Location: North center of Sieg Hall, south of the walking path between Sieg and Allen Library

Summary: Another of our four native Washington Fir species, this dark symmetrical tree may be compared with the Grand Fir already noted on this tour. This specimen has the common Abies trait of needles with notched tips and cruciform (cross-shaped) growing pattern, but unlike the straight parted needles of the Grand Fir, a Pacific Silver Fir bears all of their needles stretched forward towards the tip of the branch. On the underside of each notched needle are two bright white/silver lines, making it easy to see where this tree got its common name. These white lines are the tree’s stomatal bands, the tiny holes through which the leaf exchanges gas with the atmosphere in order to perform photosynthesis. The contrast between the dark glossy green tops and almost white undersides of this species is striking, and can act as a good identification feature. This magnificent tree grows from Oregon to British Columbia and ranges from sea level in its northern range to above 1000 feet near the California border. Younger specimens bear distinct “eye” marks on the bark where old branches have fallen away, and have small bubbles filled with sap. As the tree ages this bark becomes rougher and develops fissures. Growing as high as 200’, the dense foliage casts a deep shade beneath these trees, and often the mid-elevation forests this species dominates will be composed of large trunks which sometimes rise to greater than 100 feet without a single branch (after all, why put out leaves in the lower canopy if there is no light for them to reach).

A truly remarkable feature of such a forest may be found by asking the question, if the mature Silver Fir block out the sunlight, then how does this tree regenerate? Newly germinated trees are destined to a dark start to life under the shadows of their parents, and they occupy this darkness at a time where they lack the vast stores of energy that older trees contain. After sprouting, a Silver Fir sapling will often spend between 70 to 200 years as small sapling, growing very slowly and perhaps gaining a bit of extra energy by connecting its roots to those of a mature specimen until one day BOOM, a big tree dies! This event (often a literal windfall) will open a patch in the canopy where sunlight provides the long-suffering sapling the opportunity to race for the gap and reach its full potential as a mature Pacific Silver Fir, often living for as long as 400 years or more. Such long life-cycles are one of the reasons that human-induced pressures like climate change and clearcut logging have a high impact on trees, whose natural processes are measured in far more than a single human lifespan. This tree is currently the University’s only specimen of this native species. 

Historical Background: This fir does not have highly valuable wood for lumber as it is not resistant to decay. However, tribes in this region have used the boughs as floor bedding. Its pitch was also chewed as gum. Today, this tree's pulp is often used in papermaking.  

Native Range: Oregon Cascades to coastal B.C., rare in the Oregon Coast ranges and above 1000 feet in the southern end of its range, down to sea level in Canada.

Identifying Features: The Pacific Silver fir exhibits a luscious dark green on the top of its notch tipped needles, but the bottom, with its two or more stomatal bands, is an distinctive milky green. The difference between the two sides is intense and may be used as a hint regarding the trees identity when comparing it with other firs.  Fully grown trees of this species are tall and dense. As with other firs, the branches and new growth odient in cruciform growing pattern (sets of 3). Needles grow on all sides of the Pacific silver fir, but the bottom needles grow out horizontally and towards the tip, making it appear at first glance as though there is a 3 sided leafing pattern. Needles on the top of the branch grow forward and lie against it.

Identifying Features In Depth:

1. Form: Growth to a height of 180” (55m) with high apical control in a conical to cylindrical shape, with dense foliage and symmetrical pattern.

2. Leaves: Flat evergreen needles with notched tips and a grooved top, dark luscious green on top, light in color on bottom with 2 or more stomatal bands. Needles form flattened along the branches, with needles on the bottom curving out horizontally on the side like those of a grand fir and those on top laying against the branch pointed forward.

3. Bark: Bark begins whitish gray and smooth, with small resin bubbles. As it ages it becomes scaly.

4. Reproductive Bodies: Male pollen cones are reddish, seed cones are erect and shaped like a barrel, often dark purple in color. They fall apart while still standing on the tree releasing long winged seeds. Cones are 3-5’ (8-12cm) long.