South Dakota State Tree
Black Hills Spruce (common name)
Picea glauca var. densata (scientific name)
Black Hills spruce is a variety of white spruce (Picea glauca), a northern species that occurs principally in Canada and the northern United States, from Maine to Idaho, as well as Alaska. South Dakota's state tree, Picea glauca var. densata, is considered a geographical variety rather than a botanical variety of white spruce. It is the only spruce native to South Dakota, and it is not widely distributed in the state. It is localized to a few counties in the Black Hills region of the state, as well as adjacent areas in Wyoming. The Black Hills, most famous as the site of Mount Rushmore, are an isolated range on the western edge of the Great Plains. Black Hills spruce was designated as South Dakota's state tree in 1947.
Black Hills spruce is a conifer that grows up to 90 feet (27.4 m) tall with a 15- to 25-foot (4.6-7.6 m) spread. It has stiff evergreen needles with tiny, peg-shaped bases, arranged singly along the dense branches. Its cones hang down from the stem, and are 1 to 2 inches (2.5-5.1 cm) long, with thin rounded scales. Its male flowers are tan to pale red, and its female flowers are greenish to purplish. Older trees are often draped with a lichen called "old-man's-beard."
Height: 30-100 ft (9.1-30.5 m)
Diameter: up to 3.3 ft (1 m)
Bark: ashy gray or brown, fissured, thin flaky scales
Seed Cones: tan to brown, cylindrical, 1-2 in (2.5-5 cm) long
Leaves: bright green to bluish-green needles, 0.33-0.75 in (0.9-1.9 cm) long
Black Hills spruce is a very long-lived species that tends to grow slowly. It has a lifespan of 150 to 350 years.
This tree is found in the Black Hills area of South Dakota and Wyoming, as well as some cool canyons. It is a dominant species at higher elevations, gradually replacing quaking aspen, which forms the lower border of the spruce stands. It is an extremely hardy variety, tolerating temperatures as low as -50°F (-45.5°C).
IMPORTANCE TO LIVESTOCK AND WILDLIFE
Birds and mammals eat Black Hills spruce seeds. The bark provides food for porcupines. The tree provides good winter cover and supplies nesting sites for a variety of birds.
OTHER USES AND VALUES
The variety has been noted to have denser foliage, slower growth, and a greater tolerance to heat and drought than white spruce, making this a desirable variety to plant in the upper plains region. In addition, it requires little pruning, is deer-resistant, and tolerates drying winter winds well, making it an ideal choice as a windbreak or screen in home and farm landscapes. It has been planted throughout South Dakota, North Dakota, and Minnesota. It is also a popular Christmas tree, and has been used twice as the Capitol Christmas Tree in Washington, DC. Thousands of young trees are removed from the Black Hills National Forest and from plantations each year for use as Christmas trees.
Plains Indians used the inner bark and shoots for food, and the hardened sap for gum. They collected the wood for teepee poles.
The wood of Black Hills spruce is light, soft, and straight-grained. The soft wood is used for dimension lumber, pulp, boxes, and crates, but because of the limited local market, Black Hills spruce is not an important timber species.
Germination under established or mature stands commonly occurs on a variety of seedbeds—particularly on rotted logs and moss beds. Most propagation is by seed, but rooting and grafting have been used with success.
South Dakota's state tree grows best in heavy, acidic, moist, well-drained soil with full to partial sun. It can adapt to a variety of conditions including shade, drought, heat, and cold, as long as the site is well drained. The tree is flood intolerant and sensitive to soil compaction.
As the name implies, Black Hills spruce is found only in one location, the Black Hills of South Dakota and Wyoming. It normally grows at elevations of 5,700 to 6,700 feet (174-204 km) and in cool canyon bottoms.
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U.S. Forest Service
U.S. National Arboretum
U.S. Department of Agriculture
Author: World Trade Press