Picea mariana

Lore & Background

Picea mariana, the black spruce, is a slow-growing, small upright evergreen conifer, rarely taking a shrub form, with a straight trunk that tapers little, a scruffy appearance, and a narrow, pointed crown made of short, compact, drooping branches whose tips turn upward. Its bark is thin, scaly, and greyish brown. The needle-like leaves are stiff, four-sided, dark bluish green on top and paler glaucous green below. It produces the smallest cones of any spruce, spindle-shaped to nearly round, dark purple ripening to red-brown, which open at maturity but persist for several years in dense clusters in the upper crown. The species ranges across all Canadian provinces and territories, extending into Alaska, the Great Lakes region, and the upper northeastern United States, and is a frequent component of the taiga or boreal forest biome. It is the official tree of Newfoundland and Labrador, where it is the most abundant tree. It naturally hybridizes regularly with red spruce and very rarely with white spruce, from which it differs by having small hairs on the bark of young branch tips, darker reddish-brown bark, shorter needles, smaller rounder cones, and a preference for wetter lowland areas. It also differs from true firs in having pendulous cones, persistent woody leaf-bases, and four-angled needles arranged all around the shoots. The roots are shallow and wide spreading, making it susceptible to windthrow, and in northern areas ice pruning can produce asymmetric trees with diminished foliage on the windward side. Tilted trees known as "drunken trees" are associated with thawing permafrost.

Reader's Guide

Black spruce is ecologically and economically significant across boreal North America. It is the most abundant tree in Newfoundland and Labrador and a key component of the taiga biome. Its timber, though of low value due to small tree size, is an important source of pulpwood in Canada and is increasingly used for cross-laminated timber, as well as for fast-food chopsticks. Along with red spruce, it has been used to make spruce gum and spruce beer. Numerous cultivars have been selected for gardens, including the dwarf form 'Nana', which has gained the Royal Horticultural Society's Award of Garden Merit. The tree's ability to tolerate nutrient-poor, acidic peatlands and its role in post-fire succession make it a vital species in boreal forest ecology. Its natural hybridization with other spruces and its distinctive wood properties—such as the large difference between heartwood and sapwood moisture content, easily distinguished in ultrasound images—add to its scientific interest. The frequent fire return interval perpetuates successional communities, with paper birch and quaking aspen invading burns before black spruce eventually dominates.

Did You Know?

• The Latin specific epithet mariana means 'of the Virgin Mary'.
• Black spruce cones are the smallest of all spruces, measuring 1.5–4 cm long.
• Tilted black spruce trees are colloquially called 'drunken trees' and are associated with thawing permafrost.
• Fast-food chopsticks are often made from black spruce.