The Gymnosperm Database
Subalpine forest dominated by
in the Entiat Valley, Washington [C.J. Earle, 2004.07.02].
A pair of mature, open-grown trees in the White Cloud Mtns. of Idaho [C.J. Earle, 2017.08.22].
A "skirted" tree in the Medicine Bow Mtns. of Wyoming. The low "skirt" spends the winter buried within the snowpack; the bare stems just above are zones where blowing ice crystals, bouncing along the snowpack, abrade and kill any exposed foliage; and the foliage farther above the snow surface is protected from winter abrasion by formation of rime [C.J. Earle, 2006.06.30].
A krummholz mat of
containing a small krummholz
; Golden Horn, Washington [C.J. Earle, 2015.07.05].
Krummholz mats showing frost damage from the prior winter; Middle Tiffany Mtn., Washington [C.J. Earle, 2000.07.21].
A very extensive krummholz mat, largely propagated through layering, in the Medicine Bow Mtns. of Wyoming. The foliage shows some frost damage from the prior winter. The background forest, all the way to the horizon, consists almost exclusively of
[C.J. Earle, 2006.07.01].
Two successive years of heavy cone crops on a mature tree at Tiffany Mtn., Washington [C.J. Earle, 2003.08.16].
Young, fertile seed and pollen cones. Seed cones on a tree typically become fertile before the pollen cones, as a defense against self-fertilization [C.J. Earle, 2006.07.03].
A squirrel created this cross-sectional view of a ripe seed cone [C.J. Earle, 2006.06.30].
Shade foliage in
is not 2-ranked, but assumes this "brushed" appearance in contrast to the morphology of sun foliage shown in the above photo [C.J. Earle, 2006.07.04].
Bark on a tree about 70 cm diameter [C.J. Earle, 2013.07.24].
Seedling about 10 cm tall, probably at least 2 years old [C.J. Earle, 2017.08.19].
Some specimens are exceptionally glaucous, and have given rise to cultivars sold as "blue spruce" in the trade [C.J. Earle, 2003.07.04].
Parry ex Engelmann 1863
Engelmann spruce, silver spruce, white spruce, mountain spruce (
), épinette d'Engelmann (Canadian French), pino real (Spanish) (
(described here) and
"In the northern part of its range, it hybridizes freely and completely intergrades with
). This hybrid is commonly called "interior spruce" or
. In the Chilliwack River Valley of British Columbia,
occurs with and hybridizes with
. The area is near sea level and the Fraser Valley, yet comes right out of the heart of the North Cascades. This hybrid may occur elsewhere, where the species' ranges are contiguous (such as the Federation Forest/Crystal Mountain area of Washington) but has not been seen yet (
Van Pelt 1999
). All three species (
P. engelmannii, glauca
) hybridize is a zone in the interior Skeena River valley in British Columbia (Sutton et al. 1994).
Additional synonymy for var.
(Moench) Voss subsp.
(Parry ex Engelmann) T.M.C. Taylor;
"Trees to 45 m, rarely to 60 m; trunk to 1.2 m, rarely 2 m diam.; crown narrowly conic. Bark gray to reddish brown. Branches spreading horizontally to somewhat drooping; twigs not pendent, rather stout, yellow-brown, finely pubescent, occasionally glabrous. Buds orange-brown, 3-6mm, apex rounded. Leaves 1.6-3(3.5) cm, 4-angled in cross section, rigid, blue-green, bearing stomates on all surfaces, apex sharp-pointed." Seed cones violet or deep purple, ripening buff-brown, "3-7(8) cm; scales diamond-shaped to elliptic, widest above middle, 13-20 × 9-16 mm, flexuous, margin at apex irregularly toothed to erose, apex extending 3-8mm beyond seed-wing impression. 2
Distribution and Ecology
Canada: Alberta, British Columbia; USA: Washington, Idaho, Montana, Wyoming, Colorado, Oregon, California, Nevada, Utah, Arizona, New Mexico; as krummholz at the alpine timberline (
). See also
. UHardy to Zone 3 (cold hardiness limit between -39.9°C and -34.4°C) (
Bannister and Neuner 2001
occurs in N Mexico and southern Arizona and New Mexico (
Taylor and Patterson 1980
: p.438) at 1000-3000 m in montane and subalpine forests.
Distribution data from
. Points plotted as tree icons represent isolated or approximate locations.
commonly finds its niche within one of four ecological settings. At the lowest elevation, it is a riparian tree with associates such as
. It may be that its ability to grow at these low elevations is due to cold air drainage, since it typically only occurs at these sites in confined valleys in close proximity to high mountains. At montane elevations, it is commonly a secondary component of conifer-dominated forests that typically have a predominance of
but also contain many other species; I've counted as many as 14 co-occurring conifer species in forests on the eastern slopes of the Cascades in Washington, yielding some peculiar associations, such as
. At subalpine elevations,
is one of the two codominants, along with
, of the spruce-fir forest type described by Oosting and Reed (1952); this forest accounts for the majority of the species' distribution, especially in the Rocky Mountains. Finally, it is a common timberline species throughout its range, often persisting to higher elevations than any other conifer. One of the most curious aspects of its timberline occurrence is the phenomenon of "traveling" krummholz, first described from Niwot Ridge, Colorado by Marr (1977) with estimates of rate of movement derived (using radiocarbon) by Benedict (1984). In this process, a krummholz tree layers and grows in its own lee while desiccation mortality caused by windblown ice (a phenomenon detailed by Hadley and Smith ) causes the tree's death on the windward side. As a result, the entire plant slowly moves downwind, leaving a trail of dead wood. I have seen this phenomenon at several sites in the Rocky Mountains and also at Cedar Breaks in Utah.
The largest tree, the North Joffre Spruce in British Columbia, is 220 cm dbh and 41 m tall. A tree named the Easy Pass Tower growing along the North Cascades Highway (Washington Route 20) near the Easy Pass Trailhead is 67.7 m tall and 169 cm dbh (Robert Van Pelt e-mail 2004.02.04). Quite a few comparably tall trees grow in the vicinity. A larger tree from the Payette Lake (Idaho) at 63 m
had the largest volume ever recorded for this species, but fell victim to bark beetles (
Van Pelt 1999
Tree FCC 23 in central Colorado had a crossdated age of 911 years (
, cited in
. Also, a crossdated age of 852 years for specimen FCC 19, collected in 1994(?) from a stand near the alpine timberline at the headwaters of Fool Creek in Fraser Experimental Forest, Colorado. Also, a crossdated age of 760 years for a specimen from near Peyto Glacier in Alberta collected by B.H. Luckman (
). I believe this was from a living tree collected in the late 1980s or early 1990s.
Have one Medicine Bow chronology (
), and numerous population studies exist.
This species is frequently harvested for timber and is moderately popular for soundboards of stringed instruments.
Engelmann spruce has been the second most popular selection for the
U.S. Capitol Christmas tree
, being used 10 times (as of 2017) since the tradition began in 1964. In democratic spirit, specimens have come from states throughout the species' range.
Engelmann spruce and subalpine fir form one of the most common forest associations in the Rocky Mountains. They can be seen, for example, in all Rocky Mountain National Parks from Jasper in Canada to Rocky Mountain in Colorado. They also form a dominant forest type in eastern North Cascades National Park and the Pasayten Wilderness in Washington. The southernmost Engelmann spruce stand in the U.S. can be found atop the Chiricahua Mountains of Arizona; this population is now referred to subsp.
Taylor and Patterson 1980
Benedict, J. B. 1984. Rates of tree‐island migration, Colorado Rocky Mountains, USA.
Hadley, J. L. and W. K. Smith. 1983. Influence of wind exposure on needle desiccation and mortality for timberline conifers in Wyoming, USA.
Arctic and Alpine Research
Marr, John W. 1977. The development and movement of tree islands near the upper limit of tree growth in the southern Rocky Mountains.
Oosting, H. J., and J. F. Reed. 1952. Virgin spruce‐fir of the Medicine Bow Mountains, Wyoming.
B. C. S. Sutton, S. C. Pritchard, J. R. Gawley, C. H. Newton, and G. K. Kiss. 1994. Analysis of Sitka spruce–interior spruce introgression in British Columbia using cytoplasmic and nuclear DNA probes.
Canadian Journal of Forest Research
This page co-edited with Michael P. Frankis, 1998.12.
Burns and Honkala 1990
LaRoi, G. H. and J. R. Dugle. 1968. A systematic and genecological study of
, using paper chromatography of needle extracts.
Canadian Journal of Botany
Van Pelt 1996
Copyright 2018 The Gymnosperm Database
Edited by Christopher J. Earle
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Last Modified 2018-01-20