It’s difficult to see the forest for the trees, especially when most of those trees are conifers. After all, conifers all tend to look the same, especially from a distance. People don’t come from all over to gaze in awe at the evergreen fall colors. It is the aspen trees in our valley that get all of the credit with their bright yellow and orange hues. But among the depths of the common evergreens, lies one majestic conifer that is often overlooked – the Douglas-fir.
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Despite the name, the Douglas-fir, Pseudotsuga menziesii, is not a true fir (true firs belong to the genus Abies). The Douglas-fir does however, share many characteristics of a fir, including flat needles, gray-ish bark, and resin blisters. Additionally, the Douglas-fir tree shares similar traits with spruces, pines, and hemlocks, making the Douglas-fir difficult to categorize. In fact, our poor Douglas-fir has had its scientific name changed 21 times until arborists decided to give the Douglas-fir it’s very own genus, Pseudotsuga, meaning “false hemlock.” The common name of Douglas-fir stuck around in honor of the Scottish botanist, David Douglas, who first recorded this majestic tree. There are two varieties of Douglas-fir trees, the coastal Douglas-fir and the Rocky Mountain Douglas-fir that we have in Colorado.
The cones are one of the most notable characteristics unique to the Douglas-fir tree. True fir cones grow upright, whereas Douglas-fir cones droop down and hang below the branch. Perhaps the most distinct part of the Douglas-fir cone are its three-point bracts, or modified scales, that extend from the cone scales. These bracts are hard to miss once you see them and are a dead giveaway that you are looking at a Douglas-fir tree.
Here in Colorado, it is not uncommon for Douglas-fir trees to reach over 100 feet in height with a 2-3 feet diameter trunk, and to live between 300 and 500 years. Although this may seem impressive, the faster growing coastal Douglas-fir trees are the second largest trees in North America. The largest reported Douglas-fir tree comes in at an astounding 328 feet tall and has a diameter of 14.3 feet! The oldest living Douglas-fir is between 1300 and 1400 years old.
Douglas-fir trees are not just impressive for their size and longevity, but they have a wide variety of uses as well. First of all, the Douglas-fir is a prized timber species for its particularly strong wood. Many different animals also make use of the Douglas-fir, either as shelter or a food source. Mule deer especially love to graze upon its needles in winter when other food sources are scarce. Bears will even scrape away the bark to feast on the sap underneath. But perhaps the most common use of the Douglas-fir is one that many of us can relate to: Christmas trees! Although by now all of our holiday trees have been ceremonially burned or tossed into a dumpster, next season, consider the Douglas-fir for your perfect Christmas tree. The Douglas-fir is a fragrant tree with friendly needles and perfect branches for hanging ornaments. It is considered the prized tree to harvest for the holidays, but be sure to purchase a permit to harvest a Christmas tree in our Colorado national forests.
Next time you are out playing in Colorado’s forests, keep an eye out for a towering Douglas-fir. It is a sight not to be missed. And take a moment to appreciate its magnificence and importance to so many forest species.
Marshall Kohls is a Naturalist with Walking Mountains Science Center. He has spent many summers working forestry. Although his favorite tree, the white pine, is absent from Colorado, the Douglas-fir takes a close second.