| Picea engelmannii | |
|---|---|
| Foliage and cone | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Pinales |
| Family: | Pinaceae |
| Genus: | Picea |
| Species: | P. engelmannii |
| Binomial name | |
| Picea engelmannii Parry ex Engelm. |
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Picea engelmannii (Engelmann Spruce) is a species of spruce native to western North America, from central British Columbia and southwest Alberta, southwest to northern California and southeast to Arizona and New Mexico; there are also two isolated populations in northern Mexico. It is mostly a high altitude mountain tree, growing at 900-3650 m altitude, rarely lower in the northwest of the range; in many areas it reaches the alpine tree line.
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Picea engelmannii is a medium-sized to large evergreen tree growing to 25-40 m tall, exceptionally to 65 m tall, and with a trunk diameter of up to 1.5 m. The bark is thin and scaly, flaking off in small circular plates 5-10 cm 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 are needle-like, 15-30 mm long, rhombic in cross-section, glaucous blue-green above with several thin lines of stomata, and blue-white below with two broad bands of stomata.
The cones are pendulous, slender cylindrical, 4-8 cm long and 1.5 cm broad when closed, opening to 3 cm broad. They have thin, flexible scales 15-20 mm long, with a wavy margin. They are reddish to dark purple, maturing pale brown 4–7 months after pollination. The seeds are black, 2-3 mm long, with a slender, 5-8 mm long pale brown wing.
Two geographical subspecies (treated as varieties by some authors, and as distinct species by others) occur:
Picea engelmannii, Engelmann Spruce, hybridises and intergrades extensively with the closely related White Spruce found further north and east in the Rocky Mountains, and to a lesser extent with the closely related Sitka Spruce where they meet on the western fringes of the Cascades.
Engelmann Spruce is of economic importance for its wood, harvested for paper-making and general construction. Wood from slow-grown trees at high altitude has a specialised use in making acoustic guitars and harps. It is also used to a small extent as a Christmas tree.
Outbreaks of spruce beetles have destroyed millions of Englemann Spruce trees.
Media related to Picea engelmannii at Wikimedia Commons