Canadian Spruce

Picea glauca, white spruce, is a medium-sized to large evergreen coniferous tree in the Pinaceae (pine family that is widely distributed in the boreal and northern regions of North America. Also known as Canadian spruce, skunk spruce, cat spruce, Black Hills spruce (which is sometimes considered a subspecies, P. glauca subsp. densata, and is the state tree of South Dakota), western white spruce, Alberta white spruce, and Porsild spruce, it is adapted to a wide range of soil and climatic conditions. It is used primarily for pulpwood and as lumber for general construction. White spruce has a straight trunk, reaching heights of 15–26 m (50–85 feet) and diameters of 30–60 cm (12–24 inches). Leaves are needle-shaped but blunt-tipped and stiff, typically 1–2 cm long but can be as short as 0.5 cm, and arranged spirally on the branches. When crushed, the leaves emit a disagreeable odor. Cones are slender and cylindrical, 2.5–5 cm long. In addition to reproducing from seed, vegetative reproduction from layering is common at some sites. Layering is most common in stands in which trees are open grown and the lower branches touch the ground. The branch roots when it is covered by moss, litter, or soil and organic material. Layering probably is an important means of maintaining the stand when sexual reproduction is limited or nonexistent because of climatic limitations. White spruce grows from sea level to about 1520 m (5,000 ft) elevation, with a transcontinental range, from Newfoundland and Labrador west across Canada along the northern limit of trees to Hudson Bay, Northwest Territories, and Yukon. It almost reaches the Arctic Ocean at latitude 69° N. in the District of Mackenzie in the Northwest Territories. In Alaska, it reaches the Bering Sea at Norton Bay and the Gulf of Alaska at Cook Inlet. White spruce is one of the most important commercial species in the boreal forest, commercially harvested for wood fiber and lumber products. The wood, which is light, straight-grained, and resilient, is also used for house logs, musical instruments, paddles, and various boxes and containers. White spruce forests have significant value in maintaining soil stability and watershed values and for recreation. The species is planted as an ornamental and in shelterbelts. Historically, white spruce provided shelter and fuel for both Indians and white settlers of the northern forest. White spruce was the most important species utilized by natives of interior Alaska. The wood was used for fuel, but other parts of the tree also had a purpose; bark was used to cover summer dwellings, roots for lashing birchbark baskets and canoes, and boughs for bedding. Spruce pitch (resin) and extracts from boiled needles were used for medicinal purposes. White spruce in Alaska experienced dramatic declines in the 1990s due to outbreaks of spruce bark beetle (Dendroctonus rufipennis) associated with unusually warm or longer summers, likely associated with global warming. Excerpted and modified from Nienstaedt and Zasada 1994, with additional information from Barnes and Wagner 2004 and Juday 1998.