Douglas-fir is a common evergreen tree here in Colorado. Sporting 1-inch needles, extremely thick and furrowed bark, and distinctive cones, mature trees can reach over 100 feet in height and are typically found at elevations between 6,000 and 9,500 feet.
Despite its name, Douglas-fir isn’t a fir tree at all. While it shares many of the same characteristics as firs, it also has traits that resemble spruce, pine, and hemlock, making it very difficult to categorize. For many years, scientists couldn’t agree on how to classify it. Was it a spruce? A pine? Something else entirely? Eventually, they gave it its own genus, Pseudotsuga, which means “false hemlock”. The tree is named after David Douglas, a botanist, and explorer who was one of the first to collect specimens of the tree back in the early 1800s.
There are two varieties of Douglas-fir – the coastal Douglas-fir and the Rocky Mountain Douglas-fir (Pseudotsuga menziesii ‘Glauca’) that’s found here in Colorado.
Douglas-firs are large trees, commonly reaching over 100 feet tall and 2 to 3 feet in diameter in our area. However, they’ve been known to grow much bigger, with some Rocky Mountain Douglas-firs growing to nearly 200 feet and 5 feet in diameter. It’s not that surprising when you consider that they often live for 300 to 500 years!
The Douglas-fir prefers moist, shady areas (such as north-facing slopes) and sheltered areas, although it’s a versatile tree that can also be found in open, rocky slopes and full sun.
From a distance, a Douglas-fir may seem similar to the other conifers around it. But once you get up close you’ll notice a few distinctive characteristics that set it apart.
The most unusual feature of a Douglas-fir is the cones. They hang below the branches (whereas cones stand upright on fir tree branches) and have three-point bracts that stick out between the scales. This is unique to Douglas-fir and an easy way to identify the tree. You’ll often find the cones scattered on the ground around the tree.
Mature trees have red-brown, heavily ridged bark and often have several lichen species growing on the lower part of the tree.
Douglas-fir’s soft needles are short (about 1 inch long), flat and a lovely green color at maturity (they’re a lighter blue-green or green when they first emerge). If you crush the needles, you’ll notice a camphor-like smell.
While Douglas-fir is an excellent source of timber, and also provides food and shelter for many wild animals, it’s perhaps best known as the quintessential Christmas tree. When young, the tree has a nice conical shape, the soft needles are kid-friendly when hanging ornaments, and the branches are strong enough to hold your prized decorations. Just remember to get a permit if you plan to harvest one in our Colorado national forests for your Christmas display.