Sitka Spruce: State Tree of Alaska

The State tree of Alaska is the Sitka spruce (Picea sitchensis). The Sitka spruce thrives along the Western coastline of the United States from Northern California to Alaska. This pine tree prefers full sun and grows in areas with rich, moist soil. Regions with frequent fog and high rainfall conditions are ideal.

Sitka spruce stand with the giants in the tree world and can attain a mature height above 300 feet. The more likely height is 90-150 feet with a trunk diameter of 3-5 feet. These spruce trees can achieve 700 years of growth.

The sheer weight of the branches causes them to extend downward. It is not unusual to see Sitka spruce branches touching the ground. The branches are covered with short nubs.

The needles are flattened and four-sided making is easier to identify the species. The cones are small, 2-3 1/2 inches, and brown in color. The bark is a deep gray. The bark surface appears broken and covered with scales.

The Sitka spruce is monoecious, having both male and female flowers on the same plant. The male cones are brown. The female cones are green or purple and are found closer to the top of the tree.

The tree seedlings compete for light and nutrients on the forest floor. The successful seedlings often take root on decaying logs where they can grow undisturbed until their roots can reach the soil and reach out to establish a support system that can sustain future growth.

Spruce can be found growing with alders. The alder trees are deciduous and lose their leaves during the winter. The spruce benefit from the extra sunlight. Spruce seedlings also take advantage of soil disturbances, such as glacial melting and forest fires, that clear out competing ground vegetation. The Sitka spruce has been migrating outward along the coastline for 14,000 years, the date of the glacial retreat from the Pacific Northwest.

The Sitka spruce has a straight trunk and is cut for timber. The lumber is considered high grade. The wood pulp can be used to manufacture newsprint. Logging has reduced the original size of the forest spread.

Seeds from the Sitka spruce, and other American trees, were brought to Europe in the 1830s by David Douglas of the Horticulture Society of London. The seedlings did well when planted in poor soils or exposed to wind and salt spray. It can be found in Ireland, Great Britain, New Zealand, Norway, and Iceland.

Sources
The Role of Natural Disturbance in the Range Expansion of Sitka Spruce, by Kaarin Tae, Center for Global Change, University of Alaska Fairbanks, http://www.cgc.uaf.edu/Newsletter/gg5_1/spruce.html
Sitka Spruce, Department of Natural Resources, State of Washington, http://www.dnr.wa.gov/Publications/lm_ess_wog_sitka_spruce.pdf
Sitka Spruce, NearArctic.com, http://www.nearctica.com/trees/conifer/picea/Psitch.htm
Sitka Spruce, Virginia Tech, http://www.cnr.vt.edu/dendro/dendrology/syllabus/factsheet.cfm?ID=223
Sitka Spruce, BorealForest.org, http://www.borealforest.org/world/trees/sitka_spruce.htm
North American Tree Species in Europe, Journal of Forestry, http://sfrc.ifas.ufl.edu/czech/lectures/Forests/hermann_american_trees_in_europe.pdf
Picea sitchensis, Wikipedia, http://en.wikipedia.org/wiki/Picea_sitchensis