''Picea engelmannii'', with the common names Engelmann spruce, white spruce, mountain spruce, and silver spruce, is a species of

spruce A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...

native to western

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. It is highly prized for producing distinctive tone wood for acoustic guitars and other instruments, it is mostly a high-elevation mountain tree but also appears in watered canyons.

Description

''Picea engelmannii'' is a medium-sized to large

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

tree growing to tall, exceptionally to tall, and with a trunk diameter of up to . The reddish bark is thin and scaly, flaking off in small circular plates across. The crown is narrow conic in young trees, becoming cylindric in older trees. The shoots are buff-brown to orange-brown, usually densely pubescent, and with prominent pulvini. The

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

are needle-like, long, flexible, rhombic in cross-section, glaucous blue-green above with several thin lines of

stomata In botany, a stoma (: stomata, from Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange between the internal air spa ...

, and blue-white below with two broad bands of stomata. The needles have a pungent odour when crushed. Purple cones of about appear in spring, releasing yellow pollen when windy. The cones are pendulous, slender cylindrical, long and broad when closed, opening to broad. They have thin, flexible scales long, with a wavy margin. They are reddish to dark purple, maturing to light brown 4–7 months after pollination. The

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s are black, long, with a slender, long light brown wing. The tree grows in a '' krummholz'' form along the fringe of alpine tundras.

Distribution

Engelmann spruce is mostly a higher-elevation mountain tree, in many areas reaching the

tree line The tree line is the edge of a habitat at which trees are capable of growing and beyond which they are not. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually low ...

, but at lower elevations occupies cool watered canyons. It grows from above sea level, rarely lower towards the northwest. Englemann spruce is native to western

, common in the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

and east slopes of the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington (state), Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as m ...

from central

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

to Southern Oregon in the Cascades and

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

, and

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

, and more sparsely towards

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

and

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

in the Sky islands; there are also two isolated populations in

Northern Mexico Northern Mexico ( ), commonly referred as , is an informal term for the northern cultural and geographical area in Mexico. Depending on the source, it contains some or all of the states of Baja California, Baja California Sur, Chihuahua (state), ...

. It appears in the canyons of the

Idaho Panhandle The Idaho panhandle—locally known as North Idaho, Northern Idaho, or simply the Panhandle—is a salient region of the U.S. state of Idaho encompassing the state's 10 northernmost counties: Benewah, Bonner, Boundary, Clearwater, Idaho, ...

and more limitedly in the northeastern

Olympic Mountains The Olympic Mountains are a mountain range on the Olympic Peninsula of the Pacific Northwest of the United States. The mountains, part of the Pacific Coast Ranges, are not especially high – Mount Olympus (Washington), Mount Olympus is the high ...

, which features some exceptionally large specimens, including one in diameter and tall. It can be found in the

, mostly on the eastern slopes, from elevations of and liberally in the

. It can also be found in the Monashee and

Selkirk Mountains The Selkirk Mountains are a mountain range spanning the northern portion of the Idaho Panhandle, eastern Washington, and southeastern British Columbia which are part of a larger grouping of mountains, the Columbia Mountains. They begin at Mic ...

, as well as the highlands surrounding the Interior Plateau.

Ecology

Because transpiration is greatly reduced in small saplings while engulfed in snowpack, increased rates of

transpiration Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. It is a passive process that requires no energy expense by the plant. Transpiration also cools plants, c ...

in response to loss of snowpack, coupled with low sapwood water reserves and an extended period of soil frost in windswept areas, may prevent Engelmann spruce from regenerating in open areas both above and below the tree line. Both water uptake and water stored in

root In vascular plants, the roots are the plant organ, organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often bel ...

s appear to be critical for the survival of subalpine Engelmann spruce saplings that are exposed above the snowpack in later winter to early spring.Boyce, R.L. and Lucero, S.A. 1999. Role of roots in winter water relations of Engelmann spruce saplings. Tree Physiol. 19:893–898. For exposed trees, the availability of soil water may be critical in late winter, when transpirational demands increase. Cuticular damage by windblown ice is probably more important at the tree line,Hadley, J.L.; Smith, W.K. 1983. Influence of wind exposure on needle desiccation and mortality for timberline conifers in Wyoming, USA. Arctic Alpine Res. 15:127–135. (Cited in Coates et al. 1994).Hadley, J.L.; Smith, W.K. 1986. Wind effects on needles of timberline conifers seasonal influence on mortality. Ecology 67:12–19. Cited in Coates et al. (1994). but damage caused by desiccation is likely to be more important at lower elevations. Despite wind damage, the species tends to grow taller than others at the tree line. It is

shade tolerant In ecology, shade tolerance is a plant's ability to tolerate low light levels. The term is also used in horticulture and landscaping, although in this context its use is sometimes imprecise, especially in labeling of plants for sale in nursery (ho ...

, but not so much as subalpine fir, rendering it somewhat dependent on fires to outgrow competitors, although its thin bark and shallow roots make it vulnerable to fire. Spruce bark beetles attack the tree, being particularly deadly to groups which have stood for centuries. It is also susceptible to avalanches. Although older spruce forests are not very useful to animals for forage, they can become so after fires, as they often burn completely, allowing many other plants, especially deciduous, to rise. Engelmann spruce-shaded streams are exploited by

trout Trout (: trout) is a generic common name for numerous species of carnivorous freshwater ray-finned fishes belonging to the genera '' Oncorhynchus'', ''Salmo'' and ''Salvelinus'', all of which are members of the subfamily Salmoninae in the ...

, and

aphid Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...

s produce

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or war ...

s which hang from the tree and look similar to cones when they dry out.

Subspecies and hybrids

Engelmann spruce below Boulder Pond Payette NF

Two geographical subspecies (treated as varieties by some authors, and as distinct species by others) occur: *''Picea engelmannii'' subsp. ''engelmannii'' (Engelmann spruce). All of the range except as below. *''Picea engelmannii'' subsp. ''mexicana'' (Mexican spruce). Two isolated populations on high mountains in northern Mexico, on the Sierra del Carmen in

Coahuila Coahuila, formally Coahuila de Zaragoza, officially the Free and Sovereign State of Coahuila de Zaragoza, is one of the 31 states of Mexico. The largest city and State Capital is the city of Saltillo; the second largest is Torreón and the thi ...

(

Sierra Madre Oriental The Sierra Madre Oriental () is a mountain range in northeastern Mexico. The Sierra Madre Oriental is part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that ...

) and on Cerro Mohinora in Chihuahua (

Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through northwestern and western Mexico, and along the Gulf of California. The Sierra Madre is part of the American C ...

). Engelmann spruces of the Madrean sky islands mountains in the extreme southeast of Arizona and southwest of New Mexico also probably belong to this subspecies, though this is disputed. The Engelmann spruce hybridises and intergrades extensively with the closely related white spruce (forming a species complex known as '' Picea × albertiana''; Alberta spruce, or interior spruce) in interior Canada, and to a lesser extent with the closely related

Sitka spruce ''Picea sitchensis'', the Sitka spruce, is a large, coniferous, evergreen tree growing to just over tall, with a trunk diameter at breast height that can exceed 5 m (16 ft). It is by far the largest species of spruce and the fifth- ...

where they meet on the western fringes of the Cascades.

Uses

Native Americans made various medicines from the resin and foliage. Engelmann spruce is of economic importance for its

wood Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin t ...

, being light and fairly strong. It is harvested for

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses, Feces#Other uses, herbivore dung, or other vegetable sources in water. Once the water is dra ...

-making and general construction. Wood from slow-grown trees at high elevation is especially prized for making soundboards for musical instruments such as acoustic

guitar The guitar is a stringed musical instrument that is usually fretted (with Fretless guitar, some exceptions) and typically has six or Twelve-string guitar, twelve strings. It is usually held flat against the player's body and played by strumming ...

harp The harp is a stringed musical instrument that has individual strings running at an angle to its soundboard; the strings are plucked with the fingers. Harps can be made and played in various ways, standing or sitting, and in orchestras or ...

violin The violin, sometimes referred to as a fiddle, is a wooden chordophone, and is the smallest, and thus highest-pitched instrument (soprano) in regular use in the violin family. Smaller violin-type instruments exist, including the violino picc ...

s, and

piano A piano is a keyboard instrument that produces sound when its keys are depressed, activating an Action (music), action mechanism where hammers strike String (music), strings. Modern pianos have a row of 88 black and white keys, tuned to a c ...

s. Because it is odourless and has little resin, it has been used for food containers such as barrels. It is also used to a small extent as a

Christmas tree A Christmas tree is a decorated tree, usually an evergreen pinophyta, conifer, such as a spruce, pine or fir, associated with the celebration of Christmas. It may also consist of an artificial tree of similar appearance. The custom was deve ...

Gallery

File:Picea engelmannii foliage cones.jpg, Forest, with mature female cones in foreground File:Picea engelmannii UGA1.jpg, Dangling somewhat immature (unopened) female cone File:Picea engelmannii UGA2.jpg, Dangling mature female cone File:Engelmann Spruce cones RMNP.jpg, Purple immature cones and yellow mature cones from the previous year. No male pollen cones are visible; the brownish-golden branch tips are protective bud scales being shed from the spruce buds

References

External links

Jepson Manual Treatment
– Photographs related spruce cones
CalPhotos
{{Authority control engelmannii Flora of the Northwestern United States Flora of the Southwestern United States Flora of Alberta Flora of British Columbia Flora of Coahuila Flora of Chihuahua (state) Flora of New Mexico Flora of Nuevo León Flora of Sonora Flora of Tamaulipas Plants described in 1863 Taxa named by George Engelmann Taxa named by Charles Christopher Parry Trees of Northern America