Cones on a tree near timberline, Great Basin National Park, Nevada [C.J. Earle].  A group of tree clumps near timberline in the Medicine Bow Mountains of Wyoming [Dr. Linda B. Brubaker, Aug-1990]. |
Picea engelmannii Parry ex Engelmann 1863
Common NamesEngelmann spruce, silver spruce, white spruce, mountain spruce (6), épinette d'Engelmann (Canadian French), pino real (Spanish) (1).Taxonomic notesSyn: P. engelmannii Parry (8). Two subspecies, engelmannii (described here) and mexicana."Although P. engelmannii varies considerably over its broad distributional range, the variation is continuous, militating against recognition of multiple varieties" (9). "In the northern part of its range, it hybridizes freely and completely intergrades with P. glauca " (1). In the Chilliwack River Valley of British Columbia, it occurs with and hybridises with Picea sitchensis. 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 (3). Additional synonymy for var. engelmannii: Picea glauca (Moench) Voss subsp. engelmannii (Parry ex Engelmann) T.M.C. Taylor; P. columbiana Lemmon; P. engelmannii var. glabra Goodman (1). Description"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. 2n=24" (1).RangeCanada: Alberta, British Columbia; USA: Washington, Idaho, Montana, Wyoming, Colorado, Oregon, California, Nevada, Utah, Arizona, New Mexico; as krummholz at the alpine timberline (1). See also (10). USDA hardiness zone 3-4. The subsp. mexicana occurs in N Mexico and southern Arizona and New Mexico (9: p.438) at 1000-3000 m in montane and subalpine forests.Big TreeHeight 56.7 m, dbh 192 cm and crown spread 8.2 m in 1987, on the Icicle Creek Trail in the Alpine Lakes Wilderness, WA. Two other larger trees were known from the North Cascades (Washington) and Payette Lake (Idaho), but the former was killed in a flood and the latter, which at 63m 3 had the largest volume ever recorded for this species, fell victim to bark beetles (3).OldestA 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 (2). I believe this was from a living tree collected in the late 1980s or early 1990s.DendrochronologyHave one Medicine Bow chronology (7), and numerous population studies exist.EthnobotanyObservationsEngelmann 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. mexicana (9: p.438).Remarks
Citations(1) Ronald J. Taylor at the Flora of North America web site .(2) Brown, Peter M.; Wayne D. Shepard; Christopher C. Brown; Stephen A. Mata and Douglas L. McClain. 1995. Oldest known Engelmann spruce. USDA Forest Service Rocky Mountain Forest and Range Experiment Station Research Note RM-RN-534. (3) Robert Van Pelt, personal communication 1-Mar-1999. (4) American Forests 1996 . (6) Peattie 1950 . (7) Earle 1993 . (8) Silba 1986 . (9) Taylor, R. J. & T. F. Patterson. 1980. Biosystematics of Mexican spruce species and populations. Taxon 29 (4): 421-469 (10) Robert S. Thompson, Katherine H. Anderson and Patrick J. Bartlein. 1999. Atlas of Relations Between Climatic Parameters and Distributions of Important Trees and Shrubs in North America. U.S. Geological Survey Professional Paper 1650 A&B. URL= http://greenwood.cr.usgs.gov/pub/ppapers/p1650-a/pages/conifers.html, accessed 22-Jan-2000.
See also
This page co-edited with Michael P. Frankis, Dec-1998. |
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