foreword

This soil survey contains information that can be used in land-planning programs

in the Snohomish County Area. It contains predictions of soil behavior for selected

land uses. The survey also highlights limitations and hazards inherent in the soil,

improvements needed to overcome the limitations, and the impact of selected land uses

on the environment.

This soil survey is designed for many different users. Farmers, ranchers,

foresters, and agronomists can use it to evaluate the potential of the soil and the

management needed for maximum food and fiber production. Planners, community

officials, engineers, developers, builders, and home buyers can use the survey to

plan land use, select sites for construction, and identify special practices needed to

insure proper performance. Conservationists, teachers, students, and specialists in

recreation, wildlife management, waste disposal, and pollution control can use the

survey to help them understand, protect, and enhance the environment.

Great differences in soil properties can occur within short distances. Some

soils are seasonally wet or subject to flooding. Some are shallow to bedrock. Some

are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are

poorly suited to use as septic tank absorption fields. A high water table makes a soil

poorly suited to basements or underground installations.

These and many other soil properties that affect land use are described in this

soil survey. Broad areas of soils are shown on the general soil map. The location of each soil

is shown on the detailed soil maps. Each soil in the survey area is described. Information

on specific uses is given for each soil. Help in using this publication and additional

information are available at the local office of the Soil Conservation Service or the

Cooperative Extension Service.

Lynn A. Brown

State Conservationist Soil

Conservation Service

This is a scanned version of the text of the original Soil Survey report of Snohomish County Area, Washington issued July 1983. Original tables

and maps were deleted. There may be references in the text that refer to a table that is not in this document.

Updated tables were generated from the NRCS National Soil Information System (NASIS). The soil map data has been digitized and may include

 some updated information. These are available from http://soildatamart.nrcs.usda.gov. 

Please contact the State Soil Scientist, Natural Resources Conservation Service (formerly Soil Conservation Service) for additional information. 
Location of Snohomish County Area in Washington.
soil survey of

Snohomish County Area,

Washington ______________________ 

By Alfonso Debose and Michael W. Klungland, Soil Conservation Service

Fieldwork by Alfonso Debose, Jonathan P. Edwards, Michael W. Klungland,

George Hartman, Dale E. Snyder, and Barry S. Strickland, Soil Conservation

Service

United States Department of Agriculture, Soil Conservation Service in

cooperation with

Washington State Department of Natural Resources and

Washington State University Agriculture Research Center

SNOHOMISH COUNTY AREA is in the northwestern

part of Washington. It is in Puget Sound Basin. The total area of

Snohomish County Area is 624,640 acres, or about 976 square

miles (20). Everett, the county seat, has a population of

45,100.

The western part of the survey area is nearly level and

rolling, benchlike glaciated plains. The eastern part is very steep

mountains and narrow valleys. The Snohomish-River flows

from southeast to northwest through the center of the area,

and the Stillaguamish River flows from east to west through

the northern part.

Lumbering and dairy farming are the main sources of

income in the area. Wetness limits the area for most other uses.

Specialty crops, row crops, and berries are grown in areas that

are drained and protected from flooding. Commercial fishing is also

an important industry in the area.

The proximity to metropolitan Seattle and the aircraft

manufacturing complexes near Everett have resulted in

increased urbanization of formerly rural areas of Snohomish

County Area. Areas around Everett and Marysville in the westcentral and southwestern parts of the county are the main

parts of the survey area affected by this trend.

Soil scientists have determined that there are about 40

different kinds of soil in the survey area. The soils differ widely

in texture, natural drainage, and other characteristics.

This soil survey updates an earlier survey of Snohomish

County that was published in 1947 (3). It

provides additional information and larger maps that show the

soils in greater detail.

Descriptions, names, and delineations of soils in this

survey do not fully agree with those on soils maps for adjacent

counties. Differences are the result of better knowledge of

soils, modifications in series concepts, intensity of-mapping,

or the extent of soils within the area.

general nature of the survey area

This section provides general information about the survey

area. It discusses history and development,

physiography and drainage, and climate.

history and development

Captain George Vancouver landed near the present site of

Everett, Washington, on July 4, 1792. Native Americans, fur

traders, and trappers were the main inhabitants of the area,

which was dominantly controlled by the Hudson's Bay

Company. A treaty in 1846 made the area part of the United

States, and this opened it to other settlers.

Snohomish County was established on July 14, 1861. Mukilteo

was the county seat. The county seat was moved to Snohomish

in the summer of 1861 and then to Everett in 1892.
The building of the railroad led to the exploitation of timber

resources in the survey area. Tracts along the rivers in the

area were the main sites harvested in these early days of

logging. These low-elevation, warm sites were easily

accessible, had the largest and best timber, and could be

logged most of the year.

The first sawmill began operating at Tulalip in 1853. Other

sawmills were operated at Snohomish, Marysville,

Stanwood, and Lowell in later years. Timber is still the most

important industry in the area.

physiography and drainage

The physiography of the survey area is characterized by:

(1) nearly level alluvial deposits along the major river valleys; (2)

glacial till plains, outwash plains, and terraces in the middle

part of the area; and (3) mountainous areas in the eastern

part of the area.

The basic drainage flow is from the mountains in the east

to the Puget Sound in the west. The North Fork of the

Stillaguamish River, along the northern edge of the survey

area, begins at the town of Darrington and drains into the

Puget Sound. The South Fork, which is in the center of the

area, begins at Granite Falls. and joins the North Fork at the

town of Arlington. The Skykomish River begins at the town

of Index in the southern part of the area, flows westerly through

the towns of Sultan and Monroe, and joins the Snoqualmie

River near the town of Snohomish to form the Snohomish

River. The Snohomish River flows northwesterly through

Everett to the Puget Sound.

climate

Prepared by the National Climatic Center, Asheville, North Carolina.

The climate of Snohomish County Area is greatly tempered

by winds from the Pacific Ocean. Summers are fairly warm, but

hot days are rare. Winters are cool, but snow and freezing

temperatures are not common except at the higher

elevations. During summer, rainfall is extremely light, so

crops growing actively during this period need irrigation.

Several weeks in summer often pass without precipitation.

During the rest of the year, rains are frequent, especially late in

fall and in winter.

Table 1 gives data on temperature and precipitation for

the survey area as recorded at Darrington and Everett for

the period 1951-78. Table 2 shows probable dates of the

first freeze in fall and the last freeze in spring. Table 3 provides

data on length of the growing season.

In winter the average temperatures at Darrington and

Everett are 36 and 40 degrees F, respectively. The average

daily minimum temperature is 30 degrees at Darrington and

34 degrees at Everett. The lowest temperature occurred at

Darrington on January 28, 1969, and is -10 degrees. In

summer the average temperature is 62 degrees at both

Darrington and Everett. The

average daily maximum temperature is about 72 degrees.

The highest recorded temperature, which occurred at

Darrington on July 12, 1951, is 103 degrees.

Growing degree days, shown in table 1, are equivalent to

"heat units." During the month, growing degree days

accumulate by the amount that the average temperature each

day exceeds a base temperature (40 degrees F). The normal

monthly accumulation is used to schedule single or successive

plantings of a crop between the last freeze in spring and

the first freeze in fall.

The total annual precipitation is 83 inches at

Darrington and 36 inches at Everett. Of this, 20 to 30 percent

usually falls in April through September, which includes

the growing season for most crops. The heaviest 1-day

rainfall during the period of record was 6.30 inches at

Darrington on February 28, 1972. Thunderstorms occur

on about 7 days each year, and most occur in summer.

The average seasonal snowfall is 51 inches at Darrington

and 8 inches at Everett. The greatest snow depth at any one

time during the period of record was 44 inches. On an

average, 16 days at Darrington have at least 1 inch of snow on

the ground. Everett seldom has a day with at least 1 inch of

snow on the ground, but the number of such days varies

greatly from year to year.

The average relative humidity in midafternoon is about 60

percent. Humidity is higher at night, and the average at dawn

is about 85 percent. The percentage of possible sunshine is 65

in summer and 25 in winter. The prevailing wind is from the

southwest. Average windspeed is highest, 10 miles per hour, in

winter.

In most winters, one or two storms over the whole area bring

strong and sometimes damaging winds, and in some years the

accompanying heavy rains cause serious flooding. Every few

years, either in winter or in summer, a large invasion of a

continental airmass from the east causes abnormal

temperatures. In winter several consecutive days are well

below freezing; in summer a week or longer is sweltering.

how this survey was made

Soil scientists made this survey to learn what soils are in

the survey area, where they are, and how they can be used. They

observed the steepness, length, and shape of slopes; the

size of streams and the general pattern of drainage; the kinds

of native plants or crops; and the kinds of rock. They dug many

holes to study soil profiles. A profile is the sequence of

natural layers, or horizons, in a soil. It extends from the

surface down into the parent material, which has been

changed very little by leaching or by plant roots.

The soil scientists recorded the characteristics of the

profiles they studied and compared those profiles with

others in nearby counties and in more distant places. They

classified and named the soils according to nationwide uniform

procedures. They drew the
boundaries of the soils on aerial photographs. These

photographs show trees, buildings, fields, roads, and other

details that help in drawing boundaries accurately. The soil maps

at the back of this publication were prepared from aerial

photographs.

The areas shown on a soil map are called map units.

Most map units are made up of one kind of soil. Some are

made up of two or more kinds. The map units in this survey

area are described under "General soil map units" and

"Detailed soil map units."

While a soil survey is in progress, samples of some

soils are taken for laboratory measurements and for

engineering tests. All soils are field tested to determine

their characteristics. Interpretations of those

characteristics may be modified during the survey. Data are

assembled from other sources, such as test results,

records, field experience, and state and local specialists. For

example, data on crop yields under defined management

are assembled from farm records and from field or plot

experiments on the same kinds of soil.

But only part of a soil survey is done when the soils have

been named, described, interpreted, and delineated on aerial

photographs and when the laboratory data and other data

have been assembled. The mass of detailed information then

needs to be organized so that it can be used by farmers,

woodland managers, engineers, planners, developers and

builders, home buyers, and others.
general soil map units

The general soil map at the back of this publication

shows broad areas that have a distinctive pattern of soils,

relief, and drainage. Each map unit on the general soil map

is a unique natural landscape. Typically, a map unit consists

of one or more major soils and some minor soils. It is

named for the major soils. The soils making up one unit

can occur in other units but in a different pattern.

The general soil map can be used to compare the

suitability of large areas for general land uses. Areas of

suitable soils can be identified on the map. Likewise,

areas where the soils are not suitable can be identified.

Because of its small scale, the map is not suitable for

planning the management of a farm or field or for

selecting a site for a road or building or other structure.

The soils in any one map unit differ from place to place in

slope, depth, drainage, and other characteristics that affect

management.

The six map units in this survey are described in the

following pages.

1. Puget-Sultan-Pilchuck

Very deep, poorly drained, moderately well drained, and

somewhat excessively drained, nearly level soils; on flood

plains

This map unit is on flood plains along the major streams

in the northern, central, and southern parts of the survey

area. Slope is 0 to 3 percent. The native vegetation is

mainly conifers and hardwoods. Elevation is 0 to 800 feet.

The average annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free season is 150 to 200 days.

This unit makes up about 11 percent of the survey

area. It is about 35 percent Puget soils, 20 percent

Sultan soils, and 15 percent Pilchuck soils. The

remaining 30, percent is soils of minor extent.

Puget soils are in depressional areas on flood plains.

These soils are very deep and poorly drained. They

formed in alluvium. The soils are silty clay loam to a depth

of 60 inches or more.

Sultan soils are on flood plains. These soils are very

deep and moderately well drained. They formed in

alluvium. The surface layer is silt loam. The next layer is

silty clay loam. Below this to a depth of 60 inches or more

is stratified very fine sandy loam and sand.

Pilchuck soils are on flood plains. These soils are very

deep and somewhat excessively drained. They formed in

alluvium. The surface layer is loamy sand. The

underlying material to a depth of 60 inches or more is

fine sandy loam and fine sand over gravelly sand.

Of minor extent in this unit are well drained Puyallup

soils, poorly drained Snohomish soils, and Sumas soils.

This unit is used mainly as cropland, for hay and

pasture, and for urban development. It is also used for

production of timber, mainly hardwoods.

The main limitation for cultivated crops and for hay

and pasture is the seasonal high water table in areas

that are not adequately drained.

The main limitations for urban development are

seasonal flooding and soil wetness.

2. Norma-Lynnwood-Custer

Very deep, poorly drained and somewhat excessively drained,

nearly level to very steep soils; on outwash plains and

terraces and in basins and depressional areas on outwash plains

and till plains

This map unit is in the north-central part of the survey

area. Slope is 0 to 90 percent. The vegetation is mainly

conifers and hardwoods. Elevation is near sea level to 600

feet. The average annual precipitation is about 40 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free season is 150 to 200 days.

This unit makes up about 6 percent of the survey area. It

is about 40 percent Norma soils, 20 percent Lynnwood soils,

and 10 percent Custer soils. The remaining 30 percent is

soils of minor extent.

Norma soils are in depressional areas on outwash

plains and till plains. These soils are very deep and

poorly drained. They formed in alluvium. The surface

layer is loam. The subsoil and substratum to a depth of

60 inches or more are sandy loam.

Lynnwood soils are on terraces, terrace escarpments,

and outwash plains. These soils are very deep and

somewhat excessively drained. They formed in glacial

outwash. The surface is covered with a mat of leaves,

needles, and twigs. The surface layer and subsoil are

loamy sand. The substratum to a depth of 60 inches or

more is sand.

Custer soils are in basins on outwash plains. These soils

are very deep and poorly drained. They formed in glacial

outwash. The surface layer is fine sandy loam. The upper

part of the subsoil is loamy fine sand, and the lower part is

sand and has a discontinuous, iron-
cemented hardpan. The substratum to a depth of 60

inches or more is fine sand over gravelly coarse sand.

Of minor extent in this unit are Norma Variant soils,

well drained Ragnar soils, and very poorly drained Orcas soils.

This unit is used as cropland and for hay and pasture,

woodland, and urban development.

The main limitation for cultivated crops and for hay

and pasture is the seasonal high water table in areas

that are not adequately drained.

The main limitations of this unit for urban development

are soil wetness, ponding, and steepness of slope. If the

density of housing is moderate to high, community sewage

systems are needed to prevent contamination of water supplies

as a result of seepage from onsite sewage disposal

systems.

3. Alderwood-Everett

Moderately deep and very deep, moderately well drained and

somewhat excessively drained, nearly level to very steep soils;

on till plains, terraces, and outwash plains

This map unit is adjacent to Puget Sound, along the

western edge of the survey area. Slope is 0 to 70 percent.

The vegetation is mainly conifers. Elevation is near sea

level to 550 feet. The average annual precipitation is about

40 inches, the average annual air temperature is about 50

degrees F, and the average frost-free season is 170 to

190 days.

The unit makes up about 37 percent of the survey area.

It is about 60 percent Alderwood soils and 10 percent

Everett soils. The remaining 30 percent is soils of minor

extent.

Alderwood soils are on till plains. These soils are

moderately deep and moderately well drained. They formed

in glacial till. The surface layer is gravelly sandy loam. The subsoil

is very gravelly sandy loam. A weakly cemented hardpan is at a

depth of about 35 inches. Depth to the hardpan ranges

from 20 to 40 inches.

Everett soils are on terraces and outwash plains. These

soils are very deep and somewhat excessively drained. They

formed in glacial outwash. The surface layer is gravelly sandy

loam. The subsoil is very gravelly sandy loam. The substratum

to a depth of 60 inches or more is very gravelly loamy sand over

extremely gravelly sand.

Of minor extent in this unit are moderately well drained

Kitsap soils; poorly drained McKenna, Norma, and Bellingham soils;

very poorly drained Mukilteo soils and Terric Medisaprists; well

drained Ragnar soils; and somewhat excessively drained

Indianola soils.

This unit is used as woodland and for urban

development and hay and pasture.

The main limitations of this unit for urban development are

seasonal soil wetness, depth to the hardpan, and steepness

of slope. If the density of housing is moderate to high,

community sewage systems are needed to prevent

contamination of water supplies as a result of seepage from

onsite sewage disposal systems.

The main limitations for hay and pasture are the depth to

the hardpan and low available water capacity.

4. Tokul-Pastik

Moderately deep and very deep, moderately well drained,

nearly level to very steep soils; on till plains and terraces

This map unit is in the central, northern, and southern

parts of the survey area. Slope is 0 to 50 percent. The

vegetation is mainly conifers. Elevation is 200 to 800 feet.

The average annual precipitation is about 55 inches, the

average annual air temperature is about 46 degrees F, and

the average frost-free season is 140 to 200 days.

This unit makes up about 28 percent of the survey area.

It is about 55 percent Tokul soils and 10 percent Pastik

soils. The remaining 35 percent is soils of minor extent.

Tokul soils are on till plains. These soils are moderately

deep and moderately well drained. They formed in glacial till

and volcanic ash. The surface is covered with a mat of

partially decomposed litter. The surface layer and subsoil are

gravelly loam. The substratum is gravelly fine sandy loam. A

hardpan is at a depth of about 31 inches.

Pastik soils are on terraces. These soils are very deep

and moderately well drained. They formed in lake sediment

and volcanic ash. The soils to a depth of 60 inches or more

are silt loam.

Of minor extent in this unit are Ogarty soils, poorly

drained McKenna soils, very poorly drained Mukilteo

soils and Terric Medisaprists, somewhat excessively

drained Winston soils, and well drained Nargar soils.

This unit is used mainly as woodland. It is also used for

hay and pasture and urban development.

The main limitations for hay and pasture are seasonal soil

wetness, depth to the hardpan, and slope.

The main limitations for urban development are steepness

of slope, wetness, and depth to the hardpan.

5. Elwell-Olomount-Skykomish

Very deep and moderately deep, somewhat excessively drained

and moderately well drained, nearly level to very steep soils; on

mountainsides, ridgetops, terraces, and outwash plains

This map unit is in the mountainous eastern part of the

survey area. Slope is 3 to 90 percent. The vegetation is

mainly conifers. Elevation is 400 to 1,800 feet. The average

annual precipitation is about 70 inches, the average annual

air temperature is about 46 degrees F, and the average

frost-free season is 85 to 150 days.

This unit makes up about 13 percent of the survey

area. It is about 45 percent Elwell soils, 20 percent

Olomount soils, and 15 percent Skykomish soils. The

remaining 20 percent is components of minor extent.

Elwell soils are on mountainsides and ridgetops. These soils

are moderately deep and moderately well
drained. They formed in glacial till and volcanic ash. The

surface is covered with a mat of partially decomposed litter.

The surface layer and subsoil are silt loam. The

substratum is gravelly fine sandy loam. A weakly cemented

hardpan is at a depth of about 27 inches.

Olomount soils are on mountainsides and ridgetops. These

soils are moderately deep and moderately well drained.

They formed in glacial till, volcanic ash, and material derived

from andesite, argillite, and basalt. The surface is covered with

a mat of partially decomposed litter. The surface layer and

subsoil are gravelly loam. The substratum is very gravelly

loam and extremely gravelly loam. Andesite is at a depth of

about 32 inches.

Skykomish soils are on terraces and outwash plains.

These soils are very deep and somewhat excessively drained.

They formed in glacial outwash and volcanic ash. The surface

is covered with a mat of partially decomposed litter. The

surface layer is gravelly loam. The subsoil is gravelly loam and

very gravelly fine sandy loam. The substratum to a depth of 60

inches or more is extremely gravelly loamy coarse sand and

extremely gravelly coarse sand.

Of minor extent-in this, unit are Rober soils, well drained

Nargar Variant soils, and Rock outcrop.

This unit is used mainly as woodland, watershed, and wildlife

habitat.

The main limitation for the harvesting of timber is

seasonal soil wetness and steepness of slope.

6. Getchell-Oso

Moderately deep, moderately well drained, nearly level to

very steep soils; on mountainsides and ridgetops

This map unit is at the mountainous northern and

southern edges of the survey area. Slope is 3 to 90

percent. The vegetation is mainly conifers. Elevation is

1,800 to 2,600 feet. The average annual precipitation is

about 90 inches, the average annual air temperature is

about 43 degrees F, and the average frost-free season is

90 to 125 days.

This unit makes up about 5 percent of the survey area. It is

about 40 percent Getchell soils and 20 percent Oso soils.

The remaining 40 percent is components of minor extent

(fig. 1).

Getchell soils are on mountainsides and ridgetops. These

soils are moderately deep and moderately well drained.

They formed in glacial till and volcanic ash. The surface is

covered with a mat of partially decomposed litter. The

surface layer and subsoil are silt loam. Dense glacial till is at

a depth of about 36 inches.

Oso soils are on mountainsides and ridgetops. These

soils are moderately deep and moderately well drained.

Figure 1.-Typical pattern of soils in the Getchell-Oso general map unit
They formed in glacial till, volcanic ash, and material derived

dominantly from andesite. The surface is covered with a mat

of leaves, needles, twigs, and moss. The soils are gravelly

loam throughout. Andesite is at a depth of about 29

inches.

Of minor extent in this unit are Hartnit, Potchub, and

Verlot soils, very poorly drained Cryohemists, and Rock outcrop.

This unit is used as woodland, watershed, and wildlife

habitat.

The main limitation for the harvesting of timber is

seasonal soil wetness and steepness of slope.

broad land use considerations

The population of Snohomish County Area has increased 21

percent in the last 10 years. This has resulted in increased

demands on the area's natural resources. Each year for the

last 5 years, about 1,000 acres of woodland and pasture has

been converted to urban development. The general soil

map in this survey is helpful for general planning of urban

areas, but it

cannot be used to determine the suitability of a specific

site for a given use.

About 11 percent of the survey area is soils on flood plains.

These soils are mainly in general soil map unit 1. They are severely

limited for urban development, woodland, and most other uses by

the hazards of flooding and ponding. Protection from flooding

and drainage are needed to overcome these limitations. Row

crops and other specialty crops are well suited to these soils

and to some nearly level areas of unit 2 that are on outwash

terraces.

Urban land, consisting of small areas of general soil map

unit 1 and parts of units 3 and 4, makes up about 15 percent

of the area. About 70 percent of the survey area is woodland,

which includes units 5 and 6 and parts of units 3 and 4.

General soil map unit 2 is well suited to parks and other

recreational development. Units 3, 4, 5, and 6 are also suited

to recreation; however, recreational development is not

economically feasible. Trees enhance the beauty of areas of

these units, and the marshes and swamps are suitable for use

as nature study areas. All areas provide habitat for many species of

wildlife.
detailed soil map units

The map units on the detailed soil maps at the back of this

survey represent the soils in the survey area. The map unit

descriptions in this section, along with the soil maps, can be

used to determine the suitability and potential of a soil for

specific uses. They also can be used to plan the

management needed for those uses. More information on

each map unit, or soil, is given under "Use and management

of the soils."

Each map unit on the detailed soil maps represents an area on

the landscape and consists of one or more soils for which the

unit is named.

A symbol identifying the soil precedes the map unit

name in the soil descriptions. Each description includes general

facts about the soil and gives the principal hazards and

limitations to be considered in planning for specific uses.

Soils that have profiles that are almost alike make up a soil

series. Except for differences in texture of the surface layer or

of the underlying material, all the soils of a series have major

horizons that are similar in composition, thickness, and

arrangement.

Soils of one series can differ in texture of the surface

layer or of the underlying material. They also can differ in

slope, stoniness, salinity, wetness, degree of erosion, and

other characteristics that affect their use. On the basis of such

differences, a soil series is divided into soil phases. Most of the

areas shown on the detailed soil maps are phases of soil

series. The name of a soil phase commonly indicates a

feature that affects use or management. For example,

Alderwood gravelly sandy loam, 2 to 8 percent slopes, is one of

several phases in the Alderwood series.

Some map units are made up of two or more major

soils. These map units are called soil complexes.

A soil complex consists of two or more soils in such an

intricate pattern or in such small areas that they cannot be

shown separately on the soil maps. The pattern and

proportion of the soils are somewhat similar in all areas. GetchellOso complex, 15 to 30 percent slopes, is an example.

Most map units include small scattered areas of soils

other than those for which the map unit is named. Some of

these included soils have properties that differ substantially

from those of the major soil or soils. Such differences could

significantly affect use and management of the soils in the

map unit. The included soils are identified in each map unit

description. Some small areas of strongly contrasting soils

are identified by a special symbol on the soil maps.

This survey includes miscellaneous areas. Such areas

have little or no soil material and support little or no

vegetation. Pits is an example. Miscellaneous areas are shown

on the soil maps. Some that are too small to be shown are

identified by a special symbol on the soil maps.

Table 4 gives the acreage and proportionate extent of

each map unit. Other tables (see "Summary of tables") give

properties of the soils and the limitations, capabilities, and

potentials for many uses. The Glossary defines many of the

terms used in describing the soils.

map unit descriptions

1-Alderwood gravelly sandy loam, 2 to 8 percent slopes.

This moderately well drained soil is on till plains. It is moderately

deep over a hardpan. The soil formed in glacial till. Areas are

irregular in shape. They are about 100 acres in size. The native

vegetation is mainly conifers and hardwoods. Elevation is 50 to 550

feet. The average annual precipitation is about 40 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free season is 170 to 190 days.

Typically, the surface layer is very dark grayish brown

gravelly sandy loam about 7 inches thick. The upper part of

the subsoil is dark yellowish brown and dark brown very

gravelly sandy loam about 23 inches thick. The lower part is

olive brown very gravelly sandy loam about 5 inches thick. A

weakly cemented hardpan is at a depth of about 35 inches.

Depth to the hardpan ranges from 20 to 40 inches.

Included in this unit are small areas of soils that have a

stony or bouldery surface layer and areas of McKenna

soils, Norma soils, and Terric Medisaprists in drainageways

on plains. Also included are small areas of Everett,

Indianola, and Ragnar soils on terraces and outwash plains.

Included areas make up about 15 percent of the total

acreage.

Permeability of this Alderwood soil is moderately rapid

above the hardpan and very slow through it. Available water

capacity is low. Effective rooting depth is 20 to 40 inches.

Runoff is slow, and the hazard of water erosion is slight. A

seasonal perched water table is at a depth of 18 to 36

inches from January to March.

This unit is used mainly for urban development and as

woodland. It is also used for hay and pasture.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site
index is 142. On the basis of a 50-year site curve, the mean site

index is 108. The mean annual increment at culmination (CMAI)

for Douglas-fir at age 65 is 148 cubic feet per acre. Among

the trees of limited extent are western redcedar, western

hemlock, and red alder. Among the common forest

understory plants are salal, evergreen huckleberry, Oregongrape, brackenfern, and western swordfern.

This unit is well suited to year-round logging. Logging

roads require suitable surfacing for year-round use. Rock for

road construction is not readily available on this unit, but

gravel is available in areas of adjacent Everett soils. Brush

competition is the main limitation for the production of timber.

Reforestation can be accomplished by planting Douglasfir seedlings. If seed trees are present, natural reforestation of

cutover areas by red alder occurs periodically. When

openings are made in the canopy, invading brushy plants, if

not controlled, can prevent the establishment of seedlings.

Because the rooting depth is restricted by a cemented pan,

trees are subject to windthrow.

This unit is suited to hay and pasture. The main limitations

are the low available water capacity and the weakly

cemented hardpan, which limits the use of the soil in this unit

for deep-rooted plants. Grazing when the soil is wet results in

compaction of the surface layer, poor tilth, and excessive

runoff.

Use of proper stocking rates, pasture rotation, and

restricted grazing during wet periods helps to keep the

pasture in good condition and to protect the soil from erosion.

Periodic mowing and spreading of the droppings help to

maintain uniform growth, discourage selective grazing, and

reduce clumpy growth.

Proper grazing practices and weed control are needed for

maximum quality of forage. In some years, supplemental

irrigation is also needed. Fertilizer is needed for optimum

growth of grasses and legumes.

The main limitations for homesites and septic tank

absorption fields are the depth to the weakly cemented

hardpan and wetness. Drainage needs to be provided if buildings

with basements and crawl spaces are constructed. Onsite

waste disposal systems often fail or do not function properly

during periods of high rainfall. The soil in this unit has an inherent

ability to support large loads. Topsoil needs to be stockpiled during

site preparation and subsequently used to cover the

exposed underlying material.

This map unit is in capability subclass IVe.

2-Alderwood gravelly sandy loam, 8 to 15 percent slopes.

This moderately well drained soil is on till plains. It is moderately

deep over a hardpan. The soil formed in glacial till. Areas are

long and narrow. They are about 125 acres in size. The

native vegetation is mainly conifers and hardwoods. Elevation is

50 to 550 feet. The average annual precipitation is about 40 inches,

the average annual air temperature is about 50 degrees F, and the

average frost-free season is 170 to 190 days.

Typically, the surface layer is very dark grayish brown

gravelly sandy loam about 7 inches thick. The upper part of

the subsoil is dark yellowish brown and dark brown very

gravelly sandy loam about 23 inches thick. The lower part is olive

brown very gravelly sandy loam about 5 inches thick. A weakly

cemented hardpan is at a depth of about 35 inches. Depth to

the hardpan ranges from 20 to 40 inches.

Included in this unit are small areas of Everett, Indianola, and

Kitsap soils on terraces and uplands. Also included are

small areas of Alderwood gravelly sandy loam, 2 to 8

percent slopes. Included areas make up about 15 percent of

the total acreage.

Permeability of this Alderwood soil is moderately rapid

above the hardpan and very slow through it. Available water

capacity is low. Effective rooting depth is 20 to 40 inches. Runoff

is slow, and the hazard of water erosion is slight. A seasonal

perched water table is at a depth of 18 to 36 inches from

January to March.

This unit is used mainly as woodland. It is also used for hay

and pasture and for urban development.

Douglas-fir is the main woodland species on this unit. On the

basis of a 100-year site curve, the mean site index is 142. On

the basis of a 50-year site curve, the mean site index is 108. The

mean annual increment at culmination (CMAI) for Douglas-fir at

age 65 is 148 cubic feet per acre. Among the trees of limited

extent are western redcedar, western hemlock, and red alder.

Among the common forest understory plants are salal, evergreen

huckleberry, Oregon-grape, brackenfern, and western

swordfern.

This unit is well suited to year-round logging. Logging

roads require suitable surfacing for year-round use. Rock for

road construction is not readily available on this unit. Brush

competition is the main limitation for the production of timber.

Reforestation can be accomplished by planting Douglasfir seedlings. If seed trees are present, natural reforestation

of cutover areas by red alder occurs periodically. When

openings are made in the canopy, invading brushy plants, if

not controlled, can prevent the establishment of seedlings.

Because the rooting depth is restricted by a cemented pan,

trees are subject to windthrow.

This unit is suited to hay and pasture. The main limitations

are slope and the weakly cemented hardpan, which limits the use

of the soil in this unit for deep-rooted plants. Grazing when the

soil is wet results in compaction of the surface layer, poor tilth,

and excessive runoff.

Rotation grazing helps to maintain the quality of forage. Use

of proper stocking rates, pasture rotation, and restricted grazing

during wet periods helps to keep the pasture in good condition and

to protect the soil from erosion. Periodic mowing and clipping help to

maintain uniform growth, discourage selective grazing, and

reduce clumpy growth.

Proper grazing practices and weed control are needed for

maximum quality of forage. In some years,
supplemental irrigation is also needed. Fertilizer is

needed for optimum growth of grasses and legumes.

The main limitations for homesites and septic tank

absorption fields are the depth to the weakly cemented

hardpan and wetness because of the seasonal high water

table. Effluent from absorption fields flows laterally above the

hardpan and may seep at the bottom of slopes. Drainage is

needed if buildings with basements and crawl spaces are

constructed. During construction, disturbed areas need to be

seeded and runoff controlled to protect the soil from erosion.

Temporary sediment basins can be used in construction areas to

reduce the amount of sediment in runoff water.

This map unit is in capability subclass IVe.

3-Alderwood gravelly sandy loam, 15 to 25 percent slopes.

This moderately well drained soil is on till plains. It is

moderately deep over a hardpan. The soil formed in glacial till.

Areas are long and narrow, are oriented in a northwest to

southeast direction, and are 20 to 100 acres in size. The

native vegetation is mainly conifers and hardwoods. Elevation is

50 to 550 feet. The average annual precipitation is about 40

inches, the average annual air temperature is about 50

degrees F, and the average frost-free season is 170 to 190

days.

Typically, the surface layer is very dark grayish brown

gravelly sandy loam about 7 inches thick. The upper part of

the subsoil is dark yellowish brown and dark brown very

gravelly sandy loam about 23 inches thick. The lower part is

olive brown very gravelly sandy loam about 5 inches thick. A

weakly cemented hardpan is at a depth of about 35 inches.

Depth to the hardpan ranges from 20 to 40 inches.

Included in this unit are small areas of soils that are similar to

this Alderwood soil but have cobbles or stones on the

surface. Also included are small areas of Everett, Indianola,

and Ragnar soils on terraces and eskers. Included areas

make up about 15 percent of the total acreage.

Permeability of this Alderwood soil is moderately rapid

above the hardpan and very slow through it. Available water

capacity is low. Effective rooting depth is 20 to 40 inches.

Runoff is medium, and the hazard of water erosion is

moderate. A seasonal perched water table is at a depth of 18 to

36 inches from January to March.

This unit is used as woodland and for urban

development.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is 142. On

the basis of a 50-year site curve, the mean site index is

108. The mean annual increment at culmination (CMAI) for

Douglas-fir at age 65 is 148 cubic feet per acre. Among the

trees of limited extent are western redcedar, western

hemlock, and red alder. Among the common forest

understory plants are salal, evergreen huckleberry, Oregongrape, brackenfern, and western swordfern.

This unit is well suited to year-round logging. Logging

roads require suitable surfacing for year-round use. Rock for

road construction is not readily available on this unit.

Reforestation can be accomplished by planting Douglasfir seedlings. If seed trees are present, natural reforestation

of cutover areas by red alder occurs periodically. When

openings are made in the canopy, invading brushy plants, if

not controlled, can prevent the establishment of seedlings.

Because the rooting depth is restricted by a cemented pan,

trees are subject to windthrow.

The main limitations for homesites and septic tank

absorption fields are the steepness of slope, depth to the

weakly cemented hardpan, and wetness because of the seasonal

perched water table. Effluent from absorption fields flows

laterally above the pan and can seep at the bottom of slopes.

Drainage is needed if buildings with basements and crawl

spaces are constructed. During construction, disturbed areas

need to be seeded and runoff controlled to protect the soil from

erosion. Temporary sediment basins can be used to reduce the

amount of sediment in the runoff water. The topsoil needs to

be stockpiled during excavation and subsequently used to cover

the exposed material. A site preparation system that controls

runoff and maintains the esthetic value of the site is needed.

This map unit is in capability subclass IVe.

4-Alderwood-Everett gravelly sandy loams, 25 to 70

percent slopes. This map unit is on till plains, terraces, and

outwash plains. Areas are 30 to 160 acres in size. The

native vegetation is mainly conifers and hardwoods.

Elevation is near sea level to 550 feet. The average annual

precipitation is about 40 inches, the average annual air

temperature is about 50 degrees F, and the average frost-free

season is 170 to 190 days.

This unit is about 60 percent Alderwood gravelly sandy

loam and about 25 percent Everett gravelly sandy loam. The

components of this unit are so intricately intermingled that it

was not practical to map them separately at the scale used.

Included in this unit are small areas of Ragnar, Indianola,

McKenna, and Norma soils and Terric Medisaprists in

depressional areas and drainageways on plains. Also included

are colluvial soils, slump areas, and escarpments. Included

areas make up about 15 percent of the total acreage.

The Alderwood soil is moderately deep over a hardpan and is

moderately well drained. It formed in glacial till. Typically, the

surface layer is very dark grayish brown gravelly sandy loam

about 7 inches thick. The upper part of the subsoil is dark

yellowish brown and dark brown very gravelly sandy loam

about 23 inches thick. The lower part is olive brown very

gravelly sandy loam about 5 inches thick. A weakly

cemented hardpan is at a depth of about 35 inches. Depth

to the hardpan ranges from 20 to 40 inches.

Permeability of the Alderwood soil is moderately rapid

above the hardpan and very slow through it. Available
water capacity is low. Effective rooting depth is 20 to 40

inches. Runoff is rapid, and the hazard of water erosion

is high. A seasonal perched water table is at a depth of 18

to 36 inches from January to March. Springs or seep areas

are common.

The Everett soil is very deep and somewhat excessively

drained. It formed in glacial outwash. Typically, the surface

layer, where mixed to a depth of about 6 inches, is very dark

grayish brown gravelly sandy loam. The subsoil is dark brown

very gravelly sandy loam about 12 inches thick. The upper

part of the substratum is brown very gravelly loamy sand

about 5 inches thick. The lower part to a depth of 60 inches

or more is dark brown extremely gravelly sand.

Permeability of the Everett soil is rapid. Available

water capacity is low. Effective rooting depth is 60 inches or

more. Runoff is rapid, and the hazard of water erosion is

moderate.

This unit is used mainly as woodland and for wildlife

habitat. It is also used for urban development.

Douglas-fir is the main woodland species on the

Alderwood soil. On the basis of a 100-year site curve, the

mean site index is 142. On the basis of a 50-year site curve,

the mean site index is 108. The mean annual increment at

culmination (CMAI) for Douglas-fir at age 65 is 146 cubic feet per

acre.

Douglas-fir is the main woodland species on the Everett

soil. On the basis of a 100-year site curve, the mean site

index is 141. On the basis of a 50-year site curve, the mean

site index is 111. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 65 is 146 cubic feet per acre.

Among the trees of limited extent on this unit are

western hemlock, western redcedar, and red alder. Among

the common forest understory plants are salal, evergreen

huckleberry, brackenfern, red huckleberry, common rose,

and Oregon-grape.

The main limitation for the harvesting of timber is

steepness of slope. Slope restricts the use of wheeled and

tracked equipment in skidding operations; cable yarding

systems generally are safer and disturb the soils less.

Harvesting systems that lift logs entirely off the ground

reduce the disturbance of the protective layer of duff.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is not readily available on this

unit. Establishing plant cover on steep road cut and fill slopes

reduces erosion. Steep yarding paths, skid trails, and firebreaks

are subject to rilling and gullying

unless adequate water bars are provided or they are

protected by plant cover.

Seedling mortality is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs periodically.

The high temperature and low moisture content of the Everett

soil during the growing season cause high mortality of

seedlings, especially

those on south- and southwest-facing slopes. When

openings are made in the canopy, invading brushy plants, if not

controlled, can delay the establishment of seedlings.

Because the rooting depth is restricted by a cemented pan in

the Alderwood soil, trees are subject to windthrow.

The main limitations of the Alderwood soil for septic tank

absorption fields and homesites are steepness of slope and

a seasonal perched water table. Effluent from absorption

fields flows laterally above the pan and can seep at the

bottom of slopes. Drainage is needed if buildings with

basements and crawl spaces are constructed. This soil

sloughs readily when saturated.

The main limitations of the Everett soil for septic tank

absorption fields are steepness of slope and seepage. If the

density of housing is moderate to high, community sewage

systems are needed to prevent contamination of water

supplies as a result of seepage from onsite sewage disposal

systems. Road cuts tend to slough readily.

To protect the soils in this unit from erosion during

construction, disturbed areas need to be seeded and

runoff should be controlled.

This map unit is in capability subclass VIle.

5-Alderwood-Urban land complex, 2 to 8 percent

slopes. This map unit is on till plains. Areas are irregular in

shape and are 100 to 1,000 acres in size. The native

vegetation is mainly conifers. Elevation is 50 to 550 feet. The

average annual precipitation is about 40 inches, the average

annual air temperature is about 50 degrees F, and the

average frost-free season is 170 to 190 days.

This unit is about 60 percent Alderwood gravelly sandy

loam and about 25 percent Urban land. The components of

this unit are so intricately intermingled that it was not

practical to map them separately at the scale used.

Included in this unit are small areas of McKenna and

Norma soils and Terric Medisaprists in depressional areas

and drainageways on plains. Also included are small areas of

soils that are very shallow over a hardpan; small areas of

Everett, Indianola, and Ragnar soils on terraces and

outwash plains; and soils that have a stony and bouldery

surface layer. Included areas make up about 15 percent of

the total acreage.

The Alderwood soil is moderately deep over a hardpan

and is moderately well drained. It formed in glacial till.

Typically, the surface layer is very dark grayish brown

gravelly sandy loam about 7 inches thick. The upper part of

the subsoil is dark yellowish brown and dark brown

very gravelly sandy loam about 23 inches thick. The lower

part is olive brown very gravelly sandy loam about 5 inches

thick. A weakly cemented hardpan is at a depth of about 35

inches. Depth to the hardpan ranges from 20 to 40 inches.

Permeability of the Alderwood soil is moderately rapid

above the hardpan and very slow through it. Available water

capacity is low. Effective rooting depth is 20 to 40 inches.

Runoff is slow, and the hazard of water erosion
is slight. A seasonal perched water table is at a depth of 18

to 36 inches from January to March.

Urban land is areas that are covered by streets,

buildings, parking lots, and other structures that obscure

or alter the soils so that identification is not possible.

The Alderwood soil in this unit is used mainly for

parks, building sites, lawns, gardens, and woodland.

The main limitations of the Alderwood soil for

homesites and septic tank absorption fields are the depth

to the hardpan and the seasonal perched water table. Onsite

waste disposal systems often fail or do not function properly

during periods of high rainfall. Drainage is needed if buildings

with basements and crawl spaces are constructed. Topsoil

needs to be stockpiled during site preparation and

subsequently used to cover the exposed material.

Additions of fertilizer and peat are desirable prior to seeding

grass for lawns.

This map unit is in capability subclass IVe.

6-Alderwood-Urban land complex, 8 to 15 percent

slopes. This map unit is on till plains. Areas are irregular in

shape and are 25 to 100 acres in size. The native vegetation

is mainly conifers and hardwoods. Elevation is 50 to 550 feet.

The average annual precipitation is about 40 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free season is 170 to 190 days.

This unit is about 60 percent Alderwood gravelly sandy loam and

about 25 percent Urban land. The components of this unit

are so intricately intermingled that it was not practical to map

them separately at the scale used.

Included in this unit are small areas of Everett and

Indianola soils on terraces and outwash plains, Kitsap soils on

terraces and terrace escarpments, and Ragnar soils on

outwash plains. Included areas make up about 15 percent

of the total acreage.

The Alderwood soil is moderately deep and moderately

well drained. It formed in glacial till. Typically, the surface layer is

very dark grayish brown gravelly sandy loam about 7

inches thick. The upper part of the subsoil is dark yellowish

brown and dark brown very gravelly sandy loam about 23

inches thick. The lower

part is olive brown very gravelly sandy loam about 5

inches thick. A weakly cemented hardpan is at a depth of

about 35 inches. Depth to the hardpan ranges from 20 to

40 inches.

Permeability of the Alderwood soil is moderately rapid

above the hardpan and very slow through it. Available

water capacity is low. Effective rooting depth is 20 to 40

inches. Runoff is slow, and the hazard of water erosion is

slight. A seasonal perched water table is at a depth of 18 to

36 inches from January to March.

Urban land consists of areas that are covered by streets,

buildings, parking lots, and other structures that obscure or alter

the soils so that identification is not possible.

The Alderwood soil in this unit is used mainly for

parks, building sites, lawns, and woodland.

The main limitations of the Alderwood soil for homesites

and septic tank absorption fields are the depth to the

hardpan and wetness because of the seasonal perched water

table. Drainage is needed if buildings with basements and crawl

spaces are constructed. Onsite sewage disposal systems

often fail or do not function properly during periods of high

rainfall. Topsoil needs to be stockpiled during site preparation

and subsequently used to cover the exposed underlying

material. Additions of fertilizer and peat are desirable

prior to seeding grass for lawns.

This map unit is in capability subclass lVe.

7-Bellingham silty clay loam. This very deep, poorly

drained soil is in depressional areas. It formed in alluvium and

lacustrine sediment. Areas are regular in shape and are about 2

to 25 acres in size. The native vegetation is mainly grass and

sedges. Elevation is 50 to 800 feet. Slope is 0 to 3 percent.

The average annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free season is 160 to 180 days.

Typically, the surface layer is very dark gray silty clay

loam about 9 inches thick. The subsoil to a depth of 60

inches or more is mottled, gray and olive silty clay.

Included in this unit are small areas of Terric Medisaprists,

very poorly drained organic soils, Norma soils along upland

drainageways, Kitsap and Pastik soils on terraces, and

Bellingham soils that have been drained. Included areas

make up about 10 percent of the total acreage.

Permeability of this Bellingham soil is slow. Available

water capacity is high. Effective rooting depth is limited by a

seasonal high water table that is at a depth of 0 to about

12 inches from November to June. Runoff is very slow, and

the hazard of water erosion is slight. Ponding occurs from

November to June.

This unit is used for pasture, woodland, urban

development, and wildlife habitat.

This unit is suited to pasture if the excess water on the

surface is removed. Tile drains or open ditches can be used if

suitable outlets are available. Grazing when the soil in this

unit is wet results in compaction of the surface layer, poor

tilth, and reduced infiltration. Use of proper stocking rates,

pasture rotation, and restricted grazing during wet periods

helps to keep the pasture in good condition. Proper grazing

practices, weed control, and fertilizer are needed for

maximum quality of forage.

This unit is suited to red alder. On the basis of a 50-year

site curve, the mean site index is 83. The mean annual

increment at culmination (CMAI) for red alder at age 40 is

89 cubic feet per acre. Among the trees of limited extent on

this unit are Douglas-fir, bigleaf maple, western redcedar,

and western hemlock. Among the common forest

understory plants are trailing blackberry, western

swordfern, thimbleberry, salmonberry, and huckleberry.

The main limitation for the harvesting of timber is soil

wetness, which limits the use of equipment to dry
periods. Use of wheeled and tracked equipment when

the soil' is wet produces ruts, compacts the soil, and damages

the roots of trees. Unsurfaced roads and skid trails are sticky

when wet and may be impassable during rainy periods. Logging

roads require suitable surfacing for year-round use. Rock for

road construction is not readily available on this unit.

Seedling mortality, brush competition, and the hazard of

windthrow are the main concerns for the production of

timber. If seed trees are present, natural reforestation of

cutover areas by red alder occurs periodically. The seasonal

high water table reduces root respiration, which results in

high seedling mortality. When openings are made in the

canopy, invading brushy plants, if not controlled, can delay

reforestation. Because the rooting depth is restricted by the

silty clay subsoil and the high water table, trees are subject

to windthrow.

The main limitations for homesites are the seasonal

high water table and high shrink-swell potential. If

outlets are available, wetness and ponding can be reduced

by installing drain tile and diverting water away from

buildings. If buildings are constructed on the soil in this unit,

properly designed foundations and footings help to prevent

structural damage as a result of shrinking and swelling.

The main limitations for septic tank absorption

fields are slow permeability and ponding. Onsite waste

disposal systems fail or do not function properly.

This map unit is in capability subclass VIw.

8-Bellingham Variant mucky silty clay loam. This very

deep, poorly drained soil is in drainageways. It formed in

alluvium. Areas are 10 to 40 acres in size. The native

vegetation is mainly conifers. Elevation is 650 to 1,800 feet.

Slope is 0 to 3 percent. The average annual precipitation is

about 60 inches, the average annual air temperature is

about 44 degrees F, and the average frost-free season is

130 to 150 days.

Typically, the surface is covered with a mat of

decomposed grasses, leaves, and roots about 2 inches

thick. The surface layer is very dark grayish brown mucky silty

clay loam about 6 inches thick. The next layers are dark

grayish brown, gray, and greenish gray silty clay loam and silty

clay about 36 inches thick. Below this to a depth of 60

inches or more is greenish gray, stratified loamy fine sand

and silty clay loam. In some areas the surface layer is

silty clay loam.

Included in this unit are areas of Rober soils on mountain

terraces and terrace escarpments and Elwell soils on

mountain slopes and ridgetops. Also included are small

areas of soils that are gravelly silty clay loam throughout.

Included areas make up about 15 percent of the total

acreage.

Permeability of this Bellingham Variant soil is slow. Available

water capacity is high. Effective rooting depth is limited by a

seasonal high water table that is at a depth of 0 to about 12

inches. Runoff is ponded to very slow, and the hazard of

water erosion is slight. Frequent periods of flooding occur

from October to June.

This unit is used as woodland.

Red alder is the main woodland species on this unit. On

the basis of a 50-year site curve, the mean site index is 80.

The mean annual increment at culmination (CMAI) for red

alder at age 40 is 84 cubic feet per acre. Among the trees of

limited extent are western hemlock, western redcedar, and

Sitka spruce. Among the common forest understory plants

are salmonberry, vine maple, red huckleberry,

skunkcabbage, and willow.

The main limitation for the harvesting of timber is

seasonal soil wetness. Frequent ponding and the seasonal

high water table limit the use of equipment when the soil in

this unit is wet. Use of wheeled and tracked equipment

when the soil is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid

trails are sticky when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is not readily

available on this unit.

Seedling mortality, brush competition, and the hazard of

windthrow are the main concerns for the production of

timber. If seed trees are present, natural reforestation of

cutover areas by red alder occurs periodically. A seasonal

high water table reduces root respiration, which results in

high seedling mortality. When openings are made in the

canopy, invading brushy plants, if not controlled, can delay

reforestation. Because the rooting depth is restricted by a

seasonal high water table, trees are occasionally subject to

windthrow.

The main limitations for homesites are the hazard of

flooding, the seasonal high water table, and high shrinkswell potential. If buildings are constructed on the soil in this

unit, properly designing foundations and footings helps to

prevent structural damage as a result of shrinking and

swelling. If outlets are available, wetness and ponding can

be reduced by installing drain tile and diverting water away

from buildings.

The main limitations for septic tank absorption fields are

the hazard of flooding, ponding, and slow permeability.

Onsite sewage disposal systems fail or do not function

properly.

This map unit is in capability subclass VIw.

9-Cathcart loam, 3 to 15 percent slopes. This very

deep, well drained soil is on foothills and mountain foot

slopes. It formed in glacial drift derived from sandstone and

siltstone and in volcanic ash. Areas are 80 to 200 acres in

size. The native vegetation is mainly conifers and

hardwoods. Elevation is 50 to 1,000 feet. The average

annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F,

and the average frost-free season is 165 to 185 days.

Typically, the surface layer is very dark grayish brown

loam about 8 inches thick. The subsoil is dark brown and

yellowish brown loam and sandy loam about 27 inches thick.

The substratum to a depth of 60 inches or more is olive

loam. In some areas the subsoil is sandy clay loam
or clay loam. Weathered siltstone is at a depth of 40 to 60

inches in places.

Included in this unit are small areas of Tokul soils on till

plains and Pastik, Winston, and Ragnar soils on terraces

and outwash plains. Included areas make up about 15

percent of the total acreage.

Permeability of this Cathcart soil is moderate. Available

water capacity is high. Effective rooting depth is 60 inches or

more. Runoff is slow, and the hazard of water erosion is

slight.

This unit is used mainly as woodland. It is also used for

cropland, hay and pasture, and urban development.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is 175.

On the basis of a 50-year site curve, the mean site index is 130.

The mean annual increment at culmination (CMAI) for Douglasfir at age 60 is 186 cubic feet per acre. Among the trees of

limited extent are western hemlock, western redcedar, and

Pacific madrone. Among the common forest understory

plants are western swordfern, trailing blackberry, red

huckleberry, Oregon-grape, and brackenfern.

Reforestation can be accomplished by planting

Douglas-fir seedlings. When openings are made in the

canopy, invading brushy plants, if not controlled, can

prevent reforestation.

The main limitation for the harvesting of timber is seasonal

wetness. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid trails

are soft when wet, and they may be impassable during rainy

periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is not readily available

on this unit.

This unit is suited to use as cropland. A suitable

cropping system is one that includes 1 or 2 years of oats,

3 or 4 years of strawberries, and 5 or 6 years of grasses

and legumes. Continuous cropping with vegetables,

including an annual winter cover crop used as green

manure, is also suitable.

Returning all crop residue to the soil and using a cropping

system that includes grasses, legumes, or grass-legume

mixtures help to maintain fertility and tilth. Compaction of the

soil can be reduced by returning crop residue to the soil and by

proper timing of tillage. Tillage should be on the contour or

across the slope. Crops respond to nitrogen, phosphorus, and

potassium fertilizer.

This unit is suited to hay and pasture. Grazing when the

soil is wet results in compaction of the surface layer, poor

tilth, and excessive runoff. Use of proper stocking rates,

pasture rotation, and restricted grazing during wet periods helps

to keep the pasture in good condition and to protect the soil

from erosion. Periodic mowing and spreading of droppings

help to maintain uniform growth, discourage selective grazing,

and reduce clumpy growth.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. Legumes

benefit from applications of agricultural lime. In some

years supplemental irrigation is also needed.

This unit is suited to urban development. The main

limitation for homesites is steepness of slope. The main

limitations for septic tank absorption fields are moderate

permeability and slopes of more than 8 percent. Absorption

lines should be placed on the contour.

This map unit is in capability subclass Ille.

10-Cathcart loam, 15 to 25 percent slopes. This very

deep, well drained soil is on foothills and mountain foot

slopes. It formed in glacial drift derived from sandstone and

siltstone and in volcanic ash. Areas are 40 to 100 acres in

size. The native vegetation is mainly conifers and

hardwoods. Elevation is 50 to 1,000 feet. The average

annual precipitation is about 45 inches, the average annual

air temperature is about 50 degrees F, and the average

frost-free season is 165 to 185 days.

Typically, the surface layer is very dark grayish brown loam

about 8 inches thick. The subsoil is dark brown and yellowish

brown loam and sandy loam about 27 inches thick. The substratum

to a depth of 60 inches or more is olive loam. In some areas the

subsoil is sandy clay loam or clay loam. Weathered siltstone is

at a depth of 40 to 60 inches in places.

Included in this unit are small areas of Tokul soils on till

plains and Pastik, Winston, and Ragnar soils on terraces and

outwash plains. Included areas make up about 15 percent

of the total acreage.

.Permeability of this Cathcart soil is moderate. Available

water capacity is high. Effective rooting depth is 60 inches or more.

Runoff is medium, and the hazard of water erosion is

moderate.

This unit is used mainly as woodland. It is also used for hay

and pasture and for urban development.

Douglas-fir is the main woodland species on this unit. On the

basis of a 100-year site curve, the mean site index is 175. On

the basis of a 50-year site curve, the mean site index is 130.

The mean annual increment at culmination (CMAI) for

Douglas-fir at age 60 is 186 cubic feet per acre. Among the

trees of limited extent are western hemlock, western redcedar,

and Pacific madrone. Among the common forest understory

plants are western swordfern, trailing blackberry, red

huckleberry, Oregon-grape, and brackenfern.

Reforestation can be accomplished by planting

Douglas-fir seedlings. When openings are made in the

canopy, invading brushy plants, if not controlled, can

prevent reforestation.

The main limitation for the harvesting of timber is seasonal

wetness. Use of wheeled and tracked equipment when the soil

in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid trails are

soft when wet, and they may be impassable during rainy periods.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is not readily available on this unit.

The main limitation for hay and pasture is slope. Fall tillage or

seeding should be on the contour or across the
slope where practical. Grazing when the soil is wet results

in compaction of the surface layer, poor tilth, poor

infiltration, and excessive runoff.

Periodic mowing and spreading of droppings help to maintain

uniform growth and discourage selective grazing. Proper

grazing practices and weed control are needed for

maximum quality of forage. In some years supplemental

irrigation is also needed. Fertilizer is needed for optimum

growth of grasses and legumes. Legumes benefit from

applications of agricultural lime.

The main limitation for homesites and septic tank

absorption fields is steepness of slope.

This map unit is in capability subclass IVe.

11-Cathcart loam, 25 to 50 percent slopes. This very

deep, well drained soil is on foothills and mountain foot

slopes. It formed in glacial drift derived from sandstone and

siltstone and in volcanic ash. Areas are 50 to 200 acres in

size. The native vegetation is mainly conifers and

hardwoods. Elevation is 50 to 1,000 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season in 165 to 185 days.

Typically, the surface layer is very dark grayish brown loam

about 8 inches thick. The subsoil is dark brown and

yellowish brown loam and sandy loam about 27 inches

thick. The substratum to a depth of 60 inches or more is

olive loam. In some areas the subsoil is sandy clay loam or

clay loam. Weathered siltstone is at a depth of 40 to 60

inches in places.

Included in this unit are small areas of Tokul soils on till

plains and Pastik, Winston, and Ragnar soils on terraces and

outwash plains. Included areas make up about 15 percent

of the total acreage.

Permeability of this Cathcart soil is moderate. Available water

capacity is high. Effective rooting depth is 60 inches or

more. Runoff is rapid, and the hazard of water erosion is

high.

This unit is used mainly as woodland.

Douglas-fir is the main woodland species on this unit.

On the basis of a 100-year site curve, the mean site index is

175. On the basis of a 50-year site curve, the mean site

index is 130. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 60 is 186 cubic feet per acre.

Among the trees of limited extent are western hemlock,

western redcedar, and Pacific madrone. Among the common

forest understory plants are western swordfern, trailing

blackberry, red huckleberry, Oregon-grape, and brackenfern.

The main limitation for the harvesting of timber is

steepness of slope, which restricts the use of wheeled and

tracked equipment in skidding operations. Cable yarding

systems generally are safer and disturb the soil less.

Unsurfaced roads and skid trails are soft when wet and

they may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

Establishing plant cover on steep road cut and fill slopes

reduces erosion. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or they are protected by

plant cover.

Brush competition is the main concern for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. When openings are made in the

canopy, invading brushy plants, if not controlled, can prevent

reforestation.

The main limitation for homesites and septic tank

absorption fields is steepness of slope.

This map unit is in capability subclass Vle.

12-Cryohemists, nearly level. These deep, very poorly

drained soils are in depressional areas on high mountain

ridgetops. The soils formed in material derived mainly from

sedges and mosses. Areas are 10 to 30 acres in size. The

native vegetation is mainly sedges and mosses. Elevation is

1,800 to 3,700 feet. Slope is 0 to 1 percent. The average

annual precipitation is about 95 inches, the average annual

air temperature is about 41 degrees F, and the average

frost-free season is 85 to 105 days.

Typically, the upper layer is dark grayish brown and

very dark gray organic material about 10 inches thick.

The next layer is black, very dark grayish brown and dark

reddish brown organic material about 26 inches thick. Below

this is light gray diatomaceous earth about 3 inches thick

over grayish brown and olive gray clay loam that extends to

a depth of 60 inches or more. Texture of the lower layer

varies widely within short distances. Thickness of the

organic material ranges from 16 inches to more than 60

inches.

Included in this unit are small areas of Getchell,

Potchub, and Verlot soils on mountainsides and

ridgetops. Included areas make up about 15. percent of the

total acreage.

Permeability of these Cryohemists is moderately slow.

Available water capacity is high. Effective rooting depth is

limited by a seasonal water table that is at a depth of 0 to

about 10 inches. Runoff is ponded.

This unit is used mainly for wetland wildlife habitat. It

provides nesting areas for ducks, heron, and other

waterfowl. Plantings of smartweed, wild millet, or

bullrush encourage added populations. This unit also

provides habitat for muskrats and beavers. Logging in the

area may disturb the value of the unit as nesting areas for

waterfowl.

This map unit is in capability subclass Vw.

13-Custer fine sandy loam. This very deep, poorly

drained soil is in basins on outwash plains. It formed in

glacial outwash. Areas are 15 to 40 acres in size. The

native vegetation is mainly conifers and hardwoods.

Elevation is near sea level to 150 feet. Slope is 0 to 2

percent. The average annual precipitation is about 40

inches, the average annual air temperature is about 50
degrees F, and the average frost-free season is 150 to

200 days.

Typically, the surface layer is very dark grayish brown fine

sandy loam about 9 inches thick. The upper part of the

subsoil is loamy fine sand about 7 inches thick. The lower

part is gray and olive sand about 19 inches thick and has

iron-cemented concretions that form a discontinuous

hardpan. The substratum is gray sand about 14 inches thick

over gravelly coarse sand that extends to a depth of 60

inches or more. In some areas a hardpan is not present in

the subsoil.

Included in this unit are small areas of Indianola soils on

terraces, Norma soils in upland drainageways, and Custer soils

that have been partially drained. Included areas make up

about 15 percent of the total acreage.

Permeability of this Custer soil is moderately slow in

the discontinuous hardpan and very rapid below it.

Available water capacity is low. Effective rooting depth is

limited by a seasonal high water table that is at a depth of

about 12 inches. Runoff is very slow. Ponding occurs from

November to March.

This unit is used mainly for pasture and as cropland. A

few areas are used as woodland.

The main limitation for pasture is wetness. Grazing when the

soil in this unit is wet results in compaction of the surface

layer. Use of proper stocking rates, pasture rotation, and

restricted grazing during wet periods helps to keep the

pasture in good condition and protects the soil from

erosion. Periodic mowing and spreading of droppings help

to maintain uniform growth and discourage selective grazing.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. Fertilizer is

needed for optimum growth of grasses and legumes.

The depth to the water table is the main limitation of the

soil in this unit for crops such as strawberries. Open

ditches and tile drains help to remove excess water.

Chiseling or subsoiling may be needed to improve permeability

and increase rooting depth. Crops may require supplemental

irrigation during the growing season. The organic matter

content can be maintained by using all crop residue,

plowing under green manure crops, and using a suitable

cropping system.

This unit is suited to use as woodland. On the basis of a

50-year site curve, the estimated mean site index for red

alder is 90. The estimated mean annual increment at

culmination (CMAI) for red alder at 40 years of age is 101

cubic feet per acre.

The main limitation for the harvesting of timber is

wetness. The seasonal high water table limits the use of

equipment when the soil in this unit is wet. Use of wheeled

and tracked equipment when the soil is wet produces ruts,

compacts the soil, and damages the roots of trees.

Unsurfaced roads and skid trails are soft when wet, and they

may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

The establishment of seedlings is the main concern in the

production of timber. The seasonal high water table and

ponding reduce root respiration, which results in high

seedling mortality. If seed trees are present, natural

reforestation of cutover areas by red alder occurs rapidly.

Western redcedar may also be suitable for reforestation.

Because the rooting depth is restricted by the discontinuous

hardpan and the seasonal high water table, trees are subject

to windthrow. When openings are made in the canopy,

invading brushy plants, if not controlled, can delay

reforestation.

The main limitation for homesites is the seasonal high

water table. Wetness can be reduced by installing drain tile

around footings. The main limitations for septic tank

absorption fields are ponding, wetness, and moderately slow

permeability. If effluent penetrates below the discontinuous

hardpan, seepage into the water table is also a limitation.

Cutbanks on this unit are subject to caving in.

This map unit is in capability subclass IVw.

14-Elwell silt loam, 3 to 30 percent slopes. This

moderately deep, moderately well drained soil is on

mountainsides and ridgetops. It formed in glacial till and

volcanic ash. Areas are 20 to 50 acres in size. The native

vegetation is mainly conifers. Elevation is 800 to 1,800 feet.

The average annual precipitation is about 70 inches, the

average annual air temperature is about 45 degrees F, and

the average frost-free season is 130 to 150 days.

Typically, the surface layer is black silt loam about 2

inches thick. The subsoil is strong brown, brown, and

yellowish brown silt loam about 21 inches thick. The

substratum is pale olive gravelly fine sandy loam about 4

inches thick. An olive, weakly cemented hardpan is at a

depth of about 27 inches. Depth to the hardpan ranges from

20 to 40 inches. In some areas the hardpan is at a depth of

more than 40 inches.

Included in this unit are small areas of Rober and

Olomount soils on mountainsides and ridgetops and

Skykomish soils on terraces. Included areas make up

about 15 percent of the total acreage.

Permeability of this Elwell soil is moderate to the hardpan

and very slow through it. Available water capacity is

moderate. Effective rooting depth is 20 to 40 inches. A

seasonal perched water table is at a depth of 18 to 36

inches from November to June. Runoff is slow, and the

hazard of water erosion is slight.

This unit is used mainly as woodland, watershed, and

wildlife habitat.

Western hemlock is the main woodland species on this

unit. On the basis of a 100-year site curve, the mean site

index is 152. On the basis of a 50-year site curve, the mean

site index is 108. The mean annual increment at culmination

(CMAI) for western hemlock at age 50 is 241 cubic feet per

acre. Among the trees of limited extent are Douglas-fir,

western redcedar, Pacific silver fir, red alder, and bigleaf

maple. Among the common forest
understory plants are western swordfern, red

huckleberry, brackenfern, deer fern, and salal.

The main limitation for the harvesting of timber is

seasonal soil wetness. Occasional snowpack hinders

harvesting operations. The seasonal perched water table limits the

use of equipment to dry periods. Use of wheeled and

tracked equipment when the soil is wet produces ruts,

compacts the soil, and damages the roots of trees.

Disturbance of the protective layer of duff can be reduced

with the careful use of wheeled and tracked equipment.

Unsurfaced roads and skid trails are soft when wet, and

they may be impassable during rainy periods. Rock for road

construction is not readily available on this unit. Establishing

plant cover on steep road cut and fill slopes reduces erosion.

Seedling establishment and the hazard of windthrow are the

main concerns in the production of timber. If seed trees are

present, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically.

Reforestation can be accomplished by planting Douglas-fir

seedlings. When openings are made in the canopy, invading

brushy plants, if not controlled, can delay reforestation.

Because the rooting depth is restricted by a compacted

layer of till, trees are subject to windthrow. Western

hemlock, a shallow-rooted species, is more commonly

subject to windthrow than are more deeply rooted

trees.

The main limitations for homesites are the seasonal

perched water table and steepness of slope in areas where

slope is more than 15 percent. Drainage is needed if

buildings with basements and crawl spaces are constructed.

The main limitations for septic tank absorption fields are

the depth to the hardpan, the seasonal perched water

table, and steepness of slope in areas where slope is

more than 15 percent.

This map unit is in capability subclass IVe.

15-Elwell-Olomount complex, 15 to 30 percent

slopes. This map unit is on mountainsides and ridgetops.

Areas are 100 to 400 acres in size. The native vegetation is

mainly conifers. Elevation is 800 to 1,800 feet. The average

annual precipitation is about 70 inches, the average annual

air temperature is about 44 degrees F, and the average

frost-free season is 130 to 150 days.

This unit is about 65 percent Elwell silt loam and about 20

percent Olomount gravelly loam. The components of this unit

are so intricately intermingled that it was not practical to

map them separately at the scale used.

Included in this unit are small areas of Rober soils on

terraces and terrace escarpments, Skykomish soils on

terraces and outwash plains, soils that have a hardpan at a

depth of more than 40 inches, and Rock outcrop. Included

areas make up about 15 percent of the total acreage.

The Elwell soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface layer is black silt loam about 2 inches thick. The

subsoil is strong brown, brown, and yellowish brown silt loam

about 21 inches thick. The substratum is pale olive gravelly

fine sandy loam about 4 inches thick. An olive, weakly

cemented hardpan is at a depth of about 27 inches. Depth to

the hardpan ranges from 20 to 40 inches.

Permeability of the Elwell soil is moderate to the hardpan

and very slow through it. Available water capacity is

moderate. Effective rooting depth is 20 to 40 inches. Runoff

is rapid, and the hazard of water erosion is high. A seasonal

perched water table is at a depth of 18 to 36 inches from

November to June.

The Olomount soil is moderately deep and moderately

well drained. It formed in glacial till, volcanic ash, and

material derived dominantly from andesite, argillite, and

basalt. Typically, the surface is covered with a mat of leaves,

needles, mosses, and partially decomposed litter about 3

inches thick. The surface layer is very dark grayish brown

gravelly loam about 2 inches thick. The subsoil is reddish

brown and dark brown gravelly loam about 16 inches thick.

The substratum is dark brown very gravelly loam and

extremely gravelly loam about 14 inches thick. Andesite is at

a depth of about 32 inches. Depth to andesite ranges from

20 to 40 inches.

Permeability of the Olomount soil is moderate. Available

water capacity is low. Effective rooting depth is 20 to 40

inches. Runoff is rapid, and the hazard of water erosion is

high. A seasonal perched water table is at a depth of 18 to

36 inches from November to May.

This unit is used mainly as woodland, watershed, and

wildlife habitat.

Western hemlock is the main woodland species on the

Elwell soil. On the basis of a 100-year site curve, the mean

site index is 152. On the basis of a 50-year site curve, the

mean site index is 108. The mean annual increment at

culmination (CMAI) for western hemlock at age 50 is 241

cubic feet per acre.

Western hemlock is also the main woodland species on

the Olomount soil. On the basis of a 100-year site curve, the

mean site index is 152. On the basis of a 50-year site

curve, the mean site index is 112. The mean annual

increment at culmination (CMAI) for western hemlock is at

age 50 is 241 cubic feet per acre.

Among the trees of limited extent on this unit are

Douglas-fir, western redcedar, Pacific silver fir, red alder, and

bigleaf maple. The common forest understory plants are

brackenfern, vine maple, deer fern, salmonberry, salal,

western swordfern, and red huckleberry.

The main limitation for the harvesting of timber is seasonal

soil wetness. Occasional snowpack hinders harvesting

operations. Disturbance of the protective layer of duff can be

reduced with the careful use of wheeled and tracked

equipment. The seasonal perched water table limits the use

of equipment to dry periods. Use of wheeled and tracked

equipment when the soils in this
unit are wet produces ruts, compacts the soils, and

damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable

surfacing for year-round use. Rock for road construction is

readily available on this unit. Establishing plant cover on

steep road cut and fill slopes reduces erosion.

Seedling establishment and windthrow hazard are the

main concerns in the production of timber. If seed trees

are present, natural reforestation of cutover areas by

western hemlock and Pacific silver fir occurs periodically.

Reforestation can be accomplished by planting Douglas-fir

seedlings. When openings are made in the canopy,

invading brushy plants, if not controlled, can delay

reforestation.

Because the rooting depth is restricted by the hardpan or

bedrock, trees are occasionally subject to windthrow.

Western hemlock, a shallow- rooted species, is more

commonly subject to windthrow than are more deeply

rooted trees.

The main limitations for homesites and septic tank

absorption fields are steepness of slope, depth to bedrock

or the hardpan, and wetness. A seasonal high water table

is perched above the hardpan or bedrock; therefore,

drainage is needed if buildings with basements and crawl

spaces are constructed. Deep cuts in the Olomount soil can

expose bedrock.

This map unit is in capability subclass IVe.

16-Elwell-Olomount-Rock outcrop complex, 30 to 60

percent slopes. This map unit is on mountainsides. Areas

are 100 to 400 acres in size. The native vegetation is

mainly conifers. Elevation is 800 to 1,800 feet. The average

annual precipitation is about 70 inches, the average annual

air temperature is about 44 degrees F, and the average

frost-free season is 130 to 150 days.

This unit is about 50 percent Elwell silt loam, about 25

percent Olomount gravelly loam, and about 10 percent

Rock outcrop. The components of this unit are so

intricately intermingled that it was not practical to map them

separately at the scale used.

Included in this unit are small areas of Rober soils on

terraces and terrace escarpments, Skykomish soils on

terraces and outwash plains, and talus slopes below areas

of Rock outcrop. Included areas make up about 15 percent

of the total acreage.

The Elwell soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface layer is black silt loam about 2 inches thick. The

subsoil is strong brown, brown, and yellowish brown silt

loam about 21 inches thick. The substratum is pale olive

gravelly fine sandy loam about 4 inches thick. An olive,

weakly cemented hardpan is at a depth of about 27

inches. Depth to the hardpan ranges from 20 to 40 inches.

Permeability of the Elwell soil is moderate to the

hardpan and very slow through it. Available water

capacity is moderate. Effective rooting depth is 20 to 40

inches. Runoff is rapid, and the hazard of water erosion is

high. A seasonal perched water table is at a depth of 18 to

36 inches from November to June.

The Olomount soil is moderately deep and moderately

well drained. It formed in glacial till, volcanic ash, and

material derived dominantly from andesite, argillite, and

basalt. Typically, the surface is covered with a mat of

leaves, needles, mosses, and partially decomposed litter

about 3 inches thick. The surface layer is very dark grayish

brown gravelly loam about 2 inches thick. The subsoil is

reddish brown and dark brown gravelly loam about 16

inches thick. The substratum is dark brown very gravelly

loam and extremely gravelly loam about 14 inches thick.

Andesite is at a depth of about 32 inches. Depth to

andesite ranges from 20 to 40 inches.

Permeability of the Olomount soil is moderate. Available

water capacity is low. Effective rooting depth is 20 to 40

inches. Runoff is rapid, and the hazard of water erosion is

high. A seasonal perched water table is at a depth of 18 to

36 inches from November to May.

Rock outcrop consists of areas where 90 percent of the

surface is exposed, unweathered andesite, argillite, or

basalt.

This unit is used mainly as woodland, watershed, and

wildlife habitat.

Western hemlock is the main woodland species on the

Elwell soil. On the basis of a 100-year site curve, the mean

site index is 152. On the basis of a 50-year site curve, the

mean site index is 108. The mean annual increment at

culmination (CMAI) for western hemlock at age 50 is 241

cubic feet per acre.

Western hemlock is also the main woodland species on

the Olomount soil. On the basis of a 100-year site curve,

the mean site index is 152. On the basis of a 50-year site

curve, the mean site index is 115. The mean annual

increment at culmination (CMAI) for western hemlock at

age 50 is 241 cubic feet per acre.

The areas of Rock outcrop in this unit reduce yield by

about 10 percent.

Among the trees of limited extent on this unit are

Douglas-fir, western redcedar, Pacific silver fir, red alder,

and bigleaf maple. Among the common forest understory

plants are brackenfern, vine maple, deer fern, salmonberry,

and salal.

The main limitations for the harvesting of timber are

steepness of slope, Rock outcrop, and seasonal soil

wetness. A seasonal perched water table limits the use of

equipment. Areas of Rock outcrop and occasional

snowpack hinder harvesting operations. When harvesting

timber, steepness of slope restricts the use of wheeled and

tracked equipment in skidding operations; cable yarding

systems generally are safer and disturb the soils less.

Unsurfaced roads and skid trails are soft when wet,

and they may be impassable during rainy periods.

Logging roads require suitable surfacing for year-round

use. Rock for road construction is readily available on
this unit. Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars are

provided or they are protected by plant cover. Establishing

plant cover on steep cut and fill slopes reduces erosion.

Seedling establishment and windthrow hazard are the

main concerns in the production of timber. If seed trees are

present, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. Reforestation

can be accomplished by planting Douglas-fir seedlings.

When openings are made in the canopy, invading brushy

plants, if not controlled, can delay reforestation. Rock

outcrop limits the even distribution of reforestation.

Because the rooting depth is restricted by the hardpan or

bedrock, trees are occasionally subject to windthrow.

Western hemlock, a shallow-rooted species, is more

commonly subject to windthrow than are more deeply

rooted trees.

The main limitations for homesites and septic tank

absorption fields are steepness of slope and depth to

bedrock or the hardpan. A seasonal high water table is

perched above the hardpan or bedrock; therefore, drainage is

needed if buildings with basements and crawl spaces are

constructed. Deep cuts in-the Olomount soil can expose

bedrock.

This map unit is in capability subclass Vlls.

17-Everett gravelly sandy loam, 0 to 8 percent

slopes. This very deep, somewhat excessively drained soil is on

terraces and outwash plains. It formed in glacial outwash.

Areas are long and narrow and are oriented in a northwest to

southeast direction. They are 10 to 40 acres in size. The

native vegetation is mainly conifers. Elevation is near sea

level to 500 feet. The average annual precipitation is

about 40 inches, the average annual air temperature is

about 50 degrees F, and the average frost-free season is

170 to 190 days.

Typically, the surface layer, where mixed to a depth of about 6

inches, is dark brown gravelly sandy loam. The subsoil is dark

brown very gravelly sandy loam about 12 inches thick. The

upper part of the substratum is brown very gravelly loamy sand

about 5 inches thick. The lower part to a depth of 60 inches or

more is dark brown extremely gravelly sand. In some areas the

substratum is weakly cemented.

Included in this unit are small areas of Alderwood soils on

till plains, Indianola soils on terraces and outwash plains,

and Ragnar soils on outwash plains. Included areas make

up about 15 percent of the total acreage.

Permeability of this Everett soil is rapid. Available water

capacity is low. Effective rooting depth is 60 inches or

more. Runoff is slow, and the hazard of water erosion is

slight.

This unit is used mainly as woodland and for urban

development. It is also used for pasture.

Douglas-fir is the main woodland species on this unit.

On the basis of a 100-year site curve, the mean site

index is 141. On the basis of a 50-year site curve, the mean

site index is 111. The mean annual increment at

culmination (CMAI) for Douglas-fir at age 65 is 146 cubic

feet per acre. Among the trees of limited extent are western

hemlock, western redcedar, and red alder. The common

forest understory plants are salal, brackenfern, red

huckleberry, common rose, and Oregon-grape.

This unit is well suited to year-round logging. Logging

roads require suitable surfacing for year-round use. Rock for road

construction is readily available on this unit.

Seedling mortality is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. High soil temperature and low soil

moisture content during the growing season cause a high

mortality of seedlings. When openings are made in the

canopy, invading brushy plants, if not controlled, can delay

the establishment of seedlings.

If this unit is used for pasture, the main limitations are low

available water capacity and low soil fertility. Proper

grazing practices, weed control, and fertilizer are needed for

maximum quality of forage. Supplemental irrigation is

also needed. Periodic mowing and spreading of droppings

help to maintain uniform growth and discourage selective

grazing.

This unit is suited to urban development; however, if the

density of housing is moderate to high, community

sewage systems are needed in places to prevent

contamination of water supplies as a result of seepage

from onsite sewage disposal systems.

This map unit is in capability subclass VIs.

18-Everett gravelly sandy loam, 8 to 15 percent

slopes. This very deep, somewhat excessively drained soil is

on terraces and outwash plains. It formed in glacial

outwash. Areas are long and narrow and are oriented in

a northwest to southeast direction. They are 10 to 40 acres

in size. The native vegetation is mainly conifers. Elevation

is near sea level to 500 feet. The average annual

precipitation is about 40 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 170 to 190 days.

Typically, the surface layer, where mixed to a depth of

about 6 inches, is dark brown gravelly sandy loam. The

subsoil is dark brown very gravelly sandy loam about 12

inches thick. The upper part of the substratum is brown very

gravelly loamy sand about 5 inches thick. The lower part to

a depth of 60 inches or more is dark brown extremely

gravelly sand. In some areas the substratum is weakly

cemented.

Included in this unit are small areas of Alderwood soils on

till plains, Indianola soils on terraces and outwash plains,

and Ragnar soils on outwash plains. Included areas make

up about 15 percent of the total acreage.

Permeability of this Everett soil is rapid. Available water

capacity is low. Effective rooting depth is 60 inches or

more. Runoff is slow, and the hazard of water erosion is

slight.

This unit is used mainly as woodland. It is also used for

urban development and for hay and pasture.
Douglas-fir is the main woodland species on this unit. On the

basis of a 100-year site curve, the mean site index is 141.

On the basis of a 50-year site curve, the mean site index is

111. The mean annual increment at culmination (CMAI) for

Douglas-fir at age 65 is 146 cubic feet per acre. Among the trees

of limited extent are western hemlock, western redcedar, and red

alder. The common forest understory plants are salal,

brackenfern, red huckleberry, common rose, and Oregongrape.

This unit is well suited to year-round logging. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is readily available on this unit.

Seedling mortality is the main limitation in the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. High soil temperature and low soil

moisture content during the growing season cause a high

mortality of seedlings. When openings are made in the

canopy, invading brushy plants, if not controlled, can delay the

establishment of seedlings.

If this unit is used for hay and pasture, the main limitations

are slope, low available water capacity, and low soil fertility.

Rotation grazing, proper stocking rates, weed control, and

fertilizer are needed for maximum quality of forage.

Supplemental irrigation is also needed. Periodic mowing and

spreading of droppings help to maintain uniform growth and

discourage selective grazing. Fertilizer is needed for optimum

growth.

The main limitation for homesites and septic tank

absorption fields is steepness of slope. If the density of

housing is moderate to high, community sewage systems may be

needed to prevent contamination of water supplies as a

result of seepage. Septic tank absorption lines should be

installed on the contour.

This map unit is in capability subclass Vls.

19-Everett gravelly sandy loam, 15 to 25 percent

slopes. This very deep, somewhat excessively drained soil is on

terraces and outwash plains. It formed in glacial outwash.

Areas are irregular in shape and are 10 to 40 acres in size. The

native vegetation is mainly conifers. Elevation is near sea

level to 500 feet. The average annual precipitation is about

40 inches, the average annual air temperature is about 50

degrees F, and the average frost-free season is 170 to 190

days.

Typically, the surface layer, where mixed to a depth of

about 6 inches, is dark brown gravelly sandy loam. The subsoil is

dark brown very gravelly sandy loam about 12 inches thick. The

upper part of the substratum is brown very gravelly loamy

sand about 5 inches thick. The lower part to a depth of 60

inches or more is dark brown extremely gravelly sand. In some

areas the substratum is weakly cemented.

Included in this unit are small areas of Alderwood soils on

till plains, Indianola soils on terraces and outwash plains, and

Ragnar soils on outwash plains. Included areas make up

about 15 percent of the total acreage.

Permeability of this Everett soil is rapid. Available

water capacity is low. Effective rooting depth is 60

inches or more. Runoff is medium, and the hazard of

water erosion is moderate.

This unit is used mainly as woodland. It is also used for

urban development.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

141. On the basis of a 50-year site curve, the mean site

index is 111. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 65 is 146 cubic feet per acre.

Among the trees of limited extent are western hemlock,

western redcedar, and red alder. The common forest

understory plants are salal, brackenfern, red huckleberry,

common rose, and Oregon-grape.

This unit is well suited to year-round logging. Logging

roads require suitable surfacing for year-round use. Rock

for road construction is readily available on this unit.

Establishing plant cover on steep road cut and fill slopes

reduces erosion.

Seedling mortality is the main limitation in the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. High soil temperature and low soil

moisture content during the growing season cause a high

mortality of seedlings, especially on south- and southwestfacing slopes. When openings are made in the canopy,

invading brushy plants, if not controlled, can delay the

establishment of seedlings, especially on south- and

southwest-facing slopes.

The main limitation for homesites and septic tank

absorption fields is steepness of slope. If the density of

housing is moderate or high, community sewage systems

are needed to prevent contamination of water supplies as a

result of seepage from onsite sewage disposal systems.

This map unit is in capability subclass IVe.

20-Fluvaquents, tidal. These very deep, poorly drained,

salt-affected soils are on tidal flats. They formed in alluvium.

Areas are 30 to 200 acres in size. The native vegetation is

mainly saltgrass. Elevation is near sea level to 10 feet. Slope

is 0 to 2 percent. The average annual precipitation is about

30 inches, the average annual air temperature is about 52

degrees F, and the average frost-free season is 190 to 210

days.

These soils to a depth of 60 inches or more commonly are

gray and light gray, stratified silt loam and silty clay loam.

They range from sand to clay throughout the profile and vary

widely within short distances. In some places these soils

have strata of organic matter and clam shells.

Included in this unit are small areas of Mukilteo and Puget

soils and Terric Medisaprists in depressional areas. Also

included are several hundred acres of soils that have been

diked, drained, and leached for seed crops and areas that

have been diked and used as industrial sites. Included

areas make up about 5 percent of the total acreage.

Permeability of Fluvaquents, tidal, is slow. Available

water capacity is high. Effective rooting depth is limited
to a depth of 10 to 20 inches. Water covers these soils

during high tide. Runoff is ponded.

This unit is used mainly for recreation and wildlife habitat.

Clam digging and waterfowl hunting are the main

recreational activities on the unit. Waterfowl such as herons

and ducks use the unit as feeding and nesting areas.

This map unit is in capability subclass VIIw.

21-Getchell silt loam, 3 to 30 percent slopes. This

moderately deep, moderately well drained soil is on

mountainsides and ridgetops. It formed in glacial till and

volcanic ash. Areas are irregular in shape and are 30 to 60 acres

in size. The native vegetation is mainly conifers. Elevation is

1,800 to 2,600 feet. The average annual precipitation is

about 90 inches, the average annual air temperature is

about 43 degrees F, and the average frost-free season is

105 to 125 days.

Typically, the surface is covered with a mat of needles,

leaves, twigs, and decomposed material about 2 inches thick.

The surface layer is black silt loam about 2 inches thick. The

subsoil is yellowish red, strong brown, light olive brown, and

dark brown silt loam about 34 inches thick. Olive, dense

glacial till is at a depth of about 36 inches. Depth to glacial till

ranges from 20 to 40 inches.

Included in this unit are small areas of wet organic soils.

Also included are Elwell, Olomount, and Potchub soils.

Included areas make up about 15 percent of the total

acreage.

Permeability of this Getchell soil is moderate to the dense

glacial till and very slow through it. Available water capacity is

moderate. Effective rooting depth is 20 to 40 inches. Runoff is

slow, and the hazard of water erosion is slight. A seasonal

perched water table is at a depth of 18 to 36 inches from

December to May. The effect of the layer of dense glacial

till on use and management is similar to that of a hardpan.

This unit is used as woodland, watershed, and wildlife

habitat.

Western hemlock is the main woodland species on this

unit. On the basis of a 100-year site curve, the mean site

index is 130. On the basis of a 50-year site curve, the mean site

index is 90. The mean annual increment at culmination (CMAI)

for western hemlock at age 50 is 200 cubic feet per acre.

Among the trees of limited extent are Pacific silver fir,

Douglas-fir, and western redcedar. The common forest

understory plants are red huckleberry, deer fern,

brackenfern, devilsclub, and ladyfern.

The main limitation for the harvesting of timber is seasonal

soil wetness. A seasonal perched water table limits the use of

equipment. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for yearround use. Rock

for road construction is not readily available on this unit.

Establishing plant cover on steep road cut and fill slopes reduces

erosion.

Seedling establishment and windthrow hazard are the

main concerns in the production of timber. If seed trees are

present, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically.

Reforestation can be accomplished by planting Douglas-fir

seedlings. When openings are made in the canopy, invading

brushy plants, if not controlled, can delay the establishment

of seedlings.

Because the rooting depth is restricted by the dense glacial

till, trees are occasionally subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly subject to

windthrow than are more deeply rooted trees.

The main limitations for homesites are the seasonal

perched water table and steepness of slope in areas where

slopes are more than 15 percent. Drainage is needed if buildings

with basements and crawl spaces are constructed. The dense

glacial till is rippable and therefore is not a serious limitation

for most engineering uses.

The main limitations for septic tank absorption fields are the

seasonal perched water table, depth to the dense glacial till,

and steepness of slope in areas where slopes are more

than 15 percent. Onsite sewage disposal systems often fail

or do not function properly during periods of high rainfall

because of the restrictive layer.

This map unit is in capability subclass VIe.

22-Getchell-Oso complex, 15 to 30 percent slopes. This

map unit is on mountainsides and ridgetops. Areas are irregular

in shape and are 10 to 120 acres in size. The native vegetation

is mainly conifers. Elevation is 1,800 to 2,600 feet. The average

annual precipitation is about 90 inches, the average annual

air temperature is about 43 degrees F, and the average

frost-free season is 90 to 125 days.

This unit is about 60 percent Getchell silt loam and about 25

percent Oso gravelly loam. The components of this unit are so

intricately intermingled that it was not practical to map them

separately at the scale used.

Included in this unit are small areas of Elwell, Hartnit,

Olomount, and Potchub soils. Also included are small areas of

Skykomish soils on terraces and outwash plains and areas

of Rock outcrop. Included areas make up about 15 percent

of the total acreage.

The Getchell soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically, the

surface is covered with a mat of needles, leaves, twigs, and

decomposed material about 2 inches thick. The surface layer is

black silt loam about 2 inches thick. The subsoil is yellowish

red, strong brown, light olive brown, and dark brown silt loam

about 34 inches thick. Olive, dense glacial till is at a depth of about

36 inches. Depth to glacial till ranges from 20 to 40 inches.
Permeability of the Getchell soil is moderate to the glacial

till and very slow through it. Available water capacity is

moderate. Effective rooting depth is 20 to 40 inches.

Runoff is medium, and the hazard of water erosion is

moderate. A seasonal perched water table is at a depth of 18

to 36 inches from December to May. The effect of the layer

of dense glacial till on use and management is similar to

that of a hardpan.

The Oso soil is moderately deep and moderately well drained.

It formed in glacial till, volcanic ash, and material derived

dominantly from andesite. Typically, the surface is covered with

a mat of leaves, needles, twigs, and mosses about 2

inches thick. The surface layer is black gravelly loam about 3

inches thick. The subsurface layer is light brownish gray

gravelly loam about 2 inches thick. The subsoil is dark

brown and yellowish brown gravelly loam about 24 inches

thick. Andesite is at a depth of about 29 inches. Depth to

andesite ranges from 20 to 40 inches.

Permeability of the Oso soil is moderate. Available water

capacity is moderate. Effective rooting depth is 20 to 40

inches. Runoff is medium, and the hazard of water

erosion is moderate. A seasonal perched water table is at

a depth of 18 to 36 inches from November to May.

This unit is used mainly as woodland, watershed, and

wildlife habitat.

Western hemlock is the main woodland species on the

Getchell soil. On the basis of a 100-year site curve, the

mean site index is 130. On the basis of a 50-year site

curve, the mean site index is 90. The mean annual increment at

culmination (CMAI) for western hemlock at age 50 is 200 cubic

feet per acre.

Western hemlock is also the main woodland species on

the Oso soil. On the basis of a 100-year site curve, the

mean site index is 129. On the basis of a 50-year site

curve, the mean site index is 93. The mean annual

increment at culmination (CMAI) for western hemlock

at age 50 is 198 cubic feet per acre.

Among the trees of limited extent on this unit are

Pacific silver fir, Douglas-fir, and western redcedar. Among

the common forest understory plants are red huckleberry,

deer fern, brackenfern, devilsclub, trailing blackberry,

blue-leaved huckleberry, and bunchberry dogwood.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment.

Snowpack also limits the use of equipment, and it restricts

access. Use of wheeled and tracked equipment when the

soils in this unit are wet produces ruts, compacts the soils,

and damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is readily

available on this unit. Establishing plant cover on steep road

cut and fill slopes reduces erosion.

Seedling establishment and windthrow hazard are the

main concerns for the production of timber. If seed trees

are present, natural reforestation of cutover areas by

western hemlock and Pacific silver fir occurs periodically.

Reforestation can be accomplished by planting Douglas-fir

seedlings. When openings are made in the canopy,

invading brushy plants, if not controlled, can delay the

establishment of seedlings.

Because the rooting depth is restricted by the depth to

bedrock and glacial till, trees are occasionally subject to

windthrow. Western hemlock, a shallow-rooted tree, is more

commonly subject to windthrow than are more deeply rooted

trees.

The main limitation for homesites on the Getchell soil is

the seasonal perched water table. Drainage is needed if

buildings with basements and crawl spaces are constructed

on it. The main limitation for septic tank absorption fields is

the glacial till and wetness.

Deep cuts in the Oso soil can expose bedrock.

Drainage is needed if buildings with basements and

crawl spaces are constructed. Depth to rock and

wetness limits the use of the soil for septic tank

absorption fields.

This map unit is in capability subclass VIe.

23-Getchell-Oso-Rock outcrop complex, 30 to 65

percent slopes. This map unit is on mountainsides. Areas

are irregular in shape and are 40 to 200 acres in size. The

native vegetation is mainly conifers. Elevation is 1,800 to

2,600 feet. The average annual precipitation is about 90

inches, the average annual air temperature is about 43

degrees F, and the average frost-free season is 90 to 125

days.

This unit is about 55 percent Getchell silt loam, about 30

percent Oso gravelly loam, and about 10 percent Rock

outcrop. The components of this unit are so intricately

intermingled that it was not practical to map them

separately at the scale used.

Included in this unit are small areas of Elwell, Hartnit,

Olomount, and Potchub soils on mountainsides and

ridgetops. Also included are Skykomish soils on terraces and

outwash plains. Included areas make up about 5 percent of

the total acreage.

The Getchell soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface is covered with a mat of needles, leaves, twigs,

and decomposed material about 2 inches thick. The surface

layer is black silt loam about 2 inches thick. The subsoil is

yellowish red, strong brown, light olive brown, and dark

brown silt loam about 34 inches thick. Olive, dense glacial

till is at a depth of about 36 inches. Depth to glacial till

ranges from 20 to 40 inches.

Permeability of the Getchell soil is moderate to the glacial

till and very slow through it. Available water capacity is

moderate. Effective rooting depth is 20 to 40 inches. Runoff

is medium, and the hazard of water erosion is moderate. A

seasonal perched water table is at a depth of 18 to 36

inches from December to May. The effect of the layer of

dense glacial till on use and management is similar to that

of a hardpan.
The Oso soil is moderately deep and moderately well

drained. It formed in glacial till, volcanic ash, and material

derived dominantly from andesite. Typically, the surface is

covered with a mat of leaves, needles, twigs, and mosses

about 2 inches thick. The surface layer is black gravelly loam

about 3 inches thick. The subsurface layer is light brownish gray

gravelly loam about 2 inches thick. The subsoil is dark brown

and yellowish brown gravelly loam about 24 inches thick.

Andesite is at a depth of about 29 inches. Depth to andesite

ranges from 20 to 40 inches.

Permeability of the Oso soil is moderate. Available

water capacity is moderate. Effective rooting depth is 20 to

40 inches. Runoff is medium, and the hazard of water

erosion is moderate. A seasonal perched water table is at a

depth of 18 to 36 inches from November to May.

Rock outcrop consists of areas where the surface is

exposed hard andesite or argillite.

This unit is used mainly as woodland, watershed, and wildlife

habitat.

Western hemlock is the main woodland species on the

Getchell soil. On the basis of a 100-year site curve, the

mean site index is 130. On the basis of a 50-year site curve,

the mean site index is 90. The mean annual increment at

culmination (CMAI) for western hemlock at age 50 is 200

cubic feet per acre.

Western hemlock is also the main woodland species on

the Oso soil. On the basis of a 100-year site curve, the

mean site index is 129. On the basis of a 50-year site

curve, the mean site index is 93. The mean annual increment

at culmination (CMAI) for western hemlock at age 50 is

198 cubic feet per acre.

Rock outcrop in this unit reduces yield by about 10

percent.

Among the trees of limited extent on this unit are Pacific

silver fir, Douglas-fir, and western redcedar. Among the

common forest understory plants are red huckleberry,

trailing blackberry, blue-leaved huckleberry, and bunchberry

dogwood.

The main limitations for the harvesting of timber are

steepness of slope, seasonal soil wetness, and areas of

Rock outcrop. Steepness of slope restricts the use of

wheeled and tracked equipment in skidding operations; cable

yarding systems generally are safer and disturb the soils less.

The seasonal perched water table limits the use of

equipment. Snowpack also limits the use of equipment,

and it restricts access. Unsurfaced roads and skid trails are

soft when wet, and they may be impassable during rainy

periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is readily available

on this unit. Rock outcrop hinders yarding operations.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or they are protected by plant cover. Establishing

plant cover on steep road cut and fill slopes reduces erosion.

Seedling establishment and windthrow hazard are the main

concerns for the production of timber. If seed trees are

present, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically.

Reforestation can be accomplished by planting Douglas-fir

seedlings. Rock outcrop limits the even distribution of

reforestation. When openings are made in the canopy,

invading brushy plants, if not controlled, can delay

establishment of seedlings.

Because the rooting depth is restricted by the glacial till

and underlying bedrock, trees are occasionally subject to

windthrow. Western hemlock, a shallow-rooted tree, is more

commonly subject to windthrow than are more deeply rooted

trees.

This map unit is in capability subclass Vlls.

24-Greenwater loamy sand. This very deep, somewhat

excessively drained soil is on terraces. It formed in alluvium

derived dominantly from andesite and pumice. Slope is 0 to

3 percent. Areas are 150 to 300 acres in size. The native

vegetation is mainly conifers. Elevation is 400 to 600 feet.

The average annual precipitation is about 60 inches, the

average annual air temperature is 49 degrees F, and the

average frost-free season is 140 to 160 days.

Typically, the surface is covered with a mat of needles,

leaves, twigs, and roots about 1 inch thick. The subsurface

layer is dark brown loamy sand about 2 inches thick. The

subsoil is dark brown loamy sand about 19 inches thick. The

substratum to a depth of 60 inches or more is dark gray

sand. In some areas the surface layer is sandy loam, the

soil does not contain volcanic ash, or slope is more than 3

percent.

Included in this unit are areas of Everett and Indianola

soils on terraces and outwash plains and Pilchuck soils on

flood plains. Included areas make up about 15 percent of

the total acreage.

Permeability of this Greenwater soil is rapid. Available

water capacity is low. Effective rooting depth is 60 inches or

more. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used mainly as woodland. It is also used for

urban development.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

151. On the basis of a 50-year site curve, the mean site

index is 116. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 60 is 159 cubic feet per acre.

Among the trees of limited extent are western hemlock and

red alder. The common forest understory plants are

oceanspray, western brackenfern, Oregon-grape, salal, and

western swordfern.

This unit is well suited to year-round logging. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

Brush competition is the main limitation for the

production of timber. When openings are made in the

canopy, invading brushy species, if not controlled, can
delay the establishment of seedlings. Reforestation can be

accomplished by planting Douglas-fir seedlings.

This unit is suited to urban development. The main

limitation for septic tank absorption fields is seepage. If

the density of housing is moderate to high, community

sewage systems may be needed to prevent contamination

of water supplies as a result of seepage from onsite

sewage disposal systems.

This map unit is in capability subclass IVs.

25-Hartnit-Potchub-Rock outcrop complex, 65 to 90

percent slopes. This map unit is on mountainsides. Areas are 25

to 160 acres in size. The native vegetation is mainly

conifers. Elevation is 2,600 to 3,600 feet. The average

annual precipitation is about 90 inches, the average annual

air temperature is about 41 degrees F, and the average frostfree season is 90 to 100 days.

This unit is about 50 percent Hartnit gravelly silt loam,

about 25 percent Potchub silt loam, and about 15 percent

Rock outcrop. The components of this unit are so intricately

intermingled that it was not practical to map them

separately at the scale used.

Included in this unit are small areas of Getchell, Oso,

and Verlot soils on mountainsides and ridgetops. Also included

are areas of talus below Rock outcrop. Included areas

make up about 10 percent of the total acreage.

The Hartnit soil is moderately deep and moderately well

drained. It formed in glacial till, volcanic ash, and material

derived dominantly from andesite, argillite, and basalt. Typically,

the surface is covered with a mat of leaves, needles, twigs,

and decomposed material about 7 inches thick. The

surface layer is black gravelly silt loam about 4 inches thick.

The subsurface layer is gray gravelly silt loam about 3 inches

thick. The subsoil is dark reddish brown, strong brown, and dark

brown gravelly silt loam about 20 inches thick. Andesite is at

a depth of about 27 inches. Depth to andesite ranges from

20 to 40 inches.

Permeability of the Hartnit soil is moderate. Available water

capacity is moderate. Effective rooting depth is 20 to 40

inches. Runoff is rapid, and the hazard of water erosion is

high.

The Potchub soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface is covered with a mat of leaves, needles, twigs,

and decomposed organic litter about 9 inches thick. The

surface layer is very dark brown silt loam about 7 inches

thick. The subsurface layer is pinkish gray silt loam about

3 inches thick. The subsoil is dark reddish brown, strong

brown, and dark brown silt loam about 24 inches thick.

Olive, dense glacial till is at a depth of about 34 inches.

Depth to glacial till ranges from 20 to 40 inches.

Permeability of the Potchub soil is moderate above the

glacial till and very slow through it. Available water capacity is

moderate. Effective rooting depth is 20 to 40 inches. Runoff

is rapid, and the hazard of water erosion is high. A

seasonal perched water table is at a depth of

18 to 36 inches from November to May. The effect of the

layer of dense glacial till on use and management is similar

to that of a hardpan.

Rock outcrop consists of areas of exposed andesite or

argillite. It occurs as steep cliffs.

This unit is used mainly as woodland and watershed.

Western hemlock is the main woodland species on the

Hartnit soil. On the basis of a 100-year site curve, the

estimated mean site index is 60. On the basis of a 50-year

site curve, the estimated mean site index is 45. The

estimated mean annual increment at culmination (CMAI)

for western hemlock at age 70 is 57 cubic feet per acre.

Western hemlock is also the main woodland species on

the Potchub soil. On the basis of a 100-year site curve, the

estimated mean site index is 68. On the basis of a 50-year

site curve, the estimated mean site index is 56. The

estimated mean annual increment at culmination (CMAI) for

western hemlock at age 60 is 70 cubic feet per acre.

Rock outcrop in this unit reduces yield by about 15

percent.

Among the trees of limited extent are Pacific silver fir

and Douglas-fir. The common forest understory plants are

red huckleberry, trailing blackberry, blue-leaved huckleberry,

bunchberry dogwood, and deer fern.

The main limitations for the harvesting of timber on this

unit are steepness of slope and Rock outcrop. The

seasonal perched water table in the Potchub soil limits the

use of equipment. Snowpack also limits the use of

equipment and restricts access. Cable yarding systems

generally are used on the unit. Harvesting systems that lift

logs entirely off the ground reduce the disturbance of the

protective layer of duff. Rock outcrop may hinder yarding

operations.

Unsurfaced roads and skid trails are soft when wet, and

they may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is readily available on this unit. Establishing

plant cover on steep cut and fill slopes reduces erosion.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or they are protected by plant cover. Following

road construction and clearcutting, road failures and

landslides are likely to occur.

Seedling establishment and windthrow hazard are the

main concerns in the production of timber. If seed trees are

present, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. Rock

outcrop limits the even distribution of reforestation. When

openings are made in the canopy, invading brushy plants,

if not controlled, can delay the establishment of seedlings.

Because the rooting depth is restricted by the underlying

bedrock in the Hartnit soil and the glacial till and seasonal

perched water table in the Potchub soil, trees are subject

to windthrow. Western hemlock, a shallow-rooted tree, is

more commonly subject to windthrow than are more

deeply rooted trees.
This map unit is in capability subclass VIIe.

26-Indianola loamy sand, 15 to 25 percent slopes.

This very deep, somewhat excessively drained soil is on terraces

and outwash plains. It formed in sandy glacial outwash.

Areas are 5 to 30 acres in size. The native vegetation is

mainly conifers. Elevation is 50 to 500 feet. The average

annual precipitation is about 40 inches, the average

annual air temperature is about 50 degrees F, and the

average frost-free season is 180 to 200 days.

Typically, the surface is covered with a mat of needles,

leaves, and twigs about 2 inches thick. The surface layer is

very dark grayish brown loamy sand about 4 inches

thick. The subsoil is dark yellowish brown loamy sand

about 20 inches thick. The substratum to a depth of 60

inches or more is light olive gray and grayish brown sand.

Included in this unit are small areas of soils that have

slopes of more than 25 percent. Also included are areas of

Everett, Indianola, Pastik, and Ragnar soils and Custer soils in

basins. Included areas make up about 15 percent of the total

acreage.

Permeability of this Indianola soil is rapid. Available water

capacity is low. Effective rooting depth is 60 inches or

more. Runoff is slow, and the hazard of water erosion is

slight.

This unit is used mainly as woodland and for urban

development.

Douglas-fir is the main woodland species on this unit

(fig. 2). On the basis of a 100-year site curve, the mean

site index is 156. On the basis of a 50-year site curve, the

mean site index is 112. The mean annual increment at

culmination (CMAI) for Douglas-fir at age 60 is 165 cubic

feet per acre. Among the trees of limited extent are western

redcedar, western hemlock, bigleaf maple, and red alder. The

common forest understory plants are brackenfern, salal,

western swordfern, trailing blackberry, and Oregon-grape.

This unit is well suited to year-round logging. Logging

roads require suitable surfacing for year-round use. Rock for

road construction is not readily available on this unit.

Establishing plant cover on steep road cut and fill slopes

reduces erosion.

Seedling mortality is the main limitation in the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. The droughtiness of the surface layer

increases seedling mortality, especially on the south- and

southwest-facing slopes. When openings are made in the

canopy, invading brushy plants, if not controlled, can delay

reforestation.

The main limitation for urban development is steepness

of slope. The main limitations for septic tank absorption

fields are steepness of slope and seepage. If the density

of housing is moderate to high, community sewage systems

may be needed to prevent contamination of water supplies

as a result of seepage from onsite sewage disposal

systems. Cutbanks on the soil in this unit are subject to

caving in.

This map unit is in capability subclass IVs.

Figure 2.- A young stand of Douglas-fir on Indianola

loamy sand, 15 to 25 percent slopes.

27-Kitsap silt loam, 0 to 8 percent slopes. This very

deep, moderately well drained soil is on terraces. It formed

in lacustrine sediment. Areas are 20 to 50 acres in size.

The native vegetation is mainly conifers and
hardwoods. Elevation is near sea level to 500 feet. The

average annual precipitation is about 40 inches, the

average annual air temperature is about 50 degrees F, and the

average frost-free season is 160 to 200 days.

Typically, the surface layer is dark grayish brown silt loam

about 6 inches thick. The upper part of the subsoil is dark

brown silt loam about 14 inches thick. The lower part is

olive brown silt loam about 13 inches thick. The substratum

to a depth of 60 inches or more is light olive brown silty clay

loam.

Included in this unit are small areas of soils that have a

surface layer and subsoil of fine sandy loam and loamy

sand. Also included are Alderwood soils on till plains,

Bellingham soils in depressional areas, and Ragnar soils on

outwash plains. Included areas make up about 15 percent

of the total acreage.

Permeability of this Kitsap soil is slow. Available water capacity

is high. Effective rooting depth is limited by a seasonal

perched water table that is at a depth of 18 to 30 inches

from December to May. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used as woodland and for hay and pasture,

cropland, and urban development.

Douglas-fir is the main woodland species on this unit.

On the basis of a 100-year site curve, the mean site index is

166. On the basis of a 50-year site curve, the main site

index is 123. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 60 is 177 cubic feet per acre.

Among the trees of limited extent are red alder, western

redcedar, and western hemlock. Among the common

forest understory plants are western swordfern, salal,

Oregon-grape, trailing blackberry, and evergreen huckleberry.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment

to dry periods. Use of wheeled and tracked equipment

when the soil in this unit is wet produces ruts, compacts the

soil, and damages the roots of trees. Unsurfaced roads and

skid trails are soft when wet and are impassable during rainy

periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is not readily

available on this unit.

Reforestation can be accomplished by planting Douglas-fir

seedlings. If seed trees are present, natural reforestation of

cutover areas by red alder occurs readily. When openings

are made in the canopy, invading brushy plants, if not

controlled, can prevent the establishment of seedlings.

Because the rooting depth is restricted by a seasonal

perched water table, trees are frequently subject to

windthrow. Wide spacing of trees in very young stands

reduces windthrow.

This unit is well suited to hay and pasture. Grazing

when the soil is wet results in compaction of the surface

layer, poor tilth, and excessive runoff. Use of proper

stocking rates, pasture rotation, and restricted grazing during

wet periods helps to keep the pasture in good condition and

to protect the soil from erosion. Periodic mowing and

spreading of droppings help to maintain

uniform growth, discourage selective grazing, and reduce clumpy

growth. Proper grazing practices, weed control, and

fertilizer are needed for maximum quality of forage.

Legumes benefit from applications of agricultural lime.

This unit is well suited to row crops. The perched water

table that develops during the rainy period in winter

generally limits the suitability of the unit for deep-rooted

crops. Tile drainage can be used to lower the water table if

a suitable outlet is available. Subsoiling increases ease

of root penetration.

A suitable cropping system is one that includes 1 or 2

years of oats, 3 or 4 years of strawberries, and 3 to 5

years of grasses and legumes. Annual cropping with

vegetables and growing a winter cover crop that is used as

green manure is also a suitable cropping system.

Returning all crop residue to the soil and using a cropping

system that includes grasses, legumes, or grass-legume

mixtures help to maintain fertility and tilth. Crusting of the

surface and compaction of the soil can be reduced by

returning crop residue to the soil and by using minimum

tillage. Grain and grasses respond to nitrogen; legumes

respond to phosphorus, boron, sulfur, and lime; and

vegetables and berries respond to nitrogen, phosphorus,

and potassium.

The main limitation for urban development is the

seasonal perched water table. Drainage is needed if

buildings with basements and crawl spaces are

constructed. The main limitations for septic tank

absorption fields are the seasonal perched water table

and slow permeability. Conventional septic tank absorption

fields often fail or do not function properly.

This map unit is in capability subclass lIe.

28-Kitsap silt loam, 8-to 25 percent slopes. This very

deep, moderately well drained soil is on terrace

escarpments. It formed in lacustrine sediment. Areas are 20

to 50 acres in size. The native vegetation is mainly conifers

and hardwoods. Elevation is near sea level to 500 feet. The

average annual precipitation is about 40 inches, the average

annual air temperature is about 50 degrees F, and the

average frost-free season is 160 to 200 days.

Typically, the surface layer is dark grayish brown silt

loam about 6 inches thick. The upper part of the subsoil is

dark brown silt loam about 14 inches thick. The lower part

is olive brown silty clay loam about 13 inches thick. The

substratum to a depth of 60 inches or more is light olive

brown silty clay loam. In some areas the surface layer and

subsoil are fine sandy loam and loamy sand.

Included in this unit are small areas of Alderwood soils on

till plains and Everett and Ragnar soils on terraces and

outwash plains. Included areas make up about 15 percent of

the total acreage.

Permeability of this Kitsap soil is slow. Available water

capacity is high. Effective rooting depth is limited by a

seasonal perched water table that is at a depth of 18 to 30

inches from December to May. Runoff is medium, and the

hazard of water erosion is moderate. The soil is subject to

hillside slippage.
This unit is used as woodland and for hay and pasture,

cropland, and urban development.

Douglas-fir is the main woodland species on this unit. On the

basis of a 100-year site curve, the mean site index is 166.

On the basis of a 50-year site curve, the mean site index is

123. The mean annual increment at culmination (CMAI) for

Douglas-fir at age 60 is 177 cubic feet per acre. Among the

trees of limited extent are red alder, western redcedar, and

western hemlock. Among the common forest understory

plants are western swordfern, salal, Oregon-grape, trailing

blackberry, and evergreen huckleberry.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment to dry

periods. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they are impassable during rainy

periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is not readily

available on this unit. Establishing plant cover on steep road

cut and fill slopes reduces erosion.

Reforestation can be accomplished by planting Douglas-fir

seedlings. If seed trees are present, natural reforestation of

cutover areas by red alder occurs readily. When openings

are made in the canopy, invading brushy plants, if not

controlled, can prevent the establishment of seedlings. Because

the rooting depth is restricted by a seasonal perched water

table, trees are frequently subject to windthrow. Wide

spacing of trees in very young stands will help reduce

windthrow.

This unit is suited to hay and pasture. Grazing when the soil is

wet results in compaction of the surface layer, poor tilth, and

excessive runoff. Use of proper stocking rates, pasture

rotation, and restricted grazing during wet periods helps to keep

the pasture in good condition and to protect the soil from

erosion. Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing. Proper

grazing practices, weed control, and fertilizer are needed for

maximum quality of forage. Legumes benefit from applications of

agricultural lime.

This unit is suited to use as cropland. Steepness of slope

is the main limitation. The seasonal perched water table that

develops during the rainy period in winter generally limits

the suitability of the unit for deep-rooted plants. Tile

drainage can be used to lower the water table if a suitable

outlet is available.

A suitable cropping system is one that includes 1 or 2

years of oats and 3 to 5 years of grasses and legumes.

Returning all crop residue to the soil and using a cropping

system that includes grasses, legumes, or grass-legume

mixtures help to maintain fertility and tilth. Crusting of the

surface and compaction of the soil can be reduced by

returning crop residue to the soil and by using minimum

tillage. Tillage should be on the contour or across the slope.

Grain and grasses respond to

nitrogen; legumes respond to phosphorus, boron, sulfur, and

lime; and vegetables and berries respond to nitrogen,

phosphorus, and potassium.

The main limitations for building sites are the hazard of

hillside slippage and seasonal soil wetness. Steepness of

slope is a limitation in areas where slopes are more than 15

percent. Drainage is needed if buildings with basements and

crawl spaces are constructed. The soil in this unit may

slump readily in excavated areas.

The main limitations for septic tank absorption fields are

the seasonal perched water table, slow permeability, and

steepness of slope in areas where slopes are more than 15

percent. Conventional septic tank absorption fields often fail

or do not function properly.

This map unit is in capability subclass Ille.

29-Kitsap silt loam, 25 to 50 percent slopes. This very

deep, moderately well drained soil is on terrace escarpments.

It formed in lacustrine sediment. Areas are 10 to 50 acres in

size. The native vegetation is mainly conifers and

hardwoods. Elevation is near sea level to 500 feet. The

average annual precipitation is about 40 inches, the average

annual air temperature is about 50 degrees F, and the

average frost-free season is 160 to 200 days.

Typically, the surface layer is dark grayish brown silt loam

about 6 inches thick. The upper part of the subsoil is dark

brown silt loam about 14 inches thick. The lower part is

olive brown silty clay loam about 13 inches thick. The

substratum to a depth of 60 inches or more is light olive

brown silty clay loam. In some areas the surface layer and

subsoil are fine sand and loamy sand.

Included in this unit are small areas of Alderwood soils on

till plains and Everett and Ragnar soils on terraces and

outwash plains. Included areas make up about 15 percent of

the total acreage.

Permeability of this Kitsap soil is slow. Available

water capacity is high. Effective rooting depth is limited by a

seasonal perched water table that is at a depth of 18 to 30

inches from December to May. Runoff is rapid, and the

hazard of water erosion is high. The soil is subject to hillside

slippage. Seep areas or springs are common.

This unit is used as woodland and open space in

urban areas.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

166. On the basis of a 50-year site curve, the mean site

index is 123. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 60 is 177 cubic feet per

acre. Among the trees of limited extent are red alder,

western redcedar, and western hemlock. Among the

common forest understory plants are western swordfern,

salal, Oregon-grape, trailing blackberry, and evergreen

huckleberry.

The main limitation for the harvesting of timber is seasonal

soil wetness, which limits the use of equipment to dry

periods. The steep slopes restrict the use of wheeled and

tracked equipment in skidding operations.
Unsurfaced roads and skid trails are soft when wet, and they

are impassable during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

Establishing plant cover on steep road cut and fill slopes

reduces erosion. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or they are protected

by plant cover. Following road construction and harvesting,

road failure and landslides are likely. Because the rooting

depth is restricted by a seasonal perched water table, trees

are frequently subject to windthrow.

Reforestation can be accomplished by planting Douglas-fir

seedlings. If seed trees are present, natural reforestation of

cutover areas by red alder occurs readily. When openings are

made in the canopy, invading brushy plants, if not controlled,

can prevent the establishment of seedlings.

The main limitations for building sites are steepness of

slope, the hazard of hillside slippage, and soil wetness. Drainage

is needed if buildings with basements and crawl spaces

are constructed. Access roads must be designed to control

surface runoff and help stabilize cut slopes. The soil in this

unit may slump readily in excavated areas.

The main limitations for septic tank absorption fields are

the seasonal perched water table, slow permeability, and

steepness of slope. Conventional septic tank absorption

fields often fail or do not function properly.

This map unit is in capability subclass VIe.

30-Lynnwood loamy sand, 0 to 3 percent slopes. This

very deep, somewhat excessively drained soil is on terraces and

outwash plains. It formed in glacial outwash. Areas

generally are 10 to 30 acres in size, but a few areas are as

much as 600 acres. The native vegetation is mainly conifers.

Elevation is 50 to 500 feet. The average annual precipitation

is about 40 inches, the average annual air temperature is

about 49 degrees F, and the average frost-free season is

180 to 200 days.

Typically, the surface is covered with a mat of leaves,

needles, and twigs about 3 inches thick. The surface layer is

grayish brown loamy sand about 1 inch thick. The upper part

of the subsoil is dark brown loamy sand about 14 inches

thick. The lower part is dark yellowish brown loamy sand

about 14 inches thick. The substratum to a depth of 60

inches or more is grayish brown sand. In some areas the

surface layer and subsoil are sandy loam.

Included in this unit are small areas of Everett, Indianola,

Pastik, and Ragnar soils. Also included are Custer soils in basins

and soils that have slopes of more than 3 percent. Included

areas make up about 15 percent of the total acreage.

Permeability of this Lynnwood soil is rapid. Available water

capacity is low. Effective rooting depth is 60 inches or more.

Runoff is slow, and the hazard of water erosion is slight.

This unit is used mainly as woodland and for urban

development. It is also used for hay and pasture.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

158. On the basis of a 50-year site curve, the mean site

index is 121. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 65 is 168 cubic feet per

acre. Among the trees of limited extent are western hemlock

and western redcedar. Among the common forest understory

plants are western swordfern, brackenfern, deer fern, and

red huckleberry.

This unit is well suited to year-round logging. Logging

roads require suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

Reforestation can be accomplished by planting Douglasfir seedlings. The droughtiness of the surface layer reduces

the survival of seedlings. When openings are made in

the canopy, invading brushy plants, if not controlled, can

delay the establishment of seedlings.

The main limitation for hay and pasture is low available

water capacity. Use of proper stocking rates, pasture

rotation, and restricted grazing during wet periods helps to

keep the pasture in good condition. Proper grazing practices,

weed control, and fertilizer are needed for maximum quality

of forage. In most years supplemental irrigation is needed.

Fertilizer is needed for optimum growth of grasses and

legumes.

This unit is suited to use as homesites. The main limitation

for septic tank absorption fields is seepage. If the density of

housing is moderate to high, community sewage systems

are needed to prevent contamination of water supplies as a

result of seepage from onsite sewage disposal systems.

Cutbanks are not stable and are subject to caving in.

This map unit is in capability subclass IVs.

31-Lynnwood-Nargar complex, 65 to 90 percent

slopes. This map unit is on terrace escarpments. Areas are

irregular in shape and are 20 to 200 acres in size. The

native vegetation is mainly conifers. Elevation is 400 to

1,200 feet. The average annual precipitation is about 55

inches, the average annual air temperature is about 48

degrees F, and the average frost-free season is 140 to 190

days.

This unit is about 60 percent Lynnwood loamy sand and

about 25 percent Nargar fine sandy loam. The

components of this unit are so intricately intermingled that

it was not practical to map them separately at the scale

used.

Included in this unit are small areas of Pastik, Everett,

Skykomish, and Winston soils on terraces and outwash

plains and soils that have a gravelly sandy loam surface

layer. Included areas make up about 15 percent of the total

acreage.

The Lynnwood soil is very deep and somewhat

excessively drained. It formed in glacial outwash.

Typically, the surface is covered with a mat of leaves,

needles, and twigs about 3 inches thick. The surface
layer is grayish brown loamy sand about 1 inch thick. The upper

part of the subsoil is dark brown loamy sand about 14

inches thick. The lower part is dark yellowish brown

loamy sand about 14 inches thick. The substratum to a depth

of 60 inches or more is grayish brown sand.

Permeability of the Lynnwood soil is rapid. Available

water capacity is low. Effective rooting depth is 60 inches

or more. Runoff is medium, and the hazard of water erosion is

moderate.

The Nargar soil is very deep and well drained. It formed

in sandy alluvium and volcanic ash. Typically, the surface is

covered with a mat of needles, leaves, twigs, and partially

decomposed litter about 1 inch thick. The surface layer,

where mixed to a depth of about 6 inches, is yellowish red

fine sandy loam. The subsoil is yellowish red, brown, and

dark yellowish brown fine sandy loam about 20 inches

thick. The upper part of the substratum is olive gray, stratified

fine sand to coarse sand about 15 inches thick. The lower

part to a depth of 60 inches or more is light olive brown and

olive gray very gravelly loamy sand.

Permeability of the Nargar soil is moderate. Available water

capacity is moderate. Effective rooting depth is 60 inches or

more. Runoff is rapid, and the hazard of water erosion is

high.

This unit is used mainly as woodland and for wildlife

habitat.

Douglas-fir is the main woodland species on the

Lynnwood soil. On the basis of a 100-year site curve, the

mean site index is 158. On the basis of a 50-year site

curve, the mean site index is 121. The mean annual

increment at culmination (CMAI) for Douglas-fir at age 65 is

168 cubic feet per acre.

Douglas-fir is also the main woodland species on the

Nargar soil. On the basis of a 100-year site curve, the

mean site index is 185. On the basis of a 50-year site curve,

the mean site index is 138. The mean annual increment at

culmination (CMAI) for Douglas-fir at age 60 is 195 cubic

feet per acre.

Among the trees of limited extent on this unit are western

hemlock and western redcedar. Red alder is of limited

extent on the Nargar soil. Among the common forest

understory plants are western swordfern, brackenfern,

ladyfern, deer fern, red huckleberry, vine maple, and salal.

The main limitation for the harvesting of timber is steepness of

slope. Cable yarding systems generally are used on this unit.

Harvesting systems that lift logs entirely off the ground

reduce the disturbance of the protective layer of duff.

Logging roads require suitable surfacing for year-round

use. Rock for road construction is not readily available on

this unit.

Establishing plant cover on steep road cut and fill slopes

reduces erosion. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless adequate

water bars are provided or they are protected by plant

cover. Following road construction and clearcutting, road

failures and landslides are likely to occur.

Brush competition is the main limitation in the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of red alder occurs readily and natural

reforestation of western hemlock occurs periodically on the

Nargar soil. The droughtiness of the surface layer of the

Lynnwood soil reduces the survival of seedlings,

especially on south- and southwest-facing slopes.

When openings are made in the canopy, invading brushy

plants, if not controlled, can prevent the establishment of

seedlings on the Nargar soil and delay establishment on the

Lynnwood soil.

This map unit is in capability subclass VIIe.

32-McKenna gravelly silt loam, 0 to 8 percent

slopes. This moderately deep, poorly drained soil is in

depressional areas and drainageways on till plains. It

formed in glacial till. The native vegetation is mainly

conifers. Elevation is 100 to 800 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 150 to 180 days.

Typically, the surface layer is very dark grayish brown

gravelly silt loam about 8 inches thick. The subsoil is brown

and light olive brown gravelly silt loam about 25 inches thick.

Olive, compact glacial till is at a depth of 33 inches. Depth to

glacial till ranges from 20 to 40 inches.

Included in this unit are small areas of soils that have

slopes of more than 8 percent. Also included are Alderwood

and Tokul soils on till plains, Everett soils on terraces and

outwash plains, and Norma soils and Terric Medisaprists in

depressional areas and on outwash plains and till plains.

Included areas make up about 15 percent of the total

acreage.

Permeability of this McKenna soil is slow. Available water

capacity is moderate. Effective rooting depth is 20 to 40

inches. Runoff is slow, and the hazard of erosion is slight. A

seasonal perched water table is at a depth of 0 to about 6

inches. Ponding occurs from November to April. The effect

of the layer of dense glacial till on use and management is

similar to that of a hardpan.

This unit is used mainly as woodland and for hay and

pasture.

Red alder and western redcedar are the main woodland

species on this unit. On the basis of a 50-year site curve, the

mean site index is 90 for red alder. The mean annual

increment at culmination (CMAI) for red alder at age 40 is

101 cubic feet per acre. Estimates of the site index or yield

for western redcedar have not been made. Among the trees

of limited extent is western hemlock. Among the common

forest understory plants are Oregon-grape, red huckleberry,

trailing blackberry, western swordfern, and Oregon oxalis.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment to

dry periods. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced
roads and skid trails are soft when wet, and they are

impassable during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

Seedling mortality, brush competition, and windthrow hazard

are the main limitations in the production of timber. If

seed trees are present, natural reforestation of cutover

areas by red alder occurs periodically. Western

redcedar may be suitable for reforestation. Seasonal

wetness and ponding reduce root respiration, which

results in high seedling mortality. When openings are made in the

canopy, invading brushy plants, if not controlled, can delay the

establishment of seedlings. Because the rooting depth is

restricted by the layer of glacial till, trees are commonly

subject to windthrow.

This unit is used for hay and pasture. The main limitation

is a seasonal perched water table. Grazing when the soil is wet

results in compaction of the surface layer, poor tilth, and

excessive runoff. Excessive water on the surface can be

removed by tile drainage systems if suitable outlets are

available. Use of proper stocking rates, pasture rotation,

and restricted grazing during wet periods helps to keep the

pasture in good condition.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. Fertilizer is needed for

optimum growth of grasses and legumes. Legumes

benefit from applications of agricultural lime.

The main limitation for building sites is ponding. Drainage

is needed if buildings with basements and crawl spaces are

constructed.

The main limitations for septic tank absorption fields

are depth to the dense glacial till, the seasonal perched

water table, ponding, and moderately slow permeability.

Conventional septic tank absorption fields often fail or do

not function properly. The use of long absorption lines helps

to compensate for the moderately slow permeability. Drainage

is needed if septic tank absorption fields are installed.

This map unit is in capability subclass IVw.

33-Menzel silt loam, 0 to 3 percent slopes. This

very deep, well drained soil is on terraces. It formed in

alluvium and volcanic ash. Areas are 20 to 80 acres in

size. The native vegetation is mainly conifers. Elevation is 200

to 500 feet. The average annual precipitation is about 55

inches, the average annual air temperature is about 49

degrees F, and the average frost-free season is 140 to

200 days.

Typically, the surface is covered with matted roots about

1 inch thick. The surface layer is very dark brown silt loam

about 4 inches thick. The subsoil is strong brown and dark

yellowish brown silt loam and very fine sandy loam about

12 inches thick. The substratum to a depth of 60 inches or

more is light olive brown fine sandy loam. In some areas

the substratum is sand and gravelly sand.

Included in this unit are small areas of Puyallup

soils on stream terraces, Sultan soils on flood plains, and

Nargar soils on high terraces, terrace escarpments, and

outwash plains. Included areas make up about 15 percent

of the total acreage.

Permeability of this Menzel soil is moderate.

Available water capacity is high. Effective rooting depth is

60 inches or more. Runoff is slow, and the hazard of water

erosion is slight. Flooding is rare.

This unit is used mainly for hay and pasture. It is also

used as woodland and for homesite development.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

179. On the basis of a 50-year site curve, the mean site

index is 180. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 60 is about 190 cubic feet

per acre. Among the trees of limited extent are western

hemlock, western redcedar, and red alder. Among the

common forest understory plants are western swordfern, red

huckleberry, vine maple, ladyfern, and deer fern.

The main limitation for the harvesting of timber is seasonal

soil wetness. Use of wheeled and tracked equipment when

the soil in this unit is wet produces ruts, compacts the soil,

and damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is not readily

available on this unit.

Brush competition is the main concern in the production of

timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. When openings are made in the

canopy, invading brushy plants, if not controlled, can prevent

reforestation.

This unit is well suited to hay and pasture. Use of proper

stocking rates, pasture rotation, and restricted grazing during

wet periods helps to maintain uniform growth, discourage

selective grazing, and reduce clumpy growth. Proper grazing

practices, weed control, and fertilizer are needed for

maximum quality of forage. In some years supplemental

irrigation is also needed.

The main limitation for homesites and septic tank

absorption fields is the hazard of flooding. Flooding can be

controlled only by use of major flood control structures.

This map unit is in capability subclass llc.

34-Mukilteo muck. This very deep, very poorly drained

soil is in depressional areas. It formed in organic material

derived dominantly from sedges. Areas are irregular in

shape and are 20 to 80 acres in size. The native vegetation

is mainly sedges and rushes. Elevation is 20 to 1,000 feet.

Slope is 0 to 1 percent. The average annual precipitation is

about 55 inches, the average annual air temperature is about

50 degrees F, and the

average frost-free season is 150 to 200 days.

Typically, the upper layer is dark reddish brown muck

about 4 inches thick. The next layer is dark reddish brown

and black organic material about 31 inches thick. The next

layer is black organic material about 19 inches
thick. Below this to a depth of 60 inches or more is olive

gray fine sandy loam. In some areas a large amount of

woody material is in the profile.

Included in this unit are areas of Terric Medisaprists, Orcas

peat, and Mukilteo soils that have not been artificially

drained. Included areas make up about 10 percent of the

total acreage.

Permeability of this Mukilteo soil is moderate. Available water

capacity is high. Effective rooting depth is limited by a high

water table that is at or near the surface from October to

May. Runoff is ponded. In most areas of this unit, the water

table is artificially drained to a depth of about 3 or 4 feet

during the growing season. Some areas are ponded during

the rainy season.

This unit is used as cropland and for pasture and

wildlife habitat.

This unit, when drained, is well suited to row crops. Tile

drainage can be used to lower the water table if a suitable

outlet is available. Subsidence is minimized if the water table

is maintained immediately below the root zone and is

allowed to return to the surface when crops are not being

grown.

A suitable cropping system includes 1 or 2 years of oats, 3 or 4

years of blueberries, and 3 to 5 years of grasses and legumes.

Continuous cropping with vegetables is suitable if an annual

winter cover crop is grown. Returning all crop residue to

the soil and using a cropping system that includes grasses,

legumes, or grass-legume mixtures help to maintain fertility and

tilth. Grain and grasses respond to nitrogen; legumes respond to

phosphorus, boron, sulfur, and lime; and vegetables and

berries respond to nitrogen, phosphorus, and potassium.

This unit, when drained, is suited to hay and pasture. Grazing

when the soil in this unit is wet results in compaction of the

surface layer. Excessive water on the surface can be

removed by a tile system if a suitable outlet is available.

Use of proper stocking rates, pasture rotation, and

restricted grazing during wet periods helps to keep the

pasture in good condition.

Periodic mowing and spreading of droppings help to maintain

uniform growth and discourage selective grazing. Proper

grazing practices, weed control, and fertilizer are needed for

maximum quality of forage. Fertilizer is needed for

optimum growth of grasses and legumes. Legumes

also benefit from applications of agricultural lime.

The soil in this unit is not suited to urban development.

The main limitations for homesites are ponding and low soil

strength. The main limitation for septic tank absorption

fields is ponding. Conventional septic tank absorption systems

fail or do not function properly on this unit.

This map unit is in capability subclass Ilw.

35-Nargar fine sandy loam, 0 to 15 percent slopes.

This very deep, well drained soil is on high terraces. It

formed in sandy alluvium and volcanic ash.

Areas are 20 to 80 acres in size. The native vegetation is

mainly conifers. Elevation is 400 to 1,200 feet. The

average annual precipitation is about 65 inches, the

average annual air temperature is about 46 degrees F,

and the average frost-free season is 120 to 180 days.

Typically, the surface is covered with a mat of needles,

leaves, twigs, and partially decomposed litter about 1 inch

thick. The surface layer, where mixed to a depth of about 6

inches, is yellowish red fine sandy loam. The subsoil is

yellowish red, brown, and dark yellowish brown fine sandy

loam about 20 inches thick. The upper part of the

substratum is olive gray, stratified fine sand to coarse sand

about 15 inches thick. The lower part of the substratum to

a depth of 60 inches or more is light olive brown and

olive gray very gravelly loamy coarse sand. In some

areas the surface layer is loam or gravelly loam.

Included in this unit are areas of Indianola, Pastik, and

Winston soils on terraces and outwash plains. Included

areas make up about 15 percent of the total acreage.

Permeability of this Nargar soil is moderate. Available

water capacity is moderate. Effective rooting depth is 60

inches or more. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

185. On the basis of a 50-year site curve, the mean site

index is 138. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 60 is 195 cubic feet per

acre. Among the trees of limited extent are western

hemlock, western redcedar, and red alder. Among the

common forest understory plants are western swordfern,

brackenfern, red huckleberry, ladyfern, vine maple, and

salal.

The main limitation for the harvesting of timber is seasonal

soil wetness. Use of wheeled and tracked equipment when

the soil in this unit is wet produces ruts, compacts the soil,

and damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable surfacing

for year-round use. Rock for road construction is not readily

available on this unit.

Reforestation can be accomplished by planting Douglasfir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily

and natural regeneration of western hemlock occurs

periodically. When openings are made in the canopy,

invading brushy plants, if not controlled, can prevent

reforestation.

This unit is suited to use as homesites. The main limitation

for septic tank absorption fields is the hazard of seepage. If

the density of housing is moderate to high, community

sewage systems may be needed to prevent contamination of

water supplies as a result of seepage from onsite sewage

disposal systems. Cutbanks are not stable and are

subject to caving in.

This map unit is in capability subclass Ille.
36-Nargar fine sandy loam, 15 to 30 percent slopes.

This very deep, well drained soil is on high terraces and

terrace escarpments. It formed in sandy alluvium and

volcanic ash. Areas are 15 to 40 acres in size. The

native vegetation is mainly conifers. Elevation is 400 to 1,200

feet. The average annual precipitation is about 65

inches, the average annual air temperature is about 46

degrees F, and the average frost-free season is 120 to

180 days.

Typically, the surface is covered with a mat of needles,

leaves, twigs, and partially decomposed litter about 1 inch

thick. The surface layer, where mixed to a depth of

about 6 inches, is yellowish red fine sandy loam. The

subsoil is yellowish red, brown, and dark yellowish brown

fine sandy loam about 20 inches thick. The upper part of

the substratum is olive gray, stratified fine sand to

coarse sand about 15 inches thick. The lower part to a

depth of 60 inches or more is light olive brown and olive gray

very gravelly loamy sand. In some areas the surface layer is

loam or is gravelly fine sandy loam.

Included in this unit are areas of Indianola, Pastik, and Winston

soils on terraces and outwash plains. Included areas make up

about 15 percent of the total acreage.

Permeability of this Nargar soil is moderate. Available water

capacity is moderate. Effective rooting depth is 60 inches

or more. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland.

Douglas-fir is the main woodland spec .as on this unit. On

the basis of a 100-year site curve, the mean site index is

185. On the basis of a 50-year site curve, the mean site

index is 138. The mean annual increment at culmination (CMAI) for

Douglas-fir at age 60 is 195 cubic feet per acre. Among the

trees of limited extent are western hemlock, western redcedar,

and red alder. Among the common forest understory plants

are western swordfern, red huckleberry, brackenfern,

ladyfern, vine maple, and salal.

The main limitation for the harvesting of timber is seasonal

soil wetness. Use of wheeled and tracked equipment

when the soil in this unit is wet produces ruts, compacts the

soil, and damages the roots of trees. Unsurfaced roads and

skid trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable

surfacing for year-round use. Rock for road construction is

not readily available on this unit. Establishing plant cover on

steep road cut and fill slopes reduces erosion.

Brush competition is the main limitation in the production of

timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs

readily and natural regeneration of western hemlock

occurs periodically. When openings are made in the canopy,

invading brushy plants, if not controlled, can prevent

reforestation.

The main limitation for homesites is steepness of slope.

The main limitations for septic tank absorption

fields are steepness of slope and seepage. If the density of

housing is moderate to high, community sewage systems

may be needed to prevent contamination of water supplies

as a result of seepage from onsite sewage disposal

systems. Cutbanks are not stable and are subject to

caving in.

This map unit is in capability subclass IVe.

37-Nargar-Lynnwood complex, 30 to 65 percent

slopes. This map unit is on terrace escarpments. Areas are

irregular in shape and are 10 to 40 acres in size. The native

vegetation is mainly conifers. Elevation is 400 to 1,200 feet.

The average. annual precipitation is about 55 inches, the

average annual air temperature is about 48 degrees F, and

the average frost-free season is 140 to 190 days.

This unit is about 60 percent Nargar fine sandy loam

and about 25 percent Lynnwood loamy sand. The

components of this unit are so intricately intermingled that

it was not practical to map them separately at the scale

used.

Included in this unit are small areas of Pastik,

Skykomish, and Winston soils on terraces and outwash

plains. Included areas make up about 15 percent of the

total acreage.

The Nargar soil is very deep and well drained. It formed in

sandy alluvium and volcanic ash. Typically, the surface is

covered with a mat of needles, leaves, and partially

decomposed litter about 1 inch thick. The surface layer,

where mixed to a depth of about 6 inches, is yellowish red

fine sandy loam. The subsoil is yellowish red, brown, and

dark yellowish brown fine sandy loam about 20 inches thick.

The upper part of the substratum is olive gray, stratified fine

sand and coarse sand about 15 inches thick. The lower part

to a depth of 60 inches or more is light olive brown and olive

gray very gravelly loamy sand.

Permeability of the Nargar soil is moderate. Available

water capacity is moderate. Effective rooting depth is 60

inches or more. Runoff is rapid, and the hazard of water

erosion is high.

The Lynnwood soil is very deep and somewhat excessively

drained. It formed in glacial outwash. Typically, the surface is

covered with a mat of leaves, needles, and twigs about 3

inches thick. The surface layer is grayish brown loamy sand

about 1 inch thick. The upper part of the subsoil is dark

brown loamy sand about 14 inches thick. The lower part is

dark yellowish brown loamy sand about 14 inches thick. The

substratum to a depth of 60 inches or more is grayish brown

sand.

Permeability of the Lynnwood soil is rapid.

Available water capacity is low. Effective rooting depth is

60 inches or more. Runoff is medium, and the hazard of

water erosion is moderate.

This unit is used mainly as woodland.

Douglas-fir is the main woodland species on the

Nargar soil. On the basis of a 100-year site curve, the

mean site index is 185. On the basis of a 50-year site
curve, the mean site index is 138. The mean annual

increment at culmination (CMAI) for Douglas-fir at age 60 is 195

cubic feet per acre.

Douglas-fir is also the main woodland species on the

Lynnwood soil. On the basis of a 100-year site curve, the

mean site index is 158. On the basis of a 50-year site curve,

the mean site index is 121. The mean annual increment at

culmination (CMAI) for Douglas-fir at age 65 is 168 cubic feet

per acre.

Among the trees of limited extent on this unit are western

hemlock and western redcedar. Red alder is also of limited

extent on the Nargar soil. Among the common forest

understory plants are western swordfern, brackenfern,

ladyfern, deer fern, red huckleberry, vine maple, and salal.

The main limitation for the harvesting of timber is

steepness of slope, which restricts the use of wheeled and

tracked equipment in skidding operations. Cable yarding

systems generally are safer and disturb the soil less. Use of

wheeled and tracked equipment when the soils in this

unit are wet produces ruts, compacts the soils, and

damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is not readily

available on this unit. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless adequate

water bars are provided or they are protected by plant

cover.

Seedling establishment and brush competition are the

main limitations for the production of timber.

Reforestation can be accomplished by planting Douglas-fir

seedlings. If seed trees are present, natural reforestation

of cutover areas by red alder occurs readily and natural

regeneration of western hemlock occurs periodically on

the Nargar soil. The droughtiness of the surface layer of

the Lynnwood soil increases seedling mortality,

especially on south- and southwest-facing slopes. When

openings are made in the canopy, invading brushy plants, if

not controlled, can delay the establishment of seedlings

on the Lynnwood soil and prevent establishment on the

Nargar soil.

This map unit is in capability subclass VIle.

38-Nargar Variant sandy loam, 3 to 30 percent

slopes. This very deep, well drained soil is on terrace

escarpments and mountainsides. It formed in sandy alluvium

and volcanic ash. Areas are 10 to 80 acres in size. The native

vegetation is mainly conifers. Elevation is 800 to 1,800 feet. The

average annual precipitation is

about 70 inches, the average annual air temperature is

about 45 degrees F, and the average frost-free season

is 110 to 140 days.

Typically, the surface is covered with a mat of leaves,

twigs, and needles about 2 inches thick. The surface layer

is very dark grayish brown sandy loam about 4 inches

thick. The subsoil is reddish brown, dark brown, and dark

yellowish brown sandy loam about 27 inches

thick. The substratum to a depth of 60 inches or more is

yellowish brown and light olive brown loamy coarse sand and

very gravelly coarse sandy loam. In some areas the

surface layer and subsoil are sandy loam.

Included in this unit are areas of Skykomish soils on

terraces and outwash plains and Elwell soils on

mountainsides and ridgetops. Included areas make up about

15 percent of the total acreage.

Permeability of this Nargar Variant soil is moderate to

the substratum and rapid through it. Available water capacity

is low. Effective rooting depth is 60 inches or more. Runoff is

medium, and the hazard of water erosion is moderate.

This unit is used as woodland.

Western hemlock is the main woodland species on this

unit. On the basis of a 100-year site curve, the mean site

index is 133. On the basis of a 50-year site curve, the mean

site index is 92. The mean annual increment at culmination

(CMAI) for western hemlock at age 50 is 205 cubic feet per

acre. Among the trees of limited extent are Douglas-fir and

western redcedar. Among the common forest understory

plants are vine maple, swordfern, red huckleberry, trillium,

and brackenfern.

The main limitation for the harvesting of timber is seasonal

soil wetness. Use of wheeled and tracked equipment when

the soil in this unit is wet produces ruts, compacts the soil,

and damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Establishing plant cover on steep road cut and

fill slopes reduces erosion.

Seedling mortality and brush competition are the main

limitations in the production of timber. Reforestation can be

accomplished by planting Douglas-fir seedlings. If seed

trees are present, natural reforestation of cutover areas by

western hemlock occurs periodically. High soil temperature

and low soil moisture content during the growing season

cause a high mortality of seedlings, especially on southand southwest-facing slopes. When openings are made in

the canopy, invading brushy

plants, if not controlled, can delay reforestation.

The main limitation for homesites is steepness of slope in

areas where slopes are more than 15 percent. The main

limitations for septic tank absorption fields are steepness of

slope and seepage. If the density of housing is moderate to

high, community sewage systems may be needed to prevent

contamination of water supplies as a result of seepage from

onsite sewage disposal systems. Cutbanks are not stable

and are subject to caving in.

This map unit is in capability subclass IVe.

39-Norma loam. This very deep, poorly drained soil is in

depressional areas on outwash plains and till plains. It

formed in alluvium. Areas are 10 to 40 acres in size. The

native vegetation is mainly hardwood trees. Elevation is 20

to 600 feet. Slope is 0 to 3 percent. The average annual

precipitation is about 45 inches, the
average annual air temperature is about 50 degrees F, and

the average frost-free season is 150 to 200 days.

Typically, the surface layer is very dark gray loam about 10

inches thick. The subsoil is dark grayish brown sandy loam

about 18 inches thick. The substratum to a depth of 60

inches or more is dark gray sandy loam.

Included in this unit are small areas of soils that have a

surface layer and subsoil of silt loam and soils that have a

gravelly and sandy subsoil. Also included are areas of

Bellingham and Custer soils and Terric Medisaprists in

depressional areas. Included areas make up about 15 percent

of the total acreage.

Permeability of this Norma soil is moderately rapid. Available

water capacity is moderate. Effective rooting depth is limited by

a seasonal high water table that is at a depth of 0 to about

12 inches. Runoff is very slow, and the hazard of water

erosion is slight. Ponding occurs from November to April.

In most areas the water table is artificially drained to a depth

of about 3 or 4 feet during the growing season, but the soil

may be ponded during the rainy season.

This unit is used mainly for hay and pasture and for wildlife

habitat. It is also used as woodland and cropland.

This unit, when drained, is well suited to use as cropland.

Proper row arrangement, field ditches, and vegetated outlets

are needed to remove excess surface water. Tile drainage

can be used to lower the water table if a suitable outlet is

available.

A suitable cropping system includes 1 or 2 years of

sweet corn, 1 to 5 years of raspberries or strawberries,

and 3 to 5 years of grasses and legumes. Annual

cropping with vegetables and growing a winter cover crop is also

suitable. Returning all crop residue to the soil and using a

cropping system that includes grasses, legumes, or grasslegume mixtures help to maintain fertility and tilth. Returning

crop residue to the soil also reduces compaction. Grain and

grasses respond to nitrogen; legumes respond to phosphorus,

boron, sulfur, and lime; and vegetables and berries respond to

nitrogen, phosphorus, and potassium.

This unit, when drained, is well suited to hay and

pasture. Wetness and submergence limit the choice of plants

and the period of cutting or grazing, and they increase

the risk of damaging crops. Grazing when the soil in this unit

is wet results in compaction of the surface layer.

Excessive water on the surface can be removed by tile

drains where outlets are suitable.

Use of proper stocking rates, pasture rotation, and

restricted grazing during wet periods helps to keep the

pasture in good condition. Proper grazing practices, weed

control, and fertilizer are needed for maximum quality of forage.

Legumes benefit from applications of agricultural lime. In

some years supplemental irrigation is needed.

This unit is suited to the production of red alder. On the

basis of a 50-year site curve, the mean site index is 106. The

mean annual increment at culmination (CMAI) for red alder at

age 40 is 128 cubic feet per acre. Among

the trees of limited extent are western redcedar, western

hemlock, and bigleaf maple. Among the common forest

understory plants are western swordfern, brackenfern, trailing

blackberry, thimbleberry, and salmonberry.

The main limitation for the harvesting of timber is seasonal

soil wetness. A seasonal high water table and ponding limit

the use of equipment to dry periods. Use of wheeled and

tracked equipment when the soil in this unit is wet produces

ruts, compacts the soil, and damages the roots of trees.

Unsurfaced roads and skid trails are soft when wet, and they

may be impassable. Logging roads require suitable

surfacing for year-round use. Rock for road construction is

not readily available on this unit.

Seedling mortality and brush competition are the main

limitations for the production of timber. If seed trees are

present, natural reforestation of cutover areas by red alder

occurs periodically. The seasonal high water table and

ponding reduce root respiration, which results in high

mortality of seedlings. When openings are made in the

canopy, invading brushy plants, if not controlled, can delay

reforestation. Because the rooting depth is restricted by the

seasonal high water table, trees are subject to windthrow.

This unit is poorly suited to urban development. It is

subject to ponding.

This map unit is in capability subclass IIIw.

40-Norma Variant loam. This very deep, poorly drained

soil is in depressional areas on outwash plains. It formed in

glacial outwash. Areas are 10 to 35 acres in size. The native

vegetation is mainly conifers and hardwoods. Elevation is 50

to 400 feet. Slope is 0 to 3 percent. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 180 to 200 days.

Typically, the surface layer is dark reddish brown loam

about 9 inches thick. The subsoil is light olive gray and

grayish brown sandy clay loam about 17 inches thick. The

substratum to a depth of 60 inches or more is olive gray

sandy loam and loamy sand. In some areas the surface

layer is silt loam and silty clay loam, and In some areas the

soil is somewhat poorly drained.

Included in this unit are areas of Bellingham, Custer, and

Norma soils and Terric Medisaprists in depressipnal areas

and Ragnar soils on outwash plains. Included areas

make up about 15 percent of the total acreage.

Permeability of this Norma Variant soil is moderately

slow. Available water capacity is moderate. Effective

rooting depth is limited by a seasonal high water table that is

at a depth of 0 to about 12 inches. Runoff is very slow, and

the hazard of water erosion is slight. Ponding occurs from

November to April.

This unit is used mainly for hay and pasture. It also is

used as woodland. Where drained, it is used as cropland

and for urban development.

This unit, where drained, is suited to use as cropland.

Proper row arrangement, field ditches, and vegetated
outlets are needed to remove excess water on the surface.

Tile drainage can be used to lower the water table if a

suitable outlet is available. In summer irrigation is

required for maximum production of most crops.

A suitable cropping system includes 1 or 2 years of

corn, 3 to 5 years of raspberries, and 3 to 5 years of

grasses and legumes. Growing vegetables and including an

annual winter cover crop is also suitable. Returning all

crop residue to the soil and using a cropping system that

includes grasses, legumes, or grass-legume mixtures help to

maintain fertility and tilth. Returning crop residue to the soil

also reduces compaction. Grain and grasses respond to

nitrogen; legumes respond to phosphorus, boron, sulfur, and

lime; and vegetables and berries respond to nitrogen,

phosphorus, and potassium.

This unit is suited to hay and pasture. Grazing when the

soil in this unit is wet results in compaction of the surface

layer, poor tilth, and excessive runoff. Excessive water on the

surface can be removed by tile drains if adequate outlets

are available. Use of proper stocking rates, pasture

rotation, and restricted grazing during wet periods helps to keep

the pasture in good condition.

Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing. Proper

grazing practices, weed control, and fertilizer are needed for

maximum quality of forage. Legumes benefit from

applications of agricultural lime. In some years

supplemental irrigation is needed.

Red alder is the main woodland species on this unit. On

the basis of a 50-year site curve, the estimated mean site

index is 60. The mean annual increment at culmination

(CMAI) for red alder is 50 cubic feet per acre at age 35.

Among the trees of limited extent is western redcedar.

Among the common forest understory plants are willow,

Oregon ash, sedge, and rose.

The main limitation for the harvesting of timber is seasonal

soil wetness, which limits the use of equipment to dry

periods. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid trails

are soft when wet, and they may be impassable. Logging

roads require suitable surfacing for year-round use. Rock for

road construction is not readily available on this unit.

Seedling mortality, windthrow hazard, and brush

competition are the main limitations for the production of

timber. If seed trees are present, natural reforestation of

cutover areas by red alder occurs periodically. A seasonal high

water table and ponding reduce root respiration, which

results in high seedling mortality. When openings are made in

the canopy, invading brushy plants, if not controlled, can

prevent reforestation. Because the rooting depth is restricted

by a seasonal high water table, trees are frequently subject

to windthrow.

The main limitation for homesites is the seasonal

ponding. Drainage is needed if roads and building

foundations are constructed. The main limitations for

septic tank absorption fields are the seasonal ponding,

moderately slow permeability in the subsoil, and seepage in the

substratum. Use of long absorption lines helps to

compensate for the moderately slow permeability. If the

density of housing is moderate to high, community

sewage systems are needed to prevent contamination of

water supplies as a result of seepage from onsite sewage

disposal systems.

This map unit is in capability subclass Illw.

41-Ogarty-Tokul-Rock outcrop complex, 65 to 90

percent slopes. This map unit is on foothills,

mountainsides, and till plains. Areas are 20 to 170 acres in

size. The native vegetation is mainly conifers. Elevation is 500 to

1,000 feet. The average annual precipitation is about 60

inches, the average annual air temperature is about 46

degrees F, and the average frost-free season is 140 to 180

days.

This unit is about 55 percent Ogarty very gravelly loam,

about 20 percent Tokul silt loam, and about 15 percent Rock

outcrop. The components of this unit are so intricately

intermingled that it was not practical to map them

separately at the scale used.

Included in this unit are small areas of Elwell and

Olomount soils on mountainsides and ridgetops. Also

included are talus slopes below areas of Rock outcrop.

Included areas make up about 10 percent of the total

acreage.

The Ogarty soil is moderately deep and moderately well

drained. It formed in volcanic ash and glacial till derived

dominantly from andesite. Typically, the surface is covered

with a mat of litter and decomposed material about 2 inches

thick. The surface layer, where mixed to a depth of about 6

inches, is dark brown very gravelly loam. The subsoil is dark

brown very gravelly loam and brown extremely gravelly loam

about 26 inches thick. The substratum is dark brown and

yellowish red extremely gravelly loam about 6 inches thick.

Andesite is at a depth of about 38 inches. Depth to andesite

ranges from 20 to 40 inches.

Permeability of the Ogarty soil is moderate. Available

water capacity is low. Effective rooting depth is 20 to 40

inches. Runoff is rapid, and the hazard of water erosion is

high.

The Tokul soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface is covered with a mat of leaves, twigs, and

decomposed litter about 2 inches thick. The surface layer is

dark brown gravelly loam about 4 inches thick. The subsoil is

brown, strong brown, and dark yellowish brown gravelly

loam about 18 inches thick. The substratum is light olive

brown gravelly fine sandy loam about 9 inches thick. A

hardpan is at a depth of 31 inches. Depth to the hardpan

ranges from 20 to 40 inches.

Permeability of the Tokul soil is moderate above the

hardpan and very slow through it. Available water

capacity is moderate. Effective rooting depth is limited by
a seasonal perched water table that is at a depth of 18 to

36 inches from November to May. Runoff is very rapid,

and the hazard of water erosion is very high.

Rock outcrop consists of areas where the surface is

exposed, unweathered andesite or argillite.

This unit is used mainly as woodland.

Douglas-fir and western hemlock are the main woodland

species on the Ogarty soil. On the basis of a 100-year site

curve, the mean site index is 150 for Douglas-fir and 169 for

western hemlock. On the basis of a 50-year site curve, the

mean site index is 117 for Douglas-fir and 115 for

western hemlock. The mean annual increment at culmination

(CMAI) is 158 cubic feet per acre for Douglas-fir at age 60 and

272 cubic feet per acre for western hemlock at age 50.

Douglas-fir and western hemlock are also the main woodland

species on the Tokul soil. On the basis of a 100-year site

curve, the mean site index is 173 for Douglas-fir and 166

for western hemlock. On the basis of a 50-year site curve,

the mean site index is 131 for Douglas-fir and 117 for

western hemlock. The mean annual increment at culmination

(CMAI) is 184 cubic feet per acre for Douglas-fir at age 60, and

266 cubic feet per acre for western hemlock at age 50. Rock

outcrop reduces yield by about 15 percent.

Among the trees of limited extent on this unit are western

redcedar, fir, red alder, and bigleaf maple. Among the common

forest understory plants are western swordfern,

brackenfern, red huckleberry, salal, and trailing blackberry.

The main limitations for the harvesting of timber are

steepness of slope and Rock outcrop. Cable yarding

systems generally are used on this unit. Harvesting systems that

lift logs entirely off the ground reduce the disturbance of the

protective layer of duff. Rock outcrop may cause breakage of

timber and hinder yarding operations. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is readily available

on this unit.

Establishing plant cover on steep road cut and fill slopes

reduces erosion. Following road construction and

clearcutting, road failures and landslides are likely to

occur.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily

and natural regeneration of western hemlock occurs

periodically. Rock outcrop limits the even distribution of

reforestation. When openings are made in the canopy,

invading brushy plants, if not controlled, can prevent

reforestation.

Because the rooting depth is restricted by the hardpan and

underlying bedrock, trees are subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly subject

to windthrow than are more deeply rooted trees.

This map unit is in capability subclass Vlle.

42-Olomount gravelly loam, 3 to 15 percent slopes.

This moderately deep, moderately well drained soil is on

mountainsides and ridgetops. It formed in glacial till,

volcanic ash, and weathered material derived dominantly

from andesite, argillite, and basalt. Areas are 20 to 60 acres in

size. The native vegetation is mainly conifers. Elevation is

800 to 1,800 feet. The average annual precipitation is

about 70 inches, the average annual air temperature is

about 44 degrees F, and the average frost-free season is

130 to 150 days.

Typically, the surface is covered with a mat of leaves,

needles, mosses, and partially decomposed litter about 3

inches thick. The surface layer is very dark grayish brown

gravelly loam about 2 inches thick. The subsoil is reddish

brown and dark brown gravelly loam about 16 inches thick.

The substratum is dark brown very gravelly loam and

extremely gravelly loam about 14 inches thick. Andesite is at

a depth of about 32 inches. Depth to andesite ranges from

20 to 40 inches.

Included in this unit are areas of Elwell soils, Rober soils

on terraces and terrace escarpments, and Rock outcrop.

Also included are some areas of soils that have andesite at

a depth of more than 40 inches. Included areas make up

about 15 percent of the total acreage.

Permeability of this Olomount soil is moderate.

Available water capacity is low. Effective rooting depth is 20

to 40 inches. Runoff is slow, and the hazard of water erosion

is slight. A seasonal high water table is at a depth of 18 to

36 inches from November to May.

This unit is used mainly as woodland, watershed, and

wildlife habitat.

Western hemlock is the main woodland species on this

unit. On the basis of a 100-year site curve, the mean site

index is 152. On the basis of a 50-year site curve, the mean

site index is 115. The mean annual increment at culmination

(CMAI) for western hemlock at age 50 is 241 cubic feet per

acre. Among the trees of limited extent are Douglas-fir,

western redcedar, Pacific silver fir, red alder, and bigleaf maple.

Among the common forest understory plants are

brackenfern, vine maple, deer fern, salmonberry, and salal.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment to

dry periods. Occasional snowpack also hinders harvesting.

Use of wheeled and tracked equipment when the soil in this

unit is wet produces ruts, compacts the soil, and damages

the roots of trees. Unsurfaced roads and skid trails are soft

when wet, and they may be impassable during rainy periods.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is readily available on this unit.

Windthrow hazard and brush competition are the main

limitations for the production of timber. If seed trees are

present, natural reforestation of cutover areas by western

hemlock occurs periodically. Reforestation can be

accomplished by planting Douglas-fir seedlings. When
openings are made in the canopy, invading brushy

plants, if not controlled, can delay reforestation.

Because the rooting depth is restricted by limited depth

to bedrock, trees are subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly

subject to windthrow than are more deeply rooted

trees.

The main limitations for homesites and septic tank

absorption fields are depth to rock and the seasonal high

water table. Deep cuts can expose bedrock. Drainage is

needed if roads and building foundations are constructed. Septic

tank absorption lines should be placed on the contour.

This map unit is in capability subclass IVe.

43-Olomount-Elwell-Rock outcrop complex, 65 to 90

percent slopes. This map unit is on mountainsides. The

native vegetation is mainly conifers. Elevation is 800 to

1,800 feet. The average annual precipitation is about 70

inches, the average annual air temperature is about 44

degrees F, and the average frost-free season is 130 to 150

days.

This unit is about 55 percent Olomount gravelly loam,

about 25 percent Elwell silt loam, and about 10 percent

Rock outcrop. The components of this unit are so intricately

intermingled that it was not practical to map them

separately at the scale used.

Included in this unit are areas of Rober soils on terraces

and terrace escarpments, Skykomish soils on terraces and

outwash plains, and talus slopes below the Rock outcrop.

Included areas make up about 10 percent of the total

acreage.

The Olomount soil is moderately deep and moderately

well drained. It formed in glacial till, volcanic ash, and

material derived dominantly from andesite, argillite, and

basalt. Typically, the surface is covered with a mat of leaves,

needles, mosses, and partially decomposed litter about 3

inches thick. The surface layer is very dark grayish brown

gravelly loam about 2 inches thick. The subsoil is reddish brown

and dark brown gravelly loam about 16 inches thick. The

substratum is dark brown very gravelly loam and extremely

gravelly loam about 14 inches thick. Andesite is at a depth of

about 32 inches. Depth to andesite ranges from 20 to 40

inches.

Permeability of the Olomount soil is moderate.

Available water capacity is low. Effective rooting depth is 20

to 40 inches. Runoff is very rapid, and the hazard of water

erosion is very high. A seasonal high water table is at a

depth of 18 to 36 inches from November to May.

The Elwell soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface layer is black silt loam about 2 inches thick. The

subsoil is strong brown, brown, and yellowish brown silt

loam about 21 inches thick. The substratum is pale olive

gravelly fine sandy loam about 4 inches thick. An olive,

weakly cemented hardpan is at a depth of about 27 inches.

Depth to the hardpan ranges from 20 to 40 inches.

Permeability of the Elwell soil is moderate to the hardpan

and very slow through it. Available water capacity is

moderate. Effective rooting depth is 20 to 40 inches. Runoff

is very rapid, and the hazard of water erosion is very high. A

seasonal perched water table is at a depth of 18 to 36

inches from November to June.

Rock outcrop consists of areas where 90 percent of the

surface is exposed, unweathered andesite or argillite. It

occurs as very steep cliffs.

This unit is used mainly as woodland, watershed, and

wildlife habitat.

Western hemlock is the main woodland species on the

Olomount soil. On the basis of a 100-year site curve, the

mean site index is 152. On the basis of a 50-year site curve,

the mean site index is 115. The mean annual increment at

culmination (CMAI) for western hemlock at age 50 is 241

cubic feet per acre.

Western hemlock is also the main woodland species on

the Elwell soil. On the basis of a 100-year site curve, the

mean site index is 152. On the basis of a 50-year site

curve, the mean site index is 108. The mean annual

increment at culmination (CMAI) for western hemlock at

age 50 is 241 cubic feet per acre. Rock outcrop in this unit

reduces yield by about 10 percent.

Among the trees of limited extent are Douglas-fir, western

redcedar, Pacific silver fir, red alder, and bigleaf maple.

Among the common forest understory plants are western

swordfern, red huckleberry, brackenfern, deer fern, salal, vine

maple, and salmonberry.

The main limitations for the harvesting of timber is

steepness of slope, seasonal soil wetness, and Rock

outcrop. Occasional snowpack also hinders harvesting.

Cable yarding systems generally are used on this unit.

Harvesting systems that lift logs entirely off the ground

reduce the disturbance of the protective layer of duff. Rock

outcrop may cause breakage of timber and hinder yarding

operations. Wetness limits the use of equipment to dry

periods.

Unsurfaced roads and skid trails are soft when wet, and

they may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is readily available on this unit. Establishing

plant cover on steep road cut and fill slopes reduces erosion.

Following road construction and clearcutting, road failures

and landslides are likely to occur. Steep yarding paths, skid

trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or they are

protected by plant cover.

Windthrow hazard and brush competition are the main

limitations for the production of timber. If seed trees are

present, natural reforestation of cutover areas by western

hemlock occurs periodically. Reforestation can be

accomplished by planting Douglas-fir seedlings. Rock

outcrop limits the even distribution of reforestation. When

openings are made in the canopy, invading brushy plants, if

not controlled, can delay reforestation.

Because the rooting depth is restricted by the hardpan and

underlying bedrock, trees are occasionally subject to
windthrow. Western hemlock, a shallow-rooted tree, is more

commonly subject to windthrow than are more deeply

rooted trees.

This map unit is in capability subclass Vlls.

44-Orcas peat. This very deep, very poorly drained soil is

in basins on hills. It formed in sphagnum moss. Areas are

10 to 40 acres in size. The native vegetation is mainly

sphagnum moss and herbaceous plants. Elevation is 100 to

500 feet. Slope is 0 to 2 percent. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frost-free

season is 160 to 180 days.

Typically, the upper layer is dark reddish brown organic

material about 3 inches thick. Below this to a depth of

60 inches or more is dark brown organic material. In some

areas the profile is woody peat.

Included in this unit are areas of Mukilteo soils and Terric

Medisaprists in depressional areas. Included areas make up

about 10 percent of the total acreage.

Permeability of this Orcas soil is very rapid. Available water

capacity is high. Effective rooting depth is limited by a high

water table that is at a depth of 0 to 12 inches. Runoff is

ponded.

This unit is used for wildlife habitat.

This unit serves as a nesting area for ducks, herons, and

other waterfowl. Plantings of smartweed, wild millet, or bulrush

encourage added populations. This map unit is in capability

subclass Vw.

45-Oso gravelly loam, 3 to 15 percent slopes. This

moderately deep, moderately well drained soil is on

mountainsides and ridgetops. It formed in glacial till, volcanic

ash, and material derived dominantly from andesite.

Areas are 20 to 50 acres in size. The native vegetation is

mainly conifers. Elevation is 1,800 to 2,600 feet. The average

annual precipitation is about 85 inches, the average annual air

temperature is about 43 degrees F, and the average frost-free

season is 90 to 120 days.

Typically, the surface is covered with a mat of leaves,

needles, twigs, and mosses about 2 inches thick. The

surface layer is black gravelly loam about 3 inches thick.

The subsurface layer is light brownish gray gravelly loam about 2

inches thick. The subsoil is dark brown and yellowish brown

gravelly loam about 24 inches thick. Andesite is at a depth of

about 29 inches. Depth to andesite ranges from 20 to 40

inches.

Included in this unit are small areas of soils that are more

than 35 percent coarse fragments and soils that have a

cobbly or stony surface layer. Also included are areas of

Getchell soils and Rock outcrop. Included areas make up

about 10 percent of the total acreage.

Permeability of this Oso soil is moderate. Available water

capacity is moderate. Effective rooting depth is 20 to 40

inches. Runoff is slow, and the hazard of water erosion is

slight. A seasonal perched water table is at a depth of 18 to

36 inches from November to May.

This unit is used as woodland and watershed and for

wildlife habitat.

Western hemlock is the main woodland species on

this unit. On the basis of a 100-year site curve, the mean site

index is 129. On the basis of a 50-year site curve, the mean

site index is 93. The mean annual increment at culmination

(CMAI) for western hemlock at age 50 is 198 cubic feet per

acre. Among the trees of limited extent are Pacific silver fir

and Douglas-fir. Among the common forest understory

plants are red huckleberry, trailing blackberry, blue-leaved

huckleberry, and bunchberry dogwood.

The main limitation for the harvesting of timber is seasonal

soil wetness, which restricts the use of equipment to dry

periods. Snowpack also limits the use of equipment and

restricts access. Use of wheeled and tracked equipment

when the soil in this unit is wet produces ruts, compacts the

soil, and damages the roots of trees. Unsurfaced roads and

skid trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable surfacing

for year-round use. Rock for road construction is readily

available on this unit.

Seedling establishment is the main limitation for the

production of timber. If seed trees are present, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. When openings are

made in the canopy, invading brushy plants, if not controlled,

can delay natural reforestation. Reforestation can be

accomplished by planting Douglas-fir seedlings. Because the

rooting depth is restricted by underlying bedrock, trees are

occasionally subject to windthrow.

The main limitations for homesites and septic tank

absorption fields are the depth to rock and the seasonal

perched water table. Deep cuts can expose bedrock.

Drainage is needed if buildings with basements and crawl

spaces are constructed. Septic tank absorption lines should

be placed on the contour.

This map unit is in capability subclass VIe.

46-Oso-Getchell-Rock outcrop complex, 65 to 90

percent slopes. This map unit is on mountainsides. Areas

are irregular in shape and are 10 to 200 acres in size. The

native vegetation is mainly conifers. Elevation is 1,800 to

2,600 feet. The average annual precipitation is about 90

inches, the average annual air temperature is about 43

degrees F, and the average frost-free season is 90 to 125

days.

This unit is about 55 percent Oso gravelly loam, about 25

percent Getchell silt loam, and about 10 percent Rock

outcrop. The components of this unit are so intricately

intermingled that it was not practical to map them separately

at the scale used.

Included in this unit are small areas of Potchub, Elwell,

Hartnit, and Olomount soils and Skykomish soils on terraces

and outwash plains. Included areas make up about 10

percent of the total acreage.

The Oso soil is moderately deep and moderately well

drained. It formed in glacial till, volcanic ash, and
material derived dominantly from andesite. Typically, the

surface is covered with a mat of leaves, needles, twigs,

and mosses about 2 inches thick. The surface layer is

black gravelly loam about 3 inches thick. The subsurface

layer is light brownish gray gravelly loam about 24 inches thick.

Andesite is at a depth of about 27 inches. Depth to andesite

ranges from 20 to 40 inches.

Permeability of the Oso soil is moderate. Available water

capacity is moderate. Effective rooting depth is 20 to 40

inches. Runoff is very rapid, and the hazard of water

erosion is very high. A seasonal perched water table is at a

depth of 18 to 36 inches from November to May.

The Getchell soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface is covered with a mat of needles, leaves,

twigs, and decomposed material about 2 inches thick. The

surface layer is black silt loam about 2 inches thick. The

subsoil is yellowish red, strong brown, light olive brown,

and dark brown silt loam about 34 inches thick. Olive,

dense glacial till is at a depth of about 36 inches. Depth to

glacial till ranges from 20 to 40 inches.

Permeability of the Getchell soil is moderate to the

glacial till and very slow through it. Available water capacity

is moderate. Effective rooting depth is 20 to 40 inches.

Runoff is very rapid, and the hazard of water erosion is

very high. A seasonal perched water table is at a depth of 18 to

36 inches from December to May. The effect of the layer of

dense glacial till on use and management is similar to that of a

hardpan.

Rock outcrop consists of areas where the surface is

exposed, unweathered andesite. It occurs as very steep

cliffs.

This unit is used mainly as woodland, watershed, and wildlife

habitat.

Western hemlock is the main woodland species on the

Oso soil. On the basis of a 100-year site curve, the

mean site index is 129. On the basis of a 50-year site

curve, the mean site index is 93. The mean annual increment at

culmination (CMAI) for western hemlock at age 50 is 198

cubic feet per acre.

Western hemlock is also the main woodland species

on the Getchell soil. On the basis of a 100-year site curve,

the mean site index is 130. On the basis of a 50-year site

curve, the mean site index is 90. The mean annual

increment at culmination (CMAI) for western hemlock at

age 50 is 200 cubic feet per acre. Rock

outcrop in this unit reduces yield by about 10 percent.

Among the trees of limited extent are Pacific silver fir,

Douglas-fir, and western redcedar. Among the common forest

understory plants are red huckleberry, deer fern,

brackenfern, devilsclub, ladyfern, trailing blackberry, blueleaved huckleberry, and bunchberry dogwood.

The main limitations for the harvesting of timber on this

unit are steepness of slope, seasonal soil wetness, and

Rock outcrop. Cable yarding systems generally are used on this

unit. Harvesting operations that lift logs entirely off the

ground reduce the disturbance of the

protective layer of duff. A seasonal high water table

limits the use of equipment to dry periods. Snowpack

also limits the use of equipment and restricts access.

Unsurfaced roads and skid trails are soft when wet, and

they may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is readily available on this unit. Following road

construction and clearcutting, road failures and landslides

are likely to occur. Establishing plant cover on steep road

cut and fill slopes reduces erosion. Steep yarding paths, skid

trails, and firebreaks are subject to rifling and gullying unless

adequate water bars are provided or they are protected by

plant cover.

Seedling establishment and windthrow hazard are the

main limitations for the production of timber. If seed trees

are present, natural reforestation of cutover areas by

western hemlock and Pacific silver fir occurs periodically.

Rock outcrop limits the even distribution of reforestation.

When openings are made in the canopy, invading brushy

plants, if not controlled, can delay reforestation.

Because the rooting depth is restricted by the

underlying bedrock and dense glacial till, trees are

occasionally subject to windthrow. Western hemlock, a

shallow-rooted tree, is more commonly subject to

windthrow than are more deeply rooted trees.

This map unit is in capability subclass VIIs.

47-Pastik silt loam, 0 to 8 percent slopes. This very

deep, moderately well drained soil is on terraces. It formed

in lake sediment and volcanic ash. Areas are 20 to 100

acres in size. The native vegetation is mainly conifers.

Elevation is 200 to 800 feet. The average annual

precipitation is about 50 inches, the average annual air

temperature is about 46 degrees F, and the average frostfree season is 140 to 200 days.

Typically, the surface layer is dark brown silt loam about

6 inches thick. The subsoil is dark brown and yellowish

brown silt loam about 23 inches thick. The substratum to a

depth of 60 inches or more is light olive gray silt loam. In

some areas the surface layer and subsoil are fine sandy

loam and loamy fine sand.

Included in this unit are areas of Bellingham soils in

depressional areas, Nargar soils on high terraces,

Ragnar soils on outwash plains, and Tokul soils on till

plains. Included areas make up about 15 percent of the

total acreage.

Permeability of this Pastik soil is slow. Available

water capacity is high. Effective rooting depth is limited by a

seasonal high water table that is at a depth of 18 to 30

inches from December to May. Runoff is slow, and the

hazard of water erosion is slight.

This unit is used mainly as woodland. It is also used for

hay and pasture and for urban development.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

180. On the basis of a 50-year site curve, the
mean site index is 135. The mean annual increment at

culmination (CMAI) for Douglas-fir at age 60 is 191 cubic feet per

acre. Among the trees of limited extent are western hemlock,

western redcedar, and bigleaf maple. Among the common

forest understory plants are western swordfern, brackenfern,

ladyfern, red huckleberry, and deer fern.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment

to dry periods. Use of wheeled and tracked equipment

when the soil in this unit is wet produces ruts, compacts the

soil, and damages the roots of trees. Unsurfaced roads and

skid trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable

surfacing for year-round use. Rock for road construction is

not readily available on this unit.

Reforestation can be accomplished by planting Douglas-fir

seedlings. If seed trees are present, natural reforestation of

cutover areas by red alder occurs readily. When openings are

made in the canopy, invading brushy plants, if not controlled,

can prevent reforestation. Because the rooting depth is

restricted by the seasonal high water table, trees are

occasionally subject to windthrow.

This unit is suited to hay and pasture. The main

limitations are slope and the seasonal high water table.

Grazing when the soil is wet results in compaction of the

surface layer, poor tilth, and excessive runoff. Excessive

water on the surface can be removed by tile drains if

adequate outlets are available. Use of proper stocking

rates, pasture rotation, and restricted grazing during wet periods

helps to keep the pasture in good condition and to protect

the soil from erosion.

Periodic mowing and clipping help to maintain uniform growth,

discourage selective grazing, and reduce clumpy growth. Proper

grazing practices, weed control, and fertilizer are needed for

maximum quality of forage. Legumes benefit from

applications of agricultural lime.

The main limitation for homesites is the seasonal high

water table. Wetness can be reduced by installing drain tile

around footings. The main limitations for septic tank

absorption fields are the seasonal high water table and

slow permeability. Use of long absorption lines helps to

compensate for the slow permeability. Disturbed areas

need to be seeded to grass. Temporary sediment basins

are needed where construction leaves soil areas bare of

cover.

This map unit is in capability subclass lIe.

48-Pastik silt loam, 8 to 25 percent slopes. This very

deep, moderately well drained soil is on terraces. It formed in

lake sediment and volcanic ash. Areas are 10 to 50 acres

in size. The native vegetation is mainly conifers. Elevation

is 200 to 800 feet. The average annual precipitation is

about 50 inches, the average annual air temperature is

about 46 degrees F, and the average frost-free season is

140 to 200 days.

Typically, the surface layer is dark brown silt loam

about 6 inches thick. The subsoil is dark brown and

yellowish brown silt loam about 23 inches thick. The

substratum to a depth of 60 inches or more is light olive

gray silt loam. In some areas the surface layer and subsoil

are fine sandy loam and loamy fine sand.

Included in this unit are areas of Nargar soils on high

terraces, Ragnar soils on outwash plains, and Tokul soils on

till plains. Included areas make up about 15 percent of the

total acreage.

Permeability of this Pastik soil is slow. Available water

capacity is high. Effective rooting depth is limited by a

seasonal high water table that is at a depth of 18 to 30

inches from December to May. Runoff is medium, and the

hazard of water erosion is moderate.

This unit is used mainly as woodland. It is also used for

hay and pasture and urban development.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

180. On the basis of a 50-year site curve, the mean site

index is 135. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 60 is 191 cubic feet per

acre. Among the trees of limited extent are western

hemlock, western redcedar, and bigleaf maple. Among the

common forest understory plants are western swordfern,

brackenfern, ladyfern, red huckleberry, and deer fern.

The main limitation for the harvesting of timber is seasonal

soil wetness, which limits the use of equipment to dry

periods. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable

surfacing for year-round use. Rock for road construction is

not readily available on this unit. Establishing plant cover on

steep road cut and fill slopes reduces erosion.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily.

When openings are made in the canopy, invading brushy

plants, if not controlled, can prevent reforestation. Because

the rooting depth is restricted by the high water table, trees

are occasionally subject to windthrow.

This unit is suited to hay and pasture. The main limitations

are the seasonal high water table and slope. Grazing when

the soil is wet results in compaction of the surface layer,

poor tilth, and excessive runoff. Excessive water on the

surface can be removed by tile drains if adequate outlets are

available.

Use of proper stocking rates, pasture rotation, and

restricted grazing during wet periods helps to keep the

pasture in good condition and to protect the soil from

erosion. Periodic mowing, spreading of droppings, and

clipping help to maintain uniform growth and discourage

selective grazing. Proper grazing practices, weed control,

and fertilizer are needed for maximum quality of forage.

Legumes benefit from applications of agricultural lime.
The main limitations for homesites are the seasonal

high water table and steepness of slope in areas where

slopes are more than 15 percent. Wetness can be reduced

by installing drain tile around footings. The hazard of erosion is

increased if the soil in this unit is left exposed during site

development. Areas where the soil is bare need to be seeded

to grass. Temporary sediment basins are needed where

construction leaves soil areas bare of cover. Topsoil should be

stockpiled and used to reclaim areas disturbed by cutting

and filling. Access roads must be designed to control

surface runoff and to help stabilize cut slopes.

The main limitations for septic tank absorption fields

are the seasonal high water table, slow permeability, and

steepness of slope in areas where slopes are more than

15 percent. Use of long absorption lines helps to compensate

for the slow permeability. Septic tank absorption lines should be

on the contour.

This map unit is in capability subclass Ille.

49-Pastik silt loam, 25 to 50 percent slopes. This very

deep, moderately well drained soil is on terraces. It formed

in lake sediment and volcanic ash. Areas are 10 to 70

acres in size. The native vegetation is mainly conifers.

Elevation is 200 to 800 feet. The average annual

precipitation is about 50 inches, the average annual air

temperature is about 46 degrees F, and the average frost-free

season is 140 to 200 days.

Typically, the surface layer is dark brown silt loam about 6

inches thick. The subsoil is dark brown and yellowish brown

silt loam about 23 inches thick. The substratum to a depth

of 60 inches or more is light olive gray silt loam. In some

areas the surface layer and subsoil are fine sandy loam and

loamy fine sand.

Included in this unit are areas of Nargar soils on high

terraces, Ragnar soils on outwash plains, and Tokul soils on till

plains. Included areas make up about 15 percent of the total

acreage.

Permeability of this Pastik soil is slow. Available water capacity

is high. Effective rooting depth is limited by a seasonal high

water table that is at a depth of 18 to 30 inches from

December to May. Runoff is rapid and the hazard of water

erosion is high.

This unit is used mainly as woodland.

Douglas-fir is the main woodland species on this unit. On

the basis of a 100-year site curve, the mean site index is

180. On the basis of a 50-year site curve, the mean site index

is 135. The mean annual increment at culmination (CMAI) for

Douglas-fir at age 60 is 191 cubic feet per acre. Among the trees

of limited extent are western hemlock, western redcedar, and

bigleaf maple. Among the common forest understory plants

are western swordfern, brackenfern, red huckleberry, and

deer fern.

The main limitations for the harvesting of timber are

steepness of slope and seasonal soil wetness.

Steepness of slope restricts the use of wheeled and

tracked equipment in skidding operations; cable yarding

systems generally are safer and disturb the soil less.

The seasonal high water table limits the use of equipment

to dry periods. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or they are protected by

plant cover. Unsurfaced roads and skid trails are soft when

wet, and they may be impassable during rainy periods.

Logging roads require suitable surfacing for year-round

use. Rock for road construction is not readily available on

this unit. Establishing plant cover on steep road cut and fill

slopes reduces erosion.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily.

When openings are made in the canopy, invading brushy

plants, if not controlled, can prevent reforestation. Because

the rooting depth is restricted by the high water table, trees

are occasionally subject to windthrow.

The main limitations for homesites are steepness of slope

and the seasonal high water table. Wetness can be reduced

by installing drain tile around footings. The main limitations

for septic tank absorption fields are the seasonal high water

table, slow permeability, and steepness of slope. The hazard

of erosion is increased if the soil in this unit is left exposed

during site development. Access roads must be designed to

control surface runoff and to help stabilize cut slopes. Topsoil

should be stockpiled and used to reclaim areas disturbed by

cutting and filling.

This map unit is in capability subclass VIe.

50-Pilchuck loamy sand. This very deep, somewhat

excessively drained soil is on flood plains. It formed in alluvium.

Areas are long and narrow and are 10 to 50 acres in size.

The native vegetation is mainly conifers and hardwoods.

Elevation is 20 to 800 feet. Slope is 0 to 3 percent. The

average annual precipitation is about 45 inches, the average

annual air temperature is about 50 degrees F, and the

average frost-free season is 160 to 200 days.

Typically, the surface layer, where mixed to a depth of

about 4 inches, is dark grayish brown loamy sand. The upper

part of the underlying material is black loamy sand about 27

inches thick. The next part is light gray fine sand about 19

inches thick. The lower part to a depth of 60 inches or more

is light gray gravelly sand.

Included in this unit are small areas of soils that have a

surface layer of loam, gravelly loam, or cobbly loam and

are gravelly or cobbly in the upper part of the substratum.

Also included are areas of Sultan soils, Puget soils in

depressional areas, and Puyallup soils on stream terraces.

Included areas make up about 15 percent of the total

acreage.

Permeability of this Pilchuck soil is rapid. Available

water capacity is low. Effective rooting depth is 60

inches or more. Runoff is very slow. A seasonal high

water table is at a depth of 24 to 48 inches from
November to April. Flooding is frequent from

November to April.

This unit is used mainly as woodland. It is also used

for pasture.

Douglas-fir is the main woodland species on this unit.

On the basis of a 100-year site curve, the mean site index is

152. On the basis of a 50-year site curve, the mean site

index is 115. The mean annual increment at culmination

(CMAI) for Douglas-fir at age 60 is 161 cubic feet per acre.

Among the trees of limited extent are black cottonwood,

red alder, and bigleaf maple. Among the common forest

understory plants are vine maple, western swordfern,

salmonberry, common snowberry, and false-Solomons-seal.

The main limitation for harvesting of timber is soil wetness.

Frequent seasonal flooding limits the use of equipment to dry

periods in summer. Logging roads require suitable surfacing

for year-round use. Damage to roads from flooding is likely.

Rock for road construction is not readily available on this

unit.

Seedling mortality and brush competition are the main

limitations for the production of timber. Reforestation can be

accomplished by planting Douglas-fir seedlings. If seed trees

are present, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, invading brushy plants, if not controlled, can delay

reforestation. Wetness reduces root respiration, which results

in high seedling mortality.

If this unit is used for pasture, the main limitations are the

low available water capacity, low soil fertility, and the

hazard of flooding. Use of proper stocking rates, pasture

rotation, and restricted grazing during wet periods helps to

keep the pasture in good condition. Proper grazing practices,

weed control, and fertilizer are needed for maximum quality of

forage. In some years supplemental irrigation is needed.

The main limitations for homesites are seasonal flooding and

wetness. Dikes and channels that have outlets to bypass

floodwater can be used to protect buildings. The main

limitations for septic tank absorption fields are the hazard

of flooding, wetness, and seepage. The soil material in

this unit is a poor filter for effluent from conventional septic

tank absorption fields.

This map unit is in capability subclass IVw.

51-Pits. This map unit consists of gravel pits, sand pits,

and rock quarries. Areas average 5 to 15 acres in size and

are irregular in shape. Elevation is 100 to 2,000 feet. About

50 percent of the pits mapped were in active use, and

about 50 percent were abandoned.

With proper reclamation, these areas can be

revegetated and improved for use as wildlife habitat.

This map unit is in capability subclass VIIIs.

52-Potchub silt loam, 3 to 30 percent slopes. This

moderately deep, moderately well drained soil is on

mountainsides and ridgetops. It formed in glacial till and

volcanic ash. Areas are irregular in shape and are 100 to

300 acres in size. The native vegetation is mainly conifers.

Elevation is 2,600 to 3,600 feet. The average annual

precipitation is about 90 inches, the average annual air

temperature is about 41 degrees F, and the average frostfree season is 90 to 100 days.

Typically, the surface is covered with a mat of leaves,

needles, twigs, and decomposed organic litter about 9

inches thick. The surface layer is very dark brown silt loam

about 7 inches thick. The subsurface layer is pinkish gray silt

loam about 3 inches thick. The subsoil is dark reddish

brown, strong brown, and dark brown silt loam about 24

inches thick. Olive, dense glacial till is at a depth of about 34

inches. Depth to glacial till ranges from 20 to 40 inches.

Included in this unit are areas of Getchell, Hartnit, and

Verlot soils and Cryohemists in depressional areas. Also

included are some areas of soils in which depth to glacial till

is more than 40 inches. Included areas make up about 15

percent of the total acreage.

Permeability of this Potchub soil is moderate to the

glacial till and very slow through it. Available water capacity

is moderate. Effective rooting depth is 20 to 40 inches.

Runoff is medium, and the hazard of water erosion is

moderate. A seasonal perched water table is at a depth of

18 to 36 inches from November to May. The effect of the

layer of dense glacial till on use and management is similar

to that of a hardpan.

This unit is used as woodland and watershed.

Western hemlock is the main woodland species on this

unit. On the basis of a 100-year site curve, the mean site

index is 68. On the basis of a 50-year site curve, the mean

site index is 56. The mean annual increment at culmination

(CMAI) for western hemlock at age 60 is 70 cubic feet per

acre. Among the trees of limited extent are Pacific silver fir

and Douglas-fir. Among the common forest understory

plants are red huckleberry, trailing blackberry, blue-leaved

huckleberry, bunchberry dogwood, and deer fern.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment to

dry periods. Snowpack also limits the use of equipment and

restricts access. Use of wheeled and tracked equipment

when the soil in this unit is wet produces ruts, compacts the

soil, and damages the roots of trees. Unsurfaced roads and

skid trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is not readily

available on this unit.

Establishing plant cover on steep road cut and fill

slopes reduces erosion. Disturbance of the protective

layer of duff can be reduced with the careful use of

wheeled and tracked equipment.

Seedling establishment is the main concern for the

production of timber. If seed trees are present, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. When openings

are made in the canopy, invading brushy plants, if not

controlled, can delay reforestation.
Because the rooting depth is restricted by the seasonal

perched water table and the glacial till, trees are

occasionally subject to windthrow. Western hemlock, a

shallow-rooted tree, is more commonly subject to

windthrow than are more deeply rooted trees.

This map unit is in capability subclass VIIe.

53-Potchub-Hartnit complex, 15 to 30 percent

slopes. This map unit is on mountainsides and ridgetops. Areas

are 30 to 120 acres in size. The native vegetation is mainly

conifers. Elevation is 2,600 to 3,600 feet. The average annual

precipitation is about 90 inches, the average annual air

temperature is about 41 degrees F, and the average frostfree season is 90 to 100 days.

This unit is about 60 percent Potchub silt loam and

about 25 percent Hartnit gravelly silt loam. The

components of this unit are so intricately intermingled

that it was not practical to map them separately at the

scale used.

Included in this unit are small areas of Getchell, Oso, and

Verlot soils and Cryohemists, nearly level, in depressional

areas. Included areas make up about 15 percent of the total

acreage.

The Potchub soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface is covered with a mat of leaves, needles, twigs,

and decomposed organic litter about 9 inches thick. The

surface layer is very dark brown silt loam about 7 inches

thick. The subsurface layer is pinkish gray silt loam about

3 inches thick. The subsoil is dark reddish brown, strong

brown, and dark brown silt loam about 24 inches thick.

Olive, dense glacial till is at a depth of about 34 inches.

Depth to glacial till ranges from 20 to 40 inches.

Permeability of the Potchub soil is moderate to the

glacial till and very slow through it. Available water capacity

is moderate. Effective rooting depth is 20 to 40 inches.

Runoff is medium, and the hazard of water erosion

ismoderate. A seasonal perched water table is at a depth

of 18 to 36 inches from November to May. The effect of the

layer of dense glacial till on use and management is

similar to that of a hardpan.

The Hartnit soil is moderately deep and moderately

well drained. It formed in glacial till, volcanic ash, and

material derived dominantly from andesite, argillite, and basalt.

Typically, the surface is covered with a mat of leaves,

needles, twigs, and decomposed material about7 inches thick..

The surface layer is black gravelly silt loam about 4 inches

thick. The subsurface layer is gray gravelly silt loam

about 3 inches thick. The subsoil is dark reddish brown,

strong brown, and dark brown gravelly silt loam about 20

inches thick. Andesite is at a depth of about 27 inches.

Depth to andesite ranges from 20 to 40 inches.

Permeability of the Hartnit soil is moderate. Available

water capacity is moderate. Effective rooting depth is 20 to

40 inches. Runoff is medium, and the hazard of water

erosion is moderate. A seasonal high water table is at a

depth of 18 to 40 inches from November to May.

This unit is used mainly as woodland and watershed.

Western hemlock is the main woodland species on the

Potchub soil. On the basis of a 100-year site curve, the

mean site index is 68. On the basis of a 50-year site curve,

the mean site index is 56. The mean annual increment at

culmination (CMAI) for western hemlock at age 60 is 70

cubic feet per acre.

Western hemlock is also the main woodland species on

the Hartnit soil. On the basis of a 100-year site curve, the

estimated mean site index is 60. On the basis of a 50-year

site curve, the estimated mean site index is 45. The

estimated mean annual increment at culmination (CMAI) for

western hemlock at age 70 is 57 cubic feet per acre.

Among the trees of limited extent on this unit are

Pacific silver fir and Douglas-fir. Among the common

forest understory plants are red huckleberry, trailing

blackberry, blue-leaved huckleberry, bunchberry

dogwood, and deer fern.

The main limitation for the harvesting of timber on this

unit is seasonal soil wetness, which limits the use of

equipment to dry periods. Snowpack also limits the use of

equipment and restricts access. Use of wheeled and tracked

equipment when the soils in this unit are wet produces ruts,

compacts the soils, and damages the roots of trees.

Unsurfaced roads and skid trails are soft when wet, and

they may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is readily available on this unit.

Establishing plant cover on steep road cut and fill

slopes reduces erosion. Disturbance of the protective

layer of duff can be reduced with the careful use of

wheeled and tracked equipment.

Seedling establishment is the main concern for the

production of timber. If seed trees are present, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. When openings

are made in the canopy, invading brushy plants, if not

controlled, can delay reforestation.

Because the rooting depth is restricted by the high

water table and limited depth to bedrock, trees are

occasionally subject to windthrow. Western hemlock, a

shallow-rooted tree, is more commonly subject to

windthrow than are more deeply rooted trees.

This map unit is in capability subclass VIIe.

54-Potchub-Hartnit-Rock outcrop complex, 30 to 65

percent slopes. This map unit is on mountainsides. Areas

are 20 to 200 acres in size. The native vegetation is mainly

conifers. Elevation is 2,600 to 3,600 feet. The average

annual precipitation is about 90 inches, the average annual

air temperature is about 41 degrees F, and the average

frost-free season is 90 to 100 days.

This unit is about 50 percent Potchub silt loam, about 25

percent Hartnit gravelly silt loam, and about 10
percent Rock outcrop. The components of this unit are so

intricately intermingled that it was not practical to map them

separately at the scale used.

Included in this unit are small areas of Getchell, Oso,

and Verlot soils on ridgetops and mountainsides. Included

areas make up about 15 percent of the total acreage.

The Potchub soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash.

Typically, the surface is covered with a mat of leaves,

needles, twigs, and decomposed organic litter about 9

inches thick. The surface layer is very dark brown silt

loam about 7 inches thick. The subsurface layer is pinkish

gray silt loam about 3 inches thick. The subsoil is dark

reddish brown, strong brown, and dark brown silt loam

about 24 inches thick. Olive, dense glacial till is at a depth

of about 34 inches. Depth to glacial till ranges from 20 to 40

inches.

Permeability of the Potchub soil is moderate to the

glacial till and very slow through it. Available water

capacity is moderate. Effective rooting depth is 20 to 40

inches. Runoff is medium, and the hazard of water

erosion is moderate. A seasonal high water table is at a

depth of 18 to 36 inches from November to May. The effect

of the layer of dense glacial till on use and management

is similar to that of a hardpan.

The Hartnit soil is moderately deep and moderately well

drained. It formed in glacial till, volcanic ash, and material

derived dominantly from andesite, argillite, and basalt. Typically,

the surface is covered with a mat of leaves, needles, twigs,

and decomposed material about 7 inches thick. The surface

layer is black gravelly silt loam about 4 inches thick. The

subsurface layer is gray gravelly silt loam about 3 inches

thick. The subsoil is dark reddish brown, strong brown, and

dark brown gravelly silt loam about 20 inches thick. Andesite

is at a depth of about 27 inches. Depth to andesite ranges

from 20 to 40 inches.

Permeability of the Hartnit soil is moderate. Available

water capacity is moderate. Effective rooting depth is 20 to

40 inches. Runoff is medium, and the hazard of water

erosion is moderate. A seasonal high water table is at a

depth of 18 to 40 inches from November to May.

Rock outcrop consists of areas where the surface is

exposed, very hard andesite or argillite. It occurs as very steep

cliffs.

This unit is used mainly as woodland and watershed.

Western hemlock is the main woodland species on the

Potchub soil. On the basis of a 100-year site curve, the

mean site index is 68. On the basis of a 50-year site curve,

the mean site index is 56. The mean annual increment at

culmination (CMAI) for western hemlock at age 60 is 70

cubic feet per acre.

Western hemlock is also the main woodland species on

the Hartnit soil. On the basis of a 100-year site curve, the

estimated mean site index is 60. On the basis of a 50-year

site curve, the estimated mean site index is 45. The

estimated mean annual increment at culmination

(CMAI) for western hemlock is 57 cubic feet per acre at

age 70.

Rock outcrop in this unit reduces yield by about 10

percent. Areas on ridgetops that are subject to strong,

persistent winds are less productive than are other areas of

the unit.

Among the trees of limited extent on this unit are

Pacific silver fir and Douglas-fir. Among the common

forest understory plants are red huckleberry, trailing

blackberry, blue-leaved huckleberry, bunchberry

dogwood, and deer fern.

The main limitations for the harvesting of timber on this

unit are steepness of slope, seasonal soil wetness, and

Rock outcrop. Steepness of slope restricts the use of

wheeled and tracked equipment in skidding operations; cable

yarding systems generally are safer and disturb the soils less.

The seasonal high water table limits the use of equipment to

dry periods. Unsurfaced roads and skid trails are soft when

wet, and they may be impassable during rainy periods.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is readily available on this unit.

Rock outcrop may hinder yarding operations. Snowpack

limits the use of equipment and restricts access. Steep

yarding paths, skid trails, and firebreaks are subject to rilling

and gullying unless adequate water bars are provided or

they are protected by plant cover. Disturbance of the

protective layer of duff can be reduced with the careful use

of wheeled and tracked equipment.

Seedling establishment is the main limitation for the

production of timber. If seed trees are present, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. Rock outcrop limits the

even distribution of reforestation. When openings are made

in the canopy, invading brushy plants, if not controlled, can

delay reforestation.

Because the rooting depth is restricted by the high water

table and limited depth to bedrock, trees are occasionally

subject to windthrow. Western hemlock, a shallow-rooted

tree, is more commonly subject to windthrow than are

more deeply rooted trees.

This map unit is in capability subclass VIIe.

55-Puget silty clay loam. This very deep soil is in

depressional areas on flood plains. It has been artificially

drained. The soil formed in alluvium. Areas are 40 to 200

acres in size. The native vegetation is mainly hardwoods.

Elevation is near sea level to 650 feet. Slope is 0 to 2

percent. The average annual precipitation is about 40 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free season is 180 to 200 days.

Typically, the surface layer is dark grayish brown silty

clay loam about 9 inches thick. The underlying material to a

depth of 60 inches or more is olive gray and gray silty clay

loam. In some areas the soil is not drained and is not protected

from flooding.
Included in this unit are areas of Snohomish, Sumas, Sultan,

and Pilchuck soils on flood plains and Puyallup soils on stream

terraces. Included areas make up about 15 percent of the total

acreage.

Permeability of this Puget soil is slow. Available water

capacity is high. Effective rooting depth is 60 inches or

more. Runoff is slow, and the hazard of water erosion is

slight. A seasonal high water table is at a depth of 24 to 48

inches from November to April. This soil is partially

protected from flooding; however, rare periods of flooding

occur from December to March.

This unit is used mainly as cropland and for homesite

development. A few areas are used for woodland.

Where this unit is drained and protected from flooding, it is

suited to use as cropland. It is limited mainly by the seasonal

high water table. Proper row arrangement, field ditches, and

vegetated outlets are needed to remove excess surface

water. Tile drainage can be used to lower

the water table if a suitable outlet is available. Flooding

can be controlled by the use of levees and dikes. In summer,

irrigation is required for maximum production of most crops.

A suitable cropping system is one that includes 1 to 3

years of peas, cauliflower, cabbage, corn, or strawberries and 3

or 4 years of hay and pasture (fig. 3). Returning all crop

residue to the soil and using a cropping system that

includes grasses, legumes, or grass-legume mixtures help to

maintain fertility and tilth. Compaction can also be reduced

by returning crop residue to the soil. Grain and grasses

respond to nitrogen; legumes respond to phosphorus, boron,

sulfur, and lime; and vegetables and berries respond to nitrogen,

phosphorus, and potassium.

This unit is suited to use as woodland. On the basis of a

50-year site curve, the estimated mean site index for red

alder is 95. The estimated mean annual increment at

culmination (CMAI) for red alder at 40 years of age is

Figure 3.-Irrigated cabbage for seed on Puget silty clay loam.
109 cubic feet per acre. Other suitable trees include

black cottonwood, Sitka spruce, western redcedar, and

Douglas-fir.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment to dry

periods. Use of wheeled and tracked equipment when

the soil in this unit is wet produces ruts, compacts the soil,

and damages the roots of trees. Unsurfaced roads and skid

trails are sticky, and they may be impassable during rainy

periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is not readily

available on this unit.

Reforestation can be accomplished by planting Douglasfir seedlings. If seed trees are present, natural reforestation

of cutover areas by red alder occurs readily. Because the

rooting depth is restricted by the seasonal high water table, trees

are occasionally subject to windthrow.

The main limitations for homesites are the hazard of

flooding and seasonal soil wetness. Dikes and channels

that have outlets to bypass floodwater can be used to

protect buildings and onsite sewage disposal systems from

flooding. Wetness can be reduced by installing drain tile

around footings.

The main limitations for septic tank absorption fields

are wetness and slow permeability. Use of long

absorption lines helps to compensate for the slow

permeability.

This map unit is in capability subclass Ilw.

56-Puyallup fine sandy loam. This very deep, well

drained soil is on stream terraces. It formed in alluvium of

mixed origin. Areas are 10 to 40 acres in size. The native

vegetation is mainly conifers and hardwoods. Elevation is

20 to 500 feet. Slope is 0 to 3 percent. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frost-free

season is 150 to 200 days.

Typically, the surface layer is very dark grayish brown fine

sandy loam about 10 inches thick. The upper part of the

underlying material is dark grayish brown and olive brown

fine sandy loam about 20 inches thick. The lower part to a

depth of 60 inches or more is dark grayish brown sand. In

some areas the surface layer is loam and sandy loam.

Included in this unit are areas of Puget soils in

depressional areas on flood plains and Pilchuck, Sultan, Sultan

Variant, and Sumas soils on flood plains. Included areas make up

about 15 percent of the total acreage.

Permeability of this Puyallup soil is moderately rapid.

Available water capacity is moderate. Effective rooting

depth is 60 inches or more. Runoff is slow, and the

hazard of water erosion is slight. Rare periods of

flooding occurs from November to April.

This unit is used mainly as cropland and for hay and

pasture and homesite development. A few areas are

used as woodland.

This unit is well suited to use as cropland. The main

limitation is the moderate available water capacity. In

summer supplemental irrigation is required for maximum

production of most crops. A suitable cropping system is one

that includes 3 or 4 years of strawberries, sweet corn, snap

beans, or green peas and 2 to 4 years of hay and pasture.

Annual cropping with vegetables and growing a winter cover

crop to be used as green manure is also a suitable cropping

system.

Returning all crop residue to the soil and using a cropping

system that includes grasses, legumes, or grass-legume

mixtures help to maintain fertility and tilth. Grain and grasses

respond to nitrogen; legumes respond to phosphorus, boron,

sulfur, and lime; and vegetables and berries respond to

nitrogen, phosphorus, and potassium.

This unit is suited to hay and pasture. The main limitation

is the moderate available water capacity. In some years

supplemental irrigation is needed. The use of proper

stocking rates, pasture rotation, and restricted grazing

during wet periods helps to keep the pasture in good

condition. Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing.

Fertilizer is needed for optimum growth of grasses and

legumes. Legumes also benefit from applications of

agricultural lime.

This unit is suited to use as woodland. On the basis of a

100-year site curve, the estimated mean site index for

Douglas-fir is 170. On the basis of a 50-year site curve, the

estimated mean site index for Douglas-fir is about 115. On

the basis of a 50-year site curve, the estimated mean site

index for red alder is about 85. The estimated mean annual

increment at culmination (CMAI) is about 159 cubic feet per

acre for Douglas-fir at about 60 years of age and about 92

cubic feet per acre for red alder at about 40 years of age.

The main limitation for the harvesting of timber is the

hazard of flooding. Use of wheeled and tracked equipment

when the soil in this unit is wet produces ruts, compacts the

soil, and damages the roots of trees. Unsurfaced roads and

skid trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable

surfacing for year-round use. Rock for road construction is

not readily available on this unit.

Brush competition is the main concern in the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily.

The main limitation for homesites is the hazard of

flooding. Dikes and channels that have outlets to bypass

floodwater can be used to protect buildings. Cutbanks are

not stable and are subject to caving in. The main limitation

for septic tank absorption fields is seepage. If the density of

housing is moderate to high, community sewage systems

may be needed to prevent contamination of water supplies

as a result of seepage from onsite sewage disposal

systems.
This map unit is in capability subclass Ils.

57-Ragnar fine sandy loam, 0 to 8 percent slopes.

This very deep, well drained soil is on outwash plains. It

formed in glacial outwash. Areas are 10 to 40 acres in size.

The native vegetation is mainly conifers. Elevation is 300 to

1,000 feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and the average frost-free season is 180 to

200 days.

Typically, the surface is covered with a mat of partially

decomposed leaves, needles, and twigs about 2 inches thick.

The surface layer is dark brown fine sandy loam about 2

inches thick. The subsoil is dark brown and brown sandy

loam about 22 inches thick. The substratum to a depth of 60

inches or more is dark yellowish brown and dark gray loamy

sand and sand. In some areas the surface layer is loamy,

the subsoil is gravelly, and the substratum is very gravelly.

Included in this unit are areas of Everett, Indianola,

Pastik, and Winston soils on terraces and outwash plains.

Included areas make up about 15 percent of the total

acreage.

Permeability of this Ragnar soil is moderately rapid. Available

water capacity is moderate. Effective rooting depth is 60

inches or more. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used mainly for homesite development. It is also

used as cropland, hay and pasture, and woodland.

Douglas-fir and western hemlock are the main woodland

species on this unit. On the basis of a 100year site curve, the

mean site index is 165 for Douglas-fir and 159 for western

hemlock. On the basis of a 50-year site curve, the mean

site index is 125 for Douglas-fir and 112 for western

hemlock. The mean annual increment at culmination

(CMAI) is 176 cubic feet per acre for Douglas-fir at age 60

and 252 cubic feet per acre for western hemlock at age 50.

Among the trees of limited extent are red alder and

western redcedar. Among the common forest understory

plants are western swordfern, brackenfern, Oregon-grape,

salal, and huckleberry.

This unit is well suited to year-round logging; however, logging

roads require suitable surfacing for year-round use.

Seedling establishment is the main concern in the

production of timber. Reforestation can be accomplished by

planting Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by Douglas fir and red alder

occurs readily. When openings are made in the canopy,

invading brushy plants, if not controlled, can delay the

establishment of seedlings. The droughtiness of the

surface layer reduces the survival of seedlings.

This unit is suited to hay and pasture. The main

limitation is moderate available water capacity. Use of proper

stocking rates, pasture rotation, and restricted grazing

during wet periods helps to keep the pasture in

good condition. Periodic mowing and spreading of droppings help

to maintain uniform growth and discourage selective grazing.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. In some years

supplemental irrigation is needed. Legumes benefit from

applications of agricultural lime.

This unit is suited to use as cropland. A suitable cropping

system is strawberries, sweet corn, or peas for 3 or 4

years and grasses and legumes for 3 to 5 years. Returning

all crop residue to the soil and using a cropping system that

includes grasses, legumes, or grass-legume mixtures help to

maintain fertility and tilth. Grain and grasses respond to

nitrogen; legumes respond to phosphorous, boron, sulfur and

lime; and vegetables and berries respond to nitrogen,

phosphorus, and potassium. Fall tillage or seeding should be

across the slope or on the contour.

This unit has few limitations for homesites. The main

limitation for septic tank absorption fields is seepage in the

substratum. If the density of housing is moderate to high,

community sewage systems may be needed to prevent

contamination of water supplies as a result of seepage from

onsite sewage disposal systems. Cutbanks are not stable and

are subject to caving in.

This map unit is in capability subclass Ille.

58-Ragnar fine sandy loam, 8 to 15 percent slopes.

This very deep, well drained soil is on outwash plains. It

formed in glacial outwash. Areas are 10 to 40 acres in size.

The native vegetation is mainly conifers. Elevation is 300 to

1,000 feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and-the average frost-free season is 180 to 200

days.

Typically, the surface is covered with a mat of partially

decomposed leaves, needles, and twigs about 2 inches

thick. The surface layer is dark brown fine sandy loam about

2 inches thick. The subsoil is dark brown and brown sandy

loam about 22 inches thick. The substratum to a depth of 60

inches or more is dark yellowish brown and dark gray

loamy sand and sand.

Included in this unit are small areas of soils that have a

loamy sand surface layer, a gravelly subsoil, and a very

gravelly substratum. Also included are areas of Everett,

Indianola, Pastik, and Winston soils on terraces. Included

areas make up about 15 percent of the total acreage.

Permeability of this Ragnar soil is moderately rapid.

Available water capacity is low. Effective rooting depth is 60

inches or more. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used mainly as woodland. It is also used for

hay and pasture and for homesite development.

Douglas-fir and western hemlock are the main woodland

species on this unit. On the basis of a 100-year site curve,

the mean site index is 165 for Douglas-fir and 159 for

western hemlock. On the basis of a 50-year
site curve, the mean site index is 125 for Douglas-fir and

112 for western hemlock. The mean annual increment at

culmination (CMAI) is 176 cubic feet per acre for

Douglas-fir at age 60 and 252 cubic feet per acre for western

hemlock at age 50. Among the trees of limited extent are

red alder and western redcedar. Among the common

forest understory plants are western swordfern, brackenfern,

Oregon-grape, salal, and huckleberry.

This unit is well suited to year-round logging. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

Seedling establishment is the main concern in the

production of timber. Reforestation can be accomplished

by planting Douglas-fir seedlings. If seed trees are present,

natural reforestation of cutover areas by Douglas-fir and

red alder occurs readily. When openings are made in the

canopy, invading brushy plants, if not controlled, can

delay the establishment of seedlings. The droughtiness

of the surface layer reduces the survival of seedlings,

especially on south- and southwest-facing slopes.

This unit is suited to hay and pasture. The main

limitation is the moderate available water capacity. Use of proper

stocking rates, pasture rotation, and restricted grazing

during wet periods helps to keep the pasture in good

condition and to protect the soil from erosion. Periodic

mowing and spreading of manure help to maintain uniform

growth and discourage selective grazing. Proper grazing

practices, weed control, and fertilizer are needed for maximum

quality of forage. In some years supplemental irrigation is

needed. Legumes benefit from applications of agricultural

lime.

The main limitation for homesites is steepness of slope,

and the main limitation for septic tank absorption fields

is seepage in the substratum. If the density of housing is

moderate to high, community sewage systems may be

needed to prevent contamination of water supplies as a

result of seepage from onsite sewage disposal systems.

Cutbanks are not stable and are subject to caving in.

This map unit is in capability subclass Ille.

59-Riverwash. This map unit is on flood plains along

streams. It formed in recent alluvium consisting of sand,

gravel, cobbles, and stones. It is very deep and somewhat

excessively drained. Areas are long and narrow and are 5 to 20

acres in size. This unit supports little if any vegetation.

Elevation is 30 to 1,000 feet. The average annual

precipitation is about 50 inches, the average annual air

temperature is about 49 degrees F, and the average frost-free

season is 130 to 180 days.

Texture of the soil material and the content of gravel,

cobbles, and stones vary widely within short distances.

Included in this unit are small areas of sand bars. Also

included are areas of Pilchuck soils. Included areas make

up about 30 percent of the total acreage.

Riverwash is subject to frequent flooding. Overflow

and alteration by severe erosion and deposition are

frequent.

Some areas of this unit are suitable as a source of

sand and gravel.

This map unit is in capability subclass VIlIw.

60-Rober silt loam, 0 to 15 percent slopes. This very

deep, moderately well drained soil is on terraces and

terrace escarpments. It formed in lacustrine sediment.

Areas are 25 to 75 acres in size. The native vegetation is

mainly conifers. Elevation is 800 to 1,800 feet. The

average annual precipitation is about 70 inches, the

average annual air temperature is about 44 degrees F,

and the average frost-free season is 130 to 150 days.

Typically, the surface is covered with a mat of leaves,

needles, mosses, and partially decomposed litter about 4

inches thick. The surface layer is very dark brown silt loam

about 3 inches thick. The subsoil is dark reddish brown,

reddish brown, and yellowish brown silt loam about 19

inches thick. The substratum to a depth of 60 inches or

more is grayish brown, stratified silt loam and silty clay loam.

In some areas the surface layer is stony.

Included in this unit are small areas of granite Rock

outcrop. Also included are small areas of Bellingham

Variant soils in drainageways, Elwell soils on mountainsides

and ridgetops, and Skykomish soils on terraces and

outwash plains. Included areas make up about 15

percent of the total acreage.

Permeability of this Rober soil is slow. Available water

capacity is high. Effective rooting depth is limited by a

seasonal perched water table that is at a depth of 24 to 40

inches from December to May. Runoff is slow, and the

hazard of water erosion is slight.

This unit is used mainly as woodland. It is also used for

homesite development.

Western hemlock is the main woodland species on this

unit. On the basis of a 100-year site curve, the mean site

index is 156. On the basis of a 50-year site curve, the mean

site index is 111. The mean annual increment at culmination

(CMAI) for western hemlock at age 50 is 248 cubic feet per

acre.

Among the trees of limited extent are Douglas-fir and

western redcedar. Among the common forest understory

plants are western swordfern, brackenfern, ladyfern, red

huckleberry, and Oregon-grape.

The main limitation for the harvesting of timber is seasonal

soil wetness, which limits the use of equipment to dry

periods. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Disturbance of the protective

layer of duff can be reduced with the careful use of wheeled

and tracked equipment. Unsurfaced roads and skid trails are

soft when wet, and they may be impassable during rainy

periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is not readily

available on this unit.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are
present, natural reforestation of cutover areas by western

hemlock occurs readily. When openings are made in the

canopy, invading brushy plants, if not controlled, can

prevent reforestation.

Because the rooting depth is restricted by the seasonal

perched water table, trees are occasionally subject to

windthrow. Western hemlock, a shallow-rooted tree, is more

commonly subject to windthrow than are more deeply rooted

trees.

The main limitation for homesites is the seasonal high

water table. Wetness can be reduced by installing drain tile

around footings. The main limitations for septic tank

absorption fields are the seasonal high water table and slow

permeability. Septic tank absorption fields do not function

properly during rainy periods because of wetness. Use of long

absorption lines helps to compensate for the slow

permeability.

This map unit is in capability subclass lVe.

61-Rober silt loam, 15 to 30 percent slopes. This

very deep, moderately well drained soil is on terraces and

terrace escarpments. It formed in lacustrine sediment.

Areas are 10 to 50 acres in size. The native vegetation is

mainly conifers. Elevation is 800 to 1,800 feet. The

average annual precipitation is about 70 inches, the

average annual air temperature is about 44 degrees F,

and average frost-free season is 130 to 150 days.

Typically, the surface is covered with a mat of leaves,

needles, mosses, and partially decomposed litter about 4

inches thick. The surface layer is very dark brown silt loam

about 3 inches thick. The subsoil is dark reddish brown,

reddish brown, and yellowish brown silt loam about 19

inches thick. The substratum to a depth of 60 inches or

more is grayish brown, stratified silt loam and silty clay

loam. In some areas the surface layer is stony.

Included in this unit are small areas of granite Rock

outcrop. Also included are areas of Elwell soils on

mountainsides and plateaus and Skykomish soils on terraces

and outwash plains. Included areas make up about 15

percent of the total acreage.

Permeability of this Rober soil is slow. Available water

capacity is high. Effective rooting depth is limited by a

seasonal perched water table that is at a depth of 24 to 40

inches from December through May. Runoff is medium,

and the hazard of water erosion is moderate. This soil is

subject to hillside slippage.

This unit is used mainly as woodland. It is also used for

homesite development.

Western hemlock is the main woodland species on this

unit. On the basis of a 100-year site curve, the mean site

index is 156. On the basis of a 50-year site curve, the mean

site index is 111. The mean annual increment at culmination

(CMAI) for western hemlock at age 50 is 248 cubic feet per

acre. Among the trees of limited extent are Douglas-fir and

western redeedar. Among the common forest understory plants

are western swordfern, brackenfern, ladyfern, red

huckleberry, and Oregon-grape.

The main limitation for the harvesting of timber is

seasonal soil wetness, which restricts the use of equipment

to dry periods. Use of wheeled and tracked equipment when

the soil in this unit is wet produces ruts, compacts the soil,

and damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable surfacing

for year-round use. Rock for road construction is not readily

available on this unit.

Establishing plant cover on steep road cut and fill

slopes reduces erosion. Disturbance of the protective

layer of duff can be reduced with the careful use of

wheeled and tracked equipment.

Plant competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by western hemlock occurs

readily. When openings are made in the canopy, invading

brushy plants, if not controlled, can prevent reforestation.

Because the rooting depth is restricted by the perched

water table, trees are occasionally subject to windthrow.

Western hemlock, a shallow-rooted tree, is more commonly

subject to windthrow than are more deeply rooted trees.

The main limitations for homesites are steepness of slope,

hillside slippage, and wetness. Wetness can be reduced by

installing drain tile around footings. The main limitations for

septic tank absorption fields are the seasonal high water

table, slow permeability, and steepness of slope. Septic tank

absorption fields do not function properly during rainy

periods because of wetness. Use of long absorption lines

helps to compensate for the slow permeability. Disturbed

areas need to be seeded to grass to control erosion.

This map unit is in capability subclass lVe.

62-Rober silt loam, 30 to 65 percent slopes. This very

deep, moderately well drained soil is on terrace

escarpments. It formed in lacustrine sediment. Areas are 20

to 150 acres in size. The native vegetation is mainly

conifers. Elevation is 800 to 1,800 feet. The average annual

precipitation is about 70 inches, the average annual air

temperature is about 44 degrees F, and the average frostfree season is 130 to 150 days.

Typically, the surface is covered with a mat of leaves,

needles, mosses, and partially decomposed litter about 4

inches thick. The surface layer is very dark brown silt loam

about 3 inches thick. The subsoil is dark reddish brown,

reddish brown, and yellowish brown silt loam about 19

inches thick. The substratum to a depth of 60 inches or

more is grayish brown, stratified silt loam and silty clay

loam. In some areas the surface layer is stony.

Included in this unit are small areas of granite Rock

outcrop. Also included are areas of Elwell soils on

mountainsides and ridgetops and Skykomish soils on

terraces and outwash plains. Included areas make up

about 15 percent of the total acreage.
Permeability of this Rober soil is slow. Available water

capacity is high. Effective rooting depth is limited by a

seasonal perched water table that is at a depth of 24 to 40

inches from December to May. Runoff is rapid, and the

hazard of water erosion is high. This soil is subject to

hillside slippage.

This unit is used mainly as woodland.

Western hemlock is the main woodland species on this unit.

On the basis of a 100-year site curve, the mean site index

is 156. On the basis of a 50-year site curve, the mean site

index is 111. The mean annual increment at culmination (CMAI)

for western hemlock at age 50 is 248 cubic feet per

acre.

Among the trees of limited extent are Douglas-fir and western

redcedar. Among the common forest understory plants are

western swordfern, brackenfern, ladyfern, red huckleberry,

and Oregon-grape.

The main limitations for the harvesting of timber are

steepness of slope and seasonal soil wetness, which restricts

the use of equipment to dry periods. When harvesting

timber, steepness of slope restricts the use of wheeled and

tracked equipment in skidding operations; cable yarding

systems generally are safer and disturb the soil less.

Unsurfaced roads and skid trails are soft when wet,

and they may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit. Steep yarding

paths, skid trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or they are protected

by plant cover. Establishing plant cover on steep road

cut and fill slopes reduces erosion.

Plant competition is the main limitation in the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by western hemlock occurs readily.

When openings are made in the canopy, invading brushy plants, if

not controlled, can prevent reforestation.

Because the rooting depth is restricted by the perched

water table, trees are occasionally subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly subject to

windthrow than are more deeply rooted trees.

This map unit is in capability subclass VIle.

63-Skykomish gravelly loam, 0 to 30 percent

slopes. This very deep, somewhat excessively drained soil is

on terraces, terrace escarpments, and outwash plains. It

formed in glacial outwash and volcanic ash. Areas are 10

to 40 acres in size. The native vegetation is mainly

conifers. Elevation is 400 to 1,600 feet. The average

annual precipitation is about 65 inches, the average

annual air temperature is about 47 degrees F, and the

average frost-free season is 85 to 125 days.

Typically, the surface is covered with a mat of leaves,

twigs, and decomposed litter about 4 inches thick. The

surface layer is dark reddish brown and yellowish red gravelly

loam about 12 inches thick. The subsoil is yellowish red

very gravelly fine sandy loam about 7 inches thick. The

substratum to a depth of 60 inches or more is dark

yellowish brown and very dark grayish brown extremely

gravelly loamy coarse sand and extremely gravelly coarse

sand. In some areas the surface layer is gravelly sandy loam.

Included in this unit are areas of Elwell and Olomount soils

on mountainsides and ridgetops and Rober soils on

terraces and terrace escarpments. Also included are areas

of soils, on terrace escarpments, that have slopes of more

than 30 percent. Included areas make up about 15 percent

of the total acreage.

Permeability of this Skykomish soil is moderately rapid to the

substratum and very rapid through it. Available water

capacity is low. Effective rooting depth is 60 inches or

more. Runoff is slow, and the hazard of water erosion is

slight.

This unit is used mainly as woodland, watershed, and wildlife

habitat. It is also used for homesite development.

Western hemlock is the main woodland species on this

unit. On the basis of a 100-year site curve, the mean site

index is 152. On the basis of a 50-year site curve, the mean

site index is 106. The mean annual increment at

culmination (CMAI) for western hemlock at age 50 is 241

cubic feet per acre.

Among the trees of limited extent are Douglas-fir,

western redcedar, and red alder. Among the common

forest understory plants are red huckleberry, western

swordfern, brackenfern, salmonberry, and deer fern.

The main limitation for the harvesting of timber is seasonal

soil wetness. Use of wheeled and tracked equipment when

the soil in this unit is wet produces ruts, compacts the soil,

and damages the roots of trees. Occasional snowpack

hinders the use of equipment. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is readily available on

this unit. Disturbance of the protective layer of duff can be

reduced with the careful use of wheeled and tracked

equipment.

Seedling mortality and brush competition are the main

limitations for the production of timber. Reforestation can be

accomplished by planting Douglas-fir seedlings. If seed

trees are present, natural reforestation of cutover areas by

western hemlock occurs periodically. The droughtiness of the

surface layer reduces the survival of seedlings,

especially on south- and southwest-facing slopes. If

openings are made in the canopy, invading brushy plants can

delay reforestation.

The main limitation for homesites is steepness of slope,

and the main limitations for septic tank absorption fields are

steepness of slope and seepage. If the density of housing

is moderate to high, community sewage systems may be

needed to prevent contamination of water supplies as a

result of seepage from onsite
sewage disposal systems. Cutbanks are not stable and are

subject to caving in.

This map unit is in capability subclass IVe.

64-Snohomish silt loam. This very deep soil is on flood

plains. The soil has been artificially drained. It formed in

alluvium underlain by peat and muck. Areas .are 10 to 40 acres in

size. The native vegetation is mainly hardwoods. Elevation is

50 to 150 feet. Slope is 0 to 2 percent. The average annual

precipitation is about 40 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 180 to 200 days.

Typically, the surface layer is very dark grayish brown silt loam

about 6 inches thick. The subsoil is gray and very dark grayish

brown silty clay loam about 23 inches thick. Below this to a

depth of 60 inches or more is dark reddish brown, very dark

grayish brown, and very dark gray organic material. Depth to

organic material ranges from 17 to 32 inches. In some areas

the surface layer is silty clay loam or the soil is not

artificially drained.

Included in this unit are areas of Sumas soils, Mukilteo soils in

depressional areas, and Puget soils in depressional areas on flood

plains. Included areas make up about 15 percent of the total

acreage.

Permeability of this Snohomish soil is slow. Available water

capacity is high. Effective rooting depth is limited by a

seasonal high water table that is at a depth of 24 to 48

inches from November to May. Runoff is very slow, and

the hazard of water erosion is slight. This soil is partially

protected from flooding; however, rare periods of flooding

occur from November to April.

This unit is used mainly as cropland and for homesite

development. A few areas are used as woodland.

This unit, where drained and protected from flooding, is

suited to use as cropland. It is limited mainly by the seasonal

high water table. Proper row arrangement, field ditches, and

vegetated outlets are needed to remove excess surface

water. The seasonal high water table generally limits the

suitability of the unit for deep-rooted crops. Tile drainage

can be used to lower the water table if a suitable outlet is

available.

In summer supplemental irrigation is required for maximum

production of most crops. Because of the slow

permeability of the soil, the length of runs should be adjusted

to permit adequate infiltration of water.

A suitable cropping system is one that includes 2 or 3

years of peas or sweet corn and 2 to 4 years of forage crops

used as green chop. An annual crop of vegetables and a

winter cover crop to be used as green manure is also

suitable. Returning all crop residue to the soil and using a

cropping system that includes grasses, legumes, or grasslegume mixtures help to maintain fertility and tilth.

Crop residue left on or near the surface helps to conserve

moisture, maintain tilth, and control erosion. Returning crop

residue to the soil and using minimum tillage help to reduce

compaction. Grain and grasses

respond to nitrogen; legumes respond to phosphorus,

boron, sulfur, and lime; and vegetables and berries

respond to nitrogen, phosphorus, and potassium.

This unit is suited to use as woodland. On the basis of a

50-year site curve, the estimated mean site index for red

alder is 80. The estimated mean annual increment at

culmination (CMAI) for red alder at 40 years of age is about

84 cubic feet per acre.

The main limitation for the harvesting of timber is

wetness. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they are impassable during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is not readily

available on this unit.

Seedling establishment is the main concern for the

production of timber. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily.

Reforestation can be accomplished by planting Douglas-fir

seedlings. When openings are made in the canopy,

invading brushy plants, if not controlled, can delay

establishment of seedlings.

The main limitation for homesites are the hazard of

flooding, wetness, and low soil strength. Dikes and

channels that have outlets to bypass floodwater can be used to

protect buildings from flooding. Buildings and roads

should be designed to offset the limited ability of the soil in this unit

to support a load. Tile drains can be used to lower the water

table around footings.

The main limitations for septic tank absorption fields are

the seasonal high water table and slow permeability. Use of

long absorption lines helps to compensate for the slow

permeability.

This map unit is in capability subclass IIw.

65-Sulsavar gravelly loam, 0 to 8 percent slopes.

This very deep, well drained soil is on terraces and alluvial

fans. It formed in volcanic ash and alluvium. Areas are 10 to

55 acres in size. The native vegetation is mainly conifers.

Elevation is 400 to 1,200 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 46 degrees F, and the average frostfree season is 120 to 180 days.

Typically, the surface is covered with a mat of leaves,

needles, twigs, and mosses about 1 inch thick. The surface

layer is dark brown gravelly loam about 3 inches thick. The

subsoil is stratified dark brown and yellowish brown gravelly

sandy loam, silt loam, and gravelly loam about 30 inches

thick. The substratum to a depth of 60 inches or more is

stratified, dark brown and brown sandy loam, very gravelly

loamy sand, and gravelly sandy loam. In some areas the

surface layer is very gravelly, and in some areas a water

table is at a depth of 25 to 40 inches.

Included in this unit are areas of soils that have slopes of

more than 8 percent; Menzel, Pastik, Skykomish, and

Winston soils on terraces and outwash plains; Elwell
soils on mountainsides and ridgetops; Puyallup soils on stream

terraces; Sultan soils on flood plains; and Tokul soils on till

plains. Included areas make up about 20 percent of the

total acreage.

Permeability of this Sulsavar soil is moderate. Available

water capacity is high. Effective rooting depth is 60 inches

or more. Runoff is slow, and the hazard of water erosion is

slight. The hazard of flooding is rare.

This unit is used mainly as woodland and for hay and

pasture.

Douglas-fir is the main species on this unit. Based on a 100-

year site curve, the mean site index is 183. Based on a 50-

year site curve, the mean site index is 141. The mean annual

increment at culmination (CMAI) for Douglas-fir at age 60 is 194

cubic feet per acre.

Among the trees of limited extent are western hemlock,

western redcedar, and red alder. Among the common forest

understory plants are western swordfern, red huckleberry, vine

maple, ladyfern, and trailing blackberry.

The main limitation for the harvesting of timber is

seasonal soil wetness. Use of wheeled and tracked

equipment when the soil in this unit is wet produces ruts,

compacts the soil, and damages the roots of trees.

Unsurfaced roads and skid trails are soft when wet, and they

may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

Brush competition is the main limitation for timber

production. Reforestation can be accomplished by planting

Douglas-fir. If seed trees are present, natural reforestation of

cutover areas by red alder occurs readily. If openings are

made in the canopy, invading brushy plants, if not controlled,

can prevent reforestation.

This unit is suited to hay and pasture. Use of proper

stocking rates, pasture rotation, and restricted grazing during

wet periods helps to keep the pasture in good condition.

Periodic mowing and spreading of droppings help to maintain

uniform growth and discourage selective grazing. Proper grazing

practices, weed control, and fertilizer are needed for maximum

quality of forage. Legumes benefit from applications of agricultural

lime.

The main limitation for homesites and septic tank

absorption fields is the hazard of flooding. Dikes and

channels that have outlets to bypass floodwater can be

used to protect buildings and onsite sewage disposal

systems from flooding.

This map unit is in capability subclass IVc.

66-Sultan silt loam. This very deep, moderately well

drained soil is on flood plains. It formed in alluvium. Areas

are 10 to 15 acres in size. The native vegetation is mainly

conifers. Elevation is 10 to 120 feet. Slope is 0 to 2 percent.

The average annual precipitation is about 45 inches, the

average annual air temperature is about 49 degrees F, and

the average frost-free season is 150 to 200 days.

Typically, the surface layer is dark grayish brown silt loam

about 12 inches thick. The upper part of the

underlying material is dark grayish brown silty clay loam about 30

inches thick. The lower part to a depth of 60 inches or more

is olive brown, stratified very fine sandy loam and sand. In

some areas the surface layer is silty clay loam or loam or the

soil is somewhat poorly drained.

Included in this unit are small areas of Menzel soils on

terraces, Puget soils in depressional areas on flood plains,

Puyallup soils on stream terraces, and Sultan Variant soils on

flood plains. Included areas make up about 15 percent of

the total acreage. .

Permeability of this Sultan soil is moderately slow.

Available water capacity is high. Effective rooting depth is 60

inches or more. A seasonal high water table is at a depth of

24 to 48 inches from November to April. Runoff is slow, and

the hazard of water erosion is slight. Rare periods of flooding

occurs from November to April.

This unit is used mainly as cropland and for hay and

pasture. It is also used for homesite development. A few

areas are used as woodland.

This unit is suited to use as cropland. Proper row

arrangement, field ditches, and vegetated outlets are

needed to remove excess water on the surface. Tile

drainage can be used to lower the water table if a

suitable outlet is available.

A suitable cropping system is one that includes 2 or 3

years of sweet corn and 4 or 5 years of grasses and

legumes. Growing an annual crop of vegetables and

including an annual winter cover crop to be used as green

manure is also a suitable cropping system.

Returning all crop residue to the soil and using a

cropping system that includes grasses, legumes, or grasslegume mixtures help to maintain fertility and tilth.

Returning crop residue to the soil and practicing minimum

tillage reduce compaction. Grain and grasses respond to

nitrogen; legumes respond to phosphorus, boron, sulfur,

and lime; and vegetables and berries respond to nitrogen,

phosphorus, and potassium.

This unit is suited to hay and pasture. Grazing when the

soil in this unit is wet results in compaction of the surface

layer and poor tilth. Open ditch or tile drains can be used for

drainage. Use of proper stocking rates, pasture rotation, and

restricted grazing during wet periods helps to keep the

pasture in good condition.

Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. Legumes benefit

from applications of agricultural lime.

This unit is suited to use as woodland. On the basis of a

50-year site curve, the estimated mean site index for red

alder is 87. The estimated mean annual increment at

culmination (CMAI) for red alder at 40 years of age is 96

cubic feet per acre.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment to

dry periods. Use of wheeled and tracked equipment when

the soil in this unit is wet produces ruts, compacts the soil,

and damages the roots of trees. Unsurfaced
roads and skid trails are sticky and slippery when wet,

and they may be impassable during rainy periods. Logging

roads require suitable surfacing for year-round use.

If seed trees are present, natural reforestation of

cutover areas by red alder occurs readily. Reforestation can be

accomplished by planting Douglas-fir or western redcedar

seedlings. When openings are made in the canopy,

invading brushy plants, if not controlled, can delay the

establishment of seedlings.

The main limitation for homesites is the hazard of

flooding. Dikes and channels that have outlets to bypass

floodwater can be used to protect buildings from flooding.

Tile drainage around footings reduces wetness. The main

limitations for septic tank absorption fields are the

seasonal high water table and moderately slow

permeability. Use of long absorption lines helps to

compensate for the moderately slow permeability. Cutbanks

are not stable and are subject to caving in.

This map unit is in capability subclass Ilw.

67-Sultan Variant silt loam. This very deep, well drained

soil is on flood plains. It formed in alluvium. Areas are 10 to

40 acres in size. The native vegetation is mainly conifers.

Elevation is 40 to 400 feet. Slope is 0 to 3 percent. The

average annual precipitation is about 55 inches, the average

annual air temperature is about 49 degrees F, and the

average frost-free season is 150 to 200 days.

Typically, the surface layer is very dark grayish brown silt loam

about 9 inches thick. The subsoil is dark grayish brown

and olive brown very fine sandy loam and silt loam about

16 inches thick. Below this is olive brown and olive gray loamy

fine sand, sand, and coarse sand about 25 inches thick over

multicolored very gravelly coarse sand that extends to a

depth of 60 inches or more. Depth to loamy fine sand,

sand, or very gravelly sand ranges from 20 to 32 inches. In

some areas the surface layer is loam or the soil is

moderately well drained.

Included in this unit are small areas of Sultan soils,

Menzel soils on terraces, and Puyallup soils on stream

terraces. Included areas make up about 15 percent of the

total acreage.

Permeability of this Sultan Variant soil is moderate in

the subsoil and rapid below. Available water capacity is

moderate. Effective rooting depth is 60 inches or more.

Runoff is slow, and the hazard of water erosion is slight.

This soil is subject to rare periods of flooding from

November to April.

This unit is used mainly for hay and pasture. It is also

used as cropland and for homesite development. A few

areas are used as woodland.

This unit is suited to hay and pasture. The main

limitation is droughtiness. In some years supplemental

irrigation is needed. Use of proper stocking rates,

pasture rotation, and restricted grazing during wet periods

helps to keep the pasture in good condition.

Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. Legumes

benefit from applications of agricultural lime.

This unit is suited to use as cropland. It is limited mainly by

droughtiness. In summer irrigation is required for maximum

production of most crops. A suitable cropping system is one

that includes 2 or 3 years of peas or sweet corn and 3 to 5

years of grasses and legumes. Growing an annual crop of

vegetables followed by an annual winter cover crop to be

used as green manure is also a suitable cropping system.

Returning all crop residue to the soil and using a cropping

system that includes grasses, legumes, or grass-legume

mixtures help to maintain fertility and tilth. Grain and grasses

respond to nitrogen; legumes respond to phosphorus, boron,

sulfur, and lime; and vegetables respond to nitrogen,

phosphorus, and potassium.

This unit is suited to use as woodland. On the basis of a

50-year site curve, the estimated mean site index for red

alder is 85. The estimated mean annual increment at

culmination (CMAI) for red alder at 40 years of age is about

92 cubic feet per acre.

The main limitation for the harvesting of timber is seasonal

soil wetness, which limits the use of equipment to dry

periods. Use of wheeled and tracked equipment when the soil

in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid trails

are sticky and slippery when wet, and they may be

impassable during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

If seed trees are present, natural reforestation of cutover

areas by red alder occurs readily. Reforestation can be

accomplished by planting Douglas-fir seedlings. When

openings are made in the canopy, invading brushy plants, if

not controlled, can delay establishment of seedlings.

The main limitation for homesites is the hazard of flooding.

Dikes and channels that have outlets to bypass floodwater

can be used to protect onsite sewage disposal systems and

buildings from flooding. The main limitations for septic tank

absorption fields are seepage and the hazard of flooding. If

the density of housing is moderate to high, community

sewage systems are needed to prevent contamination of

water supplies as a result of seepage from onsite sewage

disposal systems. Cutbanks are not stable and are subject to

caving in.

This map unit is in capability subclass Ils.

68-Sumas silt loam. This very deep soil is on flood

plains. The soil is artificially drained. It formed in alluvium.

Areas are 5 to 30 acres in size. The native vegetation is

mainly conifers and hardwoods. Elevation is 10 to 500 feet.

Slope is 0 to 3 percent. The average annual precipitation is

about 45 inches, the average
annual air temperature is about 50 degrees F, and the

average frost-free season is 170 to 210 days.

Typically, the surface is dark grayish brown silt loam

about 14 inches thick. The upper part of the underlying

material is grayish brown and olive gray silt loam and fine

sandy loam about 10 inches thick. The lower part to a depth

of 60 inches or more is pale yellow sand. Depth to sand ranges

from 20 to 32 inches.

Included in this unit are small areas of soils that are

somewhat poorly drained. Also included are areas of Mukilteo

and Puget soils and Terric Medisaprists in depressional

areas; Snohomish, Sultan, and Pilchuck soils on flood

plains; and Puyallup soils on stream terraces. Included areas

make up about 15 percent of the total acreage.

Permeability of this Sumas soil is moderate to the sand

layer and rapid through it. Available water capacity is moderate.

Effective rooting depth is limited by a seasonal high water table

that is at a depth of 24 to 36 inches from November to April.

Runoff is slow, and the hazard of water erosion is slight.

This soil is partially protected from flooding; however, rare

periods of flooding occur from December to March.

This unit is used mainly as cropland and for hay and pasture.

A few areas are used as woodland.

This unit is well suited to use as cropland. In summer

irrigation is required for maximum production of most crops.

A suitable cropping system is one that includes 2 or 3

years of peas or sweet corn and 4 or 5 years of grasses and

legumes. An annual crop of vegetables followed by an annual

winter cover crop to be used as green manure is also suitable.

Returning all crop residue to the soil and using a

cropping system that includes grasses, legumes, or grasslegume mixtures help to maintain fertility and tilth. Returning

crop residue to the soil also reduces crusting of the surface

and compaction. Using minimum tillage helps to reduce

compaction. Grain and grasses respond to nitrogen;

legumes respond to phosphorus, boron, sulfur, and lime;

and vegetables and berries respond to nitrogen,

phosphorus, and potassium.

This unit is well suited to hay and pasture. Grazing when the soil

is wet results in compaction of the surface layer and poor tilth.

Use of proper stocking rates, pasture rotation, and restricted

grazing during wet periods helps to keep the pasture in good

condition.

Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. Legumes benefit

from applications of agricultural lime. In some years

supplemental irrigation is needed.

This unit is suited to use as woodland. On the basis of a 50-year

site curve, the estimated mean site index for red alder is 80.

The estimated mean annual increment at culmination (CMAI)

for red alder at 40 years of age is about 84 cubic feet per

acre.

The main limitation for the harvesting of timber is

seasonal soil wetness. Use of wheeled and tracked

equipment when the soil in this unit is wet produces ruts,

compacts the soil, and damages the roots of trees.

Unsurfaced roads and skid trails are sticky. Logging roads

require suitable surfacing for year-round use. Rock for road

construction is not readily available on this unit.

If seed trees are present, natural reforestation of cutover

areas by red alder occurs readily. Reforestation can be

accomplished by planting western redcedar seedlings. When

openings are made in the canopy, invading brushy plants, if

not controlled, can delay establishment of seedlings.

The main limitations for homesites are the hazard of flooding

and seepage. Cutbanks are not stable and subject to caving in.

Dikes and channels that have outlets to bypass floodwater

can be used to protect buildings from flooding. Wetness can be

reduced by installing drain tile around footings. The main

limitations for septic tank absorption fields are the seasonal

high water table and seepage. If the density of housing is

moderate to high, community sewage systems are needed

to prevent contamination of water supplies as a result of

seepage from onsite sewage disposal systems.

This map unit is in capability subclass IIw.

69-Terric Medisaprists, nearly level. These very deep, very

poorly drained soils are in depressional areas on till plains. They

formed in organic material and alluvium. Areas are 10 to 40

acres in size. The native vegetation is mainly conifers and

hardwoods. Elevation is 25 to 1,200 feet. Slope is 0 to 3

percent. The average annual precipitation is about 55 inches, the

average annual air temperature is about 50 degrees F, and the

average frost-free season is 160 to 180 days.

Typically, the upper layer is black and dark brown organic

material 28 inches thick. The substratum to a depth of 60 inches

or more is dark brown and very dark gray very gravelly loamy

sand. The substratum varies widely in texture, ranging from

clay to loamy sand within short distances.

Included in this unit are small areas of soils that have volcanic ash

in the profile. Also included are areas of Alderwood and Tokul

soils on till plains, Snohomish soils on flood plains, and

Mukilteo and Orcas soils in depressional areas on hills.

Included areas make up about 15 percent of the total acreage.

Permeability of Terric Medisaprists is moderate.

Available water capacity is moderate. Effective rooting

depth is limited by the seasonal high water table that is at a

depth of 24 to 48 inches where drained. Runoff is ponded,

and the hazard of water erosion is slight.

This unit is used mainly for wildlife habitat. Some areas have been

drained and are used for hay and pasture or cropland and for

homesite development.

If this unit is used for cropland, the main limitation is

wetness because of the seasonal high water table.

Proper row arrangement, field ditches, and vegetated

outlets are needed to remove excess water from the

surface. Deep-rooted crops are suited to areas where
the drainage is adequate or where a drainage system has been

installed. Tile drainage can be used to lower the water table

if a suitable outlet is available. Subsidence is minimized if

the water table is maintained immediately below the root zone

and allowed to return to the surface outside the growing

season. In summer irrigation is required for maximum production

of most crops.

A suitable cropping system is one that includes 1 or 2

years of peas or sweet corn and 3 or 4 years of grasses and

legumes. An annual crop of vegetables followed by an

annual winter cover crop to be used as green manure is

also suitable. Returning all crop residue to the soil and

using a cropping system that includes grasses, legumes, or

grass-legume mixtures help to maintain fertility and tilth.

Grasses respond to nitrogen; legumes respond to phosphorus,

boron, sulfur, and lime; and vegetables and berries respond

to nitrogen, phosphorus, and potassium.

If this unit is used for hay and pasture, the main

limitation is wetness because of the seasonal high water

table. Grazing when the soil is wet results in compaction of

the surface layer, poor tilth, and excessive runoff.

Excessive water can be removed by open ditch or tile

drainage if adequate outlets are available. Use of proper stocking

rates, pasture rotation, and restricted grazing during wet

periods helps to keep the pasture in good condition.

Periodic mowing and spreading of droppings help to maintain

uniform growth and discourage selective grazing. Proper grazing

practices, weed control, and fertilizer are needed for maximum

quality of forage. Legumes benefit from applications of

agricultural lime. In some years supplemental irrigation is

needed.

The main limitation for homesites and septic tank

absorption fields is wetness. Where outlets are available, excess

water can be removed by using shallow ditches. Wetness

can be reduced by installing drain tile around footings. Septic

tank absorption fields often fail or do not function properly

during the rainy season.

This map unit is in capability subclass Ilw.

70-Tokul silt loam, 2 to 8 percent slopes. This

moderately deep, moderately well drained soil is on till

plains. It formed in glacial till and volcanic ash. Areas are

10 to 40 acres in size. The native vegetation is mainly

conifers. Elevation is 200 to 800 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 46 degrees F, and the average frostfree season is 140 to 200 days.

Typically, the surface is covered with a mat of leaves,

twigs, and decomposed litter about 2 inches thick. The

surface layer is dark brown silt loam about 12 inches thick.

The subsoil is brown, strong brown, and dark yellowish

brown gravelly loam about 10 inches thick. The substratum

is light olive brown gravelly fine sandy loam about 9 inches

thick. A hardpan is at a depth of about 31 inches. Depth to

the hardpan ranges from 20 to 40 inches. In some areas the

surface layer is gravelly loam

or the soil does not have a hardpan but is underlain by

compact glacial till at a depth of 20 to 40 inches.

Included in this unit are small areas of Pastik soils on

terraces. Included areas make up about 25 percent of the

total acreage.

Permeability of this Tokul soil is moderate to the hardpan

and very slow through it. Available water capacity is

moderate. Effective rooting depth is limited by a seasonal

perched water table that is at a depth of 18 to 36 inches

from November to May. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used mainly as woodland and for hay and

pasture. It is also used for homesite development.

Douglas-fir and western hemlock are the main woodland

species on this unit. On the basis of a 100-year site curve,

the mean site index is 173 for Douglas-fir and 166 for

western hemlock. On the basis of a 50-year site curve, the

mean site index is 131 for Douglas-fir and 117 for western

hemlock. The mean annual increment at culmination (CMAI)

is 184 cubic feet per acre for Douglas-fir at age 60 and 266

cubic feet per acre for western hemlock at age 50. Among

the trees of limited extent are western redcedar, red alder,

and bigleaf maple. Among the common forest understory

plants are western swordfern, brackenfern, red huckleberry,

salal, and trailing huckleberry.

The main limitation for the harvesting of timber is seasonal

soil wetness, which limits the use of equipment to dry

periods. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid trails

are soft when wet, and they may be impassable during rainy

periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is not readily available

on this unit.

Reforestation can be accomplished by planting Douglas-fir

seedlings. If seed trees are present, natural reforestation of

cutover areas by Douglas-fir and red alder occurs readily and

natural reforestation by western hemlock occurs periodically.

When openings are made in the canopy, invading brushy

plants, if not controlled, can prevent reforestation.

Because the rooting depth is restricted by the hardpan,

trees are occasionally subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly

subject to windthrow than are more deeply rooted trees.

This unit is suited to hay and pasture. The main limitations

are wetness and depth to the hardpan, which reduces the

yield of deep-rooted plants. Excess water can be removed

by open ditches or tile drains if a suitable outlet is available.

Use of proper stocking rates, pasture rotation, and restricted

grazing during wet periods helps to keep the pasture in

good condition and to protect the soil from erosion.

Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing.

Proper grazing practices, weed control, and
fertilizer are needed for maximum quality of forage. Legumes

benefit from applications of agricultural lime. In some years

supplemental irrigation is needed. Subsoiling may be effective

in breaking through the hardpan.

The main limitation for homesites is the seasonal high

water table. Wetness can be reduced by installing drain tile

around footings. The main limitations for septic tank

absorption fields are the depth to the hardpan and wetness.

Onsite sewage disposal systems often fail or do not function

properly during periods of high rainfall.

This map unit is in capability subclass Ille.

71-Tokul silt loam, 8 to 15 percent slopes. This

moderately deep, moderately well drained soil is on till

plains. It formed in glacial till and volcanic ash. Areas are 10

to 40 acres in size. The native vegetation is mainly

conifers. Elevation is 200 to 800 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 46 degrees F, and the average frostfree season is 140 to 200 days.

Typically, the surface is covered with a mat of leaves,

twigs, and decomposed litter about 2 inches thick. The

surface layer is dark brown silt loam about 12 inches thick.

The subsoil is brown, strong brown, and dark yellowish brown

gravelly loam about 10 inches thick. The substratum is

light olive brown gravelly fine sandy loam about 9 inches

thick. A hardpan is at a depth of about 31 inches. Depth to

the hardpan ranges from 20 to 40 inches. In some areas the

surface layer is gravelly loam or the soil does not have a

hardpan but is underlain by glacial till at a depth of 20 to 40

inches.

Included in this unit are areas of Pastik soils on

terraces. Included areas make up about 25 percent of the total

acreage.

Permeability of this Tokul soil is moderate. Effective

rooting depth is limited by a seasonal perched water table

that is at a depth of 18 to 36 inches from November to

May. Runoff is medium, and hazard of water erosion is

moderate.

This unit is used mainly as woodland and for hay and

pasture. It is also used for homesite development.

Douglas-fir and western hemlock are the main woodland

species on this unit. On the basis of a 100-year site curve,

the mean site index is 173 for Douglas-fir and 166 for

western hemlock. On the basis of a 50-year site curve, the

mean site index is 131 for Douglas-fir and 117 for western

hemlock. The mean annual increment at culmination

(CMAI) is 184 cubic feet for Douglas-fir at age 60 and 266

cubic feet per acre for western hemlock at age 50.

Among the trees of limited extent are western redcedar,

red alder, and bigleaf maple. Among the common forest

understory plants are western swordfern, brackenfern, red

huckleberry, salal, and trailing blackberry.

The main limitation for the harvesting of timber is

seasonal soil wetness, which restricts the use of

equipment to dry periods. Use of wheeled and tracked

equipment when the soil in this unit is wet produces ruts,

compacts the soil, and damages the roots of trees.

Unsurfaced roads and skid trails are soft when wet, and they

may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for

road construction is not readily available on this unit.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily

and natural reforestation by western hemlock occurs

periodically. When openings are made in the canopy,

invading brushy plants, if not controlled, can prevent

reforestation.

Because the rooting depth is restricted by the hardpan,

trees are occasionally subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly

subject to windthrow than are more deeply rooted trees.

This unit is suited to hay and pasture. The main limitations

are wetness and the hardpan, which reduces the yield of

deep-rooted plants. Use of proper stocking rates, pasture

rotation, and restricted grazing during wet periods helps to

keep the pasture in good condition and to protect the soil

from erosion.

Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. Legumes benefit

from applications of agricultural lime. In some years

supplemental irrigation is needed. Subsoiling may be effective in

breaking through the hardpan.

The main limitation for homesites is the seasonal high

water table. Wetness can be reduced by installing drain tile

around footings. The main limitations for septic tank

absorption fields are the depth to the hardpan and

wetness. Onsite sewage disposal systems often fail or do

not function properly during the periods of high rainfall

because of the restrictive layer.

This map unit is in capability subclass Ille.

72-Tokul gravelly loam, 0 to 8 percent slopes. This

moderately deep, moderately well drained soil is on till

plains. It formed in glacial till and volcanic ash. Areas are

long and narrow and are oriented from northwest to

southeast. They are 40 to 100 acres in size. The native

vegetation is mainly conifers. Elevation is 200 to 800 feet.

The average annual precipitation is about 55 inches, the

average annual air temperature is about 46 degrees F, and

the average frost-free season is 140 to 200 days.

Typically, the surface is covered with a mat of leaves,

twigs, and decomposed litter about 2 inches thick. The

surface layer is dark brown gravelly loam about 4 inches

thick. The subsoil is brown, strong brown, and dark yellowish

brown gravelly loam about 18 inches thick. The substratum

is light olive brown gravelly fine sandy loam
about 9 inches thick. A hardpan is at a depth of about 31

inches. Depth to the hardpan ranges from 20 to 40 inches.

In some areas the surface layer is cobbly loam or the soil does

not have a hardpan but is underlain by compact glacial till

at a depth of 20 to 40 inches.

Included in this unit are areas of soils that have slopes of

more than 8 percent, McKenna and Norma soils in

depressional areas along drainageways on till plains, Terric

Medisaprists in depressional areas on till plains, Winston and

Pastik soils on terraces and outwash plains, and Ragnar soils on

outwash plains. Included areas make up about 25 percent of

the total acreage.

Permeability of this Tokul soil is moderate above the hardpan

and very slow through it. Available water capacity is moderate.

Effective rooting depth is limited by a seasonal perched

water table that is at a depth of 18 to 36 inches from

November to May. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used mainly as woodland. It is also used for urban

development and for hay and pasture.

Douglas-fir and western hemlock are the main woodland

species on this unit. On the basis of a 100-year site curve,

the mean site index is 173 for Douglas-fir and 166 for western

hemlock. On the basis of a 50-year site curve, the mean site

index is 131 for Douglas-fir and 117 for western hemlock. The

mean annual increment at culmination (CMAI) is 184 cubic feet

per acre for Douglas-fir at age 60 and 266 cubic feet per

acre for western hemlock at age 50.

Among the trees of limited extent are western redcedar, red

alder, and bigleaf maple. Among the common forest understory

plants are western swordfern, brackenfern, red huckleberry,

salal, and trailing blackberry.

The main limitation for the harvesting of timber is seasonal

soil wetness, which limits the use of equipment to dry periods.

Use of wheeled and tracked equipment when the soil in

this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is not readily

available on this unit.

Brush competition is the main limitation in the production of

timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily

and natural reforestation by western hemlock occurs periodically.

When openings are made in the canopy, invading brushy

plants, if not controlled, can prevent reforestation.

Because the rooting depth is restricted by the hardpan,

trees are occasionally subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly

subject to windthrow than are more deeply rooted

trees.

The main limitations for hay and pasture are wetness

and the depth to the hardpan, which reduces the yield of

deep-rooted plants. Excess water can be removed by open

ditches or tile drains. Use of proper stocking rates, pasture

rotation, and restricted grazing during wet periods helps to

keep the pasture in good condition.

Periodic mowing and spreading of droppings help to

maintain uniform growth and discourage selective grazing.

Proper grazing practices, weed control, and fertilizer are

needed for maximum quality of forage. Legumes benefit

from applications of agricultural lime. In some years

supplemental irrigation is needed. Small stones may

interfere with tillage operations. Subsoiling may be effective

in breaking through the hardpan.

The main limitation for homesites is wetness, which can

be reduced by installing drain tile around footings.

The main limitations for septic tank absorption fields

are the depth to the hardpan and wetness. Onsite sewage

disposal systems often fail or do not function properly

during periods of high rainfall.

This map unit is in capability subclass Ille.

73-Tokul gravelly loam, 8 to 15 percent slopes. This

moderately deep, moderately well drained soil is on till

plains. It formed in glacial till and volcanic ash. Areas are

oriented from northwest to southeast and are 40 to 100

acres in size. The native vegetation is mainly conifers.

Elevation is 200 to 800 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 46 degrees F, and the average frostfree season is 140 to 200 days.

Typically, the surface is covered with a mat of leaves,

twigs, and decomposed litter about 2 inches thick. The

surface layer is dark brown gravelly loam about 4 inches

thick. The subsoil is brown, strong brown, and dark yellowish

brown gravelly loam about 18 inches thick. The substratum

is light olive brown gravelly fine sandy loam about 9 inches

thick. A hardpan is at a depth of about 31 inches. Depth to

the hardpan ranges from 20 to 40 inches. In some areas the

surface layer is cobbly or the soil does not have a hardpan

but is underlain by compact glacial till at a depth of 20 to 40

inches.

Included in this unit are small areas of Pastik and

Winston soils on terraces and outwash plains; Nargar soils on

high terraces, terrace escarpments, and outwash plains;

and Ragnar soils on outwash plains. Included areas

make up about 25 percent of the total acreage.

Permeability of this Tokul soil is moderate to the hardpan

and very slow through it. Available water capacity is

moderate. Effective rooting depth is limited by a seasonal

perched water table that is at a depth of 18 to 36 inches

from November to May. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used mainly as woodland. It is also used for

homesite development and for hay and pasture.

Douglas-fir and western hemlock are the main woodland

species on this unit. On the basis of a 100-year site curve,

the mean site index is 173 for Douglas-fir and 166 for

western hemlock. On the basis of a 50-year
site curve, the mean site index is 131 for Douglas-fir and

117 for western hemlock. The mean annual increment at

culmination (CMAI) is 184 cubic feet per acre for Douglas-fir

at age 60 and 266 cubic feet per acre for western hemlock

at age 50.

Among the trees of limited extent are western redcedar,

red alder, and bigleaf maple. Among the common forest

understory plants are western swordfern, brackenfern, red

huckleberry, salal, and trailing blackberry.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment to dry

periods. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid

trails are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is not readily

available on this unit.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily and

natural reforestation by western hemlock occurs periodically.

When openings are made in the canopy, invading brushy

plants, if not controlled, can prevent reforestation.

Because the rooting depth is restricted by the hardpan,

trees are occasionally subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly

subject to windthrow than are more deeply rooted

trees.

This unit is suited to hay and pasture. The main limitations

are wetness because of the seasonal perched water

table and depth to the hardpan, which reduces the yield of

deep-rooted plants. Excess water can be removed by

open ditches or tile drains. Use of proper stocking rates,

pasture rotation, and restricted grazing during wet periods

helps to keep the pasture in good condition and to protect

the soil from erosion.

Periodic mowing and spreading of droppings help to maintain

uniform growth and discourage selective grazing. Proper

grazing practices, weed control, and fertilizer are needed for

maximum quality of forage. Legumes benefit from

applications of agricultural lime. In some years

supplemental irrigation is needed. Small stones may

interfere with tillage. Subsoiling may be effective in breaking

through the hardpan.

The main limitation for homesites is the seasonal

perched water table. Wetness can be reduced by

installing drain tile around footings.

The main limitations for septic tank absorption fields are

the depth to the hardpan and wetness. Onsite sewage

disposal systems often fail or do not function properly

during periods of high rainfall.

This map unit is in capability subclass Ille.

74-Tokul gravelly loam, 15 to 25 percent slopes. This

moderately deep, moderately well drained soil is on

till plains. If formed in glacial till and volcanic ash. Areas are

oriented from northwest to southeast and are 40 to 100

acres in size. The native vegetation is mainly conifers.

Elevation is 200 to 800 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 46 degrees F, and the average frostfree season is 140 to 200 days.

Typically, the surface is covered with a mat of leaves,

twigs, and decomposed litter about 2 inches thick. The

surface layer is dark brown gravelly loam about 4 inches

thick. The subsoil is brown, strong brown, and dark yellowish

brown gravelly loam about 18 inches thick. The substratum

is light olive brown gravelly fine sandy loam about 9 inches

thick. A hardpan is at a depth of about 31 inches. Depth to

the hardpan ranges from 20 to 40 inches. In some areas the

surface layer is cobbly or the soil does not have a hardpan

but is underlain by compact glacial till at a depth of 20 to 40

inches.

Included in this unit are areas of McKenna and Norma

soils in depressional areas along drainageways on till plains,

Terric Medisaprists in depressional areas on till plains,

Winston and Pastik soils on terraces and outwash plains,

and Ragnar soils on outwash plains. Included areas make up

about 25 percent of the total acreage.

Permeability of this Tokul soil is moderate to the hardpan

and very slow through it. Available water capacity is

moderate. Effective rooting depth is limited by a seasonal

perched water table that is at a depth of 18 to 36 inches

from November to May. Runoff is medium, and the hazard of

water erosion is moderate.

This unit is used mainly as woodland. It is also used for

homesite development.

Douglas-fir and western hemlock are the main woodland

species on this unit. On the basis of a 100-year site curve,

the mean site index is 173 for Douglas-fir and 166 for

western hemlock. On the basis of a 50-year site curve, the

mean site index is 131 for Douglas-fir and 117 for western

hemlock. The mean annual increment at culmination (CMAI)

is 184 cubic feet per acre for Douglas-fir at age 60 and 266

cubic feet per acre for western hemlock at age 50.

Among the trees of limited extent are western

redcedar, red alder, and bigleaf maple. The common

forest understory plants are western swordfern,

brackenfern, red huckleberry, salal, and trailing

blackberry.

The main limitation for the harvesting of timber is

seasonal soil wetness, which limits the use of equipment to

dry periods. Use of wheeled and tracked equipment when the

soil in this unit is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid trails

are soft when wet, and they may be impassable during rainy

periods. Logging roads require suitable surfacing for yearround use. Rock for road construction is not readily available

on this unit. Establishing plant cover on steep road cut and

fill slopes reduces erosion. Disturbance of the protective

layer of duff can be reduced with the careful use of wheeled

and tracked equipment.
Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily

and that of western hemlock occurs periodically. When

openings are made in the canopy, invading brushy

plants, if not controlled, can prevent reforestation.

Because the rooting depth is restricted by the

hardpan, trees are occasionally subject to windthrow.

Western hemlock, a shallow-rooted tree, is more

commonly subject to windthrow than are more deeply

rooted trees.

The main limitation for homesites is the seasonal high

water table. Wetness can be reduced by installing drain tile

around footings. The main limitations for septic tank

absorption fields are steepness of slope, wetness, and

depth to the hardpan. Onsite sewage disposal systems often fail

or do not function properly during periods of high rainfall

because of the pan. Access roads must be designed to

control surface runoff and help stabilize cut slopes.

This map unit is in capability subclass IVe.

75-Tokul-Ogarty-Rock outcrop complex, 0 to 25

percent slopes. This map unit is on till plains and foothills.

Areas are irregular in shape and 25 to 80 acres in size. The

native vegetation is mainly conifers. Elevation is 350 to 1,000

feet. The average annual precipitation is about 60 inches, the

average annual air temperature is about 46 degrees F, and

the average frost-free season is 140 to 180 days.

This unit is about 60 percent Tokul silt loam, about 20

percent Ogarty very gravelly loam, and about 10 percent Rock

outcrop. The components of this unit are so intricately

intermingled that it was not practical to map them

separately at the scale used.

Included in this unit are small areas of Nargar, Pastik, and

Winston soils on terraces and outwash plains, Ragnar soils on

outwash plains, and Terric Medisaprists in depressional areas

on till plains. Also included are some areas of soils that do

not have a hardpan but are underlain by compact glacial till

at a depth of 20 to 40 inches. Included areas make up

about 10 percent of the total acreage.

The Tokul soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface is covered with a mat of leaves, twigs, and

decomposed litter about 2 inches thick. The surface layer

is dark brown gravelly loam about 4 inches thick. The

subsoil is brown, strong brown, and dark yellowish brown

gravelly loam about 18 inches thick. The substratum is

light olive brown gravelly fine sandy loam about 9 inches

thick. A hardpan is at a depth of about 31 inches. Depth to

the hardpan ranges from 20 to 40 inches.

Permeability of the Tokul soil is moderate to the

hardpan and very slow through it. Available water

capacity is moderate. Effective rooting depth is limited by a

seasonal perched water table that is at a depth of 18 to 36

inches from November to May. Runoff is medium, and the

hazard of water erosion is moderate.

The Ogarty soil is moderately deep and moderately well

drained. It formed in volcanic ash and glacial till derived

dominantly from andesite. Typically, the surface is covered with

a mat of litter and decomposed material about 2 inches

thick. The surface layer, where mixed to a depth of about 6

inches, is dark brown very gravelly loam. The subsoil is

dark brown very gravelly loam and brown extremely

gravelly loam about 26 inches thick. The substratum is dark

brown and yellowish red extremely gravelly loam about 6

inches thick. Andesite is at a depth of about 38 inches.

Depth to andesite ranges from 20 to 40 inches.

Permeability of the Ogarty soil is moderate. Available

water capacity is low. Effective rooting depth is 20 to 40

inches. Runoff is medium, and the hazard of water erosion is

moderate.

Rock outcrop consists of areas where 90 percent of the

surface is exposed andesite or argillite. It occurs as very

steep cliffs.

This unit is used mainly as woodland.

Douglas-fir and western hemlock are the main woodland

species on the Tokul soil. On the basis of a 100-year site

curve, the mean site index is 173 for Douglas-fir and 166 for

western hemlock. On the basis of a 50-year site curve, the

mean site index is 131 for Douglas-fir and 117 for western

hemlock. The mean annual increment at culmination (CMAI)

is 184 cubic feet per acre for Douglas-fir at age 60 and 266

cubic feet per acre for western hemlock at age 50.

Douglas-fir and western hemlock are also the main

woodland species on the Ogarty soil. On the basis of a 100-

year site curve, the mean site index is 150 for Douglas-fir

and 176 for western hemlock. On the basis of a 50-year site

curve, the mean site index is 117 for Douglas-fir and 115 for

western hemlock. The mean annual increment at

culmination (CMAI) is 158 cubic feet per acre for Douglasfir at age 60 and 285 cubic feet per acre for western

hemlock at age 50. The areas of Rock outcrop in this unit

reduce yield by about 10 percent.

Among the trees of limited extent on this unit are western

redcedar, red alder, Pacific silver fir, and bigleaf maple.

Among the common forest understory plants are western

swordfern, brackenfern, red huckleberry, salal, and trailing

blackberry.

The main limitation for the harvesting of timber is seasonal

soil wetness, which limits the use of equipment on the Tokul

soil. The areas of Rock outcrop hinder

yarding operations. Use of wheeled and tracked equipment

when the soil is wet produces ruts, compacts the soil, and

damages the roots of trees. Unsurfaced roads and skid trails

are soft when wet, and they may be impassable during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is readily

available on this unit. Establishing
plant cover on steep road cut and fill slopes reduces

erosion. Disturbance of the protective layer of duff

can be reduced with the careful use of wheeled and

tracked equipment.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily

and that of western hemlock occurs periodically. When

openings are made in the canopy, invading brushy plants,

if not controlled, can prevent reforestation. Rock outcrop

limits the even distribution of reforestation.

Because the rooting depth is restricted by the hardpan

and underlying bedrock, trees are subject to windthrow.

Western hemlock, a shallow-rooted tree, is more commonly

subject to windthrow than are more deeply rooted trees.

The main limitation for septic tank absorption fields and

homesites is the steepness of slope in areas where slopes

are more than 15 percent. Rock outcrop may interfere

with the placement of septic tank absorption lines. On the

Tokul soil a seasonal high water table is perched above the

hardpan; thus, drainage is needed if buildings with basements

and crawl spaces are constructed. On the Ogarty soil deep

cuts can expose bedrock.

This map unit is in capability subclass Vle.

76-Tokul-Ogarty-Rock outcrop complex, 25 to 65

percent slopes. This map unit is on till plains and foothills.

Areas are irregular in shape and are 40 to 100 acres in

size. The native vegetation is mainly conifers. Elevation is

500 to 1,000 feet. The average annual precipitation is about

60 inches, the average annual air temperature is about 46

degrees F, and the average frost-free season is 140 to

180 days.

This unit is about 50 percent Tokul gravelly loam,

about 25 percent Ogarty very gravelly loam, and about 10

percent Rock outcrop. The components of this unit are so

intricately intermingled that it was not practical to map

them separately at the scale used. In some areas the

soil does not have a hardpan but is underlain by compact

glacial till at a depth of 20 to 40 inches.

Included in this unit are small areas of Elwell and

Olomount soils on mountainsides and ridgetops, Pastik and

Winston soils on terraces and outwash plains, and talus

slopes below areas of Rock outcrop. Included areas make

up about 15 percent of the total acreage.

The Tokul soil is moderately deep and moderately

well drained. It formed in glacial till and volcanic ash.

Typically, the surface is covered with a mat of leaves, twigs,

and decomposed litter about 2 inches thick. The surface

layer is dark brown gravelly loam about 4 inches thick.

The subsoil is brown, strong brown, and dark yellowish

brown gravelly loam about 18 inches thick. The substratum

is light olive brown gravelly fine sandy loam about 9

inches thick. A hardpan is at a depth of about

31 inches. Depth to the hardpan ranges from 20 to 40

inches.

Permeability of the Tokul soil is moderate to the hardpan

and very slow through it. Available water capacity is

moderate. Effective rooting depth is limited by a seasonal

perched water table that is at a depth of 18 to 36 inches

from November to May. Runoff is rapid, and the hazard of

water erosion is high.

The Ogarty soil is moderately deep and moderately well

drained. It formed in volcanic ash and glacial till derived

dominantly from andesite. Typically, the surface is

covered with a mat of litter and decomposed material about

2 inches thick. The surface layer, where mixed to a depth of

about 6 inches, is dark brown very gravelly loam. The

subsoil is dark brown very gravelly loam and brown

extremely gravelly loam about 26 inches thick. The

substratum is dark brown and yellowish red extremely

gravelly loam about 6 inches thick. Andesite is at a depth of

about 38 inches. Depth to andesite ranges from 20 to 40

inches.

Permeability of the Ogarty soil is moderate. Available

water capacity is low. Effective rooting depth is 20 to 40

inches. Runoff is rapid, and the hazard of water erosion is

high.

Rock outcrop consists of areas where 90 percent of the

surface is exposed andesite or argillite. It occurs as steep

cliffs.

This unit is used mainly as woodland.

Douglas-fir and western hemlock are the main woodland

species on the Tokul soil. On the basis of a 100-year site

curve, the mean site index is 173 for Douglas-fir and 166 for

western hemlock. On the basis of a 50-year site curve, the

mean site index is 131 for Douglas-fir and 117 for western

hemlock. The mean annual increment at culmination (CMAI) is

184 cubic feet per acre for Douglas-fir at age 60 and 266

cubic feet per acre for western hemlock at age 50.

Douglas-fir and western hemlock are also the main

woodland species on the Ogarty soil. On the basis of a 100-

year site curve, the mean site index is 150 for Douglas-fir

and 176 for western hemlock. On the basis of a 50-year site

curve, the mean site index is 117 for Douglas-fir and 115 for

western hemlock. The mean annual increment at culmination

(CMAI) is 158 cubic feet per acre for Douglas-fir at age 60

and 285 cubic feet per acre for western hemlock at age 50.

Rock outcrop in this unit reduces yield by about 10

percent.

Among the trees of limited extent in this unit are western

redcedar, red alder, bigleaf maple, and Pacific silver fir.

Among the common forest understory plants

are western swordfern, brackenfern, red huckleberry,

salal, and trailing blackberry.

The main limitation for the harvesting of timber is the

steepness of slope, which restricts the use of wheeled

and tracked equipment in skidding operations. Use of cable

yarding systems on the steeper parts of this unit generally

is safer and disturbs the soil less. Rock
outcrop may hinder yarding operations. Unsurfaced roads

and skid trails are soft when wet, and they may be

impassable during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is readily available on this unit.

The seasonal perched water table of the Tokul soil

limits the use of equipment. Steep yarding paths, skid

trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or they are

protected by plant cover. Establishing plant cover on steep

road cut and fill slopes reduces erosion.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily and

that of western hemlock occurs periodically. When openings

are made in the canopy, invading brushy plants, if not

controlled, can prevent the establishment of conifer seedlings.

Rock outcrop limits the even distribution of reforestation.

Because the rooting depth is restricted by the hardpan and

underlying bedrock, trees are occasionally subject to windthrow.

Western hemlock, a shallow-rooted tree, is more commonly

subject to windthrow than are more deeply rooted trees.

This map unit is in capability subclass VIIe.

77-Tokul-Winston gravelly loam, 25 to 65 percent slopes.

This map unit is on till plains and terrace escarpments. Areas

are irregular in shape and are 20 to 160 acres in size. The native

vegetation is mainly conifers. Elevation is 200 to 900 feet. The

average annual precipitation is about 55 inches, the average

annual air temperature is about 46 degrees F, and the

average frost-free season is 140 to 200 days.

This unit is about 50 percent Tokul gravelly loam and

about 30 percent Winston gravelly loam. The components

of this unit are so intricately intermingled that it was not

practical to map them separately at the scale used.

Included in this unit are soils that are similar to the Tokul

soil but do not have a hardpan; however, they are underlain by

compact glacial till at a depth of 20 to 40 inches. Also

included are small areas of Pastik soils on terraces and

Ragnar soils on outwash plains. Included areas make up about

20 percent of the total acreage.

The Tokul soil is moderately deep and moderately well

drained. It formed in glacial till and volcanic ash. Typically,

the surface is covered with a mat of leaves, twigs, and

decomposed litter about 2 inches thick. The surface layer is

dark brown gravelly loam about 4 inches thick. The subsoil

is brown, strong brown, and dark yellowish brown gravelly

loam about 18 inches thick. The substratum is light olive brown

gravelly fine sandy loam about 9 inches thick. A hardpan is at

a depth of about 31 inches. Depth to the hardpan ranges from

20 to 40 inches.

Permeability of the Tokul soil is moderate to the

hardpan and very slow through it. Available water

capacity is moderate. Effective rooting depth is limited by a

seasonal perched water table that is at a depth of 18 to 36 inches

from November to May. Runoff is rapid, and the hazard of

water erosion is high.

The Winston soil is very deep and somewhat excessively

drained. It formed in glacial outwash and volcanic ash.

Typically, the surface is covered with a mat of needles,

leaves, twigs, and decomposed litter about 2 inches thick. The

surface layer is dark brown gravelly loam about 3 inches thick. The

subsoil is dark brown, strong brown, and yellowish brown

gravelly loam and gravelly fine sandy loam about 13 inches

thick. The upper part of the substratum is yellowish brown

gravelly fine sandy loam about 9 inches thick. The lower part

to a depth of 60 inches or more is very dark grayish brown

extremely gravelly coarse sand.

Permeability of the Winston soil is moderate to the lower part

of the substratum and very rapid through it. Available water

capacity is low. Effective rooting depth is 60 inches or more. Runoff

is rapid, and the hazard of water erosion is high.

This unit is used mainly as woodland.

Douglas-fir and western hemlock are the main woodland

species on the Tokul soil. On the basis of a 100-year site curve,

the mean site index is 173 for Douglas-fir and 166 for western

hemlock. On the basis of a 50-year site curve, the mean site index

is 131 for Douglas-fir and 117 for western hemlock. The mean

annual increment at culmination (CMAI) is 184 cubic feet per acre

for Douglas-fir at age 60 and 266 cubic feet per acre for western

hemlock at age 60.

Douglas-fir and western hemlock are also the main

woodland species on the Winston soil. On the basis of a 100-year

site curve, the mean site index is 167 for Douglas-fir and 164 for

western hemlock. On the basis of a 50-year site curve, the mean

site index is 127 for Douglas-fir and 104 for western hemlock.

The mean annual increment at culmination (CMAI) is 178

cubic feet per acre for Douglas-fir at age 60 and 262 cubic feet per

acre for western hemlock at age 60.

Among the trees of limited extent on this unit are western

redcedar, red alder, and bigleaf maple. Among the common

forest understory plants are western swordfern,

brackenfern, red huckleberry, salal, and trailing blackberry.

The main limitations for the harvesting of timber are

seasonal soil wetness and steepness of slope. The seasonal

perched water table in the Tokul soil limits the use of equipment

to dry periods. When harvesting timber, steep slopes restrict

the use of wheeled and tracked equipment in skidding operations.

Use of cable yarding systems on the steeper. parts of this unit

generally is safer and disturbs the soil less. Unsurfaced

roads and skid trails are soft when wet, and they may be

impassable during rainy periods. Logging roads require suitable

surfacing for year-round use. Rock for road construction is

readily available on this unit.

 Steep yarding paths, skid trails, and firebreaks are subject to

rilling and gullying unless adequate water bars
are provided or they are protected by plant cover.

Establishing plant cover on steep road cut and fill slopes

reduces erosion.

Brush competition is the main limitation for the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily

and that of western hemlock occurs periodically. When

openings are made in the canopy, invading brushy

plants, if not controlled, can prevent reforestation.

Because the rooting depth is restricted by the hardpan in

the Tokul soil, trees are subject to windthrow. Western

hemlock, a shallow-rooted tree, is more commonly subject to

windthrow than are more deeply rooted trees.

This map unit is in capability subclass VIle.

78-Urban land. This map unit consists of nearly level to

gently sloping areas covered by streets, buildings, parking lots,

and other structures that obscure or alter the soils so that

identification is not feasible. Areas are 10 to 50 acres in

size. Elevation is 50 to 450 feet. The average annual

precipitation is about 40 inches. The mean annual air

temperature is about 52 degrees F, and the average frost-free

season is about 200 days.

Included in this unit are small areas of Alderwood,

Everett, and Tokul soils.

This map unit is not assigned a capability

classification.

79-Verlot mucky silt loam, 3 to 25 percent slopes.

This moderately deep, moderately well drained soil is on

mountainsides and ridgetops. It formed in glacial till and

volcanic ash. Areas are 30 to 100 acres in size. The native

vegetation is mainly conifers. Elevation is 2,800 to 4,000

feet. The average annual precipitation is about 90 inches,

the average annual air temperature is about 41 degrees

F, and the average frost-free season is 90 to 100 days.

Typically, the surface is covered with a mat of partially

decomposed leaves, twigs, and needles about 2 inches

thick. The surface layer is black mucky silt loam about 10

inches thick. The subsurface layer is brown silt loam about 6

inches thick. The subsoil is reddish brown and dark brown

silt loam and gravelly loam about 19 inches thick. Olive

brown, dense glacial till is at a depth of about 35 inches.

Depth to glacial till ranges from 20 to 40 inches.

Included in this unit are small areas of Cryohemists,

nearly level, in depressional areas on high mountain ridgetops.

Also included are small areas of Getchell, Hartnit, Oso,

and Potchub soils on mountainsides and ridgetops.

Included areas make up about 15 percent of the total

acreage.

Permeability of this Verlot soil is moderate to the glacial

till and very slow through it. Available water capacity is

moderate. Effective rooting depth is limited by a seasonal

perched water table that is at a depth of 12

to 36 inches from November to May. Runoff is slow, and the

hazard of water erosion is slight. The effect of the layer of

dense glacial till on use and management is similar to that of

a hardpan.

This unit is used mainly as woodland and watershed.

Western hemlock and Pacific silver fir are the main

woodland species on this unit. On the basis of a 100year

site curve, the mean site index for western hemlock is 85.

On the basis of a 50-year site curve, the mean site index is

60. The estimated mean annual increment at culmination

(CMAI) for western hemlock at age 60 is about 97 cubic feet

per acre. Estimates of site index and yield for Pacific silver fir

have not been made. Among the common forest understory

plants are red huckleberry, blue-leaved huckleberry, and

trailing blackberry.

The main limitation for harvesting of timber is seasonal soil

wetness. A seasonal perched water table limits the use of

equipment to dry periods. Snowpack also restricts the use of

equipment and limits access. Use of wheeled and tracked

equipment when the soil in this unit is wet produces ruts,

compacts the soil, and damages the roots of trees.

Unsurfaced roads and skid trails are sticky when wet, and they

may be impassable during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is readily available on this unit.

Seedling establishment and windthrow hazard are the

main concerns for the production of timber. If seed trees are

present, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. When

openings are made in the canopy, invading brushy plants, if

not controlled, can delay the establishment of natural

reforestation.

Because the rooting depth is restricted by the underlying

glacial till and the seasonal perched water table, trees are

subject to windthrow. Western hemlock, a shallow-rooted

tree, is more commonly subject to windthrow than are more

deeply rooted trees.

The main limitations for homesites are wetness and

steepness of slope in areas where slope is more than 15

percent. Water erosion is a hazard in the steeper areas. Only

the part of the site that is used for construction should be

disturbed. A seasonal high water table is perched above the

glacial till, and drainage is needed if buildings with

basements and crawl spaces are constructed. Foundations

for dwellings require special design to overcome the risk of

frost damage.

The main limitations for septic tank absorption fields are

depth to the glacial till, wetness, and steepness of slope in

areas where the slope is more than 15 percent. Septic tank

absorption lines should be installed on the contour.

This map unit is in capability subclass VIle.

80-Winston gravelly loam, 0 to 3 percent slopes. This

very deep, somewhat excessively drained soil is on terraces

and outwash plains. It formed in glacial outwash
and volcanic ash. Areas are 20 to 60 acres in size. The

larger areas are along major drainageways. The native

vegetation is mainly conifers. Elevation is 200 to 900

feet. The average annual precipitation is about 55 inches,

the average annual air temperature is about 48 degrees F., and

the average frost-free season is 140 to 200 days.

Typically, the surface is covered with a mat of needles,

leaves, twigs, and decomposed litter about 2 inches thick.

The surface layer is dark brown gravelly loam about 3

inches thick. The subsoil is dark brown, strong brown, and

yellowish brown gravelly loam and gravelly fine sandy loam

about 13 inches thick. The upper part of the substratum is

yellowish brown gravelly fine sandy loam about 9 inches

thick. The lower part to a depth of 60 inches or more is very

dark grayish brown extremely gravelly coarse sand. In some

areas the subsoil is very gravelly sandy loam.

Included in this unit are areas of soils that have slopes of

more than 3 percent, Pastik soils on terraces, Ragnar soils

on outwash plains, Sulsavar soils on terraces and alluvial

fans, Tokul soils on till plains, and Rock outcrop. Included

areas make up about 15 percent of the total acreage.

Permeability of this Winston soil is moderate to the

lower part of the substratum and very rapid through it.

Available water capacity is low. Effective rooting depth is 60

inches or more. Runoff is very slow, and the hazard of

water erosion is slight.

This unit is used mainly as woodland. It is also used

for hay and pasture and for homesite development.

Douglas-fir and western hemlock are the main

woodland species on this unit. On the basis of a 100-year site

curve, the mean site index is 167 for Douglas-fir and 164 for

western hemlock. On the basis of a 50-year site curve, the

mean site index is 127 for Douglas-fir and 104 for western

hemlock. The mean annual increment at culmination

(CMAI) is 178 feet per acre for Douglas-fir at age 60 and

262 cubic feet per acre for western hemlock at age 50.

Among the trees of limited extent are western

redcedar and red alder. Among the common forest

understory plants are western swordfern, red huckleberry,

western brackenfern, salal, and trailing blackberry.

The main limitation for harvesting timber is seasonal

soil wetness. Use of wheeled and tracked equipment

when the soil in this unit is wet produces ruts, compacts the

soil, and damages the roots of trees. Unsurfaced roads and

skid trails are soft when wet, and they may be impassable

during rainy periods. Logging roads require suitable surfacing

for year-round use. Rock for road construction is readily

available on this unit.

Reforestation can be accomplished by planting Douglas-fir

seedlings. If seed trees are present, natural reforestation of

cutover areas by red alder occurs readily and that of

western hemlock occurs periodically. When openings are

made in the canopy, invading brushy plants, if not controlled,

can prevent reforestation.

The main limitations for hay and pasture are low available

water capacity and small stones, which can interfere with

cultivation. Use of proper stocking rates, pasture rotation,

and restricted grazing during wet periods helps to keep the

pasture in good condition. Proper grazing practices, weed

control, and fertilizer are needed for maximum quality of

forage. In most years supplemental irrigation is also needed.

Fertilizer is needed for optimum growth of grasses and

legumes.

This unit is suited to homesite development. The main

limitation for septic tank absorption fields is seepage. If the

density of housing is moderate to high, community sewage

systems may be needed to prevent contamination of water

supplies as a result of seepage.

This map unit is in capability subclass Ills.

81-Winston gravelly loam, 3 to 30 percent slopes.

This very deep, somewhat excessively drained soil is on

terraces, terrace escarpments, and outwash plains. It formed

in glacial outwash and volcanic ash. Areas are 5 to 40 acres

in size. The native vegetation is mainly conifers. Elevation is

200 to 900 feet. The average annual precipitation is about 55

inches, the average annual air temperature is about 48

degrees F, and the average frost-free season is 140 to 200

days.

Typically, the surface is covered with a mat of needles,

leaves, twigs, and decomposed litter about 2 inches thick.

The surface layer is dark brown gravelly loam about 3 inches

thick. The subsoil is dark brown, strong brown, and yellowish

brown gravelly loam and gravelly fine sandy loam about 13

inches thick. The upper part of the substratum is yellowish

brown gravelly fine sandy loam about 9 inches thick. The

lower part to a depth of 60 inches or more is very dark

grayish brown extremely gravelly coarse sand. Some

areas have a very gravelly sandy loam subsoil.

Included in this unit are small areas of Pastik soils on

terraces, Ragnar soils on outwash plains, Sulsavar soils

on terraces and alluvial fans, Tokul soils on till plains, and

Rock outcrop. Included areas make up about 15 percent of

the total acreage.

Permeability of this Winston soil is moderate to the lower

part of the substratum and very rapid through it. Available

water capacity is low. Effective rooting depth is 60 inches or

more. Runoff is medium, and the hazard of water erosion is

moderate.

This unit is used mainly as woodland.

Douglas-fir and western hemlock are the main woodland

species on this unit. On the basis of a 100-year site curve, the

mean site index is 167 for Douglas-fir and 164 for western

hemlock. On the basis of a 50-year site curve, the mean site

index is 127 for Douglas-fir and 104 for western hemlock.

The mean annual increment at culmination (CMAI) is 178

cubic feet per acre for Douglas-fir at age 60 and 262 cubic

feet per acre for western hemlock at age 50. Among the

trees of limited extent are western redcedar and red alder.

Among the common forest understory plants are western

swordfern,
red huckleberry, western brackenfern, salal, and trailing

blackberry.

The main limitation for harvesting of timber is

seasonal soil wetness. Use of wheeled and tracked

equipment when the soil in this unit is wet produces ruts,

compacts the soil, and damages the roots of trees.

Unsurfaced roads and skid trails are soft when wet, and they

may be impassable during rainy periods. Logging roads

require suitable surfacing for year-round use. Rock for

road construction is readily available on this unit. Establishing

plant cover on steep road cut and fill slopes reduces

erosion.

Brush competition is the main limitation in the production

of timber. Reforestation can be accomplished by planting

Douglas-fir seedlings. If seed trees are present, natural

reforestation of cutover areas by red alder occurs readily

and that of western hemlock occurs periodically. When

openings are made in the canopy, invading brushy plants,

if not controlled, can prevent reforestation.

The main limitation for homesites is steepness of slope in

areas where slopes are more than 15 percent. The main

limitations for septic tank absorption fields are seepage

and steepness of slope in areas where the slopes are more

than 15 percent. If the density of

housing is moderate to high, community sewage systems may

be needed to prevent contamination of water supplies as

a result of seepage from onsite sewage disposal systems.

This map unit is in capability subclass IVe.

82-Xerorthents, level. This map unit is on till plains.

Most areas are 5 to 40 acres in size. The native vegetation

is mainly conifers. Elevation is 5 to 1,000 feet. The average

annual precipitation is about 40 inches, the average

annual air temperature is about 50 degrees F, and the

average frost-free season is 170 to 190 days.

This unit consists of areas where the surface layer,

subsoil, and substratum have been greatly disturbed,

removed, or replaced with other soil material. Properties

are highly variable within short distances.

Included in this unit are small areas of Alderwood,

Tokul, and Indianola soils. Also included are areas of debris,

such as wood chips from lumber mills.

This unit is used mainly for unpaved parking areas, fill

sites, mobile home parks, athletic fields, and other urban

uses.

Onsite inspection of areas of this unit is necessary to

determine their suitability for intended uses. This map

unit is in capability subclass Vlls.
use and management of the soils

This soil survey is an inventory and evaluation of the

soils in the survey area. It can be used to adjust land uses

to the limitations and potentials of natural resources and

the environment. Also, it can help avoid soil-related

failures in land uses.

In preparing a soil survey, soil scientists, conservationists,

engineers, and others collect extensive field data about the

nature and behavior characteristics of the soils. They collect

data on erosion, droughtiness, flooding, and other factors

that affect various soil uses and management. Field

experience and collected data on soil properties and

performance are used as a basis in predicting soil behavior.

Information in this section can be used to plan the use

and management of soils for crops and pasture; as

rangeland and woodland; as sites for buildings, sanitary

facilities, highways and other transportation systems, and parks

and other recreation facilities; and for wildlife habitat. It can

be used to identify the potentials and limitations of each soil

for specific land uses and to help prevent construction

failures caused by unfavorable soil properties.

Planners and others using soil survey information can

evaluate the effect of specific land uses on productivity and

on the environment in all or part of the survey area. The

survey can help planners to maintain or create a land use

pattern in harmony with the natural soil.

Contractors can use this survey to locate sources of

sand and gravel, roadfill, and topsoil. They can use it to

identify areas where bedrock, wetness, or very firm soil

layers can cause difficulty in excavation.

Health officials, highway officials, engineers, and others may

also find this survey useful. The survey can help them plan

the safe disposal of wastes and locate sites for

pavements, sidewalks, campgrounds, playgrounds, lawns,

and trees and shrubs.

crops and pasture

General management needed for crops and pasture is

suggested in this section. The crops or pasture plants best

suited to the soils, including some not commonly grown in

the survey area, are identified; the system of land capability

classification used by the Soil Conservation Service is

explained; and the estimated yields of the main crops and hay

and pasture plants are listed for each soil.

Planners of management systems for individual fields or

farms should consider the detailed information given

in the description of each soil under "Detailed soil map

units." Specific information can be obtained from the local

office of the Soil Conservation Service or the Cooperative

Extension Service.

About 86,000 acres of Snohomish County Area is used

as cropland, most of which is pasture for livestock (16).

Potatoes, corn, wheat, barley, rhubarb, raspberries, and

blueberries are grown in areas that are drained or where

natural drainage is adequate. Wetness, low soil fertility,

and the hazard of erosion are the main management

concerns.

The McKenna soils in this survey area have a layer of

dense glacial till at a depth of 20 to 40 inches. This glacial

till restricts movement of roots and water and has an effect

on use and management similar to that of a hardpan.

The Indianola, Lynnwood, and Puyallup soils that have

slopes of less than 6 percent are well suited to vegetables

and small fruits. If adequately drained, the mucky soils in this

survey area are well suited to vegetables and berries.

The hazard of erosion is a concern on the Kitsap, Pastik,

and Rober soils that have slopes of more than 2 percent.

Loss of the surface layer reduces fertility and productivity.

Practices to control erosion that provide a protective surface

cover, reduce runoff, and increase the water infiltration rate

are needed.

Soil drainage is needed on about two-thirds of the

acreage used for crops and pasture. Unless the soils are

artificially drained, production of cultivated crops generally is

not feasible. The poorly drained soils in the survey area are

the Bellingham, Custer, McKenna, Norma, Puget, and Sumas

soils; the organic Mukilteo muck; and Terric Medisaprists.

Proper design of both surface and subsurface drainage

systems varies with each kind of soil. A combination of

surface and tile drains is needed in most areas of the poorly

drained and very poorly drained soils. Adequate outlets for

tile drainage systems are difficult to locate on the

Bellingham, Custer, McKenna, and Norma soils.

Organic soils oxidize and subside when the pores are

filled with air; thus, special drainage systems are required to

control the depth and period of drainage. Keeping the water

table at the proper level for crops during the growing season

and raising it to the surface during other times of the year

minimize the oxidation and subsidence of organic soils.
The soils on uplands have low fertility, and they are not so

productive as the soils on flood plains. For good growth of

alfalfa and other crops, applications of lime are needed

to raise the soil reaction to about neutral. Levels of

available phosphorus and potash are low in most of the

soils on uplands.

Information on the proper design of erosion control

practices and drainage systems for each kind of soil in

the survey area is available at the local office of the Soil

Conservation Service. The Cooperative Extension Service can

help in determining the kinds and amounts of fertilizer and

lime to apply.

yields per acre

The average yields per acre that can be expected of the

principal crops under a high level of management are shown in table

5. In any given year, yields may be higher or lower than those

indicated in the table because of variations in rainfall and

other climatic factors.

The yields are based mainly on the experience and records

of farmers, conservationists, and extension agents.

Available yield data from nearby counties and results of

field trials and demonstrations are also considered.

The management needed to obtain the indicated yields of the

various crops depends on the kind of soil and the crop.

Management can include drainage, erosion control, and

protection from flooding; the proper planting and seeding

rates; suitable high-yielding crop varieties; appropriate and

timely tillage; control of weeds, plant diseases, and harmful

insects; favorable soil reaction and optimum levels of

nitrogen, phosphorus, potassium, and trace elements for

each crop; effective use of crop residue, barnyard manure, and

green-manure crops; and harvesting that insures the smallest

possible loss.

For yields of irrigated crops, it is assumed that the

irrigation system is adapted to the soils and to the crops

grown, that good quality irrigation water is uniformly applied

as needed, and that tillage is kept to a minimum.

The estimated yields reflect the productive capacity of

each soil for each of the principal crops. Yields are likely to

increase as new production technology is developed. The

productivity of a given soil compared with that of other

soils, however, is not likely to change.

Crops other than those shown in table 5 are grown in

the survey area, but estimated yields are not listed

because the acreage of such crops is small. The local

office of the Soil Conservation Service or of the

Cooperative Extension Service can provide information

about the management and productivity of the soils.

land capability classification

Land capability classification shows, in a general way, the

suitability of soils for most kinds of field crops (18). Crops

that require special management are excluded. The soils are

grouped according to their limitations for field crops, the

risk of damage if they are used for crops,

and the way they respond to management. The grouping

does not take into account major and generally expensive

landforming that would change slope, depth, or other

characteristics of the soils, nor does it consider possible but

unlikely major reclamation projects. Capability

classification is not a substitute for interpretations designed

to show suitability and limitations of groups of soils for

rangeland, for woodland, and for engineering purposes.

In the capability system, soils are generally grouped at

three levels: capability class, subclass, and unit. Only

class and subclass are used in this survey. These levels are

defined in the following paragraphs.

Capability classes, the broadest groups, are designated by

Roman numerals I through VIII. The numerals indicate

progressively greater limitations and narrower choices for

practical use. The classes are defined as follows:

Class I soils have slight limitations that restrict their

use.

Class II soils have moderate limitations that reduce the

choice of plants or that require moderate conservation

practices.

Class III soils have severe limitations that reduce the

choice of plants or that require special conservation

practices, or both.

Class IV soils have very severe limitations that reduce the

choice of plants or that require very careful management, or

both.

Class V soils are not likely to erode but have other

limitations, impractical to remove, that limit their use.

Class VI soils have severe limitations that make them

generally unsuitable for cultivation.

Class VII soils have very severe limitations that make

them unsuitable for cultivation.

Class VIII soils and miscellaneous areas have limitations

that nearly preclude their use for commercial crop

production.

Capability subclasses are soil groups within one class.

They are designated by adding a small letter, e, w, s, or c, to

the class numeral, for example, Ile. The letter e shows that

the main limitation is risk of erosion unless close-growing

plant cover is maintained; w shows that water in or on the

soil interferes with plant growth or cultivation (in some soils

the wetness can be partly corrected by artificial drainage); s

shows that the soil is limited mainly because it is shallow,

droughty, or stony; and c, used in only some parts of the

United States, shows that the chief limitation is climate that

is very cold or very dry.

In class I there are no subclasses because the soils of this

class have few limitations. Class V contains only the

subclasses indicated by w, s, or c because the soils in class

V are subject to little or no erosion. They have other

limitations that restrict their use to pasture, rangeland,

woodland, wildlife habitat, or recreation.

The capability classification of each map unit is given in

the section "Detailed soil map units."
woodland management and productivity

By Dennis J. Robinson and Robert Whitefield, foresters, and Shirley E.

Perry, biological technician, Soil Conservation Service.

A large part of the survey area is forested. The forest land

is owned and managed mainly by forest industry corporations

and private, nonindustrial owners (5). The forested land totals

about 487,000 acres, of which about 11,000 acres, stocked

mainly with hardwood species, is controlled by the Tulalip

Indians.

There are 21 softwood sawmills, 5 hardwood sawmills, 33

specialty sawmills, and 3 post and piling outlets in the

survey area (6). Both high grade and low grade paper

products for use throughout the county and state are

manufactured from wood chips.

The forest industry has begun using more intensive

management practices for the forest land in the survey

area. Management of the nonindustrial areas is also

improving as a result of the use of conservation programs.

Historically, the native stands of trees in the survey

area were primarily conifers; however, deciduous trees now

grow on a significant part of the acreage. Douglas-fir

and western hemlock are the dominant conifers, but

significant numbers of western redcedar also occur. Old

growth redcedar is in great demand for specialty

products, but only a few areas of western redcedar are

being established by public and private woodland managers.

Red alder is the main deciduous tree in the survey

area. It grows in pure stands and in stands mixed with

other deciduous and coniferous species. Red alder commonly

invades logged-off areas, and it becomes dominant unless

intensive management practices are used. A barren mineral

soil, an adequate seed source, and an abundant supply of

moisture are needed for establishment of red alder.

Soils vary in their ability to produce wood fiber. Depth to

a restrictive layer, soil fertility, texture, and available water

capacity influence growth. Elevation, aspect, the kind of soil, and

climate determine the kinds of trees that can be grown on a

given site.

Woodland management of coniferous species is concentrated

in areas that are at intermediate to high elevations. These

areas are well stocked with pure stands of hardwoods or

mixed stands of hardwoods and conifers.

The large valleys of rivers that flow east to west, such as

the Stillaguamish and Skykomish Rivers, act as warm air

funnels. They collect and trap warm air from the prevailing

westerly winds during the winter. As a result of this, pure

stands of Douglas-fir can be established in areas further

to the east that have higher precipitation, are at a higher

elevation, and are cooler. These areas otherwise would

be suitable only for western hemlock.

Pure stands of western hemlock and mixed stands of

western hemlock, Douglas-fir, and western redcedar are

in areas further to the east at higher elevations. Western

hemlock persists because of its ability to regenerate under a

closed canopy and its proliferate seed production. Still

further east, where the elevation and available moisture

increase and the growing season decreases, stands of

western hemlock and Pacific silver fir occur. Stands of Pacific

silver fir and mountain hemlock are at elevations of more

than 2,800 feet. Regeneration of most species is difficult at

these higher elevations, and Pacific silver fir commonly is the

only species that can become established in significant

amounts.

Soil surveys are becoming increasingly more important to

woodland managers as they seek ways of increasing the

productivity of forest land. Some soils respond better to

fertilization, some are more susceptible to landslides and

erosion after roadbuilding and harvesting of trees, and some

require special management for harvesting and reforestation.

In the section "Detailed soil map units" of this survey,

each map unit suitable for producing wood crops gives

information on woodland productivity, common forest

understory plants, limitations for harvesting timber, and

concerns for producing timber. Table 6 summarizes the

forestry information given in these map units, and it can be

used as a reference for important woodland interpretations.

The table lists the map unit symbol and the ordination

(woodland suitability) symbol for each soil. Soils that have

the same ordination symbol require the same general

woodland management and have about the same potential

productivity.

The first part of the ordination symbol, a number,

indicates the potential productivity of the soils for important

trees. The number 1 indicates very high productivity; 2, high;

3, moderately high; 4, moderate; and 5, 6, and 7, low. This

number corresponds to the 50-year site curve indexes

established for Douglas-fir, red alder, and western hemlock.

The second part of the symbol, a letter, indicates the major

kind of soil limitation for tree growth and management. The

letter w indicates excessive water in or on the soil; d,

restricted rooting depth; s, sandy texture; f, high content of

coarse fragments in the soil profile; and r, steep slopes. The

letter o indicates that few if any limitations or restrictions are

significant.

In table 6 the soils are rated for a number of factors to

be considered in management. Slight, moderate, and severe

are used to indicate the degree of the major soil limitations.

Equipment limitation ratings refer to the soil characteristics

that restrict year-round or seasonal use of equipment. A rating

of slight indicates that use is not limited to a particular kind

of equipment or time of year; moderate indicates a short

seasonal limitation because of soil wetness, a fluctuating

water table, or some other factor; and severe indicates a

seasonal limitation, a need for special equipment such as a

cable yarding system, or a hazard in the use of equipment.
Steepness of slope and soil wetness are the main

limitations for use of equipment. As the slope becomes

steeper and longer, use of wheeled equipment becomes more

difficult, and only tracked equipment is suitable for use in

some areas. On the steepest slopes, even tracked equipment

does not operate safely, and more sophisticated systems are

needed. Soil wetness, especially in combination with fine texture,

can severely limit the use of equipment and make harvesting

practical only during the dry summer months.

Seedling mortality ratings refer to the probability of

death of natural or planted tree seedlings as influenced by

the kinds of soil and topography. Plant competition is not

considered in the ratings. The ratings apply to seedlings

from good stock that are properly planted or to natural

regeneration during a period of sufficient soil moisture.

A rating of slight indicates that no problem of mortality is

expected under normal conditions; moderate indicates that

some problems can be expected and extra precautions are

advisable; and severe indicates that mortality is high and extra

precautions are essential for successful reforestation. Soil

wetness; droughtiness of the surface layer, especially on

south- and southwest-facing slopes; and areas of soils on

ridgetops are concerns for seedling mortality. Larger than normal

planting stock, special site preparation, surface drainage, or

reinforcement planting may be needed to overcome these

limitations.

Windthrow hazard ratings are based on soil

characteristics that affect the development of tree roots and

the ability of the soil to hold trees firmly. Restricted rooting

depth because of the high water table and the underlying

bedrock or poor anchoring of roots because of a loose

surface layer and subsoil result in windthrow. A rating of

slight indicates that trees normally are not blown down or

uprooted by wind, but strong winds may break trees; moderate,

some trees are blown down during periods of excessive

wetness and strong winds; and severe, many trees are blown

down during periods of soil wetness and moderate or strong

winds. If the windthrow hazard rating is moderate or severe, care

in thinning the edges of woodland stands, periodic salvage

of windthrown trees, and adequate roads and trails for

salvage operations are needed.

Plant competition ratings refer to the probability of the

invasion of brushy plants where there are openings in the tree

canopy. A rating of slight indicates that unwanted brushy

plants are not likely to delay natural reforestation or

restrict the development of planted seedlings; moderate

indicates that competition will delay reforestation by native

plants or planted seedlings; and severe indicates that

competition is expected to prevent reforestation. If the

rating is moderate or severe, careful and thorough

cleanup after harvesting is needed to prepare the soil for

reforestation and mechanical or chemical brush treatment

may be needed to retard the growth of brush and allow

seedlings to develop.

A favorable climate and productive soils encourage plant

competition. Generally, the hazard of brush invasion is lower

at higher elevations. In many areas the extent of plant

competition can be predicted by determining the quantity

and proximity of seed sources of undesirable plants.

The potential productivity of common trees on a soil is

expressed as a site index. This index is determined by taking

height and age measurements of selected trees in stands of

a given species. The "50-year site curve" index is given in

table 6. Both the "50-year site curve" index and the "100-

year site curve" index are given in the section "Detailed soil

map units." The procedure and technique for calculating the

site indexes are given in the site index tables used for this

survey area (4, 12, 13, 21, 22). The site index applies to fully

stocked, even-aged, unmanaged stands of trees. The highest

timber yields, expressed in board feet or cubic feet per acre,

can be expected from soils that have the highest site

indexes. Site indexes can be converted into estimated yields

at various ages by using the appropriate yield table (7, 8, 9).

Common trees are listed in the order of their dominance on

the soils. Generally, only one or two woodland species are

dominant.

Trees to plant are those that are used for reforestation or

natural regeneration. Species listed are suited to the soils

and to commercial wood production.

recreation

The soils of the survey area are rated in table 7 according

to limitations that affect their suitability for recreation. The

ratings are based on restrictive soil features, such as

wetness, slope, and texture of the surface layer.

Susceptibility to flooding is considered. Not considered in the

ratings, but important in evaluating a site, are the location

and accessibility of the area, the size and shape of the area

and its scenic quality, vegetation, access to water, potential

water impoundment sites, and access to public sewerlines.

The capacity of the soil to absorb septic tank effluent and

the ability of the soil to support vegetation are also

important. Soils subject to flooding are limited for recreation

use by the duration and intensity of flooding and the season

when flooding occurs. In planning recreation facilities, onsite

assessment of the height, duration, intensity, and frequency

of flooding is essential.

In table 7, the degree of soil limitation is expressed as

slight, moderate, or severe. Slight means that soil properties

are generally favorable and that limitations are minor and

easily overcome. Moderate means that limitations can be

overcome or alleviated by planning, design, or special

maintenance. Severe means that soil properties are

unfavorable and that limitations can be offset only by costly

soil reclamation, special design, intensive maintenance,

limited use, or by a combination of these measures.

The information in table 7 can be supplemented by

other information in this survey, for example,
interpretations for septic tank absorption fields in table 10 and

interpretations for dwellings without basements and for local

roads and streets in table 9.

Camp areas require site preparation such as shaping and

leveling the tent and parking areas, stabilizing roads and

intensively used areas, and installing sanitary facilities and

utility lines. Camp areas are subject to heavy foot traffic and

some vehicular traffic. The best soils have mild slopes and

are not wet or subject to flooding during the period of use.

The surface has few or no stones or boulders, absorbs

rainfall readily but remains firm, and is not dusty when dry.

Strong slopes and stones or boulders can greatly increase

the cost of constructing campsites.

Picnic areas are subject to heavy foot traffic. Most vehicular

traffic is confined to access roads and parking areas. The

best soils for picnic areas are firm when wet, are not dusty when

dry, are not subject to flooding during the period of use, and do

not have slopes or stones or boulders that increase the

cost of shaping sites or of building access roads and parking

areas.

Playgrounds require soils that can withstand intensive foot

traffic. The best soils are almost level and are not wet or subject

to flooding during the season of use. The surface is free of

stones and boulders, is firm after rains, and is not dusty

when dry. If grading is needed, the depth of the soil over

bedrock or a hardpan should be considered.

Paths and trails for hiking, horseback riding, and bicycling

should require little or no cutting and filling. The best soils are

not wet, are firm after rains, are not dusty when dry, and are

not subject to flooding more than once a year during the

period of use. They have moderate slopes and few or no

stones or boulders on the surface.

Golf fairways are subject to heavy foot traffic and some

light vehicular traffic. Cutting or filling may be required. The

best soils for use as golf fairways are firm when wet, are not

dusty when dry, and are not subject to prolonged flooding during

the period of use. They have moderate slopes and no stones

or boulders on the surface. The suitability of the soil for tees

or greens is not considered in rating the soils.

wildlife habitat

By Ivan L. Lines, Jr., biologist, Soil Conservation Service.

Snohomish County Area has a wide variety of wildlife habitat

that supports many species of wildlife. It varies from saltwater

tidelands and shorelines on the Puget Sound to alpine plant

communities along the crest of the Cascade Range.

Elevation of these areas ranges from sea level to more

than 10,000 feet.

Several miles of saltwater shorelines and thousands of

acres of tidelands provide habitat for oysters, clams, crabs,

and numerous saltwater and freshwater fish. Many species

of waterfowl and shorebirds, such as

brant, wigeon, gulls, sandpipers, and plovers, also use

these areas.

Farming on most of the fertile soils on lowlands, along

flood plains, and in many upland areas provides habitat for

openland wildlife such as pheasant, California quail, and

rabbits. These areas also commonly supply some habitat for

woodland wildlife and waterfowl.

Much of the uplands in the area are covered by extensive

stands of Douglas-fir and red alder, and the wet soils and

riparian corridors support bigleaf maple, cottonwood, and

dogwood. These woodland areas have a diverse understory of

salal, Oregon-grape, huckleberry, and rhododendron. The

areas provide habitat for woodland wildlife such as blacktailed deer, black bear, woodpeckers, ruffed grouse, and

mountain beaver. They also provide food and cover for birds and

mammals that mainly feed in forest openings and on

cropland.

Numerous lakes and farm ponds support trout and

warmwater fish. Most of the streams that flow into the Puget

Sound once contained large runs of salmon, steelhead,

and sea-run cutthroat trout. Some of the runs have been

eliminated or reduced, but many streams still support some

anadromous fish.

The city of Everett and the proximity of the survey area to the

Seattle metropolitan area have resulted in increased urban,

suburban, and recreational development. This development

and the timber production and farming activities in the area have

a great impact on wildlife habitat. Few of the soils in the area

are managed specifically for wildlife habitat; therefore,

management of the soils used mainly for other purposes

largely determines the amount and quality of habitat and the

abundance of wildlife.

Proper management of the cropland and hay and

pasture on general soil map units 1, 2, and 3 can

enhance wildlife habitat. Suitable practices are planting

cover crops; returning crop residue to the soil; leaving

strips of undisturbed vegetation along shorelines and

streambanks; proper handling of livestock waste to

prevent pollution of water; and proper handling of

pesticides and chemicals.

Some soils in the area are poorly drained and are suited

to the development of ponds and wetland areas. Practices

such as building dikes, water control structures, and islands

can create or improve wetland wildlife habitat.

Use of suitable management practices in the woodland

areas of units 2, 3, 4, 5, and 6 can also enhance wildlife

habitat. Small-scale clearcutting helps to create a diversity

of successional stages in the vegetation, which results in a

wide variety of wildlife habitat. Leaving strips of undisturbed

vegetation along stream corridors and shorelines helps to

prevent pollution of water sources and destruction of aquatic

habitat, and these strips of riparian vegetation can be used

as habitat for wildlife. Leaving snags standing provides habitat

for cavity nesting birds and provides food for all types of wildlife.

Logging practices that
reduce erosion and prevent sediment and debris from

entering streams should be used. Disturbed areas, such as

roads, skid trails, and burns, need to be seeded to grasses

and legumes to reduce water pollution.

Increasing acreages of the soils in units 1, 2, and 3 are

being used for urban development, and careful planning is

needed to preserve as much wildlife habitat as possible.

Landscaping urban areas can beautify the areas as well as

provide habitat for wildlife. Control of sediment from

construction sites is needed to prevent disturbance of

adjacent areas and water pollution. Proper disposal systems

for sewage, storm runoff, and other possibly harmful pollutants

is also needed. Strips of riparian vegetation should be

maintained to prevent streambank erosion, intercept

sediment, and provide areas of wildlife habitat.

Soils affect the kind and amount of vegetation that is

available to wildlife as food and cover. They also affect the

construction of water impoundments. The kind and

abundance of wildlife depend largely on the amount and

distribution of food, cover, and water. Wildlife habitat

can be created or improved by planting appropriate

vegetation, by maintaining the existing plant cover, or by

promoting the natural establishment of desirable plants.

In table 8, the soils in the survey area are rated according

to their potential for providing habitat for various kinds of

wildlife. This information can be used in planning parks, wildlife

refuges, nature study areas, and other developments for

wildlife; in selecting soils that are suitable for establishing,

improving, or maintaining specific elements of wildlife habitat; and

in determining the intensity of management needed for

each element of the habitat.

The potential of the soil is rated good, fair, poor, or very

poor. A rating of good indicates that the element or kind of

habitat is easily established, improved, or maintained. Few or no

limitations affect management, and satisfactory results can

be expected. A rating of fair indicates that the element or

kind of habitat can be established, improved, or maintained

in most places. Moderately intensive management is required for

satisfactory results. A rating of poor indicates that limitations

are severe for the designated element or kind of habitat.

Habitat can be created, improved, or maintained in most places,

but management is difficult and must be intensive. A rating of

very poor indicates that restrictions for the element or kind of

habitat are very severe and that unsatisfactory results can be

expected. Creating, improving, or maintaining habitat is impractical

or impossible.

The elements of wildlife habitat are described in the

following paragraphs.

Grain and seed crops are domestic grains and seedproducing herbaceous plants. Soil properties and features

that affect the growth of grain and seed crops are depth of

the root zone, texture of the surface layer, available water

capacity, wetness, slope, surface stoniness, and flood

hazard. Soil temperature and soil

moisture are also considerations. Examples of grain and seed

crops are corn, wheat, oats, and barley.

Grasses and legumes are domestic perennial grasses

and herbaceous legumes. Soil properties and features that affect

the growth of grasses and legumes are depth of the root

zone, texture of the surface layer, available water capacity,

wetness, surface stoniness, flood hazard, and slope. Soil

temperature and soil moisture are also considerations.

Examples of grasses and legumes are fescue, orchardgrass,

bromegrass, clover, and alfalfa.

Wild herbaceous plants are native or naturally

established grasses and forbs, including weeds. Soil properties

and features that affect the growth of these plants are

depth of the root zone, texture of the surface layer,

available water capacity, wetness, surface stoniness, and

flood hazard. Soil temperature and soil moisture are also

considerations. Examples of wild herbaceous plants are

western swordfern, western brackenfern, pacific trillium; and

fireweed.

Coniferous plants furnish browse, seeds, and cones. Soil

properties and features that affect the growth of coniferous

trees, shrubs, and ground cover are depth of the root

zone, available water capacity, and wetness. Examples

of coniferous plants are Pacific fir, western hemlock,

noble fir, and western red cedar.

Shrubs are bushy woody plants that produce fruit, buds,

twigs, bark, and foliage. Soil properties and features that

affect the growth of shrubs are depth of the root zone,

available water capacity, salinity, and soil moisture.

Examples of shrubs are salal; red huckleberry, Oregon grape,

salmonberry, snowberry, and blackberry.

Wetland plants are annual and perennial wild herbaceous

plants that grow on moist or wet sites. Submerged or floating

aquatic plants are excluded. Soil properties and features

affecting wetland plants are texture of the surface layer,

wetness, reaction, salinity, slope, and surface stoniness.

Examples of wetland plants are smartweed, wild millet,

cattail, saltgrass, rushes, sedges and reeds.

Shallow water areas have an average depth of less

than 5 feet. Some are naturally wet areas. Others are

created by dams, levees, or other water-control

structures. Soil properties and features affecting shallow

water areas are depth to bedrock, wetness, surface

stoniness, slope, and permeability. Examples of shallow water

areas are marshes, waterfowl feeding areas, and

ponds.

The habitat for various kinds of wildlife is described in the

following paragraphs.

Habitat for openland wildlife consists of cropland,

pasture, meadows, and areas that are overgrown with

grasses, herbs, shrubs, and vines. These areas produce

grain and seed crops, grasses and legumes, and wild

herbaceous plants. The wildlife attracted to these areas

include California quail, pheasant, meadowlark, field

sparrow, cottontail, and red fox.

Habitat for woodland wildlife consists of areas of

deciduous plants or coniferous plants or both and
associated grasses, legumes, and wild herbaceous plants.

Wildlife attracted to these areas include ruffed grouse,

thrushes, woodpeckers, squirrels, gray fox, raccoon, blacktailed deer, and black bear.

Habitat for wetland wildlife consists of open, marshy or

swampy shallow water areas. Some of the wildlife attracted

to such areas are ducks, geese, shore birds, muskrat, mink,

and beaver.

engineering

This section provides information for planning land uses

related to urban development and to water management. Soils

are rated for various uses, and the most limiting features are

identified. The ratings are given in the following tables: Building

site development, Sanitary facilities, Construction materials,

and Water management. The ratings are based on observed

performance of the soils and on the estimated data and

test data in the "Soil properties" section.

Information in this section is intended for land use planning,

for evaluating land use alternatives, and for planning site

investigations prior to design and construction. The

information, however, has limitations. For example,

estimates and other data generally apply only to that part

of the soil within a depth of 5 or 6 feet. Because of the

map scale, small areas of different soils may be included

within the mapped areas of a specific soil.

The information is not site specific and does not eliminate

the need for onsite investigation of the soils or for testing

and analysis by personnel experienced in the design and

construction of engineering works.

Government ordinances and regulations that restrict certain

land uses or impose specific design criteria were not considered

in preparing the information in this section. Local ordinances

and regulations need to be considered in planning, in site

selection, and in design.

Soil properties, site features, and observed performance were

considered in determining the ratings in this section. During

the fieldwork for this soil survey, determinations were made

about grain-size distribution, liquid limit, plasticity index, soil reaction,

depth to bedrock, hardness of bedrock within 5 to 6 feet of

the surface, soil wetness, depth to a seasonal high water

table, slope, likelihood of flooding, natural soil structure

aggregation, and soil density. Data were collected about

kinds of clay minerals, mineralogy of the sand and silt

fractions, and the kind of adsorbed cations. Estimates

were made for erodibility, permeability, corrosivity, shrink-swell

potential, available water capacity, and other behavioral

characteristics affecting engineering uses.

This information can be used to (1) evaluate the potential of

areas for residential, commercial, industrial, and recreation uses;

(2) make preliminary estimates of construction conditions; (3)

evaluate alternative routes for roads, streets, highways,

pipelines, and underground cables; (4) evaluate alternative sites

for sanitary landfills,

septic tank absorption fields, and sewage lagoons; (5) plan

detailed onsite investigations of soils and geology; (6)

locate potential sources of gravel, sand, earthfill, and

topsoil; (7) plan drainage systems, irrigation systems, ponds,

terraces, and other structures for soil and water

conservation; and (8) predict performance of proposed

small structures and pavements by comparing the performance

of existing similar structures on the same or similar soils.

The information in the tables, along with the soil maps,

the soil descriptions, and other data provided in this survey

can be used to make additional interpretations.

Some of the terms used in this soil survey have a

special meaning in soil science and are defined in the

Glossary.

building site development

Table 9 shows the degree and kind of soil limitations that

affect shallow excavations, dwellings with and without

basements, small commercial buildings, local roads and streets,

and lawns and landscaping. The limitations are considered

slight if soil properties and site features are generally

favorable for the indicated use and limitations are minor

and easily overcome; moderate if soil properties or site

features are not favorable for the indicated use and special

planning, design, or maintenance is needed to overcome or

minimize the limitations; and severe if soil properties or site

features are so unfavorable or so difficult to overcome that

special design, significant increases in construction costs,

and possibly increased maintenance are required. Special

feasibility studies may be required where the soil

limitations are severe.

Shallow excavations are trenches or holes dug to a

maximum depth of 5 or 6 feet for basements, graves, utility

lines, open ditches, and other purposes. The ratings are

based on soil properties, site features, and observed

performance of the soils. The ease of digging, filling, and

compacting is affected by the depth to bedrock, a cemented

pan, or a very firm dense layer; stone content; soil texture;

and slope. The time of the year that excavations can be

made is affected by the depth to a seasonal high water table

and the susceptibility of the soil to flooding. The resistance

of the excavation walls or banks to sloughing or caving is

affected by soil texture and the depth to the water table.

Dwellings and small commercial buildings are

structures built on shallow foundations on undisturbed soil.

The load limit is the same as that for single-family dwellings

no higher than three stories. Ratings are made for small

commercial buildings without basements, for dwellings

with basements, and for dwellings without basements. The

ratings are based on soil properties, site features, and

observed performance of the soils. A high water table,

flooding, shrink-swell potential, and organic layers can cause

the movement of footings. A high water table, depth to

bedrock or to a cemented pan, large
stones, and flooding affect the ease of excavation and

construction. Landscaping and grading that require cuts

and fills of more than 5 to 6 feet are not considered.

Local roads and streets have an all-weather surface and

carry automobile and light truck traffic all year. They have a

subgrade of cut or fill soil material, a base of gravel, crushed rock,

or stabilized soil material, and a flexible or rigid surface. Cuts

and fills are generally limited to less than 6 feet. The ratings are

based on soil properties, site features, and observed

performance of the soils. Depth to bedrock or to a cemented

pan, a high water table, flooding, large stones, and slope

affect the ease of excavating and grading. Soil strength (as

inferred from the engineering classification of the soil), shrinkswell potential, frost action potential, and depth to a high

water table affect the traffic supporting capacity.

Lawns and landscaping require soils on which turf and

ornamental trees and shrubs can be established and

maintained. The ratings are based on soil properties, site

features, and observed performance of the soils. Soil

reaction, a high water table, depth to bedrock or to a

cemented pan, the available water capacity in the upper 40

inches, and the content of salts, sodium, and sulfidic

materials. affect plant growth. Flooding, wetness, slope, stoniness,

and the amount' of sand, clay, or organic matter in the surface

layer affect trafficability after vegetation is established.

sanitary facilities

Table 10 shows the degree and the kind of soil limitations

that affect septic tank absorption fields, sewage lagoons,

and sanitary landfills. The limitations are considered slight

if soil properties and site features are generally favorable

for the indicated use and limitations are minor and easily

overcome; moderate if soil properties or site features are

not favorable for the indicated use and special planning,

design, or maintenance is needed to overcome or minimize

the limitations; and severe if soil properties or site features

are so unfavorable or so difficult to overcome that special

design, significant increases in construction costs, and

possibly increased maintenance are required.

Table 10 also shows the suitability of the soils for use as

daily cover for landfills. A rating of good indicates that soil

properties and site features are favorable for the use and good

performance and low maintenance can be expected; fair

indicates that soil properties and site features are

moderately favorable for the use and one or more soil

properties or site features make the soil less desirable than

the soils rated good; and poor indicates that one or more

soil properties or site features are unfavorable for the use

and overcoming the unfavorable properties requires special

design, extra maintenance, or costly alteration.

Septic tank absorption fields are areas in which

effluent from a septic tank is distributed into the soil

through subsurface tiles or perforated pipe. Only that

part of the soil between depths of 24 and 72 inches is

evaluated. The ratings are based on soil properties, site features,

and observed performance of the soils. Permeability, a high

water table, depth to bedrock or to a cemented pan, and

flooding affect absorption of the effluent. Large stones and

bedrock or a cemented pan interfere with installation.

Unsatisfactory performance of septic tank absorption

fields, including excessively slow absorption of effluent,

surfacing of effluent, and hillside seepage, can affect public

health. Ground water can be polluted if highly permeable sand

and gravel or fractured bedrock is less than 4 feet below the

base of the absorption field, if slope is excessive, or if the

water table is near the surface. There must be unsaturated soil

material beneath the absorption field to effectively filter the

effluent. Many local ordinances require that this material be of a

certain thickness.

Sewage lagoons are shallow ponds constructed to hold

sewage while aerobic bacteria decompose the solid and liquid

wastes. Lagoons should have a nearly level floor surrounded by cut

slopes or embankments of compacted soil. Lagoons generally

are designed to hold the sewage within a depth of 2 to 5

feet. Nearly impervious soil material for the lagoon floor and sides

is required to minimize seepage and contamination of ground

water.

Table 10 gives ratings for the natural soil that makes up the

lagoon floor. The surface layer and, generally, 1 or 2 feet of

soil material below the surface layer are excavated to provide

material for the embankments. The ratings are based on soil

properties, site features, and observed performance of the soils.

Considered in the ratings are slope, permeability, a high water

table, depth to bedrock or to a cemented pan, flooding, large

stones, and content of organic matter.

Excessive seepage due to rapid permeability of the soil or a

water table that is high enough to raise the level of sewage in the

lagoon causes a lagoon to function unsatisfactorily. Pollution

results if seepage is excessive or if floodwater overtops the

lagoon. A high content of organic matter is detrimental to

proper functioning of the lagoon because it inhibits aerobic

activity. Slope, bedrock, and cemented pans can cause

construction problems, and large stones can hinder compaction of

the lagoon floor.

Sanitary landfills are areas where solid waste is disposed

of by burying it in soil. There are two types of landfill-trench

and area. In a trench landfill, the waste is placed in a trench. It is

spread, compacted, and covered daily with a thin layer of soil

excavated at the site. In an area landfill, the waste is placed in

successive layers on the surface of the soil. The waste is

spread, compacted, and covered daily with a thin layer of soil

from a source away from the site.

Both types of landfill must be able to bear heavy

vehicular traffic. Both types involve a risk of ground water

pollution. Ease of excavation and revegetation needs

to be considered.
The ratings in table 10 are based on soil properties, site

features, and observed performance of the soils.

Permeability, depth to bedrock or to a cemented pan, a high

water table, slope, and flooding affect both types of landfill.

Texture, stones and boulders, highly organic layers, soil

reaction, and content of salts and sodium affect trench

type landfills. Unless otherwise stated, the ratings apply only

to that part of the soil within a depth of about 6 feet. For

deeper trenches, a limitation rated slight or moderate may not

be valid. Onsite investigation is needed.

Daily cover for landfill is the soil material that is used to

cover compacted solid waste in an area type sanitary landfill.

The soil material is obtained offsite, transported to the

landfill, and spread over the waste.

Soil texture, wetness, coarse fragments, and slope affect the

ease of removing and spreading the material during wet

and dry periods. Loamy or silty soils that are free of large

stones or excess gravel are the best cover for a landfill.

Clayey soils are sticky or cloddy and are difficult to spread;

sandy soils are subject to soil blowing.

After soil material has been removed, the soil material

remaining in the borrow area must be thick enough over

bedrock, a cemented pan, or the water table to permit

revegetation. The soil material used as final cover for a

landfill should be suitable for plants. The surface layer

generally has the best workability, more organic matter, and the

best potential for plants. Material from the surface layer

should be stockpiled for use as the final cover.

construction materials

Table 11 gives information about the soils as a source of

roadfill, sand, gravel, and topsoil. The soils are rated good,

fair, or poor as a source of roadfill and topsoil. They are

rated as a probable or improbable source of sand and

gravel. The ratings are based on soil properties and site

features that affect the removal of the soil and its use as

construction material. Normal compaction, minor

processing, and other standard construction practices are

assumed. Each soil is evaluated to a depth of 5 or 6 feet.

Roadfill is soil material that is excavated in one place and

used in road embankments in another place. In this table,

the soils are rated as a source of roadfill for low

embankments, generally less than 6 feet high and less

exacting in design than higher embankments.

The ratings are for the soil material below the surface

layer to a depth of 5 or 6 feet. It is assumed that soil layers

will be mixed during excavating and spreading. Many soils

have layers of contrasting suitability within their profile. The

table showing engineering index properties provides detailed

information about each soil layer. This information can help

determine the suitability of each layer for use as roadfill. The

performance of soil after it is stabilized with lime or cement

is not considered in the ratings.

The ratings are based on soil properties, site features, and

observed performance of the soils. The thickness of suitable

material is a major consideration. The ease of excavation is

affected by large stones, a high water table, and slope. How

well the soil performs in place after it has been compacted

and drained is determined by its strength (as inferred from

the engineering classification of the soil) and shrink-swell

potential.

Soils rated good contain significant amounts of sand or

gravel or both. They have at least 5 feet of suitable material,

low shrink-swell potential, few cobbles and stones, and

slopes of 15 percent or less. Depth to the water table is

more than 3 feet. Soils rated fair are more than 35 percent

silt- and clay-sized particles and have a plasticity index of

less than 10. They have moderate shrink-swell potential,

slopes of 15 to 25 percent, or many stones. Depth to the

water table is 1 to 3 feet. Soils rated poor have a plasticity

index of more than 10, a high shrink-swell potential, many

stones, or slopes of more than 25 percent. They are wet,

and the depth to the water table is less than 1 foot. They

may have layers of suitable material, but the material is less

than 3 feet thick.

Sand and gravel are natural aggregates suitable for

commercial use with a minimum of processing. Sand and

gravel are used in many kinds of construction. Specifications

for each use vary widely. In table 11, only the probability of

finding material in suitable quantity is evaluated. The

suitability of the material for specific purposes is not

evaluated, nor are factors that affect excavation of the

material.

The properties used to evaluate the soil as a source of

sand or gravel are gradation of grain sizes (as indicated by

the engineering classification of the soil), the thickness of

suitable material, and the content of rock fragments. Kinds

of rock, acidity, and stratification are given in the soil series

descriptions. Gradation of grain sizes is given in the table on

engineering index properties.

A soil rated as a probable source has a layer of clean

sand or gravel or a layer of sand or gravel that is up to 12

percent silty fines. This material must be at least 3 feet thick

and less than 50 percent, by weight, large stones. All other

soils are rated as an improbable source. Coarse fragments

of soft bedrock, such as shale and siltstone, are not

considered to be sand and gravel.

Topsoil is used to cover an area so that vegetation can be

established and maintained. The upper 40 inches of a soil is

evaluated for use as topsoil. Also evaluated is the

reclamation potential of the borrow area.

Plant growth is affected by toxic material and by such

properties as soil reaction, available water capacity, and

fertility. The ease of excavating, loading, and spreading is

affected by rock fragments, slope, a water table, soil

texture, and thickness of suitable material. Reclamation of

the borrow area is affected by slope, a water table, rock

fragments, bedrock, and toxic material.

Soils rated good have friable loamy material to a depth of

at least 40 inches. They are free of stones and
cobbles, have little or no gravel, and have slopes of less

than 8 percent. They are low in content of soluble salts, are

naturally fertile or respond well to fertilizer, and are not so

wet that excavation is difficult.

Soils rated fair are sandy soils, loamy soils that have a

relatively high content of clay, soils that have only 20 to 40

inches of suitable material, soils that have an appreciable

amount of gravel, stones, or soluble salts, or soils that

have slopes of 8 to 15 percent. The soils are not so wet that

excavation is difficult.

Soils rated poor are very sandy or clayey, have less than 20

inches of suitable material, have a large amount of

gravel, stones, or soluble salts, have slopes of more than 15

percent, or have a seasonal water table at or near the

surface.

The surface layer of most soils is generally preferred

for topsoil because of its organic matter content. Organic

matter greatly increases the absorption and retention of

moisture and nutrients for plant growth.

water management

Table 12 gives information on the soil properties and site

features that affect water management. The degree and

kind of soil limitations are given for pond reservoir areas;

embankments, dikes, and levees; and aquifer-fed excavated

ponds. The limitations are considered slight if soil properties

and site features are generally favorable for the indicated use

and limitations are minor and are easily overcome; moderate

if soil properties or site features are not favorable for the

indicated use and special planning, design, or maintenance is

needed to overcome or minimize the limitations; and severe if soil

properties or site features are so unfavorable or so difficult

to overcome that special design, significant increase in

construction costs, and possibly increased maintenance are

required.

This table also gives for each soil the restrictive features

that affect drainage, irrigation, and terraces and diversions.

Pond reservoir areas hold water behind a dam or

embankment. Soils best suited to this use have low seepage

potential in the upper 60 inches. The seepage potential is

determined by the permeability of the soil and the depth to

fractured bedrock or other permeable material. Excessive

slope can affect the storage capacity of the reservoir area.

 Embankments, dikes, and levees are raised structures

of soil material, generally less than 20 feet high,

constructed to impound water or to protect land against

overflow. In this table, the soils are rated as a source of

material for embankment fill. The ratings apply to the soil

material below the surface layer to a depth of about 5 feet. It

is assumed that soil layers will be uniformly mixed and

compacted during construction.

The ratings do not indicate the ability of the natural

soil to support an embankment. Soil properties to a

depth even greater than the height of the embankment can

affect performance and safety of the embankment.

Generally, deeper onsite investigation is needed to

determine these properties.

Soil material in embankments must be resistant to

seepage, piping, and erosion and have favorable compaction

characteristics. Unfavorable features include less than 5 feet

of suitable material and a high content of stones or boulders,

organic matter, or salts or sodium. A high water table affects

the amount of usable material. It also affects trafficability.

Aquifer-fed excavated ponds are pits or dugouts that

extend to a ground-water aquifer or to a depth below a

permanent water table. Excluded are ponds that are fed

only by surface runoff and embankment ponds that impound

water 3 feet or more above the original surface. Excavated

ponds are affected by depth to a permanent water table,

permeability of the aquifer, and quality of the water as

inferred from the salinity of the soil. Depth to bedrock and

the content of large stones affect the ease of excavation.

Drainage is the removal of excess surface and subsurface

water from the soil. How easily and effectively the soil is

drained depends on the depth to bedrock, to a cemented

pan, or to other layers that affect the rate of water

movement; permeability; depth to a high water table or depth

of standing water if the soil is subject to ponding; slope;

susceptibility to flooding; subsidence of organic layers; and

potential frost action. Excavating and grading and the stability

of ditchbanks are affected by depth to bedrock or to a

cemented pan, large stones, slope, and the hazard of

cutbanks caving. The productivity of the soil after drainage is

adversely affected by extreme acidity or by toxic substances

in the root zone, such as salts, sodium, or sulfur.

Availability of drainage outlets is not considered in the

ratings.

Irrigation is the controlled application of water to

supplement rainfall and support plant growth. The design and

management of an irrigation system are affected by depth to

the water table, the need for drainage, flooding, available

water capacity, intake rate, permeability, erosion hazard, and

slope. The construction of a system is affected by large

stones and depth to bedrock or to a cemented pan. The

performance of a system is affected by the depth of the root

zone, the amount of salts or sodium, and soil reaction.

Terraces and diversions are embankments or a

combination of channels and ridges constructed across

a slope to reduce erosion and conserve moisture by

intercepting runoff. Slope, wetness, large stones, and depth

to bedrock or to a cemented pan affect the construction of

terraces and diversions. A restricted rooting depth, a severe

hazard of wind or water erosion, an excessively coarse

texture, and restricted permeability adversely affect

maintenance.
soil properties

Data relating to soil properties are collected during the

course of the soil survey. The data and the estimates of

soil and water features, listed in tables, are explained on the

following pages.

Soil properties are determined by field examination of the soils

and by laboratory index testing of some benchmark soils.

Established standard procedures are followed. During the

survey, many shallow borings are made and examined to

identify and classify the soils and to delineate them on the

soil maps. Samples are taken from some typical profiles and

tested in the laboratory to determine grain-size distribution,

plasticity, and compaction characteristics.

Estimates of soil properties are based on field

examinations, on laboratory tests of samples from the

survey area, and on laboratory tests of samples of similar soils

in nearby areas. Tests verify field observations, verify

properties that cannot be estimated accurately by field

observation, and help characterize key soils.

The estimates of soil properties shown in the tables

include the range of grain-size distribution and Atterberg limits,

the engineering classifications, and the physical and

chemical properties of the major layers of each soil.

Pertinent soil and water features also are given.

engineering index properties

Table 13 gives estimates of the engineering

classification and of the range of index properties for the

major layers of each soil in the survey area. Most soils

have layers of contrasting properties within the upper 5

or 6 feet.

Depth to the upper and lower boundaries of each layer

is indicated. The range in depth and information on other

properties of each layer are given for each soil series under

"Soil series and their morphology."

Texture is given in the standard terms used by the U.S.

Department of Agriculture. These terms are defined according to

percentages of sand, silt, and clay in the fraction of the soil

that is less than 2 millimeters in diameter. "Loam," for

example, is soil that is 7 to 27 percent clay, 28 to 50 percent

silt, and less than 52 percent sand. If a soil contains particles

coarser than sand, an appropriate modifier is added, for

example, "gravelly." Textural terms are defined in the

Glossary.

Classification of the soils is determined according to the

Unified soil classification system (2) and the system

adopted by the American Association of State Highway and

Transportation Officials (1).

The Unified system classifies soils according to properties

that affect their use as construction material (14). Soils are

classified according to grain-size distribution of the fraction

less than 3 inches in diameter and, according to plasticity

index, liquid limit, and organic matter content. Sandy and

gravelly soils are identified as GW, GP, GM, GC, SW, SP,

SM, and SC; silty and clayey soils as ML, CL, OL, MH, CH,

and OH; and highly organic soils as Pt. Soils exhibiting

engineering properties of two groups can have a dual

classification, for example, SP-SM.

The AASHTO system classifies soils according to those

properties that affect roadway construction and maintenance.

In this system, the fraction of a mineral soil that is less than 3

inches in diameter is classified in one of seven groups from

A-1 through A-7 on the basis of grain-size distribution, liquid

limit, and plasticity index. Soils in group A-1 are coarse

grained and low in content of fines (silt and clay). At the

other extreme, soils in group A-7 are fine grained. Highly

organic soils are classified in group A-8 on the basis of

visual inspection.

Rock fragments larger than 3 inches in diameter are

indicated as a percentage of the total soil on a dry-weight

basis. The percentages are. estimates determined mainly by

converting volume percentage in the field to weight

percentage.

Percentage (of soil particles) passing designated sieves is

the percentage of the soil fraction less than 3 inches in

diameter based on an oven-dry weight. The sieves,

numbers 4, 10, 40, and 200 (USA Standard Series),

have openings of 4.76, 2.00, 0.420, and 0.074

millimeters, respectively. Estimates are based on laboratory

tests of soils sampled in the survey area and in nearby

areas and on estimates made in the field.

Liquid limit and plasticity index (Atterberg limits) indicate the

plasticity characteristics of a soil. The estimates are based

on test data from the survey area or from nearby areas and

on field examination.

The estimates of grain-size distribution, liquid limit,

and plasticity index are rounded to the nearest 5 percent.

Thus, if the ranges of gradation and Atterberg limits extend a

marginal amount (1 or 2 percentage points) across

classification boundaries, the classification in the marginal

zone is omitted in the table.
physical and chemical properties

Table 14 shows estimates of some characteristics and

features that affect soil behavior. These estimates are given

for the major layers of each soil in the survey area. The

estimates are based on field observations and on test data for

these and similar soils.

Clay as a soil separate consists of mineral soil particles

that are less than 0.002 millimeter in diameter. In this table,

the estimated clay content of each major soil layer is given as

a percentage, by weight, of the soil material that is less than 2

millimeters in diameter.

The amount and kind of clay greatly affect the fertility and

physical condition of the soil. They determine the ability of

the soil to adsorb cations and to retain moisture. They

influence shrink-swell potential, permeability, and plasticity, the

ease of soil dispersion, and other soil properties. The amount

and kind of clay in a soil also affect tillage and earth-moving

operations.

Permeability refers to the ability of a soil to transmit water or

air. The estimates indicate the rate of downward movement of

water when the soil is saturated. They are based on soil

characteristics observed in the field, particularly structure,

porosity, and texture. Permeability is considered in the design

of soil drainage systems, septic tank absorption fields, and

construction where the rate of water movement under

saturated conditions affects behavior.

Available water capacity refers to the quantity of water that

the soil is capable of storing for use by plants. The capacity for

water storage is given in inches of water per inch of soil for

each major soil layer. The capacity varies, depending on soil

properties that affect the retention of water and the depth of

the root zone. The most important properties are the content of

organic matter, soil texture, bulk density, and soil structure.

Available water capacity is an important factor in the choice

of plants or crops to be grown and in the design and

management of irrigation systems. Available water capacity

is not an estimate of the quantity of water actually available

to plants at any given time.

Soil reaction is a measure of acidity or alkalinity and is

expressed as a range in pH values. The range in pH of each major

horizon is based on many field tests. For many soils, values

have been verified by laboratory analyses. Soil reaction is

important in selecting crops and other plants, in evaluating soil

amendments for fertility and stabilization, and in determining

the risk of corrosion.

Shrink-swell potential is the potential for volume change in

a soil with a loss or gain in moisture. Volume change occurs

mainly because of the interaction of clay minerals with

water and varies with the amount and type of clay minerals

in the soil. The size of the load on the soil and the

magnitude of the change in soil moisture content influence

the amount of swelling of soils in place. Laboratory

measurements of swelling of undisturbed clods were made for

many soils. For others,

swelling was estimated on the basis of the kind and amount

of clay minerals in the soil and on measurements of

similar soils.

If the shrink-swell potential is rated moderate to very

high, shrinking and swelling can cause damage to

buildings, roads, and other structures. Special design is

often needed.

Shrink-swell potential classes are based on the change in

length of an unconfined clod as moisture content is increased

from air-dry to field capacity. The change is based on the soil

fraction less than 2 millimeters in diameter. The classes are

low, a change of less than 3 percent; moderate, 3 to 6

percent; and high, more than 6 percent. Very high, greater

than 9 percent, is sometimes used.

Erosion factor K indicates the susceptibility of a soil to

sheet and rill erosion by water. Factor K is one of six factors used

in the Universal Soil Loss Equation (USLE) to predict the average

annual rate of soil loss by sheet and rill erosion in tons per acre

per year. The estimates are based primarily on percentage of

silt, sand, and organic matter (up to 4 percent) and on soil

structure and permeability. Values of K range from 0.05 to

0.69. The higher the value the more susceptible the soil is

to sheet and rill erosion by water.

Erosion factor T is an estimate of the maximum average

annual rate of soil erosion by wind or water that can occur without

affecting crop productivity over a sustained period. The rate is in

tons per acre per year.

Organic matter is the plant and animal residue in the

soil at various stages of decomposition.

In table 14, the estimated content of organic matter of the

plow layer is expressed as a percentage, by weight, of the soil

material that is less than 2 millimeters in diameter.

The content of organic matter of a soil can be maintained

or increased by returning crop residue to the soil. Organic

matter affects the available water capacity, infiltration rate,

and tilth. It is a source of nitrogen and other nutrients for

crops.

soil and water features

Tables 15 and 16 give estimates of various soil and water

features. The estimates are used in land use planning that

involves engineering considerations.

Hydrologic soil groups are used to estimate runoff from

precipitation. Soils not protected by vegetation are assigned to

one of four groups. They are grouped according to the

intake of water when the soils are thoroughly wet and

receive precipitation from long-duration storms.

The four hydrologic soil groups are:

Group A. Soils having a high infiltration rate (low runoff

potential) when thoroughly wet. These consist mainly of

deep, well drained to excessively drained sands or gravelly

sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when

thoroughly wet. These consist chiefly of moderately deep or

deep, moderately well drained or well drained soils that have

moderately fine texture to moderately coarse texture. These

soils have a moderate rate of water transmission.

Group C. Soils having a slow infiltration rate when thoroughly

wet. These consist chiefly of soils having a layer that

impedes the downward movement of water or soils of

moderately fine texture or fine texture. These soils have a

slow rate of water transmission.

Group D. Soils having a very slow infiltration rate (high

runoff potential) when thoroughly wet. These consist chiefly

of clays that have a high shrink-swell potential, soils that

have a permanent high water table, soils that have a claypan

or clay layer at or near the surface, and soils that are

shallow over nearly impervious material. These soils have a

very slow rate of water transmission.

Flooding, the temporary inundation of an area, is caused by

overflowing streams, by runoff from adjacent slopes, or by

tides. Water standing for short periods after rainfall or

snowmelt and water in swamps and marshes is not

considered flooding.

Table 15 gives the frequency and duration of flooding and

the time of year when flooding is most likely.

Frequency, duration, and probable dates of occurrence

are estimated. Frequency is expressed as none, rare,

common, occasional, and frequent. None means that

flooding is not probable; rare that it is unlikely but possible

under unusual weather conditions; common that it is likely

under normal conditions; occasional that it occurs on an

average of once or less in 2 years; and frequent that it occurs

on an average of more than once in 2 years. Duration is

expressed as very brief if less than 2 days, brief if 2 to 7

days, and long if more than 7 days. Probable dates are

expressed in months; November-May, for example, means

that flooding can occur during the period November through

May.

The information is based on evidence in the soil profile,

namely thin strata of gravel, sand, silt, or clay deposited by

floodwater; irregular decrease in organic matter content with

increasing depth; and absence of distinctive horizons that

form in soils that are not subject to flooding.

Also considered are local information about the extent and

levels of flooding and the relation of each soil on the landscape

to historic floods. Information on the extent of flooding based

on soil data is less specific than that provided by detailed

engineering surveys that delineate flood-prone areas at

specific flood frequency levels.

High water table (seasonal) is the highest level of a

saturated zone in the soil in most years. The depth to a

seasonal high water table applies to undrained soils. The

estimates are based mainly on the evidence of a saturated

zone, namely grayish colors or mottles in the soil. Indicated in

table 15 are the depth to the seasonal high water table; the

kind of water table-that is

perched, artesian, or apparent; and the months of the year that

the water table commonly is high. A water table that is

seasonally high for less than 1 month is not indicated in

table 15.

An apparent water table is a thick zone of free water in the

soil. It is indicated by the level at which water stands in an

uncased borehole after adequate time is allowed for

adjustment in the surrounding soil. An artesian water table is

under hydrostatic head, generally beneath an impermeable

layer. When this layer is penetrated, the water level rises in an

uncased borehole. A perched water table is water standing

above an unsaturated zone. In places an upper, or perched,

water table is separated from a lower one by a dry zone.

Only saturated zones within a depth of about 6 feet are

indicated. A plus sign preceding the range in depth indicates that

the water table is above the surface of the soil. The first

numeral in the range indicates how high the water rises above

the surface. The second numeral indicates the depth below

the surface.

Depth to bedrock is given if bedrock is within a depth of 5

feet. The depth is based on many soil borings and on

observations during soil mapping. The rock is specified as

either soft or hard. If the rock is soft or fractured,

excavations can be made with trenching machines,

backhoes, or small rippers. If the rock is hard or massive,

blasting or special equipment generally is needed for

excavations.

Cemented pans are cemented or indurated subsurface

layers within a depth of 5 feet. Such pans cause difficulty in

excavation. Pans are classified as thin or thick. A thin pan is less

than 3 inches thick if continuously indurated or less than 18

inches thick if discontinuous or fractured. Excavations can

be made by trenching machines, backhoes, or small rippers. A

thick pan is more than 3 inches thick if continuously indurated

or more than 18 inches thick if discontinuous or fractured. Such a

pan is so thick or massive that blasting or special equipment is

needed in excavation.

Some soils in this survey area are underlain by dense, compact

glacial till. These soils are identified in the detailed map unit

descriptions, general map unit descriptions, and series

descriptions as having dense layers of glacial till. In the

interpretation tables, however, they are identified as having a

cemented pan. For most soil interpretations, the dense glacial till is

the same as a cemented pan.

Subsidence is the settlement of organic soils or of

saturated mineral soils of very low density. Subsidence

results from either desiccation and shrinkage or oxidation of

organic material, or both, following drainage. Subsidence

takes place gradually, usually over a period of several

years. Table 16 shows the expected initial subsidence,

which usually is a result of drainage, and annual

subsidence, which usually is a result of oxidation.

Not shown in the table is subsidence caused by an

imposed surface load or by the withdrawal of ground water

throughout an extensive area as a result of lowering the

water table.
Potential frost action is the likelihood of upward or lateral

expansion of the soil caused by the formation of segregated

ice lenses (frost heave) and the subsequent collapse of the soil

and loss of strength on thawing. Frost action occurs when

moisture moves into the freezing zone of the soil.

Temperature, texture, density, permeability, content of organic

matter, and depth to the water table are the most important

factors considered in evaluating the potential for frost action.

It is assumed that the soil is not insulated by vegetation or

snow and is not artificially drained. Silty and highly

structured clayey soils that have a high water table in winter

are most susceptible to frost action. Well drained, very

gravelly, or very sandy soils are the least susceptible.

Frost heave and low soil strength during thawing cause damage

mainly to pavements and other rigid structures.

Risk of corrosion pertains to potential soil-induced

electrochemical or chemical action that dissolves or

weakens uncoated steel or concrete. The rate of

corrosion of uncoated steel is related to such factors as soil

moisture, particle-size distribution, acidity, and electrical

conductivity of the soil. The rate of corrosion of concrete is

based mainly on the sulfate and sodium content, texture,

moisture content, and acidity of the soil. Special site

examination and design may be needed if the combination

of factors creates a severe corrosion environment. The

steel in installations that intersect soil boundaries or soil

layers is more susceptible to corrosion than steel in

installations that are entirely within one kind of soil or within

one soil layer.

For uncoated steel, the risk of corrosion, expressed as

low, moderate, or high, is based on soil drainage class, total

acidity, electrical resistivity near field capacity, and electrical

conductivity of the saturation extract.

For concrete, the risk of corrosion is also expressed as

low, moderate, or high. It is based on soil texture, acidity,

and amount of sulfates in the saturation extract.
classification of the soils

The system of soil classification used by the National

Cooperative Soil Survey has six categories (19). Beginning with

the broadest, these categories are the order, suborder,

great group, subgroup, family, and series. Classification is

based on soil properties observed in the field or inferred from

those observations or from laboratory measurements. In

table 17, the soils of the survey area are classified

according to the system (10). The categories are defined in

the following paragraphs.

ORDER. Ten soil orders are recognized. The

differences among orders reflect the dominant soilforming processes and the degree of soil formation.

Each order is identified by a word ending in sol. An

example is Entisol.

SUBORDER. Each order is divided into suborders primarily on

the basis of properties that influence soil genesis and are

important to plant growth or properties that reflect the most

important variables within the orders. The last syllable in

the name of a suborder indicates the order. An example is

Aquent (Aqu, meaning water, plus ent, from Entisol).

GREAT GROUP. Each suborder is divided into great groups on

the basis of close similarities in kind, arrangement, and

degree of development of pedogenic horizons; soil moisture

and temperature regimes; and base status. Each great

group is identified by the name of a suborder and by a

prefix that indicates a property of the soil. An example is

Fluvaquents (Fluv, meaning flood plain, plus aquent, the

suborder of the Entisols that have an aquic moisture regime).

SUBGROUP. Each great group has a typic subgroup. Other

subgroups are intergrades or extragrades. The typic is the

central concept of the great group; it is not necessarily the

most extensive. Intergrades are transitions to other orders,

suborders, or great groups. Extragrades have some properties

that are not representative of the great group but do not

indicate transitions to any other known kind of soil. Each

subgroup is identified by one or more adjectives preceding

the name of the great group. The adjective Aeric

identifies the subgroup that typifies the great group. An

example is Aeric Fluvaquents.

FAMILY. Families are established within a subgroup on the

basis of physical and chemical properties and other

characteristics that affect management. Mostly the

properties are those of horizons below plow depth where

there is much biological activity. Among the properties

and characteristics considered are particle-size class,

mineral content, temperature regime, depth of the root

zone, consistence, moisture equivalent, slope, and permanent

cracks. A family name consists of the name of a subgroup

preceded by terms that indicate soil properties. An example

is fine-silty, mixed, nonacid, mesic Aeric Fluvaquents.

SERIES. The series consists of soils that have similar

horizons in their profile. The horizons are similar in color,

texture, structure, reaction, consistence, mineral and

chemical composition, and arrangement in the profile. The

texture of the surface layer or of the substratum can differ

within a series.

soil series and their morphology

In this section, each soil series recognized in the survey

area is described. The descriptions are arranged in alphabetic

order.

Characteristics of the soil and the material in which it

formed are identified for each series. The soil is compared

with similar soils and with nearby soils of other series. A

pedon, a small three-dimensional area of soil, that is

typical of the series in the survey area is described. The

detailed description of each soil horizon follows standards in

the Soil Survey Manual (17). Many technical terms used in

the descriptions are defined in Soil Taxonomy (19). Unless

otherwise stated, colors in the descriptions are for moist soil.

Following the pedon description is the range of important

characteristics of the soils in the series.

The map units of each soil series are described in the

section "Detailed soil map units."

Alderwood series

The Alderwood series consists of moderately deep,

moderately well drained soils on till plains. These soils

formed in glacial till. Slope is 2 to 70 percent. Elevation is

50 to 550 feet. The average annual precipitation is about 40

inches, the average annual air temperature is about 50

degrees F, and the average frost-free season is 170 to 190

days.

Typical pedon of Alderwood gravelly sandy loam, 2 to 8

percent slopes, 200 feet south and 400 feet east of the

center of sec. 28, T. 27 N., R. 5 E.
Ap-0 to 7 inches; very dark grayish brown (10YR 3/2)

gravelly sandy loam, brown (10YR 5/3) dry; moderate fine

granular structure; slightly hard, very friable, slightly sticky

and slightly plastic; many fine roots; few fine interstitial

pores; 20 percent pebbles; slightly acid; abrupt smooth

boundary.

B21-7 to 21 inches; dark yellowish brown (10YR 4/4) very gravelly

sandy loam, yellowish brown (10YR 5/4) dry; weak

medium subangular blocky structure; slightly hard,

very friable, nonsticky and nonplastic; many fine roots;

many fine tubular and interstitial pores; 40 percent pebbles;

slightly acid; diffuse smooth boundary.

B22-21 to 30 inches; dark brown (10YR 4/3) very gravelly

sandy loam; pale brown (10YR 6/3) dry; weak medium

subangular blocky structure; slightly hard, very friable,

nonsticky and nonplastic; common fine roots; few very

fine tubular pores; 40 percent pebbles; slightly acid; clear

wavy boundary.

B3-30 to 35 inches; 50 percent olive brown (2.5Y 4/4) very

gravelly sandy loam, light yellowish brown (2.5Y 6/4) dry, and

50 percent dark grayish brown (2.5Y 4/2) fragments of

consolidated lodgment till with strong brown (7.5YR

5/6) coatings on fragments, tight brownish gray (2.5Y

6/2) and reddish yellow (7.5YR 6/6) dry; massive;

slightly hard, very friable, nonsticky and nonplastic; few

fine roots; common fine tubular and interstitial pores; 45

percent pebbles; medium acid; abrupt wavy boundary.

lIC1sim-35 to 43 inches; dark grayish brown (2.5Y 4/2) duripan,

light brownish gray (2.5Y 6/2) dry; dark yellowish

brown (10YR 4/4), reddish brown (5YR 4/4), yellowish

red (5YR 4/8), and strong brown (7.5YR 5/6) coatings

on till fragments; massive; weakly cemented; extremely

hard, extremely firm; few fine roots; few fine tubular

pores; 40 percent pebbles; medium acid; abrupt

irregular boundary.

IIC2-43 to 60 inches; grayish brown (2.5Y 5/2) compact

glacial till that breaks to gravelly sandy loam, light gray

(2.5Y 7/2) dry; massive; extremely hard, extremely

firm, nonsticky and nonplastic, 20 percent pebbles;

medium acid.

The duripan is at a depth of 20 to 40 inches. The

mean annual soil temperature at a depth of 20 inches

ranges from 48 to 52 degrees F. The control section

averages 35 to 50 percent rock fragments. It is medium

acid or slightly acid.

The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 when

moist and 4 or 5 when dry, and chroma of 2 to 4 when

moist or dry.

The B horizon has hue of 10YR, 7.5YR, or 2.5YR, and it

has value and chroma of 3 to 6 when moist or dry. It is very

gravelly loam or very gravelly sandy loam.

The lIC1sim horizon has hue of 10YR or 2.5Y, value of 5 to 7

when dry, and chroma of 2 to 4 when dry. It is very gravelly

sandy loam, very gravelly loamy sand, gravelly sandy loam, or

gravelly loamy sand.

Bellingham series

The Bellingham series consists of very deep, poorly

drained soils in depressional areas. These soils formed in

alluvium and lake sediment. Slope is 0 to 3 percent.

Elevation is 50 to 800 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 160 to 180 days.

Typical pedon of Bellingham silty clay loam about

1,150 feet south and 80 feet west of the northeast

corner of sec. 27, T. 30 N., R. 5 E.

Ap-0 to 9 inches; very dark gray (10YR 3/1) silty clay

loam, grayish brown (10YR 5/2) dry; moderate fine and

medium subangular blocky structure; hard, firm, sticky and

plastic; common very fine and fine roots; medium acid;

clear smooth boundary.

B21g-9 to 21 inches; gray (5Y 5/1, 6/1) silty clay, light

gray (2.5Y 7/0) dry; few fine and medium distinct strong

brown (7.5YR 5/6) mottles and few fine distinct yellowish

brown (10YR 5/6) mottles; few large distinct dusky red

(2.5YR 3/2) organic stains; weak medium prismatic

structure parting to moderate medium subangular blocky;

very hard, very firm, sticky and very plastic; few fine

roots; few fine and medium vertical pores; continuous

pressure faces on peds; slightly acid; gradual smooth

boundary.

B22g-21 to 60 inches; olive (5Y 5/6) and gray (5Y 6/1)

silty clay, light gray (5Y 7/1) dry; few fine and medium

distinct strong brown (7.5YR 5/6) mottles and common

fine and medium distinct yellowish brown (10YR 5/6)

mottles; few large distinct dusky red (2.5YR 3/2)

organic stains; moderate medium subangular blocky

structure; very hard, very firm, sticky and very plastic; very

few fine roots; few very fine vertical pores; continuous

pressure faces on peds; neutral.

The estimated mean annual soil temperature at a depth

of 20 inches is 48 to 52 degrees F. The control section

averages 40 to 60 percent clay.

The A horizon has value of 2 to 5 when moist or dry and

chroma of 1 to 3.

The B horizon has hue of 5Y, 5GY, or 2.5Y, value of 5 to

7 when moist and 6 or 7 when dry, and chroma of 1 to 6.

Bellingham Variant

The Bellingham Variant consists of very deep, poorly

drained soils in drainageways. These soils formed in

alluvium. Slope is 0 to 3 percent. Elevation is 650 to 1,800

feet. The average annual precipitation is about 60 inches,

the average annual air temperature is about 44 degrees F,

and the average frost-free season is 130 to 150 days.
Typical pedon of Bellingham Variant mucky silty clay

loam about 2,250 feet west and 1,400 feet south of the

northeast corner of sec. 27, T. 30 N., R. 7 E.

O1-2 inches to 0; dead grass, leaves, and roots.

A1-0 to 6 inches; very dark grayish brown (10YR 3/2)

mucky silty clay loam, grayish brown (10YR 5/2) dry;

moderate medium subangular blocky structure; slightly

hard, friable, slightly sticky and slightly plastic; many very

fine and fine roots; strongly acid; clear smooth boundary.

AC-6 to 12 inches; dark grayish brown (2.5Y 4/2) silty clay

loam, light brownish gray (2.5Y 6/2) dry; few medium distinct

yellowish brown (10YR 5/8) mottles; weak medium

subangular blocky structure; hard, friable, slightly sticky

and slightly plastic; common very fine roots; strongly

acid; clear smooth boundary.

C1g-12 to 24 inches; gray (5Y 5/1) silty clay loam, light

gray (2.5Y 7/0) dry; common medium distinct yellowish

brown (10YR 5/8) mottles; massive; very hard, firm, sticky

and plastic; few very fine and fine roots; very strongly

acid; clear smooth boundary.

C2g-24 to 36 inches; gray (5Y 6/1) silty clay loam, light gray (5Y

7/1) dry; common medium distinct yellowish brown (10YR

5/8) mottles; massive; very hard, firm, sticky and plastic;

few very fine roots; very strongly acid; clear smooth

boundary.

C3g-36 to 42 inches; greenish gray (5GY 6/1) silty clay,

greenish gray (5GY 5/1) dry; massive; very hard, firm,

sticky and plastic; few very fine roots; very strongly acid;

abrupt smooth boundary.

C4g-42 to 60 inches; greenish gray (5GY 6/1) stratified loamy

fine sand and silty clay loam, greenish gray (5GY 5/1)

dry; massive; slightly hard, friable, slightly sticky and

slightly plastic; very strongly acid.

The mean annual soil temperature at a depth of 20

inches ranges from 44 to 47 degrees F. The control

section averages 35 to 45 percent clay.

The A horizon has hue of 10YR or 7.5YR, value of 2 or 3

when moist and 3 to 5 when dry, and chroma of 1 or 2

when moist or dry. The AC horizon has hue of 7.5YR to

2.5Y, value of 3 or 4 when moist and 5 or 6 when dry, and

chroma of 2 or 3 when moist or dry.

The C horizon has hue of 2.5Y or 5Y, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 0 to 2

when moist or dry. The Cg horizon has hue of 5GY or 5Y,

value of 5 or 6, and chroma of 1 or 2.

Cathcart series

The Cathcart series consists of very deep, well drained

soils on foothills and mountain foot slopes. These soils

formed in glacial drift derived from sandstone and siltstone

and in volcanic ash. Slope is 3 to 50 percent. Elevation is

50 to 1,000 feet. The average annual precipitation is about

45 inches, the average annual air

temperature is about 50 degrees F, and the average

frost-free season is 165 to 185 days.

Typical pedon of Cathcart loam, 3 to 15 percent

slopes, 1,000 feet west and 1,500 feet south of the

northeast corner of sec. 12, T. 32 N., R. 4 E.

Ap-0 to 8 inches; very dark grayish brown (10YR 3/2)

loam, grayish brown (10YR 5/2) dry; weak fine granular

structure; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; common very fine and fine roots;

common fine tubular pores; 5 percent granitic pebbles 2

millimeters to 3/4 inch in diameter; strongly acid; abrupt

smooth boundary.

B21-8 to 17 inches; dark brown (10YR 4/3) loam, pale brown

(10YR 6/3) dry; few fine distinct yellowish red (5YR 4/6)

mottles, strong brown (7.5YR 5/6) dry; weak medium

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; few very fine

and fine roots; common fine tubular and interstitial pores;

10 percent granitic pebbles 2 millimeters to 3/4 inch in

diameter, and 5 percent angular soft sandstone

fragments 1 inch to 3 inches in diameter; 5 percent iron

concretions 2 to 4 millimeters in diameter; strongly acid;

clear smooth boundary.

B22-17 to 25 inches; yellowish brown (10YR 5/4) loam, very

pale brown (10YR 7/4) dry; weak medium subangular

blocky structure; slightly hard, friable, slightly sticky and

slightly plastic; weakly smeary; few very fine and fine

roots; few fine tubular pores and common fine interstitial

pores; 10 percent granitic pebbles 2 millimeters to 3/4

inch in diameter; 5 percent iron concretions 2 to 4

millimeters in diameter; strongly acid; abrupt smooth

boundary.

B3-25 to 35 inches; dark brown (10YR 4/3) sandy loam,

very pale brown (10YR 7/4) dry; many fine prominent

dark reddish brown (2.5YR 3/4) mottles, strong brown

(7.5YR 5/6) dry; massive; hard, firm, slightly sticky and

slightly plastic; weakly smeary; common fine interstitial

pores; 35 percent soft angular sandstone fragments 3/4 inch

to 3 inches in diameter; slightly acid; abrupt wavy

boundary.

C1-35 to 53 inches; olive (5Y 5/3) loam, light gray (5Y 7/2)

dry; many medium distinct dark reddish brown (2.5YR

3/4) mottles, reddish brown (5YR 4/4) dry; massive;

slightly hard, friable, slightly sticky and slightly plastic;

weakly smeary; few fine interstitial pores; 20 percent

soft angular sandstone fragments 3/4 inch to 3 inches in

diameter; slightly acid; clear wavy boundary.

C2-53 to 60 inches; olive (5Y 5/3) loam, light gray (5Y 7/2)

dry; many medium prominent dark reddish brown (2.5YR

3/4) mottles, reddish brown (5YR 4/4) dry; massive; hard,

friable, slightly sticky and slightly plastic; weakly smeary;

few fine and medium interstitial pores; 70 percent soft

angular sandstone fragments 3/4 inch to 3 inches in

diameter; slightly acid.
The mean annual soil temperature ranges from 40 to 52

degrees F. The profile ranges from very strongly acid to slightly

acid. The control section averages 0 to 10 percent rock

fragments.

The A horizon has hue of 10YR to 7.5YR and value of

2 to 4 when moist and 3 to 6 when dry. The B horizon has

hue of 10YR to 2.5YR, value of 3 to 5 when moist and 3 to 7

when dry, and chroma of 2 to 4 when moist or dry. It is

sandy loam, loam, or silt loam. The C horizon has hue of

10YR to 5Y, value of 3 to 5 when moist and 3 to 7 when dry,

and chroma of 2 to 5 when moist or dry. It is loam or clay

loam.

Custer series

The Custer series consists of very deep, poorly drained

soils in basins on outwash plains. These soils formed in

glacial outwash. Slope is 0 to 2 percent. Elevation ranges

from near sea level to 150 feet. The average annual

precipitation is about 40 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 150 to 200 days.

Typical pedon of Custer fine sandy loam, 2,250 feet west and

1,500 feet north of the southeast corner of sec. 5, T. 30 N.,

R. 5 E. (fig. 4).

Ap-0 to 9 inches; very dark grayish brown (10YR 3/2) fine

sandy loam, light brownish gray (10YR 6/2) dry; weak

fine granular structure; slightly hard, very friable, nonsticky

and nonplastic; many fine and medium roots; common fine

tubular pores; medium acid; abrupt smooth boundary.

B21ircm-9 to 16 inches; 60 percent dark reddish brown (5YR 3/4

and 3/3) and dark brown (10YR 3/3) ortstein

concretions 1 /2 inch to 2 inches in diameter, yellowish

red (5YR 5/8 and 5/6) dry; 40 percent loamy fine sand

that is olive (5Y 5/3) and light yellowish brown (10YR

6/4) when dry; massive; friable to slightly hard in matrix

and very hard to extremely hard ortstein forming a

discontinuous iron-cemented hardpan; nonsticky and

nonplastic; few fine roots; few fine tubular pores;

strongly acid; clear irregular boundary.

B22ir-16 to 35 inches; gray (5Y 5/1) and olive (5Y 5/3)

medium sand, light brownish gray (2.5Y 6/2) dry;

about 20 percent dark reddish brown (5YR 3/4) and

dark brown (7.5YR 3/4) ortstein concretions 1 /8 inch to

2 inches in diameter; common fine and medium distinct

dark reddish brown (5YR 3/4) and dark brown (7.5YR

3/4) mottles, light olive brown (2.5Y 5/6 and 5/4) dry;

soft to slightly hard matrix and very hard to extremely

hard ortstein forming a discontinuous iron-cemented

hardpan; nonsticky and nonplastic; very few fine roots;

common very fine tubular pores; strongly acid; clear

wavy boundary.

C1g-35 to 49 inches; gray (N 5/0) fine and medium

sand, olive gray and light olive gray (5Y 5/2 and

6/2) dry; common fine faint grayish brown (2.5Y

Figure 4.-Typical profile of Custer fine sandy loam.

5/2) mottles; single grain; loose; many very fine

interstitial pores; medium acid; abrupt wavy

boundary.

IIC2g-49 to 60 inches; mottled dark gray (5Y 4/1) and

dark brown (7.5YR 4/4) gravelly coarse sand, gray (5Y

6/1), light olive gray (5Y 6/2) and light olive brown

(2.5Y 5/4) dry; single grain; loose; many very fine

interstitial pores; 25 percent pebbles 2 millimeters to 3/4

inch in diameter; medium acid.

The estimated mean annual soil temperature is 48 to 52

degrees F. The control section averages 0 to 15 percent

rock fragments.

The A horizon has value of 2 or 3 when moist and 3 to 6
moist. Some pedons have an A2 horizon of loamy sand

or fine sandy loam 1/2 inch to 2 inches thick.

The B2 horizon has hue of 5Y, 2.5Y, or 10YR in the matrix and

10YR to 5YR in the ortstein concretions and mottles. It has

value of 3 to 5 when moist and 4 to 6 when dry, and it has

chroma of 3 to 8 when dry and 3 to 6 when moist. The B2

horizon is loamy fine sand to sand. The ortstein occurs as

rounded concretions, irregularly shaped accretions, nearly

continuous bands, or slaglike, irregularly shaped plates

that form a discontinuous, iron-cemented hardpan.

The C horizon has hue of 2.5Y, 5Y, or 10YR, value of 4 to 5

when moist and 5 to 7 when dry, and chroma of 0 to 4

when moist or dry. It is coarse sand to fine sand and is

gravelly in some pedons.

Elwell series

The Elwell series consists of moderately deep,

moderately well drained soils on mountainsides and ridgetops.

These soils formed in glacial till and volcanic ash. Slope is

3 to 90 percent. Elevation is 800 to 1,800 feet. The average

annual precipitation is about 70 inches, the average annual air

temperature is about 45 degrees F, and the average frostfree season is 130 to 150 days.

Typical pedon of Elwell silt loam, 3 to 30 percent slopes,

about 7 miles northeast of Granite Falls; 2,640 feet north

and 1,570 feet west of the southeast corner of sec. 27, T. 31

N., R. 7 E.

O1-2 inches to 1 inch; leaves, needles, and twigs.

O2-1 inch to 0; decomposed mat of leaves, needles,

and twigs.

A1-0 to 2 inches; black (10YR 2/1) silt loam, very dark

brown (10YR 2/2) dry; moderate fine granular structure;

slightly hard, friable, slightly sticky and slightly plastic; weakly

smeary; many fine, medium, and coarse roots; many fine

tubular pores; extremely acid; abrupt smooth boundary.

B21ir-2 to 8 inches; strong brown (7.5YR 5/6) silt loam, reddish

yellow (7.5YR 6/6) dry; moderate medium

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; many fine,

medium, and coarse roots; few fine tubular pores; 5

percent pebbles and 5 percent iron concretions; strongly

acid; gradual wavy boundary.

B22ir-8 to 14 inches; brown (7.5YR 5/4) silt loam, light

brown (7.5YR 6/4) dry; moderate medium subangular

blocky structure; slightly hard, friable, slightly sticky and

slightly plastic; weakly smeary; common medium and

coarse roots; few fine tubular pores; 5 percent pebbles

and 5 percent concretions; strongly acid; gradual wavy

boundary.

B23-14 to 23 inches; yellowish brown (10YR 5/6) silt loam,

yellow (10YR 7/6) dry; few fine faint brownish yellow

(10YR 6/6) mottles, yellow (10YR 8/6) dry; weak

medium subangular blocky structure; slightly

hard, friable, slightly sticky and slightly plastic;

weakly smeary; few fine, medium, and coarse roots;

few fine tubular pores; 10 percent pebbles; strongly

acid; abrupt smooth boundary.

C1-23 to 27 inches; pale olive (5Y 6/4) gravelly fine

sandy loam, pale yellow (5Y 7/4) dry; many large

distinct dark yellowish brown (10YR 4/4) mottles, light

yellowish brown (10YR 6/4) dry; weak medium platy

structure; hard, firm, slightly sticky and slightly plastic;

weakly smeary; few fine tubular pores; 20 percent

pebbles; strongly acid; abrupt smooth boundary.

lIC2sim-27 inches; weakly cemented duripan that breaks

down to olive (5Y 5/3) gravelly sandy loam, pale olive

(5Y 6/3) dry; massive; hard, very firm, nonsticky and

nonplastic; 20 percent pebbles; medium acid.

The mean annual soil temperature at a depth of 20 inches

is 45 to 47 degrees F. Depth to the duripan ranges from 20

to 40 inches. The control section is 5 to 30 percent coarse

fragments.

The A1 horizon has hue of 10YR or 7.5YR, and it has

value of 2 or 3 when moist and 2 to 4 when dry. Some

pedons have an A2 horizon that has hue of 10YR or 7.5YR,

value of 4 or 5 when moist and 6 when dry, and chroma of

1 to 3 when moist or dry.

The B21 it horizon has hue of 10YR, 7.5YR, or 5YR,

value of 3 to 6 when moist and 4 to 7 when dry, and

chroma of 2 to 6 when moist or dry. It is loam or silt

loam. The B23 horizon has hue of 2.5Y, 5Y, or 10YR,

value of 3 to 6 when moist and 5 to 8 when dry, and

chroma of 4 to 6 when moist or dry.

The C horizon has hue of 2.5Y or 5Y, value of 4 to 6 when

moist and 5 to 8 when dry, and chroma of 2 to 4 when

moist or dry. It is gravelly loamy sand, gravelly fine sandy

loam, gravelly sandy loam, or gravelly loam.

Everett series

The Everett series consists of very deep, somewhat

excessively drained soils on terraces and outwash plains.

These soils formed in glacial outwash. Slope is 0 to 70

percent. Elevation ranges from near sea level to 500 feet.

The average annual precipitation is about 40 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free season is 170 to 190 days.

Typical pedon of Everett gravelly sandy loam, 0 to 8

percent slopes, 2,550 feet east and 600 feet north from the

southwest corner of sec. 14, T. 28 N., R. 6 E.

A1-0 to 1 inch; very dark grayish brown (10YR 3/2)

gravelly loam, pale brown (10YR 6/3) dry; moderate

fine granular structure; slightly hard, very friable,

nonsticky and slightly plastic; many fine and medium

roots; many fine interstitial pores; 20 percent pebbles;

medium acid; abrupt smooth boundary.
B2ir-1 inch to 18 inches; dark brown (7.5YR 3/2) very

gravelly sandy loam, yellowish brown (10YR 5/4) dry;

weak fine granular structure; slightly hard, very friable,

nonsticky and slightly plastic; many fine and medium

roots and few coarse roots; many fine interstitial pores

and few fine tubular pores; 35 percent pebbles; slightly

acid; abrupt smooth boundary.

C1-18 to 33 inches; dark brown (7.5YR 4/2) very gravelly

loamy sand, reddish yellow (7.5YR 6/6) dry; common

medium and large faint dark brown (7.5YR 4/4) mottles;

massive; soft, very friable, nonsticky and nonplastic;

many fine and medium pores and common fine interstitial

pores; 40 percent pebbles; slightly acid; clear smooth

boundary.

C2-33 to 60 inches; dark brown (7.5YR 4/4) and pale yellow (2.5Y

7/4) extremely gravelly sand, light brownish gray (2.5Y

6/2), brown (7.5YR 5/2), and light brown (7.5YR 6/4) dry;

single grain; loose; very few fine roots; many fine interstitial

pores; 65 percent pebbles; slightly acid.

The estimated mean annual soil temperature at a depth of

20 inches is 50 to. 54 degrees F. The solum is 15 to 35 inches

thick. The control section averages 35 to 70 percent coarse

fragments.

The A horizon has hue of 10YR to 7.5YR, value of 2 to 4

when moist and 4 to 6 when dry, and chroma of 1 to 3. The

B horizon has hue of 10YR or 7.5YR, and it has value of 2

to 4 when moist and 4 to 6 when dry. The C horizon has

hue of 7.5YR to 2.5Y, value of 2 to 4 when moist and 5 to 7

when dry, and chroma of 1 to 6. It ranges from extremely

gravelly coarse sand to very gravelly loamy sand.

Getchell series

The Getchell series consists of moderately deep,

moderately well drained soils on mountainsides and ridgetops.

These soils formed in glacial till and volcanic ash. Slope is 3

to 90 percent. Elevation is 1,800 to 2,600 feet. The average

annual precipitation is about 90 inches, the average annual

air temperature is about 43 degrees F, and the average frostfree season is 105 to 125 days.

Typical pedon of Getchell silt loam, 3 to 30 percent slopes,

about 7 miles northeast of Granite Falls, 1,250 feet west

and 250 feet north of the southeast corner of sec. 15, T. 31

N., R. 7 E.

O1-1 1/2 inches to 1 inch; leaves, needles, and twigs.

O2-1 inch to 0; decomposed mat of needles, twigs, and

leaves.

A1-0 to 2 inches; black (10YR 2/1) and very dark brown

(10YR 2/2) silt loam, very dark brown (10YR 2/2) dry;

moderate fine granular structure; slightly hard, very

friable, slightly sticky and slightly plastic; many fine,

medium, and coarse roots; many fine

interstitial pores; 10 percent rounded pebbles;

extremely acid; abrupt smooth boundary.

B21hir-2 to 4 inches; yellowish red (5YR 4/6) silt loam, strong

brown (7.5YR 5/6) dry; dark reddish brown (5YR 3/2)

coatings on peds, dark reddish brown (5YR 3/4) dry;

moderate medium subangular blocky structure; slightly

hard, very friable, slightly sticky and slightly plastic; weakly

smeary; common fine, medium, and coarse roots; few fine

tubular pores; 10 percent pebbles and 5 percent iron

concretions; strongly acid; abrupt wavy boundary.

B22hir-4 to 10 inches; strong brown (7.5YR 5/6) silt loam,

yellowish brown (10YR 5/8) dry; reddish brown (5YR

4/4) coatings on peds, yellowish brown (10YR 5/4) dry;

weak medium subangular blocky structure; slightly hard,

very friable, slightly sticky and slightly plastic; weakly

smeary; common medium and coarse roots; few fine tubular

pores; 10 percent pebbles and 2 percent cobbles; strongly

acid; gradual wavy boundary.

B31-10 to 20 inches; strong brown (7.5YR 5/8) silt loam, light

yellowish brown (10YR 6/4) dry; dark brown (7.5YR 4/4)

coatings in cracks, dark yellowish brown (10YR 4/4) dry;

massive; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; few medium roots; few fine

tubular pores; 10 percent pebbles and 2 percent cobbles;

strongly acid; clear wavy boundary.

B32-20 to 29 inches; light olive brown (2.5Y 5/4) silt loam, very

pale brown (10YR 7/3 and 7/4) dry; many fine and

medium distinct dark reddish brown (5YR 3/3), strong

brown (7.5YR 5/8), and dark brown (7.5YR 4/4)

coatings in old root channels, strong brown (7.5YR 5/6)

and dark brown (7.5YR 4/4) dry; massive; slightly hard,

friable, slightly sticky and slightly plastic; weakly smeary; few

medium roots; common fine tubular pores; 10 percent

pebbles and 2 percent cobbles; strongly acid; clear smooth

boundary.

B33-29 to 36 inches; dark brown (7.5YR 3/2 and 3/4) silt loam,

yellowish brown (10YR 5/6) dry; common fine faint

strong brown (7.5YR 5/6) mottles, dark yellowish brown

(10YR 4/4) dry; massive; slightly hard, friable, slightly sticky

and slightly plastic; few medium roots; few fine tubular pores;

10 percent pebbles and 2 percent cobbles; strongly acid;

abrupt smooth boundary.

llCr-36 to 75 inches; olive (5Y 5/3) and pale olive (5Y 6/3) dense

glacial till that breaks to sandy loam, light gray (5Y 7/2)

and light olive gray (5Y 6/2)dry; extremely hard, very firm;

few fine tubular pores; 10 percent pebbles and 2 percent

cobbles inbedded in pan; few fine tubular pores; strongly

acid.

The mean annual soil temperature at a depth of 20

inches is 43 to 45 degrees F. Depth to the IICr horizon

ranges from 20 to 40 inches. The control section

averages 5 to 15 percent coarse fragments.
The A1 horizon has value of 2 or 3 when dry.

The B2ir horizon has hue of 10YR to 5YR, value of 3 to 6 when

moist and 4 to 7 when dry, and chroma of 2 to 8 when

moist or dry. It is loam or silt loam. The B3 horizon has

hue of 2.5Y, 5Y, 7.5YR, or 10YR, value of 3 to 6 when

moist and 5 to 7 when dry, and chroma of 2 to 8 when

moist or dry.

The IICr horizon has hue of 2.5Y or 5Y, value of 4 to 6

when moist and 5 to 8 when dry, and chroma of 2 to 4 when

moist or dry. It is dense glacial till that breaks to sandy loam or

loam.

Greenwater series

The Greenwater series consists of very deep, somewhat

excessively drained soils on terraces. These soils formed in

alluvium. Slope is 0 to 3 percent. Elevation is 400 to 600

feet. The average annual precipitation is about 60 inches, the

average annual air temperature is about 49 degrees F, and

the average frost-free season is 140 to 160 days.

Typical pedon of Greenwater loamy sand, 1,300 feet

west and 1,200 feet north of the southeast corner of sec.

11, T. 32 N., R. 9 E.

O1-1 inch to 0; matted roots, leaves, needles, and

twigs.

A2-0 to 2 inches; dark brown (7.5YR 3/2) loamy sand,

gray (7.5YR 5/0) dry; massive; soft, very friable,

nonsticky and nonplastic; common very fine, fine,

medium, and coarse roots; medium acid; clear smooth

boundary.

B21ir-2 to 9 inches;. dark brown (10YR 4/3) loamy sand, grayish

brown (10YR 5/2) dry; dark brown (7.5YR 4/4) stains

over 40 percent of sand grains; massive; soft, very

friable, nonsticky and nonplastic; common very fine, fine,

medium and coarse roots; 1 to 4 percent fine pumice;

medium acid; abrupt smooth boundary.

B22ir-9 to 21 inches; dark brown (10YR 4/3) loamy sand, brown

(10YR 5/3) dry; dark reddish brown (5YR 3/4) stains

over 40 percent of sand grains; massive; soft, very

friable, nonsticky and nonplastic; common very fine, fine,

medium, and coarse roots; 5 to 10 percent fine

pumice; medium acid; abrupt smooth boundary.

C1-21 to 40 inches; dark gray (2.5Y 4/1) sand, gray (2.5Y

5/1) dry; many large distinct weak red (2.5YR 4/2)

mottles; single grain; loose; common very fine roots and

few fine, medium, and coarse roots; 1 to 4 percent

pumice; less than 5 percent pebbles; slightly acid; clear

wavy boundary.

C2-40 to 60 inches; dark gray (2.5Y 4/1) sand, gray

(2.5Y 5/1) dry; single grain; loose; 1 to 4 percent

fine pumice; less than 5 percent pebbles; slightly

acid.

The mean annual soil temperature is 48 to 51 degrees F.

The profile usually is moist, but it is dry throughout for

more than 60 consecutive days each year. The profile is

medium acid to slightly acid. The control section is less than

15 percent coarse fragments. The profile averages 5 to 25

volcanic ash, cinders, and pumice.

The A horizon has value of 2 or 3 when moist, and it has

chroma of 2 or 3 when moist.

The Bir horizon has value of 3 or 4 when moist and 5 or

6 when dry, and it has chroma of 2 to 4 when moist or dry.

It is loamy sand or sand.

The C horizon has hue of 10YR or 2.5Y, value of 3 to 5,

and chroma of 1 to 4. Sand stratified with thin layers of

sandy loam and silt loam is at a depth of more than 40

inches.

Hartnit series

The Hartnit series consists of moderately deep,

moderately well drained soils on mountainsides and

ridgetops. These soils formed in glacial till, volcanic ash,

and material weathered from andesite, argillite, and basalt.

Slope is 3 to 90 percent. Elevation is 2,600 to 3,600 feet.

The average annual precipitation is about 90 inches, the

average annual air temperature is about 41 degrees F,

and the average frost-free season is 90 to 100 days.

Typical pedon of Hartnit gravelly silt loam, 65 to 90

percent slopes, 1,100 feet west and 1,800 feet north of the

southeast corner of sec. 17, T. 28 N., R. 9 E.

O1-7 to 6 inches; leaves, needles, and twigs.

O2-6 inches to 0; decomposed mat of needles, twigs,

and leaves.

A1-0 to 4 inches; black (5YR 2/1) gravelly silt loam, very

dark gray (5YR 3/1) dry; moderate fine granular

structure; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; many fine, medium, and coarse roots;

many fine interstitial pores; 20 percent pebbles; strongly

acid; abrupt wavy boundary.

A2-4 to 7 inches; gray (10YR 5/1) gravelly silt loam,

light gray (10YR 7/1) dry; moderate medium

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; common

fine and medium roots; many fine interstitial pores;

30 percent rounded pebbles; strongly acid; abrupt wavy

boundary.

B21hir-7 to 11 inches; dark reddish brown (5YR 3/4) gravelly silt

loam, reddish brown (5YR 5/4) dry; moderate medium

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; common fine

and medium roots; common tubular pores; 30 percent

rounded pebbles; strongly acid; clear wavy boundary.

B22-11 to 20 inches; strong brown (7.5YR 5/6) gravelly silt

loam, reddish yellow (7.5YR 6/6) dry; weak coarse

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; common

fine and medium roots; few tubular
pores; 30 percent angular and rounded pebbles;

medium acid; clear smooth boundary.

B23-20 to 27 inches; dark brown (10YR 4/3) gravelly silt loam;

pale brown (10YR 6/3) dry; massive; slightly hard,

friable, slightly sticky and slightly plastic; weakly smeary;

few fine roots; 30 percent angular andesite pebbles;

medium acid; abrupt wavy boundary.

R-27 inches; andesite.

The mean annual soil temperature at a depth of 20

inches is 41 to 43 degrees F. Bedrock is at a depth of 20

to 40 inches.

The A1 horizon has hue of 7.5YR or 5YR and chroma of 1

to 3 when moist or dry. The A2 horizon has hue of 7.5YR or

10YR, value of 5 or 6 when moist and 6 or 7 when dry, and

chroma of 1 to 3 when moist or dry. It is gravelly silt loam,

gravelly loam, or cobbly loam.

The B horizon has value of 4 to 6 when dry and

chroma of 3 to 6 when moist or dry. It is gravelly silt

loam, gravelly loam, or cobbly loam.

Indianola series

The Indianola series consists of very deep, somewhat

excessively drained soils on terraces and outwash plains.

These soils formed in sandy glacial outwash. Slope is 15 to 25

percent. Elevation is 50 to 500 feet. The average annual

precipitation is about 40 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 180 to 200 days.

Typical pedon of Indianola loamy sand, 15 to 25

percent slopes, 1,650 feet north and 1,000 feet east of the

southwest corner of sec. 31, T. 27 N., R. 5 E.

O1-2 inches to 0; needles, leaves, and twigs.

A1-0 to 4 inches; very dark grayish brown (10YR 3/2)

loamy sand, brown (10YR 5/3) dry; weak fine granular

structure; soft, very friable, nonsticky and nonplastic; many

fine, medium, and coarse roots; common fine tubular pores;

slightly acid; clear wavy boundary.

B21ir-4 to 8 inches; dark yellowish brown (10YR 4/4) loamy

sand, light yellowish brown (10YR 6/4) dry; weak fine

granular structure; soft, very friable, nonsticky and

nonplastic; many fine and medium roots; few fine

tubular pores; slightly acid; clear wavy boundary.

B22ir-8 to 13 inches; dark yellowish brown (10YR 4/4)

loamy sand, light yellowish brown (10YR 6/4) dry;

massive; soft, very friable, nonsticky and nonplastic;

common fine and medium roots; few fine tubular pores;

slightly acid; gradual wavy boundary.

B23ir-13 to 24 inches; dark yellowish brown (10YR 4/4)

loamy sand, light yellowish brown (10YR 6/4) dry;

massive; soft, very friable, nonsticky and nonplastic; few

roots; slightly acid; abrupt smooth boundary.

C1-24 to 47 inches; light olive gray (5Y 6/2) sand, light

gray (5Y 7/2) dry; single grain; loose; few roots; few

very fine tubular pores; slightly acid; gradual smooth

boundary.

C2-47 to 60 inches; grayish brown (2.5Y 5/2) sand,

light gray (2.5Y 7/2) dry; single grain; loose; few

roots; few very fine tubular pores; slightly acid.

The estimated mean annual soil temperature is 47 to 52

degrees F. The profile is neutral to strongly acid. The control

section is less than 15 percent coarse fragments.

The A horizon has hue of 10YR or 7.5YR, value of 2 or

3 when moist and 4 to 6 when dry, and chroma of 1 to 3

when moist or dry.

The B horizon has hue of 10YR or 7.5YR, and it has value of 3

or 4 when moist and .4 to 6 when dry. It is loamy fine

sand or loamy sand.

The C horizon has hue of 2.5Y or 5Y, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist or dry. It is loamy fine sand to sand.

Kitsap series

The Kitsap series consists of very deep, moderately well

drained soils on terraces and terrace escarpments. These

soils formed in lacustrine sediment. Slope is 0 to 50

percent. Elevation ranges from near sea level to 500 feet.

The average annual precipitation is about 40 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free season is 160 to 200 days.

Typical pedon of Kitsap silt loam, 0 to 8 percent

slopes, 1,400 feet north and 1,250 feet west of the

southeast corner of sec. 32, T. 27 N., R. 5 E.

Ap-0 to 6 inches; dark grayish brown (10YR 4/2) silt loam, grayish

brown (10YR 5/2) dry; moderate fine granular structure;

slightly hard, friable, slightly sticky and slightly plastic; many

very fine and fine roots and common medium roots;

common fine pores; medium acid; abrupt smooth

boundary.

B21-6 to 12 inches; dark brown (10YR 4/3) silt loam, pale

brown (10YR 6/3) dry, moderate fine subangular blocky

structure; slightly hard, friable, slightly sticky and slightly

plastic; many very fine and fine roots; common fine

pores; slightly acid; clear wavy boundary.

B22-12 to 20 inches; dark brown (10YR 4/3) silt loam,

pale brown (10YR 6/3) dry; many medium distinct dark

brown (7.5YR 4/4) mottles; moderate medium

subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; common fine roots;

few fine pores; slightly acid; clear wavy boundary.

B3-20 to 33 inches; olive brown (2.5Y 4/4) silty clay loam,

light yellowish brown (2.5Y 6/4) dry; many large

prominent strong brown (7.5YR 5/6) mottles; moderate

medium subangular blocky structure; hard, firm, sticky

and plastic; few fine roots; few fine pores; slightly acid;

clear smooth boundary.

C-33 to 60 inches; light olive brown (2.5Y 5/4) silty clay

loam, pale yellow (2.5Y 7/4) dry; few fine distinct
yellowish brown (10YR 5/6) mottles; massive;

hard, firm, sticky and plastic; few fine pores; finely

stratified with silt loam; slightly acid.

The estimated mean annual soil temperature at a depth

of 20 inches is 50 to 53 degrees F. The control section

averages less than 15 percent coarse fragments.

The A horizon has value of 3 or 4 when moist and 4 or 5

when dry, and it has chroma of 2 or 3 when moist or dry.

The B2 horizon has value of 4 or 5 when moist and 6 or 7

when dry, and it has chroma of 3 or 4 when moist or dry. It

is silt loam or silty clay loam. The B3 horizon has hue of

10YR or 2.5Y, value of 4 or 5 when moist and 6 or 7 when

dry, and chroma of 3 or 4 when moist or dry. It is silt loam

or silty clay loam.

The C horizon has hue of 10YR, 5Y, or 2.5Y, value of 5 or 6

when moist and 7 or 8 when dry, and chroma of 3 or 4 when

moist or dry. It is stratified silt loam or silty clay loam. Some

pedons contain strata of fine sand or silty clay.

Lynnwood series

The Lynnwood series consists of very deep, somewhat

excessively drained soils on terraces, terrace escarpments, and

outwash plains. These soils formed in glacial outwash. Slope

is 0 to 90 percent. Elevation is 50 to 500 feet. The average

annual precipitation is about 40, the average annual air

temperature is about 50 degrees F, and the average frost-free

season is 180 to 200 days.

Typical pedon of Lynnwood loamy sand, 0 to 3 percent

slopes, about 5 miles north of Arlington, 2,600 feet

west and 980 feet north of the southeast corner of sec.

22, T. 32 N., R. 5 E.

O1-3 to 2 inches; leaves, needles, and twigs.

O2-2 inches to 0; decomposed mat of needles, twigs,

and leaves.

A2-0 to 1 inch; grayish brown (10YR 5/2) loamy sand,

light gray (10YR 7/2) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; common fine and medium roots; many very fine

pores; strongly acid; clear smooth boundary.

B21ir-1 inch to 7 inches; dark brown (7.5YR 4/4) loamy

sand, light brown (7.5YR 6/4) dry; weak medium

subangular blocky structure; soft, very friable, nonsticky and

nonplastic; common fine and medium roots; many very

fine pores; many semiround concretions 1 /2 to 1 millimeters

in size; strongly acid; clear smooth boundary.

B22ir-7 to 15 inches; dark brown (7.5YR 4/4) loamy sand,

light brown (7.5YR 6/4) dry; weak medium subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; common fine and medium roots; many

very fine interstitial pores; strongly acid; clear smooth

boundary.

B3-15 to 29 inches; dark yellowish brown (10YR 4/4) loamy sand,

light yellowish brown (10YR 6/4) dry; massive; soft, very

friable, nonsticky and nonplastic; common fine and

medium roots; slightly acid; abrupt smooth boundary.

C-29 to 60 inches; grayish brown (2.5Y 5/2) sand, light

gray (2.5Y 7/2) dry; single grain; loose; few fine and

medium roots; medium acid.

The estimated mean annual soil temperature is 47 to 50

degrees F. The control section averages 0 to 15 percent

rock fragments.

The A2 horizon has value of 4 or 5 when moist and 6 to 8

when dry, and it has chroma of 1 to 3 when moist or dry.

The B2 horizon has hue of 7.5YR or 5YR, value of 3 to 5

when moist and 4 to 6 when dry, and chroma of 3 to 6

when moist or dry. It is loamy sand or loamy fine sand. The

B3 horizon has value of 4 or 5 when moist and 6 or 7

when dry, and it has chroma of 3 or 4 when moist or dry.

The C horizon has hue of 10YR, 2.5Y, or 5Y, value of 4 to

6 when moist and 5 to 7 when dry, and it has chroma of 2

to 4 when moist or dry. It is loamy fine sand to sand.

McKenna series

The McKenna series consists of moderately deep, poorly

drained soils in depressional areas and drainageways on till

plains. These soils formed in glacial till. Slope is 0 to 8

percent. Elevation is 100 to 800 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 150 to 180 days.

Typical pedon of McKenna gravelly silt loam, 0 to 8

percent slopes, 1,530 feet west and 2,980 feet south of the

northeast corner of sec. 23, T. 27 N., R. 5 E.

A1-0 to 8 inches; very dark grayish brown (10YR 3/2)

gravelly silt loam, dark grayish brown (10YR 4/2) dry;

moderate fine granular structure; slightly hard, friable,

slightly sticky and slightly plastic; many very fine,

medium, and coarse roots; common fine tubular pores;

20 percent pebbles; medium acid; abrupt smooth

boundary.

B21-8 to 16 inches; dark brown (10YR 4/3) gravelly silt

loam, light brownish gray (10YR 6/2) dry; few fine faint

yellowish brown (10YR 5/8) mottles; moderate medium

subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; common very fine and

fine roots; common fine tubular pores; 25 percent

pebbles; medium acid; clear smooth boundary.

B22-16 to 33 inches; light olive brown (2.5Y 5/4) gravelly

silt loam, light gray (2.5Y 7/2) dry; few fine faint

brownish yellow (10YR 6/6) mottles; moderate medium

subangular blocky structure; slightly hard,
friable, slightly sticky and slightly plastic; few

very fine and fine roots; 25 percent pebbles; medium

acid; abrupt smooth boundary.

Cr-33 to 60 inches; olive (5Y 5/3) dense glacial drift

that breaks to very gravelly sandy loam, light gray

(5Y 7/2) dry; many medium distinct brown (10YR 5/3)

mottles and few fine faint brownish yellow

(10YR 6/6) mottles; compact; very hard, very firm,

slightly sticky and slightly plastic; 40 percent

pebbles; slightly acid.

Thickness of the solum and depth to the compact glacial

till are 20 to 40 inches. The particle-size control section is

20 to 35 percent clay in the fine earth fraction.

The A horizon has hue of 7.5YR or 10YR, value of 2 or

3 when moist and 2 to 4 when dry, and chroma of 1 or 2

when moist or dry. The B2 horizon has hue of

10YR, 2.5Y, or 5Y, value of 3 to 5 when moist and 5 to 7 when

dry, and chroma of 2 to 4 when moist or dry. It is gravelly

silt loam, gravelly loam, or gravelly clay loam. The Cr

horizon is 35 to 65 percent gravel.

The McKenna soils in this survey area are taxadjunct to the

McKenna series because they have slightly less than 35

percent rock fragments in the control section. This

difference, however, does not affect the use and

management of the soils.

Menzel series

The Menzel series consists of very deep, well drained

soils on terraces. These soils formed in alluvium and

volcanic ash. Slope is 0 to 3 percent. Elevation is 200 to 500

feet. The average annual precipitation is about 55 inches,

the average annual air temperature is about 49 degrees

F, and the average frost-free season is 140 to 200 days.

Typical pedon of Menzel silt loam, 0 to 3 percent

slopes, 600 feet east and 450 feet north of the

southwest corner of sec. 32, T. 30 N., R. 7 E.

O1-1/2 inch to 0; thick matted roots.

Ap-0 to 4 inches; very dark brown (10YR 2/2) silt loam,

dark grayish brown (10YR 4/2) dry; moderate fine granular

structure; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; many very fine roots, common fine

roots, and few medium and coarse roots; slightly acid; clear

wavy boundary.

B2-4 to 9 inches; strong brown (7.5YR 5/6) silt loam,

brownish yellow (10YR 6/6) dry; moderate coarse

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; many very

fine roots and common fine, medium, and coarse roots;

slightly acid; clear wavy boundary.

B3-9 to 16 inches; dark yellowish brown (10YR 4/4) very

fine sandy loam, pale yellow (2.5Y 7/4) dry; weak

coarse subangular blocky structure; slightly hard, firm,

slightly sticky and slightly plastic; weakly smeary; many very

fine roots and common fine,

medium, and coarse roots; slightly acid; gradual wavy

boundary.

C1-16 to 31 inches; light olive brown (2.5Y 5/4) fine

sandy loam, pale yellow (5Y 7/3) dry; massive;

slightly hard, firm, slightly sticky and slightly plastic;

common very fine, fine, medium, and coarse roots;

slightly acid; abrupt wavy boundary.

C2-31 to 60 inches; light olive brown (2.5Y 5/3) fine

sandy loam, pale yellow (2.5Y 7/4) dry; massive;

soft, friable, slightly sticky and nonplastic; thin

discontinuous strata of loamy sand and loamy fine

sand 1/2 to 1 inch thick; few very fine and fine roots;

neutral.

The mean annual soil temperature at a depth of 20 inches is 48

to 52 degrees F. The control section is 0 to 10 percent rock

fragments.

The A horizon has hue of 10YR or 7.5YR, value of 2 or

3 when moist and 4 or 5 when dry, and chroma of 1 or 2

when moist or dry.

The B2 horizon has hue of 10YR or 7.5YR, value of 4 to 7 when

moist or dry, and chroma of 4 to 6 when moist or dry. It is

silt loam, very fine sandy loam, or loam. The B3 horizon is

silt loam, very fine sandy loam, or loam.

The C horizon has hue of 10YR, 5Y, or 2.5Y, and it has

value of 4 to 6 when moist and 5 to 7 when dry. It is silt

loam, very fine sandy loam, or fine sandy loam.

Mukilteo series

The Mukilteo series consists of very deep, very poorly

drained organic soils in depressional areas. These soils

formed in organic material derived dominantly from sedges.

Slope is 0 to 1 percent. Elevation is 20 to 1,000 feet. The

average annual precipitation is about 55 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free season is 150 to 200 days.

Typical pedon of Mukilteo muck, 1,200 feet east and 800

feet north of the southwest corner of sec. 25, T. 28 N., R. 6

E.

Oe1-0 to 4 inches; dark reddish brown (5YR 2/2, on

broken faces) muck; about 40 percent fibers, 15

percent rubbed; weak fine subangular blocky

structure; slightly hard, friable, slightly sticky and

slightly plastic; many fine and medium roots; very

strongly acid; abrupt wavy boundary.

Oe2-4 to 8 inches; dark reddish brown (5YR 2/2 and 3/2,

on broken faces) rubbed and pressed hemic material;

about 45 percent fibers, 20 percent rubbed; weak

medium subangular blocky structure; slightly hard,

friable, slightly sticky and slightly plastic; common fine

and medium roots; very strongly acid; clear smooth

boundary.

Oe3-8 to 13 inches; dark reddish brown (5YR 2/2 and

3/2, on broken faces), rubbed and pressed hemic

material; about 55 percent fibers, 25 percent rubbed;
moderate medium subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; common

very fine and fine roots; very strongly acid; clear

smooth boundary.

Oe4-13 to 27 inches; black (5YR 2/1, on broken faces)

rubbed and pressed hemic material; about 40 percent fibers,

18 percent rubbed; massive; hard, friable, nonsticky and

nonplastic; very strongly acid; abrupt smooth boundary.

Oe5-27 to 35 inches; black (5YR 2/1, on broken faces)

rubbed and pressed hemic material; about 78 percent fibers,

40 percent rubbed; massive; hard, friable, nonsticky and

nonplastic; very strongly acid; abrupt smooth boundary.

Oa1-35 to 54 inches; black (5YR 2/1, on broken faces)

rubbed and pressed sapric material; about 15 percent

fibers, less than 5 percent rubbed; massive; hard,

friable, nonsticky and nonplastic; very strongly acid;

abrupt smooth boundary.

Ilc-54 to 60 inches; olive gray (5Y 5/2) fine sandy

loam, light gray (5Y 7/2) when dry; massive; soft,

very friable, nonsticky and nonplastic; neutral.

The organic material is 52 inches to more than 60 inches

thick. The estimated soil temperature at a depth of 20

inches is 46 to 52 degrees F. These soils are usually

saturated with water. Fibers are mainly sedge.

The surface tier has hue of 5YR or 7.5YR, value of 2 or 3,

and chroma of 1 or 2. It commonly has one or more layers

of sapric material that has less than 15 percent fiber when

rubbed. It has weak to moderate blocky structure. The

subsurface tiers are hemic material that have hue of 5YR

to 10YR and have value and chroma of 1 to 4. The rubbed

fiber content ranges from 18 to 50 percent. The bottom tier

is similar in color and fiber content to the subsurface tier, but

it generally is higher in fiber content.

Nargar series

The Nargar series consists of very deep, well drained

soils on high terraces and terrace escarpments. These soils

formed in sandy alluvium and volcanic ash. Slope is 0 to

90 percent. Elevation is 400 to 1,200 feet. The average

annual precipitation is about 65 inches, the average annual

air temperature is about 46 degrees F, and the average frostfree season is 120 to 180 days.

Typical pedon of Nargar fine sandy loam, 0 to 15 percent

slopes, 1,000 feet west and 2,600 feet north of the

southeast corner of sec. 2, T. 32 N., R. 7 E.

O1-1 to 1/2 inch; needles, leaves, and twigs.

O2-1/2 inch to 0; black (10YR 2/1) decomposed litter.

A2-0 to 1 inch; gray (5YR 5/1) very fine sandy loam, light

gray (5YR 7/1) dry; massive; hard, firm, slightly sticky

and nonplastic; common very fine, fine, medium, and

coarse roots; common very fine vesicular pores; slightly

acid; abrupt irregular boundary.

B21ir-1 inch to 8 inches; yellowish red (5YR 5/8) fine

sandy loam, strong brown (7.5YR 5/6) dry; yellowish red

(5YR 4/6) stains on 20 percent of faces of peds;

moderate coarse subangular blocky structure;

slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; common very fine, fine, and

medium roots and few coarse roots; common very fine

vesicular pores; 10 percent shot 2 to 5 millimeters in

size; slightly acid; clear wavy boundary.

B22-8 to 15 inches; dark brown (7.5YR 4/4) fine sandy

loam, strong brown (7.5YR 5/6) dry; moderate medium

subangular blocky structure; hard, very firm, slightly sticky

and slightly plastic; weakly smeary; common very

fine, fine, and medium roots and few coarse roots; few

very fine vesicular pores; 5 percent shot 2 to 5

millimeters in size; medium acid; clear wavy boundary.

B23-15 to 26 inches; dark yellowish brown (10YR 4/4) fine

sandy loam, yellowish brown (10YR 5/4) dry; weak

medium subangular blocky structure; slightly hard,

friable, slightly sticky and slightly plastic; weakly

smeary; common very fine, fine, and medium roots

and few coarse roots; few very fine vesicular pores;

slightly acid; clear wavy boundary.

IlC1-26 to 41 inches; olive gray (5Y 4/2) fine sand, olive

(5Y 5/3) dry; single grain; loose; few very fine, fine,

and medium roots; 30 percent weakly cemented fine

sand nodules 2 to 3 millimeters in size; slightly acid;

abrupt smooth boundary.

IIC2-41 to 47 inches; light olive brown (2.5Y 5/4) very

gravelly loamy coarse sand, pale olive (5Y 6/3) dry;

single grain; loose; few very fine and fine roots; 50

percent fine rounded pebbles; slightly acid; clear

smooth boundary.

IIC3-47 to 60 inches; olive gray (5Y 5/2). very gravelly

loamy coarse sand, light olive gray (5Y 6/2) dry; single

grain; loose; 50 percent fine rounded pebbles; slightly

acid.

The estimated mean annual soil temperature at a depth

of 20 inches is 47 to 50 degrees F. The solum is 15 to 40

inches thick. It averages 0 to 15 percent rock fragments.

The A2 horizon has hue of 5YR, 7.5YR, or 10YR, and it

has value of 4 or 5 when moist and 6 or 7 when dry. The B2

horizon is loam, fine sandy loam, or sandy loam. The IIC

horizon has hue of 10YR, 5Y, or 2.5Y. It is stratified with

loamy coarse sand to fine and coarse sand. Individual strata

are 0 to 60 percent coarse fragments, but the horizon

averages 15 to 50 percent.

Nargar Variant

The Nargar Variant consists of very deep, well drained

soils on terrace escarpments and mountainsides. These

soils formed in sandy alluvium and volcanic ash. Slope is 3

to 30 percent. Elevation is 800 to 1,800 feet. The
average annual precipitation is about 70 inches, the

average annual air temperature is about 45 degrees F, and the

average frost-free season is 110 to 140 days.

Typical pedon of Nargar Variant sandy loam, 3 to 30

percent slopes, 1,300 feet north and 1,350 feet east of the

southwest corner of sec. 3, T. 31 N., R. 6 E.

O1-2 inches to 0; black (10YR 2/1) leaves, twigs, and

needles.

A1-0 to 4 inches; very dark grayish brown (10YR 3/2)

sandy loam, grayish brown (10YR 5/2) dry; massive;

slightly hard, friable, nonsticky and nonplastic; weakly smeary;

many fine, medium, and coarse roots; many very fine pores;

medium acid; abrupt wavy boundary.

B21ir-4 to 11 inches; reddish brown (5YR 5/4) sandy loam, light

reddish brown (5YR 6/4) dry; moderate coarse

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; common fine

and medium roots; common very fine pores; medium acid;

clear wavy boundary.

B22-11 to 18 inches; dark brown (7.5YR 4/4) sandy loam,

brown (7.5YR 5/4) dry; weak medium subangular blocky

structure; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; common fine and medium roots;

few very fine pores; medium acid; clear wavy boundary.

B23-18 to 31 inches; dark yellowish brown (10YR 4/4)

sandy loam, yellowish brown (10YR 5/4) dry; weak

medium subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; weakly smeary; common

fine and medium roots; few fine pores; slightly acid; clear

wavy boundary.

IlC1-31 to 42 inches; yellowish brown (10YR 5/4)

loamy coarse sand, light yellowish brown (10YR 6/4)

dry; single grain; loose; few fine roots; many fine

pores; slightly acid; abrupt smooth boundary.

IIC2-42 to 60 inches; light olive brown (2.5Y 5/4) very

gravelly coarse sandy loam, light yellowish brown (2.5Y

6/4) dry; single grain; loose; very few fine roots; 50

percent fine round pebbles; slightly acid.

The solum is 15 to 40 inches thick and averages 0 to 15

percent coarse fragments.

The A1 horizon has hue of 10YR or 7.5YR, value of 2 or

3 when moist and 3 to 5 when dry, and chroma of 1 or 2

when moist or dry.

The B2 horizon is fine sandy loam or sandy loam.

The IIC horizon has hue of 10YR, 5Y, or 2.5Y, value of 4 or 5

when moist and 5 or 6 when dry, and chroma of 2 to 4

when moist or dry. It is stratified coarse sandy loam to fine

coarse sand. Individual strata are 0 to 60 percent coarse

fragments, but the horizon averages 15 to 50 percent.

Norma series

 The Norma series consists of very deep, poorly drained

soils in depressional areas on outwash plains

and till plains. These soils formed in alluvium. Slope is 0 to 3

percent. Elevation is 20 to 600 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 150 to 200 days.

Typical pedon of Norma loam, 2,350 feet north and

1,590 feet west of the southeast corner of sec. 29, T. 27 N.,

R. 5 E.

Ap-0 to 10 inches; very dark gray (10YR 3/1) loam,

gray (10YR 5/1) dry; moderate fine granular

structure; slightly hard, friable, slightly sticky and

slightly plastic; many fine, medium, and coarse

roots; many very fine tubular pores; slightly acid;

abrupt wavy boundary.

B2g-10 to 28 inches; dark grayish brown (2.5Y 4/2)

sandy loam, light brownish gray (2.5Y 6/2) dry; common

medium prominent yellowish brown (10YR 5/8) mottles;

weak medium subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; few fine roots;

many very fine pores; slightly acid; clear wavy

boundary.

Cg-28 to 60 inches; dark gray (5Y 4/1) sandy loam, gray

(5Y 6/1) dry; common fine prominent red (2.5YR 4/6)

and yellowish brown (10YR 5/6) mottles; massive;

slightly hard, friable, nonsticky and nonplastic; thin

loamy sand to silty clay loam strata; few roots; many

very fine pores; slightly acid.

The control section averages less than 20 percent

coarse fragments, less than 18 percent clay, and more

than 15 percent fine and coarse sand.

The B horizon is sandy loam, silt loam, or fine sandy

loam. The C horizon is stratified loamy sand to silty clay

loam.

Norma Variant

Norma Variant consists of very deep, poorly drained

soils in depressional areas on outwash plains. These soils

formed in glacial outwash. Slope is 0 to 3 percent.

Elevation is 50 to 400 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree season is 180 to 200 days.

Typical pedon of Norma Variant loam, 2,650 feet west and

50 feet north of the southeast corner of sec. 29, T. 31 N., R.

5 E.

Ap-0 to 9 inches; dark reddish brown (5YR 3/2) loam,

grayish brown (10YR 5/2) dry; moderate fine subangular

blocky structure; slightly hard, friable, slightly sticky and

slightly plastic; many fine roots; very strongly acid;

abrupt smooth boundary.

B21g-9 to 18 inches; light olive gray (5Y 6/2) sandy clay

loam, light gray (5Y 7/2) dry; common medium distinct

yellowish red (5YR 4/6) mottles, reddish yellow (5YR

6/6) dry; moderate medium subangular
blocky structure; slightly hard, friable, slightly sticky and

slightly plastic; common fine roots; many fine,

medium, and coarse interstitial pores; medium acid; clear

smooth boundary.

B22g-18 to 26 inches; grayish brown (2.5Y 5/2) sandy clay

loam, light brownish gray (2.5Y 6/2) dry; many coarse

prominent yellowish red (5YR 4/6) mottles, reddish

yellow (5YR 6/6) dry; moderate medium subangular

blocky structure; slightly hard, friable, slightly sticky and

slightly plastic; common fine roots; many fine, medium,

and coarse pores; medium acid; abrupt smooth boundary.

C1g-26 to 35 inches; olive gray (5Y 5/2) sandy loam,

light olive gray (5Y 6/2) dry; common fine distinct

strong brown (7.5YR 5/8) mottles, reddish yellow

(7.5YR 6/8) dry; massive; slightly hard, friable,

slightly sticky and nonplastic; few fine roots; many fine,

medium, and coarse pores; slightly acid; clear smooth

boundary.

C2g-35 to 60 inches; olive gray (5Y 5/2) loamy sand, light

olive gray (5Y 6/2) dry; single grain; loose; few fine

pores; slightly acid.

The upper part of the control section is 20 to 35

percent clay. The lower part is sandy loam or loamy

sand.

The A horizon has hue of 5YR, 7.5YR, or 10YR, value of 2 or 3

when moist and 3 to 5 when dry, and chroma of 1 or 2 when

moist or dry. The B2g horizon has hue of 2.5Y or 5Y, value

of 4 to 7 when moist and 5 to 8 when dry, and chroma of 1

or 2 when moist or dry. It is sandy clay loam or clay loam.

The C horizon is sandy loam, loamy sand, or loamy fine

sand.

Ogarty series

The Ogarty series consists of moderately deep,

moderately well drained soils on foothills and mountain

sides. These soils formed in volcanic ash and material

weathered from andesite. Slope is 2 to 60 percent.

Elevation is 500 to 1,000 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 46 degrees F, and the average

frost-free season is 140 to 180 days.

Typical pedon of Ogarty very gravelly loam, 1,800 feet

east and 2,100 feet north of the southwest corner of sec. 3,

T. 28 N., R. 7 E.

O1-1 1/2 inches to 1/2 inch; forest litter.

O2-1/2 inch to 0; decomposed litter.

A1-0 to 1 inch; very dark gray (10YR 3/1) very gravelly

loam, gray (10YR 5/1) dry; moderate medium granular

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; common very fine, fine, medium, and coarse

roots; many very fine discontinuous pores; 15 percent

cobbles and 40 percent fine pebbles; very strongly

acid; abrupt wavy boundary.

B21-1 inch to 10 inches; dark brown (7.5YR 4/4) very

gravelly loam, yellowish brown (10YR 5/4) dry; weak very

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common very

fine, fine, medium, and coarse roots; many very fine

discontinuous pores; 10 percent cobbles, 45 percent

pebbles, and 10 percent shot 2 to 5 millimeters in size;

medium acid; clear broken boundary.

B22-10 to 20 inches; dark brown (7.5YR 4/4) extremely

gravelly loam, light yellowish brown (10YR 6/4) dry;

moderate and weak medium subangular blocky structure;

soft, very friable, slightly sticky and slightly plastic;

weakly smeary; common very fine, fine, medium, and

coarse roots; many very fine discontinuous pores; 10

percent cobbles, 60 percent fine angular pebbles, and

10 percent shot 2 to 5 millimeters in size; medium acid;

gradual wavy boundary.

B3-20 to 32 inches; brown (7.5YR 5/4) extremely

gravelly loam, light yellowish brown (10YR 6/4); weak

fine granular structure; soft, very friable, slightly

sticky and slightly plastic; weakly smeary; common

very fine, fine, medium, and coarse roots; common

very fine discontinuous pores; 75 percent fine angular

pebbles and 5 percent shot 2 to 5 millimeters in size;

medium acid; clear wavy boundary.

C1-32 to 35 inches; dark brown (7.5YR 4/4) extremely

gravelly loam, yellowish brown (10YR 5/6) dry;

massive; soft, very friable, slightly sticky and slightly

plastic; weakly smeary; common very fine and fine

roots and few medium and coarse roots; few pores; 70

percent fine angular pebbles; medium acid; clear broken

boundary.

C2-35 to 38 inches; yellowish red (5YR 4/6) extremely

gravelly loam, yellowish brown (10YR 5/6) dry; massive;

soft, very friable, slightly sticky and slightly plastic;

weakly smeary; few very fine, fine, medium, and

coarse roots; few pores; 90 percent angular pebbles;

medium acid; abrupt smooth boundary.

R-38 inches; andesite.

The estimated mean annual soil temperature at a

depth of 20 inches is 47 to 50 degrees F. Depth to

bedrock ranges from 20 to 40 inches.

The A horizon has value of 2 or 3 when moist and 4 or 5

when dry, and it has chroma of 1, 2, or 3 when moist or dry.

The B and C horizons have hue of 5YR to 10YR, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 4 to 6 when

moist or dry. They are very gravelly loam or extremely

gravelly loam.

Olomount series

The Olomount series consists of moderately deep,

moderately well drained soils on mountainsides and

ridgetops. These soils formed in glacial till, volcanic ash,
and material weathered dominantly from andesite, argillite, and

basalt. Slope is 3 to 90 percent. Elevation is 800 to 1,800

feet. The average annual precipitation is about 70 inches,

the average annual air temperature is about 44 degrees F,

and the average frost-free season is 130 to 150 days.

Typical pedon of Olomount gravelly loam, 3 to 15 percent

slopes, 1,400 feet east and 2,300 feet south of the

northwest corner of sec. 33, T. 31 N., R. 7 E.

O1-2 1/2 to 2 inches; leaves, needles, and mosses.

O2-2 inches to 0; partially decomposed litter.

A1 -0 to 2 inches; very dark grayish brown (10YR 3/2) gravelly

loam, grayish brown (10YR 5/2) dry; moderate fine

granular structure; slightly hard, friable, slightly sticky and

slightly plastic; weakly smeary; common fine and medium

roots; many fine interstitial pores; 20 percent pebbles;

strongly acid; clear smooth boundary.

B21ir-2 to 7 inches; reddish brown (5YR 5/4) gravelly loam,

light reddish brown (5YR 6/4) dry; weak medium

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; common fine

and medium roots; few fine interstitial pores; 20 percent

pebbles; medium acid; clear smooth boundary.

B22-7 to 18 inches; dark brown (7.5YR 4/4) gravelly

loam, brown (7.5YR 5/4) dry; weak medium

subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; weakly smeary; few

fine and medium roots; few fine interstitial pores; 20

percent pebbles; medium acid; clear smooth boundary.

C1-18 to 27 inches; dark brown (7.5YR 4/4) very

gravelly loam, brown (7.5YR 5/4) dry; massive;

slightly hard, friable, slightly sticky and slightly plastic;

weakly smeary; few fine and medium roots; 60 percent

pebbles; slightly acid; clear smooth boundary.

C2-27 to 32 inches; dark brown (7.5YR 4/4) extremely

gravelly loam, brown (7.5YR 5/4) dry; massive; slightly

hard, friable, slightly sticky and slightly plastic; weakly

smeary; few fine roots; 80 percent pebbles; slightly acid;

abrupt smooth boundary.

IIR-32 inches; andesite.

The mean annual soil temperature at a depth of 20

inches ranges from 45 to 47 degrees F. Depth to

bedrock ranges from 20 to 40 inches. The control

section is 35 to 60 percent coarse fragments.

The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 when

moist and 4 or 5 when dry, and chroma of 2 or 3 when

moist or dry.

The B horizon has value of 2 to 5 when moist. and 3 to 6

when dry, and it has chroma of 3 to 6 when moist or dry. It

is gravelly loam, cobbly loam, or gravelly silt loam.

The C horizon has hue of 10YR or 7.5YR, value of 4 or 5

when moist and 5 or 6 when dry, and chroma of 3

to 6 when moist or dry. It is extremely gravelly loam,

extremely gravelly silt loam, or very gravelly silt loam.

Orcas series

The Orcas series consists of very deep, very poorly

drained soils in basins on hills. These soils formed in

sphagnum moss. Slope is 0 to 2 percent. Elevation is 100

to 500 feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and the average frost-free season is 160 to 180

days.

Typical pedon of Orcas peat, 2,190 feet north and 2,125

feet east of the southwest corner of sec. 18, T. 30 N., R. 7

E.

Oi1-0 to 3 inches; dark reddish brown (5YR 2/2, broken

face) fibric material, dark reddish brown (5YR 3/4)

pressed and rubbed; about 90 percent fibers, 80

percent rubbed; weak thick platy structure; soft, very

friable, nonsticky and nonplastic; many very fine and

fine roots; extremely acid; clear smooth boundary.

Oi2-3 to 12 inches; dark brown (7.5YR 3/2, broken face)

fibric material pressed and rubbed; about 95 percent

fibers, 90 percent rubbed; weak thick platy structure;

soft, friable, nonsticky and nonplastic; few fine roots;

extremely acid; abrupt smooth boundary.

0i3-12 to 60 inches; dark brown (7.5YR 4/4, broken face)

fibric material, reddish yellow (7.5YR 7/6) pressed and

rubbed; about 95 percent fibers, 90 percent rubbed;

massive; soft, friable, nonsticky and nonplastic;

extremely acid.

The estimated mean annual soil temperature is 47 to 50

degrees F.

The surface tier is muck, peat, or mucky peat. It has hue

of 2.5YR or 5YR, value of 2 or 3 when moist, and chroma

of 2 to 4 when moist. The subsurface tier has hue of 5YR

to 10YR, and it has value and chroma of 3 to 7 when

moist.

Oso series

The Oso series consists of moderately deep, moderately

well drained soils on mountainsides and ridgetops. These

soils formed in glacial till, volcanic ash, and material

weathered from andesite. Slope is 3 to 90 percent.

Elevation is 1,800 to 2,600 feet. The average annual

precipitation is about 85 inches, the average annual air

temperature is about 43 degrees F, and the average frostfree season is 90 to 120 days.

Typical pedon of Oso gravelly loam, 3 to 15 percent

slopes, 1,500 feet west and 1,700 feet north of the

southeast corner of sec. 7, T. 28 N., R. 9 E.

O1-2 inches to 0; leaves, needles, twigs, and mosses.

A1-0 to 3 inches; black (10YR 2/1) gravelly loam, very

dark brown (10YR 2/2) dry; moderate fine granular
structure; slightly hard, friable, slightly sticky and

slightly plastic; weakly smeary; many fine, medium, and

coarse roots; many fine interstitial pores; 20 percent

pebbles; extremely acid; abrupt wavy boundary.

A2-3 to 5 inches; light brownish gray (10YR 6/2) gravelly

loam, light gray (10YR 7/2) dry; moderate fine

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; many fine,

medium, and coarse roots; few fine tubular pores; 20

percent pebbles; very strongly acid; abrupt wavy boundary.

B21ir-5 to 9 inches; dark brown (7.5YR 4/4) gravelly loam,

brown (7.5YR 5/4) dry; moderate medium

subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; weakly smeary;

common medium and coarse roots; common fine

interstitial pores; 30 percent pebbles; strongly acid; clear

wavy boundary.

B22-9 to 20 inches; yellowish brown (10YR 5/4) gravelly

loam, light yellowish brown (10YR 6/4) dry; moderate

medium subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; weakly smeary;

common medium and coarse roots; common fine

interstitial pores; 20 percent pebbles; strongly acid; clear

wavy boundary.

B3-20 to 29 inches; yellowish brown (10YR 5/4) gravelly

loam, light yellowish brown (10YR 6/4) dry; massive;

slightly hard, friable, slightly sticky and slightly plastic;

weakly smeary; few medium and coarse roots; few fine

tubular pores; 35 percent pebbles; strongly acid; abrupt

wavy boundary.

R-29 inches; unweathered andesite.

Depth to bedrock ranges from 20 to 40 inches. The

control section is 5 to 35 percent coarse fragments.

The A1 horizon has hue of 10YR or 7.5YR and value of

2 or 3 when moist or dry. The A2 horizon has hue of 10YR

or 7.5YR, value of 5 or 6 when moist and 6 or 7 when dry,

and chroma of 2 or 3 when moist or dry.

The B horizon has hue of 10YR, 7.5YR, or 5YR, value of 3

to 5 when moist and 4 to 6 when dry, and chroma of 3 to 6

when moist or dry. It is gravelly silt loam, cobbly loam,

gravelly loam, silt loam, or loam.

Pastik series

The Pastik series consists of very deep, moderately well drained

soils on terraces. These soils formed in lake sediment and

volcanic ash. Slope is 0 to 50 percent. Elevation is 200 to

800 feet. The average annual precipitation is about 50 inches,

the average annual air temperature is about 46 degrees F, and the

average frost-free season is 140 to 200 days.

Typical pedon of Pastik silt loam, 0 to 8 percent

slopes, 1,550 feet north and 1,200 feet east of the

southwest corner of sec. 31, T. 28 N., R. 8 E. (fig. 5).

Figure 5.-Typical profile of Pastik silt loam, 0 to 8

percent slopes.

Ap-0 to 6 inches; dark brown (7.5YR 3/2) silt loam, brown

(7.5YR 5/2) dry; weak fine granular structure; soft, very

friable, slightly sticky and slightly plastic; weakly

smeary; many very fine and fine roots; common very

fine and fine interstitial pores; slightly acid; abrupt smooth

boundary.

B21-6 to 14 inches; dark brown (7.5YR 4/4) silt loam,

brown (7.5YR 5/4) dry; moderate fine subangular

blocky structure; slightly hard, friable, slightly sticky

and slightly plastic; weakly smeary; common fine and

medium roots; few fine tubular pores; medium acid;

clear wavy boundary.

B22-14 to 20 inches; yellowish brown (10YR 5/4) silt

loam, light yellowish brown (10YR 6/4) dry; few

medium distinct dark brown (7.5YR 4/4) mottles, light

brown (7.5YR 6/4) dry; moderate medium subangular

blocky structure; slightly hard, friable, slightly sticky

and slightly plastic; weakly smeary;
common fine and medium roots; few very fine

tubular pores and common fine tubular pores;

medium acid; clear wavy boundary.

B23-20 to 29 inches; yellowish brown (10YR 5/4) silt

loam, light yellowish brown (10YR 6/4) dry; few

medium distinct dark brown (7.5YR 4/4) mottles, light

brown (7.5YR 6/4) dry, and few medium distinct

reddish yellow (7.5YR 6/6) mottles, reddish yellow

(7.5YR 8/6) dry; moderate medium subangular blocky

structure; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; few fine roots; few fine tubular

pores; medium acid; abrupt smooth boundary.

C-29 to 60 inches; light olive gray (5Y 6/2) silt loam,

light gray (5Y 7/2) dry; few fine distinct yellowish

brown (10YR 5/6) and strong brown (7.5YR 5/6)

mottles, brownish yellow (10YR 6/6) and reddish yellow

(7.5YR 6/6) dry; massive; slightly hard, friable, slightly

sticky and slightly plastic; few fine tubular pores;

medium acid.

The mean annual soil temperature at a depth of 20 inches

is 47 to 51 degrees F. The solum is 20 to 40 inches thick.

The 10- to 40-inch control section is 0 to 5 percent rock

fragments.

The A horizon has hue of 10YR or 7.5YR, value of 3 to 5

when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist or dry.

The B2 horizon has hue of 10YR or 7.5YR, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 3 to 5 when

moist or dry. It is loam or silt loam.

The C horizon has hue of 5Y or 2.5Y, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist or dry. It is silt loam or silty clay loam.

Pilchuck series

The Pilchuck series consists of very deep, somewhat

excessively drained soils on flood plains. These soils formed

in alluvium. Slope is 0 to 3 percent. Elevation is 20 to 800

feet. The average annual precipitation is about 45 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free season is 160 to 200 days.

Typical pedon of Pilchuck loamy sand, 2,400 feet east

and 300 feet south of the northwest corner of sec. 10, T. 27

N., R. 7 E.

A1-0 to 2 inches; dark grayish brown (2.5Y 4/2) loamy

sand, light brownish gray (2.5Y 6/2) dry; weak fine and

medium subangular blocky structure; soft, very friable,

nonsticky and nonplastic; common fine roots; few fine

discontinuous pores; slightly acid; abrupt wavy boundary.

C1-2 to 4 inches; olive gray (5Y 4/2) fine sandy loam,

light olive gray (5Y 6/2) dry; weak fine subangular

blocky structure; soft, friable, slightly sticky and

slightly plastic; common fine roots; slightly acid;

abrupt wavy boundary.

C2-4 to 31 inches; black (10YR 2/1), dark gray (10YR

4/1), grayish brown (10YR 5/2), light gray (10YR 7/2),

and yellow (10YR7/6) loamy sand, black (10YR 2/1),

yellow (10YR 7/6), dark gray (10YR 4/1), and white

(10YR 8/2) dry; single grain; loose; between depths of

15 and 17 inches is an old erosional surface that has a

mat of roots; common fine to medium roots and few

coarse roots; olive yellow (2.5Y 6/6) mica flakes less

than 5 millimeters across; slightly acid; clear smooth

boundary.

C3-31 to 34 inches; light gray (10YR 7/2), gray (10YR 5/1),

very dark gray (10YR 3/1), and very pale brown

(10YR 7/4) fine sand, light gray (10YR 7/2), dark gray

(10YR 4/1), very pale brown (10YR 7/4), and white

(10YR 8/2) dry; massive; loose; scattered pieces of

bark less than 50 millimeters across; common fine to

medium roots and few coarse roots; olive yellow (2.5Y

6/6) mica flakes less than 5 millimeters across; slightly

acid; clear smooth boundary.

C4-34 to 50 inches; light gray (10YR 7/1), very dark

grayish brown (10YR 3/2), yellow (10YR 7/6), and very

pale brown (10YR 7/4) fine sand, light gray (10YR 7/1),

dark gray (10YR 4/1), gray (10YR 5/1), and light

yellowish brown (10YR 6/4) dry; single grain; loose; few

medium and coarse roots; olive yellow (2.5Y 6/6) mica

flakes less than 5 millimeters across; slightly acid;

abrupt wavy boundary.

C5-50 to 60 inches; light gray (10YR 7/1), very dark

grayish brown (10YR 3/2), yellow (10YR 7/6), and very

pale brown (10YR 7/4) gravelly sand, light gray (10YR

7/1), dark gray (10YR 4/1), gray (10YR 5/1), and light

yellowish brown (10YR 6/4) dry; olive yellow (2.5Y 6/6)

mica flakes less than 5 millimeter across; 30 percent

rounded granite pebbles; slightly acid.

The mean annual soil temperature at a depth of 20

inches ranges from 48 to 52 degrees F. The control

section is 0 to 15 percent coarse fragments.

The A horizon has hue of 10YR, 2.5Y, or 5Y, value of 2 to

4 when moist and 3 to 6 when dry, and chroma of 1 or 2

when moist or dry.

The C horizon has hue of 10YR, 2.5Y, or 5Y, value of 2 to

8 when moist or dry, and chroma of 1 to 6 when moist or

dry. The C2 through C5 horizons are loamy sand to fine

sand. The lower part of the C horizon is gravelly or very

gravelly.

Potchub series

The Potchub series consists of moderately deep,

moderately well drained soils on mountainsides and

ridgetops. These soils formed in glacial till and volcanic ash.

Slope is 3 to 90 percent. Elevation is 2,600 to 3,600 feet.

The average annual precipitation is about 90 inches, the

average annual air temperature is about 41
degrees F, and the average frost-free season is 90 to 100

days.

Typical pedon of Potchub silt loam, 3 to 30 percent slopes,

2,000 feet west and 600 feet north of the southeast corner

of sec. 34, T. 32 N., R. 7 E.

O1-9 to 7 inches; leaves, needles, and twigs.

O2-7 inches to 0; decomposed organic litter.

A1-0 to 7 inches; very dark brown (7.5YR 2/2) silt loam, dark brown

(7.5YR 3/2) dry; moderate coarse granular structure; slightly

hard, friable, slightly sticky and slightly plastic; weakly smeary;

many very fine, fine, and medium roots and common coarse

roots; many fine interstitial pores; extremely acid; abrupt wavy

boundary.

A2-7 to 10 inches; pinkish gray (7.5YR 7/2) silt loam, pinkish white

(7.5YR 8/2) dry; moderate fine subangular blocky

structure; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; many fine and medium roots

and common coarse roots; few fine tubular pores; 5 percent

pebbles; very strongly acid; abrupt wavy boundary.

B21hir-10 to 13 inches; dark reddish brown (5YR 3/3) silt loam,

reddish brown (5YR 4/3) dry; moderate medium subangular

blocky structure; slightly hard, friable, slightly sticky and

slightly plastic; weakly smeary; common fine, medium,

and coarse roots; few fine tubular pores; 5 percent

pebbles; very strongly acid; abrupt wavy boundary.

B22hir-13 to 17 inches; strong brown (7.5YR 5/6) silt loam, reddish

yellow (7.5YR 7/6) dry; reddish brown (5YR 4/4) coatings on

peds, light reddish brown (5YR 6/4) dry; moderate

medium subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; weakly smeary; common

fine, medium, and coarse roots; few fine tubular pores; 5 percent

pebbles; medium acid; abrupt wavy boundary.

B23-17 to 22 inches; strong brown (7.5YR 5/6) silt loam, light yellowish

brown (10YR 6/4) dry; dark brown (7.5YR 4/4) coatings in

cracks, dark yellowish brown (10YR 4/4) dry; slightly hard,

friable, slightly sticky and slightly plastic; weakly smeary; few

medium roots; few fine tubular pores; 5 percent pebbles;

medium acid; clear wavy boundary.

B3-22 to 34 inches; dark brown (7.5YR 4/4) silt loam, light brown

(7.5YR 6/4) dry; common fine faint strong brown (7.5YR

5/6) mottles, light brown (7.5YR 6/4) dry; massive; slightly

hard, friable, slightly sticky and slightly plastic; weakly

smeary; few fine tubular pores; 10 percent pebbles; medium

acid; abrupt smooth boundary.

IICr-34 to 60 inches; olive (5Y 5/3) dense glacial till that breaks to

gravelly sandy loam, light olive gray (5Y 6/2) dry;

extremely hard, very firm; few fine tubular pores; 20 percent

pebbles; medium acid.

The mean annual soil temperature at a depth of 20

inches is 41 to 43 degrees F. Depth to the dense glacial

till ranges from 20 to 40 inches. The control section averages

less than 15 percent coarse fragments.

The A1 horizon has hue of 10YR or 7.5YR, value of 2 or 3

when moist and 3 or 4 when dry, and chroma of 1 or 2 when

moist or dry. The A2 horizon has hue of 10YR or 7.5YR, value of 5 to

7 when moist and 6 to 8 when dry, and chroma of 2 to 4 when

moist or dry. The B horizon is silt loam or loam. The C horizon has hue

of 5Y or 2.5Y, value of 5 or 6 when moist and 6 or 7 when dry, and

chroma of 2 or 3 when moist or dry.

Puget series

The Puget series consists of very deep, poorly drained soils in

depressional areas on flood plains. These soils formed in alluvium.

Slope is 0 to 2 percent. Elevation ranges from near sea level to 650

feet. The average annual precipitation is about 40 inches, the average

annual air temperature is about 50 degrees F, and the average frostfree season is 180 to 200 days.

Typical pedon of Puget silty clay loam, 188 feet north and 1,100 feet

east of the southwest corner of sec. 8, T. 31 N., R. 5 E.

Ap-0 to 9 inches; dark grayish brown (2.5Y 4/2) silty clay loam, light

brownish gray (2.5Y 6/2) dry; moderate medium and

coarse granular structure; very hard, friable, sticky and

plastic; many fine roots; many fine and medium tubular

pores and many micro interstitial pores; neutral; abrupt smooth

boundary.

C1-9 to 32 inches; olive gray (5Y 5/2) silty clay loam, light gray (5Y

7/1) dry, many medium distinct dark reddish brown (5YR

3/3) mottles on peds and dark yellowish brown (10YR

4/4) mottles around root channels; massive parting to very

coarse angular blocky structure; very hard, firm, sticky and

plastic; many fine roots on peds and common fine roots

in peds; few medium tubular pores; 5 to 10 percent

woody fragments; slightly acid; abrupt smooth boundary.

C2-32 to 38 inches; gray (5Y 5/1) silty clay loam, gray (5Y 6/1) dry;

many medium prominent dark reddish brown (2.5YR 2/4)

mottles on peds and dark yellowish brown (10YR 4/4)

mottles around root channels; massive; very hard, firm,

sticky and plastic; few fine roots; few fine tubular pores; slightly

acid; abrupt smooth boundary.

C3-38 to 60 inches; gray (5Y 5/1) silty clay loam, light gray (5Y 7/2)

dry; many medium prominent dark yellowish brown (10YR

4/4) and yellowish brown (10YR 5/4) mottles; moderate

fine subangular blocky structure; hard, friable, sticky and

plastic; few fine roots; many fine tubular pores; slightly acid.

The mean annual soil temperature at a depth of 20

inches is 47 to 50 degrees F. The control section

averages less than 5 percent coarse fragments, less
than 15 percent fine and coarse sand, and 18 to 35

percent clay.

The A horizon has hue of 2.5Y to 5Y, value of 3 to 5

when moist and 4 to 6 when dry, and chroma of 1 or 2 when

moist or dry. The C horizon has hue of 2.5Y or 5Y, value

of 4 to 6 when moist and 5 to 7 when dry, and chroma of 1

or 2 when moist or dry. It is silt loam, silty clay loam, or silty

clay.

Puyallup series

The Puyallup series consists of very deep, well drained soils on

stream terraces. These soils formed in alluvium of mixed origin.

Slope is 0 to 3 percent. Elevation is 20 to 500 feet. The

average annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F,

and the average frost-free season is 150 to 200 days.

Typical pedon of Puyallup fine sandy loam, 2,540 feet south

and 700 feet east of the northwest corner of sec. 5, T. 27

N., R. 8 E.

Ap-0 to 10 inches; very dark grayish brown (10YR 3/2)

fine sandy loam, grayish brown (10YR 5/2) dry; weak

medium granular structure; slightly hard, very friable, slightly

sticky and slightly plastic; many fine roots; few fine

tubular pores and common fine interstitial pores; slightly

acid; abrupt smooth boundary.

C1-10 to 16 inches; dark grayish brown (2.5Y 4/2) fine

sandy loam, grayish brown (2.5Y 5/2) dry; massive;

slightly hard, very friable, slightly sticky and slightly plastic;

few fine roots; common fine tubular and interstitial

pores; slightly acid; abrupt smooth boundary.

C2-16 to 30 inches; olive brown (2.5Y 4/4) fine sandy

loam, light yellowish brown (2.5Y 6/4) dry; many

medium distinct light brownish gray (2.5Y 6/2) mottles;

massive; slightly hard, very friable, slightly sticky and

slightly plastic; few fine roots; common fine tubular and

interstitial pores; slightly acid; abrupt smooth boundary.

C3-30 to 60 inches; dark grayish brown (2.5Y 4/2)

sand, light brownish gray (2.5Y 6/2) dry; single

grain; loose; few fine roots; many fine interstitial

pores; neutral.

The mean annual soil temperature at a depth of 20

inches is 47 to 50 degrees F.

The A horizon has hue of 10YR or 2.5Y, value of 2 or 3 when

moist and 3 to 5 when dry, and chroma of 1 to 3 when moist

or dry.

The C horizon has hue of 10YR or 2.5Y, value of 3 to 5

when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist or dry. The lower part of the C horizon ranges

from loamy sand to sand. In some pedons it is gravelly in

the lower part.

Ragnar series

The Ragnar series consists of very deep, well drained

soils on outwash plains. These soils formed in glacial

outwash. Slope is 0 to 15 percent. Elevation is 300 to 1,000

feet. The average annual precipitation is about 45 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free season is 180 to 200 days.

Typical pedon of Ragnar fine sandy loam, 0 to 8

percent slopes, 188 feet north and 1,375 feet west of the

southeast corner of sec. 22, T. 31 N., R. 5 E.

O2-1 1/2 inches to 0; partially decomposed leaves, needles,

and twigs.

A1-0 to 2 inches; dark brown (7.5YR 3/2) fine sandy

loam, brown (7.5YR 5/2) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; common fine, medium, and coarse roots;

many micro interstitial pores; slightly acid; clear smooth

boundary.

B21ir-2 to 7 inches; dark brown (7.5YR 4/4) sandy loam,

light brown (7.5YR 6/4) dry; weak medium subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; common fine and medium roots; many very

fine pores; many semiround iron concretions 1 /2 to 1

millimeter in diameter; slightly acid; clear smooth boundary.

B22ir-7 to 24 inches; dark brown (7.5YR 4/4) sandy loam,

light brown (7.5YR 6/4) dry; weak medium subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; common fine and medium roots; many very

fine interstitial pores; slightly acid; clear smooth

boundary.

C1-24 to 31 inches; dark yellowish brown (10YR 4/4)

loamy sand, light yellowish brown (10YR 6/4) dry;

massive; soft, very friable, nonsticky and nonplastic;

common fine and medium roots; slightly acid; abrupt

smooth boundary.

IIC2-31 to 60 inches; dark gray (10YR 4/1) sand, gray

(10YR 6/1) dry; single grain; loose; few fine and

medium roots; slightly acid.

The mean annual soil temperature at a depth of 20

inches ranges from 47 to 52 degrees F. The control

section is 0 to 15 percent coarse fragments.

The A horizon has hue of 10YR or 7.5YR, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 1 or 2

when moist or dry.

The B horizon has hue of 10YR or 7.5YR, value of 3 .to

5 when moist and 4 to 6 when dry, and chroma of 4 to 6

when moist or dry. It is 0 to 5 percent iron concretions and

0 to 15 percent coarse fragments.

The C horizon has hue or 10YR or 2.5Y, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 1 to 4

when moist or dry. It is 0 to 15 percent coarse fragments.
Rober series

The Rober series consists of very deep, moderately

well drained soils on terraces and terrace escarpments.

These soils formed in lacustrine sediment and volcanic

ash. Slope is 0 to 65 percent. Elevation is 800 to 1,800

feet. The average annual precipitation is about 70 inches, the

average annual air temperature is about 44 degrees F, and

the average frost-free season is 130 to 150 days.

Typical pedon of Rober silt loam, 0 to 15 percent

slopes, 1,700 feet east and 20 feet north of the

southwest corner of sec. 12, T. 30 N., R. 7 E.

O1-2 1/2 inches to 1 inch; leaves, needles, and

mosses.

O2-1 inch to 0; partially decomposed litter.

A1-0 to 3 inches; very dark brown (10YR 2/2) silt loam,

very dark grayish brown (10YR 3/2) dry; moderate fine

granular structure; slightly hard, friable, slightly sticky and

nonplastic; weakly smeary; common fine, medium, and

coarse roots; common fine tubular pores; strongly acid;

abrupt smooth boundary.

B21ir-3 to 7 inches; dark reddish brown (5YR 3/3 and 3/4) silt

loam, brown (7.5YR 5/4) and dark brown (7.5YR 4/4)

dry; moderate fine subangular blocky structure; slightly

hard, very friable, slightly sticky and slightly plastic; weakly

smeary; common fine, medium, and coarse roots; common

fine tubular pores; medium acid; abrupt smooth

boundary.

B22ir-7 to 13 inches; reddish brown (5YR 4/4) and dark

brown (7.5YR 4/4) silt loam, brown (7.5YR 5/4) and

strong brown (7.5YR 5/6) dry; common medium dark

reddish brown iron and organic stains on peds;

moderate medium subangular blocky structure; slightly hard,

very friable, slightly sticky and slightly plastic; weakly

smeary; few fine and medium roots; common fine tubular

pores; medium acid; clear smooth boundary.

B3-13 to 22 inches; yellowish brown (10YR 5/4) silt loam,

very pale brown and pale brown (10YR 7/3 and 6/3) dry;

common fine brown iron and organic stains on peds;

moderate medium subangular blocky structure; slightly hard,

friable, slightly sticky and slightly plastic; weakly smeary; few

fine and medium roots; common fine tubular pores;

slightly acid; clear smooth boundary.

C1-22 to 30 inches; grayish brown (10YR 5/2) and brown

(10YR 5/3) silty clay loam, light gray (10YR 7/2) and very

pale brown (10YR 7/3) dry; common medium faint

dark yellowish brown (10YR 4/4) mottles; massive; finely

laminated; hard, friable, slightly sticky and plastic; weakly

smeary; very few fine roots; few fine tubular pores;

medium acid; gradual smooth boundary.

C2-30 to 60 inches; grayish brown (10YR 5/2) and brown

(10YR 5/3) silty clay loam, light gray (10YR 7/2) and

very pale brown (10YR 7/3) dry; common

medium faint dark yellowish brown (10YR 4/4) mottles;

massive; hard, friable, slightly sticky and plastic;

finely stratified with silt loam; few fine tubular pores;

slightly acid.

The mean annual soil temperature at a depth of 20 inches

is 45 to 47 degrees F. The solum is 20 to 40 inches thick.

The 10- to 40-inch control section is 0 to 5 percent rock

fragments.

The A horizon has hue of 10YR or 7.5YR, value of 2 to 5

when moist and 3 to 6 when dry, and chroma of 2 or 3

when moist or dry.

The B horizon has value of 3 to 6 when moist and 4 to 7

when dry, and it has chroma of 3 to 6 when moist or dry. It

is silt loam or loam.

The C horizon has hue of 10YR, 5Y, or 2.5Y, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist or dry.

Skykomish series

The Skykomish series consists of very deep,

somewhat excessively drained soils on terraces, terrace

escarpments, and outwash plains. These soils formed in

glacial outwash and volcanic ash. Slope is 0 to 30 percent.

Elevation is 400 to 1,600 feet. The average annual

precipitation is about 65 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree season is 85 to 125 days.

Typical pedon of Skykomish gravelly loam, 0 to 30

percent slopes, 2,000 feet east and 2,150 feet south of the

northwest corner of sec. 25, T. 31 N., R. 7 E.

O1-4 to 3 inches; forest litter of leaves and twigs.

O2-3 inches to 0; decomposed forest litter.

B21hir-0 to 2 1/2 inches; dark reddish brown (5YR 3/3) gravelly

loam, dark brown (7.5YR 4/4) dry; black (5YR 2/1)

stains on 70 percent of peds; moderate coarse

subangular blocky structure; slightly hard, firm,

slightly sticky and nonplastic; weakly smeary; common

very fine, fine, medium, and coarse roots; common very

fine discontinuous pores; 20 percent rounded and

angular pebbles; very strongly acid; abrupt smooth

boundary.

B22ir-2 1/2 to 12 inches; yellowish red (5YR 4/8) gravelly loam,

light brown (7.5YR 6/4) dry; weak coarse subangular

blocky structure; slightly hard, firm, slightly sticky

and nonplastic; weakly smeary; few very fine, fine,

medium, and coarse roots; common very fine

discontinuous pores; 20 percent rounded and angular

pebbles; medium acid; clear wavy boundary.

B23ir-12 to 19 inches; yellowish red (5YR 4/6) very

gravelly fine sandy loam, reddish yellow (7.5YR 6/6)

dry; weak coarse subangular blocky structure;

slightly hard, friable, slightly sticky and nonplastic;

weakly smeary; few very fine and fine roots and
common medium and coarse roots; common very fine

discontinuous pores; 40 percent rounded and angular

pebbles; medium acid; abrupt irregular boundary.

IIC1-19 to 28 inches; dark yellowish brown (10YR 4/4)

extremely gravelly loamy coarse sand, light yellowish

brown (10YR 6/4) dry; single grain; loose; few very fine,

fine, and medium roots; 65 percent pebbles and 5

percent cobbles; very compact discontinuous layer 1

inch to 2 inches thick in upper part of horizon; medium

acid; abrupt wavy boundary.

IIC2-28 to 60 inches; very dark grayish brown (10YR 3/2)

extremely gravelly coarse sand, olive (5Y 5/3) dry;

single grain; loose; 65 percent pebbles and 5 percent

cobbles; medium acid.

The mean annual soil temperature at a depth of 20 inches

is 44 to 47 degrees F. The solum is 14 to 31 inches thick.

The upper part of the 10- to 40-inch control section is 35 to

60 percent rock fragments, and the lower part is 50 to 80

percent rock fragments.

The Bir horizon has hue of 10YR to 5YR, value of 3 to 5 when

moist and 4 to 6 when dry, and chroma of 3 to 8 when moist

or dry. It is gravelly loam, gravelly sandy loam, very gravelly

loam, very gravelly fine sandy loam, or very gravelly sandy loam.

The IIC horizon has hue of 5Y to 10YR, value of 3 to 6

when moist and 3 to 7 when dry, and chroma of 2 to 4

when moist and 3 to 6 when dry. It is extremely gravelly

coarse sand to very gravelly loamy sand.

Snohomish series

The Snohomish series consists of very deep, poorly drained

soils on flood plains. These soils formed in alluvium

underlain by peat and muck. Slope is 0 to 2 percent.

Elevation ranges from near sea level to 150 feet. The

average annual precipitation is about 40 inches, the average

annual air temperature is about 50 degrees F, and the average

frost-free season is 180 to 200 days.

Typical pedon of Snohomish silt loam, 1,500 feet west

and 1,250 feet south of the northeast corner of sec. 22, T.

29 N., R. 5 E.

Ap-0 to 6 inches; very dark grayish brown (10YR 3/2) silt loam,

light brownish gray (10YR 6/2) dry; moderate fine

granular structure; slightly hard, friable, nonsticky and

slightly plastic; many fine and medium roots; many fine and

medium interstitial pores; very strongly acid; abrupt smooth

boundary.

B21g-6 to 14 inches; gray (5Y 6/1) silty clay loam, gray (5Y

6/1) dry; many fine, medium, and coarse prominent dark

olive (5Y 3/3) and dark reddish brown (2.5YR 3/4)

mottles on peds, pale olive (5Y 6/4) and reddish brown

(5YR 4/4) dry; weak fine and medium subangular blocky

structure parting to weak fine granular; slightly hard, friable,

slightly

sticky and slightly plastic; many fine and medium

roots; few fine tubular pores and common very fine

tubular pores; very strongly acid; clear wavy boundary.

B22g-14 to 29 inches; very dark grayish brown (2.5Y 3/2)

silty clay loam, light brownish gray (10YR 6/2) dry;

many fine distinct black (10YR 2/1), gray (N 6/0), and

dark reddish brown (5YR 3/2) mottles, very dark gray

(10YR 3/1) and dark brown (7.5YR 4/4) dry; weak coarse

and medium platy structure parting to weak fine

subangular blocky; hard, friable, slightly sticky and

plastic; common fine roots; common fine tubular pores;

very strongly acid; clear smooth boundary.

IIOe1-29 to 36 inches; dark reddish brown (5YR 2/2, on

broken face and rubbed) hemic material; about 65

percent fibers, about 20 percent when rubbed; weak

medium platy structure; slightly hard, friable, nonsticky and

slightly plastic; 3 percent woody fragments; very

strongly acid; abrupt smooth boundary.

IIOe2-36 to 44 inches; very dark grayish brown (10YR

3/2, on broken face and rubbed) hemic material; about

50 percent fibers, 15 percent when rubbed; massive;

hard, friable, nonsticky and slightly plastic; 2 percent

woody fragments 1 /4 to 1 inch in diameter; medium

acid; gradual smooth boundary.

llOe3-44 to 60 inches; very dark gray (10YR 3/1, rubbed)

and very dark grayish brown (10YR 3/2, rubbed) hemic

material, gray (10YR 6/1, on broken face and rubbed)

dry; about 60 percent fibers, about 20 percent when

rubbed; massive; hard, friable, nonsticky and slightly

plastic; 2 percent woody fragments 1 /4 to 1 inch in

diameter; medium acid.

The profile is 0 to 10 percent coarse fragments.

The A horizon has hue of 10YR or 2.5Y, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 1 or 2

when moist or dry. The Bg horizon has hue of 10YR, 5YR,

5Y, or 2.5Y, value of 3 to 6 when moist and 3 to 7 when

dry, and chroma of 1 or 2 when moist or dry. It is silty clay

loam or silty clay.

Depth to the Oe horizon is 17 to 32 inches. This

horizon is stratified, sedimentary, and woody, and it

consists of sedges or peat with thin lenses of silty clay

loam.

The Snohomish soils in this survey are a taxadjunct to the

Snohomish series because they show evidence of volcanic

ash in the upper part. This difference does not affect the

use and management of the soils.

Sulsavar series

The Sulsavar series consists of very deep, well drained

soils on terraces and alluvial fans. These soils formed in

volcanic ash and alluvium. Slope is 0 to 8 percent.

Elevation is 400 to 1,200 feet. The average annual

precipitation is about 60 inches, the average
annual air temperature is about 46 degrees F, and the

average frost-free season is 120 to 180 days.

Typical pedon of Sulsavar gravelly loam, 0 to 8

percent slopes, 1,500 feet south and 2,700 feet west of the

northeast corner of sec. 25, T. 29 N., R. 7 E.

O1-1 /2 inch to 0; leaves, needles, twigs, and mosses.

A1-0 to 3 inches; dark brown (10YR 3/3) gravelly loam,

yellowish brown (10YR 5/4) dry; weak fine

granular structure; slightly hard, friable, nonsticky and

slightly plastic; common fine roots; common fine

tubular pores; 25 percent rounded pebbles; medium acid;

abrupt smooth boundary.

B21-3 to 13 inches; dark brown (10YR 4/3) gravelly

sandy loam, pale brown (10YR 6/3) dry; weak

medium subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few fine

roots; common fine and medium tubular pores; 25

percent rounded pebbles; micaceous; medium acid;

abrupt smooth boundary.

B22-13 to 18 inches; yellowish brown (10YR 5/4) silt

loam, very pale brown (10YR 7/3) dry; weak coarse

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; few fine

roots; common medium tubular pores and very few

coarse tubular pores; 10 percent rounded pebbles;

micaceous; slightly acid; abrupt smooth boundary.

B23-18 to 24 inches; yellowish brown (10YR 5/4) gravelly

loam, light yellowish brown (10YR 6/4) dry; massive;

slightly hard, friable, slightly sticky and slightly plastic; few

fine roots; few fine tubular pores; 30 percent rounded

pebbles; micaceous; slightly acid; abrupt smooth boundary.

B3-24 to 33 inches; yellowish brown (10YR 5/4) gravelly

loam, pale brown (10YR 6/3) dry; massive; slightly

hard, friable, slightly sticky and slightly plastic; few fine

roots; few fine tubular pores; 30 percent rounded

pebbles; very micaceous; slightly acid; abrupt smooth

boundary.

C1-33 to 38 inches; dark brown (10YR 4/3) sandy

loam, pale yellow (2.5Y 7/4) dry; massive;

slightly hard, friable, nonsticky and nonplastic; few

fine roots; few fine tubular pores; 10 percent

pebbles; micaceous; neutral; abrupt smooth

boundary.

C2-38 to 60 inches; brown (10YR 5/3) stratified very gravelly

loamy sand and gravelly sandy loam, pale brown (10YR

6/3) dry; single grain; loose; 50 percent pebbles in

loamy sand strata and 20 percent pebbles in sandy

loam strata; neutral.

The mean annual soil temperature at a depth of 20

inches is 47 to 50 degrees F. The control section is 15 to

35 percent coarse fragments.

The A1 horizon has hue of 10YR or 7.5YR, value of 2 to

4 when moist and 3 to 6 when dry, and chroma of 2 to 5

when moist or dry.

The B horizon has hue of 10YR or 7.5YR and chroma of 3 to 6

when moist or dry. It is stratified with individual

layers of gravelly loam, gravelly fine sandy loam,

gravelly sandy loam, or gravelly silt loam.

The C horizon has hue of 10YR, 5Y, or 2.5Y, value of 4 or

5 when moist and 5 to 7 when dry, and chroma of 2 to 5

when moist or dry. It is stratified with individual layers of very

gravelly loamy sand to loam.

Sultan series

The Sultan series consists of very deep, moderately well

drained soils on flood plains. These soils formed in

alluvium. Slope is 0 to 2 percent. Elevation is 10 to 120

feet. The average annual precipitation is about 45 inches,

the average annual air temperature is about 49 degrees F,

and the average frost-free season is 150 to 200 days.

Typical pedon of Sultan silt loam, 500 feet south and 50

feet east of the north quarter corner of sec. 24, T. 28 N., R.

5 E.

Ap-0 to 12 inches; dark grayish brown (10YR 4/2) silt

loam, light brownish gray (10YR 6/2) dry; moderate

medium subangular blocky structure; hard, friable, slightly

sticky and plastic; common fine roots; common fine

tubular pores and few medium tubular pores; neutral;

clear smooth boundary.

C1-12 to 28 inches; dark grayish brown (2.5Y 4/2) silty

clay loam, light brownish gray (2.5Y 6/2) dry; weak

moderate subangular blocky structure; hard, friable,

slightly sticky and plastic; few fine roots; few very fine,

fine, and coarse tubular pores; neutral; gradual

smooth boundary.

C2-28 to 42 inches; dark grayish brown (2.5Y 4/2) silty

clay loam, light brownish gray (2.5Y 6/2) dry; very few

fine faint mottles; massive; slightly hard, very friable,

nonsticky and slightly plastic; few medium roots;

common fine and medium pores; finely stratified with

lenses of loamy fine sand 1/4 inch thick; neutral; gradual

smooth boundary.

C3g-42 to 60 inches; olive brown (2.5Y 4/4) fine sandy

loam, light brownish gray (2.5Y 6/2) dry; few fine faint

light olive brown (2.5Y 5/4) mottles; massive; soft, very

friable, nonsticky and nonplastic; many very fine

interstitial pores; finely stratified with strata of loamy fine

sand 1/2 to 1 inch thick; neutral.

The control section is less than 5 percent coarse

fragments, less than 15 percent fine and coarse sand,

and 20 to 35 percent clay.

The A horizon has value of 3 or 4 when moist and 4 to 6

when dry. The C horizon has hue of 2.5Y and 5Y, value of 4

or 5 when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist or dry. The lower part is stratified with loamy

very fine sand or sand, or both.

Sultan Variant

Sultan Variant consists of very deep, well drained soils on

flood plains. These soils formed in alluvium. Slope is
0 to 3 percent. Elevation is 40 to 400 feet. The average

annual precipitation is about 55 inches, the average

annual air temperature is about 49 degrees F, and the

average frost-free season is 150 to 200 days.

Typical pedon of Sultan Variant silt loam, 1,500 feet

north and 400 feet east of the southwest corner of sec. 35,

T. 28 N., R. 8 E.

Ap-0 to 9 inches; very dark grayish brown (10YR 3/2) silt

loam, grayish brown (2.5Y 5/2) dry; weak coarse

granular structure; slightly hard, friable, slightly sticky

and slightly plastic; common very fine and fine roots;

medium acid; abrupt smooth boundary.

B21-9 to 18 inches; dark grayish brown (2.5Y 4/2) very

fine sandy loam, light brownish gray (2.5Y 6/2) dry; weak

coarse subangular blocky structure; soft, friable, slightly

sticky and slightly plastic; discontinuous strata of loamy

very fine sand 1/2 to 1 inch thick throughout horizon;

common very fine and fine roots and few medium and

coarse roots; medium acid; clear smooth boundary.

B22-18 to 25 inches; olive brown (2.5Y 4/4) silt loam, light

brownish gray (2.5Y 6/2) dry; common fine faint grayish

brown and light olive brown (2.5Y 5/2 and 5/6) mottles;

weak coarse subangular blocky structure; soft, friable,

slightly sticky and slightly plastic; common very fine and

fine roots; medium acid; abrupt smooth boundary.

IIC1-25 to 34 inches; olive brown (2.5Y 4/4) loamy fine

sand, light brownish gray (2.5Y 6/2) dry; massive; soft,

very friable, nonsticky and nonplastic; few very fine

and fine roots; medium acid; abrupt smooth boundary.

IIC2-34 to 40 inches; olive gray (5Y 5/2) sand, light

brownish gray (2.5Y 6/2) dry; single grain; loose;

slightly acid; abrupt smooth boundary.

IIC3-40 to 50 inches; olive gray (5Y 5/2) coarse sand,

multicolored dry; single grain; loose; slightly acid; abrupt

smooth boundary.

IIC4-50 to 60 inches; multicolored very gravelly coarse

sand; single grain; loose; 40 percent pebbles; slightly acid.

The mean annual soil temperature at a depth of 20

inches is 47 to 52 degrees F. Depth to loamy fine sand,

sand, or very gravelly sand is 20 to 32 inches.

The A horizon has hue of 10YR, 5Y, or 2.5Y, value of 2 to 4

when moist and 4 to 6 when dry, and chroma of 2 or 3 when

moist or dry.

The B horizon has hue of 5Y or 2.5Y, value of 2 to 4

when moist and 4 to 6 when dry, and chroma of 1 or 2

when moist or dry. It is stratified with individual layers of

loamy fine sand to silt loam.

The IIC horizon has hue of 2.5Y or 5Y, value of 4 to 7

when moist or dry, and chroma of 2 to 4 when moist or dry.

The lower part is 35 to 55 percent coarse fragments.

Sumas series

The Sumas series consists of very deep, poorly

drained soils on flood plains. These soils formed in

alluvium. Slope is 0 to 3 percent. Elevation is 10 to 500

feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and the average frost-free season is 170 to 210

days.

Typical pedon of Sumas silt loam, 1,375 feet north and 62

feet west of the southeast corner of sec. 25, T. 28 N., R. 5

E.

Ap-0 to 8 inches; dark grayish brown (2.5Y 4/2) silt loam,

light brownish gray (2.5Y 6/2) dry; weak medium granular

structure; slightly hard, friable, slightly sticky and slightly

plastic; common fine and medium roots; few fine

tubular pores; neutral; abrupt smooth boundary.

A12-8 to 14 inches; dark grayish brown (2.5Y 4/2) silt

loam, light brownish gray (2.5Y 6/2) dry; weak medium

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; few fine roots; few fine

tubular pores; slightly acid; abrupt smooth boundary.

C1g-14 to 21 inches; grayish brown (2.5Y 5/2) silt loam, light

brownish gray (2.5Y 6/2) dry; many fine and medium

distinct olive brown (2.5Y 4/4) and olive gray (5Y 5/2)

mottles, light olive brown (2.5Y 5/4) and light olive gray

(5Y 6/2) dry; weak medium subangular blocky structure;

slightly hard, friable, slightly sticky and slightly plastic; few

fine roots; very few fine tubular pores; slightly acid;

abrupt smooth boundary.

C2g-21 to 24 inches; olive gray (5Y 5/2) fine sandy loam,

light olive gray (5Y 6/2) dry; many medium and fine

distinct olive brown (2.5Y 4/4) mottles; massive; slightly

hard, very friable, nonsticky and nonplastic; very few fine

tubular pores; neutral; clear smooth boundary.

IIC3-24 to 60 inches; pale yellow (2.5Y 7/4), olive brown

(2.5Y 4/4), and very dark grayish brown (2.5Y 3/2)

sand, pale yellow (2.5Y 7/3), light yellowish brown

(2.5Y 6/4), and dark grayish brown (2.5Y 4/2) dry;

single grain; loose; many fine interstitial pores; 5 percent

fine pebbles; neutral.

The mean annual soil temperature at a depth of 20 inches

is 48 to 52 degrees F. Sand or gravelly sand is at a depth of

20 to 32 inches. The upper part of the control section is 10

to 18 percent clay and less than 15 percent fine sand or

coarser material. The lower part is sand or gravelly sand.

The A horizon has hue of 2.5Y, 5Y, or 10YR, value of 2 to 4

when moist and 4 to 6 when dry, and chroma of 2 or 3

when moist or dry.

The C1g horizon has value of 2 to 5 when moist and 4 to

6 when dry, and it has chroma of 1 or 2 when moist
or dry. It is fine sandy loam or silt loam and has fine and

medium distinct mottles.

The IIC horizon has hue of 2.5Y or 5Y, value of 3 to 7

when moist or dry, and chroma of 2 to 4 when moist or dry. It is

loamy sand to gravelly sand.

The Sumas soils in this survey area are a taxadjunct to

the Sumas series because the upper part of the control

section averages less than 18 percent clay. This difference

does not affect the use and management of the soils.

Tokul series

The Tokul series consists of moderately deep,

moderately well drained soils on till plains. These soils

formed in glacial till and volcanic ash. Slope is 0 to 25

percent. Elevation is 200 to 800 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 46 degrees F, and the average

frost-free season is 140 to 200 days.

Typical pedon of Tokul gravelly loam, 0 to 8 percent

slopes, 2,200 feet east and 1,050 feet north of the

southwest corner of sec. 6, T. 28 N., R. 7 E. (fig. 6).

O1-1 1/2 inches to 1/2 inch; forest litter of leaves and twigs.

O2-1/2 inch to 0; black (10YR 2/1) decomposed litter.

A1-0 to 3 1/2 inches; dark brown (7.5YR 3/2) gravelly

loam, yellowish brown (10YR 5/4) dry; moderate medium

granular structure; soft, very friable, .slightly sticky and

nonplastic; common very fine, fine, and medium roots

and few coarse roots; common very fine discontinuous

pores; 5 percent medium rounded concretions and 15

percent pebbles; medium acid; abrupt wavy boundary.

B21-3 1/2 to 7 inches; dark brown (7.5YR 4/4) gravelly

loam, light brown (7.5YR 6/4) dry; weak medium

subangular blocky structure; slightly hard, very friable, slightly

sticky and slightly plastic; weakly smeary; common very

fine, fine, and medium roots and few coarse roots;

common very fine discontinuous pores; 5 percent fine

and medium rounded concretions and 15 percent

pebbles; slightly acid; clear smooth boundary.

B22-7 to 15 inches; strong brown (7.5YR 5/6) gravelly

loam, light yellowish brown (10YR 6/4) dry; weak medium

subangular blocky structure; slightly hard, very friable,

slightly sticky and slightly plastic; weakly smeary;

common very fine, fine, and medium roots and few

coarse roots; common very fine discontinuous pores; 5

percent fine rounded concretions and 15 percent

pebbles; medium acid; clear wavy boundary.

B3-15 to 22 inches; dark yellowish brown (10YR 4/4)

gravelly loam, very pale brown (10YR 7/4) dry;

common medium distinct yellowish brown (10YR 5/8)

mottles; weak medium subangular blocky structure;

slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; few very fine, fine,

Figure 6.-Typical profile of Tokul gravely loam, 0 to 8

percent slopes.

medium, and coarse roots; common very fine

discontinuous pores; 3 percent fine rounded

concretions, 10 percent cobbles, and 20 percent

pebbles; slightly acid; clear smooth boundary.

C1-22 to 31 inches; light olive brown (2.5Y 5/4) gravelly

fine sandy loam, pale yellow (2.5Y 8/4) dry;
common fine distinct yellowish brown (10YR 5/8)

mottles; massive; slightly hard, friable, slightly sticky and

nonplastic; very weakly smeary; few very fine, fine,

medium, and coarse roots; common very fine

discontinuous pores; 1 percent fine irregularly shaped

concretions, 5 percent cobbles, and 25 percent

pebbles; medium acid; abrupt smooth boundary.

IIC2sim-31 to 60 inches; weakly cemented duripan that

breaks to dark grayish brown (2.5Y 4/2) gravelly sandy

loam, light gray (2.5Y 7/2) dry; common medium distinct

yellowish brown (10YR 5/8) mottles; massive; hard,

extremely firm; extremely hard in places; 35 percent

pebbles; a very thin discontinuous silica layer (1/2

millimeter thick) on surface of horizon; medium acid.

The mean annual soil temperature at a depth of 20

inches is 47 to 50 degrees F. The duripan is at a depth of

20 to 40 inches. The control section is more than 15

percent to less than 35 percent rock fragments.

The A horizon has value of 2 to 4 when moist and 4 or 5

when dry, and it has chroma of 1 to 4 when moist or dry.

The B horizon has value of 4 to 6 when moist and 5 to 7

when dry, and it has chroma of 4 to 6 when moist or dry. It

is gravelly loam, gravelly silt loam, or gravelly sandy loam,

and is 5 percent or less concretions.

The C horizon has hue of 2.5Y or 5Y, value of 4 to 6 when

moist and 5 to 8 when dry, and it has chroma of 2 to 4 when

moist or dry. It is gravelly loamy sand, gravelly fine sandy

loam, or gravelly loam.

Verlot series

The Verlot series consists of moderately deep, moderately

well drained soils on mountainsides and ridgetops. These soils

formed in glacial till and volcanic ash. Slope is 3 to 25

percent. Elevation is 2,800 to 4,000 feet. The average

annual precipitation is about 90 inches, the average annual

air temperature is about 41 degrees F, and the average

frost-free season is 90 to 100 days.

Typical pedon of Verlot mucky silt loam, 3 to 25 percent

slopes, about 12 miles east of Arlington, 2,200 feet west

and 180 feet south of the northeast corner of sec. 35, T.

32 N., R. 7 E. (fig. 7).

O1-1 1/2 inches to 0; partially decomposed leaves, twigs, and

needles; abrupt smooth boundary.

A1-0 to 10 inches; black (10YR 2/1) mucky silt loam, very

dark grayish brown (10YR 3/2) dry; weak fine subangular

blocky structure; slightly hard, very friable, slightly sticky

and slightly plastic; weakly smeary; common fine and

medium roots; many fine interstitial pores; strongly acid;

abrupt wavy boundary.

A2-10 to 16 inches; brown (10YR 5/3) silt loam, pale brown

(10YR 6/3) dry; black (10YR 2/1) organic

Figure 7.-Typical profile of Verlot mucky silt loam, 3 to

25 percent slopes.

coatings on peds, dark grayish brown (10YR 4/2) dry;

weak medium subangular blocky structure; slightly

hard, friable, slightly sticky and slightly plastic; weakly

smeary; common fine and medium roots; few fine

tubular pores; strongly acid; abrupt wavy boundary.

B21hir-16 to 21 inches; reddish brown (5YR 4/4) silt loam, light

reddish brown (5YR 6/4) dry; black (5YR 2/1) organic

coatings on peds, dark reddish gray (5YR 4/2) dry;

common fine and medium faint yellowish red (5YR 4/6)

mottles; moderate medium subangular blocky

structure; slightly hard, friable, slightly sticky and

slightly plastic; weakly smeary; few fine and medium

roots; 5 percent rounded
granitic pebbles and 5 percent concretions; strongly

acid; gradual wavy boundary.

B22hir-21 to 26 inches; dark brown (7.5YR 4/4) gravelly

loam, light brown (7.5YR 6/4) dry; common fine distinct

dark reddish brown (5YR 3/3) mottles, reddish brown

(5YR 5/3) dry; weak medium subangular blocky

structure; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; few fine and medium roots; 20

percent pebbles; strongly acid; gradual wavy boundary.

B23-26 to 30 inches; dark brown (10YR 4/3) gravelly loam,

pale brown (10YR 6/3) dry; common medium distinct

dark reddish brown (5YR 3/2) mottles, reddish gray

(5YR 5/2) dry; massive; slightly hard, friable, slightly

sticky and slightly plastic; weakly smeary; few fine and

medium roots; 20 percent pebbles; strongly acid; gradual

wavy boundary.

B3-30 to 35 inches; dark brown (10YR 4/3) gravelly loam, pale

brown (10YR 6/3) dry; many medium distinct very dusky

red (2.5YR 2/2) mottles, dusky red (2.5YR 3/2) dry;

massive; slightly hard, friable, slightly sticky and slightly

plastic; weakly smeary; few fine roots matted on top of the

dense till; few fine tubular pores; 20 percent pebbles;

strongly acid; abrupt smooth boundary.

IICr-35 to 60 inches; olive brown (2.5Y 4/4) and dark

grayish brown (2.5Y 4/2) dense glacial till that breaks to

gravelly loamy sand, light yellowish brown (2.5Y 6/4) and

light brownish gray (2.5Y 6/2) dry; massive; hard, firm,

nonsticky and nonplastic; 20 percent pebbles; strongly acid.

Thickness of the solum and depth to the dense glacial till

are 20 to 40 inches. The mean annual soil temperature at a

depth of 20 inches is 41 to 43 degrees F. The control

section is 5 to 25 percent coarse fragments.

The A1 horizon has hue of 5YR, 7.5YR, or 10YR, and it

has value of 2 or 3 when moist and 3 to 5 when dry. The A2

horizon has hue of 7.5YR or 10YR, value of 5 or 6 when

moist and 6 or 7 when dry, and chroma of 2 or 3 when moist

or dry.

The B horizon has value of 3 to 6 when moist and 4 to 7

when dry, and it has chroma of 2 to 4 when moist or dry.

The upper part of the horizon is loam or silt loam, and the

lower part is gravelly loam or gravelly sandy loam.

The IICr horizon has hue of 2.5Y to 7.5YR, value of 4 or 5

when moist and 5 or 6 when dry, and chroma of 2 to 4

when moist or dry. It is dense glacial till that breaks down

to gravelly loamy sand or gravelly sandy loam.

Winston series

The Winston series consists of very deep, somewhat

excessively drained soils on terraces, terrace escarpments,

and outwash plains. These soils formed in glacial

outwash or old alluvium and volcanic ash. Slope

is 0 to 30 percent. Elevation is 200 to 900 feet. The

average annual precipitation is about 55 inches, the

average annual air temperature is about 48 degrees F, and the

average frost-free season is 140 to 200 days.

Typical pedon of Winston gravelly loam, 0 to 3 percent

slopes, 1,200 feet west and 1,250 feet north of the

southeast corner of sec. 3, T. 28 N., R. 7 E.

O1-2 inches to 1/2 inch; partially decomposed needles, leaves,

and twigs.

O2-1/2 inch to 0; black (10YR 2/1) decomposed litter.

A1-0 to 2 1/2 inches; dark brown (7.5YR 3/2) gravelly

loam, dark grayish brown (10YR 4/2) dry; moderate fine

granular structure; soft, very friable, slightly sticky and

nonplastic; weakly smeary; common very fine, fine,

medium, and coarse roots; common very fine vesicular

pores and few very fine discontinuous tubular pores;

20 percent rounded pebbles; strongly acid; abrupt smooth

boundary.

B21-2 1/2 to 7 inches; dark brown (7.5YR 4/3) gravelly

loam, yellowish brown (10YR 5/6) dry; weak fine

subangular blocky structure; soft, very friable, slightly sticky

and nonplastic; weakly smeary; common very fine,

fine, and medium roots and few coarse roots; few very

fine discontinuous pores; 20 percent rounded pebbles;

slightly acid; clear smooth boundary.

B22-7 to 10 inches; strong brown (7.5YR 5/6) gravelly

loam, brownish yellow (10YR 6/6) dry; weak coarse

subangular blocky structure; soft, friable, slightly sticky and

nonplastic; weakly smeary; common very fine and fine

roots and few medium and coarse roots; few very fine

discontinuous pores; 20 percent rounded pebbles;

slightly acid; clear wavy boundary.

B3-10 to 16 inches; yellowish brown (10YR 5/6) gravelly

fine sandy loam, brownish yellow (10YR 6/6) dry; weak

medium subangular blocky structure; soft, very friable,

slightly sticky and nonplastic; weakly smeary; common

very fine and fine roots and few medium and coarse

roots; few very fine discontinuous pores; 25 percent

rounded pebbles; slightly acid; clear wavy boundary.

C1-16 to 25 inches; yellowish brown (10YR 5/4) gravelly

fine sandy loam, light yellowish brown (10YR 6/4) dry;

massive; soft, friable, slightly sticky and nonplastic;

weakly smeary; few very fine, fine, medium, and coarse

roots; common very fine discontinuous pores; 30

percent rounded pebbles; slightly acid; abrupt wavy

boundary.

IIC2-25 to 60 inches; very dark grayish brown (2.5Y 3/2)

extremely gravelly coarse sand, light brownish gray

(2.5Y 6/2) dry; single grain; loose; few fine and medium

roots to a depth of about 30 inches; 80 percent rounded

pebbles; slightly acid.

The solum is 15 to 30 inches thick. The mean annual

soil temperature at a depth of 20 inches is 47 to 50
degrees F. The upper part of the 10- to 40-inch control

section is 15 to 35 percent rock fragments, and the lower

part is 35 to 60 percent rock fragments.

The A horizon has value of 2 or 3 when moist and 3 or 4

when dry, and it has chroma of 1 or 2 when moist or dry.

The B horizon has hue of 5YR, 7.5YR, or 10YR. It is

gravelly sandy loam, gravelly fine sandy loam, or gravelly loam.

The IIC horizon has hue of 10YR, 2.5Y, or 5Y, value of 3

to 6 when moist and 3 to 7 when dry, and chroma of 2 to 6

when moist or dry. It is very gravelly loamy coarse sand,

extremely gravelly coarse sand, very gravelly sand, or extremely

gravelly sand.
formation of the soils

Soil is a result of the interaction of soil-forming processes

on material deposited by geologic agents (15). The

properties of the soil at any given place are determined by

five factors: (1) the physical and mineralogical composition

of the parent material, (2) the climate under which the soil

material accumulated and existed, (3) the living organisms

on and in the soil, (4) topography, and (5) the length of time

the forces of soil formation have acted on the soil material.

These factors, as they occur in the survey area, are

described in this section.

parent material

Parent material is the unconsolidated and mostly

chemically weathered mineral or organic matter from

which soil is formed. Most of the soils in Snohomish County

Area formed in deposits of glacial drift laid down during the

Vashon Period of the Fraser Glaciation, late in the

Pleistocene (11). The major kinds of material deposited by

the glacier are till, outwash, and some material mixed

with volcanic ash.

Vashon Till is of very dense, consolidated lodgment till

with a mantle of ablation till. The Alderwood soil is an

example of the soils that formed in this material. Very poorly

drained, depressional areas occur in the glacial till, and

organic material from surrounding wet, mineral soils

accumulates in these areas. The Mukilteo and Orcas soils

are examples of these organic soils.

As the Vashon Glacier melted, large quantities of melt

water sorted material in its path, leaving very gravelly and

sandy sediment. The Indianola, Custer, Everett, and Lynnwood

soils are examples of soils that formed in this glacial

outwash. Some of the melt water was dammed, resulting in

the deposition of lacustrine material that extends from the

valleys to the foot slopes of the mountains. The Bellingham,

Kitsap, Pastik, and Rober soils formed in this material.

Alluvium, mostly silty alluvium mixed with volcanic ash,

accumulated in the major valleys in postglacial times. The

Puget, Puyallup, Snohomish, and Sultan soils are examples of

soils that formed in these accumulations of alluvium.

On the mountainsides and plateaus in the area are

colluvium and residuum derived from andesite and basalt

and influenced by a thin mantle of volcanic ash. The Hartnit

and Olomount soils are examples of moderately deep

soils that formed in colluvium and residuum.

topography

Topography or relief affects soil formation by

influencing the drainage pattern and runoff of the soil

surface and the internal drainage in the soil profile.

Level or nearly level soils receive more effective

precipitation than steeper soils. In contrast to the steeper

soils, therefore, the more nearly level soils are leached of

more minerals and organic matter and commonly are

leached and weathered to a greater depth. They show

more development in the profile, particularly a thicker,

darker, and redder B horizon.

Topography also influences soil formation and soil

characteristics by concentrating water in depressional areas

and at the toe of slopes. Most of the poorly drained upland

soils, including the Bellingham, McKenna, and Mukilteo soils,

are in this type of topographic position.

Aspect can also influence soil characteristics. Soils on

steep, north-facing slopes generally receive more effective

precipitation than soils on south-facing slopes. This is

because less solar energy reaches the north-facing slopes,

which reduces the evaporation of water from the soil.

living organisms

Plants, micro-organisms, earthworms, insects, fungi, and

other forms of life are active in soil-forming processes.

They contribute organic matter and nitrogen to the soil

material, help to decompose plant residue, and affect soil

reaction.

Plant life in the survey area probably has had a greater

effect on soil formation than have animals. Some soils, such

as the Hartnit and Lynnwood soils, developed predominantly

under conifers and typically have a thin, dark-colored surface

layer and a distinct subsurface layer. Other soils, such as

the Norma and McKenna soils, formed under mixed stands

of trees and commonly have a darker and thicker surface

layer and do not have a subsurface layer. Soils that formed

under sedges, rushes, and grasses in open areas of valley

bottoms have a thick, very dark brown or black surface

layer. The Snohomish soils are an example.

Earthworms, insects, and micro-organisms help to

convert organic compounds and other soil elements into

forms suitable for plant use, and they aid in soil aeration.

Burrowing animals, such as moles and mice, add organic
material to the soil and bring nutrients from the subsoil to

the surface; the nutrients replace those that have been

leached from the surface layer or have been used by the

plants. These animals also help improve soil drainage and

aeration.

climate

Precipitation and temperature are the main climatic factors

that have influenced soil formation in the survey area.

Three distinct climatic zones are in the area. The first is

the western part of the area, which ranges from near sea

level to an elevation of about 800 feet. The average annual

precipitation in this zone is 30 to 60 inches, the average

frost-free period is 160 to 210 days, and the mean annual air

temperature is about 50 degrees F. The second is in the

middle part of the area, which ranges from 800 to 1,800

feet in elevation. The average annual precipitation in this

part is 60 to 80 inches, the average frost-free period is 140

to 160 days, and the mean annual air temperature is about 45

degrees F. The third is in the eastern part of the area,

which has an elevation of more than 1,800 feet. The

average annual precipitation in this part is 80 inches or

more, the average frost-free period is 90 to 140 days, and

the mean annual air temperature is about 42 degrees F.

Soils on uplands in the western part of the area have a

weakly developed subsurface layer, and soils in the eastern

part have a distinct subsurface layer. The

Alderwood soils in the western part and the Potchub soils in

the eastern part are examples. The Olomount, Oso, and

Verlot soils, on uplands in the eastern part of the survey

area, are more acid and are leached of bases more than the

Alderwood, Cathcart, and Ogarty soils in the western part.

Also, the Everett and Tokul soils in the western part have a

warmer temperature and a thinner organic surface layer

than the Potchub and Verlot soils.

Additional information on climate of the area is given

under "Climate" in the section "General nature of the

survey area."

time

Time is necessary for the formation of soils and their

horizons. Most of the soils in the survey area do not have a

strongly expressed subsoil. Old soils commonly have more

strongly expressed horizons than young soils.

In this area soil-forming processes have been acting on

parent material since the glaciation, or about 12,000 years.

Alluvium has periodically accumulated in the stream valleys,

and soils such as the Norma, Pilchuck, and Puyallup soils

formed. Soils that formed on the uplands have a darkcolored surface layer and subsoil and are redder in color

than the parent material. Everett and Winston soils are

examples.

The texture of parent material is an important factor in soil

formation. Soils that form in sandy material develop

structure more slowly than do soils that form in clayey

material.
references

(1) American Association of State Highway [and

Transportation] Officials. 1970. Standard specifications

for highway materials and methods of sampling and

testing. Ed. 10, 2 vol., illus.

(2) American Society for Testing and Materials. 1974. Method

for classification of soils for engineering purposes.

ASTM Stand. D 2487-69. In 1974 Annual Book of

ASTM Standards, Part 19, 464 pp., illus.

(3) Anderson, A. C. 1947. Soil survey of Snohomish County,

Washington. U.S. Dep. Agric. 76 pp., illus.

(4) Barnes, George H. 1962. Yield of even-aged stands of

western hemlock. U.S. Dept. Agric. Techn. Bull. 1273.

(5) Bassett, Patricia M. and Grover A. Choate. 1974. Timber

resource statistics for Washington. U.S. Dep. Agric., Forest

Serv. Res. Bull. PNW-53, 33 pp.

(6) Brady, Roy C. 1978. Forest products directory for the state

of Washington. State of Wash. Dep. Nat. Resour.,

164 pp.

(7) Chambers, Charles J. 1974. Empirical yield tables for

predominantly alder stands in Western Washington. State

of Wash. Dep. Nat. Resour. Rep. No. 31, 70 pp.

(8) Chambers, Charles J. and Franklin M. Wilson. 1972.

Empirical yield tables for the Douglas-fir zone.

State of Wash. Dep. Nat. Resour. Rep. No. 20R, 16 pp.

(9) Chambers, Charles J. and Franklin M. Wilson. 1978.

Empirical yield tables for the western hemlock zone.

State of Wash. Dep. Nat. Resour. Rep. No. 22R, 12

PP.

(10) Cline, Marlin G. 1949. Basic principles of soil

classification. Soil Sci. 67: 81-91.

(11) Crandell, Dwight R., P. R. Mullineaux, and H. H. Waldron.

1965. Age and origin of the Puget Sound Trough in Western

Washington. U.S. Geol. Surv. Prof. Pap.

(12) King, James E. 1966. Site index curves for Douglas-fir in the

Pacific Northwest. Forestry Pap. No. 8., Weyerhauser

Co., 49 pp., illus.

(13) McArdle, R. E., W. H. Meyer, and D. Bruce. 1961. The

yield of Douglas-fir in the Pacific Northwest. U.S.

Dep. Agric. Tech. Bull. 201, 74 pp., illus.

(14) Portland Cement Association. 1962. PCA soil primer. 52 pp.,

illus.

(15) Simonson, Roy W. 1959. Outline of a generalized theory

of soil genesis. Soil Sci. Soc. Am. Proc. 23: 152-

156, illus.

(16) Snohomish County. 1971. General land use plan, technical

supplement. Land Use Manual Tech. Rep. No. 3, 24 pp.,

illus.

(17) United States Department of Agriculture. 1951. Soil survey

manual. U.S. Dep. Agric. Handb. 18, 503 pp., illus.

[Supplements replacing pp. 173-188 issued May 1962]

(18) United States Department of Agriculture. 1961. Land

capability classification. U.S. Dep. Agric. Handb. 210, 21

pp.

(19) United States Department of Agriculture. 1975. Soil

taxonomy: A basic system of soil classification for

making and interpreting soil surveys. Soil Conserv. Serv.,

U.S. Dep. Agric. Handb. 436, 754 pp., illus.

(20) Washington Conservation Needs Committee. 1970.

Washington soil and water conservation needs

inventory. U.S. Dep. Agric., Soil Conserv. Serv., 249 pp.,

illus.

(21) Wiley, Kenneth. 1978. Site index tables for western hemlock

in the Pacific Northwest. Forestry Pap. No. 17.,

Weyerhaeuser Co., 22 pp.

(22) Worthington, Norman P., Floyd A. Johnson, George R.

Staebler, and William J. Lloyd. 1960. Normal yield

tables for red alder. U.S. Dep. Agric. Res. Pap. 36, 29 pp.
glossary

ABC soil. A soil having an A, a B, and a C horizon.

Ablation till. Loose, permeable till deposited during the final

downwasting of glacial ice. Lenses of crudely sorted

sand and gravel are common.

AC soil. A soil having only an A and a C horizon.

Commonly such soil formed in recent alluvium or on steep

rocky slopes.

Aeration, soil. The exchange of air in soil with air from the

atmosphere. The air in a well aerated soil is similar to

that in the atmosphere; the air in a poorly aerated soil is

considerably higher in carbon dioxide and lower in

oxygen.

Aggregate, soil. Many fine particles held in a single mass

or cluster. Natural soil aggregates, such as granules,

blocks, or prisms, are called peds. Clods are aggregates

produced by tillage or logging.

Alluvium. Material, such as sand, silt, or clay, deposited on

land by streams.

Area reclaim (in tables). An area difficult to reclaim after the

removal of soil for construction and other uses.

Revegetation and erosion control are extremely difficult.

Available water capacity (available moisture capacity). The

capacity of soils to hold water available for use by most

plants. It is commonly defined as the difference between

the amount of soil water at field moisture capacity and

the amount at wilting point. It is commonly expressed

as inches of water per inch of soil. The capacity, in

inches, in a 60-inch profile or to a limiting layer is

expressed as

Inches

Very low..............................................................0 to 3

Low ...................................................................3 to 6

Moderate...........................................................6 to 9

High ...............................................................9 to 12

Very high.................................................More than 12

Basal till. Compact glacial till deposited beneath the ice.

Base saturation. The degree to which material having

cation exchange properties is saturated with

exchangeable bases (sum of Ca, Mg, Na, K),

expressed as a percentage of the total cation

exchange capacity.

Bedding planes. Fine stratifications, less than 5

millimeters thick, in unconsolidated alluvial, eolian,

lacustrine, or marine sediments.

Bedrock. The solid rock that underlies the soil and other

unconsolidated material or that is exposed at the

surface.

Bottom land. The normal flood plain of a stream,

subject to flooding.

Boulders. Rock fragments larger than 2 feet (60

centimeters) in diameter.

Cable yarding. A method of moving felled trees to a nearby

central area for transport to a processing facility. Most

cable yarding systems involve use of a drum, a pole,

and wire cables in an arrangement similar to that of a rod

and reel used for fishing. To reduce friction and soil

disturbance, felled trees generally are reeled in while

one end is lifted or the entire log is suspended.

Capillary water. Water held as a film around soil

particles and in tiny spaces between particles.

Surface tension is the adhesive force that holds

capillary water in the soil.

Cation. An ion carrying a positive charge of electricity.

The common soil cations are calcium, potassium,

magnesium, sodium, and hydrogen.

Cation-exchange capacity. The total amount of exchangeable

cations that can be held by the soil, expressed in terms

of milliequivalents per 100 grams of soil at neutrality (pH

7.0) or at some other stated pH value. The term, as

applied to soils, is synonymous with base-exchange

capacity, but is more precise in meaning.

Channery soil. A soil that is, by volume, more than 15

percent thin, flat fragments of sandstone, shale, slate,

limestone, or schist as much as 6 inches along the

longest axis. A single piece is called a fragment.

Clay. As a soil separate, the mineral soil particles less than 0.002

millimeter in diameter. As a soil textural class, soil material that

is 40 percent or more clay, less than 45 percent sand, and

less than 40 percent silt.

Clay film. A thin coating of oriented clay on the surface of a

soil aggregate or lining pores or root channels. Synonyms:

clay coating, clay skin.

Claypan. A slowly permeable soil horizon that contains

much more clay than the horizons above it. A claypan

is commonly hard when dry and plastic or stiff when

wet.

Climax vegetation. The stabilized plant community on a

particular site. The plant cover reproduces itself and

does not change so long as the environment remains

the same.

CMAI (culmination of the mean annual increment). The

average annual increase per acre in the volume
of a stand. Computed by dividing the total volume of

the stand by its age. As the stand increases in age, the

mean annual increment continues to increase until

mortality begins to reduce the rate of increase. The

point where the stand reaches its maximum annual

rate of growth is called the culmination of the mean

annual increment.

Coarse fragments. If round, mineral or rock particles 2

millimeters to 25 centimeters (10 inches) in

diameter; if flat, mineral or rock particles

(flagstone) 15.2 to 38.1 centimeters (6 to 15 inches)

long.

Coarse textured soil. Sand or loamy sand.

Cobblestone (or cobble). A rounded or partly rounded

fragment of rock 3 to 10 inches (7.5 to 25 centimeters)

in diameter.

Colluvium. Soil material, rock fragments, or both moved by

creep, slide, or local wash and deposited at the base

of steep slopes.

Complex, soil. A map unit of two or more kinds of soil in

such an intricate pattern or so small in area that it is not

practical to map them separately at the selected scale

of mapping. The pattern and proportion of the soils are

somewhat similar in all areas.

Compressible (in tables). Excessive decrease in volume of

soft soil under load.

Consistence, soil. The feel of the soil and the ease with

which a lump can be crushed by the fingers. Terms

commonly used to describe consistence areLoose. -Noncoherent when dry or moist; does not hold

together in a mass.

Friable.-When moist, crushes easily under gentle pressure

between thumb and forefinger and can be pressed

together into a lump.

Firm.-When moist, crushes under moderate

pressure between thumb and forefinger, but

resistance is distinctly noticeable.

Plastic.-When wet, readily deformed by moderate

pressure but can be pressed into a lump; will form a

"wire" when rolled between thumb and forefinger.

Sticky.-When wet, adheres to other material and tends

to stretch somewhat and pull apart rather than to pull

free from other material.

Hard-When dry, moderately resistant to pressure; can be

broken with difficulty between thumb and forefinger.

Soft.-When dry, breaks into powder or individual

grains under very slight pressure.

Cemented-Hard; little affected by moistening.

Control section. The part of the soil on which classification

is based. The thickness varies among different kinds of

soil, but for many it is that part of the soil profile

between depths of 10 inches and 40 or 80 inches.

Corrosive. High risk of corrosion to uncoated steel or

deterioration of concrete.

Cover crop. A close-growing crop grown primarily to

improve and protect the soil between periods of

regular crop production, or a crop grown between

trees and vines in orchards and vineyards.

Culmination of the mean annual increment. See

CMAI.

Cutbanks cave (in tables). The walls of excavations

tend to cave in or slough.

Depth to rock (in tables). Bedrock is too near the

surface for the specified use.

Drainage class (natural). Refers to the frequency and

duration of periods of saturation or partial saturation

during soil formation, as opposed to altered drainage,

which is commonly the result of artificial drainage or

irrigation but may be caused by the sudden deepening

of channels or the blocking of drainage outlets. Seven

classes of natural soil drainage are recognized:

Excessively drained.-Water is removed from the soil very

rapidly. Excessively drained soils are commonly very coarse

textured, rocky, or shallow. Some are steep. All are free

of the mottling related to wetness.

Somewhat excessively drained-Water is removed from

the soil rapidly. Many somewhat excessively drained

soils are sandy and rapidly pervious. Some are shallow.

Some are so steep that much of the water they receive

is lost as runoff. All are free of the mottling related to

wetness.

Well drained-Water is removed from the soil readily,

but not rapidly. It is available to plants throughout most

of the growing season, and wetness does not inhibit

growth of roots for significant periods during most

growing seasons. Well drained soils are commonly

medium textured. They are mainly free of mottling.

Moderately well drained.-Water is removed from the

soil somewhat slowly during some periods. Moderately

well drained soils are wet for only a short time during

the growing season, but periodically they are wet long

enough that most mesophytic crops are affected. They

commonly have a slowly pervious layer within or

directly below the solum, or periodically receive high

rainfall, or both.

Somewhat poorly drained.-Water is removed slowly

enough that the soil is wet for significant periods during

the growing season. Wetness markedly restricts the

growth of mesophytic crops unless artificial drainage is

provided. Somewhat poorly drained soils commonly

have a slowly pervious

layer, a high water table, additional water from seepage,

nearly continuous rainfall, or a combination of these.

 Poorly drained.-Water is removed so slowly that the

soil is saturated periodically during the growing season

or remains wet for long periods. Free water is

commonly at or near the surface for long enough

during the growing season that most mesophytic crops

cannot be grown unless the soil is artificially drained.

The soil is not continuously saturated in layers directly

below plow depth. Poor drainage
results from a high water table, a slowly pervious

layer within the profile, seepage, nearly continuous

rainfall, or a combination of these.

Very poorly drained.-Water is removed from the

soil so slowly that free water remains at or on the

surface during most of the growing season. Unless

the soil is artificially drained, most mesophytic crops

cannot be grown. Very poorly drained soils are

commonly level or depressed and are frequently

ponded. Yet, where rainfall is high and nearly continuous,

they can have moderate or high slope gradients.

Drainage, surface. Runoff, or surface flow of water, from

an area.

Duff. A term used to identify a generally firm organic

layer on the surface of mineral soils. It consists of

fallen plant material that is in the process of

decomposition and includes everything from the litter

on the surface to underlying pure humus.

Esker (geology). A narrow, winding ridge of stratified gravelly

and sandy drift deposited by a stream flowing in a

tunnel beneath a glacier.

Excess alkali (in tables). Excess exchangeable sodium in

the soil. The resulting poor physical properties restrict

the growth of plants.

Excess fines (in tables). Excess silt and clay in the soil. The

soil does not provide a source of gravel or sand for

construction purposes.

Excess lime (in tables). Excess carbonates in the soil

that restrict the growth of some plants.

Excess salts (in tables). Excess water-soluble salts in

the soil that restrict the growth of most. plants.

Fast intake (in tables). The rapid movement of water

into the soil.

Fertility, soil. The quality that enables a soil to provide plant

nutrients, in adequate amounts and in proper balance, for

the growth of specified plants when light, moisture,

temperature, tilth, and other growth factors are

favorable.

Fibric soil material (peat). The least decomposed of all organic

soil material. Peat contains a large amount of well

preserved fiber that is readily identifiable according

to botanical origin. Peat has the lowest bulk density and

the highest water content at saturation of all organic

soil material.

Field moisture capacity. The moisture content of a soil,

expressed as a percentage of the ovendry weight, after

the gravitational, or free, water has drained away; the

field moisture content 2 or 3 days after a

soaking rain; also called normal field capacity,

normal moisture capacity, or capillary capacity.

Fill slope. A sloping surface consisting of excavated soil

material from a road cut. It is commonly on the downhill

side of the road.

Fine textured soil. Sandy clay, silty clay, and clay.

Firebreak. Areas cleared of flammable material to stop

or help to control creeping or running fires. It also

serves as a line from which to work and to facilitate

the movement of men and equipment in fire fighting.

Designated roads also serve as firebreaks.

Flagstone. A thin fragment of sandstone, limestone, slate,

shale, or (rarely) schist, 6 to 15 inches (15 to 37.5

centimeters) long.

Flood plain. A nearly level alluvial plain that borders a

stream and is subject to flooding unless protected

artificially.

Foot slope. The inclined surface at the base of a hill.

Forb. Any herbaceous plant not a grass or a sedge.

Fragipan. A loamy, brittle subsurface horizon low in

porosity and content of organic matter and low or

moderate in clay but high in silt or very fine sand. A

fragipan appears cemented and restricts roots. When

dry, it is hard or very hard and has a higher bulk density

than the horizon or horizons above. When moist, it

tends to rupture suddenly under pressure rather than to

deform slowly.

Frost action (in tables). Freezing and thawing of soil

moisture. Frost action can damage roads, buildings

and other structures, and plant roots.

Genesis, soil. The mode of origin of the soil. Refers

especially to the processes or soil-forming factors

responsible for the formation of the solum, or true

soil, from the unconsolidated parent material.

Glacial drift (geology). Pulverized and other rock material

transported by glacial ice and then deposited. Also

the sorted and unsorted material deposited by

streams flowing from glaciers.

Glacial outwash (geology). Gravel, sand, and silt, commonly

stratified, deposited by glacial melt water.

Glacial till (geology). Unsorted, nonstratified glacial drift

consisting of clay, silt, sand, and boulders transported

and deposited by glacial ice.

Glaciofluvial deposits (geology). Material moved by glaciers

and subsequently sorted and deposited by streams

flowing from the melting ice. The deposits are stratified

and occur as kames, eskers, deltas, and outwash

plains.

Glaciolacustrine deposits. Material ranging from fine clay to

sand derived from glaciers and deposited in glacial

lakes mainly by glacial melt water. Many deposits are

interbedded or laminated.

Gleyed soil. Soil that formed under poor drainage, resulting

in the reduction of iron and other elements in the

profile and in gray colors and mottles.

Gravel. Rounded or angular fragments of rock up to 3

inches (2 millimeters to 7.5 centimeters) in diameter. An

individual piece is a pebble.

Green manure crop (agronomy). A soil-improving crop

grown to be plowed under in an early stage of maturity

or soon after maturity.

Ground water (geology). Water filling all the unblocked

pores of underlying material below the water table.

Hardpan. A hardened or cemented soil horizon, or layer.

The soil material is sandy, loamy, or clayey and is

cemented by iron oxide, silica, calcium carbonate, or

other substance.
Hemic soil material (mucky peat). Organic soil material

intermediate in degree of decomposition between the

less decomposed fibric and the more decomposed sapric

material.

Horizon, soil. A layer of soil, approximately parallel to the

surface, having distinct characteristics produced by soilforming processes. In the identification of soil horizons,

an upper case letter represents the major horizons.

Numbers or lower case letters that follow represent

subdivisions of the major horizons. An explanation of

the subdivisions is given in the Soil Survey Manual. The

major horizons of mineral soil are as follows:

O horizon.-An organic layer of fresh and decaying

plant residue at the surface of a mineral soil. A horizon.-

The mineral horizon at or near the surface in which an.

accumulation of humified organic matter is mixed with the

mineral material. Also, a plowed surface horizon, most

of which was originally part of a B horizon.

B horizon.-The mineral horizon below an A horizon. The B

horizon is in part a layer of transition from the overlying

A to the underlying C horizon. The B horizon also has

distinctive characteristics such as (1) accumulation of clay,

sesquioxides, humus, or a combination of these; (2)

prismatic or blocky structure; (3) redder or browner

colors than those in the A horizon; or (4) a combination

of these. The combined A and B horizons are

generally called the solum, or true soil. If a soil does

not have a B horizon, the A horizon alone is the

solum.

C horizon.-The mineral horizon or layer, excluding

indurated bedrock, that is little affected by soil-forming

processes and does not have the properties typical of

the A or B horizon. The material of a C horizon may be

either like or unlike that in which the solum formed. If

the material is known to differ from that in the solum,

the Roman numeral II precedes the letter C.

R layer-Consolidated rock beneath the soil. The

rock commonly underlies a C horizon, but can be

directly below an A or a B horizon.

Humus. The well decomposed, more or less stable part of

the organic matter in mineral soils.

Hydrologic soil groups. Refers to soils grouped according to

their runoff-producing characteristics. The chief

consideration is the inherent capacity of soil bare of

vegetation to permit infiltration. The slope and the kind

of plant cover are not considered but are separate

factors in predicting runoff. Soils are assigned to four

groups. In group A are soils having a high infiltration rate

when thoroughly wet and having a low runoff potential. They

are mainly deep, well drained, and sandy or gravelly. In group

D, at the other extreme, are soils having a very slow

infiltration rate and thus a high runoff potential. They

have a claypan or clay layer at or near the surface,

have a permanent high water table, or are shallow

over nearly impervious bedrock or other material. A

soil is assigned to two hydrologic groups if part of the

acreage is artificially drained and part is undrained.

Illuviation. The movement of soil material from one

horizon to another in the soil profile. Generally,

material is removed from an upper horizon and

deposited in a lower horizon.

Infiltration. The downward entry of water into the

immediate surface of soil or other material, as

contrasted with percolation, which is movement of

water through soil layers or material.

Infiltration rate. The rate at which water penetrates the

surface of the soil at any given instant, usually

expressed in inches per hour. The rate can be limited

by the infiltration capacity of the soil or the rate at

which water is applied at the surface.

Intake rate. The average rate of water entering the soil

under irrigation. Most soils have a fast initial rate; the

rate decreases with application time. Therefore, intake

rate for design purposes is not a constant but is a

variable depending on the net irrigation application. The

rate of water intake in inches per hour is expressed as

follows:

Less than 0.2 .............................................. very low

0.2 to 0.4 ............................................................. low

0.4 to 0.75 ............................................ moderately low

0.75 to 1.25 ................................................... moderate

1.25 to 1.75........................................ moderately high

1.75 to 2.5............................................................ high

More than 2.5 .............................................very high

Irrigation. Application of water to soils to assist in

production of crops. Methods of irrigation areBorder.-Water is applied at the upper end of a strip in

which the lateral flow of water is controlled by small

earth ridges called border dikes, or borders.

Basin.-Water is applied rapidly to nearly level plains

surrounded by levees or dikes.

Controlled flooding. -Water is released at intervals from

closely spaced field ditches and distributed uniformly

over the field.

Corrugation.-Water is applied to small, closely spaced

furrows or ditches in fields of close-growing crops or in

orchards so that it flows in only one direction.

Drip (or trickle).-Water is applied slowly and under low

pressure to the surface of the soil or into the soil

through such applicators as emitters, porous tubing, or

perforated pipe.

Furrow-Water is applied in small ditches made by

cultivation implements. Furrows are used for tree and

row crops.

Sprinkler-Water is sprayed over the soil surface through

pipes or nozzles from a pressure system.

Subirrigation.-Water is applied in open ditches or tile

lines until the water table is raised enough to wet the

soil.

Wild flooding.-Water, released at high points, is

allowed to flow onto an area without controlled

distribution.
Kame (geology). An irregular, short ridge or hill of

stratified glacial drift.

Lacustrine deposit (geology). Material deposited in lake

water and exposed when the water level is lowered

or the elevation of the land is raised.

Large stones (in tables). Rock fragments 3 inches (7.5

centimeters) or more across. Large stones adversely affect

the specified use of the soil.

Leaching. The removal of soluble material from soil or

other material by percolating water.

Liquid limit. The moisture content at which the soil

passes from a plastic to a liquid state.

Loam. Soil material that is 7 to 27 percent clay particles, 28

to 50 percent silt particles, and less than 52 percent

sand particles.

Loess. Fine grained material, dominantly of silt-sized

particles, deposited by wind.

Low strength. The soil is not strong enough to support

loads.

Medium textured soil. Very fine sandy loam, loam, silt loam,

or silt.

Metamorphic rock. Rock of any origin altered in mineralogical

composition, chemical composition, or structure by heat,

pressure, and movement. Nearly all such rocks are

crystalline.

Mineral soil. Soil that is mainly mineral material and low in

organic material. Its bulk density is more than that of

organic soil.

Moderately coarse textured soil. Sandy loam and fine

sandy loam.

Moderately fine textured soil. Clay loam, sandy clay loam,

and silty clay loam.

Moraine (geology). An accumulation of earth, stones, and other

debris deposited by a glacier. Some types are terminal,

lateral, medial, and ground.

Morphology, soil. The physical makeup of the soil, including

the texture, structure, porosity, consistence, color, and

other physical, mineral, and biological properties of the

various horizons, and the thickness and arrangement of

those horizons in the soil profile.

Mottling, soil. Irregular spots of different colors that vary in

number and size. Mottling generally indicates poor

aeration and impeded drainage. Descriptive terms are

as follows: abundance-few, common, and many, sizefine, medium, and coarse; and contrast-faint, distinct,

and prominent. The size measurements are of the

diameter along the greatest dimension. Fine indicates

less than 5 millimeters (about 0.2 inch); medium, from 5

to 15 millimeters (about 0.2 to 0.6 inch); and coarse,

more than 15 millimeters (about 0.6 inch).

Muck. Dark colored, finely divided, well decomposed

organic soil material. (See Sapric soil material.)

Munsell notation. A designation of color by degrees of the

three simple variables-hue, value, and chroma. For

example, a notation of 10YR 6/4 is a color of 10YR hue,

value of 6, and chroma of 4.

Neutral soil. A soil having a pH value between 6.6 and 7.3.

(See Reaction, soil.)

Organic matter. Plant and animal residue in the soil in

various stages of decomposition.

Outwash, glacial. Stratified sand and gravel produced by

glaciers and carried, sorted, and deposited by glacial

melt water.

Outwash plain. A landform of mainly sandy or coarse

textured material of glaciofluvial origin. An outwash

plain is commonly smooth; where pitted, it is generally

low in relief.

Pan. A compact, dense layer in a soil that impedes the

movement of water and the growth of roots. For

example, hardpan, fragipan, claypan, plowpan, and

traffic pan.

Parent material. The unconsolidated organic and

mineral material in which soil forms.

Peat. Unconsolidated material, largely undecomposed organic

matter, that has accumulated under excess moisture.

(See Fibric soil material.)

Pedon. The smallest volume that can be called "a soil." A

pedon is three dimensional and large enough to permit

study of all horizons. Its area ranges from about 10 to

100 square feet (1 square meter to 10 square meters),

depending on the variability of the soil.

Percs slowly (in tables). The slow movement of water

through the soil adversely affecting the specified use.

Permeability. The quality of the soil that enables water to

move downward through the profile. Permeability is

measured as the number of inches per hour that water

moves downward through the saturated soil. Terms

describing permeability are:

Very slow......................................less than 0.06 inch

Slow ............................................... 0.06 to 0.20 inch

Moderately slow.................................. 0.2 to 0.6 inch

Moderate ................................. 0.6 inch to 2.0 inches

Moderately rapid..............................2.0 to 6.0 inches

Rapid................................................6.0 to 20 inches

Very rapid...................................more than 20 inches

pH value. A numerical designation of acidity and

alkalinity in soil. (See Reaction, soil.)

Piping (in tables). Formation of subsurface tunnels or

pipelike cavities by water moving through the soil.

Pitting (in tables). Pits caused by melting ground ice. They

form on the soil after plant cover is removed.

Plasticity index. The numerical difference between the

liquid limit and the plastic limit; the range of moisture

content within which the soil remains plastic.

Plastic limit. The moisture content at which a soil

changes from semisolid to plastic.

Ponding. Standing water on soils in closed depressions.

The water can be removed only by percolation or

evapotranspiration.

Poorly graded. Refers to a coarse grained soil or soil

material consisting mainly of particles of nearly the

same size. Because there is little difference in size
of the particles, density can be increased only

slightly by compaction.

Poor outlets (in tables). Refers to areas where surface or

subsurface drainage outlets are difficult or

expensive to install.

Post and piling outlets. A market location where posts and

pilings are bought, processed, and sold.

Profile, soil. A vertical section of the soil extending through

all its horizons and into the parent material.

Reaction, soil. A measure of acidity or alkalinity of a soil,

expressed in pH values. A soil that tests to pH 7.0 is

described as precisely neutral in reaction because it is

neither acid nor alkaline. The degree of acidity or

alkalinity is expressed aspH

Extremely acid ................................................... Below 4.5

Very strongly acid ..............................................4.5 to 5.0

Strongly acid......................................................5.1 to 5.5

Medium acid........................................................5.6 to 6.0

Slightly acid .........................................................6.1 to 6.5

Neutral ..............................................................6.6 to 7.3

Mildly alkaline ......................................................7.4 to 7.8

Moderately alkaline ..............................................7.9 to 8.4

Strongly alkaline...................................................8.5 to 9.0

Very strongly alkaline .................................... 9.1 and higher

Regolith. The unconsolidated mantle of weathered rock

and soil material on the earth's surface; the loose earth

material above the solid rock.

Relief. The elevations or inequalities of a land surface,

considered collectively.

Residuum (residual soil material). Unconsolidated,

weathered, or partly weathered mineral material that

accumulated as consolidated rock disintegrated in place.

Rippable. Bedrock or hardpan can be excavated using a

single-tooth ripping attachment mounted on a tractor

with a 200-300 draw bar horsepower rating.

Road cut. A sloping surface produced by mechanical

means during road construction. It is commonly on the

uphill side of the road.

Rock fragments. Rock or mineral fragments having a

diameter of 2 millimeters or more; for example,

pebbles, cobbles, stones, and boulders.

Rooting depth (in tables). Shallow root zone. The soil is

shallow over a layer that greatly restricts roots.

Root zone. The part of the soil that can be penetrated by

plant roots.

Runoff. The precipitation discharged into stream channels

from an area. The water that flows off the surface of

the land without sinking into the soil is called surface

runoff. Water that enters the soil before reaching

surface streams is called ground-water runoff or

seepage flow from ground water.

Sand. As a soil separate, individual rock or mineral

fragments from 0.05 millimeter to 2.0 millimeters in

diameter. Most sand grains consist of quartz. As a soil

textural class, a soil that is 85 percent or more sand

and not more than 10 percent clay.

Sandstone. Sedimentary rock containing dominantly sandsize particles.

Sapric soil material (muck). The most highly decomposed of

all organic soil material. Muck has the least amount of

plant fiber, the highest bulk density, and the lowest

water content at saturation of all organic soil material.

Salty water (in tables.) Water that is too salty for

consumption by livestock.

Sedimentary rock. Rock made up of particles deposited

from suspension in water. The chief kinds of sedimentary

rock are conglomerate, formed from gravel; sandstone,

formed from sand; shale, formed from clay; and

limestone, formed from soft masses of calcium

carbonate. There are many intermediate types. Some

wind-deposited sand is consolidated into sandstone.

Seepage (in tables). The movement of water through the

soil. Seepage adversely affects the specified use.

Series, soil. A group of soils that have profiles that are

almost alike, except for differences in texture of the

surface layer or of the underlying material. All the soils

of a series have horizons that are similar in

composition, thickness, and arrangement.

Shale. Sedimentary rock formed by the hardening of a

clay deposit.

Shrink-swell. The shrinking of soil when dry and the

swelling when wet. Shrinking and swelling can

damage roads, dams, building foundations, and other

structures. It can also damage plant roots.

Silt. As a soil separate, individual mineral particles that

range in diameter from the upper limit of clay (0.002

millimeter) to the lower limit of very fine sand (0.05

millimeter). As a soil textural class, soil that is 80

percent or more silt and less than 12 percent clay.

Siltstone. Sedimentary rock made up of dominantly siltsized particles.

Sinkhole. A depression in the landscape where

limestone has been dissolved.

Site class. A grouping of site indexes into 5 to 7

production capability levels. Each level can be

represented by a site curve.

Site curve (50-year). A set of related curves on a graph that

shows the average height of dominant trees for a range

of ages on soils that differ in productivity. Each level is

represented by a curve. The bases of the curves are the

height of dominant trees that are 50 years old or are 50

years old at breast height.

Site curve (100-year). A set of related curves on a graph

that shows the average height of dominant and

codominant trees for a range of ages on soils that

differ in productivity. Each level is represented by a

curve. The bases of the curves are the height of

dominant and codominant trees that are 100 years old

or are 100 years old at breast height.

Site index. The height that dominant or dominant and

codominant trees reach at 50 years total age or breastheight age, or 100 years total age or breast-height age.

With this index and the age of the stand of trees, yield

can be determined by using the appropriate yield table.
Slippage (in tables). Soil mass susceptible to movement

downslope when loaded, excavated, or wet.

Slope. The inclination of the land surface from the

horizontal. Percentage of slope is the vertical

distance divided by horizontal distance, then

multiplied by 100. Thus, a slope of 20 percent is a

drop of 20 feet in 100 feet of horizontal distance.

Slow intake (in tables). The slow movement of water

into the soil.

Slow refill (in tables). The slow filling of ponds, resulting

from restricted permeability in the soil.

Small stones (in tables). Rock fragments less than 3 inches

(7.5 centimeters) in diameter. Small stones adversely

affect the specified use of the soil.

Soil. A natural, three-dimensional body at the earth's

surface. It is capable of supporting plants and has

properties resulting from the integrated effect of

climate and living matter acting on earthy parent

material, as conditioned by relief over periods of

time.

Soil separates. Mineral particles less than 2 mm in

equivalent diameter and ranging between specified size

limits. The names and sizes of separates recognized in the

United States are as follows:

 Millimeters

Very coarse sand .......................................2.0 to 1.0

Coarse sand...............................................1.0 to 0.5

Medium sand................................................ 0.5 to 0.25

Fine sand .................................................. 0.25 to 0.10

Very fine sand ............................................. 0.10 to 0.05

Silt............................................................0.05 to 0.002

Clay .................................................. less than 0.002

Solum. The upper part of a soil profile, above the C horizon,

in which the processes of soil formation are active. The

solum in soil consists of the A and B horizons.

Generally, the characteristics of the material in these

horizons are unlike those of the underlying material.

The living roots and plant and animal activities are

largely confined to the solum.

Stones. Rock fragments 10 to 24 inches (25 to 60,

centimeters) in diameter.

Stony. Refers to a soil containing stones in numbers

that interfere with or prevent tillage.

Structure, soil. The arrangement of primary soil

particles into compound particles or aggregates. The

principal forms of soil structure are platy (laminated),

prismatic (vertical axis of aggregates longer than

horizontal), columnar (prisms with rounded tops),

blocky (angular or subangular), and

granular. Structureless soils are either single grained

(each grain by itself, as in dune sand) or massive (the

particles adhering without any regular cleavage, as in many

hardpans).

Subsoil. Technically, the B horizon; roughly, the part of

the solum below plow depth.

Substratum. The part of the soil below the solum.

Subsurface layer. Technically, the A2 horizon. Generally refers

to a leached horizon lighter in color and lower

in content of organic matter than the overlying

surface layer.

Surface layer. The soil ordinarily moved in tillage, or its

equivalent in uncultivated soil, ranging in depth from 4 to

10 inches (10 to 25 centimeters). Frequently designated

as the "plow layer," or the "Ap horizon."

Taxadjuncts. Soils that cannot be classified in a series

recognized in the classification system. Such soils are

named for a series they strongly resemble and are

designated as taxadjuncts to that series because

they differ in ways too small to be of consequence in

interpreting their use and behavior.

Terminal moraine. A belt of thick glacial drift that generally

marks the termination of important glacial advances.

Terrace. An embankment, or ridge, constructed across

sloping soils on the contour or at a slight angle to the

contour. The terrace intercepts surface runoff so that

water soaks into the soil or flows slowly to a prepared

outlet. A terrace in a field is generally built so that the

field can be farmed. A terrace intended mainly for

drainage has a deep channel that is maintained in

permanent sod.

Terrace (geologic). An old alluvial plain, ordinarily flat or

undulating, bordering a river, a lake, or the sea.

Texture, soil. The relative proportions of sand, silt, and

clay particles in a mass of soil. The basic textural

classes, in order of increasing proportion of fine

particles, are sand, loamy sand, sandy loam, loam, silt

loam, silt, sandy clay loam, clay loam, silty clay loam,

sandy clay, silty clay, and clay. The sand,

loamy sand, and sandy loam classes may be further

divided by specifying "coarse," "fine," or "very fine.

Thin layer (in tables). Otherwise suitable soil material too

thin for the specified use.

Till plain. An extensive flat to undulating area underlain by

glacial till.

Tilth, soil. The physical condition of the soil as related to

tillage, seedbed preparation, seedling emergence, and

root penetration.

Toe slope. The outermost inclined surface at the base of

a hill; part of a foot slope.

Topsoil. The upper part of the soil, which is the most

favorable material for plant growth. It is ordinarily rich

in organic matter and is used to topdress roadbanks,

lawns, and land affected by mining.

Tuff. A compacted deposit that is 50 percent or more

volcanic ash and dust.

Unstable fill (in tables). Risk of caving or sloughing on

banks of fill material.

Upland (geology). Land at a higher elevation, in general,

than the alluvial plain or stream terrace; land above the

lowlands along streams.

Valley fill. In glaciated regions, material deposited in stream

valleys by glacial melt water. In nonglaciated regions,

alluvium deposited by heavily loaded streams.
Variant, soil. A soil having properties sufficiently different

from those of other known soils to justify a new series

name, but occurring in such a limited geographic area

that creation of a new series is not justified.

Water bars. Smooth, shallow ditches or depressional

areas that are excavated at an angle across a sloping

road. They are used to reduce the downward velocity

of water and divert it off and away from the road

surface. Water bars can easily be driven over if

constructed properly.

Weathering. All physical and chemical changes produced

in rocks or other deposits at or near the earth's

surface by atmospheric agents. These

changes result in disintegration and decomposition of

the material.

Well graded. Refers to soil material consisting of coarse

grained particles that are well distributed over a wide

range in size or diameter. Such soil normally can be

easily increased in density and bearing properties by

compaction. Contrasts with poorly graded soil.

Wilting point (or permanent wilting point). The moisture

content of soil, on an ovendry basis, at which a plant

(specifically sunflower) wilts so much that it does not

recover when placed in a humid, dark chamber.

Windthrow. The action of uprooting and tipping over

trees by the wind.