Subalpine Fir

Nature Notes by Dr. Frank Lang

I spent one Saturday with Dr. Charles Welden, Southern Oregon University’s community ecologist and Gene Parker, the local expert on true firs, on the summit of Mount Ashland taking a close look at the subalpine firs that grow there. Gene was checking out the firs for the Rogue River National Forest.

I always point out the clump of subalpine fir to students and field trippers when I am with them on the mountain. I tell them that its nearest neighbors are miles away in the Cascade Mountains and that it is a relict from the Ice Age. Maybe it’s a relict, maybe it’s a recent arrival. The jury is out on that one. To tell the truth, I had never really looked closely at the stand before this particular Saturday.

The stand appears low and scrubby with taller trees emerging above the knee to waist-deep foliage. The stand is some 300 feet around. The tallest trees are 18 or so feet high. The year I visited, the taller trees had purple, pitchy cones. Noble fir and white fir, the other true fir species on the mountain, also had a good cone year.

Subalpine fir, Abies lasiocarpa, is the most widespread of the true firs. It is found from the Yukon south through the Rocky Mountains to New Mexico and west along the Cascades and coast mountains to southern Oregon, with several scattered populations in northern California. Subalpine fir is most abundant near timberline. It can be the perfect picture of a true fir, tall and straight, conical, with short, stiff branches arranged in perfect whorls that extend to the ground. They are the perfect picture, unless they are krummholz. Krummholz – the trees look like the name sounds, low and gnarly. Krummholz, a German word that translates “crooked wood,” refers to dwarfed trees caused by harsh environmental conditions at the upper limit of tree growth.

Subalpine fir sometimes adapts to its harsh environment by layering. When its low, sweeping branches contact the moist organic accumulation of duff around the base of a tree, the branches root. Often, the tree whose branches have layered dies and rots away. The layered shrubby branches then form timber atolls. Timber, like coral atolls, have an open center with a circular fringe of shrubs or trees, instead of coral reefs.

Close examination of Mount Ashland’s subalpine firs yielded a surprise for me. Individual trees were indistinguishable. Elongated, horizontal branches covered the ground like giant serpents. The upright portions, including the taller trees, were not much more than upturned branches. There was no clear sign of individual trees.

The living trees on Mount Ashland are less than 80 years old. That is not to say the stand isn’t old. In the interior of the stand I found four distinct layers of branches from live ones on the surface to well rotted branches deeper in the soil. My impression was of an active stand of trees dealing with its precarious site by constant growth and renewal. At the edge of the bowl, the fir probably spends a good part of the year protected by a cornice of snow. Its greatest danger will come if human activity changes the snow accumulation pattern and exposes the stand to the howling winds of winter.

— Dr. Frank Lang   

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