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State Soil Project:
Help officially recognize Tokul as Washington's State Soil!

Why designate a State Soil?

Washington State’s resources — its people, forests, soils, wildlife, water, and climate make it a GREAT STATE. Washington is noted for its agricultural and forest products, products from its rivers, streams, and bordering ocean, as well as for some of the finest scenery for tourism and outdoor recreation. The resource that is basic to Washington’s greatness is its soil. Washington soils are the basis for food and fiber production for Washingtonians and others worldwide. A “state soil” is represented by a soil series that has special significance to each state. Each state in the United States has selected a state soil, fifteen of which have been legislatively established. Washington’s Tokul Series has not yet been legislatively established.

The “Official State Soil” shares the same level of distinction as the official state flower, state nickname, state bird, state tree, etc. Areas with similar soils are grouped and labeled as soil series because of their similar origins; chemical and physical properties cause soil series to behave similarly for land use purposes. A soil series name is derived from a town, stream, or landmark in or near where the soil series was first recognized. Tokul soils are named after a creek and small community in King County, Washington.

Because Washington State is extremely variable, more than 1,600 soil series are recognized and mapped within the state. Washington soils range from the fertile, deep loess soils of the Palouse Region, to soils pushed up and/or laid down by retreating glaciers, to the soils formed in volcanic ash from the Cascade Volcanoes. Washington recognizes more soils formed in volcanic materials than any other of the 50 states. With this extreme soil variability, how does one select a single soil to represent our great state?

Volcanic ash is the common denominator for all soils in Washington. To some extent, it has influenced soil properties in virtually every soil in the state. Thick deposits of volcanic ash occur in some parts of the state, but even the loess soils of the Columbia Basin and Palouse Region have quantities of volcanic ash mixed into soil profiles. A state soil with properties derived from volcanic ash and that classifies in a special group called “Andisols” therefore represents Washington soils best. (Andisols are soils formed in volcanic ash or materials that weather to similar soil products according to Soil Taxonomy, the international soil classification system used in the United States.)

Tokul soils meet these criteria and are widely mapped within Washington. Tokul soils occur in a large area of the state (about 1,000,000 acres are recognized and mapped in Washington) and this soil also has strong ties to other state symbols. Tokul soils naturally produce evergreen trees (Douglas fir and western hemlock). Washington has been known as the “Evergreen State” since the nickname was adopted by the Legislature in 1893. Western hemlock was adopted as the State Tree by the legislature in 1947.

Profile of Tokul




Counties where Tokul
soils occur




Old growth Douglas-fir
stump on Tokul soils in
King County

Recognizing Tokul Series as the Washington State Soil places emphasis on one of Washington’s most
basic, valuable resources, its soil. It also elevates soil to its proper place among all of Washington’s
other critical resources. Civilizations have risen and fallen based upon their respect for, and
treatment or abuse of, their soil resources.

Let’s officially recognize our soil resources by naming Tokul as the “State Soil” of Washington.

For further information on Tokul and other state soils please follow these links:

List of State Soils from across the country (NRCS)

Smithsonian Soils Exhibit

Washington NRCS Tokul Fact Sheet (.PDF)

Washington State University state soil liaison page

Tokul Poster (.PDF 270 KB)   or click here to request a high resolution (5.5 MEG) PDF of this poster.

Tokul Poster (.JPEG 701 KB)

How you can help:

Contact your WSPSS Area Representatives or Board Members!

To contact us:
Washington Society of Professional Soil Scientists (WSPSS)
P.O. Box 247
Mount Vernon, WA 98273
Contact the Webmaster

Webpage layout designed by WSPSS Member Erik Dahlke

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