Black spruce (Picea mariana): 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.

At a glance

Item	What the source records
Scientific name	Picea mariana (Mill.) B.S.P., pine family
Other names	Bog spruce, swamp spruce and shortleaf black spruce (Silvics)
Native status, USDA PLANTS	Native in Alaska, Canada, the lower 48 states and on Saint-Pierre and Miquelon
Size, Silvics	At maturity an average of 12 to 20 m (40 to 65 ft) tall and about 23 cm (9 in) in diameter on good sites, 8 to 12 m (25 to 40 ft) and about 13 cm (5 in) on poor sites; occasional trees about 27 m (90 ft) tall and 46 cm (18 in) across in the Ontario Clay Belt
Age, Silvics	Average maximum age about 200 years, with ages up to 280 years reported
Green weight of the wood, NRS-38	35 lb per cubic foot, without bark

Native range

The Silvics of North America handbook (Agriculture Handbook 654, volume 1, 1990) calls black spruce a wide-ranging, abundant conifer of the northern parts of North America, and says it is the most important pulpwood species of Canada and is also commercially important in the Lake States, especially Minnesota. It records a broad band from northern Massachusetts to northern Labrador on the Atlantic coast and west across Canada to the west coast of Alaska. The southern limits are isolated patches in northern New Jersey, western Connecticut, Pennsylvania, southern Michigan, southern Wisconsin, southern Minnesota and southern Manitoba, and the northern limit across Canada and Alaska is about that of the northern tree line, where black spruce alternates with white spruce, tamarack and balsam poplar as the tree-line species. The handbook adds that the commercial range is considerably smaller than the geographic range.

Flowers, cones and growth

Silvics describes black spruce as monoecious, with the female flowers produced in the upper metre of the crown and the male flowers on the outer branches below them. Female flowers are usually erect, cylindrical and green or purplish, and male flowers are dark red to purplish while they expand. A few cones may be produced after 10 years, and the handbook gives the main cone-bearing age as 30 to 250 years, with maximum production between 100 and 200 years. It says stands 80 to 100 years old on the best peatlands and upland sites in southern Canada and the Lake States commonly hold 196 cubic metres per hectare (2,800 cubic feet per acre), and that growth is influenced more by the moisture and aeration regime than by other soil factors.

Roots

The handbook says some black spruce roots may reach 60 cm (24 in) deep, but most spread sideways at the moss and humus layer, with the bulk of the root mass in the upper 20 cm (8 in) of the organic layers. Where organic layers build up fast, several sets of progressively younger roots may develop from the stem, and the new roots may grow as fast as 1 m (3 ft) a year and as much as 4.6 m (15 ft) in 8 to 9 years.

Wood

Silvics describes the wood as yellow-white, relatively light and strong, and says the principal commercial use in Canada and the United States is high quality pulp with balanced strength properties, with lumber, Christmas trees and other products also named. The Wood Handbook (FPL-GTR-282, 2021) lists black, red and white spruce together as eastern spruce, with about the same properties, not distinguished from each other in commerce, and describes the wood as light in colour, easily dried and stable after drying, moderately lightweight, easily worked, and moderately strong, stiff, tough and hard. Silvics also lists historic specialised products from black spruce: healing salves from the resin, beverages from twigs and needles, aromatic distillations from needles, and split roots used as binding for birchbark canoes.

Wood Handbook Table 5-3b	Specific gravity	Modulus of rupture (lbf per square inch)	Side hardness (lbf)
Green	0.38	6,100	340
At 12% moisture content	0.42	10,800	530

The Wood Handbook states that specific gravity is based on oven-dry weight and the volume when green or at 12% moisture content. The green weight of the wood without bark is in the NRS-38 table, the same figure used in the log weight calculator.

Pests and damage the handbook names

Silvics (1990) names these agents by the names it used.

Eastern dwarf mistletoe. Arceuthobium pusillum, called a destructive disease of black spruce in the Lake States and eastern Canada, less common in the West and absent in northwestern Canada and Alaska. The handbook says infection reduces vigour and causes clumped branches (witches' brooms) and deformed trees, and in some stands may kill many trees. The guide mistletoe on the tree covers the mistletoes in general.
Rusts and other diseases. Several Chrysomyxa rusts that infect buds and needles, the cone rust Chrysomyxa pirolata, a needle cast fungus (Lophodermium), the yellow rust witches' broom, and a snow blight (Lophophacidium hyperboreum) that the handbook says can damage nurseries and young regeneration.
Root and stem rots. White pocket rots, most commonly caused by Inonotus tomentosus, which the handbook says may cause significant damage in some upland stands.
Spruce budworm. Choristoneura fumiferana, one of the most damaging insects even though black spruce is less susceptible than red spruce, white spruce and balsam fir. Several years of defoliation in a row may cause moderate to severe mortality.
Other insects. The European spruce sawfly, yellowheaded and greenheaded spruce sawflies, the spruce bud midge, Monochamus wood borers near strip cuts, and the spruce beetle, which the handbook says can invade and kill black spruce growing with white spruce.
Weather, fire and animals. Tops are often broken at 3 to 6 m (10 to 20 ft) by snow and ice, and one storm in Alaska in 1967 and 1968 broke 28 percent of the stems in a 160-year-old stand. The handbook says black spruce is easily killed by ground and crown fires, that peatland stands are sensitive to water-table changes, and that snowshoe hares can damage seedlings and saplings.

The guide on reporting a pest in the United States and the Canada reporting page give the offices that take sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.