The great fir debate

Dec 04, 2012
December ushers in Tree Hunting season at the Land Trust. For nine years, we've invited Land Trust supporters out to the Metolius Preserve to come cut their Christmas Tree, but the question remains, what kind of fir tree are we cutting?


December ushers in Tree Hunting season at the Land Trust. For nine years, we've invited Land Trust supporters out to the Metolius Preserve to help with forest restoration by cutting encroaching fir trees. The Preserve's fir trees are classic Christmas trees with soft, flat needles that have a whitish hue on the undersides and widely spaced branches with lots of room ornaments. But the question is, what kind of fir tree do we have at the Metolius Preserve?

There are two kinds of "Christmas Tree" fir that we have in our area: Grand Fir (Abies grandis) and White Fir (Abies concolor). They look very similar, but are generally considered distinct species. However, many think the differences have more to do with range. There seems to be a point of range overlap in the southern to central Oregon Cascades and Blue Mountains.

Historically, Grand fir was discovered by David Douglas in ~1830 and White fir by William Lobb during an expedition during 1849-1853. Give the slow rate of information dissemination in the 1800's, could it be that Mr. Lobb didn't know about or have an accurate description of Grand fir while on his expedition? Perhaps he presumed to have found a new species?

One way to tell them apart is that White fir needles have stomata, or small pores, on both leaf surfaces, while Grand fir only has them below. These stomata look white and give the needles a silvery sheen, thus the name White fir. Many locals commonly refer to Grand Fir as "White Fir" and vice versa depending on locality. Confused? Join the club!

The official line from the US Forest Service is that "Grand fir crosses with...the concolor variety of White fir. Several studies have shown hybridization and introgression between grand fir and white fir in a broad zone extending from the Klamath Mountains of northern California through southwestern Oregon and through the Oregon Cascade Range..."   

Here at the Land Trust we think we may have hybridized fir at the Metolius Preserve. However, most of the time we call our firs Grand fir...but if you dig too deep you'll hear White fir. Whatever you call them, we hope you'll head on out this weekend to cut your own!


** Many thanks to Rod Bonacker, US Forest Service and White Fir supporter, for his help on this blog post!