Spruce

Picea glauca (white spruce) is a species of spruce native to the northern temperate and boreal forests in North America, from central Alaska to as far east as the Avalon Peninsula in Newfoundland, and south to northern Montana, Minnesota, Wisconsin, Michigan, northwestern Pennsylvania, upstate New York, Vermont, New Hampshire, and Maine; there is also an isolated population in the Black Hills of South Dakota and Wyoming.[2][3][4][5][6] It is also known as Canadian spruce, skunk spruce, cat spruce, Black Hills spruce, western white spruce, Alberta white spruce, and Porsild spruce.[7]

The white spruce is a large coniferous evergreen tree which grows normally to 15 to 30 metres (49 to 98 ft) tall, but can grow up to 40 metres (130 ft) tall with a trunk diameter of up to 1 metre (3.3 ft). The bark is thin and scaly, flaking off in small circular plates 5 to 10 centimetres (2.0 to 3.9 in) across. The crown is narrow - conic in young trees, becoming cylindric in older trees. The shoots are pale buff-brown, glabrous (hairless) in the east of the range, but often pubescentin the west, and with prominent pulvini. The leaves are needle-like, 12 to 20 millimetres (0.47 to 0.79 in) long, rhombic in cross-section, glaucous blue-green above with several thin lines of stomata, and blue-white below with two broad bands of stomata.[2][3]

The cones are pendulous, slender, cylindrical, 3 to 7 centimetres (1.2 to 2.8 in) long and 1.5 centimetres (0.59 in) wide when closed, opening to 2.5 centimetres (0.98 in) broad. They have thin, flexible scales 15 millimetres (0.59 in) long, with a smoothly rounded margin. They are green or reddish, maturing to pale brown 4 to 8 months after pollination. The seeds are black, 2 to 3 millimetres (0.079 to 0.118 in) long, with a slender, 5 to 8 millimetres (0.20 to 0.31 in) long pale brown wing.[2][3]

Root system[edit]

The root system of white spruce is highly variable and adaptable (Wagg 1964, 1967),[8][9] responding to a variety of edaphic factors, especially soil moisture, soil fertility, and mechanical impedance. On soils that limit rooting depth, the root system is plate-like, but it is a common misconception to assume that white spruce is genetically constrained to develop plate-like root systems irrespective of soil conditions (Sutton 1969).[10] In the nursery, or naturally in the forest, white spruce usually develops several long “running” roots just below the ground surface (Mullin 1957).[11]