White Spruce (Glauca)

The White Spruce (Glauca) is generally described as a perennial tree. This is native to the U.S. (United States) has its most active growth period in the summer . The greatest bloom is usually observed in the late spring, with fruit and seed production starting in the summer and continuing until summer. Leaves are retained year to year. The White Spruce (Glauca) has a moderate life span relative to most other plant species and a slow growth rate. At maturity, the typical White Spruce (Glauca) will reach up to 100 feet high, with a maximum height at 20 years of 30 feet.

The White Spruce (Glauca) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by bare root, container, cuttings, seed. It has a slow ability to spread through seed production and the seedlings have low vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -65°F. has high tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

The wood of white spruce is used primarily for pulpwood and lumber for various construction, prefab houses, mobile homes, furniture, boxes and crates, and pallets. It also is used for house logs, musical instruments, and paddles. Because of its wide geographic range and abundance, it is (de facto) highly significant for food and cover of many wildlife species, for soil stability, watershed value, and recreation. It was historically important for food, shelter, medicine, fuel, and other uses by American Indians. White spruce is the provincial tree of Manitoba and the state tree of South Dakota. White spruce is much used in some areas for Christmas trees and is a good ornamental and shade tree.

General Characteristics

General: Pine Family (Pinaceae). Native trees grows to 25 (-50) meters tall, the crown broadly conic to spire-like, or the plants sometimes shrub-like near treeline; branches slightly drooping; twigs not pendent, slender, pinkish-brown, without hairs. Bark is gray-brown, thin scaly. Needles are evergreen, borne singly from all sides of the twig but often crowded on the upper side, (0.8-) 1.5-2 (-2.5) cm long, blue-green, 4-angled, often inwardly curved, stiff, sharp-pointed. Seed cones are light brown at maturity, 2.5-6 (-8) cm long, ellipsoid, pendent; cone scales fan-shaped, soft and flexible, the tip smooth-edged and extending 0.5-3 mm beyond seed-wing impression. The common name is derived from the white waxy layer on the foliage.

Variation within the species: White spruce is highly variable over its range and several varieties (apart from the typical) have sometimes been recognized. P. glauca var. albertiana (S. Brown) Sargent – Canadian Rocky Mountains P. glauca var. densata Bailey – Black Hills of South Dakota and adjacent Wyoming P. glauca var. porsildii Raup – Alaska

The diagnostic characteristics of these variants are not well correlated and occur rather sporadically – some of the features may reflect interspecific hybridization and some may be phenotypic modifications. More study is needed, but recent taxonomic treatments do not formally recognize variants within white spruce. Most of the variation follows gradients of latitude and altitude.

Where they occur together, white spruce and Engelmann spruce regularly hybridize and intergrade completely, the hybrids occurring in intermediate elevation. Such trees are largely the basis for the description of P. glauca var. albertiana. White spruce also forms natural hybrids with Sitka spruce and black spruce.

Required Growing Conditions

Widespread across northern North America, from Alaska, Yukon, and British Columbia continuously eastward to Nova Scotia, Newfoundland, New Brunswick, and Québec, in the northeastern United States and sporadically in the northern tier of states (Montana, Wyoming, South Dakota, Minnesota, Wisconsin, Michigan). For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Cultivation and Care

Adaptation: In muskegs, bogs, and river banks, to montane slopes; at 0-1000 (-2100) meters elevation. White spruce is a dominant tree of interior forests in Canada and Alaska and often an early colonizer in succession. White spruce co-occurs with black spruce (Picea mariana) over a wide range – the two species have evolved a complex competitive relationship (habitat partitioning) involving contrasts in water tolerance, vegetative reproduction, flowering times, and rate of early growth. Picea glauca grows best on well-drained mineral soils with deep or no permafrost, while P. mariana is more tolerant of sites with flooding, permafrost, and high soil acidity.

Planting: Cone crops have been reported for trees as young as 4 years, but seed production in quantity begins at age 30 or older for most natural stands. Good years of seed production may be 2-12 years apart.

Germination under established or mature stands commonly occurs on a variety of seedbeds – particularly on rotted logs and moss beds, but exposed mineral soil after windthrow and floods is the best seedbed. Large numbers of white spruce may become established immediately following disturbance. Seedling growth is greatest at full light intensity, but white spruce is capable of reproducing under mature stands of spruce and early succession tree species. Because seedling and juvenile growth of white spruce is slower than its early successional associates, it remains in the understory for 50 to 70 years. Trees 100-250 years old are common on good sites; older trees (250 to 300 years) are frequently found in areas protected from fire and in relatively wet upland situations. As in other species, maximum age appears to occur on stress sites at latitudinal or elevational treeline. Trees 500-1000 years old are known from such sites.

General Upkeep and Control

White spruce trees from very young to 200 or more years may show good growth after release resulting from natural causes or silvicultural treatment.

Mature forests with white spruce are easily destroyed because of their high susceptibility to fire. The probability of elimination of this species increases with latitude because good seed years become infrequent and seed quality poorer. At relatively short fire intervals (less than 40-50 years) the source of white spruce seed can be eliminated.

Delivery of seeds to seedbeds for germination may limit regeneration. Squirrels may harvest as much as 90 percent of the cone crop in Alaska. Seed predation by insects and small mammals such as deer mice, red-backed and meadow voles, chipmunks, and shrews also can result in significant seed loss.

Slow initial root growth makes young seedlings and transplants particularly susceptible to frost heaving. The severity of damage generally is greatest on fine-textured and wet soils where water is adequate for ice crystal formation in the surface soil. Defoliation by the spruce budworm and the western spruce budworm can cause mortality if defoliation continues for 2 or more years.

Plant Basics
Category
Growth Rate Slow
General Type Tree
Growth Period Summer
Growth Duration Perennial
Lifespan Moderate
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Late Spring
Displays Fall Colors No
Shape/Growth Form Single Stem
Drought Tolerance High
Shade Tolerance Intermediate
Height When Mature 100
Vegetative Spread Slow
Flower Color Yellow
Flower Conspicuousness No
Fruit/Seed Abundance Low
Fruit/Seed Seasonality Summer Summer
Seed Spread Rate Slow
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Container, Cuttings, Seed
Moisture Requirements Medium
Cold Stratification Required Yes
Minimum Temperature -65
Soil Depth for Roots 30
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 4–8.2 pH
Precipitation Range 7–7 inches/yr
Planting Density 300–700 indiv./acre
Soil Textures Coarse, Fine, Medium
Soil Depth for Roots 30
Minimum Frost-Free Days 60 day(s)
Salinity Tolerance Low
CaCO3 Tolerance Low
Sustainability & Use
Leaf Retention Yes
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database, plants.usda.gov.
National Plant Data Center, Baton Rouge, LA 70874-4490 USA