Northern Ontario Plant Database
Picea glauca (Moench) Voss
En: white spruce, cat spruce, skunk spruce, northern spruce, Labrador spruce, Porsild spruce, single spruce, western white spruce, Alberta white spruce, pasture spruce
Pinaceae (Pine Family)
General: A tall evergreen tree, to 30 m tall. The common names cat, skunk, and cat-piss spruce refer to the odor of the broken needles, which smell like a cat's litter box; thus, white spruce is undesirable for use as a Christmas tree. White spruce is an important source of wood for the pulp and paper industry.
Stems/twigs: Young twigs are pale greenish-white, glaucous, and smooth (glabrous), older twigs are pale brown and glabrous. The ovate buds are reddish brown with many overlapping rows of thin bud scales. The bark is grayish-brown and scaly.
Needles: Evergreen, simple, and stalked. Needles are slender, stiff, 15—22 mm long, spirally arranged around the stem, green to bluish-green, glabrous, often glaucous, and 4-angled in cross-section with a distinct white line along each side, formed by 2 rows of small white dots (stomates). The tips of the needles are stiff and pointed (acute) to sharply pointed (acuminate). Needles narrow abruptly at the base to woody peg-like attachments (sterigmata), which are decurrent along the stem.
Reproductive structures/cones: Unisexual, with separate male and female reproductive structures (cones) borne on the same plant (monoecious). Male cones are ovoid, clustered near the branch ends, erect, and deciduous after pollen is shed. Female cones are cylindrical, 3—6 cm long, terminal, and erect when young, but pendant in fruit. Immature seed cones are reddish-purple; cone scales are open during pollination, but the scales then close tightly until the seeds reach maturity in last summer. Mature cones are light brown; cone scales are ovate with rounded margins. The winged seeds are shed throughout the fall and winter. Cones are deciduous, dropping after the seeds are released.
Habitat and Range: Rich, well-drained soils in mixedwood and coniferous forests, fields, stream margins, riverbanks, and upland slopes. White spruce, native to boreal North America, has a trans-Canadian range that extends from Newfoundland and Labrador to British Columbia.
Similar Species: Black spruce (Picea mariana (Mill.) B.S.P.) is a tall evergreen tree with drooping branches; it often reproduces vegetatively by layering (rooting of branches on the ground). Like all spruce, black spruce has stiff pointed 4-angled needles, but the twigs of black spruce bear short brown hairs and small glandular hairs, visible with a hand lens. The seed cones of black spruce are ovoid, 2—3 cm long, and reddish-purple to dark purplish-brown when young; they remain in the club-like crown of the tree for many years. Black spruce seeds are released by fire or extreme heat and require bare mineral soil to germinate. Black spruce prefers wet, poorly-drained organic soils and is frequently found in and around bogs and swamps; it also grows in shallow soil on nutrient-poor sites.
Red spruce (Picea rubens Sarg.), an upland to subalpine maritime species, is restricted to eastern Ontario and is not found in the Algoma District; its twigs are pubescent with slender, non-glandular hairs.Back to species list