Utah State Tree
Blue Spruce (common name)
Picea pungens (scientific name)
Blue spruce is the most popular conifer in the United States. It is prized for the color of its needles, which at their best are a distinctive, deep silver-blue to dark green. The coloration is due to a powdery, waxy bloom on the surface of the needles. Individual trees differ in coloration, and some are a plainer dark green or even yellowish green or white.
Blue spruce is native to the Rocky Mountain region, but it is widely cultivated elsewhere. Although the tree is often called Colorado blue spruce, this is only an alternate common name and does not refer to any particular species or variety. Other common names for blue spruce include Colorado spruce, silver spruce, and pino real. Blue spruce is the official state tree for both Utah and Colorado. Colorado's state tree was designated in 1939, and Utah designated blue spruce in 1933.
Blue spruce is a native evergreen tree with a dense, pyramid-shaped to spire-shaped crown. At maturity, it normally reaches about 100 feet (30 m) tall with a diameter of approximately 3 feet (0.91 m). Branches are stout and hang horizontally to drooping. The needles are stiff with sharp points, approximately one inch long, and can range greatly in color in wild populations. Needle color can run from white to yellowish to deep frosty blue to dark green. Cones have thin, flexible scales. Blue spruce seeds are 0.13 inch (0.3 cm) long, about half the length of the wings.
Height: 70-115 ft (21-35 m)
Diameter: up to 5 ft (1.5 m)
Bark: gray to red-brown, 0.75 to 1.5 inches (1.9-3.8 cm) thick
Seed: 2.5-4 in (6.4-10.2 cm) long, cylindrical with thin, pointy scales
young: reddish to violet
mature: light brown
Leaves: stiff needles 0.6-1.25 inches (1.5-3.2 cm) long, silvery or deep blue, yellowish-green, dark green, or white
Blue spruce is a slow-growing tree. It has a moderate lifespan, normally living for 30 to 50 years. Some trees live to be more than 200 years old. The oldest blue spruces recorded lived for more than 600 years.
This species is native to western North America. It grows mainly in cool climates that are subhumid to humid, characterized by low summer temperatures and low winter precipitation. In the southern end of its range, however, it may be restricted to areas near water sources in arid and semiarid climates. Average annual precipitation in blue spruce habitats varies from 18 to 24 inches (46-61 cm).
Blue spruce shares its habitat with cottonwoods, Engelmann spruce, white fir, Douglas-fir, Mountain maple, thin-leaf mountain alder, Utah honeysuckle, Gambel oak, Saskatoon serviceberry, and common juniper.
IMPORTANCE TO LIVESTOCK AND WILDLIFE
Blue spruce is not a highly preferred food for either wildlife or domestic animals. Blue spruce provides cover for a variety of bird and animal species, including elk, mule deer, white-tailed deer, small mammals, and small birds in Colorado, Utah, and Wyoming. Big game forage blue spruce in northern New Mexico and southern Colorado. Numerous birds eat blue spruce seeds and rely on blue spruce for summertime nesting. Red squirrels in Utah store blue spruce cones.
OTHER USES AND VALUES
Because blue spruce is relatively scarce and the wood is brittle and often full of knots, it is not an important tree for lumber or wood products.
Because of its symmetry and beautiful color, blue spruce is planted extensively as an ornamental in North America and Europe. It is also a popular Christmas tree choice.
In deer country, blue spruce is valuable as a landscape plant because its prickly texture and strong aroma make it deer-resistant.
Blue spruce reproduces sexually. Natural vegetative reproduction does not occur, although shoots sometimes sprout on the trunks. Seed production begins at about 20 years and peaks at 50 to 150 years.
Because blue spruce has shallow roots, it is restricted to moist sites where water is close to the surface. Blue spruce occurs on mountain stream banks, well-drained floodplains or cobble flats, first-level terraces, ravines, intermittent streams, and subirrigated slopes.
Blue spruce is found in the central and southern Rocky Mountains as well as the Wasatch and Uinta mountains. It grows at elevations between 6,000 and 11,500 feet (1,750-3,500 m), but does not reach the alpine tree line. It grows in scattered populations in eastern Idaho and western Wyoming, and better developed populations in Utah and Colorado. Blue spruce's range continues southward into Arizona and New Mexico. It occurs rarely in north-central Montana.
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U.S. Forest Service
U.S. National Arboretum
U.S. Department of Agriculture
Author: World Trade Press