This is a blog about the native conifers of the Pacific Northwest. It is a companion to the Northwest Conifers site. The blog will focus on timely and interesting details about our conifers, their connections to the rest of the environment, and our connection to them.

Monday, January 18, 2016

Focus on Firs

Grand Fir
Firs (scientific name, Abies) are widespread throughout mountainous regions of the Northern Hemisphere. The genus includes over 40 species. The exact number depends on the source you look at. Four species and two hybrids are native to the Pacific Northwest.

It’s easy to distinguish the firs from other conifers in the Northwest. We can rule out the cedars with their flat leaves and the pines, which have long needles that grow in bundles. Now we just need to eliminate the spruces, hemlocks, larches, and Douglas fir (not a true fir, being in the genus Pseudotsuga.) 

Pacific Silver Fir Cones
You may be able to identify a fir by looking for the cones. The barrel-shaped cones are unique in two ways. First, they stand upright near the top of the tree like tiny owls. The cones of other native conifers hang down or point this way and that. However, if you are standing in a forest of large trees, you probably can’t see the cones. This is where the other unique character of fir cones will help. Rather than drop old cones like most other conifers, fir cones disintegrate on the tree when they disperse their seeds, leaving a thin spike on the tree. So if you are standing in a forest of conifers and there are no cones on the ground, they are probably all fir trees.

Grand Fir                    Noble Fir
Pacific Silver Fir         Subalpine Fir
A better way to identify a fir tree is to look at the needles. Unlike the short, unruly hemlock needles, fir needles are long and orderly like they had been combed. The needle tips of Northwest firs are soft, unlike the prickly spruces. The needles do not grow in bundles like those of pines and larches. As a final and definitive test for a fir, look at a twig that has lost its needles.  The scars left on the twig will be smooth and round. They are rare, but you might come across a yew, which has similar needles. You can tell the difference by looking at the lower surface of the needles. Each fir needle has two bands of white bloom on its lower surface. On the other hand, yew needles are a lighter shade of green underneath.

The firs are closely related and often look similar, which can make it difficult to tell one species from another. To make matters worse, when two species grow in the same locale, they often interbreed. For example noble fir (Abies procera) interbreeds with red fir (Abies magnifica). As you travel south in the Cascade Mountains of southern Oregon, noble fir begin to look more and more like red fir. You can see this change by observing the bracts that protrude from the cones of noble fir. As you go south, they become shorter and finally disappear from the cones of red fir. The hybrids are called Shasta Red Fir, (Abies magnifica x procera.)*

Considering the similarities and cross-breeding, it’s no surprise that there is so much disagreement about the number of fir species. The number in recent classifications ranges from 39 to 55. A Handbook of the World's Conifers by Aljos Farjon (2010) lists 47. Conifers of the World by James Eckenwalder (2009) lists 40.

Noble Fir
Everyone loves firs for their beauty. The varied hues, from the dark green Pacific silver fir to the bluish noble fir, and their iconic conic shape make them a favorite for landscaping and Christmas trees. Although fir lumber is not as strong as other conifers, it is widely used for plywood and framing lumber. You can find it in the lumber yard sold as “Hem-Fir.” This wood is one of the fir species or western hemlock (Tsuga heterophylla). The wood is soft with a light color that easily takes a stain, which makes it ideal for moldings used trim doors and windows. The light-colored wooden moldings you see at any lumber yard is likely Hem-Fir. The wood is not fragrant like cedar, but many products sold as “pine scented” get their fragrance from fir bark and foliage.

Northwest Fir Species
The following firs are native to the Pacific Northwest:
Grand fir (Abies grandis) – Needles flattened on twig. Grows below 5000 ft.
Noble fir (A. procera) – Needles bent like hockey sticks. Grows above 2000 ft.
Pacific silver fir (A. amabilis) – Needles dark green on top, pointing up & forward. Grows above 2000 ft.
Subalpine fir (A. lasiocarpa) – Needles curve upward with white lines on both sides. Grows above 4000 ft.

The following, which grow in the mountains of southwest Oregon, are considered to be hybrids* with white fir and red fir, which are native to California:
Shasta red fir (A.magnifica x procera) – Needles like noble fir.
White fir (A. Abies concolor x grandis) – Needles 2” long with white lines on both sides.

See also

*The Gymnosperm Database and Oregon Flora Project list these as Abies magnifica x procera..

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