White spruce (Picea glauca): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table. Neighbouring spruces have their own pages: black spruce, red spruce and Engelmann spruce.

At a glance

Item	What the source records
Scientific name	Picea glauca (Moench) Voss, pine family (PLANTS and Silvics)
Other names, Silvics	Canadian spruce, skunk spruce, cat spruce, Black Hills spruce, western white spruce, Alberta white spruce and Porsild spruce
Native status, USDA PLANTS	Native in Alaska, Canada, the lower 48 states and Saint-Pierre and Miquelon
Size, Silvics	Trees more than 30 m (100 ft) tall and 60 to 90 cm (24 to 36 in) in diameter on good sites; the tallest reported more than 55 m (180 ft) and 90 to 120 cm (36 to 48 in) in diameter
Green weight of the wood, NRS-38	35 lb per cubic foot, without bark

Native range and climate

The Silvics of North America handbook (Agriculture Handbook 654, Volume 1, 1990) describes a range spanning the continent, running west from Newfoundland and Labrador along the northern tree line in Canada to Hudson Bay, the Northwest Territories and Yukon. In Alaska its range ends at Norton Bay on the Bering Sea and at Cook Inlet on the Gulf of Alaska. It extends south through British Columbia, east through Alberta and Manitoba, then southeast through northern Minnesota, northern Wisconsin, central Michigan, northeastern New York and Maine, with outliers in the Black Hills of Wyoming and South Dakota. The handbook gives elevations from sea level to 1,520 m (5,000 ft), and calls the tree a plastic species because it repopulated areas at the end of glaciation and grows under extreme climates and soils.

Silvics gives recorded extremes of minus 54 degrees C (minus 65 degrees F) in January and 34 degrees C (94 degrees F) in July at one northern study area, and up to 43 degrees C (110 degrees F) in Manitoba. Mean annual precipitation is 1,270 mm (50 in) in Nova Scotia and Newfoundland, falling to 250 mm (10 in) across the Northwest Territories, Yukon and parts of Alaska. The handbook gives a growing season of about 180 days in parts of Maine and about 20 days in parts of Canada, and says white spruce generally grows where it exceeds 60 days.

Growth, size and age

The handbook says shoot growth is determinate in older trees, with the following season's needles formed in the overwintering bud, and that shoot elongation is short: in northern Wisconsin the terminal leader finished 95 percent of its elongation 26 to 41 days after flushing. It says cessation of shoot growth depends more on day length than on temperature. On age, Silvics says the oldest trees occur on stress sites at the latitudinal or elevational tree line rather than on good sites: a partially rotted tree 16.5 cm (6.5 in) across on the Mackenzie River Delta showed a ring sequence of 589 years, and it adds that trees close to 1,000 years old grow north of the Arctic Circle. On good sites ages of 100 to 250 years are common, and the oldest, at 250 to 300 years, are frequently found in places protected from fire, such as islands.

Wood

The Wood Handbook (FPL-GTR-282, 2021) groups white, red and black spruce as eastern spruce, which it says are not distinguished from one another in commerce. It describes light-colored wood with little difference between heartwood and sapwood that dries easily and is stable after drying, moderately lightweight, easily worked, of moderate shrinkage, and moderately strong, stiff, tough and hard. It names pulpwood as the greatest use, with lumber for framing, general millwork, boxes and crates, and piano sounding boards. Silvics adds house logs, musical instruments, paddles and containers, and describes how people of interior Alaska used bark, roots and boughs.

Wood Handbook figure	Green	At 12% moisture content
Specific gravity (Table 5-3b)	0.33	0.36
Modulus of rupture, lbf per square inch (Table 5-3b)	5,000	9,400
Side hardness, lbf (Table 5-3b)	270	410

The green weight is in the NRS-38 table, the same figure used in the log weight calculator.

Damaging agents the handbook names

Fire. Silvics calls fire an important and sometimes dominant factor in forest dynamics throughout the range, and says mature forests are easily destroyed because of high susceptibility. It gives fire frequency as most commonly 60 to 200 years, and says fires at intervals under 40 or 50 years can eliminate the seed source.
Wind, snow and frost. Windthrow happens often at stand edges, and in stands thinned heavily, where soils are shallow or poorly drained and roots stay near the surface, and much less where a strong taproot or multilayered roots develop. Snow and ice can break up to 70 percent of the trees in stands. Flushing shoots are particularly susceptible to frost, and the handbook says seedlings are prone to frost heaving.
Bark beetles. Many bark beetles attack the species, mostly trees of low vigor, dying trees, windthrows and slash. The handbook says the spruce beetle, Dendroctonus rufipennis, also attacks trees of ordinary vigor and has killed large stands of white and other spruces, and that prolonged cold of minus 40 degrees kills large numbers of beetles in transition maritime climates such as parts of Alaska.
Defoliators. The spruce budworm and western spruce budworm are called the most destructive conifer defoliators, with sustained outbreaks having killed all spruce in some stands; see the spruce budworm page. The handbook also lists the yellowheaded spruce sawfly, European spruce sawfly, spruce spider mites and the European spruce needleminer. Eastern spruce gall adelgids cause cone-shaped galls on shoots.
Needle and bud rusts. Silvics says needle and bud rusts are common throughout the range and names Chrysomyxa ledicola as the most important cause of premature defoliation in Canada, with losses of up to 90 percent of that year's needles in western Canada. The witches' broom rust, C. arctostaphyli, frequently causes dead and deformed branches and reduced growth.
Root and trunk rots. The handbook calls Inonotus tomentosus a major cause of slow decline and death of trees in Saskatchewan, in patches of 0.4 ha (1 acre) or larger, the "stand-opening disease." It says rot cull is low in trees younger than 100 to 120 years and that most trees older than 200 years have significant rot. It describes white pine weevil damage as light compared with black or Norway spruce, with a weevil ecotype that is an important pest in interior British Columbia plantations.
Animals. Squirrels may harvest as much as 90 percent of the cone crop in Alaska, small mammals take large numbers of seeds, and young seedlings are damaged by rodents; the handbook says white spruce is not a preferred animal food.

For who takes reports of regulated pests, see reporting a pest in the United States, and pests and diseases by country sets out which ones agencies regulate.