Classification and Range
Spruces are part of the pine family of plants, Pinaceae, which includes 200 species throughout the world in northern temperate regions and mountainous tropical regions. Trees in the pine family are generally large or very large and bear pollen and seeds in cones. Most species in the pine family are evergreens with needlelike leaves. Spruces are classified in the genus Picea.
Spruces are found throughout the cooler regions of the Northern Hemisphere. There are approximately 40 species of spruces, half of which are native to China. Only seven species of spruce are native to the United States. Three of these species are found in Alaska: white spruce (Picea glauca), black spruce (Picea mariana) and Sitka spruce (Picea sitchensis).
In Alaska, Sitka spruce grows mainly along the south and southeast coasts together with western hemlock (Tsuga heterophylla). These forests are categorized as temperate coniferous forests. White and black spruce are more characteristic of forests, called boreal forests or taiga, of Alaska’s interior regions, extending north to treeline. White spruce grows more commonly on well drained soils than black spruce, which grows well even in boggy areas
One way to tell spruces from other needle-leafed conifers is to gently close your hand around a sprig of needles-spruce needles are distinctly prickly! Spruce needles are relatively short, spruce bark is scaly, and spruce cones hang down from the branches. Of Alaska’s three spruces, black spruce is generally the smallest and Sitka spruce is the largest, with white spruce falling in the middle.
Although Alaska supports vast areas of both temperate coniferous forests and boreal forests (taiga), logging continues to threaten the integrity of these forests and the ecosystem services they provide, such as erosion prevention, carbon dioxide absorption and oxygen production. Because timber provides valuable economic benefits for Alaska's economy, it is necessary to balance our utilization of this natural resource with the protection of these important ecosystems for future generations.