SPRUCE

Black spruce (Picea mariana) any of about 40 species of evergreen ornamental and timber trees constituting the genus Picea of the family Pinaceae, native to the temperate and cold regions of the Northern Hemisphere. They are pyramidal trees with whorled branches and thin, scaly bark. Each of the linear, spirally arranged leaves is jointed near the stem on a separate woody base. The base remains as a peglike projection on the twig when the leaf falls. The hanging, persistent-scaled cones are egg-shaped or cylindrical. Resonant spruce wood is used for sounding boards in pianos and the bodies of violins, as well as in construction and for boats and barrels and as pulpwood. Black spruce (Picea mariana) and white spruce (P. glauca) are found throughout most of northern North America, from the Great Lakes to the Arctic tree line. Both are used for pulp; white spruce produces good lumber, and black spruce is the source of spruce gum. White spruce usually is 18 to 21 metres (about 60 to 70 feet) tall. A drought-tolerant variety, Picea glauca Black Hills, is useful in landscaping and in windbreaks. The cones of black spruce are purple, those of white spruce brown. Engelmann spruce (P. engelmanni) of western North America is an important timber source. The blue spruce, or Colorado spruce (P. pungens), has a similar range and is used as an ornamental because of its bluish leaves and symmetrical growth habit. The Norway spruce (P. abies), an important timber and ornamental tree native to northern Europe, is used in reforestation both there and in North America.