, meaning that they possess both male cones and female cones on the same tree. This does not mean that they engage in self-pollination, as that would lessen genetic diversity in a species, resulting in more vulnerabilities.

Seed cones (ovule producing – female characteristics) are pendulously arranged with persistent scales. The scales are three-pointed bracts, with the top point protruding prominently from the scale. Cones are light brown in color with a papery texture.

Pollen cones (pollen-producing – male characteristics) are erect with similar scales. Cones will dry out at maturity, where pollen will then be released into the air, and brought to the seed cones of another tree through wind pollination (as the seeds are very small and light).

Douglas fir cones are usually pollinated in the spring, they become fully mature by the fall, and seeds will fall throughout the winter and spring. Seeds will germinate in the spring, though sometimes seedlings will remain dormant if conditions aren’t wet or warm enough.

Sexual Maturity

Douglas fir trees are pretty late bloomers, in that they won’t usually start producing cones until they are at least 20 years old. Their crops occur at very irregular intervals, with heavy crops occurring about every 7 years or so.

That being said, only about 1/4 of all Douglas fir trees actually produce seeds. Old-growth firs will produce the vast majority of cones and Douglas fir seedlings.

Where do Douglas Fir Trees Grow?

The Douglas fir forest is reserved for the western side of North America. They occur most popularly in British Columbia, Washington, Oregon, and California. There is an incredible old-growth stand in the Mattole Watershed, and other prosperous stands in the Sierra Nevada and southward to Yosemite Valley.

These trees will grow close to sea level and as high in altitude as 1800 meters. They are fierce competitors on dry sites and all varieties of aspects and slopes.

They are often associated with the following other tree species:

bigleaf maple
California incense cedar
coast redwood
grand fir
Lawson’s cypress
ponderosa pine
tanoak
Sitka spruce
sugar pine
western hemlock
western white pine

Douglas firs have also been naturalized throughout Europe, Argentina, Chile, and are even so prosperous in New Zealand that they are considered as being an invasive species, and are some of the largest trees that can be found there.

What are the Growing Conditions of Douglas Fir Trees?

Soil

Douglas firs can tolerate a great many soil types. They perform very well on dry sites as well as moist sites as long as they are well-drained. They can tolerate both acidic and neutral soil, though grow the absolute best on bare mineral soil.

Sun Exposure

Douglas firs are shade tolerant, though they perform best in full sun which is common for coniferous evergreen trees. Seedlings tend to need full sun in order to germinate, though older trees can tolerate light shade.

What are the Damaging Agents of the Douglas Fir?

Douglas firs are not particularly vulnerable to these pests but do experience defoliation. The wooly conifer aphid (Adelges cooley) is a sap-sucking insect that lives on the underside of needles. They appear a white fluffy spot, which is actually a wax that they excrete. They are damaging in large numbers, and they cause the yellowing of foliage.

Douglas firs also experience defoliation for bark beetles, the Douglas fir beetle, and they are heavily grazed upon by gelechiid moths (chionodes abella) and the tortrix moth (Cydia illutana).

How are Douglas Fir Trees Used?

Wood

Douglas fir wood is one of the best-known and widely-used woods on the planet! It is valued for its strength, hardness, durability, and workability. The wood is lightly colored with a medium texture, straight grain, and it is not porous.

Douglas fir wood takes stain, polish, and paint extremely well, and it is easily workable as well. It is often used for joinery, veneer, and flooring.

Ornamental

Douglas firs make for incredible ornamental trees and are often used as a landscape plant in public parks and gardens. Douglas firs have also been used as commercial Christmas trees since the 1920s! Not to mention, there are tons of old-growth groves that make for amazing scenic viewing.

Forestry

The Douglas fir is a staple tree species in forestry management. They are often planted as plantation trees because of their fast growth and hardwood, making them the perfect tree for softwood timber.

Wildlife

Douglas fir seeds are eaten by the Douglas squirrel, chipmunks, mice, voles, and birds. Old-growth Douglas fir trees are also a very important habitat to some endangered species, like the spotted owl (strix occidentalis) and the red tree vole (arborimus longicaudus).

Ethnobotanics

Native Hawaiians have traditionally used washed-up Douglas fir logs to create double-hulled canoes — vessels which they call wa’a kaulua.

Native American communities have also traditionally used the bark and resin of the Douglas fir tree to create herbal treatments and salves. Douglas fir needles can be made into pine needle tea, which not only has medicinal value but has a pleasant tangy/citrus flavor. It can also be used as a substitute for rosemary!

The winter buds of the Douglas fir tree are also sometimes collected and their essential oils are extracted, which then go into the scent and flavoring of certain kinds of perfumes and brandy.

FAQs

How long do Douglas fir trees last as Christmas trees?

If you’re planning on using Douglas fir Christmas trees, you’ve made a good choice! When cared for properly, Douglas fir needles can actually remain on a chopped tree for up to 5 weeks after it has been uprooted.

What is the difference between a Douglas fir tree and a noble fir tree?

Most folks find it difficult trying to choose between a Douglas fir and a noble fir tree for their Christmas tree. The main difference between the two is that the noble fir tree has more weeping-like branches, but they are quite sturdy, making a great choice for heavier ornaments.

Douglas fir trees have weaker and thinner branches, though the needles are softer. However, the noble fir is much less widely available than the Douglas fir is.

What is the difference between Concolor fir and Douglas fir?

The Concolor fir tree (abies concolor) has the strongest branches out of all the Christmas tree fir varieties. They also have very citrus-like smelling foliage which attracts Christmas tree hunters.

What is the oldest Douglas fir tree?

The oldest known Douglas fir tree is called The Red Creek Fir, and it grows on Vancouver Island. It is 73.8 meters tall with a trunk diameter of 9.8 meters, and it is said to be over 1000 years old.

Why is the Douglas fir Oregon’s state tree?

The Douglas fir was a prominent feature in the economic development of the state of Oregon, as forestry is such an important industry there. Oregon is the 8th state to have elected the Douglas fir as its state tree!

How long do Douglas fir trees live?

Most Douglas fir trees have a life expectancy of between 500 and 1000 years, though this is all dependent on their growing ranges, and whether or not they have been planted for lumber purposes.

How fast do Douglas fir trees grow?

Douglas fir trees are fast-growing trees, and will often grow up to 24 inches per year.

How tall do Douglas fir trees get?

What is the trunk diameter of a Douglas fir?

Depending on its height, a Douglas fir will have a trunk diameter of between 1 and 3 meters.

What is the difference between a Fraser fir tree and a Douglas fir tree?

Fraser fir trees have a different growth pattern than the Douglas fir tree. Fraser firs have a thinner and more narrow crown, with upward ascending branches. They also have a much stronger smell of pine than the Douglas fir.

Do Douglas fir trees shed?

Douglas fir trees are coniferous evergreens, meaning that they possess cones and needles instead of flowers and leaves, and their foliage does not shed seasonally. A Douglas fir will shed its needles (not all at once) after around 5 years of the needle existing on a tree. Otherwise, the needles will only shed due to a drastic environmental change.

How do you prune a Douglas fir tree?

The best time of a year to prune a Douglas fir tree is in its dormant stage, which is in the springtime.

Is Douglas fir as good as cedar?

Firwood resists warping and splitting over time, whereas cedar does not. Cedarwood doesn’t rot as quickly as fir wood does, but fir wood doesn’t weaken or discolor are screws and nails like cedarwood does.

What animals eat Douglas fir?

The Douglas squirrel, as well as chipmunks, voles, and birds all, eat the seeds of Douglas fir trees. Many moth and butterfly species also browse on foliage.

How far do Douglas fir roots spread?

Is Douglas fir better than pine trees?

Firwood has very little soft grain, whereas pine has a very soft grain. However, pine wood is much weaker and more prone to warping and splitting, whereas fir wood does not have that same issue.

What is a Canaan fir tree?

The Canaan fir tree is a southeastern North American species of fir tree. Their growing range occurs from Quebec towards West Virginia. This species in a natural hybrid between the balsam fir tree and the Fraser fir tree.