Foreword

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

in the survey 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, 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 ensure

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 Whatcom County Area, Washington issued May 1992.

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
Soil Survey of

Whatcom County Area, Washington

By Alan Goldin, Ph.D., Soil Conservation Service

Fieldwork by Alan Goldin, Barry Strickler, Sanderson Page, and Dennis Robinson, Soil

Conservation Service; and David Hammer, Ralph Minden, Robert M. Freimark, George

Carnine, Roger Stark, Andrew Card, and Reed Young, Washington State Department of

Natural Resources

United States Department of Agriculture, Soil Conservation Service, in

cooperation with

Washington State Department of Natural Resources and Washington State University,

Agriculture Research Center

The survey area is in the northwest corner of

Washington (fig. 1). It has an area of about 809 square

miles, or 518,135 acres. The population of the county in

1980 was 106,701. Bellingham, the county seat, had a

population of 45,794. It is in the southwestern part of the

survey area.

The survey area is bounded on the west by the Strait of

Georgia, on the south by Skagit County, on the east by the

Mount Baker-Snoqualmie National Forest, and on the north

by Canada. A few privately owned areas are interspersed

in the national forest near Baker Lake. The survey area

ranges from 18 to 34 miles from east to west and is about

25 miles from north to south. Point Roberts is located on a

peninsula 10 miles west of the main part of the survey

area. It is connected to the rest of the survey area by roads

that run through Canada.

The northwestern half of the survey area is nearly level

to rolling. It includes flood plains, outwash terraces, and

glaciomarine drift plains at elevations of sea level to 300

feet above sea level. The southeastern part is dominantly

steep and mountainous, except for the flood plains along

the three forks of the Nooksack River. Dairy farming, hay

and pasture, and forestry are the main economic

enterprises in the survey area.

Soil scientists have identified about 100 different kinds of

soil in the survey area. The soils have a wide range of

texture, natural drainage, and other characteristics. The

soils along the major drainageways

Figure 1.-Location of Whatcom County In Washington.

are suited to cropland, hay, and pasture. Wetness and the

hazard of flooding are the main management concerns.

The soils on outwash terraces are suited to cropland, hay

and pasture, and woodland. A moderate available water

capacity and a high water table are the main limitations.

Extensive tile drainage has made the soils on the outwash

terraces and flood plains well
suited to field crops. Soils on glaciomarine drift plains and

lacustrine terraces are used for hay and pasture, cropland,

or woodland. Wetness and slow permeability are the main

limitations. Soils on foothills and mountains are suited to

woodland. The main limitations are the slope and wetness.

An older survey, "Soil Survey of Whatcom County,

Washington," was published in 1953 (34). This earlier

survey covers a part of the present survey. The present

survey, however, updates the earlier survey and provides

additional information and larger maps that show the soils

in greater detail.

Descriptions, names, and delineations of soils in this soil

survey do not fully agree with those on soil maps for

adjacent survey areas. Differences are the result of better

knowledge of soils, modifications in series concepts,

intensity of mapping, or the extent of soils within the survey

area.

General Nature of the Survey Area

This section gives general information about the

Whatcom County area. It describes history and

development; climate; and physiology, relief, and

drainage.

History and Development

Whatcom County was established by the legislature of

the territory on March 9, 1854. The county was named for a

Nooksack Indian chief. Whatcom was also the name of the

first town on Bellingham Bay and was the predecessor of

the city of Bellingham.

Agriculture and forestry have been the major industries

in Whatcom County since settlement began. The county

supports more dairy cattle than any other county in the

Pacific Northwest. Hay, pasture, truck vegetables, berries,

and seed potatoes are important crops. Fishing,

recreation, and mining also are major contributors to the

economy. The county's proximity to Canada increases its

market for goods and services.

Climate

Prepared by the National Climatic Data Center, Asheville, North

Carolina.

The climate of the survey 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. At the lower elevations freezing temperatures

generally occur under the influence of dry air masses. During

summer, rainfall is extremely light, so crops growing actively

during this period need

irrigation. Often several weeks pass without

precipitation. During the rest of the year, rains are

frequent, especially in late fall and winter.

In most winters one or two storms contain strong and

sometimes damaging winds, and in some years the

accompanying heavy rains cause serious flooding. Ice-laden,

northeast winds moving down the valley of the Fraser River

are particularly damaging. In some years, either during

winter or summer, a large invasion of a continental air mass

from the east causes abnormal temperatures. As a result,

several consecutive days are well below freezing in winter

or a week or longer is sweltering in summer.

Table 1 gives data on temperature and precipitation for

the survey area as recorded at Blaine, Glacier, Bellingham,

and Clearbrook, Washington. 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 Blaine, Glacier,

Bellingham, and Clearbrook are 39, 34, 39, and 38 degrees

F, respectively. The average daily minimum temperature is

33 degrees at Blaine and Bellingham, 28 degrees at Glacier,

and 32 degrees at Clearbrook. The lowest temperature on

record, which occurred at Glacier, is -12 degrees. In

summer, the average temperature is 60 degrees at Blaine

and 61 degrees at Glacier, Bellingham, and Clearbrook. The

average daily maximum temperature is about 73 degrees at

all four locations. The highest recorded temperature, which

occurred at Clearbrook, is 102 degrees.

Growing degree days are shown in table 1. They 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 (41

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 about 41 inches at Blaine,

67 inches at Glacier, 36 inches at Bellingham, and 46

inches at Clearbrook. Of this, 30 percent usually falls in

April through September. The growing season for most

crops falls within this period. The heaviest 1-day rainfall

during the period of record was 4.65 inches at Glacier on

December 14, 1959. Thunderstorms occur on about 6 days

each year.

The average seasonal snowfall is 12 to 14 inches at

Blaine and Bellingham, 48 inches at Glacier, and 19 inches

at Clearbrook. During the period of record, the greatest

snow depth in the survey area at any one time was 37

inches. On the average, 2 or fewer days at Blaine,

Bellingham, and Clearbrook and 7 days at Glacier have at

least 1 inch of snow on the ground. The
number of such days varies 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 sun shines 60 percent of the

time possible in summer and 25 percent in winter. The

prevailing wind is from the southwest. Average wind speed

is highest, 10 miles per hour, in winter.

Physiography, Relief, and Drainage

The survey area can be divided into two distinct

physiographic regions. These regions are the Cascade

Range and the Whatcom Basin (14).

The Cascade Range rises abruptly from the floor of the

Whatcom Basin, culminating in the snowfields and glaciers

of Mount Baker, Mount Shuksan, and the Twin Sisters

Mountain. The topography is extremely rugged. It consists

of pre-Tertiary metamorphic and Tertiary sedimentary

rocks with a mantle that is dominantly Vashon till and

some outwash (11). The mountains in the survey area rise

to about 5,500 feet. The higher elevations have young,

narrow, steep-sided valleys, which become broader and

mantled with alluvium and glacial drift as they descend to

the Whatcom Basin.

The Whatcom Basin ranges in elevation from sea level

to about 600 feet above sea level. It lies entirely within the

Puget Trough of the Pacific Border physiographic

province. The low topography of the Basin is a result of

several glaciations, marine submergences and rebounds,

postglacial fluvial action, and eolian deposition. It consists

of hummocky glaciomarine drift plains; nearly level

glaciofluvial terraces that have large bogs; and rolling,

drift-capped uplands overlooking the broad flood plain of

the Nooksack River.

The Whatcom Basin consists of seven significant upland

plateau areas and three lowland terraces (14, 46). The

seven upland provinces are the Birch Point Upland, a small

peninsular area southwest of Blaine; the Boundary Upland,

east of Blaine extending across the international boundary

into Canada; the Mountain View Upland, west of Ferndale;

the King Mountain Upland, extending north from Bellingham

to the Nooksack River Valley; the Lummi Peninsula,

between Lummi Bay and Bellingham Bay; Lummi Island;

and Point Roberts, a small peninsular projection of Canada.

The three lowland areas are the Custer Trough, which

trends northwest to Drayton Harbor and Birch Bay; the

Lynden Terrace, which extends westward from the Sumas

River Valley to the Boundary Upland and southward to the

Nooksack and Custer Trough bottom land; and the flood

plains along the Nooksack and Sumas Rivers.

The Birch Point Upland, which is about 4 square miles

in size, is bounded on three sides by steep cliffs. Its

maximum elevation is about 265 feet.

The Boundary Upland is about 10 miles long and 3

miles wide. It reaches an elevation of nearly 500 feet. The

Boundary and Birch Point Uplands are till and glaciomarine

drift that have a mantle of sand and gravel more than 3 feet

thick.

The Mountain View Upland embraces an area of about

42 square miles. It reaches an elevation of 385 feet. The

western border of the upland consists of steep sea cliffs,

which drop to the Georgia Strait. The upland is bordered on

the north by the Custer Trough and on the east and south

by the flood plains along the Nooksack and Lummi Rivers.

It is dominantly impermeable glaciomarine drift that has a

veneer of sand and gravel.

The King Mountain Upland rises to the south from the

Nooksack River Valley. It reaches a maximum elevation

of about 500 feet and then grades into the slopes of the

Cascade foothills. It is predominantly glaciomarine drift,

although outcrops of Tertiary sandstone protrude

through the unconsolidated materials.

The Lummi Peninsula was formerly an island. The

connection between the island and the mainland was

affected by deposition of fine-grained deltaic deposits,

probably from the Nooksack River. The peninsula is a low,

rolling surface, which is dominantly impermeable

glaciomarine drift that has a veneer of sand and gravel in

places. The maximum elevation is about 170 feet. No

perennial streams are on the peninsula.

Lummi Island is a northwest-southeast trending

island about 9 miles long and 1.5 miles wide. It lies

southwest of Lummi Peninsula. The northwestern part of the

island is a low, rolling glaciomarine and till-capped surface

that has a mantle of sand and gravel more than 3 feet thick.

The southeastern part consists of metamorphic rock. It is

steeply sloping and reaches a maximum elevation of 1,665

feet. The average elevation is about 150 feet. No perennial

streams are on the island.

Point Roberts, which is about 5 square miles in size, is

separated from the rest of the survey area by land that is

part of Canada. Like northern Lummi Island, it is a low,

rolling glaciomarine and till-capped surface and has no

perennial streams. The northeastern part is mantled with

sand and gravel more than 3 feet thick. The maximum

elevation is 235 feet.

The Custer Trough and the Lynden Terrace have a

maximum elevation of 200 feet. They consist of

recessional outwash material of the Fraser glaciations and

glacial materials reworked by the Nooksack River. Within

these two units are silt and clay deposits left by
the impoundment of glacial lakes.

The flood plains along the Nooksack and Sumas Rivers

consist of stratified alluvial material. They are mainly below

an elevation of 50 feet. The flood plain along the South

Fork of the Nooksack River reaches an elevation of about

300 feet. The Sumas River is an underfit stream. It

occupies a valley that was used by the Fraser River during

the Pleistocene. At that time the Fraser River flowed south

as a result of ice blocks to the north.

The drainage of the survey area is dominantly through

the Nooksack River and its tributaries. A few streams,

however, flow directly into Georgia Strait and a small area

drains through the Samish River to Skagit County and

through the Sumas River to Canada (46). The headwaters of

the North, Middle, and South Forks of the Nooksack River

are on Mount Shuksan, Mount Baker, and the Twin Sisters

Mountain, respectively. The forks join near Deming to form

the main channel of the river. Relative relief within the

basins of the three forks is 7,000 to more than 10,000 feet.

Genetically, the three forks are consequent streams. Their

courses are dictated by topography and slope rather than by

geologic structure or faulting.

Seven streams course the glacial drift of the Whatcom

Basin and are maintained primarily by ground-water

discharge from the glacial material. These are Bertrand,

Tenmile, Fishtrap, Dakota, California, Terrell, and Silver

Creeks. Squalicum and Anderson Creeks also are major

tributaries of the Nooksack River.

How This Survey Was Made

This survey was made to provide information about the

soils in the survey area. The information includes a

description of the soils and their location and a discussion

of the suitability, limitations, and management of the soils

for specified uses. Soil scientists observed the steepness,

length, and shape of slopes; the general pattern of

drainage; the kinds of crops and native plants growing on

the soils; and the kinds of bedrock. They dug many holes

to study the soil profile, which is the sequence of natural

layers, or horizons, in a soil. The profile extends from the

surface down into the unconsolidated material in which the

soil formed. The unconsolidated material is devoid of roots

and other living organisms and has not been changed by

other biological activity.

The soils in the survey area occur in an orderly pattern

that is related to the geology, the landforms, relief,

climate, and the natural vegetation of the area. Each kind

of soil is associated with a particular kind of landscape or

with a segment of the landscape. By

observing the soils in the survey area and relating their

position to specific segments of the landscape, a soil

scientist develops a concept, or model, of how the soils

were formed. Thus, during mapping, this model enables the

soil scientist to predict with a considerable degree of

accuracy the kind of soil at a specific location on the

landscape.

Commonly, individual soils on the landscape merge

into one another as their characteristics gradually change.

To construct an accurate soil map, however, soil

scientists must determine the boundaries between the

soils. They can observe only a limited number of soil

profiles. Nevertheless, these observations, supplemented

by an understanding of the soil-landscape relationship,

are sufficient to verify predictions of the kinds of soil in an

area and to determine the boundaries.

Soil scientists recorded the characteristics of the soil

profiles that they studied. They noted soil color, texture,

size and shape of soil aggregates, kind and amount of rock

fragments, distribution of plant roots, reaction, and other

features that enable them to identify soils. After describing

the soils in the survey area and determining their

properties, the soil scientists assigned the soils to

taxonomic classes (units). Taxonomic classes are concepts.

Each taxonomic class has a set of soil characteristics with

precisely defined limits. The classes are used as a basis for

comparison to classify soils systematically. The system of

taxonomic classification used in the United States is based

mainly on the kind and character of soil properties and the

arrangement of horizons within the profile (43). After the soil

scientists classified and named the soils in the survey area,

they compared the individual soils with similar soils in the

same taxonomic class in other areas so that they could

confirm data and assemble additional data based on

experience and research.

While a soil survey is in progress, samples of some of

the soils in the area generally are collected for laboratory

analyses and for engineering tests. Soil scientists interpret

the data from these analyses and tests as well as the fieldobserved characteristics and the soil properties to determine

the expected behavior of the soils under different uses.

Interpretations for all of the soils are field tested through

observation of the soils in different uses under different

levels of management. Some interpretations are modified to

fit local conditions, and some new interpretations are

developed to meet local needs. Data are assembled from

other sources, such as research information, production

records, and field experience of specialists. For example,

data on crop yields under defined levels of management are

assembled from farm records and from field or plot

experiments on the same kinds of soil.
Predictions about soil behavior are based not only or

soil properties but also on such variables as climate and

biological activity. Soil conditions are predictable over long

periods of time, but they are not predictable from year to

year. For example, soil scientists can predict with a fairly

high degree of accuracy that a given soil will have a high

water table within certain depths in most years, but they

cannot assure that a high water table will always be at a

specific level in the soil on a specific date.

After soil scientists located and identified the significant

natural bodies of soil in the survey area, they drew the

boundaries of these bodies on aerial photographs and

identified each as a specific map unit. Aerial photographs

show trees, buildings, fields, roads, and rivers, all of which

help in locating boundaries accurately.

Map Unit Composition

A map unit delineation on a soil map represents an area

dominated by one major kind of soil or an area dominated

by several kinds of soil. A map unit is identified and

named according to the taxonomic classification of the

dominant soil or soils. Within a taxonomic class there are

precisely defined limits for the properties of the soils. On

the landscape, however, the soils are natural objects. In

common with other natural objects, they have a

characteristic variability in their properties. Thus, the range

of some observed properties may extend beyond the limits

defined for a taxonomic class. Areas of soils of a single

taxonomic class rarely, if ever, can be mapped without

including

areas of soils of other taxonomic classes. Consequently,

every map unit is made up of the soil or soils for which it is

named and some soils that belong to other taxonomic

classes. These latter soils are called inclusions or included

soils.

Most inclusions have properties and behavioral patterns

similar to those of the dominant soil or soils in the map unit,

and thus they do not affect use and management. These are

called noncontrasting (similar) inclusions. They may or may

not be mentioned in the map unit descriptions. Other

inclusions, however, have properties and behavior divergent

enough to affect use or require different management. These

are contrasting (dissimilar) inclusions. They generally occupy

small areas and cannot be shown separately on the soil

maps because of the scale used in mapping. The inclusions

of contrasting soils are mentioned in the map unit

descriptions. A few inclusions may not have been observed

and consequently are not mentioned in the descriptions,

especially where the soil pattern was so complex that it was

impractical to make enough observations to identify all of

the kinds of soil on the landscape.

The presence of inclusions in a map unit in no way

diminishes the usefulness or accuracy of the soil data. The

objective of soil mapping is not to delineate pure taxonomic

classes of soils but rather to separate the landscape into

segments that have similar use and management

requirements. The delineation of such landscape segments

on the map provides sufficient information for the

development of resource plans, but onsite investigation is

needed to plan for intensive uses in small areas.
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, it 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

another 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.

Soil Descriptions

Soils on Flood Plains, Terraces, Deltas, and Tidal

Flats

These soils make up about 10 percent of the survey

area. They are level and nearly level. The native vegetation

is mainly trees and shrubs. Elevation is at or near sea level

to 300 feet above sea level. The average annual

precipitation is 30 to 60 inches, the average annual air

temperature is 48 to 52 degrees F, and the average frostfree season is 160 to 210 days.

These soils are very deep and are very poorly drained

to well drained. In many areas they have been artificially

drained. They formed in alluvium.

These soils are used mainly as hayland and pasture or

as cropland.

1. Mt. Vernon-Puyallup

Very deep, moderately well drained and well drained,

nearly level soils; on river terraces and flood plains

This map unit is in the western part of the survey

area, along the Nooksack River and its tributaries.

Slope is 0 to 2 percent. The native vegetation is mainly

conifers and shrubs. Elevation is 10 to 300 feet. The

average annual precipitation is 30 to 60 inches, the

average annual air temperature is 48 to 52 degrees F, and

the average frost-free season is 160 to 210 days.

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

is about 41 percent Mt. Vernon soils, 21 percent Puyallup

soils, and 38 percent soils of minor extent.

Mt. Vernon soils are moderately well drained. They

formed in alluvium with an admixture of volcanic ash in the

upper part. Typically, the surface layer is fine sandy loam.

The underlying material is stratified, mottled fine sandy

loam, very fine sandy loam, and sand.

Puyallup soils are well drained. They formed in alluvium.

Typically, the surface layer is fine sandy loam. The next

layer is loam and fine sandy loam. The underlying material

is sand.

Of minor extent in this unit are the somewhat

excessively drained Pilchuck and Snoqualmie soils and

Riverwash along the river channels, the somewhat

excessively drained Kline soils on alluvial fans, and the well

drained Larush soils on low river terraces along the South

and Middle Forks of the Nooksack River.

This unit is used as hayland and pasture or as cropland.

The main limitations in the areas used for hay and pasture

or for crops are the seasonal high water table in the Mt.

Vernon soils and a moderate available water capacity in the

Puyallup soils. The main limitations affecting homesite

development are the hazard of flooding on both soils and

the seasonal high water table in the Mt. Vernon soils. The

main limitations on sites for septic tank absorption fields

are the seasonal high water table in the Mt. Vernon soils

and a poor filtering capacity in the substratum of the

Puyallup soils.

2. Eliza-Tacoma

Very deep, very poorly drained, level soils that generally have

been artificially drained; on flood plains, deltas, and tidal flats

This map unit is in the southwestern part of the

survey area, along the Nooksack and Lummi Rivers.
Slope is 0 to 1 percent. The native vegetation is mainly

conifers and shrubs. Elevation is at or near sea level to 20

feet above sea level. The average annual precipitation is

30 to 40 inches, the average annual air temperature is 48

to 52 degrees F, and the average frost-free season is 160

to 210 days.

This unit makes up about 1 percent of the survey

area. It is about 70 percent Eliza soils, 25 percent

Tacoma soils, and 5 percent soils of minor extent.

Eliza soils are very poorly drained but in most areas

have been artificially drained. They formed in alluvium.

Typically, the surface layer is silt loam. The upper part of

the underlying material is mottled fine sandy loam. The

lower part is stratified, mottled silt loam and fine sandy

loam.

Tacoma soils are very poorly drained but in most areas

have been artificially drained. They formed in alluvium.

Typically, the surface layer is mottled silt loam. The upper

part of the underlying material also is mottled silt loam.

The lower part is mottled very fine sandy loam.

Of minor extent in this unit are the somewhat

excessively drained Neptune soils on marine terraces.

This unit is used mainly as hayland and pasture or as

cropland. Undrained soils are used as woodland or for

wildlife habitat.

The main limitations in the areas used for hay and

pasture or for crops are the seasonal high water table, the

salt influence, and the moderately slow permeability in the

Tacoma soils. The main limitations affecting homesite

development and septic tank absorption fields are the

hazard of flooding and the seasonal high water table in both

soils. The main limitations affecting timber harvesting are

the hazard of flooding and the muddiness caused by

seasonal wetness.

3. Briscot-Oridia

Very deep, poorly drained, nearly level soils that have

been artificially drained; on flood plains

This map unit is in the western part of the survey area,

along the Nooksack River and its tributaries. Slope is 0 to 2

percent. The native vegetation is mainly conifers and

shrubs. Elevation is 20 to 300 feet. The average annual

precipitation is 35 to 55 inches, the average annual air

temperature is 48 to 52 degrees F, and the average frostfree season is 160 to 190 days.

This unit makes up about 4 percent of the survey

area. It is about 37 percent Briscot soils, 25 percent

Oridia soils, and 38 percent soils of minor extent.

Briscot soils formed in alluvium. Typically, the surface

layer is silt loam. The underlying material is mottled silt

loam, very fine sandy loam, fine sandy loam, and fine sand.

Oridia soils formed in alluvium. Typically, the surface

layer is silt loam. The upper part of the underlying material

is mottled silt loam. The lower part is mottled very fine

sandy loam.

Of minor extent in this unit are the poorly drained

Bellingham soils and Puget, Snohomish, and Sumas

soils that have been drained.

This unit as used as hayland and pasture or as

cropland (fig. 2). The main limitation in the areas used for

hay and pasture or for crops is the seasonal high water

table. The main limitations affecting homesite

development and septic tank absorption fields are the

hazard of flooding and the seasonal high water table.

Soils on Outwash Terraces, Moraines, and Till Plains

These soils make up about 22 percent of the survey

area. They are level to very steep. The native vegetation is

mainly trees and shrubs. Elevation is at or near sea level

to 1,200 feet above sea level. The average annual

precipitation is 35 to 75 inches, the average air

temperature is 45 to 52 degrees F, and the average frostfree season is 150 to 210 days.

These soils are deep and very deep and are very poorly

drained to somewhat excessively drained. Most of the very

poorly drained areas have been artificially drained. The

soils formed dominantly in alluvium, loess, volcanic ash,

organic deposits, glacial outwash, and glaciofluvial

deposits.

These soils are used mainly as hayland and pasture, as

cropland, or as woodland. They also are used as sites for

homes and as a source of aggregate.

4. Kickerville-Barneston-Everett

Very deep and deep, well drained and somewhat excessively

drained, level to very steep soils; on outwash terraces and

moraines

This map unit is on outwash terraces and terrace

escarpments throughout the survey area. Slope is 0 to 60

percent. The native vegetation is mainly conifers and

shrubs. Elevation is 50 to 1,200 feet. The average annual

precipitation is 35 to 75 inches, the average annual air

temperature is 45 to 52 degrees F, and the average frostfree season is 150 to 210 days.

This unit makes up about 9 percent of the survey area.

It is about 27 percent Kickerville soils, 24 percent

Barneston soils, 19 percent Everett soils, and 30 percent

soils of minor extent.

Kickerville soils are very deep and well drained. They

formed in a mixture of loess and volcanic ash over glacial

outwash. They are on outwash terraces. Typically, the

surface layer is silt loam. The upper part of the subsoil also

is silt loam, and the lower part is very gravelly loam. The

substratum is extremely
Figure 2.-A pastured area of the Briscot-Oridia general soil map unit is in the foreground. The wooded foothills in the background are in the

Vanzandt-Squires and Montborne-Rinker general soil map units.

gravelly sand and very gravelly sand.

Barneston soils are very deep and somewhat

excessively drained. They formed in a mixture of loess

and volcanic ash over glacial outwash. They are on

outwash terraces and terrace escarpments. Typically, the

surface layer is gravelly loam. The subsoil is very

gravelly loam. The substratum is extremely gravelly sand.

Everett soils are very deep and deep and are

somewhat excessively drained. They formed in a mixture

of volcanic ash and alluvium over glacial outwash and

glacial till. They are on outwash terraces and moraines.

Typically, the surface layer and subsoil are very gravelly

sandy loam. The substratum is very

gravelly and extremely gravelly sand. In some areas

dense glacial till is at a depth of 40 to 60 inches.

Of minor extent in this unit are the well drained Winston

soils, mainly in the Columbia Valley; the somewhat poorly

drained Clipper soils in depressions on outwash plains; and

the well drained Barnhardt soils southwest of Everson.

This unit is used mainly as hayland and pasture, as

woodland, or as cropland. It also is used as a site for

homes and as a source of aggregate.

The main limitations in the areas used for hay and

pasture or for crops are a low available water capacity and

very gravelly surface layer in the Everett soils. The,

Kickerville soils are well suited to hay and pasture and
to cropland. All three soils are well suited to woodland.

The main limitation affecting homesite development is the

slope in some areas. Other limitations are the

seasonal high water table and depth to the dense glacial till

in some areas of the. Everett soils. The main limitation on

sites for septic tank absorption fields is a poor filtering

capacity in the substratum of all the major soils.

5. Lynden-Hale-Tromp

Very deep, well drained to somewhat poorly drained,

level to gently sloping soils; on outwash terraces

This map unit is in the western part of the survey area.

Slope is 0 to 8 percent. The native vegetation is mainly

conifers and shrubs. Elevation is 50 to 300 feet. The

average annual precipitation is 40 to 55 inches, the

average annual air temperature is 48 to 52 degrees F, and

the average frost-free season is 150 to 190 days.

This unit makes up about 10 percent of the survey area.

It is about 23 percent Lynden soils, 21 percent Hale soils,

17 percent Tromp soils, and 39 percent soils of minor

extent.

Lynden soils are well drained.' They formed in volcanic

ash and loess over glacial outwash on outwash terraces.

Typically, the surface layer and subsoil are sandy loam. The

substratum is sand.

Hale soils are somewhat poorly drained but in most

areas have been artificially drained. They formed in an

admixture of loess and volcanic, ash over glacial outwash

on outwash terraces. Typically, the surface layer is silt

loam. The subsoil is mottled loam. The upper part of the

substratum is mottled loamy fine sand. The lower part is

sand.

Tromp soils are moderately well drained. They formed in

a mixture of volcanic ash and loess over glacial outwash

on outwash terraces. Typically, the surface layer is loam.

The upper part of the subsoil also is loam. The lower part

is weakly cemented, mottled sand. The substratum is

mottled sand.

Of minor extent in this unit are the somewhat poorly

drained Edmonds soils, the moderately well drained Laxton

soils, the poorly drained Woodlyn soils, the somewhat

excessively drained Lynnwood soils, the moderately well

drained Yelm soils adjacent to soils that formed in

glaciomarine drift, and the artificially drained Everson soils.

This unit is used mainly as hayland and pasture or as

cropland (fig. 3). It also is used as woodland and as a site

for homes.

The main limitations in the areas used for hay and

pasture or for crops are the seasonal high water table in

the Hale and Tromp soils and a moderate available water

capacity in the Lynden and Hale soils. The main

limitation affecting timber harvesting is the muddiness

caused by seasonal wetness in the Hale soils. The main

limitation affecting homesite development and septic tank

absorption fields are the seasonal high water table in the

Hale and Tromp soils and a poor filtering capacity in the

substratum of all the major soils. Lynden soils are well

suited to homesite development.

6. Pangborn-Fishtrap-Shalcar

Very deep, very poorly drained, nearly level soils that have

been artificially drained; in depressions on outwash terraces,

till. plains, and stream terraces

This map unit is in depressions on outwash terraces. It is

in the western part of the survey area. Slope is 0 to 2

percent. The native vegetation is mainly conifers and shrubs.

Elevation is at or near sea level to 600 feet above sea level.

The average annual precipitation is 35 to 55 inches, the

average annual air temperature is 48 to 52 degrees F, and

the average frost-free season is 150 to 190 days.

This unit makes up about 3 percent of the survey area.

It is about 52 percent Pangborn soils, 16 percent Fishtrap

soils, 16 percent Shalcar soils, and 16 percent soils of minor

extent.

Pangborn soils formed in herbaceous and woody

organic deposits in depressions on outwash terraces.

Typically, the surface layer is muck. The underlying

material also is muck.

Fishtrap soils formed in herbaceous and woody organic

deposits over glaciofluvial deposits in depressions on

outwash terraces. Typically, the surface layer is muck. The

upper part of the underlying material also is muck. The

lower part is mottled sand.

Shalcar soils formed in herbaceous and woody organic

deposits over glaciofluvial deposits on outwash terraces, till

plains, and stream terraces. Typically, the surface layer is

muck. The upper part of the underlying material is loam.

The lower part is gravelly sand.

Of minor extent in this unit are the poorly drained

Bellingham, Snohomish, and Puget soils and the

somewhat poorly drained Hale soils.

This unit is used mainly as hayland and pasture or as

cropland. Undrained soils are used as woodland.

The main limitation in the areas used for hay and

pasture or for crops is the seasonal high water table. The

main limitations affecting homesite development are the

seasonal high water table and low strength of the soils.

The main limitation on sites for septic tank absorption

fields is the seasonal high water table.

Soils on Glaciomarine Drift Plains and Terraces

These soils make up about 17 percent of the survey

area. They are level to very steep. The native
Figure 3.-An area of the Lynden-Hale-Tromp general soil map unit used as pasture.

vegetation is mainly trees and shrubs. Elevation is 20 to

600 feet. The average annual precipitation is 30 to 55

inches, the average annual air temperature is 48 to 52

degrees F, and the average frost-free season is 150 to 200

days.

These soils are very deep and are poorly drained to

moderately well drained. Some areas have been

artificially drained. The soils formed in alluvium, loess,

volcanic ash, glaciomarine drift, glaciofluvial deposits, and

glaciolacustrine sediments.

These soils are used mainly as hayland and pasture.

They also are used as cropland and woodland.

7. Whatcom-Labounty

Very deep, moderately well drained and poorly drained,

level to very steep soils; dominantly on glaciomarine drift

plains

This map unit is in the western part of the survey

area. Slope is 0 to 60 percent. The native vegetation is

mainly conifers and shrubs. Elevation is 50 to 600 feet.

The average annual precipitation is 35 to 55 inches, the

average annual air temperature is 48 to 52. degrees F, and

the average frost-free season is 150 to 190 days.

This unit makes up about 12 percent of the survey area.

It is about 72 percent Whatcom soils, 24 percent Labounty

soils, and 4 percent soils of minor extent.

Whatcom soils are moderately well drained. They

formed in a mixture of loess and volcanic ash over

glaciomarine drift. Typically, the surface layer is silt loam.

The upper part of the subsoil also is silt loam. The lower

part is mottled loam. The substratum also is mottled loam.

Labounty soils are poorly drained. In some areas

they have been artificially drained. They formed in

glaciomarine drift with an admixture of loess and

volcanic ash. Typically, the surface layer is silt loam.

The subsoil and substratum are mottled loam.

Of minor extent in this unit are the poorly drained

Bellingham soils, the very poorly drained Histosols, and

Urban land.
This unit is used mainly as hayland and pasture or as

woodland. It also is used as cropland and as a site for

homes.

The main limitations in the areas used for hay and

pasture or for crops are the seasonal high water table and

slow permeability in the substratum. The main limitation in

the areas used as woodland is the muddiness caused by

seasonal wetness. The main limitations affecting homesite

development and septic tank absorption fields are the

seasonal high water table in both soils, moderately slow

permeability in the Labounty soils, and the slope of the

Whatcom soils.

8. Birchbay-Whitehorn

Very deep, moderately well drained and poorly drained,

level to gently sloping soils; on glaciomarine drift plains

This map unit is near Lake Terrell on wave-reworked

glaciomarine drift plains in the extreme western part of the

survey area. Slope is 0 to 8 percent. The native vegetation

is mainly conifers and shrubs. Elevation is

50 to 350 feet. The average annual precipitation is 30 to 40

inches, the average annual air temperature is 48 to 52

degrees F, and the average frost-free season is 160 to 200

days.

This unit makes up about 3 percent of the survey

area. It is about 48 percent Birchbay soils, 42 percent

Whitehorn soils, and 10 percent soils of minor extent.

Birchbay soils are moderately well drained. They formed

in an admixture of loess and volcanic ash over glaciofluvial

deposits and glaciomarine drift. These soils are on the

higher parts of the wave-reworked glaciomarine drift plains.

Typically, the surface layer is silt loam. The upper part of

the subsoil also is silt loam. The lower part is gravelly silt

loam. The upper part of the substratum is very gravelly

sand. The lower part is mottled loam.

Whitehorn soils are poorly drained. They formed in

volcanic ash, loess, glaciofluvial deposits, and glaciomarine

drift. These soils are in depressions on wave-reworked

glaciomarine drift plains. Typically, the surface layer is silt

loam. The upper part of the subsoil is loam and very fine

sandy loam. The lower part is very gravelly sandy loam.

The upper part of the substratum is mottled loam. The lower

part is mottled silt loam.

Of minor extent in this unit are the moderately well

drained Whatcom soils, the well drained Kickerville soils on

terraces, and the poorly drained Labounty soils.

This unit is used mainly as hayland and pasture or as

woodland. It also is used as cropland and as a site for

homes.

The main limitations in the areas used for hay and

pasture or for crops are the seasonal high water table

and the ponding on the Whitehorn soils. The main

limitation affecting woodland is the muddiness caused by

seasonal wetness. The main limitations affecting homesite

development and septic tank absorption fields are the

seasonal high water table and the slow permeability in the

substratum.

9. Skipopa-Bellingham

Very deep, somewhat poorly drained and poorly drained,

level to gently sloping soils; on terraces

This map unit is in the western part of the survey area,

mainly in an area north of Everson and in another area

east of Birch Bay. Slope is 0 to 8 percent. The native

vegetation is trees and shrubs. Elevation is 20 to 300 feet.

The average annual precipitation is 30 to 50 inches, the

average annual air temperature is 48 to 52 degrees F, and

the average frost-free season is 160 to 200 days.

This unit makes up about 2 percent of the survey

area. It is about 51 percent Skipopa soils, 41 percent

Bellingham soils, and 8 percent soils of minor extent.

Skipopa soils are somewhat poorly drained. They

formed in volcanic ash and loess over glaciolacustrine

sediments on the higher parts of the undulating terraces.

Typically, the surface layer is silt loam. The upper part of

the subsoil also is silt loam. The lower part is mottled silty

clay loam. The substratum also is mottled silty clay loam.

Bellingham soils are poorly drained. They formed in an

admixture of loess, alluvium, and lacustrine deposits in

depressions on undulating terraces. Typically, the surface

layer is silty clay loam. The subsoil and substratum are

mottled silty clay loam.

Of minor extent in this unit are Urban land and the

poorly drained Blainegate soils near the town of Blaine.

This unit is used mainly as hayland and pasture. It also

is used as woodland, as cropland, and as a site for homes.

The main limitations in the areas used for hay and

pasture or for crops are the seasonal high water table and

the very slow permeability in the substratum. The main

limitation in the areas used as woodland is the muddiness

caused by seasonal wetness. The main limitations affecting

homesite development and septic tank absorption fields are

the seasonal high water table and the very slow

permeability in the substratum.

Soils on Foothills, Low Mountains, Plateaus, and

Landslides

These soils make up about 21 percent of the survey

area. They are gently sloping to very steep. The native

vegetation is mainly conifers and shrubs. Elevation is 100

to 1,600 feet. The average annual precipitation is 35 to 70

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

140 to 200 days.

These soils are moderately deep to very deep and are

moderately well drained and well drained. They formed

dominantly in loess, volcanic ash, colluvium, and slope

alluvium, in material weathered from phyllite, sandstone,

and metasedimentary rocks, and in glacial drift.

These soils are used mainly as woodland.

10. Vanzandt-Squires

Moderately deep, moderately well drained and well

drained, gently sloping to very steep soils; dominantly on

low mountains and foothills

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

area. Slope is 5 to 60 percent. The native vegetation is

mainly conifers and shrubs. Elevation is 250 to 1,500 feet.

The average annual precipitation is 45 to 70 inches, the

average annual air temperature is 45 to 50 degrees F, and

the average frost-free season is 140 to 180 days.

This unit makes up about 3 percent of the survey area.

It is about 45 percent Vanzandt soils, 33 percent Squires

soils, and 22 percent soils of minorextent.

Vanzandt soils are moderately well drained. They formed

in volcanic ash, loess, and slope alluvium over glacial till

derived dominantly from phyllite. They are on low

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

organic material. The surface layer is very gravelly loam.

The subsoil also is very gravelly loam. The substratum is

mottled very gravelly loam. Dense glacial till is at a depth of

31 inches. Depth to the dense glacial till ranges from 20 to

40 inches.

Squires soils are well drained. They formed in a mixture

of volcanic ash, loess, glacial till, and colluvium derived

dominantly from phyllite. They are on foothills and low

mountain back slopes and toe slopes. Typically, the

surface is covered with a mat of organic material. The

surface layer is very channery silt loam. The subsoil is very

channery loam. The substratum is very channery sandy

loam. Phyllite is at a depth of 30 inches. Depth to the

phyllite ranges from 20 to 40 inches.

Of minor extent in this unit are the well drained Heisler

soils east and south of Vanzandt Dike and Wickersham and

Wiseman soils on alluvial fans and terraces in the valley of

the South Fork of the Nooksack River.

This unit is used as woodland. The main limitations

affecting timber harvesting are the slope and the

muddiness caused by seasonal wetness.

11. Squalicum-Chuckanut-Nati

Moderately deep to very deep, moderately well drained and

well drained, gently sloping to very steep soils; on foothills,

plateaus, and landslides

This map unit is on foothills in the eastern and

southern parts of the survey area. Slope is 3 to 60

percent. The native vegetation is mainly conifers and

shrubs. Elevation is 100 to 1,600 feet. The average annual

precipitation is 35 to 60 inches, the average annual air

temperature is 45 to 50 degrees F, and the average frostfree season is 140 to 200 days.

This unit makes up about 18 percent of the survey area.

It is about 24 percent Squalicum soils, 16 percent

Chuckanut soils, 15 percent Nati soils, and 45 percent soils

of minor extent.

Squalicum soils are deep and moderately well drained.

They formed in a mixture of volcanic ash, loess, and slope

alluvium over glacial till. They are on foothills. Typically, the

surface is covered with a mat of organic material. The

surface layer is loam. The upper part of the subsoil also is

loam. The lower part is gravelly loam. The substratum also

is gravelly loam. Dense glacial till is at a depth of 44 inches.

Depth to the dense glacial till ranges from 40 to 60 inches.

Chuckanut soils are very deep and deep and are well

drained. They formed in a mixture of volcanic ash and

colluvium derived from glacial drift and sandstone. They are

on foothills and landslides. Typically, the surface layer is

loam. The subsoil is sandy loam and gravelly loam. The

substratum is gravelly sandy loam. Some Chuckanut soils

have sandstone at a depth of 40 to 60 inches.

Nati soils are moderately deep and well drained. They

formed in colluvium and slope alluvium derived from

sandstone and siltstone with an admixture of volcanic ash

and glacial till. They are on foothills and plateaus. Typically,

the surface is covered with a mat of organic material. The

surface layer and the subsoil are loam. The substratum is

fine sandy loam. Sandstone is at a depth of 31 inches.

Depth to the sandstone ranges from 20 to 40 inches.

Of minor extent in this unit are the well drained Andic

Xerochrepts on extremely steep slopes, the well drained

Blethen soils, and the moderately well drained Sehome soils.

Also of minor extent are the moderately well drained Comar

soils north of Deming, the well drained Pickett soils on

Lummi Island, the very poorly drained Shalcar soils, and

Rock outcrop.

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

hayland and pasture and as a site for homes.

Erosion is a hazard in the areas used for hay and
pasture. The main limitations affecting timber harvesting are

the slope on part of the unit and the muddiness caused by

seasonal wetness. The main limitations affecting homesite

development and septic tank absorption fields are the

slope, the moderate depth to bedrock or dense glacial till,

and the seasonal high water table in the Squalicum soils.

Soils on Mountains, Plateaus, and Ridges

These soils make up about 12 percent of the survey

area. They are gently sloping to very steep. The native

vegetation is conifers and shrubs. Elevation is 1,000 to

2,500 feet. The average annual precipitation is 45 to 85

inches, the average annual air temperature is 41 to 45

degrees F, and the average frost-free season is 100 to 150

days.

These soils are moderately deep and very deep and are

moderately well drained and well drained. They formed in

volcanic ash, colluvium, and slope alluvium, in material

weathered from phyllite, sandstone, and metasedimentary

rocks, and in glacial drift.

These soils are used mainly as woodland.

12. Montborne-Rinker

Moderately deep, moderately well drained and well

drained, gently sloping to very steep soils; on mountain

back slopes, shoulder slopes, and plateaus

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

area. Slope is 5 to 60 percent. The native vegetation is

mainly conifers and shrubs. Elevation is 1,000 to 2,000

feet. The average annual precipitation is 60 to 80 inches,

the average annual air temperature is 41 to 45 degrees F,

and the average frost-free season is 100 to 150 days.

This unit makes up about 3 percent of the survey area.

It is about 48 percent Montborne soils, 25 percent Rinker

soils, and 27 percent soils of minor extent.

Montborne soils are moderately well drained. They

formed in an admixture of volcanic ash, loess, colluvium,

and slope alluvium over glacial till derived dominantly from

phyllite. They are on mountain back slopes and plateaus.

Typically, the surface is covered with a mat of organic

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

very gravelly loam. The substratum is extremely gravelly

sandy loam. Dense glacial till is at a depth of 33 inches.

Depth to the dense glacial till ranges from 20 to 40 inches.

Rinker soils are well drained. They formed in a mixture

of volcanic ash, colluvium, and slope alluvium derived

dominantly from phyllite. They are on mountain back slopes

and shoulder slopes. Typically, the surface

is covered with a mat of organic material. The surface

layer is very channery silt loam. The subsoil is very

channery silt loam and extremely channery silt loam. The

substratum is extremely channery loam. Phyllite is at a

depth of 30 inches. Depth to the phyllite ranges from 20 to

40 inches.

Of minor extent in this unit are the well drained

Sandun and Sorensen soils. Sandun soils formed in

dunite-influenced material along the Middle Fork of the

Nooksack River.

This unit is used as woodland. The main limitations

affecting timber harvesting are the slope and the

muddiness caused by seasonal wetness.

13. Oakes-Revel

Very deep and moderately deep, well drained, gently

sloping to very steep soils; on mountain back slopes,

ridges, and plateaus

This map unit is in the eastern and southern parts of the

survey area. Slope is 5 to 80 percent. The native

vegetation is conifers and shrubs. Elevation is 1,000 to

2,500 feet. The average annual precipitation is 45 to 85

inches, the average annual air temperature is 41 to 45

degrees F, and the average frost-free season is 100 to 150

days.

This unit makes up about 9 percent of the survey

area. It is about 40 percent Oakes soils, 13 percent

Revel soils, and 47 percent soils of minor extent.

Oakes soils are very deep. They formed in volcanic

ash, colluvium, and slope alluvium derived from glacial

drift. They are on mountain back slopes. Typically, the

surface is covered with a mat of organic material. The

surface layer and the upper part of the subsoil are very

gravelly loam. The lower part is extremely gravelly sandy

loam. The substratum is extremely cobbly fine sandy loam.

Revel soils are moderately deep. They formed in a

mixture of volcanic ash, colluvium, and slope alluvium

derived dominantly from sandstone, siltstone, and glacial

till. They are on mountain back slopes, ridges, and

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

organic material. The surface layer and subsoil are loam.

The substratum is sandy loam. Sandstone is at a depth of

35 inches. Depth to the sandstone ranges from 20 to 40

inches.

Of minor extent in this unit are the well drained Andic

Xerochrepts on extremely steep slopes, the moderately well

drained Cupples soils, the somewhat excessively drained

Skykomish soils, the well drained Welcome soils, and Rock

outcrop.

This unit is used as woodland. The main limitations
affecting timber harvesting are the slope and occasional

snowpack.

Soils on High Mountains, Plateaus, and Ridges

These soils make up about 18 percent of the survey

area. They are gently sloping to extremely steep. The

native vegetation is conifers and shrubs. Elevation is 1,800

to 5,500 feet. The average annual precipitation is 70 to 105

inches, the average annual air temperature is 40 to 43

degrees F, and the average frost-free season is 80 to 110

days.

These soils are shallow to very deep and are

moderately well drained and well drained. They formed

dominantly in volcanic ash, loess, slope alluvium, and

colluvium over glacial till derived from sandstone, phyllite,

dunite, and serpentine.

These soils are used mainly as woodland.

14. Getchell-Kindy-Potchub

Moderately deep, moderately well drained, gently sloping to

very steep soils; on high mountains, plateaus, and ridges

This map unit is in the northeastern part of the survey

area. Slope is 3 to 60 percent. The native vegetation is

conifers and shrubs. Elevation is 1,800 to 4,500 feet. The

average annual precipitation is 70 to 105 inches, the

average annual air temperature is 40 to 43 degrees F, and

the average frost-free season is 80 to 110 days.

This unit makes up about 5 percent of the survey

area. It is about 30 percent Getchell soils, 30 percent

Kindy soils, 20 percent Potchub soils, and 20 percent soils

of minor extent.

Getchell soils formed in an admixture of volcanic ash

and colluvium over glacial till. They are on high mountains

and plateaus. Typically, the surface is covered with a mat

of organic material. The surface layer is loam. The subsoil

is sandy loam. Dense glacial till is at a depth of 36 inches.

Depth to the dense glacial till ranges from 20 to 40 inches.

Kindy soils formed in a mixture of volcanic ash,

loess, and colluvium over glacial till. They are on high

mountains and plateaus. Typically, the surface is covered

with a mat of organic material. The surface layer is gravelly

silt loam. The upper part of the subsoil is very gravelly silt

loam. The lower part is very gravelly loam. Dense glacial till

is at a depth of 25 inches. Depth to the dense glacial till

ranges from 20 to 40 inches.

Potchub soils formed in an admixture of volcanic ash,

loess, and colluvium over glacial till. They are on high

mountains and ridges. Typically, the surface is covered with

a mat of organic material. The surface layer is loam. The

subsoil is gravelly loam and gravelly sandy

loam. Dense glacial till is at a depth of 39 inches. Depth to

the dense glacial till ranges from 20 to 40 inches.

Of minor extent in this unit are the Hartnit, Saar, Oso,

Gallup, and Shuksan soils. Also of minor extent are

Clendenen, Deming, Kulshan, and Hozomeen soils and

Rock outcrop.

This unit is used as woodland. The main limitations

affecting timber harvesting are the slope and snowpack.

15. Hinker-Crinker-Springsteen

Moderately deep, well drained, moderately steep to very

steep soils; on high mountains

This map unit is in the southeastern part of the survey

area. Slope is 15 to 60 percent. The native vegetation is

conifers and shrubs. Elevation is 1,800 to 4,200 feet. The

average annual precipitation is 70 to 105 inches, the

average annual air temperature is 40 to 43 degrees F, and

the average frost-free season is 80 to 110 days.

This unit makes up about 3 percent of the survey

area. It is about 34 percent Hinker soils, 25 percent

Crinker soils, 20 percent Springsteen soils, and 21

percent soils of minor extent.

Hinker soils formed in a mixture of volcanic ash, loess,

and colluvium derived dominantly from phyllite. Typically,

the surface is covered with a mat of organic material. The

surface layer is very channery silt loam. The upper part of

the subsoil is very cobbly silt loam. The lower part is very

channery silt loam. Phyllite is at a depth of 21 inches.

Depth to the phyllite ranges from 20 to 40 inches.

Crinker soils formed in an admixture of volcanic ash,

slope alluvium, colluvium, and glacial till derived dominantly

from phyllite. Typically, the surface is covered with a mat of

organic material. The surface layer is very channery silt

loam. The subsoil is also very channery silt loam. Phyllite is

at a depth of 24 inches. Depth to the phyllite ranges from

20 to 40 inches.

Springsteen soils formed in a mixture of volcanic ash,

colluvium, and glacial till derived from phyllite. Typically, the

surface is covered with a mat of organic material. The

surface layer is very gravelly loam. The subsoil also is very

gravelly loam. Phyllite is at a depth of 24 inches. Depth to

the phyllite ranges from 20 to 40 inches.

Of minor extent in this unit are the moderately well

drained Wollard and Diobsud soils that formed in glacial till

and the shallow Hannegan soils. Also of minor extent are

some small areas of Typic Cryorthods and Kindy, Saar,

Hozomeen, and Klawatti soils. Soils of minor extent make

up about 25 percent of the unit.

This unit is used as woodland. The main limitations

affecting timber harvesting are the slope and snowpack.
16. Edfro-Klawatti-Twinsi

Shallow and moderately deep, moderately well drained and

well drained, moderately steep to very steep soils; on high

mountains

This map unit is dominantly in the southeastern part of

the survey area, adjacent to Twin Sisters Mountain with a

small serpentine area on Sumas Mountain. Slope is 15 to

60 percent. The native vegetation is conifers and shrubs.

Elevation is 2,000 to 4,300 feet. The average annual

precipitation is 90 to 100 inches, the average annual air

temperature is 41 to 43 degrees F, and the average frostfree season is 90 to 105 days.

This unit makes up about 2 percent of the survey

area. It is about 26 percent Edfro soils, 25 percent

Klawatti soils, 20 percent Twinsi soils, and 29 percent

soils of minor extent.

Edfro soils are shallow and moderately well drained.

They formed in a mixture of volcanic ash, loess, and

colluvium over glacial till derived dominantly from dunite.

Typically, the surface is covered with a mat of organic

material. The surface layer is very gravelly silt loam. The

upper part of the subsoil is extremely gravelly silt loam.

The lower part is extremely gravelly loam. Dense glacial till

is at a depth of 19 inches. Depth to the dense glacial till

ranges from 14 to 20 inches.

Klawatti soils are moderately deep and well drained.

They formed in volcanic ash, slope alluvium, and colluvium

derived dominantly from dunite and serpentine. Typically,

the surface is covered with a mat of organic material. The

surface layer is very gravelly silt loam. The subsoil is

extremely gravelly silt loam. Dunite is at a depth of 25

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

Twinsi soils are moderately deep and moderately well

drained. They formed in colluvium and glacial till with an

admixture of volcanic ash and loess. The colluvium and

glacial till are dominantly derived from dunite. Typically, the

surface is covered with a mat of organic material. The

surface layer is very gravelly loam. The subsoil also is very

gravelly loam. The substratum is very gravelly sandy loam.

Dense glacial till is at a depth of 27 inches. Depth to the

dense glacial till ranges from 20 to 40 inches.

Of minor extent are the very deep, well drained

Jackman soils and the very deep, somewhat excessively

drained Jorgenson soils. These soils make up about 25

percent of the unit. Also included are the Kindy,

Hozomeen, and Saar soils, Rock outcrop, and Rubble land.

This unit is used as woodland. The main limitations

affecting the timber harvesting are the slope and

snowpack.

17. Rock Outcrop-Typic Cryorthods-Andic

Cryochrepts

Moderately deep to very deep, well drained, very steep

soils; on high mountains and ridges

This map unit is in the northeastern part of the survey

area. Slope is 60 to 100 percent. The native vegetation is

conifers and shrubs. Elevation is 1,800 to 5,500 feet. The

average annual precipitation is 70 to 105 inches, the

average annual air temperature is 40 to 43 degrees F, and

the average frost-free season is 80 to 110 days.

This unit makes up about 8 percent of the survey area. It

is about 29 percent Rock outcrop, 24 percent Typic

Cryorthods, 13 percent Andic Cryochrepts, and 34 percent

soils of minor extent.

Rock outcrop is dominantly sandstone. It is hard and

mostly unweathered. It occurs as steep cliffs and irregular

formations.

Typic Cryorthods formed in volcanic ash, colluvium and

residuum from sandstone, and glacial till derived from

phyllite. Commonly, the surface layer, subsoil, and

substratum are loam. The texture, content of rock

fragments, and depth to glacial till or bedrock vary widely

within short distances.

Andic Cryochrepts formed in a mixture of volcanic ash,

glacial till, and colluvium derived dominantly from

sandstone. Commonly, the surface is covered with a mat of

organic material. The surface layer, subsoil, and

substratum are very gravelly loam. The texture, content of

rock fragments, and depth to dense glacial till or bedrock

vary widely within short distances.

Of minor extent in this unit are the Kulshan, Shuksan,

Gallup, and Hartnit soils. Also of minor extent are Kindy,

Oso, Getchell, Saar, and Potchub soils.

This unit is used as woodland. The main limitations

affecting timber harvesting are the slope and snowpack.

Broad Land Use Considerations

The soils in the survey area vary widely in their potential

for major land uses. Approximately 15 percent of the survey

area is used for cultivated crops, mainly berries, potatoes,

and truck crops. This cropland is in the western part of the

survey area and is concentrated in general soil map units 1

through 6. The soils in these map units have high potential

for crops. The soils in units 1, 2, and 3, however, are

occasionally flooded, generally in winter and spring. The

flooding causes slight or moderate crop damage. Wetness

is the main limitation. The main soils used for cultivated

crops in units 1, 2, and 3 are Mt. Vernon, Briscot, Puyallup,

Oridia, and Eliza soils. The soils in units 4 and 5 are on

outwash terraces. A low or moderate available water
capacity and the seasonal high water table are the main

limitations. The main soils used for cultivated crops in units

4 and 5 are Kickerville, Lynden, Hale, and Tromp soils. The

Pangborn, Fishtrap, and Shalcar soils in unit 6 are in

depressions on outwash terraces. The high water table is

the main limitation.

Approximately 20 percent of the survey area is used for

pasture. Units 1 through 9 have high potential for grasses

and legumes. Examples of soils used for pasture are Mt.

Vernon, Briscot, Puyallup, and Oridia soils on flood plains;

Kickerville, Hale, Tromp, and Pangborn soils on outwash

terraces; and Whatcom, Labounty, Birchbay, Whitehorn,

Skipopa, and Bellingham soils on glaciomarine drift plains

and lacustrine terraces. The main limitations in units 7, 8,

and 9 are the seasonal high water table and slow

permeability in the substratum. The main limitation in units

4 and 5 and in the Puyallup soils in unit 1 is a low or

moderate available water capacity. Grazing should be

restricted in winter and spring, when the soils are saturated.

About 62 percent of the survey area is used as

woodland. The productivity for conifers ranges from low to

high. The soils in units 10 through 13 can produce the

largest amount of wood, especially Squalicum, Oakes,

Chuckanut, and Nati soils. Units 4, 5, 7, 8, 14, 15, 16, and

17 also can produce large amounts of wood. The main soils

used for woodland are Barneston, Shuksan, Kindy,

Getchell, Everett, Whatcom, and Birchbay soils. The use of

equipment is restricted on most soils during wet periods.

The main limitation affecting timber harvesting is snowpack

in units 12, 13, 14, 15, 16, and 17. The slope and the

muddiness caused by seasonal wetness are limitations in

all of the units. Plant competition is generally the most

serious hazard, although seedling mortality is the main

hazard in unit 14. The hazard of windthrow on most soils

and the hazard of erosion on the steeper slopes also are

important management concerns.

About 15,000 acres, or 3 percent of the county, is used

as urban or built-up land. The main built-up areas are in

units 4, 5, 7, 8, and 11. In more than 70 percent of the

survey area, the soils have severe limitations as sites for

septic tank absorption fields. The Whatcom, Labounty,

Birchbay, and Whitehorn soils in units 7 and 8 are used as

sites for homes. The main limitations in these units are the

seasonal high water table and the slow permeability in the

substratum. The Squalicum, Chuckanut, Lynden, Everett,

and Kickerville soils in units 4, 5, and 11 are used as sites

for homes. The main limitations in these units are the

seasonal high water table and the depth to dense glacial

till in the

Squalicum and Everett soils, the depth to bedrock in the

Chuckanut soils, and the slope of the Chuckanut, Everett,

and Squalicum soils. In the other units in the survey area,

wetness, the slope, the hazard of flooding, a poor filtering

capacity in the substratum, the depth to bedrock, and low

strength are the principal limitations.

The potential for recreational uses is low to high,

depending on the intensity of the expected use and the

properties of the soil. Most of the soils in units 4, 5, and 6

have high potential for intensive recreational uses. Most of

the lakes in Whatcom County are located in these map

units. Units 1, 2, and 3 usually have low potential for

recreational uses because the soils are subject to flooding.

The potential is high, however, in the summer. The slope in

units 7 through 14 is a limitation in intensively used

recreational areas, such as playgrounds and camp areas.

All of these units, however, are suitable for extensive

recreational areas, such as those used for hiking,

horseback riding, hunting, fishing, and motorbiking. Small

areas that are suited to intensive development are available

in most of the map units.

In all of the units, except for unit 14, the potential for

openland wildlife habitat is moderate or high and the

potential for woodland wildlife habitat is high. Unit 14 has

low potential for openland wildlife habitat and moderate

potential for woodland wildlife habitat. The well-being of

wildlife is largely determined by the quantity and quality of

the habitat elements produced on the soils managed for

woodland, pasture, or cultivated crops. The soils on the

flood plains in units 1, 2, and 3, the organic soils in unit 6,

and the soils in level areas of units 4, 5, 7, 8, and 9 have

high potential for wetland wildlife habitat.

Timber management practices that improve woodland

wildlife habitat include establishing scattered, small,

irregularly shaped open areas among the trees; maintaining

snags; maintaining uneven-aged stands of mixed species;

and protecting riparian vegetation and the water quality in

streams.

Conservation practices that improve openland wildlife

habitat include growing cover crops, maintaining abundant

crop residue during winter, leaving uncultivated strips of

vegetation along shorelines and streambanks, ensuring

proper grazing of pasture, closely regulating livestock use in

streams and on wetlands, and controlling runoff of animal

waste.

Wetland habitat can be maintained or improved by

protecting riparian vegetation from cultivation, fire,

herbicides, and excessive grazing; by protecting

wetlands from excessive sedimentation; and by ensuring

that the wetlands are not drained.
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, depth to bedrock, wetness, temperature,

degree of drainage, 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, Chuckanut loam, bedrock

substratum, 5 to 15 percent slopes, is a phase of the

Chuckanut series.

Some map units are made up of two or more major

soils. These map units are called soil complexes or

undifferentiated groups.

A soil complex consists of two or more soils, or one or

more soils and a miscellaneous area, 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. EdmondsWoodlyn loams, drained, 0 to 2 percent slopes, is an

example.

An undifferentiated group is made up of two or more soils

that could be mapped individually but are mapped as one

unit because similar interpretations can be made for use and

management. The pattern and proportion of the soils in the

mapped areas are not uniform. An area can be made up of

only one of the major soils, or it can be made up of all of

them. Shalcar and Fishtrap soils, 0 to 2 percent slopes, is an

undifferentiated group in this survey area.

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. Riverwash 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.

Soil Descriptions

1-Andic Cryochrepts, 60 to 90 percent slopes.

These moderately deep to very deep, well drained soils are

on high mountains and ridges. They formed in a mixture of

volcanic ash, glacial till, and colluvium derived from

sandstone and metasedimentary rocks. The native

vegetation is mainly conifers and shrubs. 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 period is about 105

days.

No single profile is representative of these soils. In
one of the more commonly observed ones, however, the

surface is covered with a mat of leaves and twigs about 7

inches thick. Typically, the surface layer is grayish brown

very gravelly loam 7 inches thick. The subsoil is olive brown

very gravelly loam 23 inches thick. The substratum to a

depth of 60 inches is light olive brown very gravelly loam.

The texture, the content of rock fragments, and the depth to

dense glacial till or bedrock vary widely within short

distances. In many areas dense glacial till is at a depth of

more than 30 inches. The depth to bedrock is more than 40

inches. The content of hard rock fragments in the control

section ranges from 15 to 60 percent by weighted average.

The content of weathered rock fragments ranges from 10 to

60 percent by weighted average. The part of the profile

having properties associated with weathered volcanic ash is

10 to more than 60 inches thick.

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

Oakes, and Springsteen soils, soils that are less than 40

inches deep over bedrock, Rock outcrop, slumps, and stony

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

acreage.

Permeability is moderate or moderately rapid in the

Andic Cryochrepts. Available water capacity is moderate

or high. The effective rooting depth is more than 30

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

is severe.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir and western redcedar. The common

understory plants are tall blue huckleberry, bunchberry

dogwood, salal, red huckleberry, Oregongrape, and

longtube twinflower.

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

index for western hemlock is 125. On the basis of a 50-

year site curve, it is 89. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 190

cubic feet per acre per year, occurring at age 50. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, the hazard of erosion, and snowpack. Cable yarding

systems generally are used on this unit. When timber is

harvested, the slope restricts the use of wheeled and

tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

During an average year, the snowpack limits the use of

equipment and restricts access from December through

April. Unsurfaced roads are slippery and soft when wet and

are subject to deep rutting during rainy periods. Rock for

road construction is generally not readily available. Cut and

fill slopes tend

to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. The

areas underlain by dense glacial till are most prone to

landslides. Soil creep is common on this unit. Locating

roads on midslopes requires extensive cutting and filling,

which remove land from production.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established. Carefully

laying out roads and cable yarding paths, properly timing

their use, and using cable systems that lift logs entirely off

the ground reduce the hazard of erosion. A moderate

reduction in productivity can be expected to result from

unmanaged fires in undisturbed areas.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low content of

moisture in the surface layer during the growing season

hinders the survival of planted and naturally established

seedlings. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of the seedlings

and delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. Because of the slope, planting by hand is

difficult. If seed trees are available, natural reforestation of

cutover areas by western hemlock occurs readily. Because

the rooting depth is restricted by the dense glacial till and

bedrock within a depth of 40 inches in some areas, trees

are occasionally subject to windthrow when the soils are wet

and winds are strong.

This map unit is in capability subclass VIle.

2-Andic Cryochrepts-Rock outcrop complex, 60 to 90

percent slopes. This map unit is on high mountains and

ridges. The native vegetation is mainly conifers and shrubs.

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

precipitation is about 80 inches, the average annual air

temperature is about 43 degrees F, and the average frostfree period is about 105 days.

This unit is 70 percent Andic Cryochrepts and 20

percent Rock outcrop. The components of this unit occur as

areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

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

Oakes, and Springsteen soils and soils that are less than

40 inches deep over bedrock. Also included are small

areas of slumps, stony areas, and areas where slopes are

40 to 60 percent. Included areas make up about 10

percent of the total acreage.

The Andic Cryochrepts are moderately deep to very
deep and are well drained. They formed in a mixture of

volcanic ash, glacial till, and colluvium derived from

sandstone and metasedimentary rocks. No single profile is

representative of these soils. In one of the more commonly

observed ones, however, the surface is covered with a mat

of leaves and twigs about 7 inches thick. Typically, the

surface layer is grayish brown very gravelly loam 7 inches

thick. The subsoil is olive brown very gravelly loam 23

inches thick. The substratum to a depth of 60 inches is light

olive brown very gravelly loam. The texture, the content of

rock fragments, and the depth to dense glacial till or bedrock

vary widely within short distances. In many areas dense

glacial till is at a depth of more than 30 inches. The depth to

bedrock is more than 40 inches. The content of hard rock

fragments in the particle-size control section ranges from 15

to 60 percent by weighted average. The content of

weathered rock fragments ranges from 10 to 60 percent by

weighted average. The part of the profile having properties

associated with weathered volcanic ash is 10 to more than

60 inches thick.

Permeability is moderate or moderately rapid in the

Andic Cryochrepts. Available water capacity is moderate

or high. The effective rooting depth is more than 30

inches. Runoff is medium, and the hazard of water

erosion is severe.

Typically, the Rock outcrop is sandstone or

metasedimentary rock. It is hard and generally

unweathered. It occurs as steep cliffs and irregular

formations.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir and western redcedar. The common

understory plants are tall blue huckleberry, bunchberry

dogwood, salal, red huckleberry, Oregongrape, and

longtube twinflower.

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

index for western hemlock is 125. On the basis of a 50-

year site curve, it is 89. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 190

cubic feet per acre per year, occurring at age 50. Yields

are reduced by the extent of the Rock outcrop. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, the hazard of erosion, snowpack, and the Rock

outcrop. The trees can break if they are felled on the Rock

outcrop. The pattern of the Rock outcrop on the landscape

results in a discontinuous slope, which hinders the use of

cable yarding systems. These systems generally are used

on this unit. When timber is harvested, the slope restricts

the use of wheeled and tracked skidding equipment. Cable

yarding systems

generally are safer and disturb the surface less extensively.

During an average year, the snowpack limits the use of

equipment and restricts access from December through

April. Unsurfaced roads are slippery and soft when wet and

are subject to deep rutting during rainy periods. Rock for

road construction is generally not readily available. Cut and

fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. The areas underlain by dense glacial till are most

prone to landslides. Soil creep is common on this unit.

Locating roads on midslopes requires extensive cutting and

filling, which remove land from production.

Because of the Rock outcrop, yarding and skidding

paths converge. This convergence results in compaction of

the underlying soil. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established. Carefully laying out roads and cable

yarding paths, properly timing their use, and using cable

systems that lift logs entirely off the ground reduce the

hazard of erosion. A moderate reduction in productivity

can be expected to result from unmanaged fires in

undisturbed areas.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low content of

moisture in the surface layer during the growing season

hinders the survival of planted and naturally established

seedlings. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of the seedlings

and delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. Because of the slope, planting by hand is

difficult. If seed trees are available, natural reforestation of

cutover areas by western hemlock occurs readily. The Rock

outcrop prevents the even distribution of reforestation.

Because the rooting depth is restricted by the dense glacial

till and bedrock in some areas, trees are occasionally

subject to windthrow when the soils are wet and winds are

strong.

The Andic Cryochrepts are in capability subclass

VIle. The Rock outcrop is in capability subclass VIIIs.

3-Andic Xerochrepts, 60 to 90 percent slopes. These

moderately deep to very deep, well drained soils are on

mountainsides, canyonsides, and ridges. They formed in

volcanic ash, colluvium derived from glacial till, sandstone,

and metasedimentary rocks. The native vegetation is mainly

conifers and shrubs. Elevation is 20 to 1,500 feet. The

average annual precipitation is about 50 inches, the

average annual air temperature is
about 46 degrees F, and the average frost-free period is

about 130 days.

No single profile is representative of these soils. In one

of the more commonly observed ones, however, the

surface is covered with a mat of leaves and twigs about 3

inches thick. Typically, the surface layer is very dark

grayish brown loam 3 inches thick. The subsoil is dark

yellowish brown loam 19 inches thick. The substratum is

dark yellowish brown loam 5 inches thick. Sandstone is at a

depth of about 27 inches. The content of weathered rock

fragments ranges from 35 to 60 percent throughout this

profile. The texture, the content of rock fragments, and the

depth to sandstone, metasedimentary rock, or dense glacial

till vary widely within short distances. If present, dense

glacial till is at a depth of more than 40 inches and bedrock

is at a depth of 20 to 60 inches. The content of hard rock

fragments in the particle-size control section ranges from 15

to 60 percent by weighted average. The content of

weathered rock fragments ranges from 10 to 60 percent by

weighted average. The part of the profile having properties

associated with weathered volcanic ash is 10 to more than

60 inches thick.

Included in this unit are small areas of Pickett, Nati,

Revel, Chuckanut, Blethen, Montborne, Vanzandt, and

Oakes soils, soils that are less than 20 inches deep over

bedrock, Rock outcrop, slumps, stony areas, and areas of

Andic Xerochrepts that have slopes of 40 to 60 percent.

Included areas make up about 15 percent of the total

acreage.

Permeability is moderate or moderately rapid in the

Andic Xerochrepts. Available water capacity is moderate

or high. The effective rooting depth is more than 20

inches. Runoff is medium, and the hazard of water

erosion is severe.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, and western redcedar. The

common understory plants are salal, red huckleberry,

Oregongrape, western swordfern, and vine maple.

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

index for Douglas fir is 140. On the basis of a 50-year site

curve, it is 107. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 145 cubic

feet per acre per year, occurring at age 65. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, the hazard of erosion, and occasional snowpack.

Cable yarding systems generally are used on this unit.

When timber is harvested, the slope restricts the use of

wheeled and tracked skidding equipment. Cable yarding

systems generally are safer and disturb the surface less

extensively. During an

average year, the snowpack limits the use of equipment

and restricts access in January and February. Unsurfaced

roads are slippery and soft when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is generally not readily available. Cut and fill

slopes tend to slump when wet. Following road construction

and clearcutting, road failures and landslides are likely. The

areas underlain by dense glacial till are most prone to

landslides. Soil creep is common on this unit. Locating

roads on midslopes requires extensive cutting and filling,

which remove land from production.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established. A

moderate reduction in productivity can be expected to result

from unmanaged fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting Douglas fir, red alder, or western hemlock

seedlings. Because of the slope, planting seedlings by

hand is difficult. If seed trees are available, natural

reforestation of cutover areas by red alder and western

hemlock occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings. Because

the rooting depth is restricted by the dense glacial till and

bedrock in some areas, trees are occasionally subject to

windthrow when the soils are wet and winds are strong.

This map unit is in capability subclass VIle.

4-Andic Xerochrepts-Rock outcrop complex, 60 to 90

percent slopes. This map unit is on mountainsides,

canyonsides, and ridges. The native vegetation is mainly

conifers and shrubs. Elevation is 20 to 1,200 feet. The

average annual precipitation is about 45 inches, the average

annual air temperature is about 47 degrees F, and the

average frost-free period is about 140 days.

This unit is 75 percent Andic Xerochrepts and 15

percent Rock outcrop. The components of this unit occur

as areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Pickett, Nati,

Chuckanut, Blethen, and Vanzandt soils. Also included are

small areas of slumps, soils that have serpentinitic

mineralogy, stony areas, soils that are less than 20 inches

deep over bedrock or dense glacial till, and areas of Andic

Xerochrepts that have slopes of 40 to 60
percent. Included areas make up about 10 percent of the

total acreage.

The Andic Xerochrepts are moderately deep to very

deep and are well drained. They formed in volcanic ash,

colluvium derived from glacial till, sandstone, and

metasedimentary rocks. No single profile is representative

of these soils. In one of the more commonly observed

ones, however, the surface is covered with a mat of leaves

and twigs about 2 inches thick. Typically, the surface layer

is dark brown loam 6 inches thick. The subsoil is dark

brown loam 11 inches thick. The substratum is dark

yellowish brown sandy loam 12 inches thick. Sandstone is

at a depth of about 29 inches. The content of weathered

rock fragments ranges from 35 to 60 percent throughout

this profile. The texture, the content of rock fragments, and

the depth to bedrock or dense glacial till vary widely within

short distances. If present, the dense glacial till is at a

depth of more than 40 inches. The content of hard rock

fragments in the particle-size control section ranges from

15 to 60 percent by weighted average. The content of

weathered rock fragments ranges from 10 to 60 percent by

weighted average. The part of the profile having properties

associated with weathered volcanic ash is 10 to more than

60 inches thick.

Permeability is moderate or moderately rapid in the

Andic Xerochrepts. Available water capacity is moderate

or high. The effective rooting depth is more than 20

inches. Runoff is medium, and the hazard of water

erosion is severe.

Typically, the Rock outcrop is sandstone or

metasedimentary rock. It is hard and generally

unweathered. It occurs as steep cliffs and irregular

formations.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, and western redcedar. The

common understory plants are salal, red huckleberry,

Oregongrape, western swordfern, and vine maple.

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

index for Douglas fir is 140. On basis of a 50-year site

curve, it is 107. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 145 cubic

feet per acre per year, occurring at age 65. Yields are

reduced by the extent of the Rock outcrop. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, the hazard of erosion, and the Rock outcrop. The

trees can break if they are felled on the Rock outcrop. The

pattern of the Rock outcrop on the landscape results in a

discontinuous slope, which hinders the use of cable yarding

systems. These systems generally are used on this unit.

When timber is

harvested, the slope restricts the use of wheeled and

tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

During an average year, snowpack limits the use of

equipment and restricts access in January and February.

Unsurfaced roads are slippery and soft when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is generally not readily available. Cut and fill

slopes tend to slump when wet. Following road construction

and clearcutting, road failures and landslides are likely. Soil

creep is common on this unit. Locating roads on midslopes

requires extensive cutting and filling, which remove land

from production.

Because of the Rock outcrop, yarding and skidding

paths converge. This convergence results in compaction of

the underlying soil. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established. A moderate reduction in productivity

can be expected to result from unmanaged fires in

undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting Douglas fir, red alder, or western hemlock

seedlings. Because of the slope, planting by hand is difficult.

If seed trees are available, natural reforestation of cutover

areas by western hemlock and red alder occurs readily. The

Rock outcrop prevents the even distribution of reforestation.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Because the rooting depth is

restricted by the bedrock and dense glacial till in some

places, trees are occasionally subject to windthrow when the

soils are wet and winds are strong.

The Andic Xerochrepts are in capability subclass VIle. The

Rock outcrop is in capability subclass VIlls.

5-Andic Xerochrepts, cool-Rock outcrop complex, 60

to 90 percent slopes. This map unit is on mountainsides,

canyonsides, and ridges. The native vegetation is mainly

conifers and shrubs. Elevation is 1,000 to 2,300 feet. The

average annual precipitation is about 65 inches, the average

annual air temperature is about 44 degrees F, and the

average frost-free period is about 120 days.

This unit is 75 percent Andic Xerochrepts and 15

percent Rock outcrop. The components of this unit occur

as areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.
Included in this unit are small areas of Revel,

Montborne, Oakes, Sorensen, and Rinker soils, soils

that are less than 20 inches deep over bedrock or dense

glacial till, soils that have serpentinitic mineralogy,

slumps, stony areas, and areas of Andic Xerochrepts

that have slopes of 40 to 60 percent. Included areas

make up about 10 percent of the total acreage.

The Andic Xerochrepts are moderately deep to very

deep and are well drained. They formed in volcanic ash,

colluvium derived from glacial till, sandstone, and

metasedimentary rocks. No single profile is representative

of these soils. In one of the more commonly observed ones,

however, the surface is covered with a mat of leaves and

twigs about 3 inches thick. Typically, the surface layer is

dark brown loam 7 inches thick. The subsoil is yellowish

brown loam 24 inches thick. The substratum to a depth of

60 inches is yellowish brown loam. The content of

weathered rock fragments ranges from 35 to 60 percent

throughout this profile, and the depth to bedrock or dense

glacial till varies widely within short distances. In many

areas dense glacial till is at a depth of more than 40 inches.

If present, bedrock is at a depth of more than 20 inches.

The content of hard rock fragments in the particle-size

control section ranges from 15 to 60 percent by weighted

average. The content of weathered rock fragments ranges

from 10 to 60 percent by weighted average. The part of the

profile having properties associated with volcanic ash is 10

to more than 60 inches thick.

Permeability is moderate or moderately rapid in the

Andic Xerochrepts. Available water capacity is moderate

or high. The effective rooting depth is more than 20

inches. Runoff is medium, and the hazard of water

erosion is severe.

Typically, the Rock outcrop is sandstone or

metasedimentary rock. It is hard and generally

unweathered. It occurs as steep cliffs and irregular

formations.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent is western redcedar. The common

understory plants are salal, red huckleberry, Oregongrape,

western swordfern, and vine maple.

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

index is 134 for western hemlock and 117 for Douglas fir.

On the basis of a 50-year site curve, it is 96 for western

hemlock and 85 for Douglas fir. The highest average

growth rate in unmanaged, even-aged stands of western

hemlock is 207 cubic feet per acre per year, occurring at

age 50. For Douglas fir, it is 110 cubic feet per acre per

year, occurring at age 60. Yields are reduced by the extent

of the Rock outcrop. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, the hazard of erosion, occasional snowpack, and the

Rock outcrop. The trees can break if they are felled on the

Rock outcrop. The pattern of the Rock outcrop on the

landscape results in a discontinuous slope, which hinders

the use of cable yarding systems. These systems generally

are used on this unit. When timber is harvested, the slope

restricts the use of wheeled and tracked skidding equipment.

Cable yarding systems generally are safer and disturb the

surface less extensively. During an average year, the

snowpack limits the use of equipment and restricts access

from December through March. Unsurfaced roads are

slippery and soft when wet and are subject to deep rutting

during rainy periods. Rock for road construction is generally

not readily available. Cut and fill slopes tend to slump when

wet. Following road construction and clearcutting, road

failures and landslides are likely. The areas underlain by

dense glacial till are most prone to landslides. Soil creep is

common on this unit. Locating roads on midslopes requires

extensive cutting and filling, which remove land from

production.

Because of the Rock outcrop, yarding and skidding

paths converge. This convergence results in compaction of

the underlying soil. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established. A moderate reduction in productivity

can be expected to result from unmanaged fires in

undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting Douglas fir or western hemlock seedlings.

Because of the slope, planting by hand is difficult. If seed

trees are available, natural reforestation of cutover areas by

western hemlock occurs readily. The Rock outcrop prevents

the even distribution of reforestation. When openings are

made in the canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Because the rooting depth is restricted by the

bedrock and dense glacial till in some areas, trees are

occasionally subject to windthrow when the soils are wet

and winds are strong.

The Andic Xerochrepts are in capability subclass

VIle. The Rock outcrop is in capability subclass VIIIs.

6-Barneston gravelly loam, 0 to 8 percent slopes.

This very deep, somewhat excessively drained soil is on

outwash terraces. It formed in an admixture of loess
and volcanic ash over glacial outwash. The native

vegetation is mainly conifers and shrubs. Elevation is 300 to

1,000 feet. The average annual precipitation is about 60

inches, the average annual air temperature is about 49

degrees F, and the average frost-free period is about 160

days.

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

leaves, and twigs 2.5 inches thick. When mixed to a depth

of 8 inches, the surface layer is dark brown gravelly loam.

The subsoil is dark brown very gravelly loam 6 inches thick.

The upper 26 inches of the substratum is dark yellowish

brown and olive brown extremely gravelly sand. The lower

part to a depth of 60 inches is dark grayish brown extremely

gravelly sand. The depth to extremely gravelly sand ranges

from 13 to 24 inches. In some areas the surface layer is

very gravelly loam, very gravelly sandy loam, or cobbly

loam. In other areas the soil has less than 35 percent rock

fragments in the subsoil, has a substratum of extremely

gravelly sand at a depth of 24 to 36 inches, or has a

substratum of very gravelly sandy loam.

Included in this unit are small areas of Sehome and

Blethen soils, poorly drained soils in depressions, and

Barneston soils that have slopes of more than 8 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is moderately rapid in the upper part of the

Barneston soil and very rapid in the substratum. Available

water capacity is low. The effective rooting depth is 60

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

slight.

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

hay and pasture, as a source of aggregate, and as a site for

homes.

The main limitation in the areas used for hay and

pasture is the low available water capacity. Proper

stocking rates, pasture rotation, and restricted grazing

during short wet periods help to keep the pasture in good

condition, minimize compaction, and reduce the runoff

rate. In summer, irrigation is required for maximum

production. Erosion is a hazard during periods of

reestablishment.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, red alder, and bigleaf maple. The common

understory plants are Oregongrape, salal, western

swordfern, western brackenfern, red huckleberry, and vine

maple.

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

index for Douglas fir is 150. On the basis of a 50-year site

curve, it is 118. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 158 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced

roads are soft when wet and are subject to rutting during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rounded pebbles and cobbles for road

construction are readily available.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a moderate

degree of soil displacement when the soil is dry. Carefully

laying out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the degree

of compaction and displacement. A moderate reduction in

productivity can be expected to result from unmanaged fires

in undisturbed areas.

Seedling mortality and establishment are the main

concerns affecting timber production. Reforestation can be

accomplished by planting Douglas fir seedlings. A high soil

temperature and a low content of moisture in the soil during

the growing season cause a high rate of seedling mortality.

If seed trees are available, natural reforestation of cutover

areas by Douglas fir, red alder, and western hemlock occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

delay the establishment of seedlings. Competing vegetation

can be controlled by mechanical or chemical means.

This unit is well suited to homesite development. In

shallow excavations special retainer walls may be needed

to keep cutbanks from caving. The main limitation on sites

for septic tank absorption fields is a poor filtering capacity

in the substratum.

This map unit is in capability subclass Ille.

7-Barneston very gravelly loam, 8 to 15 percent

slopes. This very deep, somewhat excessively drained soil is

on outwash terraces and on slopes between the terraces. It

formed in an admixture of loess and volcanic ash over glacial

outwash. The native vegetation is mainly conifers and shrubs.

Elevation is 400 to 1,000 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 3 inches thick. The surface layer is dark

brown very gravelly loam 4 inches thick. The upper 7 inches

of the subsoil is dark brown very gravelly loam. The lower 8

inches is strong brown very gravelly loam. The substratum to

a depth of 60 inches is dark grayish brown extremely gravelly

sand. The depth to extremely gravelly sand ranges from 13

to 24 inches. In some areas the surface layer is gravelly

loam, very gravelly sandy loam, or cobbly loam. In other

areas the soil has less than 35 percent rock fragments
in the subsoil, has a substratum of extremely gravelly sand

at a depth of 24 to 36 inches, or has a substratum of very

gravelly sandy loam.

Included in this unit are small areas of Sehome and

Blethen soils and small areas of Barneston soils that have

slopes of more than 15 percent or less than 8 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is moderately rapid in the upper part of the

Barneston soil and very rapid in the substratum. Available

water capacity is low.; The effective rooting depth is 60

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

slight.

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

a source of aggregate and as a site for homes.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, red alder, and bigleaf maple. The common

understory plants are Oregongrape, western swordfern,

western brackenfern, red huckleberry, and vine maple.

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

index for Douglas fir is 150. On the basis of a 50-year site

curve, it is 118. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 158 cubic

feet per acre per year, occurring at age 60.

The kind of equipment that can be used and the time of

the year when it can be used. normally are not restricted on

this unit. Logging roads require suitable surfacing for yearround use. Rounded pebbles and cobbles for road

construction are readily available. A moderate reduction in

productivity can be expected to result from unmanaged fires

in undisturbed areas.

Seedling mortality and establishment are the main

concerns affecting timber production. Reforestation can be

accomplished by planting Douglas fir seedlings. A high soil

temperature and a low content of moisture in the soil

during the growing season cause a high rate of seedling

mortality. If seed trees are available, natural reforestation

of cutover areas by Douglas fir, red alder, and western

hemlock occurs periodically. When openings are made in

the canopy, the uncontrolled invasion and growth of

competing plants can delay the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

If this unit is used for homesite development, the main

limitation is the slope. The main limitation on sites for septic

tank absorption fields is a poor filtering capacity in the

substratum. During the rainy season, the effluent from

onsite sewage disposal systems can seep at points

downslope. The slope affects the installation of septic tank

absorption fields. The absorption lines should be installed

on the contour.

This map unit is in capability subclass IVe.

8-Barneston very gravelly loam, 15 to 30 percent

slopes. This very deep, somewhat excessively drained soil

is on outwash terraces and on slopes between the terraces.

It formed in an admixture of loess and volcanic ash over

glacial outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 400 to 1,200 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

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

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

brown very gravelly loam 4 inches thick. The upper 5

inches of the subsoil is strong brown extremely gravelly

sandy loam. The lower 6 inches is strong brown very

gravelly sandy loam. The substratum to a depth of 60

inches is brownish yellow and light yellowish brown very

gravelly sand. The depth to very gravelly sand ranges from

13 to 24 inches. In some areas the surface layer is gravelly

loam, very gravelly sandy loam, or cobbly loam. In other

areas the soil has less than 35 percent rock fragments in

the subsoil, has a substratum of very gravelly sand at a

depth of 24 to 36 inches, or has a substratum of very

gravelly sandy loam.

Included in this unit are small areas of Sehome and

Blethen soils and small areas of Barneston soils that have

slopes of more than 30 percent or less than 15 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is moderately rapid in the upper part of the

Barneston soil and very rapid in the substratum. Available

water capacity is low or moderate. The effective rooting

depth is 60 inches. Runoff is slow, and the hazard of water

erosion is slight.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, red alder, and bigleaf maple. The common

understory plants are Oregongrape, salal, western

swordfern, western brackenfern, red huckleberry, and vine

maple.

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

index for Douglas fir is 150. On the basis of a 50-year site

curve, it is 118. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 158 cubic

feet per acre per year, occurring at age 60.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted on

this unit. Logging roads require suitable surfacing for yearround use. Rounded pebbles and cobbles for road

construction are readily available. Cut and fill slopes tend

to ravel when dry.

Steep skid trails and firebreaks are subject to rilling

and gullying unless adequate water bars are provided
or a protective plant cover is established. A moderate

reduction in productivity can be expected to result from

unmanaged fires in undisturbed areas.

Seedling mortality and establishment are the main

concerns affecting timber production. Reforestation can be

accomplished by planting Douglas fir seedlings. A high soil

temperature and a low content of moisture in the soil

during the growing season cause a high rate of seedling

mortality. If seed trees are available, natural reforestation

of cutover areas by Douglas fir, red alder, and western

hemlock occurs periodically. When openings are made in

the canopy, the uncontrolled invasion and growth of

competing plants can delay the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

This map unit is in capability subclass IVe.

9-Barneston very gravelly loam, 30 to 60 percent

slopes. This very deep, somewhat excessively drained soil

is on outwash terraces and terrace escarpments. It formed

in an admixture of loess and volcanic ash over glacial

outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 400 to 1,200 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 6 inches thick. The surface layer is dark

brown very gravelly loam 11 inches thick. The subsoil is

dark yellowish brown extremely gravelly sandy loam 10

inches thick. The upper 16 inches of the substratum is dark

yellowish brown extremely gravelly sand. The lower part to

a depth of 60 inches is dark grayish brown extremely

gravelly sand. The depth to extremely gravelly sand ranges

from 13 to 24 inches. In some areas the surface layer is

gravelly loam, very gravelly sandy loam, or cobbly loam. In

other areas the soil has less than 35 percent rock

fragments in the subsoil, has a substratum of extremely

gravelly sand at a depth of 24 to 36 inches, or has a

substratum of very gravelly sandy loam.

Included in this unit are small areas of Sehome and

Blethen soils and small areas of Barneston soils that

have slopes of more than 60 percent or less than 30

percent. Included areas make up about 10 percent of the

total acreage.

Permeability is moderately rapid in the upper part of the

Barneston soil and very rapid in the substratum. Available

water capacity is low. The effective rooting depth is 60

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

is moderate.

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

a source of aggregate.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, red alder, and bigleaf maple. The common

understory plants are Oregongrape, salal, western

swordfern, western brackenfern, red huckleberry, and

vine maple.

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

index for Douglas fir is 150. On the basis of a 50-year site

curve, it is 118. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 158 cubic

feet per acre per year, occurring at age 60.

The. main limitations affecting timber harvesting are the

slope and the hazard of erosion. Logging roads require

suitable surfacing for year-round use. Rounded pebbles

and cobbles for road construction are readily available. Cut

and fill slopes tend to ravel when dry. Soil creep is

common on this unit.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground reduce the hazard of erosion. A

moderate reduction in productivity can be expected to result

from unmanaged fires in undisturbed areas.

Seedling mortality and establishment are the main

concerns affecting timber production. Reforestation can be

accomplished by planting Douglas fir seedlings. A high soil

temperature and a low content of moisture in the soil

during the growing season cause a high rate of seedling

mortality. If seed trees are available, natural reforestation

of cutover areas by Douglas fir, red alder, and western

hemlock occurs periodically. When openings are made in

the canopy, the uncontrolled invasion: and growth of

competing plants can delay the establishment of seedlings.

Competing, vegetation can be controlled by mechanical or

chemical means.

This map unit is in capability subclass VIle.

10-Barnhardt gravelly loam, 0 to 5 percent slopes.

This very deep, well drained soil is on outwash terraces. It

formed in a mixture of volcanic ash, loess, and glacial

outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

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

leaves, and twigs 1 inch thick. The surface layer is dark

brown gravelly loam 9 inches thick. The subsoil is

yellowish brown extremely gravelly loam 12 inches thick.

The upper 21 inches of the substratum is yellowish brown

extremely gravelly sandy loam. The lower part to a depth

of 60 inches is yellowish brown
extremely gravelly loam. In some areas the surface layer

is loam, gravelly silt loam, or very gravelly loam. In other

areas the soil has 15 to 35 percent rock fragments in the

subsoil or is 30 to 60 inches deep to very gravelly sand.

Included in this unit are small areas of Clipper soils on

the lower parts of the landscape, organic soils in

depressions, Kickerville soils, and Barnhardt soils that have

slopes of 5 to 10 percent. Included areas make up about 5

percent of the total acreage.

Permeability is moderately rapid in the Barnhardt soil.

Available water capacity is moderate. The effective rooting

depth is 60 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used mainly for hay and pasture. It also is

used as woodland, as a source of aggregate, and as a site

for homes.

The main limitations in the areas used for hay and

pasture are the moderate available water capacity and the

gravelly surface layer. In summer, irrigation is required for

maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, and red alder. The common understory plants are

salal, red huckleberry, Oregongrape, western swordfern,

and trailing blackberry.

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

index for Douglas fir is 136. On the basis of a 50-year site

curve, it is 106. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 139 cubic

feet per acre per year, occurring at age 70.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Typically, the

surface layer is loose when dry. As a result, the use of

wheeled and tracked equipment is limited. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

surfacing for year-round use. Rounded pebbles and

cobbles for road construction are readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist, a high

degree of puddling when the soil is wet, and a moderate

degree of soil displacement when the soil is dry. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction, puddling, and displacement. A

moderate reduction in productivity can be expected to

result from unmanaged fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by

western hemlock occurs periodically. A high soil

temperature and a low content of moisture in the soil during

the growing season can cause seedling mortality. When

openings are made in the canopy, the uncontrolled invasion

and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This unit is suited to homesite development. It has

few limitations.

This map unit is in capability subclass Ills.

11-Bellingham silty clay loam, 0 to 2 percent slopes.

This very deep, poorly drained soil is in depressions on

terraces. It formed in an admixture of loess, alluvium, and

glaciolacustrine deposits. The native vegetation is mainly

trees and shrubs. Elevation is 20 to 200 feet. The average

annual precipitation is about 45 inches, the average annual

air temperature is about 50 degrees F, and the average

frost-free period is about 170 days.

Typically, the surface layer is very dark grayish brown

silty clay loam 10 inches thick. The subsoil is very dark

grayish brown, dark brown, and olive brown, mottled silty

clay loam 14 inches thick. The substratum to a depth of 60

inches is grayish brown, mottled silty clay loam. In some

areas the surface layer is silt loam, silty clay, or mucky silt

loam. In other areas the soil has 20 to 35 percent clay or

more than 60 percent clay in the subsoil or substratum,

has a light colored surface layer, or has lenses of sand in

the substratum.

Included in this unit are small areas of Skipopa,

Everson, Whatcom, and Shalcar soils, partially drained

Bellingham soils, and Bellingham soils having a surface

layer that is 5 to 8 inches thick. Included areas make up

about 15 percent of the total acreage.

Permeability is slow in the Bellingham soil. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at or near

the surface from November through April. Runoff usually is

very slow, but the soil may be ponded during the winter.

There is no hazard of erosion.

This unit is used mainly for hay and pasture. It also is

used as cropland and woodland.

The main limitations in the areas used for hay and

pasture are the high water table and the slow permeability.

Proper stocking rates, pasture rotation, and restricted

grazing when the soil is wet help to keep the pasture in

good condition. Grazing when the soil is wet results in

compaction of the surface layer and poor tilth. The

wetness limits the choice of plants and the period of

cutting or grazing and increases the risk of winterkill.

The main limitations in the areas used as cropland
are the high water table and the slow permeability. The

principal crop is corn silage. This unit also is suited to other

climatically adapted crops. Some areas have been partially

drained. Maintaining the drainage system permits fieldwork

to be conducted earlier in the spring and increases yields.

The wetness can be reduced in some areas by diversions,

which intercept water, and by open ditches, which remove

excess water. Returning all crop residue to the soil and

including grasses, legumes, or grass-legume mixtures in

the cropping sequence help to maintain fertility and tilth.

Red alder is the main woodland species. Among the

trees of limited extent are bigleaf maple, western redcedar,

and western hemlock. The common understory plants are

western swordfern, trailing blackberry, western

brackenfern, salmonberry, and Douglas spirea.

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

for red alder is 85. The highest average growth rate in

unmanaged, even-aged stands of red alder is 92 cubic feet

per acre per year, occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the use

of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and may be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is needed to

maintain a stable and uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the

seasonal high water table, trees are frequently subject to

windthrow when the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the high water table and the shrinkswell potential. The wetness can be reduced by building

the house on a pad and by installing drainage tile around

footings if a suitable outlet is available. Properly designing

foundations and footings and diverting runoff away from the

buildings help to prevent the structural damage caused by

shrinking and swelling. The main limitations on sites for

septic tank absorption fields are the seasonal high water

table and the slow permeability. Installing absorption lines

that are longer than normal helps to overcome these

limitations.

This map unit is in capability subclass VIw.

12-Birchbay silt loam, 0 to 3 percent slopes. This

very deep, moderately well drained soil is on wavereworked glaciomarine drift plains. It formed in an

admixture of volcanic ash and loess over glaciofluvial

deposits and glaciomarine drift. The native vegetation is

mainly conifers and shrubs. Elevation is 50 to 350 feet.

The average annual precipitation is about 35 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 180 days.

Typically, the surface layer is dark brown silt loam 8

inches thick. The upper 4 inches of the subsoil is dark

brown silt loam. The lower 12 inches is dark yellowish

brown gravelly silt loam. The upper 18 inches of the

substratum is dark yellowish brown very gravelly sand. The

lower part to a depth of 60 inches is light olive brown

loam. The depth to very gravelly sand ranges from 14 to

32 inches. In some areas the surface layer is loam or

gravelly silt loam. In other areas the soil is very gravelly

sandy loam in the upper part of the substratum, has 15 to

35 percent pebbles in the lower part of the substratum,

does not have very gravelly sand in the upper part of the

substratum, or has less than 35 percent pebbles in the

upper part of the substratum.

Included in this unit are small areas of Whitehorn,

Labounty, Kickerville, Clipper, Hale, and Tromp soils, soils

that are 30 to 40 inches deep to the lower part of the

substratum, soils that are less than 14 inches deep to very

gravelly sand, and Birchbay soils that have slopes of more

than 3 percent. Included areas make up about 20 percent

of the total acreage.

Permeability is moderate in the upper part of the

Birchbay soil, very rapid in the sandy upper part of the

substratum, and slow in the loamy lower part. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a depth

of 2 to 4 feet from December through April. Runoff is very

slow, and there is no hazard of erosion.

This unit is used mainly for hay and pasture. It also is

used as cropland, as woodland, and as a site for homes.

Because of the nearly level slope, this soil remains

saturated for longer periods than other Birchbay soils.
This saturation delays the use of equipment, increases the

hazard of puddling, and shortens the effective growing

season unless the soil is drained. If the unit is used for

hay and pasture, proper stocking rates, pasture rotation,

and restricted grazing during wet periods help to keep the

pasture in good condition. Grazing when the soil is wet

results in compaction of the surface layer and poor tilth.

The main limitation in the areas used as cropland is the

seasonal high water table. The principal crop is corn

silage. This unit also is suited to other climatically adapted

crops. Some areas have been partially drained. Maintaining

the drainage system permits fieldwork to be conducted

earlier in the spring and increases the yields of perennial

crops. The wetness can be reduced in some areas by

diversions, which intercept water, and by open ditches,

which remove excess water.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, grand fir, and paper birch. The common

understory plants are vine maple, red huckleberry, salal,

western swordfern, and Oregongrape.

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

index for Douglas fir is 150. On the basis of a 50-year site

curve, it is 115. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 158 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Small amounts of rounded pebbles for road

construction are readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted

by the seasonal high water table, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is

available. If used as a base for roads and streets, the soil

can be mixed with the underlying sand and gravel, which

can increase the strength and stability of the soil. In

shallow excavations special retainer walls may be needed

to keep cutbanks from caving.

The main limitations on sites for septic tank absorption

fields are the seasonal high water table, the slow

permeability, and a poor filtering capacity. Installing

absorption lines that are longer than normal helps to

overcome these limitations.

This map unit is in capability subclass Ilw.

13-Birchbay silt loam, 3 to 8 percent slopes. This

very deep, moderately well drained soil is on wavereworked glaciomarine drift plains. It formed in an

admixture of volcanic ash and loess over glaciofluvial

deposits and glaciomarine drift. The native vegetation is

mainly conifers and shrubs. Elevation is 50 to 350 feet. The

average annual precipitation is about 35 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 180 days.

Typically, the surface layer is dark brown silt loam 8

inches thick. The upper 4 inches of the subsoil is dark

brown silt loam. The lower 12 inches is dark yellowish

brown gravelly silt loam. The upper 18 inches of the

substratum is dark yellowish brown very gravelly sand. The

lower part to a depth of 60 inches is light olive brown loam.

The depth to very gravelly sand ranges from 14 to 32

inches. In some areas the soil is very gravelly sandy loam

in the upper part of the substratum, has 15 to 35 percent

pebbles in the lower part of the substratum, does not have

very gravelly sand in the upper part of the substratum, or

has less than 35 percent pebbles in the upper part of the

substratum.

Included in this unit are small areas of Whitehorn,

Labounty, Kickerville, Everett, Clipper, Hale, and Tromp

soils, soils that are 30 to 40 inches deep to the lower part

of the substratum, soils that are less than 14 inches deep

to very gravelly sand, and Birchbay soils that have slopes

of more than 8 percent or less than 3 percent. Included

areas make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Birchbay soil, very rapid in the sandy upper part of the

substratum, and slow in the loamy lower part. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 2 to

4 feet from December through April. Runoff is slow, and

the hazard of water erosion is slight.
This unit is used mainly for hay and pasture. It also is

used as cropland, as woodland, and as a site for homes.

This unit is suited to hay and pasture. It has few

limitations. Proper stocking rates, pasture rotation, and

restricted grazing during wet periods help to keep the

pasture in good condition. Grazing when the soil is wet

results in compaction of the surface layer and poor tilth.

The main limitation in the areas used as cropland is the

seasonal high water table. The principal crop is corn silage.

This unit also is suited to other climatically adapted crops.

The wetness can be reduced in some areas by diversions,

which intercept water, and by open ditches, which remove

excess water. In the areas that are drained, the dominant

method of drainage is open ditches.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, grand fir, and paper birch. The common

understory plants are vine maple, red huckleberry, salal,

western swordfern, and Oregongrape.

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

index for Douglas fir is 150. On the basis of a 50-year site

curve, it is 115. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 158 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Small amounts of rounded pebbles for road

construction are readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted

by the seasonal high water table, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable

outlet is available. If used as a base for roads and streets,

the soil can be mixed with the underlying sand and gravel,

which can increase the strength and stability of the soil. In

shallow excavations special retainer walls may be needed

to keep cutbanks from caving.

The main limitations on sites for septic tank absorption

fields are the seasonal high water table, the slow

permeability, and a poor filtering capacity. These limitations

can be overcome by using interceptor drains, by installing

the absorption field at a shallow depth, and by installing

absorption lines that are longer than normal and that are on

the contour.

This map unit is in capability subclass Ile.

14-Birchbay silt loam, 8 to 15 percent slopes. This

very deep, moderately well drained soil is on wavereworked glaciomarine drift plains. It formed in an

admixture of volcanic ash and loess over glaciofluvial

deposits and glaciomarine drift. The native vegetation is

mainly conifers and shrubs. Elevation is 50 to 350 feet. The

average annual precipitation is about 35 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 180 days.

Typically, the surface layer is dark brown silt loam 8

inches thick. The upper 4 inches of the subsoil is dark

brown silt loam. The lower 12 inches is dark yellowish

brown gravelly silt loam. The upper 18 inches of the

substratum is dark yellowish brown very gravelly sand. The

lower part to a depth of 60 inches is light olive brown loam.

The depth to very gravelly sand ranges from 14 to 32

inches. In some areas the surface layer is loam or gravelly

silt loam. In other areas the soil is very gravelly sandy loam

in the upper part of the substratum, has 15 to 35 percent

pebbles in the lower part of the substratum, does not have

very gravelly sand in the upper part of the substratum, or

has less than 35 percent pebbles in the upper part of the

substratum.

Included in this unit are small areas of Whitehorn,

Kickerville, Everett, and Clipper soils, soils that are 30 to

40 inches deep to the lower part of the substratum, seep

areas, soils that are less than 14 inches deep to very

gravelly sand, and Birchbay soils that have slopes of more

than 15 percent or less than 8 percent. Included areas

make up about 15 percent, of the total acreage.

Permeability is moderate in the upper part of the

Birchbay soil, very rapid in the sandy upper part of the

substratum, and slow in the loamy lower part. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a depth

of 2 to 4 feet from December through April. Runoff is slow,

and the hazard of water erosion is slight.
This unit is used mainly as woodland. It also is used for

hay and pasture.

The main limitation in the areas used for hay and

pasture is the hazard of erosion during periods of

reestablishment. Proper stocking rates, pasture rotation,

and restricted grazing during short wet periods help to keep

the pasture in good condition. Grazing when the soil is wet

results in compaction of the surface layer and poor tilth.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, grand fir, and paper birch. The common

understory plants are vine maple, red huckleberry, salal,

western swordfern, and Oregongrape.

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

index for Douglas fir is 150. On the basis of a 50-year site

curve, it is 115. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 158 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Small amounts of rounded pebbles for road

construction are readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the seasonal high water table, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

If this unit is used for homesite development, the main

limitation is the seasonal high water table. In shallow

excavations special retainer walls may be needed to keep

cutbanks from caving. The main limitations on sites for

septic tank absorption fields are the seasonal high water

table, the slow permeability, and a poor filtering capacity.

Effluent from absorption fields can surface in downslope

areas and create a hazard to health.

This map unit is in capability subclass Ille.

15-Blainegate silty clay, 0 to 1 percent slopes. This

very deep, poorly drained soil is on marine terraces. It

formed in marine deposits. The native vegetation is mainly

trees and shrubs. Elevation is 10 to 100 feet. The average

annual precipitation is about 35 inches, the average annual

air temperature is about 50 degrees F, and the average

frost-free period is about 180 days.

Typically, the surface layer is very dark grayish brown,

mottled silty clay 9 inches thick. The subsoil is dark gray,

mottled clay 18 inches thick. The upper 18 inches of the

substratum is gray, mottled clay. The lower part to a depth

of 60 inches is light brownish gray, mottled clay. In some

areas the surface layer is silty clay loam. In other areas the

substratum contains lenses of loamy or sandy material or

is 35 to 60 percent clay.

Included in this unit are small areas of Skipopa,

Whatcom, Whitehorn, Shalcar, and Yelm soils and drained

Blainegate soils. Included areas make up about 15 percent

of the total acreage.

Permeability is very slow in the Blainegate soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at or near the

surface from November through June. Runoff usually is

very slow, but the soil may be ponded during the winter.

There is no hazard of erosion.

This unit is used mainly for hay and pasture. It also is

used as cropland and woodland.

The main limitations in the areas used for hay and

pasture are the seasonal high water table and the very

slow permeability. Proper stocking rates, pasture rotation,

and restricted grazing during wet periods help to keep the

pasture in good condition. Grazing when the soil is wet

results in compaction of the surface layer and poor tilth.

The water table limits the use of this unit to grasses unless

a drainage system is installed. The wetness limits the

choice of plants and the period of cutting or grazing and

increases the risk of winterkill.

The main limitations in the areas used as cropland are

the seasonal high water table and the very slow

permeability. The principal crop is corn silage. This unit

also is suited to other climatically adapted crops. Tile drains

and field ditches are needed to lower the high water table if

deep-rooted plants are to be grown. Some areas have

been partially drained. Maintaining the drainage system

permits fieldwork to be conducted earlier in the spring and

increases yields. Drainage tiles should be closely spaced

because of the very slow permeability. Tile drains and open

drains can be used to lower the water table if a suitable

outlet is available. The wetness can be reduced in some

areas by diversions, which intercept water, and by open

ditches,
which remove excess water. Returning all crop residue to

the soil and including grasses, legumes, or grass-legume

mixtures in the cropping sequence help to maintain fertility

and tilth.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar and western

hemlock. The common understory plants are western

swordfern, western brackenfern, trailing blackberry,

salmonberry, and Douglas spirea.

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

index for red alder is estimated to be 85. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 92 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the

use of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads may be impassable

during rainy periods. Extra rock is needed to maintain a

stable and uniform road surface.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The seasonal high water table hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the

seasonal high water table, trees are frequently subject to

windthrow when the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the seasonal high water table and the

shrink-swell potential. The wetness can be reduced by

building the house on a pad and by installing drainage tile

around footings if a suitable outlet is available. Properly

designing foundations and footings and diverting runoff

away from the buildings help to prevent the structural

damage caused by shrinking and swelling. The main

limitations on sites for septic tank absorption fields are the

seasonal high water table and

the very slow permeability. Installing absorption lines

that are longer than normal helps to overcome these

limitations.

This map unit is in capability subclass VIw.

16-Blainegate-Urban land complex, 0 to 1 percent

slopes. This map unit is on marine terraces. The native

vegetation is mainly trees and shrubs. Elevation is 10 to 100

feet. The average annual precipitation is about 35 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free period is about 180 days.

This unit is 50 percent Blainegate silty clay loam and

30 percent Urban land. The components of this unit occur

as areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Skipopa,

Whatcom, Whitehorn, and Yelm soils. Included areas

make up about 20 percent of the total acreage.

The Blainegate soil is very deep and poorly drained. It

formed in marine deposits. Typically, the surface layer is

very dark grayish brown, mottled silty clay 9 inches thick.

The subsoil is dark gray, mottled clay 18 inches thick. The

upper 18 inches of the substratum is gray, mottled clay. The

lower part to a depth of 60 inches is light brownish gray,

mottled clay. In some areas the surface layer is silty clay. In

other areas the substratum has lenses of loamy or sandy

material or has 35 to 60 percent clay.

Permeability is very slow in the Blainegate soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at or near the

surface from November through June. Runoff usually is very

slow, but the soil may be ponded during the winter. There is

no hazard of erosion.

The Urban land consists of areas covered by streets,

buildings, parking lots, and other structures that so obscure

the soils that identification of the soil series is not feasible.

The Blainegate soil is used for lawns, gardens, or

parks.

If this unit is used for homesite development, the main

limitations are the seasonal high water table and the

shrink-swell potential. The wetness can be reduced by

building the house on a pad and by installing drainage tile

around footings if a suitable outlet is available. Properly

designing foundations and footings and diverting runoff

away from the buildings help to prevent the structural

damage caused by shrinking and swelling. The main

limitations on sites for septic tank absorption fields are the

seasonal high water table and the very slow permeability.

Installing absorption lines
that are longer than normal helps to overcome these

limitations.

The Blainegate soil is in capability subclass VIw. The

Urban land is in capability subclass VIlls.

17-Blethen gravelly loam, 5 to 15 percent slopes.

This very deep, well drained soil is on side slopes and toe

slopes of foothills. It formed in colluvium, glacial till, and

slope alluvium with an admixture of volcanic ash and loess.

The native vegetation is mainly conifers and shrubs.

Elevation is 500 to 1,400 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 4 inches thick. When mixed to a depth of

6 inches, the surface layer is dark brown gravelly loam.

The upper 8 inches of the subsoil is dark brown gravelly

loam. The lower 6 inches is yellowish brown very gravelly

loam. The substratum to a depth of 60 inches is brown and

yellowish brown very gravelly loam. In some areas the

surface layer is very gravelly loam, gravelly silt loam, or

very gravelly silt loam. In other areas the soil has less than

35 percent rock fragments in the subsoil and substratum or

is 40 to 60 inches deep to dense glacial till or bedrock.

Included in this unit are small areas of Barneston,

Chuckanut, Heisler, Nati, Sehome, and Vanzandt soils,

slump areas, stony areas, and Blethen soils that have

slopes of more than 15 percent or less than 5 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is moderate in the Blethen soil. Available

water capacity is high. The effective rooting depth is 60

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

is slight.

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

for hay and pasture and as a site for homes.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, and bigleaf maple. The common

understory plants are salal, Oregongrape, vine maple, red

huckleberry, western swordfern, longtube twinflower, and

trailing blackberry.

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

index for Douglas fir is 149. On the basis of a 50-year site

curve, it is 115. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 157 cubic

feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Rock for road construction is not

readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling. A

moderate reduction in productivity can be expected to

result from unmanaged fires in undisturbed areas.

Seedling establishment and mortality are the main

concerns affecting timber production. The seedling

mortality rate is higher on ridgetops that are subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. A high soil temperature and a low

moisture content in the soil during the growing season can

cause seedling mortality. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily and reforestation by western hemlock and Douglas

fir occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

The main limitation in the areas used for hay and

pasture is the hazard of erosion during periods of

reestablishment. Proper stocking rates, pasture rotation,

and restricted grazing during short wet periods help to keep

the pasture in good condition and help to control runoff

during periods of reestablishment.

The main limitation affecting homesite development is

the slope. During the rainy season, the effluent from

onsite sewage disposal systems can seep at points

downslope. The slope affects the installation of septic

tank absorption fields. The absorption lines should be

installed on the contour.

This map unit is in capability subclass Ille.

18-Blethen gravelly loam, 15 to 30 percent slopes.

This very deep, well drained soil is on side slopes and toe

slopes of foothills. It formed in colluvium, glacial till, and

slope alluvium with an admixture of volcanic ash and

loess. The native vegetation is mainly conifers and shrubs.

Elevation is 500 to 1,400 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

Typically, the surface is covered with a mat of
needles, leaves, and twigs 1 inch thick. When mixed to a

depth of 6 inches, the surface layer is dark brown gravelly

loam. The upper 12 inches of the subsoil is dark brown

very cobbly loam. The lower 23 inches is dark yellowish

brown very cobbly loam. The substratum to a depth of 60

inches is olive brown very cobbly loam. In some areas the

surface layer is very gravelly loam, gravelly silt loam, or

very gravelly silt loam. In other areas the soil has less than

35 percent rock fragments in the subsoil and substratum or

is 40 to 60 inches deep to dense glacial till or bedrock.

Included in this unit are small areas of Barneston,

Chuckanut, Heisler, Nati, Sehome, and Vanzandt soils,

soils that have serpentinitic mineralogy, slump areas, stony

areas, and Blethen soils that have slopes of more than 30

percent or less than 15 percent. Included areas make up

about 10 percent of the total acreage.

Permeability is moderate in the Blethen soil. Available

water capacity is high. The effective rooting depth is 60

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

slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are salal,

Oregongrape, vine maple, red huckleberry, western

swordfern, longtube twinflower, and trailing blackberry.

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

index for Douglas fir is 149. On the basis of a 50-year site

curve, it is 115. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 157 cubic

feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Rock for road construction is not

readily available.

Cut and fill slopes tend to slump when wet. Steep skid

trails and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. A moderate reduction in

productivity can be expected to result from unmanaged

fires in undisturbed areas. Equipment and logs on the

surface result in a high degree of compaction when the soil

is moist and a moderate degree of puddling when the soil

is wet. Carefully laying out roads and skid trails, properly

timing their use, and using low-pressure ground equipment

can reduce the degree of compaction and puddling.

Seedling establishment and mortality are the main

concerns affecting timber production. The seedling

mortality rate is higher on ridgetops that are subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. A high soil temperature and a low

moisture content in the soil during the growing season can

cause seedling mortality. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily and reforestation by western hemlock and Douglas

fir occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This map unit is in capability subclass IVe.

19-Blethen gravelly loam, 30 to 60 percent slopes.

This very deep, well drained soil is on side slopes of

foothills. It formed in colluvium, glacial till, and slope

alluvium with an admixture of volcanic ash and loess. The

native vegetation is mainly conifers and shrubs. Elevation

is 500 to 1,400 feet. The average annual precipitation is

about 60 inches, the average annual air temperature is

about 47 degrees F, and the average frost-free period is

about 160 days.

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

leaves, and twigs 3 inches thick. When mixed to a depth of

6 inches, the surface layer is dark brown gravelly loam. The

upper 5 inches of the subsoil is dark brown gravelly loam.

The lower 7 inches is dark yellowish brown very gravelly

loam. The substratum to a depth of 60 inches is dark

yellowish brown and olive brown extremely gravelly sandy

loam. In some areas the surface layer is gravelly loam,

gravelly silt loam, or very gravelly silt loam. In other areas

the soil has less than 35 percent rock fragments in the

subsoil and substratum or is 40 to 60 inches deep to dense

glacial till or bedrock.

Included in this unit are small areas of Barneston,

Chuckanut, Heisler, Nati, Sehome, and Vanzandt soils,

soils that have serpentinitic mineralogy, slump areas, stony

areas, rock outcrop, and Blethen soils that have slopes of

more than 60 percent or less than 30 percent. Included

areas make up about 10 percent of the total acreage.

Permeability is moderate in the Blethen soil.

Available water capacity is high. The effective rooting depth

is 60 inches. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are salal,
Oregongrape, vine maple, red huckleberry, western

swordfern, longtube twinflower, and trailing blackberry.

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

index for Douglas fir is 149. On the basis of a 50-year site

curve, it is 115. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 157 cubic

feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. Cable yarding systems

generally are used on this unit. When timber is harvested,

the slope restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Unsurfaced roads are

slippery and soft when wet and are subject to deep rutting

during rainy periods. Rock for road construction is generally

not readily available. Cut and fill slopes tend to slump when

wet. Following road construction and clearcutting, road

failures and landslides are likely. Soil creep is common on

this unit. Locating roads on midslopes requires extensive

cutting and filling, which remove land from production.

Steep yarding paths, skid trails, and firebreaks are

subject to rifling and gullying unless adequate water bars

are provided or a protective plant cover is established. A

moderate reduction in productivity can be expected to result

from unmanaged fires in undisturbed areas.

Seedling establishment and mortality are the main

concerns affecting timber production. The seedling mortality

rate is higher on ridgetops that are subject to strong,

persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. A high soil temperature and a low

moisture content in the soil during the growing season can

cause seedling mortality. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily

and reforestation by western hemlock and Douglas fir

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This map unit is in capability subclass VIIe.

20-Blethen very bouldery loam, 5 to 40 percent

slopes. This very deep, well drained soil is on landslides

and toe slopes of foothills. It formed in colluvium, glacial

till, and slope alluvium with an admixture of volcanic ash

and loess. The native vegetation is mainly conifers and

shrubs. Elevation is 500 to 1,400 feet. The average

annual precipitation is

about 60 inches, the average annual air temperature is

about 47 degrees F, and the average frost-free period is

about 160 days.

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

leaves, and twigs 3 inches thick. When mixed to a depth of

6 inches, the surface layer is dark brown very bouldery

loam. The upper 3 inches of the subsoil is dark brown

extremely gravelly loam. The lower 19 inches is dark

yellowish brown extremely gravelly loam. The substratum to

a depth of 60 inches is olive brown and light olive brown

extremely cobbly loam. In some areas the surface layer is

bouldery loam, very stony loam, or very gravelly loam. In

other areas the depth to bedrock is 40 to 60 inches.

Included in this unit are small areas of Chuckanut, Nati,

and Squalicum soils, wet areas, landslides, and Blethen

soils that have slopes of more than 40 percent or less

than 5 percent. Included areas make up about 10 percent

of the total acreage.

Permeability is moderate in the Blethen soil. Available

water capacity is high. The effective rooting depth is 60

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

slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are red huckleberry,

Oregongrape, western swordfern, salal, vine maple,

longtube twinflower, trailing blackberry, and western

brackenfern.

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

index for Douglas fir is estimated to be 144. On the basis

of a 50-year site curve, it is estimated to be 110. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 150 cubic feet per acre per

year, occurring at age 60.

The main limitations affecting timber harvesting are the

surface boulders and the slope. The trees can break if they

are felled on the boulders, and yarding operations can be

hindered by the boulders. Unsurfaced roads are soft when

wet and are subject to deep rutting during rainy periods.

Rock for road construction is not readily available. Cut and

fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Steep skid trails and firebreaks are subject to

rilling and gullying unless adequate water bars are provided

or a protective plant cover is established. A moderate

reduction in productivity can be expected to result from

unmanaged fires in undisturbed areas.

Seedling establishment and mortality are the main

concerns affecting timber production. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. Because of the boulders, planting seedlings
by hand is difficult. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily

and reforestation by western hemlock and Douglas fir

occurs periodically. A high soil temperature and a low

moisture content in the soil during the growing season

can cause seedling mortality. When openings are made in

the canopy, the uncontrolled invasion and growth of

competing plants can delay the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means.

This map unit is in capability subclass VIs.

21-Borosaprists, 0 to 2 percent slopes. These very

deep, very poorly drained soils are in depressions on

mountains. They formed in mixed organic material

consisting of mosses, forbs, and shrubs over mineral

material. The native vegetation is mainly shrubs and forbs.

Elevation is 1,000 to 3,000 feet. The average annual

precipitation is about 75 inches, the average annual air

temperature is about 43 degrees F, and the average frostfree period is about 110 days.

No single profile is representative of this map unit. In

one of the more commonly observed ones, however, the

surface layer is very dark brown muck about 15 inches

thick. The next 45 inches is very dark brown muck. The

depth to mineral soil material ranges from 20 to more than

60 inches. After rubbing, the fiber content ranges from 5 to

15 percent. Reaction ranges from extremely acid to medium

acid. In some areas the surface layer is hemic material.

Included in this unit are small areas of mineral soils

that are ponded. Included areas make up about 5 percent

of the total acreage.

Permeability is moderate in the Borosaprists.

Available water capacity is high. The effective rooting

depth is limited by a seasonal high water table, which is

at or above the surface throughout the year. Runoff is

ponded, and there is no hazard of erosion. This unit is used

 for wildlife habitat.

This map unit is in capability subclass Vllw.

22-Briscot silt loam, drained, 0 to 2 percent slopes.

This very deep, poorly drained soil is on flood plains. It has

been artificially drained. It formed in alluvium. The native

vegetation is mainly trees and shrubs. Elevation is 20 to 50

feet. The average annual precipitation is about 45 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free period is about 170 days.

Typically, the surface layer is dark grayish brown silt

loam 9 inches thick. The underlying material to a depth of

60 inches is dark grayish brown, gray, and light brownish

gray, mottled, stratified silt loam, very fine sandy loam, fine

sand, and fine sandy loam. In some

areas the surface layer is very fine sandy loam, fine sandy

loam, or loam. In other areas the soil has a dark brown

surface layer, a silt loam underlying layer, or a sandy loam

underlying layer.

Included in this unit are small areas of Mt. Vernon and

Puyallup soils, undrained Briscot soils, Shalcar soils in

depressions, and small bodies of water. Included areas

make up about 10 percent of the total acreage.

Permeability is moderate in the Briscot soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1 to

3 feet from November through April. Runoff usually is very

slow, but the soil may be ponded during the winter. There

is no hazard of erosion. Downstream from Lynden, this soil

is subject to occasional brief periods of flooding from

December through February.

This unit is used mainly for hay and pasture or as

cropland. The included undrained Briscot soils are used as

woodland.

The main limitation in the areas used for hay and

pasture is the seasonal high water table. Proper stocking

rates, pasture rotation, and restricted grazing during wet

periods help to keep the pasture in good condition.

Grazing when the soil is wet results in compaction of the

surface layer and poor tilth. In areas where the drainage

system is not maintained or in areas which do not have

drainage, the water table limits the use of this unit to

grasses. The wetness limits the choice of plants and the

period of cutting or grazing and increases the risk of

winterkill.

This soil is suited to most crops commonly grown in the

survey area if adequate drainage systems are maintained.

These crops are peas, sweet corn, beans, and small grain.

Returning all crop residue to the soil and including grasses,

legumes, or grass-legume mixtures in the cropping

sequence help to maintain fertility and tilth. During the

growing season, the water table is artificially lowered to a

depth of about 3 to 5 feet. Tile drains and field ditches

should be maintained. They permit field operations to be

conducted earlier in the spring and increase yields of

perennial crops. In summer, irrigation is required for

maximum production.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, and black cottonwood. The common understory

plants are salmonberry, Douglas spirea, rose, stinging

nettle, and sedges.

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

index for red alder is 95. The highest average growth

rate in unmanaged, even-aged stands of red alder is 109

cubic feet per acre per year, occurring at age 40.

The main limitations affecting timber harvesting are
the occasional flooding and the muddiness caused by

seasonal wetness. The use of wheeled and tracked

equipment when the soil is wet causes excessive rutting.

Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and are subject to deep rutting during rainy periods. Rock

for road construction is not readily available. Extra rock is

needed to maintain a stable and uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table and the flooding hinder

root respiration and thus result in a low seedling survival

rate. Reforestation can be accomplished by planting red

alder or western redcedar seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the high water table and the hazard of

flooding. The wetness can be reduced by building the house

on a pad and by installing drainage tile around footings if a

suitable outlet is available. The main limitations on sites for

septic tank absorption fields are the seasonal high water

table and the hazard of flooding. Installing absorption lines

that are longer than normal and installing flood-control

structures help to overcome these limitations.

This map unit is in capability subclass Ilw.

23-Briscot, Oridia, and Sumas soils, 0 to 2 percent

slopes. This unit formed in alluvium on flood plains. The

native vegetation is mainly trees and shrubs. Elevation is

50 to 300 feet. The average annual precipitation is about

45 inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

This unit is 55 percent Briscot silt loam, 20 percent

Oridia silt loam, and 15 percent Sumas silt loam. The

components of this unit occur as areas so intricately

intermingled that mapping them separately was not

practical at the selected scale of mapping.

Included in this unit are small areas of drained

Briscot, Oridia, and Sumas soils and bodies of water.

Included areas make up about 10 percent of the total

acreage.

The Briscot soil is very deep and poorly drained.

Typically, the surface is covered with a mat of leaves and

twigs 2 inches thick. The upper 4 inches of the surface

layer is very dark grayish brown silt loam. The lower 8

inches is olive brown silt loam. The upper 25 inches of the

substratum is dark grayish brown and brown, mottled

loam. The lower part to a depth of 60 inches is fine sandy

loam. It is variegated but is dominantly dark grayish

brown. In some areas the soil has sand in the substratum

or has stratified sand and silt in the substratum.

Permeability is moderate in the Briscot soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at or near the

surface from November through May. This soil is subject to

frequent, brief periods of flooding from November through

April. Channeling and deposition are common along

streambanks.

The Oridia soil is very deep and poorly drained.

Typically, the surface layer is very dark grayish brown silt

loam 12 inches thick. The upper 12 inches of the

underlying material is dark grayish brown, mottled silt loam.

The next 16 inches is gray, mottled silt loam. The lower

part to a depth of 60 inches is gray silt loam. In some

areas the soil has stratified sand and silt in the substratum

or has 18 to 35 percent clay in the substratum.

Permeability is moderate in the Oridia soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at or near the

surface from November through May. This soil is subject to

frequent, brief periods of flooding from November through

April. Channeling and deposition are common along

streambanks.

The Sumas soil is very deep and poorly drained.

Typically, the surface layer is dark brown silt loam 8

inches thick. The upper 10 inches of the underlying

material is grayish brown, mottled silt loam. The lower

part to a depth of 60 inches is dominantly very dark

grayish brown sand.

Permeability is moderate in the upper part of the Sumas

soil and rapid in the lower part of the underlying material.

Available water capacity is moderate. The effective rooting

depth is limited by a seasonal high water table, which is at

or near the surface from November through May. This soil

is subject to frequent, brief periods of flooding from

November through April. Channeling and depositions are

common along streambanks.

This unit is used as woodland. Red alder is the main
woodland species. Among the trees of limited extent are

western redcedar and black cottonwood. The common

understory plants are salmonberry, Douglas spirea, rose,

stinging nettle, and sedges.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitations affecting timber harvesting are the

frequent flooding and the muddiness caused by seasonal

wetness. The use of wheeled and tracked equipment when

the soils are wet causes excessive rutting. Using lowpressure ground equipment can minimize damage to the

soils. Unsurfaced roads are soft when wet and are subject

to deep rutting during rainy periods. Rock for road

construction is not readily available. Extra rock is needed

to maintain a stable and uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soils are moist and a high

degree of puddling when the soils are wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The seasonal high water table and the flooding

hinder root respiration and thus result in a low seedling

survival rate. Reforestation can be accomplished by

planting red alder or western redcedar seedlings. If seed

trees are available, natural reforestation of cutover areas

by red alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the seasonal high water table, trees are frequently subject

to windthrow when the soils are wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the seasonal high water table and the hazard

of flooding. The wetness can be reduced in some areas by

diversions, which intercept water, and by open ditches,

which remove excess water. It also can be reduced by

building the house on a pad and by installing drainage tile

around footings if a suitable outlet is available. The main

limitations on sites for septic tank absorption fields are the

seasonal high water table and the hazard of flooding.

Installing the absorption field in fill approved by the health

district helps to compensate for the moderate permeability

in the Sumas soil. Flood-control structures are needed.

The Briscot, Oridia, and Sumas soils are in capability

subclass VIw.

24-Chuckanut loam, 3 to 8 percent slopes. This very

deep, well drained soil is on toe slopes of foothills. It

formed in a mixture of volcanic ash and colluvium derived

from glacial drift and sandstone. The native vegetation is

mainly conifers and shrubs. Elevation is 250 to 450 feet.

The average annual precipitation is about 50 inches, the

average annual air temperature is about 49 degrees F, and

the average frost-free period is about 160 days.

Typically, the surface layer is dark brown loam 10

inches thick. The upper 2 inches of the subsoil is olive

brown sandy loam. The lower 12 inches is dark brown

gravelly loam. The substratum to a depth of 60 inches is

olive brown gravelly sandy loam with 60 percent

weathered rock fragments. In some areas the surface layer

is sandy loam or silt loam. In other areas the soil has 20

to 50 percent weathered rock fragments in the subsoil or

is 40 to 60 inches deep to sandstone.

Included in this unit are small areas of Squalicum,

Briscot, and Puyallup soils and small areas of Chuckanut

soils that have slopes of more than 8 percent or less than 3

percent. Included areas make up about 10 percent of the

total acreage.

Permeability is moderate in the Chuckanut soil.

Available water capacity is high. The effective rooting

depth is 60 inches. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used mainly for hay and pasture. It also is

used as woodland and as a site for homes.

This unit is suited to hay and pasture. It has few

limitations. Proper stocking rates, pasture rotation, and

restricted grazing during short wet periods help to keep the

pasture in good condition. This unit also is suited to other

climatically adapted crops. In summer, irrigation is required

for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder, and

western redcedar. The common understory plants are

western swordfern, red huckleberry, Oregongrape, western

brackenfern, and salal.

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

index for Douglas fir is 173. On the basis of a 50-year site

curve, it is 130. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 184 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Rock for road construction is not readily

available.

Equipment and logs on the surface result in a high
degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily and reforestation by western hemlock occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This unit is suited to homesite development. It has few

limitations. Moderate erosion is likely to occur on

unprotected construction sites. Installing the absorption

field in fill approved by the health district helps to

compensate for the moderate permeability of this soil.

This map unit is in capability subclass Ile.

25-Chuckanut loam, bedrock substratum, 5 to 15

percent slopes. This deep, well drained soil is on toe

slopes of foothills. It formed in a mixture of volcanic ash

and colluvium derived from glacial drift and sandstone. The

native vegetation is mainly conifers and shrubs. Elevation

is 300 to 1,400 feet. The average annual precipitation is

about 40 inches, the average annual air temperature is

about 49 degrees F, and the average frost-free period is

about 160 days.

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

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

brown loam 6 inches thick. The upper 4 inches of the

subsoil is dark yellowish. brown loam. The lower 21 inches

is light olive brown gravelly loam. The substratum is light

olive brown gravelly loam 17 inches thick. It is underlain

by sandstone at a depth of 48 inches. The depth to

sandstone ranges from 40 to 60 inches. The content of

weathered rock fragments ranges from 35 to 60 percent

throughout this profile. In some areas the surface layer is

gravelly loam or sandy loam. In other areas the soil is

more than 60 inches deep to sandstone or is 40 to 60

inches deep to siltstone or conglomerate.

Included in this unit are small areas of Nati and

Squalicum soils, Bellingham soils in depressions, and

Chuckanut soils that have slopes of more than 15 percent

or less than 5 percent. Included areas make up about 10

percent of the total acreage.

Permeability is moderate in the Chuckanut soil. Available

water capacity is high. The effective rooting depth is 40 to

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

is slight.

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

hay and pasture and as a site for homes.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, and Pacific madrone. The common

understory plants are western swordfern, red huckleberry,

Oregongrape, western brackenfern, and salal.

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

index for Douglas fir is 161. On the basis of a 50-year site

curve, it is 119. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 171 cubic

feet per acre per year, occurring at age 65.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Sandstone, a poor-quality rock for road

construction, is readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. A moderate reduction

in productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

The main limitation in the areas used for hay and

pasture is the hazard of erosion. Proper stocking rates,

pasture rotation, and restricted grazing during short wet

periods help to keep the pasture in good condition and help

to control runoff and water erosion during periods of

reestablishment.

The main limitation affecting homesite development is

the slope. The main limitations on sites for septic tank

absorption fields are the depth to bedrock, the moderate

permeability, and the slope. These limitations can be

overcome by using interceptor drains, by installing the

absorption field at a shallow depth, and by installing

absorption lines that are longer than normal and that are on

the contour. During the rainy season, the effluent from

onsite sewage disposal systems can seep at points

downslope.

This map unit is in capability subclass Ille.
26-Chuckanut loam, bedrock substratum, 15 to 30

percent slopes. This deep, well drained soil is on toe

slopes and side slopes of foothills. It formed in a mixture of

volcanic ash and colluvium derived from glacial drift and

sandstone. The native vegetation is mainly conifers and

shrubs. Elevation is 300 to 1,400 feet. The average annual

precipitation is about 40 inches, the average annual air

temperature is about 49 degrees F, and the average frostfree period is about 160 days.

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

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

brown loam 6 inches thick. The upper 4 inches of the

subsoil is dark yellowish brown loam. The lower 21 inches

is light olive brown gravelly loam. The substratum is light

brown gravelly loam 17 inches thick. It is underlain by

sandstone at a depth of 48 inches. The depth to sandstone

ranges from 40 to 60 inches. The content of weathered

rock fragments ranges from 35 to 60 percent throughout

this profile. In some areas the surface layer is gravelly

loam or sandy loam. In other areas the soil is more than 60

inches deep to sandstone or is 40 to 60 inches deep to

siltstone or conglomerate.

Included in this unit are small areas of Nati and

Squalicum soils, Bellingham soils in depressions, and

Chuckanut soils that have slopes of more than 30

percent or less than 15 percent. Included areas make up

about 10 percent of the total acreage.

Permeability is moderate in the Chuckanut soil. Available

water capacity is high. The effective rooting depth is 40 to

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

is slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and Pacific

madrone. The common understory plants are western

swordfern, red huckleberry, Oregongrape, western

brackenfern, and salal.

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

index for Douglas fir is 161. On the basis of a 50-year site

curve, it is 119. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 171 cubic

feet per acre per year, occurring at age 65.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Sandstone, a poor-quality rock for road

construction, is readily available. Cut and fill slopes tend to

slump when wet. Following road construction and

clearcutting, road failures and landslides are likely.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Steep

skid trails and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. Carefully laying out roads and

skid trails, properly timing their use, and using lowpressure ground equipment can reduce the degree of

compaction, puddling, and erosion. A moderate reduction

in productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by western hemlock occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass IVe.

27-Chuckanut loam, bedrock substratum, 30 to 60

percent slopes. This deep, well drained soil is on side

slopes of foothills. It formed in a mixture of volcanic ash

and colluvium derived from glacial drift and sandstone. The

native vegetation is mainly conifers and shrubs. Elevation

is 300 to 1,400 feet. The average annual precipitation is

about 40 inches, the average annual air temperature is

about 49 degrees F, and the average frost-free period is

about 160 days.

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

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

brown loam 3 inches thick. The subsoil is dark yellowish

brown gravelly loam 14 inches thick. The substratum is

yellowish brown gravelly sandy loam 35 inches thick.

Sandstone is at a depth of about 52 inches. The depth to

sandstone ranges from 40 to 60 inches. The content of

weathered rock fragments ranges from 35 to 60 percent

throughout this profile. In some areas the surface layer is

gravelly loam or sandy loam. In other areas the soil has a

thicker surface layer, is more than 60 inches deep to

sandstone, or is 40 to 60 inches deep to siltstone or

conglomerate.

Included in this unit are small areas of Nat! and

Squalicum soils, Bellingham soils in depressions, and

Chuckanut soils that have slopes of more than 60

percent or less than 30 percent. Included areas make up

about 10 percent of the total acreage.

Permeability is moderate in the Chuckanut soil.

Available water capacity is high. The effective rooting

depth is 40 to 60 inches. Runoff is medium, and the
hazard of water erosion is moderate.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and Pacific

madrone. The common: understory plants are western

swordfern, red huckleberry, Oregongrape, western

brackenfern, and salal.

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

index for Douglas fir is 161. On the basis of a 50-year site

curve, it is 119. The highest average growth rate in

unmanaged, even-aged stands' of Douglas fir is 171 cubic

feet per acre per year, occurring at age 65.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is harvested,

the slope restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Unsurfaced roads are

soft when wet and are subject to deep rutting during rainy

periods. Sandstone, a poor-quality rock for road

construction, is readily available. Cut and fill slopes tend to

slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Steep

yarding paths, skid trails, and firebreaks are subject to

rilling and gullying unless adequate water bars are provided

or a protective' plant cover is established. Carefully laying

out roads and cable yarding paths, properly timing their

use, and using cable systems that lift logs entirely off the

ground can reduce the degree of compaction, puddling,

and erosion. A moderate reduction in productivity can be

expected to result from unmanaged fires in undisturbed

areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by western hemlock occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass VIle.

28-Chuckanut-Shalcar complex, 0 to 15 percent

slopes. This map unit is on toe slopes of foothills and

landslides. Slopes are hummocky. The Chuckanut soil

is on slopes, and the Shalcar soil is in depressions. The

areas of Shalcar soil are irregular in shape and are 0.25

acre to 5 acres in size. The native vegetation is mainly

conifers and shrubs on the Chuckanut soil and shrubs and

forbs on the Shalcar soil. Elevation is 250 to 500 feet. The

average annual precipitation is about 50 inches, the

average annual air temperature is about 49 degrees F,

and the average frost-free period is about 160 days.

This unit is 75 percent Chuckanut loam and 10 percent

Shalcar muck. The Chuckanut soil has slopes of 3 to 15

percent, and the Shalcar soil has slopes of 0 to 2

percent. The components of this unit occur as areas so

intricately intermingled that mapping them separately was

not practical at the selected scale of mapping.

Included in this unit are small areas of Nati soils on

ridges of foothills; Bellingham soils in depressions; deep,

organic soils in depressions; Chuckanut soils that have

slopes of more than 15 percent; and bouldery areas.

Included areas make up about 15 percent of the total

acreage.

The Chuckanut soil is very deep and well drained. It

formed in a mixture of volcanic ash and colluvium derived

from glacial drift and sandstone. Typically, the surface is

covered with a mat of needles, leaves, and twigs 1 inch

thick. The surface layer is very dark brown loam 4 inches

thick. The upper 11 inches of the subsoil is dark yellowish

brown gravelly loam. The lower 6 inches is olive brown

gravelly loam. The upper 10 inches of the substratum is

olive brown gravelly loam. The lower part to a depth of 60

inches is dark grayish brown gravelly loam. The content of

weathered rock fragments ranges from 35 to 60 percent

throughout this profile. In some areas the surface layer is

sandy loam or silt loam. In other areas the soil has

sandstone at a depth of 40 to 60 inches.

Permeability is moderate in the Chuckanut soil.

Available water capacity is high. The effective rooting

depth is 60 inches. Runoff is slow, and the hazard of

water erosion is slight.

The Shalcar soil is very deep and very poorly drained. It

formed in mixed organic material consisting of mosses,

forbs, and shrubs over alluvium. Typically, the surface layer

is very dark brown muck 18 inches thick. The underlying

material to a depth of 60, inches, is dark gray loam. In some

areas the surface layer is mucky silt loam. In other areas

the underlying material is silt loam or sandy loam.

Permeability is moderate in the Shalcar soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at or above the

surface from October through May. Runoff is ponded, and

there is no hazard of erosion.
The Chuckanut soil is used mainly as woodland. It

also is used as a site for homes. The Shalcar soil is used

for wildlife habitat.

Douglas fir is the main woodland species on the

Chuckanut soil. Among the trees of limited extent are

western hemlock, red alder, and western redcedar. The

common understory plants are western swordfern, red

huckleberry, Oregongrape, western brackenfern, and salal.

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

index for Douglas fir is estimated to be 173 on the

Chuckanut soil. On the basis of a 50-year site curve, it is

estimated to be 130. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is about 184

cubic feet per acre per year, occurring at age 60.

Red alder is the main woodland species on the

Shalcar soil. Among the trees of limited extent are

western redcedar, western hemlock, lodgepole pine,

and Sitka spruce. The common understory plants

include salmonberry, Douglas spirea, rose, stinging

nettle, and sedges.

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

index for red alder is estimated to be 85 on the Shalcar

soil. The highest average growth rate in unmanaged, evenaged stands of red alder is about 92 cubic feet per acre per

year, occurring at age 40.

The main limitations affecting timber harvesting are the

ponding on the Shalcar soil, the muddiness caused by

seasonal wetness on the Chuckanut soil, and the

hummocky topography. The ponding hinders the use of

ground equipment and hinders timber harvesting.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soils are moist and a

moderate degree of puddling when the soils are wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling. A moderate

reduction in productivity can be expected to result from

unmanaged fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production on the Chuckanut soil. Seedling

mortality, seedling establishment, and the hazard of

windthrow are the main concerns on the Shalcar soil.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings on the Chuckanut soil and western

redcedar or red alder seedlings on the Shalcar soil. The

ponding on the Shalcar soil makes planting seedlings by

hand difficult. The high water table on the Shalcar soil

hinders root respiration and thus results in a low seedling

survival rate. If seed trees are available, natural

reforestation of cutover areas by red alder

occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means.

Because the rooting depth is restricted by the high water

table, trees on the Shalcar soil are frequently subject to

windthrow when the soil is wet and winds are strong.

The main limitations affecting homesite development are

the slope of the Chuckanut soil and the high water table

and low strength of the Shalcar soil. Effluent from

absorption fields can surface in downslope areas and

create a health hazard. The moderate permeability in the

Chuckanut soil and the high water table in the Shalcar soil

increase the likelihood that the absorption field will fail.

The Chuckanut soil is in capability subclass Ille. The

Shalcar soil is in capability subclass VIw.

29-Chuckanut-Urban land complex, 5 to 20 percent

slopes. This map unit is on toe slopes of foothills. The

native vegetation is mainly conifers and shrubs. Elevation is

20 to 500 feet. The average annual precipitation is about

35 inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

This unit is 50 percent Chuckanut loam and 35 percent

Urban land. The components of this unit occur as areas

so intricately intermingled that mapping them separately

was not practical at the selected scale of mapping.

Included in this unit are small areas of Nati, Everett,

Squalicum, and Whatcom soils, Bellingham and Labounty

soils in depressions, and Chuckanut soils that have slopes

of more than 20 percent or less than 5 percent. Included

areas make up about 15 percent of the total acreage.

The Chuckanut soil is very deep and well drained. It

formed in a mixture of volcanic ash and colluvium derived

from glacial drift and sandstone. When mixed to a depth of

6 inches, the surface layer is dark brown loam. The upper

4 inches of the subsoil is dark yellowish brown gravelly

loam. The lower 21 inches is light olive brown gravelly

loam. The substratum is light olive brown gravelly loam 17

inches thick. It is underlain by sandstone at a depth of 48

inches. The depth to sandstone ranges from 40 to 60

inches. The content of weathered rock fragments ranges

from 35 to 60 percent throughout this profile. In some

areas the surface layer is gravelly loam or sandy loam. In

other areas the soil is more than 60 inches deep to

sandstone.

Permeability is moderate in the Chuckanut soil.
Available water capacity is high. The effective rooting

depth is 40 to 60 inches. Runoff is medium, and the

hazard of water erosion is moderate.

The Urban land consists of areas covered by streets,

buildings, parking lots, and other structures that so obscure

the soils that identification of the soil series is not feasible.

The Chuckanut soil is used for lawns, gardens,

parks, or vacant lots. It is highly erodible during

construction and on cut and fill slopes.

If this unit is used for homesite development, the main

limitation is the slope. The main limitations on sites for

septic tank absorption fields are the slope, the moderate

permeability, and the depth to bedrock. These limitations

can be overcome by using interceptor drains, by installing

the absorption field at a shallow depth, and by installing

absorption lines that are longer than normal and that are on

the contour. During the rainy season, the effluent from

onsite sewage disposal systems can seep at points

downslope.

The Chuckanut soil is in capability subclass Ille. The

Urban land is in capability subclass VIlls.

30-Clendenen gravelly silt loam, 5 to 30 percent

slopes. This shallow, moderately well drained soil is on

mountain shoulder slopes and back slopes. It formed in a

mixture of volcanic ash, loess, and colluvium and glacial

till. The native vegetation is mainly conifers and shrubs.

Elevation is 3,200 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 frostfree period is about 100 days.

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

leaves, and twigs 7 inches thick. When mixed to a depth of

5 inches, the surface layer is strong brown gravelly silt

loam. The subsoil is strong brown very gravelly silt loam 11

inches thick. Dense glacial till that crushes to very gravelly

loam is at a depth of 16 inches. The depth to dense glacial

till ranges from 14 to 20 inches. The dense glacial till is

similar to a cemented pan. In some areas the surface layer

is very gravelly silt loam, silt loam, or gravelly loam. In

other areas the soil has dunite rock fragments in the

subsoil or is 20 to 30 inches deep to dense glacial till.

Included in this unit are small areas of Edfro, Diobsud,

Crinker, and Hinker soils, soils that are shallow to bedrock

or very shallow to dense glacial till, and Clendenen soils

that have slopes of more than 30 percent or less than 5

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the

Clendenen soil and very slow in the dense glacial till.

Available water capacity is low. The effective rooting depth

is 14 to 20 inches. Runoff is slow, and the hazard

of water erosion is slight. Water is perched above the

dense glacial till from November through June.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are. Pacific silver fir, mountain hemlock, and western

redcedar. The common understory plants are tall blue

huckleberry, bunchberry dogwood, western brackenfern,

and deer fern.

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

index for western hemlock is estimated to be 105. On the

basis of a 50-year site curve, it is estimated to be 75. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 151 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal wetness.

During an average year, the snowpack limits the use of

equipment and restricts access from November through

May. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Steep

skid trails and fire breaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. Carefully laying out roads and

skid trails, properly timing their use, and using low-pressure

ground equipment can reduce the degree of compaction

and puddling.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. The seasonal

wetness hinders root respiration and thus results in a low

seedling survival rate. A low soil temperature, deep

snowpack, and a short growing season also hinder the

survival of planted and natural seedlings and delay their

establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting western hemlock or Pacific silver fir seedlings.

If seed trees are available, natural reforestation of cutover

areas by western hemlock and Pacific silver fir occurs

periodically. Because the rooting depth is restricted by the

dense glacial till, trees are frequently subject to windthrow

when the soil is wet and winds are strong.

This map unit is in capability subclass Vle.
31-Clipper silt loam, drained, 0 to 2 percent slopes.

This very deep, somewhat poorly drained soil is in

depressions on outwash terraces and outwash plains. It

has been artificially drained. It formed in an admixture of

loess and volcanic ash over glacial outwash. The native

vegetation is mainly trees and shrubs. Elevation is 50 to

300 feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface layer is very dark grayish

brown silt loam 9 inches thick. The upper 9 inches of the

subsoil is grayish brown and gray, mottled silt loam. The

lower 12 inches is grayish brown, gray, and yellowish

brown, mottled gravelly sandy loam. The substratum to a

depth of 60 inches is dark grayish brown and grayish

brown, mottled very gravelly loamy sand. The depth to very

gravelly loamy sand or sand ranges from 14 to 30 inches.

In some areas the surface layer is loam or gravelly silt

loam. In other areas the soil has a substratum of very

gravelly sandy loam, gravelly sand, or gravelly sandy loam.

Included in this unit are small areas of Birchbay,

Kickerville, and Whitehorn soils, undrained Clipper soils,

and soils that are similar to the Clipper soil but have 18 to

25 percent clay in the subsoil or have a hardpan of

glaciomarine drift at a depth of 40 to 60 inches. Included

areas make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the Clipper

soil and rapid in the substratum. Available water capacity is

moderate. The effective rooting depth is limited by a

seasonal high water table, which is at a depth of 2 to 4 feet

from November through April. Runoff usually is very slow,

but the soil may be ponded during the winter. There is no

hazard of erosion.

This unit is used mainly for hay and pasture or as

cropland. It also is used as woodland and as a site for

homes. The included undrained Clipper soils are used as

woodland.

The main limitations for hay and pasture are the

seasonal high water table and the moderate available

water capacity. Proper stocking rates, pasture rotation, and

restricted grazing during wet periods help to keep the

pasture in good condition. Grazing when the soil is wet

results in compaction of the surface layer and poor tilth.

The water table limits the use of this unit to grasses

unless a drainage system is installed. The wetness limits

the choice of plants and the period of cutting or grazing

and increases the risk of winterkill.

The main limitations in the areas used as cropland are

the seasonal high water table and the moderate available

water capacity. The principal crops are small grain and

corn silage. This unit is well suited to most

crops commonly grown in the survey area if adequate

drainage systems are maintained. It also is suited to

other climatically adapted crops.

During the growing season, the water table is artificially

lowered to a depth of about 3 to 5 feet. Tile drains and field

ditches should be maintained. They permit field operations

to be conducted earlier in the spring and increase yields of

perennial crops. Most crops common to the area can be

grown if the drainage system is adequate. In summer,

irrigation is required for maximum production.

Red alder is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, and Douglas fir. The common understory plants

are salmonberry, western brackenfern, red huckleberry,

western swordfern, trailing blackberry, and sweetscented

bedstraw.

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

index for red alder is estimated to be 95. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 109 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Rock for road construction is not

readily available. Extra rock is needed to maintain a stable,

uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are present,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be
reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

In shallow excavations special retainer walls may be

needed to keep cutbanks from caving. The main limitations

on sites for septic tank absorption fields are the seasonal

high water table and a poor filtering capacity. Installing

absorption lines that are longer than normal helps to

overcome these limitations. If used as a base for roads

and streets, the soil can be mixed with the underlying

sand and gravel, which can increase the strength and

stability of the soil.

This map unit is in capability subclass Ilw.

32-Comar silt loam, 5 to 15 percent slopes. This

deep, moderately well drained soil is on toe slopes of

foothills. It formed in a mixture of volcanic ash and slope

alluvium and colluvium derived from siltstone and glacial

till. The native vegetation is mainly conifers and shrubs.

Elevation is 300 to 1,500 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

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

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

dark grayish brown silt loam 5 inches thick. The subsoil is

dark yellowish brown silt loam 16 inches thick. The

substratum is light olive brown silt loam 19 inches thick.

Siltstone is at a depth of about 40 inches. The depth to

siltstone ranges from 40 to 60 inches. In some areas the

soil has a gravelly subsoil, is more than 60 inches deep to

siltstone, or is 40 to 60 inches deep to sandstone.

Included in this unit are small areas of Nati, Sehome,

and Squalicum soils, Bellingham soils in depressions,

bouldery areas, and Comar soils that have slopes of more

than 15 percent or less than 5 percent. Included areas

make up about 10 percent of the total acreage.

Permeability is moderately slow in the Comar soil.

Available water capacity is moderate. The effective rooting

depth is 40 to 60 inches. A seasonal high water table

fluctuates in depth from 1.5 to 3.5 feet in January and

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

is slight.

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

for hay and pasture and as a site for homes.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder, and

western redcedar. The common understory plants are vine

maple, western swordfern, red huckleberry, salal, western

brackenfern, and Oregongrape.

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

index for Douglas fir is 148. On the basis of a 50-year site

curve, it is 116. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 156

cubic feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Siltstone, a poor-quality rock for road

construction, is readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling. A moderate reduction

in productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

The main limitation in the areas used for hay and

pasture is the hazard of erosion during periods of

reestablishment. Proper stocking rates, pasture rotation,

and restricted grazing during short wet periods help to

keep the pasture in good condition and help to control

runoff during periods of reestablishment.

The main limitations affecting homesite development are

the seasonal high water table and the slope. The deep cuts

needed to provide essentially level building sites can

expose bedrock. The main limitations on sites for septic

tank absorption fields are the seasonal high water table

and the moderately slow permeability. These limitations

can be overcome by using interceptor drains, by installing

the absorption field at a shallow depth, and by installing

absorption lines that are longer than normal and that are

on the contour. The slope affects the installation of septic

tank absorption fields.

This map unit is in capability subclass Ille.

33-Comar silt loam, 15 to 30 percent slopes. This

deep, moderately well drained soil is on toe slopes and

side slopes of foothills. It formed in a mixture of volcanic

ash and slope alluvium and colluvium derived from

siltstone and glacial till. The native vegetation is mainly

conifers and shrubs. Elevation is 300 to 1,500 feet. The

average annual precipitation is about 55 inches, the

average annual air temperature is about 47 degrees F,

and the average frost-free period is about 160 days.

Typically, the surface is covered with a mat of
needles, leaves, and twigs 2 inches thick. The surface layer

is very dark grayish brown silt loam 5 inches thick. The

subsoil is dark yellowish brown silt loam 16 inches thick.

The substratum is light olive brown silt loam 19 inches

thick. It has 15 percent weathered rock fragments. Siltstone

is at a depth of about 40 inches. The depth to siltstone

ranges from 40 to 60 inches. In some areas the soil has a

gravelly subsoil, is more than 60 inches deep to siltstone,

or is 40 to 60 inches deep to sandstone or conglomerate.

Included in this unit are small areas of Nati, Sehome,

and Squalicum soils, Bellingham soils in depressions,

bouldery areas, and Comar soils that have slopes of more

than 30 percent or less than 15 percent. Included areas

make up about 10 percent of the total acreage.

Permeability is moderately slow in the Comar soil.

Available water capacity is moderate. The effective rooting

depth is 40 to 60 inches. A seasonal high water table

fluctuates in depth from 1.5 to 3.5 feet in January and

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

slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, and western redcedar. The

common understory plants are vine maple, western

swordfern, red huckleberry, salal, western brackenfern, and

Oregongrape.

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

index for Douglas fir is 148. On the basis of a 50-year site

curve, it is 116. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 156 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Siltstone, a poor-quality rock for road

construction, is readily available. Cut and fill slopes tend to

slump when wet. Following road construction and

clearcutting, road failures and landslides are likely.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Steep skid trails

and firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established. Carefully laying out roads and skid

trails, properly timing their use, and using low-pressure

ground equipment can reduce the degree of compaction,

puddling, and erosion. A moderate reduction in productivity

can be expected to result from unmanaged fires in

undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds

than in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by western hemlock occurs periodically.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass IVe.

34-Comar silt loam, 30 to 60 percent slopes. This

deep, moderately well drained soil is on toe slopes and

side slopes of foothills. It formed in a mixture of volcanic

ash and slope alluvium and colluvium derived from siltstone

and glacial till. The native vegetation is mainly conifers and

shrubs. Elevation is 300 to 1,500 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 5 inches thick. The surface layer is dark

brown silt loam 5 inches thick. The subsoil is brown silt

loam 11 inches thick. The substratum is light olive brown

silt loam 28 inches thick. Siltstone is at a depth of about 44

inches. The depth to siltstone ranges from 40 to 60 inches.

In some areas the soil is 40 to 60 inches deep to

sandstone or conglomerate.

Included in this unit are small areas of Nati, Sehome,

and Squalicum soils, Bellingham soils in depressions,

bouldery areas, and Comar soils that have slopes of more

than 60 percent or less than 30 percent. Included areas

make up about 10 percent of the total acreage.

Permeability is moderately slow in the Comar soil.

Available water capacity is moderate. The effective rooting

depth is 40 to 60 inches. A seasonal high water table

fluctuates in depth from 1.5 to 3.5 feet in January and

February. Runoff is medium,. and the hazard of water

erosion is moderate.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, and western redcedar. The

common understory plants are vine maple, western

swordfern, red huckleberry, salal, western brackenfern, and

Oregongrape.

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

index for Douglas fir is 148. On the basis of a 50-year site

curve, it is 116. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 156 cubic

feet per acre per year, occurring at age 60.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is
harvested, the slope restricts the use of wheeled and

tracked equipment in skidding operations. Cable yarding

systems generally are safer and disturb the surface less

extensively. Unsurfaced roads are soft when wet and are

subject to deep rutting during rainy periods. Siltstone, a

poor-quality rock for road construction, is readily available.

Cut and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Steep yarding

paths, skid trails, and firebreaks are subject to rilling and

gullying unless adequate water bars are provided or a

protective plant cover is established. Carefully laying out

roads and cable yarding paths, properly timing their use,

and using cable systems that lift logs entirely off the

ground can reduce the degree of compaction, puddling,

and erosion. A moderate reduction in productivity can be

expected to result from unmanaged fires in undisturbed

areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by western hemlock occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass Vlle.

35-Crinker very channery silt loam, 30 to 60 percent

slopes. This moderately deep, well drained soil is on high

mountain back slopes and shoulder slopes. It formed in an

admixture of volcanic ash and slope alluvium, colluvium,

and glacial till derived dominantly from phyllite. The native

vegetation is mainly conifers and shrubs. Elevation is

2,600 to 3,600 feet. The average annual precipitation is

about 90 inches, the average annual air temperature is

about 42 degrees F, and the average frost-free period is

about 100 days.

Typically, the surface is covered with a mat of

decomposed needles, leaves, and twigs 6 inches thick.

When mixed to a depth of 6 inches, the surface layer is

dark brown very channery silt loam. The upper 3 inches of

the subsoil is organic stained, strong brown very channery

silt loam. The lower 15 inches is yellowish

brown very channery silt loam. Phyllite is at a depth of

about 24 inches. The depth to phyllite ranges from 20 to 40

inches. In some areas the surface layer is channery silt

loam or channery loam. In other areas the soil has a less

developed subsoil, has less than 6 percent organic carbon

throughout the subsoil, is 14 to 20 or 40 to 60 inches deep

to phyllite, or does not have the subsurface layer.

Included in this unit are small areas of Wollard, Diobsud,

Clendenen, and Saar soils, Rock outcrop, and Crinker

soils that have slopes of more than 60 percent. Included

areas make up about 20 percent of the total acreage.

Permeability is moderate in the Crinker soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is medium, and the hazard of

water erosion is moderate.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

is Pacific silver fir. The common understory plants are tall

blue huckleberry, salmonberry, bunchberry dogwood,

western brackenfern, and deer fern.

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

index for western hemlock is 119. On the basis of a 50-

year site curve, it is 83. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 178

cubic feet per acre per year, occurring at age 50. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the hazard of erosion, and the slope. During an

average year, the snowpack limits the use of equipment

and restricts access from November through April. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less

extensively. Because most of the roots are concentrated in

the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Phyllite, a

poor-quality rock for road construction, is readily available.

Extra rock is needed to maintain a stable, uniform road

surface. Cut and fill slopes tend to slump when wet.

Following road construction and clearcutting, road failures

and landslides are likely. Soil creep is common on this

unit.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and cable
yarding paths, properly timing their use, and using cable

systems that lift logs entirely off the ground reduce the

hazard of erosion.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock, noble fir, or

Pacific silver fir seedlings. If seed trees are available,

natural reforestation of cutover areas by western hemlock

and Pacific silver fir occurs periodically. Because the

rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIIe.

36-Cupples gravelly loam, 5 to 30 percent slopes.

This moderately deep, moderately well drained soil is on

mountain back slopes and plateaus. It formed in a mixture

of volcanic ash and loess over glacial till. The native

vegetation is mainly conifers and shrubs. Elevation is 1,000

to 2,000 feet. The average annual precipitation is about 70

inches, the average annual air temperature is about 44

degrees F, and the average frost-free period is about 120

days.

Typically, the surface is covered with a mat of needles

and twigs 7 inches thick. When mixed to a depth of 10

inches, the surface layer is dark brown gravelly loam. The

subsoil is olive brown and dark yellowish brown very

gravelly loam 20 inches thick. Dense glacial till that crushes

to very gravelly sandy loam is at a depth of 30 inches. The

depth to dense glacial till ranges from 20 to 40 inches. The

dense glacial till is similar to a cemented pan. In some

areas the surface layer is gravelly silt loam. In other areas

the soil has more than 35 percent weathered rock

fragments within the subsoil, has less than 35 percent rock

fragments within the subsoil, is 40 to 60 inches deep to

dense glacial till, or has a less developed subsoil.

Included in this unit are small areas of Revel,

Welcome, Rinker, and Oakes soils, soils that are less

than 30 inches deep to dense glacial till, and Cupples

soils that have slopes of more than 30 percent or less

than 5 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the upper part of the

Cupples soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from December through

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

slight.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are western

swordfern, deer fern, red huckleberry, western brackenfern,

longtube twinflower, and vine maple.

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

index for western hemlock is143. On the basis of a 50-year

site curve, it is 110. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 224

cubic feet per acre per year, occurring at age 50. On the

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

Douglas fir is estimated to be 154. On the basis of a 50-

year site curve, it is estimated to be 118. The highest

average growth rate in unmanaged, even-aged stands of

Douglas fir is about 163 cubic feet per acre per year,

occurring at age 60. Areas on ridgetops that are subject to

strong, persistent winds are less productive than the other

areas of this unit.

The main limitations affecting timber harvesting are the

muddiness caused by seasonal wetness and occasional

snowpack. During an average year, the snowpack limits the

use of equipment and restricts access from January

through March. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and are subject to deep rutting during rainy

periods. Rock for road construction is not readily available.

Cut and fill slopes tend to slump when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling. Steep

yarding paths, skid trails, and firebreaks are subject to

rilling and gullying unless adequate water bars are

provided or a protective plant cover is established. .

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. A low content of moisture in the surface layer

during the growing season hinders the survival of planted

and naturally established seedlings. The seedling mortality

rate is higher on ridgetops that are subject to strong,

persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Douglas fir seedlings. If seed trees are

available, natural reforestation of cutover
areas by western hemlock occurs readily and reforestation

by. Douglas fir and red alder occurs periodically. When

openings are made in the canopy, the uncontrolled invasion

and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the dense glacial till, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass IVe.

37-Cupples gravelly loam, 30 to 60 percent slopes.

This moderately deep, moderately well drained soil is on

mountain back slopes. It formed in a mixture of volcanic

ash and loess over glacial till. The native vegetation is

mainly conifers and shrubs. Elevation is 1,000 to 2,000

feet. The average annual precipitation is about 70 inches,

the average annual air temperature is about 44 degrees F,

and the average frost-free period is about 120 days.

Typically, the surface is covered with a mat of needles

and twigs 6 inches thick. When mixed to a depth of 6

inches, the surface layer is grayish brown gravelly loam.

The subsoil is dark brown and yellowish brown very

gravelly loam 32 inches thick. Dense glacial till that crushes

to very gravelly sandy loam is at a depth of 38 inches. The

depth to dense glacial till ranges from 20 to 40 inches. The

dense glacial till is similar to a cemented pan. In some

areas the surface layer is gravelly silt loam. In other areas

the soil has less than 35 percent rock fragments in the

subsoil, is 40 to 60 inches deep to dense glacial till, or has

a less developed subsoil.

Included in this unit are small areas of Revel, Welcome,

Rinker, and Oakes soils, soils that are less than 20 inches

deep to dense glacial till, and Cupples soils that have

slopes of less than 30 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Cupples soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from December through

April. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are western

swordfern, deer fern, red huckleberry, western brackenfern,

longtube twinflower, and vine maple.

 On the basis of a 1 00-year site curve, the mean site

index for western hemlock is 143. On the basis of a 50-

year site curve, it is 102. The highest average growth rate

in unmanaged, even-aged stands of western hemlock is

224 cubic feet per acre per year, occurring at age 50. On

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

Douglas fir is estimated to be 154. On the basis of a 50-

year site curve, it is estimated to be 118. The highest

average growth rate in unmanaged, even-aged stands of

Douglas fir is about 163 cubic feet per acre per year,

occurring at age 60. Areas on ridgetops that are subject to

strong, persistent winds are less productive than the other

areas of this unit.

The main limitations affecting timber harvesting are

occasional snowpack, the slope, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and are subject to deep rutting during rainy

periods. Rock for road construction is not readily available.

Cut and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground can reduce the degree of

compaction and puddling. Steep yarding paths, skid trails,

and firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting

timber production. A low content of moisture in the surface

layer during the growing season hinders the survival of

planted and naturally established seedlings. The seedling

mortality rate is higher on ridgetops that are subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Douglas fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock occurs readily and reforestation by Douglas fir

and red alder occurs periodically. When openings are

made in the canopy, the uncontrolled invasion and growth

of competing plants can delay the establishment of

seedlings.
Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the dense glacial till, trees are occasionally subject to

windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass VIle.

38-Dekapen loam, 8 to 25 percent slopes. This

moderately deep, moderately well drained soil is on

mountain plateaus and back slopes. It formed in a mixture

of volcanic ash and loess over glacial till derived dominantly

from sandstone. The native vegetation is mainly conifers

and shrubs. Elevation is 1,600 to 2,200 feet. The average

annual precipitation is about 70 inches, the average annual

air temperature is about 44 degrees F, and the average

frost-free period is about 120 days.

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

leaves, and twigs 1 inch thick. When mixed to a depth of 8

inches, the surface layer is dark brown loam. The subsoil is

yellowish brown and dark yellowish brown loam 16 inches

thick. The next 7 inches is olive brown loam. Dense glacial

till that crushes to loam is at a depth of 31 inches. The

depth to dense glacial till ranges from 20 to 40 inches. The

dense glacial till is similar to a cemented pan. The content

of weathered rock fragments ranges from 35 to 60 percent

throughout this profile. In some areas the surface layer is

gravelly loam, gravelly silt loam, or silt loam. In other areas

the soil has 15 to 35 percent rock fragments in the subsoil,

is 40 to 60 inches deep to dense glacial till, or has a less

developed subsoil.

Included in this unit are small areas of Revel,

Welcome, Rinker, and Oakes soils, soils that are less than

20 inches deep to dense glacial till, and Dekapen soils

that have slopes of more than 25 percent or less than 8

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the

Dekapen soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 20 to 40 inches. Water is perched above the

dense glacial till from December through April. Runoff is

slow, and the hazard of water erosion is slight.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are western

swordfern, red huckleberry, western brackenfern, vine

maple, and longtube twinflower.

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

index for western hemlock is 149. On the basis of a 50-

year site curve, it is 106. The highest average growth

rate in unmanaged, even-aged stands of western hemlock

is 236 cubic feet per acre per year, occurring at age 50.

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

for Douglas fir is estimated to be 137. On the basis of a

50-year site curve, it is estimated to be 107. The highest

average growth rate in unmanaged, even-aged stands of

Douglas fir is about 140 cubic feet per acre per year,

occurring at age 70. Areas on ridgetops that are subject to

strong, persistent winds are less productive than the other

areas of this unit.

The main limitations affecting timber harvesting are the

muddiness caused by seasonal wetness and occasional

snowpack. During an average year, the snowpack limits the

use of equipment and restricts access from January

through March. Because most of the roots are concentrated

in the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes

tend to slump when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep skid trails and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production. The seedling

mortality rate is higher on ridgetops that are ,subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Douglas fir seedlings. When openings are made

in the canopy, the uncontrolled invasion and growth of

competing plants can delay the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the dense glacial till, trees are occasionally subject to

windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass IVe.

39-Deming gravelly silt loam, 5 to 30 percent slopes.

This very deep, well drained soil is on mountain back

slopes. It formed in a mixture of volcanic ash, slope

alluvium, and colluvium over unconsolidated glacial till

derived from sandstone, conglomerate, metasedimentary

rocks, and volcanic rocks. The native vegetation is mainly

conifers and shrubs. Elevation is
3,500 to 4,800 feet. The average annual precipitation is

about 90 inches, the average annual air temperature is

about 40 degrees F, and the average frost-free period is

about 90 days.

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

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

brown gravelly silt loam 2 inches thick. The upper 3 inches

of the subsoil is organic stained, reddish brown gravelly silt

loam. The lower 20 inches is dark brown and dark yellowish

brown very gravelly loam. The substratum to a depth of 60

inches is dark yellowish brown very gravelly loam. In some

areas the surface layer is gravelly loam, gravelly fine sandy

loam, or silt loam. In other areas the soil has dense glacial

till or bedrock at a depth of 40 to 60 inches, has 35 to 60

percent weathered rock fragments in the subsoil, has less

than 6 percent organic carbon in the upper part of the

subsoil, does not have a surface layer, or has a less

developed subsoil.

Included in this unit are small areas of Potchub, Saar,

Shuksan, and Kulshan soils, Rock outcrop, poorly drained

soils in depressions, soils that have serpentinitic

mineralogy, and Deming soils that have slopes of more than

30 percent or less than 5 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the Deming soil. Available

water capacity is high. The effective rooting depth is 60

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

slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent is mountain hemlock. The common

understory plants are red huckleberry, blueleaved

huckleberry, salmonberry, deer fern, western brackenfern,

and bunchberry dogwood.

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

index for western hemlock is estimated to be 93. On the

basis of a 50-year site curve, it is estimated to be 65. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 110 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal

wetness. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. Because most of the roots are concentrated

in the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft

when wet and are subject to deep rutting during rainy

periods. Rock for road construction is not readily

available. Cut and fill slopes tend to slump when wet.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction. Steep skid trails and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. If seed trees

are available, natural reforestation of cutover areas by

western hemlock, mountain hemlock, and Pacific silver fir

occurs periodically.

This map unit is in capability subclass VIe.

40-Deming gravelly silt loam, 30 to 60 percent

slopes. This very deep, well drained soil is on mountain

back slopes. It formed in a mixture of volcanic ash, slope

alluvium, and colluvium over unconsolidated glacial till

derived from sandstone, conglomerate, metasedimentary

rocks, and volcanic rocks. The native vegetation is mainly

conifers and shrubs. Elevation is 3,500 to 4,800 feet. The

average annual precipitation is about 90 inches, the

average annual air temperature is about 40 degrees F, and

the average frost-free period is about 90 days.

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

leaves, and twigs 4 inches thick. The surface layer is dark

brown gravelly silt loam 3 inches thick. The upper 5 inches

of the subsoil is organic stained, dark reddish brown

gravelly silt loam. The next 7 inches is strong brown very

gravelly loam. The lower 22 inches is dark brown very

gravelly sandy loam and dark yellowish brown extremely

gravelly sandy loam. The substratum to a depth of 60

inches is dark yellowish brown extremely gravelly loamy

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

gravelly fine sandy loam, or silt loam. In other areas the

soil has dense glacial till or bedrock at a depth of 40 to 60

inches, has 35 to 60 percent weathered rock fragments in

the subsoil, has less than 6 percent organic carbon in the

upper part of the subsoil, does not have a surface layer, or

has a less developed subsoil.

Included in this unit are small areas of Potchub,
Saar, Shuksan, and Kulshan soils, Rock outcrop, poorly

drained soils in depressions, soils that have serpentinitic

mineralogy, and Deming soils that have slopes of more

than 60 percent or less than 30 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the Deming soil. Available

water capacity is high. The effective rooting depth is 60

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

is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent is mountain hemlock. The common

understory plants are red huckleberry, blueleaved

huckleberry, salmonberry, deer fern, western brackenfern,

and bunchberry dogwood.

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

index for western hemlock is estimated to be 93. On the

basis of a 50-year site curve, it is estimated to be 65. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 110 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less

extensively. Because most of the roots are concentrated in

the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes

tend to slump when wet. Soil creep is common on this unit.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist. Carefully

laying out roads and cable yarding paths, properly timing

their use, and using cable systems that lift logs entirely off

the ground can reduce the degree of compaction. Steep

yarding paths, skid trails, and firebreaks are subject to

rilling and gullying unless adequate water bars are provided

or a protective plant cover is established. A moderate

reduction in productivity can be expected to result from

unmanaged fires in undisturbed areas.

Seedling mortality is the main concern affecting

timber production. A low soil temperature, deep

snowpack, and a short growing season hinder the survival

of planted and natural seedlings and delay their

establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting western hemlock or Pacific silver fir seedlings. If

seed trees are available, natural reforestation of cutover

areas by western hemlock, mountain hemlock, and Pacific

silver fir occurs periodically.

This map unit is in capability subclass VIIe.

41-Diobsud gravelly silt loam, 30 to 60 percent

slopes. This moderately deep, moderately well drained soil

is on mountain back slopes and ridges. It formed in a

mixture of volcanic ash and colluvium over glacial till

derived from phyllite. The native vegetation is mainly

conifers and shrubs. Elevation is 2,800 to 3,800 feet. The

average annual precipitation is about 90 inches, the

average annual air temperature is about 42 degrees F, and

the average frost-free period is about 95 days.

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

leaves, and twigs 7 inches thick. When mixed to a depth of

7 inches, the surface layer is dark brown gravelly silt loam.

The upper 9 inches of the subsoil is dark brown and strong

brown gravelly silt loam. The lower 4 inches is brown

gravelly silt loam. The substratum is olive gray gravelly

loam about 17 inches thick. Dense glacial till that crushes

to very gravelly loam is at a depth of 37 inches. The depth

to dense glacial till ranges from 20 to 40 inches. The dense

glacial till is similar to a cemented pan. In some areas the

surface layer is gravelly loam. In other areas the soil has a

very gravelly subsoil, has rock fragments of mixed

mineralogy, is 40 to 60 inches deep to dense glacial till or

bedrock, or has less than 6 percent organic carbon in the

upper part of the subsoil.

Included in this unit are small areas of Crinker,

Clendenen, and Hinker soils, Rock outcrop, and Diobsud

soils that have slopes of more than 60 percent or less than

30 percent. Included areas make up about 15 percent of

the total acreage.

Permeability is moderate in the upper part of the

Diobsud soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from November through

May. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among

the trees of limited extent are Alaska cedar, western

redcedar, and mountain hemlock. The common understory

plants are bunchberry dogwood, queencup
beadlily, tall blue huckleberry, red huckleberry, longtube

twinflower, and deer fern.

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

index for western hemlock is 105. On the basis of a 50-

year site curve, it is 75. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 151

cubic feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit. Estimates

of the site index or growth rate for Pacific silver fir have not

been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment and

restricts access from November through May. When timber

is harvested, the slope restricts the use of wheeled and

tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Rock for road construction is not

readily available. Extra rock is needed to maintain a stable,

uniform road surface. Cut and fill slopes tend to slump

when wet. Following road construction and clearcutting,

road failures and landslides are likely. Soil creep is common

on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and cable yarding paths, properly timing their use,

and using cable systems that lift logs entirely off the ground

can reduce the degree of compaction, puddling, and

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

subject to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are present, natural reforestation

of cutover areas by western hemlock, mountain hemlock,

and Pacific silver fir occurs periodically. Because the rooting

depth is restricted by the dense glacial till, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIe.

42-Edfro very gravelly silt loam, 8 to 30 percent

slopes. This shallow, moderately well drained soil is on

high mountain shoulder slopes and back slopes. It formed

in a mixture of volcanic ash, loess, and colluvium over

glacial till derived dominantly from dunite. The native

vegetation is mainly conifers and shrubs. Elevation is 2,400

to 3,600 feet. The average annual precipitation is about 95

inches, the average annual air temperature is about 41

degrees F, and the average frost-free period is about 95

days.

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

leaves, and twigs 7 inches thick. When mixed to a depth of

4 inches, the surface layer is dark brown very gravelly silt

loam. The upper 6 inches of the subsoil is organic stained,

reddish brown very gravelly silt loam. The lower 8 inches is

dark brown very gravelly loam. Dense glacial till that

crushes to very gravelly loamy sand is at a depth of 18

inches. The depth to dense glacial till ranges from 14 to 20

inches. The dense glacial till is similar to a cemented pan.

In some areas the surface layer is very gravelly loam or

gravelly silt loam. In other areas the soil has a less

developed subsoil or is 20 to 30 inches deep to dense

glacial till.

Included in this unit are small areas of Diobsud,

Crinker, Jackman, Klawatti, and Hinker soils, soils that are

shallow over bedrock or very shallow to dense glacial till,

Rock outcrop, and Edfro soils that have a stony surface or

have slopes of more than 30 percent or less than 8

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the Edfro

soil and very slow in the dense glacial till. Available water

capacity is low. The effective rooting depth is 14 to 20

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

slight. Water is perched above the dense glacial till from

December through April.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Alaska cedar, and mountain hemlock.

The common understory plants are tall blue huckleberry,

bunchberry dogwood, western brackenfern, deer fern, and

longtube twinflower. Vegetation is somewhat stunted and

sparse because of the toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.
The main limitation affecting timber harvesting is

snowpack. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. Because most of the roots are concentrated

in the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet. Steep skid trails and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established. A

moderate reduction in productivity can be expected to result

from unmanaged fires in undisturbed areas.

Seedling mortality and the hazard of windthrow are the

main concerns affecting the production of timber. A high

content of magnesium in relation to calcium, a high content

of iron, a low concentration of other important minerals, and

a low content of moisture in the surface layer during the

growing season hinder the survival of planted and naturally

established seedlings. A low soil temperature, deep

snowpack, and a short growing season also hinder the

survival of the seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock seedlings, which are adapted to the

toxicity of dunite soils. If seed trees are available, natural

reforestation of cutover areas by western hemlock,

mountain hemlock, Pacific silver fir, and Alaska cedar

occurs periodically. Trees grow poorly and lack vigor on

soils that are derived from dunite. Planting seedlings in the

organic layer improves growth and vigor. Because the

rooting depth is restricted by the dense glacial till, trees are

frequently subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass Vle.

43-Edfro very gravelly silt loam, 30 to 60 percent

slopes. This shallow, moderately well drained soil is on

high mountain shoulder slopes and back slopes. It formed

in a mixture of volcanic ash, loess, and colluvium over

glacial till derived dominantly from dunite. The native

vegetation is mainly conifers and shrubs. Elevation is

2,400 to 3,600 feet. The average annual precipitation is

about 95 inches, the average annual air temperature is

about 41 degrees F, and the average frost-free period is

about 95 days.

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

leaves, and twigs 4 inches thick. When mixed to a depth

of 3 inches, the surface layer is brown very gravelly silt

loam. The upper 4 inches of the subsoil is

organic stained, strong brown very gravelly silt loam. The

lower 12 inches is organic stained, yellowish red and dark

brown very gravelly silt loam. Dense glacial till that crushes

to very gravelly loam is at a depth of 19 inches. The depth

to dense glacial till ranges from 14 to 20 inches. The dense

glacial till is similar to a cemented pan. In some areas the

surface layer is very gravelly loam or gravelly silt loam. In

other areas the soil has a less developed subsoil or is 20

to 30 inches deep to dense glacial till.

Included in this unit are small areas of Diobsud, Crinker,

Jackman, Klawatti, and Hinker soils, soils that are shallow

over bedrock or very shallow to dense glacial till, Rock

outcrop, and Edfro soils that have slopes of more than 60

percent or less than 30 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the upper part of the Edfro

soil and very slow in the dense glacial till. Available water

capacity is low. The effective rooting depth is 14 to 20

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

is moderate. Water is perched above the dense glacial till

from December through April.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Alaska cedar, and mountain hemlock.

The common understory plants are tall blue huckleberry,

bunchberry dogwood, western brackenfern, deer fern, and

longtube twinflower. Vegetation is somewhat stunted and

sparse because of the toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less

extensively. Because most of the roots are concentrated in

the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet.
Following road construction and clearcutting, road failures

and landslides are likely. Soil creep is common on this

unit.

Steep yarding paths, skid trails, and firebreaks are

subject to rifling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground can reduce the degree of

compaction, puddling, and erosion. A moderate reduction in

productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A high content

of magnesium in relation to calcium, a high content of iron,

a low concentration of other important minerals, and a low

content of moisture in the surface layer during the growing

season hinder the survival of planted and naturally

established seedlings. A low soil temperature, deep

snowpack, and a short growing season also hinder the

survival of the seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock seedlings, which are adapted to the

toxicity of dunite soils. If seed trees are available, natural

reforestation of cutover areas by western hemlock,

mountain hemlock, Alaska cedar, and Pacific silver fir

occurs periodically. Trees grow poorly and lack vigor on

soils that are derived from dunite. Planting seedlings in the

organic layer improves growth and vigor. Because the

rooting depth is restricted by the dense glacial till, trees are

frequently subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIIe.

44-Edfro very stony silt loam, 30 to 60 percent

slopes. This shallow, moderately well drained soil is on

high mountain shoulder slopes and back slopes. It formed

in a mixture of volcanic ash, loess, and colluvium over

glacial till derived dominantly from dunite. The native

vegetation is mainly conifers and shrubs. Elevation is

2,400 to 3,600 feet. The average annual precipitation is

about 95 inches, the average annual air temperature is

about 41 degrees F, and the average frost-free period is

about 95 days.

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

leaves, and twigs 10 inches thick. When mixed to a depth

of 3 inches, the surface layer is dark brown very stony silt

loam. The upper 7 inches of the subsoil is organic stained,

yellowish red very gravelly silt loam. The lower 6 inches is

light olive brown and olive very

gravelly loam. Dense glacial till that crushes to very gravelly

loam is at a depth of 16 inches. The depth to dense glacial

till ranges from 14 to 20 inches. The dense glacial till is

similar to a cemented pan. In some areas the surface layer

is very gravelly silt loam or very gravelly loam. In other

areas the soil has a less developed subsoil or is 20 to 30

inches deep to dense glacial till.

Included in this unit are small areas of Diobsud,

Crinker, Jackman, Klawatti, and Hinker soils, soils that are

shallow over bedrock or very shallow to dense glacial till,

Rock outcrop, and Edfro soils that have slopes of more

than 60 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the upper part of the Edfro

soil and very slow in the dense glacial till. Available water

capacity is low. The effective rooting depth is 14 to 20

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

is moderate. Water is perched above the dense glacial till

from December through April.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Alaska cedar, and mountain hemlock.

The common understory plants are tall blue huckleberry,

bunchberry dogwood, western brackenfern, deer fern, and

longtube twinflower. Vegetation is somewhat stunted and

sparse because of the toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. The trees

can break if they are felled on stones on the surface, and

yarding operations can be hindered by the stones. During

an average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Rock for road construction is

not readily available. Cut and fill slopes tend to slump
when wet. Following road construction and clearcutting,

road failures and landslides are likely. Soil creep is

common on this unit.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground can reduce the degree of

compaction, puddling, and erosion. A moderate reduction in

productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A high content

of magnesium in relation to calcium, a high content of iron,

a low concentration of other important minerals, and a low

content of moisture in the surface layer during the growing

season hinder the survival of planted and naturally

established seedlings. A low soil temperature, deep

snowpack, and a short growing season also hinder the

survival of the seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock seedlings, which are adapted to the

toxicity of dunite soils. Because of the abundance of

surface stones, planting seedlings by hand is difficult. If

seed trees are available, natural reforestation of cutover

areas by western hemlock, mountain hemlock, Pacific silver

fir, and Alaska cedar occurs periodically. Trees grow poorly

and lack vigor on soils that are derived from dunite.

Planting seedlings in the organic layer improves growth

and vigor. Because the rooting depth is restricted by the

dense glacial till, trees are frequently subject to windthrow

when the soil is wet and winds are strong.

This map unit is in capability subclass Vls.

45-Edmonds-Woodlyn loamy, drained, 0 to 2

percent slopes. This map unit is on outwash terraces

and outwash plains. The native vegetation is mainly trees

and shrubs. Elevation is 50 to 300 feet. The average

annual precipitation is about 45 inches, the average

annual air temperature is about 50 degrees F, and the

average frost-free period is about 170 days.

This unit is 60 percent Edmonds soil and 25 percent

Woodlyn soil. The components of this unit occur as areas

so intricately intermingled that mapping them separately

was not practical at the selected scale of mapping.

Included in this unit are small areas of Tromp, Hale,

and Fishtrap soils, ponded areas in depressions, and

undrained Edmonds and Woodlyn soils. Included areas

make up about 15 percent of the total acreage.

The Edmonds soil is very deep and somewhat poorly

drained. It has been artificially drained. It formed in an

admixture of loess and volcanic ash over glacial outwash.

Typically, the surface layer is dark brown loam 11 inches

thick. The subsurface layer is dark grayish brown loam 7

inches thick. The subsoil is dark brown and yellowish red,

discontinuously cemented, mottled sand 19 inches thick.

The substratum to a depth of 60 inches is sand. It is

variegated but is dominantly dark grayish brown. The depth

to sand ranges from 14 to 20 inches. In some areas the

surface layer is sandy loam. In other areas the soil has

loamy glaciomarine or clayey marine deposits at a depth of

40 to 60 inches, has a substratum of sandy loam, or has 15

to 35 percent pebbles in the substratum.

Permeability is moderate in the upper part of the

Edmonds soil and very rapid in the substratum. Available

water capacity is low. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1.0 to

2.5 feet from November through April. Runoff usually is

very slow, and there is no hazard of erosion.

The Woodlyn soil is shallow and poorly drained. It has

been artificially drained. It formed in an admixture of loess

and volcanic ash over glacial outwash. Typically, the

surface layer is dark brown loam 9 inches thick. The

subsurface layer is dark grayish brown and grayish brown

loam 3 inches thick. The upper 5 inches of the subsoil is a

dark grayish brown, mottled, indurated hardpan that breaks

to loamy sand. The lower 8 inches is a dark brown, mottled,

weakly cemented hardpan that breaks to loamy sand. The

substratum to a depth of 60 inches is coarse sand. It is

variegated but is dominantly brown and olive gray. Depth to

the hardpan ranges from 10 to 14 inches. In some areas

the surface layer is sandy loam. In other areas the soil has

loamy glaciomarine or clayey marine deposits at a depth of

40 to 60 inches, has a substratum of sandy loam, has 15 to

35 percent pebbles in the substratum, or has the hardpan

at a depth of 14 to 24 inches.

Permeability is moderate in the upper part of the

Woodlyn soil, very slow in the hardpan, and very rapid in

the loose sand. Available water capacity is low. The

effective rooting depth is limited by a seasonal high water

table, which is at a depth of 1.0 to 2.5 feet from November

through April. Runoff is very slow, and there is no hazard of

erosion.

This unit is used mainly for hay and pasture or as

cropland. The included undrained Edmonds and

Woodlyn soils are used as woodland.

The main limitations in the areas used for hay and

pasture are the seasonal high water table, the low soil

fertility, and the low available water capacity. The dominant

method of drainage in the areas used for hay
and pasture is open ditches. In areas where the drainage

system is not maintained or in areas that do not have

drainage, the water table limits the use of this unit to

grasses and shallow-rooted legumes. Proper stocking

rates, pasture rotation, and restricted grazing during wet

periods help to keep the pasture in good condition.

Grazing when the soils are wet results in compaction of

the surface layer and poor tilth.

The main limitations in the areas used as cropland are

the seasonal high water table, the low soil fertility, and the

low available water capacity. The principal crops grown

are corn silage and small grain. Because of the inherent

low fertility, this unit requires proportionately more

fertilizer than most other soils in the survey area to

produce similar yields. The hardpan can be ripped and

shattered. Ripping and shattering increase the effective

rooting depth and improve internal drainage. Returning all

crop residue to the soil and including grasses, legumes, or

grass-legume mixtures in the cropping sequence help to

maintain fertility and tilth.

Tile drains and field ditches should be maintained for

adequate production on cropland and pasture. Maintaining

artificial drainage systems permits fieldwork to be

conducted earlier in the spring and increases the yields of

perennial crops. Most crops common to the survey area

can be grown if the drainage system is adequate. During

the growing season, the water table is artificially lowered to

a depth of about 3 to 5 feet. In summer, irrigation is

required for maximum production.

Red alder is the main woodland species in the

undrained areas of this unit. Among the trees of limited

extent are western hemlock, western redcedar, bigleaf

maple, paper birch, and black cottonwood. The common

understory plants are vine maple, salmonberry, red

huckleberry, western swordfern, and salal.

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

index for red alder is 90. The highest average growth

rate in unmanaged, even-aged stands of red alder is 101

cubic feet per acre per year, occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The seasonal

high water table limits the use of equipment to dry periods.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces

natural fertility and the available water capacity.

Unsurfaced roads are soft when wet and may be

impassable during rainy periods. Rock for road construction

is not readily available. Extra rock is needed to maintain a

stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soils are moist and a

moderate degree of puddling when the soils are wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment

can reduce the degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The seasonal high water table hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soils are wet and winds are strong.

The main limitation affecting homesite development

is the seasonal high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

The hardpan is rippable and, therefore, is not a serious

limitation for most engineering uses. In shallow excavations

special retainer walls may be needed to keep cutbanks

from caving. The main limitations on sites for septic tank

absorption fields are the seasonal high water table, the

cemented pan in the Woodlyn soil, and a poor filtering

capacity in the substratum. Installing the absorption field in

fill approved by the health district helps to compensate for

these limitations.

The Edmonds soil is in capability subclass Illw. The

Woodlyn soil is in capability subclass IVw.

46-Eliza silt loam, drained, 0 to 1 percent slopes.

This very deep, very poorly drained soil is on flood plains

and deltas. It has been artificially drained. It formed in

alluvium. The native vegetation is mainly trees and shrubs.

Elevation is at or near sea level to 20 feet above sea level.

The average annual precipitation is about 35 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 185 days.

Typically, the surface layer is very dark grayish brown

and dark grayish brown silt loam 11 inches thick. The

upper 4 inches of the underlying material also is very dark

grayish brown and dark grayish brown silt loam. The next 9

inches is gray and dark gray, mottled fine sandy loam. The

lower part to a depth of 60 inches is stratified dark gray,

gray, strong brown, and light gray, mottled silt loam and

fine sandy loam. In some areas the soil has sand at a

depth of 30 to 60 inches or is dominantly silt loam with 10

to 18 percent clay.

Included in this unit are small areas of Mt. Vernon
soils, bodies of water, undrained Eliza soils, and Eliza

soils that have slopes of 1 to 3 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the Eliza soil. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a depth

of 1.0 to 2.5 feet from November through April. Runoff is

very slow, and there is no hazard of erosion. This soil is

subject to frequent, brief periods of flooding from

November through April. It is subject to tidal inundation

unless protected.

This unit is used mainly for hay and pasture, as

cropland, or as a site for homes. The included

undrained Eliza soils are used as woodland.

The main limitations in the areas used as cropland are

the seasonal high water table, the hazard of flooding, and

the influence of salt. This soil is well suited to most crops

commonly grown in the survey area if adequate drainage

systems are maintained. The principal crops are peas,

sweet corn, beans, small grain, and corn silage. During the

growing season, the water table is artificially lowered to a

depth of about 3 to 5 feet. Installing tile drains no deeper

than 30 inches minimizes the effects of the salt. Tile drains

and field ditches should be maintained. They permit

fieldwork to be conducted earlier in the spring and increase

the yields of perennial crops. Using regulating structures in

open ditches as a means of subirrigation can reduce the

high acidity in the lower part of the underlying material. In

summer, irrigation is required for maximum production.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, black cottonwood, and Sitka spruce. The common

understory plants are willow, Douglas spirea, western

swordfern, western brackenfern, devilsclub, and Indian

plum.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitations affecting timber harvesting are the

hazard of flooding and the muddiness caused by seasonal

wetness. These limit the use of equipment to dry periods.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is needed to

maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate. The

seedling survival rate also may be low where flooding

occurs. Reforestation can be accomplished by planting red

alder or western redcedar seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the seasonal high water table and the

hazard of flooding. The wetness can be reduced by

building the house on a pad and by installing drainage tile

around footings if a suitable outlet is available. The main

limitations on sites for septic tank absorption fields are the

seasonal high water table and the hazard of flooding.

Installing absorption lines that are longer than normal and

installing flood-control structures help to overcome these

limitations.

This map unit is in capability subclass IIIw.

47-Eliza-Tacoma silt loams, 0 to 1 percent slopes.

This map unit is on flood plains, deltas, and tidal flats. The

native vegetation is mainly trees and shrubs. Elevation is

sea level to 20 feet above sea level. The average annual

precipitation is about 35 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 185 days.

This unit is 45 percent Eliza soil and 35 percent

Tacoma soil. The components of this unit occur as

areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Shalcar,

Snohomish, and Mr. Vernon soils and small bodies of

water. Included areas make up about 20 percent of the

total acreage.

The Eliza soil is very deep and very poorly drained. It

formed in alluvium. Typically, the surface layer is dark

grayish brown, mottled silt loam 4 inches thick. The upper 8

inches of the underlying material is olive gray, mottled silt

loam. The next 12 inches is dark gray, mottled silt loam.

The lower part to a depth of 60 inches is dark gray,

mottled, stratified sandy loam and loamy sand. Depth to the

acid substratum ranges from 30 to
60 inches. In some areas the soil has sand at a depth of

30 to 60 inches.

Permeability is moderate in the Eliza soil. Available water

capacity is high. The effective rooting depth is limited by a

seasonal high water table, which is at or near the surface

from November through April. Runoff is very slow, and there

is no hazard of erosion. This soil is subject to frequent, long

periods of flooding from December through April.

The Tacoma soil is very deep and very poorly drained. It

formed in alluvium. Typically, the surface layer is dark

grayish brown, mottled silt loam 11 inches thick. The upper

7 inches of the underlying material is dark grayish brown,

mottled silt loam. The next 30 inches is dark gray, mottled

silt loam. The lower part to a depth of 60 inches is dark

gray, mottled fine sandy loam. In some areas the surface

layer is very fine sandy loam. In other areas the soil has 18

to 35 percent clay in the upper part of the underlying

material or is 30 to 40 inches deep to fine sandy loam or

sand.

Permeability is moderately slow in the Tacoma soil.

Available water capacity is high. The effective rooting depth

is limited by a high water table, which is at or near the

surface from November through April during periods of high

tide. Runoff is very slow, but the hazard of water erosion is

severe because of the hazards of flooding and channeling.

This soil is subject to frequent, long periods of flooding from

December through April. It is subject to tidal inundation

unless protected. Channeling and deposition are common

along streambanks.

This unit is used as woodland or for wildlife habitat. Red

alder is the main woodland species. Among the trees of

limited extent are western redcedar, western hemlock, black

cottonwood, and Sitka spruce. The common understory

plants are willow, Douglas spirea, western swordfern,

western brackenfern, devilsclub, and Indian plum.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitations affecting timber harvesting are the

hazard of flooding and the muddiness caused by seasonal

wetness. These limit the use of equipment to dry periods.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is needed to

maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soils are moist and a

high degree of puddling when the soils are wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate. The

seedling survival rate also may be low where flooding

occurs. Reforestation can be accomplished by planting red

alder or western redcedar seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the high water table, trees are frequently subject to

windthrow when the soils are wet and winds are strong.

The Eliza and Tacoma soils are in capability

subclass VIw.

48-Everett gravelly sandy loam, hard substratum, 2

to 8 percent slopes. This deep, somewhat excessively

drained soil is on outwash terraces and moraines. It

formed in a mixture of volcanic ash and alluvium over

glacial outwash and glacial till. The native vegetation is

mainly conifers and shrubs. Elevation is 100 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 period is about 180 days.

Typically, the surface is covered with a mat of

undecomposed needles and twigs 2 inches thick. When

mixed to a depth of 6 inches, the surface layer is dark

yellowish brown gravelly sandy loam. The upper 7 inches

of the subsoil is dark brown gravelly sandy loam. The

lower 12 inches is strong brown very gravelly sandy loam.

The substratum is dark brown very gravelly loamy sand 16

inches thick. Dense glacial till that crushes to very gravelly

loamy sand is at a depth of 41 inches. The depth to very

gravelly loamy sand ranges from 14 to 30 inches. The

depth to dense glacial till or dense glaciomarine deposits

ranges from 40 to 60 inches. The dense glacial till is

similar to a cemented pan. In some areas the surface layer

is very gravelly sandy loam or very gravelly loam. In other

areas the soil has 15 to 35 percent rock fragments in the

subsoil, is very gravelly sandy loam in the upper part of

the substratum, or has dense glacial till or dense

glaciomarine deposits below a depth of 60 inches.

Included in this unit are small areas of Birchbay,

Clipper, Labounty, Sehome, and Squalicum soils and small

areas of Everett soils that have a stony surface or
have slopes of more than 8 percent or less than 2

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the Everett

soil, rapid and very rapid in the substratum, and very slow

in the dense glacial till. Available water capacity is low. The

effective rooting depth is limited by a seasonal high water

table, which is at a depth of 3.5 to 5.0 feet from December

through April. Runoff is slow, and the hazard of water

erosion is slight.

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

a site for homes.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, and grand fir. The common understory

plants are salal, creambush oceanspray, red huckleberry,

western swordfern, western brackenfern, common

snowberry, and Oregongrape.

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

index for Douglas fir is 138. On the basis of a 50-year site

curve, it is 106. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 142 cubic

feet per acre per year, occurring at age 70.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rounded pebbles and cobbles for road

construction are readily available.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of soil displacement when the soil is dry.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and displacement. A

moderate reduction in productivity can be expected to result

from unmanaged fires in undisturbed areas.

Seedling mortality and establishment are the main

concerns affecting timber production. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. A low content of moisture in the surface layer

during the growing season hinders the survival of planted

and naturally established seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be

reduced by building the house on a pad and by

installing drainage tile around footings if a suitable outlet is

available. The dense glacial till is rippable and, therefore,

is not a serious limitation for most engineering uses. In

shallow excavations special retainer walls may be needed

to keep cutbanks from caving.

The main limitations on sites for septic tank absorption

fields are a poor filtering capacity in the substratum and

the seasonal high water table. During the rainy season,

the effluent from onsite sewage disposal systems can

seep at points downslope. Installing the absorption field in

the loamy subsoil or in fill approved by the health district

helps to compensate for these limitations.

This map unit is in capability subclass Ille.

49-Everett very gravelly sandy loam, 8 to 15 percent

slopes. This very deep, somewhat excessively drained soil

is on outwash terraces and moraines. It formed in a

mixture of volcanic ash and alluvium over glacial outwash

and glacial till. The native vegetation is mainly conifer and

shrubs. Elevation is 100 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 period is about 180 days.

Typically, the surface is covered with a mat of

undecomposed needles, twigs, and rotting wood 4 inches

thick. When mixed to a depth of 6 inches, the surface layer

is dark brown very gravelly sandy loam. The subsoil is dark

brown very gravelly sandy loam 12 inches thick. The

substratum to a depth of 60 inches is variegated very

gravelly sand. The depth to very gravelly sand ranges from

14 to 24 inches. In some areas the surface layer is very

gravelly loam, gravelly sandy loam, or gravelly loam. In

other areas the soil has a substratum of very gravelly sand

at a depth of 24 to 36 inches, has a weakly cemented

hardpan at a depth of 40 to 60 inches, has 15 to 35

percent rock fragments in the subsoil, or has a substratum

of very gravelly sandy loam.

Included in this unit are small areas of Birchbay, Clipper,

and Squalicum soils and small areas of Everett soils that

have a stony surface or have slopes of more than 15

percent or less than 8 percent. Included areas make up

about 10 percent of the total acreage.

Permeability is rapid in the upper part of the Everett soil

and very rapid in the lower part. Available water capacity is

low. The effective rooting depth is 60 inches. Runoff is

slow, and the hazard of water erosion is slight.

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

hay and pasture, as a source of aggregate, and as a site

for homes.

Douglas fir is the main woodland species. Among the
trees of limited extent are red alder, western hemlock,

western redcedar, and bigleaf maple. The common

understory plants are salal, western brackenfern, red

huckleberry, rose, Oregongrape, and creambush

oceanspray.

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

index for Douglas fir is 138. On the basis of a 50-year site

curve, it is 106. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 142 cubic

feet per acre per year, occurring at age 70.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted

on this unit. Unsurfaced roads are soft when wet and are

subject to deep rutting during rainy periods. Logging roads

require suitable surfacing for year-round use. Rounded

pebbles and cobbles for road construction are readily

available.

Equipment and logs on the surface result in a

moderate degree of soil displacement when the soil is

dry. Carefully laying out roads and skid trails, properly

timing their use, and using low-pressure ground

equipment can reduce the degree of displacement. A

moderate reduction in productivity can be expected to

result from unmanaged fires in undisturbed areas.

Seedling mortality is the main concern affecting timber

production. Reforestation can be accomplished by planting

Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. A low content of moisture in the surface

layer during the growing season hinders the survival of

planted and naturally established seedlings. When

openings are made in the canopy, the uncontrolled invasion

and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

The main limitations in the areas used for hay and

pasture are the low available water capacity and the

slope.

If this unit is used for homesite development, the main

limitation is the slope. In shallow excavations special

retainer walls may be needed to keep cutbanks from

caving. The main limitation on sites for septic tank

absorption fields is a poor filtering capacity in the

substratum. Installing the absorption field in the loamy

subsoil or in fill approved by the health district helps to

compensate for this limitation. During the rainy season, the

effluent from onsite sewage disposal systems can seep at

points downslope. The slope affects the installation of

septic tank absorption fields. The absorption lines should

be installed on the contour.

This map unit is in capability subclass IVe.

50-Everett very gravelly sandy loam, 15 to 35

percent slopes. This very deep, somewhat excessively

drained soil is on outwash terraces and moraines. It

formed in a mixture of volcanic ash and alluvium over

glacial outwash and glacial till. The native vegetation is

mainly conifers and shrubs. Elevation is 100 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 period is about 180 days.

Typically, the surface is covered with a mat of

undecomposed needles, twigs, and rotting wood 4 inches

thick. When mixed to a depth of 6 inches, the surface layer

is dark brown very gravelly sandy loam. The subsoil is

dark brown very gravelly sandy loam 12 inches thick. The

substratum to a depth of 60 inches is variegated very

gravelly sand. The depth to very gravelly sand ranges from

14 to 24 inches. In some areas the surface layer is very

gravelly loam, gravelly sandy loam, or gravelly loam. In

other areas the soil has a substratum of very gravelly sand

at a depth of 24 to 36 inches, has a weakly cemented

hardpan at a depth of 40 to 60 inches, has 15 to 35

percent rock fragments in the subsoil, or has a substratum

of very gravelly sandy loam.

Included in this unit are small areas of Birchbay, Clipper,

and Squalicum soils and small areas of Everett soils that

have a stony surface or have slopes of more than 35

percent or less than 15 percent. Included areas make up

about 10 percent of the total acreage.

Permeability is rapid in the upper part of the Everett soil

and very rapid in the lower part. Available water capacity is

low. The effective rooting depth is 60 inches. Runoff is

slow, and the hazard of water erosion is slight.

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

hay and pasture and as a source of aggregate.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, and bigleaf maple. The common

understory plants are salal, western brackenfern, red

huckleberry, Oregongrape, and western swordfern.

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

index for Douglas fir is 138. On the basis of a 50-year site

curve, it is 106. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 142 cubic

feet per acre per year, occurring at age 70.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted on

this unit. Unsurfaced roads are soft when wet and are

subject to deep rutting during rainy periods. Logging roads

require suitable surfacing for year-round
use. Rounded pebbles and cobbles for road

construction are readily available. Cut and fill slopes

tend to ravel when dry.

Equipment and logs on the surface result in a moderate

degree of soil displacement when the soil is dry. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of displacement. Steep skid trails and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established. A

moderate reduction in productivity can be expected to

result from unmanaged fires in undisturbed areas.

Seedling mortality is the main concern affecting timber

production. Reforestation can be accomplished by planting.

Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. A low content of moisture in the surface

layer during the growing season hinders the survival of

planted and naturally established seedlings. When

openings are made in the canopy, the uncontrolled invasion

and growth of competing plants can delay the establishment

of seedlings. Competing vegetation can be controlled by

mechanical or chemical means.

The main limitations in the areas used for hay and

pasture are the low available water capacity, the hazard of

erosion, and the slope.

The main limitation affecting homesite development is

the slope. In shallow excavations special retainer walls

may be needed to keep cutbanks from caving. The main

limitations on sites for septic tank absorption fields are the

slope and a poor filtering capacity in the substratum.

Installing the absorption field in the loamy subsoil or in fill

approved by the health district helps to compensate for

these limitations. The slope affects the installation of

septic tank absorption fields. During the rainy season, the

effluent from onsite sewage disposal systems can seep at

points downslope.

This map unit is in capability subclass IVe.

51-Everett complex, 2 to 8 percent slopes. This map

unit is on outwash terraces and moraines. It formed in a

mixture of volcanic ash and alluvium over glacial outwash

and glacial till. The native vegetation is mainly conifers

and shrubs. Elevation is 100 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 period is about 180 days.

This unit is 50 percent Everett very gravelly sandy loam

and 35 percent Everett gravelly sandy loam. The

components of this unit occur as areas so intricately

intermingled that mapping them separately was not

practical at the selected scale of mapping.

Included in this unit are small areas of Birchbay,

Clipper, Labounty, and Squalicum soils and small areas of

Everett soils that have a stony surface, have a surface

layer of very gravelly sand, or have slopes of more than 8

percent or less than 2 percent. Also included are soils that

are similar to the Everett soil but have 15 to 35 percent

rock fragments in the subsoil or have a substratum of very

gravelly sandy loam. Included areas make up about 15

percent of the total acreage.

Everett very gravelly sandy loam is very deep and

somewhat excessively drained. Typically, the surface is

covered with a mat of undecomposed needles, twigs, and

rotting wood 4 inches thick. When mixed to a depth of 6

inches, the surface layer is dark brown very gravelly sandy

loam. The subsoil is dark brown very gravelly sandy loam

12 inches thick. The substratum to a depth of 60 inches is

variegated very gravelly sand. The depth to very gravelly

sand ranges from 14 to 24 inches.

Permeability is rapid in the upper part of this Everett

soil and very rapid in the lower part. Available water

capacity is low. The effective rooting depth is 60 inches.

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

Everett gravelly sandy loam is deep and well drained.

Typically, the surface is covered with a mat of

undecomposed needles and twigs 2 inches thick. When

mixed to a depth of 6 inches, the surface layer is dark

yellowish brown gravelly sandy loam. The upper 7 inches of

the subsoil is dark brown gravelly sandy loam. The lower

12 inches is strong brown very gravelly sandy loam. The

substratum is dark brown very gravelly loamy sand 16

inches thick. Dense glacial till that crushes to very gravelly

loamy sand is at a depth of 41 inches. The depth to very

gravelly loamy sand ranges from 14 to 30 inches. The

depth to dense glacial till or dense glaciomarine deposits

ranges from 40 to 60 inches. The dense glacial till is similar

to a cemented pan. In some areas the surface layer is very

gravelly sandy loam or very gravelly loam. In other areas

the soil has 15 to 35 percent rock fragments in the subsoil,

is very gravelly sandy loam in the upper part of the

substratum, or has weakly cemented glacial till or

glaciomarine deposits.

Permeability is moderate in the upper part of this Everett

soil, rapid in the next part, and very slow in the dense

glacial till. Available water capacity is low. The effective

rooting depth is limited by a seasonal high water table,

which is at a depth of 3.5 to 5.0 feet from December

through April. Runoff is slow, and the hazard of water

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

hay and pasture, as cropland, as a source of aggregate,

and as a site for homes.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, bigleaf maple, and grand fir. The

common understory plants are salal, western brackenfern,

red huckleberry, Oregongrape, and western swordfern.

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

index for Douglas fir is 138. On the basis of a 50-year site

curve, it is 106. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 142 cubic

feet per acre per year, occurring at age 70.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted

on this unit. Unsurfaced roads are soft when wet and are

subject to deep rutting during rainy periods. Logging roads

require suitable surfacing for year-round use. Rounded

pebbles and cobbles for road construction are readily

available.

Equipment and logs on the surface result in a

moderate degree of soil displacement when the soil is

dry. Carefully laying out roads and skid trails, properly

timing their use, and using low-pressure ground

equipment can reduce the degree of displacement. A

moderate reduction in productivity can be expected to

result from unmanaged fires in undisturbed areas.

Seedling mortality and establishment are the main

concerns affecting timber production. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by western hemlock occurs periodically. A low

content of moisture in the surface layer during the growing

season hinders the survival of planted and naturally

established seedlings. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

The main limitation in the areas used for hay and

pasture is the low available water capacity.

The main limitations in the areas used as cropland are

the low available water capacity and the very gravelly

surface layer. The principal crop is corn silage. The

pebbles in the surface layer make tillage difficult and can

cause equipment damage. In summer, irrigation is required

for maximum production.

If this unit is used for homesite development, the main

limitation is the seasonal high water table. The dense

glacial till is rippable and, therefore, is not a serious

limitation for most engineering uses. In shallow

excavations special retainer walls may be needed to

keep cutbanks from caving. The main limitation on sites

for septic tank absorption fields is a poor filtering capacity

in the substratum. The seasonal high water table in Everett

gravelly sandy loam also is a limitation. Installing the

absorption field in the loamy subsoil or in fill approved by

the health district helps to compensate for these limitations.

During the rainy season, the effluent from onsite sewage

disposal systems can seep at points downslope.

Everett very gravelly sandy loam is in capability

subclass IVe. Everett gravelly sandy loam is in

capability subclass Ille.

52-Everett-Urban land complex, 5 to 20 percent

slopes. This map unit is on outwash terraces. The native

vegetation is mainly conifers and shrubs. Elevation is 50 to

250 feet. The average annual precipitation is about 35

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

This unit is 50 percent Everett gravelly sandy loam and

30 percent Urban land. The components of this unit occur

as areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Chuckanut,

Squalicum, Sehome, Whatcom, and Labounty soils and

small areas of Everett soils that have slopes of more than

20 percent or less than 5 percent. Included areas make up

about 20 percent of the total acreage.

The Everett soil is deep and well drained. It formed

in a mixture of volcanic ash and alluvium over glacial

outwash and glacial till. When mixed to a depth of 6 inches,

the surface layer is dark yellowish brown gravelly sandy

loam. The upper 7 inches of the subsoil is dark brown

gravelly sandy loam. The lower 12 inches is strong brown

very gravelly sandy loam. The substratum is dark brown

very gravelly loamy sand 16 inches thick. Dense glacial till

that crushes to very gravelly loamy sand is at a depth of 41

inches. The depth to very gravelly loamy sand ranges from

14 to 30 inches. The depth to dense glacial till ranges from

40 to 60 inches. The dense galcial till is similar to a

cemented pan. In some areas the surface layer is very

gravelly sandy loam and the soil has 15 to 35 percent rock

fragments in the subsoil. In other areas the soil is very

gravelly sandy loam in the upper part of the substratum,

has dense glacial till below a depth of 60 inches, or has

weakly cemented dense glacial till.

Permeability is moderate in the upper part of the

Everett soil, rapid in the next part, and very slow in the

dense glacial till. Available water capacity is low. The

effective rooting depth is limited by a seasonal high water

table, which is at a depth of 3.5 to 5.0 feet from
December through April. Runoff is medium, and the

hazard of water erosion is moderate.

The Urban land consists of areas covered by streets,

buildings, parking lots, and other structures that so obscure

the soils that identification of the soil series is not feasible.

The Everett soil is used for lawns, gardens, parks, or

vacant lots. It is highly erodible during construction and on

cut and fill slopes.

If this unit is used for homesite development, the main

limitations are the slope and the seasonal high water

table. The wetness can be reduced by building the house

on a pad and by installing drainage tiles around footings if

a suitable outlet is available. The dense glacial till is

rippable and, therefore, is not a serious limitation for most

engineering uses. In shallow excavations special retainer

walls may be needed to keep cutbanks from caving.

The main limitations on sites for septic tank absorption

fields are a poor filtering capacity in the substratum and

the seasonal high water table. Installing the absorption

field in the loamy subsoil or in fill approved by the health

district helps to compensate for these limitations. During

the rainy season, the effluent from onsite sewage disposal

systems can seep at points downslope. The absorption

lines should be installed on the contour.

The Everett soil is in capability subclass Ille. The

Urban land is in capability subclass VIIIs.

53-Everson silt loam, drained, 0 to 2 percent slopes.

This very deep, poorly drained soil is in depressions on

outwash terraces. It has been artificially drained. It formed

in lacustrine deposits, alluvium, and glacial outwash with

an admixture of loess. The native vegetation is mainly trees

and shrubs. Elevation is 50 to 300 feet. The average

annual precipitation is about 45 inches, the average annual

air temperature is about 50 degrees F, and the average

frost-free period is about 170 days.

Typically, the surface layer is very dark grayish brown

silt loam 7 inches thick. The subsoil is grayish brown,

mottled silty clay 12 inches thick. The upper 21 inches of

the substratum is dark grayish brown and grayish brown

sand. The lower part to a depth of 60 inches is stratified

dark grayish brown very gravelly loamy sand and olive

brown gravelly sand. The depth to sand ranges from 14 to

30 inches. In some areas the soil has a substratum of

sandy loam or gravelly sandy loam or has more than 15

percent rock fragments in the upper part of the substratum.

Included in this unit are small areas of Hale,

Whitehorn, Labounty, and Edmonds soils, undrained

Everson soils, and soils that are similar to the Everson

soil but have 18 to 35 percent clay in the subsoil or have

a hardpan of dense glaciomarine drift at a depth of 40 to

60 inches. Included areas make up about 15 percent of

the total acreage.

Permeability is slow in the upper part of the Everson

soil and very rapid in the lower part. Available water

capacity is moderate. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1 to

3 feet from November through April. Runoff usually is very

slow, but the soil may be ponded during the winter. There

is no hazard of erosion.

This unit is used mainly for hay and pasture or as

cropland. It also is used as a site for homes. The

included undrained Everson soils are used as woodland.

The main limitations in the areas used for hay and

pasture are the seasonal high water table and the

moderate available water capacity. Proper stocking rates,

pasture rotation, and restricted grazing during wet periods

help to keep the pasture in good condition. Grazing when

the soil is wet results in compaction of the surface layer

and poor tilth. The water table limits the use of this unit to

grasses and shallow-rooted legumes unless a drainage

system is installed. The wetness limits the choice of plants

and the period of cutting or grazing and increases the risk

of winterkill.

The main limitations in the areas used as cropland are

the seasonal high water table and the moderate available

water capacity. The principal crops are small grain and corn

silage. This soil is well suited to most crops commonly

grown in the survey area if adequate drainage systems are

maintained. During the growing season, the water table is

artificially lowered to a depth of about 3 to 5 feet. Tile

drains and field ditches should be maintained. They permit

fieldwork to be conducted earlier in the spring and increase

the yields of perennial crops. In summer, irrigation is

required for maximum production.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, and bigleaf maple. The common understory

plants are willow, Douglas spirea, western swordfern,

western brackenfern, devilsclub, and Indian plum.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The high water

table limits the use of equipment to dry periods.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is
needed to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The seasonal high water table hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitation is the seasonal high water table. The wetness can

be reduced by building the house on a pad and by

installing drainage tile around footings if a suitable outlet is

available. The main limitations on sites for septic tank

absorption fields are the seasonal high water table and a

poor filtering capacity. Installing the absorption field in fill

approved by the health district helps to compensate for

these limitations.

This map unit is in capability subclass IIIw.

54-Fishtrap muck, drained, 0 to 2 percent slopes.

This very deep, very poorly drained soil is in depressions

on outwash terraces. It has been artificially drained. It

formed in herbaceous and woody organic deposits over

glaciofluvial deposits. The native vegetation is mainly

shrubs, forbs, and trees. Elevation is 50 to 300 feet. The

average annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 170 days.

Typically, the surface layer is very dark grayish brown

muck 7 inches thick. The upper 12 inches of the underlying

material is very dark brown muck. The lower part to a depth

of 60 inches is dark grayish brown and dark gray, mottled

sand. In some areas the surface layer is mucky silt loam. In

other areas the soil has hemic material in the surface

layer, is more than 51 inches deep to the lower part of the

underlying material, or is loamy in the lower part of the

underlying material.

Included in this unit are small areas of Hale and Tromp

soils, areas that are ponded, bodies of water,

undrained Fishtrap soils, and Fishtrap soils that have

slopes of more than 2 percent. Included areas make up

about 10 percent of the total acreage.

Permeability is moderate in the upper part of the

Fishtrap soil and very rapid in the lower part. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1.5

to 2.5 feet from October through May. Runoff usually is

very slow, but the soil may be ponded during the winter.

There is no hazard of erosion.

This unit is used mainly for hay and pasture or as

cropland. The included undrained Fishtrap soils are

used as woodland.

The main limitation in the areas used for hay and

pasture is the seasonal high water table. Proper stocking

rates, pasture rotation, and restricted grazing during wet

periods help to keep the pasture in good condition. The

wetness limits the choice of plants and the period of cutting

or grazing and increases the risk of winterkill. Grazing

when the soil is wet results in compaction of the surface

layer and poor tilth.

The main limitations in the areas used as cropland are

the seasonal high water table and the soil acidity. This soil

is well suited to most crops commonly grown in the survey

area if adequate drainage systems are maintained. The

principal crops are potatoes, blueberries, and corn silage.

Tile drains and field ditches should be maintained. They

permit fieldwork to be conducted earlier in the spring and

increase the yields of perennial crops. During the growing

season, the water table is artificially lowered to a depth of

about 3 to 5 feet. Subsidence is minimized if the water

table is maintained directly below the root zone during the

growing season and then allowed to return to the surface

during the winter. Using regulating structures in open

ditches as a means of subirrigation reduces the extent of

subsidence. In summer, irrigation is required for maximum

production.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, lodgepole pine, and Sitka spruce. The common

understory plants are willow, Douglas spirea, salmonberry,

stinging nettle, and sedges.

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

index for red alder is estimated to be 85. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 92 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The high water

table limits the use of equipment to dry periods.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is
needed to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The seasonal high water table hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

The main limitations affecting homesite development are

the seasonal high water table and the low strength. The

wetness can be reduced by building the house on a pad

and by installing drainage tile around footings if a suitable

outlet is available. If buildings are constructed on this soil,

the muck should be excavated or the buildings should be

constructed on piles anchored in the mineral soil. The

design of buildings and roads can offset the limited ability

of the soil to support a load. In shallow excavations special

retainer walls may be needed to keep cutbanks from

caving.

The main limitations on sites for septic tank absorption

fields are the seasonal high water table and a poor filtering

capacity. Installing the absorption field in fill approved by

the health district helps to compensate for these limitations.

This map unit is in capability subclass Ilw.

55-Gallup silt loam, 30 to 60 percent slopes. This

very deep, well drained soil is on mountain back slopes. It

formed in a mixture of volcanic ash, loess, colluvium, slope

alluvium, and unconsolidated glacial till derived from

sandstone and metasedimentary rocks. The native

vegetation is mainly conifers and shrubs. 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 period is about 90

days.

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

leaves, twigs, and rotting logs 12 inches thick. The surface

layer is dark brown silt loam 6 inches thick. The upper 8

inches of the subsoil is organic stained,

dark reddish brown and yellowish red gravelly loam and

gravelly silt loam. The lower 15 inches is dark brown and

dark yellowish brown gravelly loam. The substratum to a

depth of 60 inches is dark yellowish brown gravelly loam. In

some areas the surface layer is gravelly silt loam, loam, or

gravelly loam. In other areas the soil has dense glacial till

or bedrock at a depth of 40 to 60 inches, has a very

gravelly subsoil, has less than 6 percent organic carbon in

the upper part of the subsoil, or has a less developed

subsoil.

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

and Saar soils, Rock outcrop, soils that have serpentinitic

mineralogy, and Gallup soils that have slopes of more than

60 percent or less than 30 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the Gallup soil. Available

water capacity is high. The effective rooting depth is 60

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

is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. The

common understory plants are blueleaved huckleberry,

bunchberry dogwood, deer fern, western brackenfern, and

salmonberry.

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

index for western hemlock is 118. On the basis of a 50-year

site curve, it is 78. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 176

cubic feet per acre per year, occurring at age 50.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through April. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

These systems generally are used on this unit. Because

most of the roots are concentrated in the organic mat, loss

of this layer during logging greatly reduces natural fertility

and the available water capacity. Unsurfaced roads are soft

when wet and are subject to deep rutting during rainy

periods. Rock for road construction is not readily available.

Cut and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment
can reduce the degree of compaction and puddling.

Steep yarding paths, skid trails, and firebreaks are

subject to rifling and gullying unless adequate water

bars are provided or a protective plant cover is

established.

Seedling mortality and establishment are the main

concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock, Pacific silver

fir, or noble fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock,

mountain hemlock, and Pacific silver fir occurs periodically.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass VIIe.

56-Gallup silt loam, 60 to 80 percent slopes. This

very deep, well drained soil is on mountain back slopes. It

formed in a mixture of volcanic ash, loess, colluvium, slope

alluvium, and unconsolidated glacial till derived from

sandstone and metasedimentary rocks. The native

vegetation is mainly conifers and shrubs. 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 period is about 90

days.

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

leaves, twigs, and rotting logs 12 inches thick. The surface

layer is dark brown silt loam 3 inches thick. The upper 11

inches of the subsoil is organic stained, dark reddish brown

and yellowish red gravelly loam and gravelly silt loam. The

lower 25 inches is dark brown and dark yellowish brown

gravelly loam. The substratum to a depth of 60 inches is

dark yellowish brown gravelly loam. In some areas the

surface layer is gravelly silt loam, loam, or gravelly loam. In

other areas the soil has dense glacial till or bedrock at a

depth of 40 to 60 inches, has a very gravelly subsoil, has

less than 6 percent organic carbon in the upper part of the

subsoil, or has a less developed subsoil.

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

and Saar soils, Rock outcrop, soils that have serpentinitic

mineralogy, and Gallup soils that have slopes of less than

60 percent. Included areas make up about 15 percent of

the total acreage.

Permeability is moderate in the Gallup soil. Available

water capacity is high. The effective rooting depth is 60

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

severe.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. The

common understory plants are blueleaved huckleberry,

bunchberry dogwood, deer fern, western brackenfern, and

salmonberry.

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

index for western hemlock is 118. On the basis of a 50-

year site curve, it is 78. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 176

cubic feet per acre per year, occurring at age 50. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit. Estimates

of the site index or growth rate for Pacific silver fir have not

been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through April. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

These systems generally are used on this unit. Because

most of the roots are concentrated in the organic mat, loss

of this layer during logging greatly reduces natural fertility

and the available water capacity. Unsurfaced roads are soft

when wet and are subject to deep rutting during rainy

periods. Rock for road construction is not readily available.

Cut and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit. Locating roads

on midslopes requires extensive cutting and filling, which

remove land from production.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep yarding paths,

skid trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling mortality and establishment are the main

concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can

be accomplished by planting western
hemlock, Pacific silver fir, or noble fir seedlings. If seed

trees are available, natural reforestation of cutover areas by

western hemlock, mountain hemlock, and Pacific silver fir

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This map unit is in capability subclass VIle.

57-Gallup silt loam, cold, 30 to 60 percent slopes.

This very deep, well drained soil is on mountain back

slopes. It formed in a mixture of volcanic ash, loess,

colluvium, slope alluvium, and unconsolidated glacial till

derived from sandstone and metasedimentary rocks. The

native vegetation is mainly conifers and shrubs. Elevation

is 3,600 to 4,500 feet. The average annual precipitation is

about 90 inches, the average annual air temperature is

about 40 degrees F, and the average frost-free period is

about 90 days.

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

leaves, twigs, and rotting logs 12 inches thick. When

mixed to a depth of 6 inches, the surface layer is very dark

gray silt loam. The upper 6 inches of the subsoil is organic

stained, strong brown loam. The lower 17 inches is dark

brown and yellowish brown loam. The substratum to a

depth of 60 inches is dark grayish brown gravelly loam. In

some areas the surface layer is gravelly silt loam, loam, or

gravelly loam. In other areas the soil has dense glacial till

or bedrock at a depth of 40 to 60 inches, has a very

gravelly subsoil, has less than 6 percent organic carbon in

the upper part of the subsoil, or has a less developed

subsoil.

Included in this unit are small areas of Potchub,

Kulshan, and Shuksan soils, Rock outcrop, soils that

have serpentinitic mineralogy, and Gallup soils that have

slopes of more than 60 percent or less than 30 percent.

Included areas make up about 15 percent of the total

acreage.

Permeability is moderate in the Gallup soil. Available

water capacity is high. The effective rooting depth is 60

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

is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among

the trees of limited extent is mountain hemlock. The

common understory plants are red huckleberry, blueleaved

huckleberry, bunchberry dogwood, trailing blackberry, deer

fern, western brackenfern, and salmonberry:

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

index for western hemlock is 93. On the basis of a 50-

year site curve, it is 65. The highest average growth rate

in unmanaged, even-aged stands of western

hemlock is 110 cubic feet per acre per year, occurring at

age 60. Areas on ridgetops that are subject to .strong,

persistent winds are less productive than the other areas of

this unit. Estimates of: the site index or growth rate for

Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less

extensively. Because most of the roots are concentrated in

the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Carefully laying out

yarding paths, properly timing their use, and using cable

systems that lift logs entirely off the ground also reduce the

degree of compaction. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling mortality is the main concern affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. If seed trees

are available, natural reforestation of cutover areas by

western hemlock, mountain hemlock, and Pacific silver fir

occurs periodically.

This map unit is in capability subclass VIle.

58-Gallup silt loam, cold, 60 to 80 percent slopes.

This very deep, well drained soil is on mountain back

slopes. It formed in a mixture of volcanic ash, loess,

colluvium, slope alluvium, and unconsolidated glacial till

derived from sandstone and metasedimentary rocks.
The native vegetation is mainly conifers and shrubs.

Elevation is 3,600 to 4,500 feet. The average annual

precipitation is about 90 inches, the average annual air

temperature is about 40 degrees F, and the average frostfree period is about 90 days.

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

leaves, twigs, and rotting logs 12 inches thick. When mixed

to a depth of 6 inches, the surface layer is dark brown silt

loam. The upper 21 inches of the subsoil is organic stained,

dark reddish brown and yellowish red gravelly loam. The

lower 12 inches is dark brown and dark yellowish brown

gravelly loam. The substratum to a depth of 60 inches is

dark yellowish brown gravelly loam. In some areas the

surface layer is gravelly silt loam, loam, or gravelly loam. In

other areas the soil has dense glacial till or bedrock at a

depth of 40 to 60 inches, has a very gravelly subsoil, has

less than 6 percent organic carbon in the upper part of the

subsoil, or has a less developed subsoil.

Included in this unit are small areas of Potchub,

Kulshan, and Shuksan soils, Rock outcrop, soils that

have serpentinitic mineralogy, and Gallop soils that have

slopes of less than 60 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the Gallop soil. Available

water capacity is high. The effective rooting depth is 60

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

severe.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among

the trees of limited extent is mountain hemlock. The

common understory plants are red huckleberry, blueleaved

huckleberry, bunchberry dogwood, trailing blackberry, deer

fern, western brackenfern, and salmonberry.

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

index for western hemlock is 93. On the basis of a 50-

year site curve, it is 65. The highest average growth rate

in unmanaged, even-aged stands of western hemlock is

110 cubic feet per acre per year, occurring at age 60.

Areas on ridgetops that are subject to strong persistent

winds are less productive than the other areas of this unit.

Estimates of the site index or growth rate for Pacific silver

fir have not been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less

extensively. These systems generally are used on this unit.

Because most of the roots are concentrated in the organic

mat, loss of this layer

during logging greatly reduces natural fertility and the

available water capacity. Unsurfaced roads are soft when

wet and are subject to deep rutting during rainy periods.

Rock for road construction is not readily available. Cut and

fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit. Locating

roads on midslopes requires extensive cutting and filling,

which remove land from production.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction. Steep yarding paths, skid

trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling mortality is the main concern affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. Because of

the slope, planting seedlings is difficult. If seed trees are

available, natural reforestation of cutover areas by western

hemlock, mountain hemlock, and Pacific silver fir occurs

periodically.

This map unit is in capability subclass VIle.

59-Getchell loam, 3 to 30 percent slopes. This

moderately deep, moderately well drained soil is on

high mountain back slopes and plateaus. It formed in an

admixture of volcanic ash and colluvium over glacial till.

The native vegetation is mainly conifers and shrubs.

Elevation is 1,800 to 3,000 feet. The average annual

precipitation is about 75 inches, the average annual air

temperature is about 42 degrees F, and the average frostfree period is about 105 days.

Typically, the surface is covered with a mat of needles

and twigs 5 inches thick. When mixed to a depth of 4

inches, the surface layer is dark brown loam. The upper 8

inches of the subsoil is dark brown sandy loam. The lower

24 inches is brown sandy loam. Dense glacial till that

crushes to sandy loam is at a depth of 36 inches. The

depth to dense glacial till ranges from 200 to 40 inches. The

dense glacial till is similar to a cemented pan. In some

areas the surface layer is silt loam or gravelly loam. In

other areas the soil has a gravelly subsoil, has 15 to 35

percent phyllite rock fragments in
the subsoil and in the dense glacial till, is 40 to 60 inches

deep to dense glacial till or sandstone, has more than 6

percent organic carbon in the lower part of the surface

layer and upper part of the subsoil, or has a less developed

subsoil.

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

Oso, and Revel soils, soils that are less than 20 inches

deep to dense glacial till, Rock outcrop, poorly drained

soils in depressions, and Getchell soils that have slopes of

more than 30 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the upper part of the

Getchell soil and very slow in the dense glacial till.

Available water capacity is high. The effective rooting

depth is 20 to 40 inches. Water is perched above the

dense glacial till from November through April. Runoff is

slow, and the hazard of water erosion is slight.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Douglas fir, and western redcedar. The

common understory plants are red huckleberry, deer fern,

western brackenfern, devilsclub, ladyfern, and bunchberry

dogwood.

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

index for western hemlock is 129. On the basis of a 50-year

site curve, it is 91. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 198

cubic feet per acre per year, occurring at age 50. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal wetness.

During an average year, the snowpack limits the use of

equipment and restricts access from December through

April. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep skid trails and

firebreaks are subject to rilling and gullying unless adequate

water bars are provided or a protective plant cover is.

established.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting

timber production. A low soil temperature, deep

snowpack, and a short growing season hinder the survival

of planted and natural seedlings and delay their

establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. When openings are

made in the canopy, the uncontrolled invasion and growth

of competing plants can delay the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the dense glacial till, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

This map unit is in capability subclass Vle.

60-Getchell loam, 30 to 60 percent slopes. This

moderately deep, moderately well drained soil is on

high mountain back slopes and plateaus. It formed in an

admixture of volcanic ash and colluvium over glacial till.

The native vegetation is mainly conifers and shrubs.

Elevation is 1,800 to 3,000 feet. The average annual

precipitation is about 75 inches, the average annual air

temperature is about 42 degrees F, and the average frostfree period is about 105 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. The surface layer is dark reddish

brown loam 2 inches thick. The upper 10 inches of the

subsoil is dark yellowish brown loam. The lower 22 inches

is dark yellowish brown gravelly loam. Dense glacial till

that crushes to gravelly loam is at a depth of 34 inches.

The depth to dense glacial till ranges from 20 to 40 inches.

The dense glacial till is similar to a cemented pan. In some

areas the surface layer is silt loam or gravelly loam. In

other areas the soil has a nongravelly subsoil, has 15 to 35

percent phyllite rock fragments in the subsoil and in the

dense glacial till, is 40 to 60 inches deep to dense glacial

till or sandstone, has more than 6 percent organic carbon

in the upper part of the subsoil, or has a less developed

subsoil.

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

Oso, and Revel soils, soils that are less than 20 inches

deep to dense glacial till, Rock outcrop, poorly drained soils

in depressions, and Getchell soils that have slopes of more

than 60 percent or less than 30 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Getchell soil and very slow in the dense glacial till.

Available water capacity is high. The effective rooting

depth is 20 to 40 inches. Water is perched above the
dense glacial till from November through April. Runoff is

medium, and the hazard of water erosion is severe.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Douglas fir, and western redcedar. The

common understory plants are red huckleberry, deer fern,

western brackenfern, devilsclub, ladyfern, and bunchberry

dogwood.

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

index for western hemlock is 129. On the basis of a 50-year

site curve, it is 91. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 198

cubic feet per acre per year, occurring at age 50. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment and

restricts access from December through April. When timber

is harvested, the slope restricts the use of wheeled and

tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Rock for road construction is

not readily available. Cut and fill slopes tend to slump when

wet. Following road construction and clearcutting, road

failures and landslides are likely. Soil creep is common on

this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and cable yarding paths, properly timing their use, and

using cable systems that lift logs entirely off the ground can

reduce the degree of compaction and puddling. Steep

yarding paths, skid trails, and firebreaks are subject to rilling

and gullying unless adequate water bars are provided or a

protective plant cover is established.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are subject

to strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Pacific silver fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and

Pacific silver fir occurs periodically. When openings are

made in the canopy, the uncontrolled invasion and growth

of competing plants can delay the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the dense glacial till, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

This map unit is in capability subclass VIle.

61-Hale silt loam, 0 to 2 percent slopes. This very

deep, somewhat poorly drained soil is on outwash terraces.

It formed in an admixture of loess and volcanic ash over

glacial outwash. The native vegetation is mainly trees and

shrubs. Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

Typically, when mixed to a depth of 8 inches, the

surface layer is dark brown silt loam. The subsoil is light

olive brown, mottled loam 8 inches thick. The substratum to

a depth of 60 inches is mottled sand. It is variegated but is

dominantly grayish brown. The depth to sand or loamy

sand ranges from 15 to 30 inches. In some areas the

surface layer is loam. In other areas the soil has a

substratum of sandy loam, gravelly sandy loam, gravelly

sand, or very gravelly sand.

Included in this unit are small areas of Whitehorn,

Everson, Edmonds, Labounty, Shalcar, Fishtrap, and Yelm

soils, drained Hale soils, and soils that are similar to the

Hale soil but have 18 to 35 percent clay in the subsoil or

have a hardpan of dense glaciomarine drift at a depth of 40

to 60 inches. Included areas make up about 20 percent of

the total acreage.

Permeability is moderate in the upper part of the Hale

soil and very rapid in the substratum. Available water

capacity is moderate. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1 to

2 feet from November through April. Runoff usually is very

slow, but the soil may be ponded during the winter. There

is no hazard of erosion.

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

hay and pasture.

Red alder and Douglas fir are the main woodland

species. Among the trees of limited extent are western

hemlock and western redcedar. The common understory

plants are salmonberry, western

brackenfern, red huckleberry, western swordfern, trailing

blackberry, and sweetscented bedstraw.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,
occurring at age 40. On the basis of a 100-year site curve,

the mean site index for Douglas fir is estimated to be 120.

On the basis of a 50-year site curve, it is estimated to be

90. The highest average growth rate in unmanaged, evenaged stands of Douglas fir is about 115 cubic feet per acre

per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and may be impassable during

rainy periods. Rock for road construction is not readily

available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling.

Seedling establishment is the main concern affecting

timber production. The seasonal high water table hinders

root respiration and thus results in a low seedling survival

rate. Reforestation can be accomplished by planting red

alder, Douglas fir, or western redcedar seedlings. If seed

trees are available, natural reforestation of cutover areas by

red alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the seasonal high water table, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

The main limitation in the areas used for hay and

pasture is the seasonal high water table. The water table

limits the use of this unit to grasses unless a drainage

system is installed. Grazing when the soil is wet results in

compaction of the surface layer and poor tilth.

This map unit is in capability subclass IVw.

62-Hale silt loam, drained, 0 to 2 percent slopes.

This very deep, somewhat poorly drained soil is on outwash

terraces. It has been artificially drained. It formed in an

admixture of loess and volcanic ash over glacial outwash.

The native vegetation is mainly trees and shrubs. Elevation

is 50 to 300 feet. The average annual precipitation is about

45 inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface layer is very dark grayish brown

silt loam 10 inches thick. The subsoil is about 16

inches of mottled olive gray, grayish brown, dark brown,

and strong brown silt loam and loam. The upper 12 inches

of the substratum is dark grayish brown loamy fine sand.

The lower part to a depth of 60 inches is sand. It is

variegated but is dominantly dark grayish brown. The depth

to sand or loamy sand ranges from 15 to 30 inches. In

some areas the surface layer is loam. In other areas the

soil has a substratum of sandy loam, gravelly sandy loam,

gravelly sand, or very gravelly sand.

Included in this unit are small areas of Birchbay, Lynden,

Kickerville, Whitehorn, Everson, Labounty, Fishtrap,

Edmonds, and Laxton soils, undrained Hale soils, and soils

that are similar to the Hale soil but have 18 to 35 percent

clay in the subsoil or have a hardpan of dense glaciomarine

drift at a depth of 40 to 60 inches. Included areas make up

about 20 percent of the total acreage.

Permeability is moderate in the upper part of the Hale

soil and very rapid in the substratum. Available water

capacity is moderate. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1 to

4 feet from November through April. Runoff usually is very

slow, but the soil may be ponded during the winter. There

is no hazard of erosion.

This unit is used mainly for hay and pasture or as

cropland. It also is used as woodland and as a site for

homes.

The main limitations in the areas used for hay and

pasture are the seasonal high water table and the moderate

available water capacity. Proper stocking rates, pasture

rotation, and restricted grazing during wet periods help to

keep the pasture in good condition. Grazing when the soil is

wet results in compaction of the surface layer and poor tilth.

The water table limits the use of this unit to grasses unless

a drainage system is installed. The wetness limits the

choice of plants and the period of cutting or grazing and

increases the risk of winterkill.

The main limitations in the areas used as cropland are

the seasonal high water table and the moderate available

water capacity. The principal crops are small grain and corn

silage. This unit is well suited to most crops commonly

grown in the survey area if adequate drainage systems are

maintained. During the growing season, the water table is

artificially lowered to a depth of about 3 to 5 feet. Tile

drains and field ditches should be maintained. They permit

fieldwork to be conducted earlier in the spring and increase

the yields of perennial crops. In summer, irrigation is

required for maximum production.

Red alder and Douglas fir are the main woodland

species. Among the trees of limited extent are western

hemlock and western redcedar. The common
understory plants are salmonberry, western brackenfern,

red huckleberry, western swordfern, trailing blackberry, and

sweetscented bedstraw.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40. On the basis of a 100-year site curve,

the mean site index for Douglas fir is estimated to be 120.

On the basis of a 50-year site curve, it is estimated to be

90. The highest average growth rate in unmanaged, evenaged stands of Douglas fir is about 115 cubic feet per acre

per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet causes

excessive rutting. Using low-pressure ground equipment

can minimize damage to the soil. Unsurfaced roads are soft

when wet and may be impassable during rainy periods.

Rock for road construction is not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. The seasonal high water table hinders

root respiration and thus results in a low seedling survival

rate. Reforestation can be accomplished by planting red

alder, Douglas fir, or western redcedar seedlings. If seed

trees are available, natural reforestation of cutover areas

by red alder occurs readily. When openings are made in

the canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the seasonal high water table, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is

available. In shallow excavations special retainer walls

may be needed to keep cutbanks from caving. The main

limitations on sites for septic tank absorption fields are the

seasonal high water table and a poor filtering capacity in

the substratum. Installing absorption lines that are longer

than normal helps to overcome these limitations.

This map unit is in capability subclass Ilw.

63-Hallenton silt loam, 0 to 1 percent slopes. This

very deep, very poorly drained soil is in depressions on

glaciomarine drift plains. It formed in a mixture of loess,

volcanic ash, and glaciomarine drift. The native vegetation

is mainly forbs, shrubs, and trees. Elevation is 200 to 300

feet. The average annual precipitation is about 40 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free period is about 170 days.

Typically, the surface layer is grayish brown silt loam 11

inches thick. The subsoil is light brownish gray, mottled silt

loam 8 inches thick. The substratum to a depth of 60

inches is olive, mottled silt loam. In some areas the surface

layer is loam. In other areas the substratum has 10 to 18

percent clay, has lenses of sandy material, or has 0 to 10

percent cobbles.

Included in this unit are small areas of Whatcom,

Labounty, and Shalcar soils and bodies of water.

Included areas make up about 15 percent of the total

acreage.

Permeability is slow in the Hallenton soil. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at or

above the surface from November through August. Runoff

is very slow, and there is no hazard of erosion.

This unit is used for wildlife habitat. Common plants are

Douglas spirea, cattail, skunkcabbage, and salmonberry.

This map unit is in capability subclass VIIw.

64-Hannegan very gravelly loam, 15 to 40 percent

slopes. This shallow, well drained soil is on mountain

shoulder slopes and ridges. It formed in a mixture of

volcanic ash, loess, and colluvium derived dominantly from

phyllite and sandstone. The native vegetation is mainly

conifers and shrubs. Elevation is 3,800 to 4,200 feet. The

average annual precipitation is about 100 inches, the

average annual air temperature is about 40 degrees F, and

the average frost-free period is about 90 days.

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

leaves, and twigs 5 inches thick. When mixed to a depth of

5 inches, the surface layer is dark brown very gravelly

loam. The subsoil is dark yellowish brown very cobbly loam

12 inches thick. Phyllite is at a depth of about 17 inches.

The depth to phyllite ranges from 14 to 20 inches. In some

areas the surface layer is very cobbly loam or very gravelly

silt loam. In other areas the soil has less than 35 percent

hard pebbles in the subsoil or is 20 to 30 inches deep to

phyllite.

Included in this unit are small areas of Clendenen and

Saar soils, Rock outcrop, and Hannegan soils that have

slopes of more than 40 percent or less than 15 percent.

Included areas make up about 20 percent of
the total acreage. The percentage varies from one area to

another.

Permeability is moderate in the Hannegan soil. Available

water capacity is low. The effective rooting depth is 14 to

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

is slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent is mountain hemlock. The common

understory plants are tall blue huckleberry, salmonberry,

bunchberry dogwood, deer fern, and western brackenfern.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitation affecting timber harvesting is

snowpack. During an average year, the snowpack limits

the use of equipment and restricts access from November

through May. Because most of the roots are concentrated

in the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Phyllite, a poor-quality

rock for road construction, is readily available. Extra rock is

needed to maintain a stable, uniform road surface. Cut and

fill slopes tend to slump when wet. Steep skid trails and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low content of

moisture in the surface layer during the growing season

hinders the survival of planted and naturally established

seedlings. A low soil temperature, deep snowpack, and a

short growing season also hinder the survival of the

seedlings and delay their establishment. The seedling

mortality rate is higher on ridgetops that are subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Pacific silver fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. Because

the rooting depth is restricted by the bedrock, trees are

frequently subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass Vle.

65-Hartnit silt loam, cold, 5 to 30 percent slopes.

This moderately deep, well drained soil is on mountain back

slopes and plateaus. It formed in a mixture of volcanic ash,

glacial till, and colluvium derived from sandstone and

metasedimentary rocks. The native vegetation is mainly

conifers and shrubs. Elevation is 2,600 to 3,600 feet. The

average annual precipitation is about 85 inches, the

average annual air temperature is about 42 degrees F, and

the average frost-free period is about 100 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. When mixed to a depth of 4

inches, the surface layer is dark brown silt loam. The upper

15 inches of the subsoil is gravelly silt loam. The lower 6

inches is dark yellowish brown very gravelly loam. Bedrock

is at a depth of about 25 inches. The depth to bedrock

ranges from 20 to 40 inches. In some areas the surface

layer is loam, gravelly loam, or gravelly silt loam. In other

areas the soil is very gravelly in the upper part of the

subsoil, is 40 to 60 inches deep over bedrock, or is more

developed in the upper part of the subsoil.

Included in this unit are small areas of Klawatti,

Getchell, Kindy, and Gallup soils, Rock outcrop, poorly

drained mineral and organic soils in depressions, soils that

are less than 20 inches deep over bedrock, and Hartnit

soils that have slopes of more than 30 percent or less

than 5 percent. Included areas make up about 15 percent

of the total acreage.

Permeability is moderate in the Hartnit soil. Available

water capacity is moderate. The effective rooting depth is

20 to 40 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, western redcedar, Douglas fir, and

mountain hemlock. The common understory plants are red

huckleberry, blueleaved huckleberry, bunchberry dogwood,

and longtube twinflower.

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

index for western hemlock is estimated to be 105. On the

basis of a 50-year site curve, it is estimated to be 75. The

highest average growth rate in unmanaged,

even-aged stands of western hemlock is about 151 cubic

feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal

wetness. During an average year, the snowpack limits the

use of equipment and restricts access from November

through April. The use of wheeled and
tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Rock for

road construction is readily available. Cut and fill slopes

tend to slump when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling. Steep skid trails and firebreaks

are subject to rilling and gullying unless adequate water

bars are provided or a protective plant cover is established.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. If seed trees

are available, natural reforestation of cutover areas by

western hemlock and Pacific silver fir occurs periodically.

When openings are made in the canopy, the uncontrolled

invasion and

growth of competing plants can delay the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the bedrock, trees are occasionally subject

to windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass VIe.

66-Hartnit silt loam, cold, 30 to 60 percent slopes.

This moderately deep, well drained soil is on mountain

back slopes and plateaus. It formed in a mixture of

volcanic ash, loess, glacial till, and colluvium derived from

sandstone and metasedimentary rocks. The native

vegetation is mainly conifers and shrubs. Elevation is

2,600 to 3,600 feet. The average annual precipitation is

about 85 inches, the average annual air temperature is

about 42 degrees F, and the average frost-free period is

about 100 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. When mixed to a depth of 4

inches, the surface layer is dark brown silt loam. The

upper 15 inches of the subsoil is dark brown and brown

gravelly loam and gravelly silt loam. The

lower 6 inches is dark yellowish brown very gravelly loam.

Bedrock is at a depth of about 25 inches. The depth to

bedrock ranges from 20 to 40 inches. In some areas the

surface layer is loam, gravelly loam, or gravelly silt loam. In

other areas the soil is very gravelly in the upper part of the

subsoil, is 40 to 60 inches deep over bedrock, or is more

developed in the upper part of the subsoil.

Included in this unit are small areas of Klawatti,

Getchell, Kindy, and Gallup soils, Rock outcrop, poorly

drained mineral and organic soils in depressions, soils that

are less than 20 inches deep over bedrock, and Hartnit

soils that have slopes of more than 60 percent or less

than 30 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the Hartnit soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the

hazard of water erosion is moderate.

This unit is used as woodland (fig. 4). Western

hemlock is the main woodland species. Among the

trees of limited extent are Pacific silver fir, western

redcedar, and Douglas fir. The common understory

plants are red huckleberry, blueleaved huckleberry,

bunchberry dogwood, and longtube twinflower.

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

index. for western hemlock is estimated to be 105. On the

basis of a 50-year site curve, it is estimated to be 75. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 151 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through April. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces

natural fertility and the available water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is readily available. Cut and fill slopes tend to

slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and cable yarding paths, properly timing their

use, and using cable systems that lift logs entirely off
Figure 4.-A clear-cut area of Hartnit silt loam, cold, 30 to 60 percent slopes, in the foreground.

the ground can reduce the degree of compaction and

puddling. Steep yarding paths, skid trails, and firebreaks

are subject to rilling and gullying unless adequate water

bars are provided or a protective plant cover is established.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. If seed trees

are available, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. When openings are

made in the canopy, the uncontrolled invasion and growth

of competing plants can delay the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the bedrock, trees are occasionally subject

to windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass VIle.

67-Hartnit-Gallup-Rock outcrop complex, 50 to 80

percent slopes. This map unit is on mountain back slopes.

The native vegetation is mainly conifers and shrubs.

Elevation is 2,600 to 3,600 feet. The average
annual precipitation is about 90 inches, the average

annual air temperature is about 42 degrees F, and the

average frost-free period is about 95 days.

This unit is 40 percent Hartnit silt loam, 30 percent

Gallup silt loam, and 15 percent Rock outcrop. The

components of this unit occur as areas so intricately

intermingled that mapping them separately was not

practical at the selected scale of mapping.

Included in this unit are small areas of Saar soils, soils

that are less than 20 inches deep over bedrock, stony

areas, and Hartnit and Gallup soils that have slopes of

more than 80 percent or less than 50 percent. Included

areas make up about 15 percent of the total acreage.

The Hartnit soil is moderately deep and well drained. It

formed in a mixture of volcanic ash, colluvium, and glacial

till derived from sandstone and metasedimentary rocks.

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

leaves, and twigs 6 inches thick. When mixed to a depth of

8 inches, the surface layer is dark brown and strong brown

silt loam. The upper 11 inches of the subsoil is dark

yellowish brown gravelly silt loam. The lower 12 inches is

yellowish brown gravelly silt loam. Sandstone is at a depth

of about 31 inches. The depth to bedrock ranges from 20 to

40 inches. In some areas the soil has a surface layer of

loam or gravelly silt loam, has bedrock at a depth of 40 to

60 inches, has less than 6 percent organic carbon in the

upper part of the subsoil, or has a less developed subsoil.

Permeability is moderate in the Hartnit soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is rapid, and the hazard of water

erosion is severe.

The Gallup soil is very deep and well drained. It formed

in a mixture of volcanic ash, loess, colluvium, slope

alluvium, and unconsolidated glacial till derived from

sandstone and metasedimentary rocks. Typically, the

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

6 inches thick. When mixed to a depth of 8 inches, the

surface layer is dark brown and strong brown silt loam. The

subsoil is yellowish brown gravelly silt loam 16 inches thick.

The substratum to a depth of 60 inches is light olive brown

gravelly silt loam. In some areas the surface layer is

gravelly silt loam, loam, or gravelly loam. In other areas the

soil has dense glacial till or bedrock at a depth of 40 to 60

inches, has a very gravelly subsoil, has less than 6 percent

organic carbon in the upper part of the subsoil or lower part

of the surface layer, or has a less developed subsoil.

Permeability is moderate in the Gallup soil. Available

water capacity is high. The effective rooting depth is 60

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

severe.

Typically, the Rock outcrop is sandstone. It is hard

and generally unweathered. It occurs as steep cliffs and

irregular formations.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among

the trees of limited extent are western redcedar and

Douglas fir. The common understory plants are red

huckleberry, blueleaved huckleberry, bunchberry dogwood,

trailing blackberry, and deer fern.

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

index for western hemlock on the Hartnit soil is estimated

to be 105. On the basis of a 50-year site curve, it is

estimated to be 75. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is about

151 cubic feet per acre per year, occurring at age 60. On

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

western hemlock on the Gallup soil is estimated to be 118.

On the basis of a 50-year site curve, it is estimated to be

78. The highest average growth rate in unmanaged, evenaged stands of western hemlock is about 176 cubic feet per

acre per year, occurring at age 50. Yields are reduced by

the extent of the Rock outcrop. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack, the Rock outcrop, the slope, and the hazard of

erosion. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. The pattern of the Rock outcrop on the

landscape results in a discontinuous slope, which hinders

the use of cable yarding systems. These systems generally

are used on this unit. The trees can break if they are felled

on the Rock outcrop. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Sandstone,

a poor-quality rock for road construction, is readily

available. Cut and fill slopes tend to slump when wet.

Following road construction and clearcutting, road failures

and landslides are likely. Locating roads on midslopes

requires extensive cutting and filling, which remove land

from production. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soils are moist and a high

degree of puddling when the soils are wet. Carefully laying

out roads and cable yarding paths, properly timing their

use, and using cable systems that lift logs entirely off the

ground can reduce the degree of compaction, puddling, and

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

subject to rilling
and gullying unless adequate water bars are provided or

a protective plant cover is established.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock, noble fir, or Pacific silver fir seedlings.

The slope makes the planting of seedlings difficult. If seed

trees are available, natural reforestation of cutover areas by

western hemlock and Pacific silver fir occurs periodically.

The Rock outcrop prevents the even distribution of

reforestation. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

delay the establishment of seedlings. Competing vegetation

can be controlled by mechanical or chemical means.

Because the rooting depth is restricted by the bedrock,

trees on the Hartnit soil are occasionally subject to

windthrow when the soils are wet and winds are strong.

The Hartnit and Gallup soils are in capability

subclass Vlle. The Rock outcrop is in capability

subclass Vllls.

68-Heisler very gravelly silt loam, 8 to 30 percent

slopes. This very deep, well drained soil is on mountain

back slopes. It formed in a mixture of volcanic ash and

loess over colluvium derived from glacial till high in content

of phyllite. The native vegetation is mainly conifers and

shrubs. Elevation is 400 to 1,200 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 170 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. When mixed to a depth of 6

inches, the surface layer is dark brown very gravelly silt

loam. The upper 18 inches of the subsoil is yellowish

brown very gravelly silt loam. The lower 8 inches is light

olive brown extremely channery loam. The substratum to a

depth of 60 inches is pale olive extremely channery sandy

loam. In some areas the surface layer is very gravelly

loam, gravelly loam, or gravelly silt loam. In other areas

the soil has less than 35 percent rock fragments in the

subsoil and substratum or is not dominated by phyllite.

Included in this unit are small areas of Vanzandt,

Squires, and Barneston soils and small areas of Heisler

soils that have slopes of more than 30 percent or less than

8 percent. Included areas make up about 15 percent of

the total acreage.

Permeability is moderate in the Heisler soil. Available

water capacity also is moderate. The effective rooting

depth is 60 inches. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are red

alder, western hemlock, western redcedar, and bigleaf

maple. The common understory plants are western

swordfern, Oregongrape, red huckleberry, deer fern, Pacific

trillium, bedstraw, and salal.

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

index for Douglas fir is 165. On the basis of a 50-year site

curve, it is 127. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 176 cubic

feet per acre per year, occurring at age 60.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted on

this unit. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet. Steep skid trails and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Seedling establishment is the main concern affecting

timber production. A low content of moisture in the surface

layer during the growing season hinders the survival of

planted and naturally established seedlings. Reforestation

can be accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by Douglas fir and western hemlock occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This map unit is in capability subclass IVe.

69-Heisler very gravelly silt loam, 30 to 60 percent

slopes. This very deep, well drained soil is on mountain

back slopes. It formed in a mixture of volcanic ash and

loess over colluvium derived from glacial till high in content

of phyllite. The native vegetation is mainly conifers and

shrubs. Elevation is 400 to 1,200 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 170 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. When mixed to a depth of 6

inches, the surface layer is dark brown very
gravelly silt loam. The upper 18 inches of the subsoil is

yellowish brown very gravelly silt loam. The lower 8 inches

is light olive brown extremely channery loam. The

substratum to a depth of 60 inches is pale olive extremely

channery sandy loam. In some areas the surface layer is

very gravelly loam, gravelly loam, or gravelly silt loam. In

other areas the soil has less than 35 percent rock

fragments in the subsoil and substratum or is not

dominated by phyllite.

Included in this unit are small areas of Vanzandt,

Squires, and Barneston soils and small areas of Heisler

soils that have slopes of more than 60 percent or less than

30 percent. Included areas make up about 15 percent of

the total acreage.

Permeability is moderate in the Heisler soil. Available

water capacity also is moderate. The effective rooting depth

is 60 inches. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

red alder, western hemlock, western redcedar, and bigleaf

maple. The common understory plants are western

swordfern, Oregongrape, red huckleberry, deer fern, Pacific

trillium, bedstraw, and salal.

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

index for Douglas fir is 165. On the basis of a 50-year site

curve, it is 127. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 176 cubic

feet per acre per year, occurring at age 60.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is

harvested, the slope restricts the use of wheeled and

tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces

natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling establishment is the main concern affecting

timber production. A low content of moisture in the surface

layer during the growing season hinders the

survival of planted and naturally established seedlings.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily

and reforestation by Douglas fir and western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

This map unit is in capability subclass VIIe.

70-Hinker very channery silt loam, 5 to 30

percent slopes. This moderately deep, well drained soil is

on high mountain shoulder slopes. It formed in a mixture of

volcanic ash, loess, and colluvium derived dominantly from

phyllite. The native vegetation is mainly conifers and

shrubs. Elevation is 3,500 to 4,200 feet. The average

annual precipitation is about 95 inches, the average annual

air temperature is about 41 degrees F, and the average

frost-free period is about 95 days.

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

leaves, and twigs 6 inches thick. The surface layer is

pinkish gray very channery silt loam 6 inches thick. The

upper 5 inches of the subsoil is organic stained, dark

brown very channery silt loam. The lower 10 inches is dark

brown very channery loam. Phyllite is at a depth of about

21 inches. The depth to phyllite ranges from 20 to 40

inches. In some areas the surface layer is very channery

loam, very gravelly silt loam, or very gravelly loam. In other

areas the soil has less than 6 percent organic carbon in

the lower part of the subsoil, is 40 to 60 inches deep to

phyllite, or has a less developed subsoil.

Included in this unit are small areas of Diobsud and

Saar soils, soils that are 14 to 20 inches deep to phyllite,

Rock outcrop, and Hinker soils that have slopes of more

than 30 percent or less than 5 percent. Included areas

make up about 20 percent of the total acreage.

Permeability is moderate in the Hinker soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are Alaska cedar and mountain

hemlock. The common understory plants are tall blue

huckleberry, bunchberry dogwood, deer fern, western

brackenfern, and salmonberry..

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

index for western hemlock is estimated to be 91. On the

basis of a 50-year site curve, it is estimated to be 65. The

highest average growth rate in unmanaged, even-
aged stands of western hemlock is about 107 cubic feet per

acre per year, occurring at age 60. Areas on ridgetops that

are subject to strong, persistent winds are less productive

than the other areas of this unit. Estimates of the site index

or growth rate for Pacific silver fir have not been made.

The main limitation affecting timber harvesting is

snowpack. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. Because most of the roots are concentrated in

the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Phyllite, a poorquality rock for road construction, is readily available. Cut

and fill slopes tend to slump when wet. Steep skid trails and

firebreaks are subject to rilling and gullying unless adequate

water bars are provided or a protective plant cover is

established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low content of

moisture in the surface layer during the growing season

hinders the survival of planted and naturally established

seedlings. A low soil temperature, deep snowpack, and a

short growing season also hinder the survival of the

seedlings and delay their establishment. The seedling

mortality rate is higher on ridgetops that are subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Pacific silver fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. Because

the rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIe.

71-Hinker very channery silt loam, 30 to 60 percent

slopes. This moderately deep, well drained soil is on high

mountain shoulder slopes. It formed in a mixture of volcanic

ash, loess, and colluvium derived dominantly from phyllite.

The native vegetation is mainly conifers and shrubs.

Elevation is 3,500 to 4,200 feet. The average annual

precipitation is about 95 inches, the average annual air

temperature is about 41 degrees F, and the average frostfree period is about 95 days.

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

leaves, and twigs 6 inches thick. The surface layer is

pinkish gray very channery silt loam 6 inches thick. The

upper 5 inches of the subsoil is organic stained, dark

brown very channery silt loam. The lower 10 inches is dark

brown very channery loam and very

channery silt loam. Phyllite is at a depth of about 21

inches. The depth to phyllite ranges from 20 to 40 inches.

In some areas the surface layer is very channery loam,

very gravelly silt loam, or very gravelly loam. In other areas

the soil has less than 6 percent organic carbon in the

lower part of the subsoil, is 40 to 60 inches deep to

phyllite, or has a less developed subsoil.

Included in this unit are small areas of Diobsud and

Saar soils, soils that are 14 to 20 inches deep to phyllite,

Rock outcrop, and Hinker soils that have slopes of more

than 60 percent or less than 30 percent. Included areas

make up about 20 percent of the total acreage.

Permeability is moderate in the Hinker soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is medium, and the hazard of

water erosion is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are Alaska cedar and mountain

hemlock. The common understory plants are tall blue

huckleberry, bunchberry dogwood, deer fern, western

brackenfern, and salmonberry.

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

index for western hemlock is estimated to be 91. On the

basis of a 50-year site curve, it is estimated to be 65. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 107 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Phyllite, a poor-quality rock for

road construction, is readily available. Cut and fill slopes

tend to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of
erosion. Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low content of

moisture in the surface layer during the growing season

hinders the survival of planted and naturally established

seedlings. A low soil temperature, deep snowpack, and a

short growing season also hinder the survival of the

seedlings and delay their establishment. The seedling

mortality rate is higher on ridgetops that are subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Pacific silver fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. Because

the rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIIe.

72-Histosols, ponded, 0 to 1 percent slopes. These

very deep, very poorly drained soils are in backswamps on

flood plains and on the edge of bodies of water. They

formed in mixed organic material

consisting of mosses, forbs, and shrubs over mineral

material. The native vegetation is mainly shrubs, forbs,

and trees. 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 period is about 170 days.

No single profile is representative of this map unit. In

one of the more commonly observed ones, however, the

surface layer is dark brown and dark grayish brown muck

about 28 inches thick. The underlying material to a depth of

70 inches is gray silt loam. The depth to mineral material

ranges from 16 to 50 inches. After rubbing, the fiber

content ranges from 5 to 25 percent. Reaction ranges from

extremely acid to medium acid in

the organic material and from strongly acid to neutral in

the mineral material. In some areas the surface layer is

mucky silt loam or hemic material.

Included in this unit are small areas of ponded

Bellingham or Pangborn soils and areas where

Histosols have been partially drained. Included areas

make up about 10 percent of the total acreage.

Permeability is moderate or moderately slow in the

Histosols. Available water capacity is high. The effective

rooting depth is limited by a seasonal high water table,

which is at or above the surface from November through

August. Runoff is ponded, and there is no hazard of

erosion.

This unit is used for wildlife habitat.

This map unit is in capability subclass Vw.

73-Hovde silt loam, 0 to 2 percent slopes. This very

deep, poorly drained soil is on marine terraces. It formed in

marine sediments and gravelly coastal beach deposits. The

native vegetation is mainly trees and shrubs. Elevation is 5

to 20 feet. The average annual precipitation is about 35

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface is covered with a mat of leaves

and twigs 1 inch thick. The surface layer is very dark

grayish brown, mottled silt loam 9 inches thick. The

underlying material to a depth of 60 inches is very dark

grayish brown and dark grayish brown very gravelly sand or

very gravelly coarse sand. In some areas the surface layer

is loam. In other areas the soil has less than 35 percent

rock fragments in the substratum or has a surface layer

that is 12 to 16 inches thick.

Included in this unit are small areas of Eliza and

Tacoma soils and bodies of water. Included areas make up

about 10 percent of the total acreage.

Permeability is very rapid in the Hovde soil. Available

water capacity is low. The effective rooting depth is limited

by a high water table, which is at or near the surface from

November through April during periods of high tide. Runoff

usually is very slow, but the soil may be ponded in the

winter. There is no hazard of erosion. This soil is subject to

frequent, brief periods of flooding from November through

April. It is subject to tidal inundation unless protected.

Channeling and deposition are common along

streambanks.

This unit is used mainly as woodland or for wildlife

habitat. Red alder is the main woodland species. Among

the trees of limited extent are western redcedar and black

cottonwood. The common understory plants are

salmonberry, Douglas spirea, rose, stinging nettle, and

sedges.

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

index for red alder is estimated to be 85. The highest

average growth rate in unmanaged, even-aged stands of red

alder is about 92 cubic feet per acre per year, occurring

at age 40.

The main limitations affecting: timber harvesting are the

muddiness caused by seasonal wetness and the hazard of

flooding. Unsurfaced roads are soft when wet and may be

impassable during rainy periods. Rounded pebbles for road

construction are readily available. Extra rock is needed to

maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying
out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table and the flooding hinder

root respiration and thus result in a low seedling survival

rate. Reforestation can be accomplished by planting red

alder or western redcedar seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the high water table, trees are frequently subject to

windthrow when the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the high water table and the hazard of

flooding. The wetness can be reduced by building the

house on a pad and by installing drainage tile around

footings if a suitable outlet is available. In shallow

excavations special retainer walls may be needed to keep

cutbanks from caving. The main limitations on sites for

septic tank absorption fields are the hazard of flooding, the

seasonal wetness, and a poor filtering capacity. The

seasonal high water table increases the likelihood that the

absorption field will fail. Installing the absorption field in fill

approved by the health district helps to compensate for

these limitations.

This map unit is in capability subclass VIw.

74-Hozomeen gravelly loam, 20 to 45 percent slopes.

This shallow, moderately well drained soil is on mountain

back slopes. It formed in a mixture of volcanic ash, loess,

and colluvium over glacial till. The native vegetation is

mainly conifers and shrubs. Elevation is 1,800 to 3,200

feet. The average annual precipitation is about 85 inches,

the average annual air temperature is about 43 degrees F,

and the average frost-free period is about 100 days.

Typically, the surface is covered with a mat of needles

and twigs 6 inches thick. When mixed to a depth of 4

inches, the surface layer is dark reddish brown gravelly

loam. The upper 9 inches of the subsoil is dark reddish

brown and dark brown very gravelly loam. The lower 5

inches is strong brown very gravelly loam. Dense glacial till

that crushes to gravelly loam is at a depth of 18 inches.

The depth to dense glacial till ranges from 14 to 20 inches.

The dense glacial till is similar to a cemented pan. In some

areas the surface layer is gravelly silt loam or loam. In

other areas the soil has less than 35 percent rock

fragments in the subsoil

or has dominantly phyllite, serpentine, or dunite rock

fragments in the subsoil and in the dense glacial till.

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

Klawatti, Springsteen, and Clendenen soils, Rock outcrop,

and Hozomeen soils that have slopes of more than 45

percent or less than 20 percent. Included areas make up

about 20 percent of the total acreage.

Permeability is moderate in the upper part of the

Hozomeen soil and very slow in the dense glacial till.

Available water capacity is low. The effective rooting depth

is 14 to 20 inches. Water is perched above the dense

glacial till from November through April. Runoff is medium,

and the hazard of water erosion is moderate.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir and western redcedar. The common

understory plants are red huckleberry, Oregongrape, salal,

bunchberry dogwood, western brackenfern, and trailing

blackberry.

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

index for western hemlock is estimated to be 114. On the

basis of a 50-year site curve, it is estimated to be 80. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 168 cubic feet per

acre per year, occurring at age 50.

The main limitations affecting timber harvesting are

snowpack, the slope, and the muddiness caused by

seasonal wetness. During an average year, the snowpack

limits the use of equipment and restricts access from

December through April. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and may be impassable during rainy periods.

Rock for road construction is not readily available. Cut and

fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment or

cable yarding systems can reduce the degree of

compaction and puddling. Steep skid trails and firebreaks

are subject to rilling and gullying unless adequate water

bars are provided or a protective plant cover is

established.

Plant competition and the hazard of windthrow are the

main concerns affecting timber production. A low content

of moisture in the surface layer during the growing season

hinders the survival of planted and naturally established

seedlings. A low soil temperature,
deep snowpack, and a short growing season also hinder

the survival of the seedlings and delay their establishment.

The seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock seedlings. If seed trees are available,

natural reforestation of cutover areas by western hemlock

and Pacific silver fir occurs periodically. When openings are

made in the canopy, the uncontrolled invasion and growth

of competing plants can delay the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the dense glacial till, trees are frequently

subject to windthrow when the soil is wet and winds are

strong.

This map unit is in capability subclass Vle.

75-Hydraquents, tidal, 0 to 1 percent slopes. These

very deep, poorly drained soils are on tidal flats. They

formed in alluvium. The native vegetation is mainly

saltgrass. Elevation is sea level. The average annual

precipitation is about 35 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

No single profile is representative of this map unit. In

one of the more commonly observed ones, however, the

surface layer is gray and olive gray fine sandy loam about 6

inches thick. The underlying material to a depth of 60

inches is gray and olive gray stratified silt loam, loam, and

fine sandy loam. The content of clay ranges from 10 to 25

percent by weighted average. In some areas the soil has

strata of sand or silty clay loam.

Included in this unit are small areas of water and

Psammaquents. Included areas make up about 10

percent of the total acreage.

Permeability is moderate in the Hydraquents. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at or above the

surface during periods of high tide throughout the year.

These soils are subject to frequent, long periods of flooding

during high tides throughout the year.

This unit is used for wildlife habitat or recreation.

This map unit is in capability subclass Vllw.

76-Jackman gravelly silt loam, 30 to 60 percent

slopes. This very deep, well drained soil is on mountain

back slopes. It formed in a mixture of volcanic ash,

colluvium, slope alluvium, and glacial drift derived

dominantly from dunite. The native vegetation is mainly

conifers and shrubs. Elevation is 2,200 to 3,600 feet. The

average annual precipitation is about 85 inches, the

average annual air temperature is about 42 degrees

F, and the average frost-free period is about 100 days.

Typically, the surface is covered with a mat of needles

and twigs 2 inches thick. When mixed to a depth of 9

inches, the surface layer is dark yellowish brown gravelly

silt loam. The upper 6 inches of the subsoil is yellowish

brown very gravelly silt loam. The lower 17 inches is strong

brown very gravelly silt loam and yellowish brown very

gravelly loam. The substratum to a depth of 60 inches is

dark brown very gravelly loam. In some areas the surface

layer is gravelly loam. In other areas the soil has a

substratum of very gravelly loamy sand or has a more

developed subsoil.

Included in this unit are small areas of Twinsi and

Klawatti soils, Rock outcrop, and Jackman soils that

have slopes of more than 60 percent or less than 30

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the Jackman soil. Available

water capacity is high. The effective rooting depth is 60

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

is moderate.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir and Alaska cedar. The common

understory plants are tall blue huckleberry, deer fern,

western brackenfern, and western rattlesnake plantain.

Vegetation is somewhat stunted and sparse because of the

toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment and

restricts access from November through May. When timber

is harvested, the slope restricts the use of wheeled and

tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Rock for road construction is

not readily available. Cut and fill slopes tend to slump when

wet. Following road construction and clearcutting, road

failures and landslides are likely. Soil creep is common on

this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying
out roads and cable yarding paths, properly timing their

use, and using cable systems that lift logs entirely off the

ground can reduce the degree of compaction and puddling.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of other

important minerals, and a low content of moisture in the

surface layer during the growing season hinder the survival

of planted and naturally established seedlings. A low soil

temperature, deep snowpack, and a short growing season

also hinder the survival of the seedlings and delay their

establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting western hemlock, Pacific silver fir, or Alaska

cedar seedlings, which are adapted to the toxicity of dunite

soils. If seed trees are available, natural reforestation of

cutover areas by western hemlock, Pacific silver fir, and

Alaska cedar occurs periodically. Trees grow poorly and

lack vigor on soils that are derived from dunite.

This map unit is in capability subclass VIIe.

77-Jorgensen gravelly silt loam, 3 to 15 percent

slopes. This very deep, somewhat excessively drained soil

is on outwash terraces. It formed in a mixture of volcanic

ash, loess, and glacial outwash derived dominantly from

dunite. The native vegetation is mainly conifers and shrubs.

Elevation is 2,200 to 3,100 feet. The average annual

precipitation is about 95 inches, the average annual air

temperature is about 42 degrees F, and the average frostfree period is about 95 days.

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

leaves, twigs, and rotting logs 18 inches thick. When mixed

to a depth of 5 inches, the surface layer is brown gravelly

silt loam. The upper 3 inches of the subsoil is organic

stained, dark brown gravelly loam. The lower 11 inches is

dark yellowish brown very gravelly sandy loam. The

substratum to a depth of 60 inches is olive brown

extremely gravelly loamy sand. The depth to extremely

gravelly sand or loamy sand ranges from 10 to 25 inches.

In some areas the surface layer is gravelly loam. In other

areas the soil has less than 6 percent organic carbon in

the upper part of the subsoil.

Included in this unit are small areas of Jackman, Twinsi,

and Klawatti soils and small areas of Jorgensen soils that

have slopes of more than 15 percent or less

than 3 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderately rapid in the upper part of the

Jorgensen soil and very rapid in the substratum. Available

water capacity is moderate. The effective rooting depth is

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

is slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are mountain hemlock and Alaska

cedar. The common understory plants are tall blue

huckleberry, western brackenfern, deer fern, and western

rattlesnake plantain. Vegetation is somewhat stunted and

sparse because of the toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 84. On the

basis of a 50-year site curve, it is estimated to be 60. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 95 cubic feet per acre

per year, occurring at age 60. Estimates of the site index

or growth rate for Pacific silver fir have not been made.

The main limitation affecting timber harvesting is

snowpack. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. Because most of the roots are concentrated

in the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Rounded pebbles and

cobbles for road construction are readily available. Cut and

fill slopes tend to ravel when dry.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling. Steep skid

trails and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of

other important minerals, and a low content of moisture in

the surface layer during the growing season hinder the

survival of planted and naturally established seedlings. A

low soil temperature, deep snowpack, and a short growing

season also hinder the survival of the seedlings and delay

their establishment. Reforestation can be accomplished by
planting western hemlock, Pacific silver fir, or Alaska

cedar seedlings, which are adapted to the toxicity of

dunite soils. If seed trees are available, natural

reforestation of cutover areas by western hemlock,

Pacific silver fir, and Alaska cedar occurs periodically.

Trees grow poorly and lack vigor on soils that are derived

from dunite. Planting seedlings in the organic layer

improves growth and vigor.

This map unit is in capability subclass Vle.

78-Jug very gravelly loam, 3 to 15 percent slopes.

This very deep, somewhat excessively drained soil is on

outwash terraces. It formed in a mixture of volcanic ash

and glacial outwash over glacial outwash. The native

vegetation is mainly conifers and shrubs. Elevation is

1,000 to 2,000 feet. The average annual precipitation is

about 75 inches, the average annual air temperature is

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

about 115 days.

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

leaves, and twigs 5 inches thick. When mixed to a depth of

6 inches, the surface layer is dark brown very gravelly

loam. The upper 3 inches of the subsoil is strong brown

very gravelly loam. The lower 16 inches is yellowish brown

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

inches is olive brown very gravelly loamy sand. The depth

to very gravelly loamy sand ranges from 13 to 25 inches. In

some areas the surface layer is very gravelly sandy loam.

In other areas the soil has a substratum of very gravelly

sandy loam, has a subsoil of very gravelly loamy sand, or

has less than 35 percent rock fragments in the subsoil and

substratum.

Included in this unit are small areas of Oakes, Cupples,

Sandun, and Sorensen soils and small areas of Jug soils

that have slopes of more than 15 percent or less than 3

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderately rapid in the upper part of the

Jug soil and very rapid in the substratum. Available water

capacity is moderate. The effective rooting depth is 60

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

slight.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar and red alder.

The common understory plants are red huckleberry,

Oregongrape, salal, princes pine, western swordfern, deer

fern, ladyfern, vine maple, and western brackenfern.

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

index is 156 for western hemlock and 169 for Douglas fir.

On the basis of a 50-year site curve, it is 111 for western

hemlock and 129 for Douglas fir. The highest

average growth rate in unmanaged, even-aged stands of

western hemlock is 248 cubic feet per acre per year,

occurring at age 50. For Douglas fir, it is 180 cubic feet per

acre per year, occurring at age 60.

The main limitation affecting timber harvesting is

occasional snowpack. During an average year, the

snowpack limits the use of equipment and restricts access

from January through March. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Logging roads require suitable surfacing for

year-round use. Rounded pebbles and cobbles for road

construction are readily available. Cut and fill slopes tend

to ravel when dry.

Seedling establishment and seedling mortality are the

main concerns affecting timber production. Reforestation

can be accomplished by planting western hemlock or

Douglas fir seedlings. A low content of moisture in the

surface layer during the growing season hinders the

survival of planted and naturally established seedlings. If

seed trees are available, natural reforestation of cutover

areas by western hemlock occurs readily. When openings

are made in the canopy, the uncontrolled invasion and

growth of competing plants can delay the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means.

This map unit is in capability subclass IVe.

79-Kickerville silt loam, 0 to 3 percent slopes. This

very deep, well drained soil is on outwash terraces. It

formed in a mixture of loess and volcanic ash over glacial

outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

Typically, the surface layer is dark brown silt loam 9

inches thick. The upper 13 inches of the subsoil is dark

yellowish brown silt loam. The lower 10 inches is dark

yellowish brown very gravelly loam. The substratum to a

depth of 60 inches is very gravelly sand. It is variegated

but is dominantly olive brown and dark grayish brown. The

depth to very gravelly sand or extremely gravelly loamy

sand ranges from 20 to 36 inches. In some areas the

surface layer is loam, gravelly silt loam, or gravelly loam. In

other areas the soil has a gravelly subsoil. In places the

substratum has 15 to 35 percent rock fragments, has 5 to

15 percent cobbles, or is very gravelly sandy loam.

Included in this unit are small areas of Barnhardt,

Birchbay, Clipper, Laxton, Shalcar, Fishtrap, and

Everett soils and small areas of Kickerville soils that

have a stony surface or have slopes of more than 3
percent. Included areas make up about 10 percent of the

total acreage.

Permeability is moderate in the upper part of the

Kickerville soil and very rapid in the substratum. Available

water capacity is high. The effective rooting depth is 60

inches. Runoff is very slow, and there is no hazard of

erosion.

This unit is used mainly for hay and pasture or as

cropland. It also is used as woodland and as a site for

homes.

This unit is suited to hay and pasture. It has few

limitations for this use.

The main limitation in the areas used as cropland is the

low available water capacity in the substratum. In summer,

irrigation is required for maximum production. The

principal crops grown are potatoes, corn silage, and

raspberries. If irrigated, this unit is suited to all crops

commonly grown in the survey area.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, and red alder. The common understory plants

are western swordfern, salal, red huckleberry,

Oregongrape, and creambush oceanspray.

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

index for Douglas fir is 149. On the basis of a 50-year site

curve, it is 119. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 157 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Rounded pebbles for road construction are

readily available. Logging roads require suitable surfacing

for year-around use.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

This unit is well suited to homesite development. If used

as a base for roads and streets, the soil can be mixed with

the underlying sand and gravel, which can increase the

strength and stability of the soil. In shallow

excavations special retainer walls may be needed to keep

cutbanks from caving. The main limitation on sites for

septic tank absorption fields is a poor filtering capacity in

the substratum. Installing the absorption field in fill

approved by the health district helps to compensate for this

limitation.

This map unit is in capability subclass Ilc.

80-Kickerville silt loam, 3 to 8 percent slopes. This

very deep, well drained soil is on outwash terraces. It

formed in a mixture of loess and volcanic ash over glacial

outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

Typically, the surface layer is dark brown silt loam 9

inches thick. The upper 13 inches of the subsoil is dark

yellowish brown silt loam. The lower 10 inches is dark

yellowish brown very gravelly loam. The substratum to a

depth of 60 inches is very gravelly sand. It is variegated

but is dominantly olive brown and dark grayish brown. The

depth to very gravelly sand or extremely gravelly loamy

sand ranges from 20 to 36 inches. In some areas the

surface layer is loam, gravelly silt loam, or gravelly loam. In

other areas the soil has a gravelly subsoil. In places the

substratum has 15 to 35 percent rock fragments, has 5 to

15 percent cobbles, or is very gravelly sandy loam.

Included in this unit are small areas of Barnhardt,

Birchbay, Clipper, Laxton, Shalcar, Fishtrap, and Everett

soils and small areas of Kickerville soils that have a stony

surface or have slopes of more than 8 percent or less than

3 percent. Included areas make up about 10 percent of the

total acreage.

Permeability is moderate in the upper part of the

Kickerville soil and very rapid in the substratum.

Available water capacity is high. The effective rooting

depth is 60 inches. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used mainly for hay and pasture or as

cropland. It also is used as woodland and as a site for

homes.

This unit is suited to hay and pasture. It has few

limitations for this use.

The main limitation in the areas used as cropland is the

low available water capacity. In. summer, irrigation is

required for maximum production. The principal crops grown

are potatoes, corn silage, and raspberries. If irrigated, this

unit is suited to all crops commonly grown in the survey

area.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, and red alder. The common understory plants
are western swordfern, salal, red huckleberry,

Oregongrape, and creambush oceanspray.

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

index for Douglas fir is 149. On the basis of a 50-year site

curve, it is 119. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 157 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rounded pebbles for road construction are

readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when-the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

This unit is well suited to homesite development. It has

few limitations. If used as a base for roads and streets, the

soil can be mixed with the underlying sand and gravel,

which can increase the strength and stability of the soil. In

shallow excavations special retainer walls may be needed

to keep cutbanks from caving. The main limitation on sites

for septic tank absorption fields is a poor filtering capacity

in the substratum. Installing the absorption field in fill

approved by the health district helps to compensate for this

limitation.

This map unit is in capability subclasses Ile,

nonirrigated, and Ille, irrigated.

81-Kickerville silt loam, 8 to 15 percent slopes. This

very deep, well drained soil is on outwash terraces. It

formed in a mixture of loess and volcanic ash over glacial

outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

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

leaves, and twigs 1.5 inches thick. The surface layer is very

dark brown silt loam 3 inches thick. The

upper 16 inches of the subsoil is dark yellowish brown

loam. The lower 5 inches is dark yellowish brown very

gravelly loam. The substratum to a depth of 60 inches is

extremely gravelly sand. It is variegated but is dominantly

dark yellowish brown and olive brown. The depth to very

gravelly sand or extremely gravelly sand ranges from 20 to

36 inches. In some areas the surface layer is loam,

gravelly silt loam, or gravelly loam. In other areas the soil

has a gravelly subsoil. In places the substratum is very

gravelly sandy loam, has 15 to 35 percent rock fragments,

or has 5 to 15 percent cobbles.

Included in this unit are small areas of Barnhardt,

Birchbay, Laxton, and Everett soils and small areas of

Kickerville soils that have a stony surface or have slopes of

more than 15 percent or less than 8 percent. These

included areas make up about 10 percent of the total

acreage. Also included are soils that have slopes of 15 to

30 percent. These soils are in narrow, elongated areas

along terrace escarpments. They make up an additional 3

percent of the total unit.

Permeability is moderate in the upper part of the

Kickerville soil and very rapid in the substratum. Available

water capacity is high. The effective rooting depth is 60

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

is moderate.

This unit is used mainly for hay and pasture or as

woodland. It also is used as a site for homes.

The main limitations in the areas used for hay and

pasture are the low available water capacity and the

hazard of water erosion during periods of reestablishment.

Grazing when the soil is wet results in compaction of the

surface layer and poor tilth. In summer, irrigation is

required for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, and red alder. The common understory plants are

western swordfern, salal, red huckleberry, Oregongrape, and

creambush oceanspray.

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

index for Douglas fir is 149. On the basis of a 50-year site

curve, it is 119. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 157 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet causes

excessive rutting. Using low-pressure ground equipment can

minimize damage to the soil. Unsurfaced roads are soft

when wet and are subject to deep rutting during rainy

periods. Logging roads require suitable surfacing for yearround use. Rounded pebbles for road construction are

readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high
degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

The main limitation affecting homesite development is

the slope. In shallow excavations special retainer walls

may be needed to keep cutbanks from caving. If used as a

base for roads and streets, the soil can be mixed with the

underlying sand and gravel, which can increase the

strength and stability of the soil. The main limitation on

sites for septic tank absorption fields is a poor filtering

capacity in the substratum. Installing the absorption field in

fill approved by the health district helps to compensate for

this limitation. The slope affects the installation of septic

tank absorption fields. The absorption lines should be

installed on the contour.

This map unit is in capability subclasses Ille,

nonirrigated, and IVe, irrigated.

82-Kickerville-Urban land complex, 0 to 3 percent

slopes. This map unit is on outwash terraces. The native

vegetation is mainly conifers and shrubs. Elevation is 60 to

100 feet. The average annual precipitation is about 35

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

This unit is 50 percent Kickerville silt loam and 30

percent Urban land. The components of this unit occur as

areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Chuckanut,

Clipper, Birchbay, Nati, Everett, and Whatcom soils and

small areas of Kickerville soils that have slopes of more

than 3 percent. Included areas make up about 20 percent

of the total acreage.

The Kickerville soil is very deep and well drained. It

formed in a mixture of loess and volcanic ash over glacial

outwash. Typically, the surface layer is dark brown silt

loam 9 inches thick. The upper 13 inches of the subsoil is

dark yellowish brown silt loam. The lower 10 inches is dark

yellowish brown very gravelly loam. The substratum to a

depth of 60 inches is very gravelly sand. It is variegated

but is dominantly olive brown and

dark grayish brown. The depth to very gravelly sand ranges

from 20 to 36 inches. In some areas the surface layer is

loam, gravelly silt loam, or gravelly loam. In other areas the

soil has a gravelly subsoil. In places the substratum has 15

to 35 percent rock fragments, has 5 to 15 percent cobbles,

or is very gravelly sandy loam.

Permeability is moderate in the upper part of the

Kickerville soil and very rapid in the substratum. Available

water capacity is high. The effective rooting depth is 60

inches. Runoff is very slow, and there is no hazard of

erosion.

The Urban land consists of areas covered by streets,

buildings, parking lots, and other structures that so obscure

the soils that identification of the soil series is not feasible.

The Kickerville soil is used for lawns, gardens, parks, or

vacant lots.

This unit is well suited to homesite development. It has

few limitations. In shallow excavations special retainer

walls may be needed to keep cutbanks from caving. If

used as a base for roads and streets, the Kickerville soil

can be mixed with the underlying sand and gravel, which

can increase the strength and stability of the soil. The

main limitation on sites for septic tank absorption fields is

a poor filtering capacity in the substratum. Installing the

absorption field in fill approved by the health district helps

to compensate for this limitation.

The Kickerville soil is in capability subclass IIc. The

Urban land is in capability subclass VIIIs.

83-Kindy gravelly silt loam, 8 to 30 percent slopes.

This moderately deep, moderately well drained soil is on

high mountain back slopes and plateaus. It formed in a

mixture of volcanic ash, loess, and colluvium over glacial

till. The native vegetation is mainly conifers and shrubs.

Elevation is 1,800 to 2,700 feet. The average annual

precipitation is about 80 inches, the average annual air

temperature is about 43 degrees F, and the average frostfree period is about 105 days.

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

twigs 6 inches thick. When mixed to a depth of 4 inches, the

surface layer is brown gravelly silt loam. The upper 7 inches

of the subsoil is brown very gravelly silt loam. The lower 14

inches is yellowish brown very gravelly loam. Dense glacial

till that crushes to very gravelly loam is at a depth of 25

inches. The depth to dense glacial till ranges from 20 to 40

inches. The dense glacial till is similar to a cemented pan. In

some areas the surface layer is gravelly loam, very gravelly

loam, or very gravelly silt loam. In other areas the soil has

less than 35 percent rock fragments in the subsoil, has

dominantly phyllite or dunite rock fragments
in the subsoil and in the dense glacial till, or is 40 to 60

inches deep over bedrock or dense glacial till.

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

Hozomeen, Klawatti, and Springsteen soils, Rock outcrop,

and Kindy soils that have slopes of more than 30 percent or

less than 8 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the upper part of the Kindy

soil and very slow in the dense glacial till. Available water

capacity is moderate. The effective rooting depth is 20 to

40 inches. Water is perched above the dense glacial till

from November through April. Runoff is slow, and the

hazard of water erosion is slight.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Douglas fir, Pacific silver fir, and western redcedar. The

common understory plants are tall blue huckleberry,

salmonberry, deer fern, western brackenfern, red

huckleberry, and salal.

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

index is 135 for western hemlock and 120 for Douglas fir.

On the basis of a 50-year site curve, it is 96 for western

hemlock and 95 for Douglas fir. The highest average

growth rate in unmanaged, even-aged stands

of western hemlock is 209 cubic feet per acre per year,

occurring at age 50. For Douglas fir, it is 115 cubic feet per

acre per year, occurring at age 60. Areas on ridgetops that

are subject to strong, persistent winds are less productive

than the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal wetness.

During an average year, the snowpack limits the use of

equipment and restricts access from December through

April. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Steep

skid trails and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. Carefully laying out roads and

skid trails, properly timing their use, and using low-pressure

ground equipment can reduce the degree of compaction

and puddling.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting

timber production. A low soil temperature, deep

snowpack, and a short growing season hinder the

survival of planted and natural seedlings and delay their

establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting western hemlock or Pacific silver fir seedlings. If

seed trees are available, natural reforestation of cutover

areas by western hemlock and Pacific silver fir occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

delay the establishment of seedlings. Competing vegetation

can be controlled by mechanical or chemical means.

Because the rooting depth is restricted by the dense glacial

till, trees are occasionally subject to windthrow when the

soil is wet and winds are strong.

This map unit is in capability subclass VIe.

84-Kindy gravelly silt loam, 30 to 60 percent slopes.

This moderately deep, moderately well drained soil is on

high mountain back slopes and plateaus. It formed in a

mixture of volcanic ash, loess, and colluvium over glacial

till. The native vegetation is mainly conifers and shrubs.

Elevation is 1,800 to 2,700 feet. The average annual

precipitation is about 80 inches, the average annual air

temperature is about 43 degrees F, and the average frostfree period is about 105 days.

Typically, the surface is covered with a mat of needles

and twigs 6 inches thick. When mixed to a depth of 4

inches, the surface layer is brown gravelly silt loam. The

upper 7 inches of the subsoil is brown very gravelly silt

loam. The lower 14 inches is yellowish brown very gravelly

loam. Dense glacial till that crushes to very gravelly loam is

at a depth of 25 inches. The depth to dense glacial till

ranges from 20 to 40 inches. The dense glacial till is similar

to a cemented pan. In some areas the surface layer is

gravelly loam, very gravelly loam, or very gravelly silt loam.

In other areas the soil has less than 35 percent rock

fragments in the subsoil, has dominantly phyllite or dunite

rock fragments in the subsoil and in the dense glacial till, or

is 40 to 60 inches deep over bedrock or dense glacial till.

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

Hozomeen, Klawatti, and Springsteen soils, Rock outcrop,

and Kindy soils that have slopes of more than 60 percent

or less than 30 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the upper part of the

Kindy soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from November through

April. Runoff is medium, and the hazard of water

erosion is moderate.
This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Douglas fir, Pacific silver fir, and western redcedar.

The common understory plants are tall blue huckleberry,

salmonberry, deer fern, western brackenfern, red

huckleberry, and salal.

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

index is 135 for western hemlock and 120 for Douglas fir.

On the basis of a 50-year site curve, it is 96 for western

hemlock and 95 for Douglas fir. The highest average

growth rate in unmanaged, even-aged stands of western

hemlock is 209 cubic feet per acre per year, occurring at

age 50. For Douglas fir, it is 115 cubic feet per acre per

year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from December through April. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces

natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and cable yarding paths, properly timing

their use, and using cable systems that lift logs entirely off

the ground can reduce the degree of compaction and

puddling. Steep yarding paths, skid trails, and firebreaks

are subject to rilling and gullying unless adequate water

bars are provided or a protective plant cover is established.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. If seed trees

are available, natural reforestation of cutover areas by

western hemlock and

Pacific silver fir occurs periodically. When openings are

made in the canopy, the uncontrolled invasion and growth

of competing plants can delay the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the dense glacial till, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

This map unit is in capability subclass VIIe.

85-Kindy-Oso complex, 5 to 40 percent slopes.

This map unit is on high mountain back slopes and

plateaus. The native vegetation is mainly conifers and

shrubs. Elevation is 1,800 to 2,700 feet. The average

annual precipitation is about 80 inches, the average

annual air temperature is about 43 degrees F, and the

average frost-free period is about 105 days.

This unit is 50 percent Kindy gravelly silt loam and 35

percent Oso silt loam. The components of this unit occur

as areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of soils that are less

than 20 inches deep to dense glacial till or bedrock, Rock

outcrop, soils that are similar to the Kindy or Oso soil but

are deeper than 40 inches, and Kindy and Oso soils that

have slopes of more than 40 percent or less than 5

percent. Included areas make up about 15 percent of the

total acreage.

The Kindy soil is moderately deep and moderately well

drained. It formed in a mixture of volcanic ash, loess, and

colluvium over glacial till. Typically, the surface is covered

with a mat of needles and twigs 1 inch :thick. The surface

layer is dark brown gravelly silt loam 4 inches thick. The

upper 6 inches of the subsoil is dark reddish brown gravelly

silt loam. The lower 17 inches is dark brown and dark

reddish brown very gravelly silt loam. Dense glacial till that

crushes to very gravelly loam is at a depth of 27 inches.

The depth to dense glacial till ranges from 20 to 40 inches.

The dense glacial till is similar to a cemented pan. In some

areas the surface layer is gravelly loam or very gravelly

loam. In other areas the soil has less than 35 percent rock

fragments in the subsoil or is 40 to 60 inches deep to

dense glacial till.

Permeability is moderate in the upper part of the Kindy

soil and very slow in the dense glacial till. Available water

capacity is moderate. The effective rooting depth is 20 to

40 inches. Water is perched above the dense glacial till

from November through April. Runoff is slow, and the

hazard of water erosion is slight.

The Oso soil is moderately deep and well drained. It

formed in volcanic ash, loess, glacial till, and colluvium
derived from metasedimentary rocks. Typically, the surface

is covered with a mat of needles and twigs 4 inches thick.

When mixed to a depth of 3 inches, the surface layer is

dark reddish brown silt loam. The upper 11 inches of the

subsoil is dark brown gravelly silt loam. The lower 24

inches is dark yellowish brown gravelly silt loam.

Metasedimentary rock is at a depth of about 38 inches.

The depth to bedrock ranges from 20 to 40 inches. In some

areas the surface layer is gravelly silt loam. In other areas

the soil has 15 to 35 percent pebbles throughout the

subsoil or is 40 to 60 inches deep over bedrock.

Permeability is moderate in the Oso soil. Available

water capacity is moderate. The effective rooting depth is

20 to 40 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Douglas fir, Pacific silver fir, and western redcedar.

The common understory plants are tall blue huckleberry,

salmonberry, deer fern, western brackenfern, red

huckleberry, and salal.

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

index on the Kindy soil is 135 for western hemlock and 120

for Douglas fir. On the basis of a 50-year site curve, it is 96

for western hemlock and 95 for Douglas fir. The highest

average growth rate in unmanaged, even-aged stands of

western hemlock is 209 cubic feet per acre per year,

occurring at age 50. For Douglas fir, it is 115 cubic feet per

acre per year, occurring at age 60.

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

index for western hemlock on the Oso soil is 129. On the

basis of a 50-year site curve, it is 93. The highest average

growth rate in unmanaged, even-aged stands of western

hemlock is 198 cubic feet per acre per year, occurring at

age 50. Areas on ridgetops that are subject to strong,

persistent winds are less productive than the other areas of

this unit.

The main limitations affecting timber harvesting are

snowpack and muddiness caused by the seasonal wetness.

During an average year, the snowpack limits the use of

equipment and restricts access from December through

April. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is readily available. Cut and fill slopes tend to

slump when wet.

Equipment and logs on the surface result in a

moderate degree of compaction when the soils are

moist and a moderate degree of puddling when the

soils are wet. Steep skid trails and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. If seed trees

are available, natural reforestation of cutover areas by

western hemlock and Pacific silver fir occurs periodically.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the dense glacial till or the

bedrock, trees are occasionally subject to windthrow when

the soils are wet and winds are strong.

The Kindy and Oso soils are in capability subclass

VIe.

86-Klawatti very gravelly loam, 30 to 60 percent

slopes. This moderately deep, well drained soil is on high

mountain shoulder slopes and ridges. It formed in volcanic

ash, slope alluvium, and colluvium derived dominantly from

dunite. The native vegetation is mainly conifers and shrubs.

Elevation is 2,600 to 4,200 feet. The average annual

precipitation is about 95 inches, the average annual air

temperature is about 41 degrees F, and the average frostfree period is about 95 days.

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

twigs, and bark 7 inches thick. When mixed to a depth of

7 inches, the surface layer is dark yellowish brown very

gravelly loam. The subsoil is dark yellowish brown

extremely gravelly silt loam 18 inches thick. Dunite is at a

depth of about 25 inches. The depth to bedrock ranges

from 20 to 40 inches. In some areas the surface layer is

very gravelly silt loam. In other areas the soil is 40 to 60

inches deep over bedrock.

Included in this unit are small areas of Twinsi, Jackman,

and Edfro soils, Rock outcrop, soils that are shallow to

dunite, and Klawatti soils that have slopes of more than 60

percent or less than 30 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the Klawatti soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and
the hazard of water erosion is moderate.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Alaska cedar, and mountain hemlock.

The common understory plants are blueleaved huckleberry,

red huckleberry, princes pine, and western brackenfern.

Vegetation is somewhat stunted and sparse because of the

toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces

natural fertility and the available water capacity. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Rock for road construction is readily

available. Cut and fill slopes tend to slump when wet. Soil

creep is common on this unit.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of other

important minerals, and a low content of moisture in the

surface layer during the growing season hinder the survival

of planted and naturally established seedlings. A low soil

temperature, deep snowpack, and a short growing season

also hinder the survival of the seedlings and delay their

establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting western hemlock, Pacific silver fir, or Alaska

cedar seedlings, which are adapted to the toxicity of dunite

soils. If seed trees are available, natural reforestation of

cutover areas by western

hemlock, mountain hemlock, Pacific silver fir, and Alaska

cedar occurs periodically. Trees grow poorly and lack vigor

on soils that are derived from dunite. Planting seedlings in

the organic layer improves growth and vigor. Because the

rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIle.

87-Klawatti very gravelly loam, serpentine, 10 to 30

percent slopes. This moderately deep, well drained soil is

on high mountain shoulder slopes and ridges. It formed in

volcanic ash, colluvium, and slope alluvium derived

dominantly from serpentine. The native vegetation is mainly

conifers and shrubs. Elevation is 2,000 to 4,300 feet. The

average annual precipitation is about 90 inches, the

average annual air temperature is about 41 degrees F, and

the average frost-free period is about 100 days.

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

leaves, and twigs 2 inches thick. When mixed to a depth

of 7 inches, the surface layer is dark yellowish brown very

gravelly loam. The subsoil is dark yellowish brown

extremely gravelly silt loam 18 inches thick. Serpentine is

at a depth of about 25 inches. The depth to serpentine

ranges from 20 to 40 inches. In some areas the surface

layer is very gravelly silt loam. In other areas the soil is 40

to 60 inches deep over bedrock.

Included in this unit are small areas of Edfro, Twinsi,

Crinker, Jackman, and Saar soils, Rock outcrop, soils that

are shallow to serpentine, and Klawatti soils that have

slopes of more than 30 percent or less than 10 percent.

Included areas make up about 15 percent of the total

acreage.

Permeability is moderate in the Klawatti soil. Available

water capacity is moderate. The effective rooting depth is

20 to 40 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Alaska cedar, and mountain hemlock.

The common understory plants are blueleaved huckleberry,

red huckleberry, princes pine, and western brackenfern.

Vegetation is somewhat stunted and sparse because of the

toxicity of the serpentine-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds
are less productive than the other areas of this unit.

The main limitation affecting timber harvesting is

snowpack. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. Because most of the roots are concentrated

in the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is readily available. Cut and fill slopes tend to

slump when wet. Steep skid trails and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of other

important minerals, and a low content of moisture in the

surface layer during the growing season hinder the survival

of planted and naturally established seedlings. A low soil

temperature, deep snowpack, and a short growing season

also hinder the survival of the seedlings and delay their

establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting western hemlock, Pacific silver fir, or Alaska

cedar seedlings, which are adapted to the toxicity of

serpentine soils. If seed trees are available, natural

reforestation of cutover areas by western hemlock,

mountain hemlock, Pacific silver fir, and Alaska cedar

occurs periodically. Trees grow poorly and lack vigor on

soils that are derived from serpentine. Because the rooting

depth is restricted by the bedrock, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

This map unit is in capability subclass VIe.

88-Klawatti very gravelly loam, serpentine, 30 to 60

percent slopes. This moderately deep, well drained soil is

on high mountain shoulder slopes and ridges. It formed in

volcanic ash, colluvium, and slope alluvium derived

dominantly from serpentine. The native vegetation is mainly

conifers and shrubs. Elevation is 2,200 to 4,300 feet. The

average annual precipitation is about 90 inches, the

average annual air temperature is about 41 degrees F, and

the average frost-free period is about 100 days.

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

leaves, and twigs 2 inches thick. When mixed to a depth of

7 inches, the surface layer is dark yellowish brown very

gravelly loam. The subsoil is dark yellowish brown

extremely gravelly silt loam 18 inches thick. Serpentine is

at a depth of about 25 inches. The

depth to serpentine ranges from 20 to 40 inches. In some

areas the surface layer is very gravelly silt loam. In other

areas the soil is 40 to 60 inches deep over bedrock.

Included in this unit are small areas of Edfro, Twinsi,

Crinker, Jackman, and Saar soils, Rock outcrop, soils that

are shallow to serpentine, and Klawatti soils that have

slopes of more than 60 percent or less than 30 percent.

Included areas make up about 15 percent of the total

acreage.

Permeability is moderate in the Klawatti soil. Available

water capacity is moderate. The effective rooting depth is

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

erosion is moderate.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Alaska cedar, and mountain hemlock.

The common understory plants are blueleaved huckleberry,

red huckleberry, princes pine, and western brackenfern.

Vegetation is somewhat stunted and sparse because of the

toxicity of the serpentine-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the hazard of slumping, the slope, and the

hazard of erosion. During an average year, the snowpack

limits the use of equipment and restricts access from

November through May. This unit is prone to landslides

and deep-seated rotational slumping because of the deep

fractures in the serpentine that have resulted from faulting

planes in the rock. When timber is harvested, the slope

restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Because most of the

roots are concentrated in the organic mat, loss of this layer

during logging greatly reduces natural fertility and the

available water capacity. Unsurfaced roads are soft when

wet and are subject to deep rutting during rainy periods.

Rock for road construction is readily available. Cut and fill

slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Steep yarding paths, skid trails, and firebreaks
are subject to rifling and gullying unless adequate water

bars are provided or a protective plant cover is

established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of

other important minerals, and a low content of moisture in

the surface layer during the growing season hinder the

survival of planted and naturally established seedlings. A

low soil temperature, deep snowpack, and a short growing

season also hinder the survival of the seedlings and delay

their establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting western hemlock, Pacific silver

fir, or Alaska cedar seedlings, which are adapted to the

toxicity of serpentine soils. If seed trees are available,

natural reforestation of cutover areas by western hemlock,

mountain hemlock, Pacific silver fir, and Alaska cedar

occurs periodically. Trees grow poorly and lack vigor on

soils that are derived from serpentine. Because the rooting

depth is restricted by the bedrock, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

This map unit is in capability subclass VIle.

89-Klawatti-Rock outcrop complex, 60 to 80 percent

slopes. This map unit is on high mountain shoulder

slopes and ridges. The native vegetation is mainly conifers

and shrubs. Elevation is 2,200 to 4,300 feet. The average

annual precipitation is about 90 inches, the average

annual air temperature is about 41 degrees F, and the

average frost-free period is about 100 days.

This unit is 55 percent Klawatti very gravelly loam and

25 percent Rock outcrop. The components of this unit

occur as areas so intricately intermingled that mapping

them separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Twinsi, Crinker,

Jackman, and Saar soils, soils that are shallow to

serpentine, stony areas, and Klawatti soils that have slopes

of less than 60 percent. Included areas make up about 20

percent of the total acreage.

The Klawatti soil is moderately deep and well drained.

It formed in volcanic ash, colluvium, and slope alluvium

derived dominantly from serpentine. Typically, the surface

is covered with a mat of needles and twigs 2 inches thick.

When mixed to a depth of 7 inches, the surface layer is

dark yellowish brown very gravelly loam. The subsoil is

dark yellowish brown extremely gravelly loam 13 inches

thick. The substratum is dark yellowish brown very

gravelly loam 8 inches thick.

Serpentine is at a depth of about 28 inches. The depth to

serpentine ranges from 20 to 40 inches. In some areas

the surface layer is very gravelly silt loam. In other areas

the soil is 40 to 60 inches deep over bedrock.

Permeability is moderate in the Klawatti soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is rapid, and the hazard of water

erosion is severe.

Typically, the Rock outcrop is serpentine, although in

some areas it is phyllite. It is hard and generally

unweathered. It occurs as steep cliffs and irregular

formations.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, mountain hemlock, and Alaska cedar.

The common understory plants are blueleaved

huckleberry, red huckleberry, princes pine, and western

brackenfern. Vegetation is somewhat stunted and sparse

because of the toxicity of the serpentine-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Yields are reduced by the

extent of the Rock outcrop. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are the

hazard of slumping, the Rock outcrop, the slope, snowpack,

and the hazard of erosion. During an average year, the

snowpack limits the use of equipment and restricts access

from November through May. This unit is prone to

landslides and deep-seated rotational slumping because of

the deep fractures in the serpentine that have resulted from

faulting planes in the rock. Cable yarding systems generally

are used on this unit. The pattern of the Rock outcrop on

the landscape results in a discontinuous slope, which

hinders the use of cable yarding systems. The trees can

break if they are felled on the Rock outcrop. Because most

of the roots are concentrated in the organic mat, loss of this

layer during logging greatly reduces natural fertility and the

available water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is readily available. Cut and fill slopes tend to

slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit. Locating roads on midslopes

requires extensive cutting and filling, which remove land

from production. Carefully laying out roads
and cable yarding paths, properly timing their use, and

using cable systems that lift logs entirely off the ground

reduce the hazard of erosion. Steep yarding paths, skid

trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of

other important minerals, and a low content of moisture in

the surface layer during the growing season hinder the

survival of planted and naturally established seedlings. A

low soil temperature, deep snowpack, and a short growing

season also hinder the survival of the seedlings and delay

their establishment. The seedling mortality rate is higher

on ridgetops that are subject to strong, persistent winds

than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock, Pacific silver fir, or Alaska cedar seedlings,

which are adapted to the toxicity of serpentine soils.

Because of the Rock outcrop and the slope, planting

seedlings by hand is difficult. If seed trees are available,

natural reforestation of cutover areas by western hemlock,

mountain hemlock, Pacific silver fir, and Alaska cedar

occurs periodically. Trees grow poorly and lack vigor on

soils that are derived from serpentine. The Rock outcrop

prevents the even distribution of reforestation. Because

the rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the Klawatti soil is

wet and winds are strong.

The Klawatti soil is in capability subclass VIle. The

Rock outcrop is in capability subclass Vllls.

90-Kline gravelly sandy loam, 2 to 8 percent slopes.

This very deep, moderately well drained soil is on alluvial

fans. It formed in mixed alluvium. It is partially protected

from flooding. The native vegetation is mainly conifers and

shrubs. Elevation is 100 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 frostfree period is about 170 days.

Typically, when mixed to a depth of 9 inches, the

surface layer is dark brown and olive brown gravelly sandy

loam. The upper 11 inches of the underlying material is

dark brown extremely gravelly loamy sand. The lower part

to a depth of 60 inches is dark grayish brown stratified

very gravelly loamy sand and very gravelly sand. Depth to

the underlying material ranges from 8 to 20 inches. In

some areas the surface layer is gravelly loam. In other

areas the soil has strata within the underlying material with

less than 35 percent rock

fragments or has 15 to 35 percent phyllite rock

fragments.

Included in this unit are small areas of Sehome,

Whatcom, and Briscot soils and small areas of Kline soils

that are not protected from flooding or have slopes of more

than 8 percent or less than 2 percent. Included areas make

up about 15 percent of the total acreage.

Permeability is moderately rapid in the upper part of the

Kline soil and very rapid in the underlying material.

Available water capacity is low. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 3 to 5 feet from January through March. Runoff is

slow, and the hazard of water erosion is slight. In most

areas this soil is subject to rare flooding. In some

unprotected areas, however, it is subject to occasional,

very brief periods of flooding from December through March.

This unit is used mainly for hay and pasture or as

woodland. It also is used as cropland and as a site for

homes.

The main limitation in the areas used for hay and

pasture is the low available water capacity. Proper

stocking rates, pasture rotation, and restricted grazing

during wet periods help to keep the pasture in good

condition.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western redcedar, and

western hemlock. The common understory plants are salal,

red huckleberry, western brackenfern, western swordfern,

trailing blackberry, and Oregongrape.

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

index for Douglas fir is estimated to be 124. On the basis

of a 50-year site curve, it is estimated to be 106. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 121 cubic feet per acre per

year, occurring at age 70.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are somewhat soft when wet and are subject to deep

rutting during rainy periods. Logging roads require suitable

surfacing for year-round use. Rounded pebbles and

cobbles for road construction are readily available.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of soil displacement when the soil is dry.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and displacement.

Seedling establishment and seedling mortality are the

main concerns affecting timber production. A low
content of moisture in the surface layer during the growing

season hinders the survival of planted and naturally

established seedlings. Reforestation can be accomplished

by planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. The survival rate of seedlings may be

low in areas where flooding occurs.

The main limitations in the areas used as cropland are

the low available water capacity and the seasonal high

water. The principal crop is corn silage. If irrigated, this soil

is suited to other climatically adapted crops. Because of

the inherent low fertility, this unit requires proportionately

more fertilizer than most other soils in the survey area to

produce similar yields. The pebbles in the surface layer

make tillage difficult and can cause equipment damage.

The wetness can be reduced in some areas by diversions,

which intercept water, and by open ditches, which remove

excess water. In summer, irrigation is required for

maximum production.

The main limitation for homesite development is the

hazard of flooding. In shallow excavations special retainer

walls may be needed to keep cutbanks from caving. The

main limitations on sites for septic tank absorption fields

are a poor filtering capacity in the substratum and the

seasonal high water table. Septic tank absorption fields

may not function properly during rainy periods because of

the wetness. These limitations can be overcome by using

interceptor drains, by installing the absorption field at a

shallow depth, and by installing absorption lines that are

longer than normal and that are on the contour. During the

rainy season, the effluent from onsite sewage disposal

systems can seep at points downslope.

This map unit is in capability subclass IVs.

91-Kulshan loam, 5 to 30 percent slopes. This

moderately deep, well drained soil is on mountain back

slopes and ridges. It formed in volcanic ash, loess,

colluvium, and slope alluvium derived dominantly from

sandstone. The native vegetation is mainly conifers and

shrubs. Elevation is 3,500 to 5,000 feet. The average

annual precipitation is about 100 inches, the average

annual air temperature is about 40 degrees F, and the

average frost-free period is about 85 days.

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

leaves, twigs, and bark 7 inches thick. When mixed to a

depth of 8 inches, the surface layer is dark red loam. The

upper 6 inches of the subsoil is organic stained, yellowish

red gravelly loam. The lower 16

inches is yellowish red and dark reddish brown gravelly

loam and cobbly loam. Sandstone is at a depth of about 30

inches. The depth to sandstone ranges from 20 to 40

inches. In some areas the surface layer is silt loam or

gravelly loam. In other areas the soil has a very gravelly

subsoil or is 40 to 60 inches deep over bedrock.

Included in this unit are small areas of Shuksan,

Potchub, and Gallup soils, soils that are less than 20

inches deep over bedrock, poorly drained mineral and

organic soils in depressions, Rock outcrop, and Kulshan

soils that have slopes of more than 30 percent or less than

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

total acreage.

Permeability is moderate in the Kulshan soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among

the trees of limited extent is mountain hemlock. The

common understory plants are blueleaved huckleberry,

bunchberry dogwood, and longtube twinflower..

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

index for western hemlock is estimated to be 93. On the

basis of a 50-year site curve, it is estimated to be 65. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 110 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitation affecting timber harvesting is

snowpack. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. The use of wheeled and tracked equipment

when the soil is wet causes excessive rutting. Using lowpressure ground equipment can minimize damage to the

soil. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Sandstone, a poor-quality

rock for road construction, is readily available. Cut and fill

slopes tend to slump when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling. Steep skid

trails and firebreaks are subject to rilling and
gullying unless adequate water bars are provided or a

protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are subject

to strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Pacific silver fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. Because

the rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass Vls.

92-Kulshan loam, 30 to 60 percent slopes. This

moderately deep, well drained soil is on mountain back

slopes and ridges. It formed in volcanic ash, loess,

colluvium, and slope alluvium derived dominantly from

sandstone. The native vegetation is mainly conifers and

shrubs. Elevation is 3,500 to 5,000 feet. The average

annual precipitation is about 100 inches, the average

annual air temperature is about 40 degrees F, and the

average frost-free period is about 85 days.

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

leaves, twigs, and bark 7 inches thick. When mixed to a

depth of 8 inches, the surface layer is dark red loam. The

upper 6 inches of the subsoil is organic stained, yellowish

red gravelly loam. The lower 16 inches is yellowish red and

dark reddish brown gravelly loam and cobbly fine sandy

loam. Sandstone is at a depth of about 30 inches. The

depth to sandstone ranges from 20 to 40 inches. In some

areas the surface layer is silt loam or gravelly loam. In

other areas the soil has a very gravelly subsoil or is 40 to

60 inches deep over bedrock.

Included in this unit are small areas of Shuksan, Potchub,

and Gallup soils, soils that are less than 20 inches deep

over bedrock, poorly drained mineral and organic soils in

depressions, Rock outcrop, and Kulshan soils that have

slopes of more than 60 percent or less than 30 percent.

Included areas make up about 15 percent of the total

acreage.

Permeability is moderate in the Kulshan soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the

hazard of water erosion is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent is mountain hemlock. The common

understory plants are blueleaved huckleberry,

bunchberry dogwood, and longtube twinflower.

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

index for western hemlock is estimated to be 93. On the

basis of a 50-year site curve, it is estimated to be 65. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 110 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft when wet and are subject to deep rutting during

rainy periods. Sandstone, a poor-quality rock for road

construction, is readily available. Cut and fill slopes tend to

slump when wet. Soil creep is common on this unit.

Seedling mortality is the main concern affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are subject

to strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock or Pacific silver fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. Because

the rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIle.

93-Labounty silt loam, 0 to 2 percent slopes. This

very deep, poorly drained soil is in depressions on

glaciomarine drift plains. It formed in glaciomarine drift with

an admixture of loess and volcanic ash. The native

vegetation is mainly trees and shrubs. Elevation is 50 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 period is about 170

days.

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

leaves, and twigs 3 inches thick. The surface layer is dark

brown silt loam 12 inches thick. The upper
3 inches of the subsoil is dark grayish brown, mottled silt

loam. The lower 14 inches is grayish brown, mottled silt

loam. The substratum to a depth of 60 inches is grayish

brown and light brownish gray loam. In some areas the

surface layer is loam. In other areas the soil has 10 to 18

percent or 35 to 45 percent clay in the subsoil and

substratum, has lenses of sand in the substratum, or has 5

to 15 percent cobbles in the substratum.

Included in this unit are small areas of Whatcom and

Hale soils and small areas of Labounty soils that have

been artificially drained. Included areas make up about 15

percent of the total acreage.

Permeability is moderately slow in the Labounty soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at or

near the surface from November through May. Runoff is

very slow, and there is no hazard of erosion.

This unit is used as woodland. Red alder is the main

woodland species. Among the trees of limited extent are

western hemlock, western redcedar, and Douglas fir. The

common understory plants are salmonberry, western

brackenfern, western swordfern, red huckleberry,

sweetscented bedstraw, skunkcabbage, trailing blackberry,

and Douglas spirea.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the use

of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and may be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is needed

to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily and reforestation by western

hemlock occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the high water table, trees are frequently subject to

windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass VIw.

94-Labounty silt loam, drained, 0 to 2 percent slopes.

This very deep, poorly drained soil is in depressions on

glaciomarine drift plains. It has been artificially drained. It

formed in glaciomarine drift with an admixture of loess and

volcanic ash. The native vegetation is mainly trees and

shrubs. Elevation is 50 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 period is about 170 days.

Typically, the surface layer is very dark grayish brown silt

loam 10 inches thick. The upper 6 inches of the subsoil is

grayish brown and light brownish gray, mottled loam. The

lower 19 inches is grayish brown, olive gray, and light olive

gray, mottled loam. The substratum to a depth of 60 inches

is gray loam. In some areas the surface layer is loam. In

other areas the soil has a surface layer that is 5 to 8 inches

thick or is light colored. In places the substratum has lenses

of sandy material, has 10 to 18 percent or 35 to 45 percent

clay, or has 5 to 10 percent cobbles, stones, or boulders.

Included in this unit are small areas of Whatcom,

Bellingham, Hale, and Birchbay soils, Shalcar soils in

depressions, and undrained Labounty soils. Included

areas make up about 10 percent of the total acreage.

Permeability is moderately slow in the Labounty soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a depth

of 1 to 3 feet from November through May. Runoff is very

slow, and there is no hazard of erosion.

This unit is used for hay and pasture or as cropland. The

main limitations in the areas used for hay and pasture are

the high water table and the moderately slow permeability.

The principal crop is corn silage. The dominant method of

drainage in the areas used for hay and pasture is open

ditches. Maintaining artificial drainage systems permits

fieldwork to be conducted earlier in the spring and increases

the yields of perennial crops. The wetness can be reduced

in some areas by diversions, which intercept water, and by

open ditches, which remove excess water. Most crops

common to the survey area can be grown if the drainage

system is adequate. Returning all crop residue
to the soil and including grasses, legumes, or grasslegume mixtures in the cropping sequence help to

maintain fertility and tilth. During the growing season,

the water table is artificially lowered to a depth of about 3 to

5 feet.

This unit has potential as woodland. On the basis of a

50-year site curve, the mean site index for red alder is

estimated to be 90. The highest average growth rate in

unmanaged, even-aged stands of red alder is about 101

cubic feet per acre per year, occurring at age 40.

If this unit is used for homesite development, the main

limitation is the high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

The main limitations on sites for septic tank absorption

fields are the moderately slow permeability and the high

water table. Installing absorption lines that are longer than

normal helps to overcome these limitations.

This map unit is in capability subclass Ilw.

95-Larush silt loam, 0 to 2 percent slopes. This very

deep, well drained soil is on river terraces. It formed in

alluvium. The native vegetation is mainly conifers and

shrubs. Elevation is 200 to 500 feet. The average annual

precipitation is about 65 inches, the average annual air

temperature is about 49 degrees F, and the average frostfree period is about 180 days.

Typically, the surface layer is very dark grayish

brown silt loam 7 inches thick. The upper 18 inches of the

underlying material is very dark grayish brown and dark

grayish brown silt loam. The lower part to a depth of 60

inches is dark grayish brown sand and fine sand with thin

strata of silt loam. The depth to sand ranges from 15 to 30

inches. In some areas the surface layer is loam 'or fine

sandy loam. In other areas the substratum is stratified with

sandy loam or is gravelly.

Included in this unit are small areas of Briscot,

Barneston, Mt. Vernon, Oridia, Bellingham, and Shalcar

soils and Riverwash. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the Larush soil. Available

water capacity also is moderate. The effective rooting depth

is 60 inches. Runoff is very slow, and there is no hazard of

erosion. In most areas this soil is subject to occasional,

brief periods of flooding from November through April.

Some unprotected areas, however, are subject to frequent,

brief periods of flooding during this period. Channeling and

deposition are common along

streambanks.

This unit is used for hay and pasture, as woodland, or as

cropland. The main limitation when used for hay and

pasture is the hazard of flooding. Proper stocking rates,

pasture rotation, and restricted grazing during wet

periods help to keep the pasture in good condition.

Grazing when the soil is wet results in compaction of the

surface layer and poor tilth.

This unit is suited to cropland. It has few limitations.

The principal crops are corn silage and small grain. In

summer, irrigation is required for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, and bigleaf maple. The common

understory plants are western swordfern, western

brackenfern, vine maple, trailing blackberry, and longtube

twinflower.

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

index for Douglas fir is estimated to be 174. On the basis

of a 50-year site curve, it is estimated to be 131. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 185 cubic feet per acre per

year, occurring at age 60.

The main limitations for timber harvesting are the

occasional flooding and the muddiness caused by

seasonal wetness. These limit the use of equipment to dry

periods. The use of wheeled and tracked equipment during

periods when the soil is wet causes excessive rutting.

Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and are subject to deep rutting during rainy periods.

Logging roads require suitable surfacing for year-round

use. Rock for road construction is not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. The occasional flooding hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

If this unit is used for homesite development, the main

limitation is the hazard of flooding. In shallow

excavations special retainer walls may be needed to

keep cutbanks from caving. Dikes and channels that

have outlets to bypass floodwater can be used to protect

buildings and onsite sewage disposal systems from the

flooding.

This map unit is in capability subclass Ilw.
96-Laxton loam, 0 to 3 percent slopes. This very

deep, moderately well drained soil is on outwash terraces.

It formed in loess and volcanic ash over glacial outwash.

The native vegetation is mainly conifers and shrubs.

Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

Typically, the surface layer is dark yellowish brown loam

9 inches thick. The subsoil is dark brown and dark

yellowish brown silt loam 14 inches thick. The upper 9

inches of the substratum is olive brown, mottled loamy

sand. The lower part to a depth of 60 inches is mottled

sand. It is variegated but is dominantly olive brown, light

brownish gray, and dark grayish brown. The depth to sand

ranges from 20 to 40 inches. In some areas the surface

layer is silt loam or sandy loam. In other areas the soil has

a weakly cemented subsoil or substratum, has a combined

surface layer and subsoil thickness of 10 to 20 inches, or

has a water table below a depth of 3.5 feet.

Included in this unit are small areas of Hale and Yelm

soils and small areas of soils that are similar to the Laxton

soil but have a water table at a depth of 1.0 to 2.5 feet or

have slopes of more than 3 percent. Included areas make

up about 10 percent of the total acreage.

Permeability is moderate in the upper part of the

Laxton soil and very rapid in the substratum. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a depth

of 2.5 to 3.5 feet from November through April. Runoff is

very slow, and there is no hazard of erosion.

This unit is used mainly for hay and pasture, as

cropland, or as woodland. It also is used as a site for

homes.

The main limitation in the areas used for hay and

pasture is the seasonal high water table. Proper stocking

rates, pasture rotation, and restricted grazing during

short wet periods help to keep the pasture in good

condition and help to control runoff and erosion.

This unit is suited to cropland. It has few limitations.

The principal crops are raspberries, strawberries, and

sweet corn. In summer, irrigation is required for maximum

production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder, and

western redcedar. The common understory plants are

western swordfern, salal, Oregongrape, vine maple, red

huckleberry, and western brackenfern.

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

index for Douglas fir is estimated to be 160. On the basis

of a 50-year site curve, it is estimated to be 120. The

highest average growth rate, in unmanaged, evenaged stands of Douglas fir is about 170 cubic feet per

acre per year, occurring at age 65.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment during periods when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is

available. The main limitations on sites for septic tank

absorption fields are the seasonal high water table and a

poor filtering capacity in the substratum. Installing the

absorption field in fill approved by the health district helps

to compensate for these limitations.

This map unit is in capability subclass Ilw.

97-Laxton loam, 3 to 8 percent slopes. This very

deep, moderately well drained soil is on outwash terraces.

It formed in loess and volcanic ash over glacial outwash.

The native vegetation is mainly conifers and shrubs.

Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

Typically, the surface layer is dark yellowish brown loam

9 inches thick. The subsoil is dark brown and dark

yellowish brown silt loam 14 inches thick. The upper 9

inches of the substratum is olive brown, mottled loamy

sand. The lower part to a depth of 60 inches is mottled

sand. It is variegated but is dominantly olive brown, light

brownish gray, and dark grayish brown. The depth to
sand ranges from 20 to 40 inches. In some areas the

surface layer is silt loam or sandy loam. In other areas the

soil has a weakly cemented subsoil or substratum or has a

water table below a depth of 3.5 feet. In places the

combined thickness of the surface layer and subsoil is 10

to 20 inches.

Included in this unit are small areas of Hale and Yelm

soils and small areas of soils that are similar to the

Laxton soil but have a water table at a depth of 1.0 to 2.5

feet or have slopes of more than 8 percent or less than 3

percent. Included areas make up about 10 percent of the

total acreage.

Permeability is moderate in the upper part of the

Laxton soil and very rapid in the substratum. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 2.5

to 3.5 feet from November through April. Runoff is slow,

and the hazard of water erosion is slight.

This unit is used mainly for hay and pasture, as

cropland, or as woodland. It also is used as a site for

homes.

The main limitation in the areas used for hay and

pasture is the seasonal high water. Proper stocking rates,

pasture rotation, and restricted grazing during wet periods

help to keep the pasture in good condition. Grazing when

the soil is wet results in compaction of the surface layer

and poor tilth.

This unit is suited to cropland. It has few limitations.

This soil is well suited to raspberries, strawberries, and

sweet corn. In summer, irrigation is required for maximum

production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder, and

western redcedar. The common understory plants are

western swordfern, salal, Oregongrape, vine maple, red

huckleberry, and western brackenfern.

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

index for Douglas fir is estimated to be 160. On the basis

of a 50-year site curve, it is estimated to be 120. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 170 cubic feet per acre per

year, occurring at age 65.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

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

not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily and reforestation by western hemlock occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is

available. In shallow excavations special retainer walls

may be needed to keep cutbanks from

caving. The main limitations on sites for septic tank

absorption fields are the seasonal high water table and a

poor filtering capacity in the substratum, Installing the

absorption field in fill approved by the health district helps

to compensate for these limitations.

This map unit is in capability subclasses lIe,

nonirrigated, and Ille, irrigated.

98-Laxton loam, 8 to 15 percent slopes. This very

deep, moderately well drained soil is on outwash terraces.

It formed in loess and volcanic ash over glacial outwash.

The native vegetation is mainly conifers and shrubs.

Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

Typically, the surface layer is dark yellowish brown loam

11 inches thick. The subsoil is yellowish brown loam 25

inches thick. The upper 14 inches of the substratum is

olive brown, mottled sand. The lower part to a depth of 60

inches is mottled sand. It is variegated but is dominantly

light olive brown. The depth to sand ranges from 20 to 40

inches. In some areas the surface layer is silt loam or

sandy loam. In other areas the soil has a weakly cemented

subsoil or substratum, has a water table below a depth of

3.5 feet, or has more than 35 percent rock fragments in the

substratum. In places the combined thickness of the

surface layer and subsoil is 10 to 20 inches.

Included in this unit are small areas of Yelm soils and

small areas of soils that are similar to the Laxton soil but

have a water table at a depth of 1 to 2 feet or
have slopes of more than 15 percent or less than 8

percent. Included areas make up about 10 percent of

the total acreage.

Permeability is moderate in the upper part of the

Laxton soil and very rapid in the substratum. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a depth

of 2.5 to 3.5 feet from November through April. Runoff is

medium, and the hazard of water erosion is moderate.

This unit is used mainly for hay and pasture or as

woodland. It also is used as a site for homes.

The main limitations in the areas used for hay or crops

are the seasonal high water table and the hazard of

erosion during periods of reestablishment. Proper stocking

rates, pasture rotation, and restricted grazing during wet

periods help to keep the pasture in good condition. Grazing

when the soil is wet results in compaction of the surface

layer, poor tilth, and excessive runoff.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder, and

western redcedar. The common understory plants are

western swordfern, salal, Oregongrape, vine maple, red

huckleberry, and western brackenfern.

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

index for Douglas fir is estimated to be 160. On the basis

of a 50-year site curve, it is estimated to be 120. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 170 cubic feet per acre per

year, occurring at age 65.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting,

during rainy periods. Logging roads require suitable

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

not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

The main limitations affecting homesite development are

the seasonal high water table and the slope. In shallow

excavations special retainer walls may be needed to keep

cutbanks from caving. The wetness can be reduced by

building the house on a pad and by installing drainage tile

around footings if a suitable outlet is available. The main

limitations on sites for septic tank absorption fields are the

seasonal high water table and a poor filtering capacity in

the substratum. The slope affects the installation of septic

tank absorption fields. The absorption lines should be

installed on the contour. Installing the absorption field in fill

approved by the health district helps to compensate for

these limitations.

This map unit is in capability subclasses Ille,

nonirrigated, and IVe, irrigated.

99-Lynden sandy loam, 0 to 3 percent slopes. This

very deep, well drained soil is on outwash terraces. It

formed in loess and volcanic ash over glacial outwash. The

native vegetation is mainly conifers and shrubs. Elevation

is 50 to 300 feet. The average annual precipitation is about

45 inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface layer is dark brown sandy loam 8

inches thick. The subsoil is dark brown sandy loam 10

inches thick. The substratum is variegated sand. The upper

12 inches is dominantly very dark grayish brown, and the

lower part to a depth of 60 inches is dominantly dark

grayish brown. The depth to sand ranges from 14 to 24

inches. In some areas the surface layer is loam. In other

areas the soil has 15 to 25 percent pebbles in the

substratum. In some places the lower part of the subsoil,

the substratum, or both are weakly cemented, mottled, or

both. In other places the combined thickness of the surface

layer and subsoil is 24 to 36 inches or 8 to 14 inches.

Included in this unit are small areas of Hale, Tromp, and

Lynnwood soils and small areas of Lynden soils that have

slopes of more than 3 percent. Included areas make up

about 10 percent of the total acreage.

Permeability is moderately rapid in the upper part of

the Lynden soil and very rapid in the substratum.

Available water capacity is moderate. The effective

rooting depth is 60 inches. Runoff is very slow, and there

is no hazard of water erosion.

This unit is used mainly for hay and pasture, as

cropland, or as a site for homes. It also is used as

woodland.

The main limitation in the areas used for hay and

pasture is the moderate available water capacity.
The main limitations in the areas used as cropland are

the moderate available water capacity and the hazard of

erosion. The principal crops are raspberries, carrots, and

corn silage. Moisture retention can be improved by

mulching, rotating legumes with grain, and leaving residue

on slopes. Drip irrigation is the most suitable method of

applying water for crop production. In summer, irrigation is

required for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock and red alder.

The common understory plants are western swordfern,

salal, Oregongrape, vine maple, western brackenfern, and

trailing blackberry.

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

index for Douglas fir is 146. On the basis of a 50-year site

curve, it is 112. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 153 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment during periods when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Unsurfaced roads are soft when moist and are subject to

deep rutting during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of soil displacement when the soil is dry.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and displacement.

Seedling establishment is the main concern affecting

timber production. A low content of moisture in the surface

layer during the growing season hinders the survival of

planted and naturally established seedlings.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily

and reforestation by western hemlock occurs periodically.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This unit is suited to homesite development. It has few

limitations. In shallow excavations special retainer walls

may be needed to keep cutbanks from caving. The main

limitation on sites for septic tank absorption fields is a

poor filtering capacity in the substratum. Installing the

absorption field in fill approved by the

health district helps to compensate for this limitation.

This map unit is in capability subclass Ills.

100-Lynden sandy loam, 3 to 8 percent slopes. This

very deep, well drained soil is on outwash terraces. It

formed in loess and volcanic ash over glacial outwash. The

native vegetation is mainly conifers and shrubs. Elevation

is 50 to 300 feet. The average annual precipitation is

about 45 inches, the average annual air temperature is

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

about 170 days.

Typically, the surface layer is dark brown sandy loam 8

inches thick. The subsoil is dark brown sandy loam 10

inches thick. The substratum is variegated sand. The upper

12 inches is dominantly very dark grayish brown, and the

lower part to a depth of 60 inches is dominantly dark

grayish brown. The depth to sand ranges from 14 to 24

inches. In some areas the surface layer is loam. In other

areas the soil has 15 to 25 percent pebbles in the

substratum. In some places the lower part of the subsoil,

the substratum, or both are weakly cemented, mottled, or

both. In other places the combined thickness of the surface

layer and subsoil is 24 to 36 inches or 8 to 14 inches.

Included in this unit are small areas of Hale, Tromp,

and Lynnwood soils and small areas of Lynden soils that

have slopes of more than 8 percent or less than 3

percent. Included areas make up about 10 percent of the

total acreage.

Permeability is moderately rapid in the upper part of the

Lynden soil and very rapid in the substratum. Available

water capacity is moderate. The effective rooting depth is

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

is slight.

This unit is used mainly for hay and pasture, as

cropland, or as woodland. It also is used as a site for

homes.

The main limitation in the areas used for hay and

pasture is the moderate available water capacity.

The main limitations in the areas used as cropland are

the moderate available water capacity and the hazard of

erosion. The principal crops are raspberries, carrots, and

corn silage. Moisture retention can be improved by

mulching, rotating legumes with grain, and leaving residue

on slopes. Drip irrigation is the most suitable method of

applying water for crop production. In summer, irrigation is

required for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock and red alder.

The common understory plants are western swordfern,

salal, Oregongrape, vine maple, western brackenfern, and

trailing blackberry.

On the basis of a 100-year site curve, the mean site
index for Douglas fir is 146. On the basis of a 50-year site

curve, it is 112. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 153 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment during periods when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of soil displacement when the soil is dry.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and displacement.

Seedling establishment is the main concern affecting

timber production. A low content of moisture in the surface

layer during the growing season hinders the survival of

planted and naturally established seedlings. Reforestation

can be accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by western hemlock occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This unit is suited to homesite development. It has few

limitations. In shallow excavations special retainer walls

may be needed to keep cutbanks from caving. The main

limitation on sites for septic tank absorption fields is a

poor filtering capacity in the substratum. Installing the

absorption field in fill approved by the health district helps

to compensate for this limitation.

This map unit is in capability subclass Ille.

101-Lynden-Urban land complex, 0 to 3 percent

slopes. This map unit is on terraces. The native vegetation

is mainly conifers and shrubs. Elevation is 70 to 120 feet.

The average annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 170 days.

This unit is 55 percent Lynden sandy loam and 35

percent Urban land. The components of this unit occur as

areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Hale, Tromp, and

Lynnwood soils and small areas of Lynden soils that have

slopes of more than 3 percent. Included areas make up

about 10 percent of the total acreage.

The Lynden soil is very deep and well drained. It formed

in loess and volcanic ash over glacial outwash. Typically,

the surface layer is dark brown sandy loam 8 inches thick.

The subsoil is dark brown sandy loam 10 inches thick. The

substratum is variegated sand. The upper 12 inches is

dominantly very dark grayish brown, and the lower part to a

depth of 60 inches is dominantly dark grayish brown. The

depth to sand ranges from 14 to 24 inches. In some areas

the surface layer is loam or loamy sand. In other areas the

soil has 15 to 25 percent pebbles in the substratum. In

some places the lower part of the subsoil, the substratum,

or both are weakly cemented, mottled, or both. In other

places the combined thickness of the surface layer and

subsoil is 24 to 36 inches or 8 to 14 inches.

Permeability is moderately rapid in the upper part of the

Lynden soil and very rapid in the lower part. Available

water capacity is moderate. The effective rooting depth is

60 inches. Runoff is very slow, and there is no hazard of

erosion.

The Urban land consists of areas covered by streets,

buildings, parking lots, and other structures that so

obscure the soils that identification of the soil series is not

feasible.

The Lynden soil is used for lawns, gardens, parks, or

vacant lots. This unit is well suited to homesite

development. It has few limitations. In shallow excavations

special retainer walls may be needed to keep cutbanks

from caving. The main limitation on sites for septic tank

absorption fields is a poor filtering capacity in the

substratum. Installing the absorption field in fill approved

by the health district helps to compensate for this limitation.

The Lynden soil is in capability subclass Ills. The

Urban land is in capability subclass VIIIs.

102-Lynnwood sandy loam, 0 to 5 percent

slopes. This very deep, somewhat excessively drained soil

is on eskers and kames. It formed in glaciofluvial deposits

mixed with loess and volcanic ash. The native vegetation is

mainly conifers and shrubs. Elevation is 50 to 300 feet. The

average annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 170 days.

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

leaves, and twigs 2 inches thick. When mixed to a depth

of 5 inches, the surface layer is dark brown sandy loam.

The subsoil is dark yellowish brown loamy sand 14 inches

thick. The substratum to a depth of 60
inches is variegated sand. In some areas the surface layer

is loamy sand or loam. In other areas the soil has 15 to 25

percent pebbles in the substratum or is 14 to 24 inches

deep to loamy sand or sand.

Included in this unit are small areas of Lynden,

Tromp, Everett, and Hale soils and small areas of

Lynnwood soils that have slopes of more than 5 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is rapid in the Lynnwood soil. Available

water capacity is moderate. The effective rooting depth is

60 inches. Runoff is very slow, and there is no hazard of

erosion,

This unit is used mainly for hay and pasture. It also is

used as woodland.

The main limitation in the areas used for hay and

pasture is the moderate available water capacity. Proper

stocking rates, pasture rotation, and restricted grazing

during wet periods help to keep the pasture in good

condition. In summer, irrigation is required for maximum

production.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, and bigleaf maple. The common

understory plants are western brackenfern, salal, western

swordfern, trailing blackberry, and red huckleberry.

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

index for Douglas fir is 151. On the basis of a 50-year site

curve, it is 115. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 159 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment during periods when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Logging roads require

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

construction is not readily available.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of soil displacement when the soil is dry.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and displacement..

Seedling establishment is the main concern affecting

timber production, A low content of moisture in the surface

layer during the growing season hinders the survival of

planted and naturally established seedlings. Reforestation

can be accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

delay the establishment of seedlings. Competing vegetation

can be controlled by mechanical or chemical means.

This map unit has few limitations for homesite

development. In shallow excavations special retainer

walls may be needed to keep cutbanks from caving. The

main limitation on sites for septic tank absorption fields is

a poor filtering capacity in the substratum. Installing the

absorption field in fill approved by the health district

helps to compensate for this limitation,

This map unit is in capability subclass IVs.

103-Lynnwood sandy loam, 5 to 20 percent slopes.

This very deep, somewhat excessively drained soil is on

eskers and kames. It formed in glaciofluvial deposits mixed

with loess and volcanic ash. The native vegetation is mainly

conifers and shrubs. Elevation is 50 to 300 feet. The

average annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 170 days.

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

leaves, and twigs 2 inches thick. When mixed to a depth

of 5 inches, the surface layer is dark brown sandy loam.

The subsoil is dark yellowish brown loamy sand 14 inches

thick. The substratum to a depth of 60 inches is variegated

sand. In some areas the surface layer is loamy sand or

loam, In other areas the soil has 15 to 25 percent pebbles

in the substratum or is 14 to 24 inches deep to loamy

sand or sand.

Included in this unit are small areas of Lynden, Tromp,

Everett, and Hale soils and small areas of Lynnwood soils

that have slopes of more than 20 percent or less than 5

percent. Most of the steeper soils are on side slopes.

Included areas make up about 10 percent of the total

acreage.

Permeability is rapid in the Lynnwood soil. Available

water capacity is moderate. The effective rooting depth is

60 inches. In most areas, runoff is medium and the

hazard of water erosion is moderate, In areas used as

woodland, however, runoff is slow and the hazard of

erosion is slight.

This unit is used mainly for hay and pasture, as

woodland, or as a site for homes.

The main limitations in the areas used for hay and

pasture are the moderate available water capacity and

hazard of water erosion during periods of

reestablishment.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, and bigleaf maple. The common
understory plants are western brackenfern, salal,

western swordfern, trailing blackberry, and red

huckleberry.

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

index for Douglas fir is 151. On the basis of a 50-year site

curve, it is 115. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 159 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment during periods when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of soil displacement when the soil is dry.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and displacement.

Seedling establishment is the main concern affecting

timber production. A low content of moisture in the surface

layer during the growing season hinders the survival of

planted and naturally established seedlings. Reforestation

can be accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

The main limitation affecting homesite development is

the slope. In shallow excavations retainer walls may be

needed to keep cutbanks from caving. The main limitation

on sites for septic tank absorption fields is a poor filtering

capacity in the substratum. Effluent from absorption fields

can surface in downslope areas and create a health

hazard. Installing the absorption field in fill approved by

the health district helps to compensate for this limitation.

The slope affects the installation of septic tank absorption

fields. The absorption lines should be installed on the

contour.

This map unit is in capability subclass IVs.

104 Montborne gravelly loam, 5 to 30 percent slopes.

This moderately deep, moderately well drained soil is on

mountain back slopes and plateaus. It formed in an

admixture of volcanic ash, loess, colluvium, and slope

alluvium over glacial till derived dominantly from phyllite.

The native vegetation is mainly conifers and shrubs.

Elevation is 1,300 to 2,000 feet. The average

annual precipitation is about 70 inches, the average

annual air temperature is about 44 degrees F, and the

average frost-free period is about 120 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. When mixed to a depth of 7

inches, the surface layer is dark yellowish brown gravelly

loam. The subsoil is dark yellowish brown very gravelly

loam 8 inches thick. The substratum is olive brown

extremely gravelly sandy loam 18 inches thick. Dense

glacial till that crushes to very gravelly loam is at a depth

of 33 inches. The depth to dense glacial till ranges from 20

to 40 inches. The dense glacial till is similar to a cemented

pan. In some areas the surface layer is very gravelly loam

or gravelly silt loam. In other areas the soil is 40 to 60

inches deep to phyllite till or bedrock or has less than 35

percent rock fragments in the subsoil.

Included in this unit are small areas of Rinker and

Sorensen soils, soils that are shallow to dense glacial till,

and Montborne soils that have slopes of more than 30

percent or less than 5 percent, Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Montborne soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 20 to 40 inches. Water is perched above the

dense glacial till from December through April. Runoff is

slow, and the hazard of water erosion is slight,

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are vine

maple, western brackenfern, western swordfern, trailing

blackberry, red huckleberry, and longtube twinflower.

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

index for western hemlock is 147. On the basis of a 50-

year site curve, it is 105. The highest average growth rate

in unmanaged, even-aged stands of western hemlock is

232 cubic feet per acre per year, occurring at age 50. On

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

Douglas fir is 146. On the basis of a 50-year site curve, it

is 114. The highest average growth rate in unmanaged,

even-aged stands of Douglas fir is 153 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

occasional snowpack and the muddiness caused by

seasonal wetness, During an average year, the snowpack

limits the use of equipment and restricts access from

January through March. Because most of
the roots are concentrated in the organic mat, loss of this

layer during logging greatly reduces natural fertility and the

available water capacity. Unsurfaced roads are soft and

slippery when wet and are subject to deep rutting during

rainy periods. Rock for road construction is not readily

available. Extra rock is needed to maintain a stable,

uniform road surface. Cut and fill slopes tend to slump

when wet. Following road construction and clearcutting,

road failures and landslides are likely.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep skid trails and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock, Douglas fir, or red alder seedlings. If

seed trees are available, natural reforestation of cutover

areas by western hemlock occurs readily and reforestation

by Douglas fir and red alder occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the dense glacial till, trees

are occasionally subject to windthrow when the soil is wet

and winds are strong.

This map unit is in capability subclass IVe.

105-Montborne gravelly loam, 30 to 60 percent

slopes. This moderately deep, moderately well drained soil

is on mountain back slopes and plateaus. It formed in an

admixture of volcanic ash, loess, colluvium, and slope

alluvium over glacial till derived dominantly from phyllite.

The native vegetation is mainly conifers and shrubs.

Elevation is 1,300 to 2,000 feet. The average annual

precipitation is about 70 inches, the average annual air

temperature is about 44 degrees F, and the average frostfree period is about 120 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. When mixed to a depth of 7

inches, the surface layer is dark yellowish brown gravelly

loam. The subsoil is dark yellowish brown very gravelly

loam 8 inches thick. The substratum is olive brown

extremely gravelly sandy loam 18 inches thick. Dense

glacial till that crushes to

very gravelly loam is at a depth of 33 inches. The depth to

dense glacial till ranges from 20 to 40 inches. The dense

glacial till is similar to a cemented pan. In some areas the

surface layer is very gravelly loam or gravelly silt loam. In

other areas the soil is 40 to 60 inches deep to phyllite till

or bedrock or has less than 35 percent rock fragments in

the subsoil.

Included in this unit are small areas of Rinker and

Sorensen soils, soils that are shallow to dense glacial till,

and Montborne soils that have slopes of more than 60

percent or less than 30 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Montborne soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched above

the dense glacial till from December through April.

Runoff is medium, and the hazard of water erosion is

moderate.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are vine

maple, western brackenfern, western swordfern, trailing

blackberry, red huckleberry, and longtube twinflower.

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

index for western hemlock is 147. On the basis of a 50-

year site curve, it is 105. The highest average growth rate

in unmanaged, even-aged stands of western hemlock is

232 cubic feet per acre per year, occurring at age 50. On

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

Douglas fir is 146. On the basis of a 50-year site curve, it

is 114. The highest average growth rate in unmanaged,

even-aged stands of Douglas fir is 153 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

occasional snowpack, the slope, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and are subject to deep rutting during rainy

periods. Rock for road construction is not readily available.

Extra rock is needed to maintain a stable, uniform road

surface. Cut and fill slopes tend
to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground can reduce the degree of

compaction, puddling, and erosion. Steep yarding paths,

skid trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling establishment and the hazard of windthrow

are the main concerns affecting timber production. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock, Douglas fir, or red alder seedlings. If

seed trees are available, natural reforestation of cutover

areas by western hemlock occurs readily and reforestation

by Douglas fir and red alder occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the dense glacial till, trees

are occasionally subject to windthrow when the soil is wet

and winds are strong.

This map unit is in capability subclass VIle.

106-Montborne-Rinker complex, 30 to 60 percent

slopes. This map unit is on mountain back slopes. The

native vegetation is mainly conifers and shrubs. Elevation

is 1,300 to 2,000 feet. The average annual precipitation is

about 70 inches, the average annual air temperature is

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

about 120 days.

This unit is 60 percent Montborne gravelly loam and 25

percent Rinker very channery silt loam. The components of

this unit occur as areas so intricately intermingled that

mapping them separately was not practical at the selected

scale of mapping.

Included in this unit are small areas of Sorensen soils,

soils that are less than 20 inches deep to dense glacial till

or phyllite, Rock outcrop, stony areas, and Montborne and

Rinker soils that have slopes of more than 60 percent or

less than 30 percent. Included areas make up about 15

percent of the total acreage.

The Montborne soil is moderately deep and moderately

well drained. It formed in an admixture of volcanic ash,

loess, colluvium, and slope alluvium over glacial till derived

dominantly from phyllite. Typically, the

surface is covered with a mat of needles and twigs 4

inches thick. When mixed to a depth of 5 inches, the

surface layer is dark brown gravelly loam. The subsoil is

dark yellowish brown very gravelly loam 15 inches thick.

The substratum is olive brown very gravelly silt loam 8

inches thick. Dense glacial till that crushes to very gravelly

loam is at a depth of 28 inches. The depth to dense glacial

till ranges from 20 to 40 inches. In some areas the surface

layer is gravelly silt loam or very gravelly loam. In other

areas the soil has less than 35 percent rock fragments in

the subsoil.

Permeability is moderate in the upper part of the

Montborne soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched above

the dense glacial till from December through April.

Runoff is medium, and the hazard of water erosion is

moderate.

The Rinker soil is moderately deep and well drained. It

formed in a mixture of volcanic ash, colluvium, and slope

alluvium derived dominantly from phyllite. Typically, the

surface is covered with a mat of needles and twigs 2

inches thick. When mixed to a depth of 7 inches, the

surface layer is dark brown very channery silt loam. The

subsoil is dark yellowish brown very channery silt loam 4

inches thick. The substratum is olive brown extremely

channery loam 19 inches thick. It is underlain by phyllite at

a depth of about 30 inches. The depth to phyllite ranges

from 20 to 40 inches. In some areas the surface layer is

channery silt loam or very channery loam. In other areas

the soil is 40 to 60 inches deep to phyllite.

Permeability is moderate in the Rinker soil. Available

water capacity is high. The effective rooting depth is 20 to

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

erosion is moderate.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are vine

maple, western brackenfern, western swordfern, trailing

blackberry, red huckleberry, and longtube twinflower.

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

index for western hemlock on the Montborne soil is 147.

On the basis of a 50-year site curve, it is 105. The highest

average growth rate in unmanaged, even-aged stands of

western hemlock is 232 cubic feet per acre per year,

occurring at age 50. On the basis of a 100-year site curve,

the mean site index for Douglas fir is 146. On the basis of

a 50-year site curve, it is 114. The highest average growth

rate in unmanaged, even-aged stands of Douglas fir is 153

cubic feet per acre per year, occurring at age 60.
On the basis of a 100-year site curve, the mean site

index for western hemlock on the Rinker soil is 157. On

the basis of a 50-year site curve, it is 110. The highest

average growth rate in unmanaged, even-aged stands of

western hemlock is 249 cubic feet per acre per year,

occurring at age 50. On the basis of a 100-year site curve,

the mean site index for Douglas fir is 146. On the basis of

a 50-year site curve, it is 107. The highest average growth

rate in unmanaged, even-aged stands of Douglas fir is 153

cubic feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, occasional snowpack, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March, When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and are subject to deep rutting during rainy

periods. Phyllite, a poor-quality rock for road construction,

is readily available. Extra rock is needed to maintain a

stable, uniform road surface. Cut and fill slopes tend to

slump when wet. Soil creep is common on this unit.

Equipment and logs on the surface result in a moderate

degree of compaction when the soils are moist and a high

degree of puddling when the soils are wet. Carefully laying

out roads and cable yarding paths, properly timing their

use, and using cable systems that lift logs entirely off the

ground can reduce the degree of compaction, puddling, and

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

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock, Douglas fir, or red alder seedlings. If

seed trees are available, natural reforestation of cutover

areas by western hemlock occurs readily and reforestation

by Douglas fir and red alder occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting

depth is restricted by the dense glacial till or the

bedrock, trees are occasionally subject to windthrow

when the soils are wet and winds are strong.

The Montborne and Rinker soils are in capability

subclass VIIe.

107-Mt. Vernon fine sandy loam, 0 to 2 percent

slopes. This very deep, moderately well drained soil is on

river terraces and on flood plains. It formed in alluvium with

an admixture of volcanic ash. The native vegetation is

mainly conifers and shrubs. Elevation is 10 to 100 feet. The

average annual precipitation is about 35 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 170 days.

Typically, the upper part of the surface layer is dark

brown fine sandy loam 7 inches thick, The lower part is

very dark grayish brown fine sandy loam 6 inches thick.

The underlying material to a depth of 60 inches is dark

grayish brown, olive brown, olive gray, and dark gray,

mottled, stratified fine sandy loam, very fine sandy loam,

and sand. In some areas the surface layer is very fine

sandy loam, In other areas the soil is fine sandy loam in the

underlying material, has sand at a depth of 40 to 60 inches,

or has less than 50 percent base saturation in the surface

layer.

Included in this unit are small areas of Briscot, Puyallup,

Eliza, and Oridia soils, Shalcar soils in depressions,

Riverwash, and Mt, Vernon soils that have slopes of more

than 2 percent. Included areas make up about 15 percent

of the total acreage.

Permeability is moderate in the Mt. Vernon soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 2 to

4 feet from November through April, Runoff is very slow,

and there is no hazard of erosion. In most areas this soil is

subject to occasional, brief periods of flooding from

November through April. Downstream from Lynden,

however, it is subject to frequent, brief periods of flooding

from December through February.

This unit is used mainly for hay and pasture or as

cropland. It also is used as woodland and as a site for

homes.

The main limitations in the areas used for hay and

pasture are the seasonal high water table and the hazard

of flooding, Proper stocking rates, pasture rotation, and

restricted grazing during wet periods help to keep the

pasture in good condition.

The main limitation in the areas used as cropland is the

seasonal high water table. This unit is suited to all crops

commonly grown in the survey area. The principal crops

are peas, sweet corn, beans, small grain, raspberries,

carrots, and corn silage, In summer,
irrigation is required for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western hemlock,

western redcedar, and bigleaf maple. The common

understory plants are western swordfern, western

brackenfern, trailing blackberry, Oregongrape, salal, vine

maple, and salmonberry.

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

index for Douglas fir is estimated to be 174. On the basis

of a 50-year site curve, it is estimated to be 130. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 185 cubic feet per acre per

year, occurring at age 60.

The main limitations affecting timber harvesting are the

hazard of flooding and the muddiness caused by seasonal

wetness. These limit the use of equipment to dry periods.

The use of wheeled and tracked equipment during periods

when the soil is wet causes excessive rutting. Using lowpressure ground equipment can minimize damage to the

soil. Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of soil displacement when the soil is dry.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and displacement.

Seedling establishment is the main concern affecting

timber production. The occasional flooding hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the seasonal high water

table, trees are occasionally subject to windthrow when the

soil is wet and winds are strong.

The main limitations affecting homesite development

are the hazard of flooding and the seasonal high water

table. The wetness can be reduced by building the house

on a pad and by installing drainage tile around footings if

a suitable outlet is available. In shallow excavations

special retainer walls may be needed to keep cutbanks

from caving. The main limitations on sites for septic tank

absorption fields are the hazard of flooding and the

seasonal wetness. Installing the

absorption field in fill approved by the health district helps

to compensate for the wetness. 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 Ilw.

108-Nati loam, 5 to 15 percent slopes. This

moderately deep, well drained soil is on foothill back

slopes and toe slopes. It formed in colluvium and slope

alluvium with an admixture of volcanic ash and glacial till.

The colluvium and alluvium are derived from sandstone and

siltstone. The native vegetation is mainly conifers and

shrubs. Elevation is 100 to 1,600 feet. The average annual

precipitation is about 40 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

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

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

brown loam 3 inches thick. The upper 7 inches of the

subsoil is dark brown loam. The lower 27 inches is dark

yellowish brown loam. Sandstone is at a depth of about 37

inches. The depth to sandstone or siltstone ranges from

20 to 40 inches. In some areas the surface layer is sandy

loam or silt loam. In other areas the soil is 40 to 60 inches

deep over bedrock.

Included in this unit are small areas of Squalicum,

Sehome, Chuckanut, and Comar soils; Bellingham and

Shalcar soils in depressions; and Nati soils that have

slopes of more than 15 percent or less than 5 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is moderate in the Nati soil. Available water

capacity is moderate. The effective rooting depth is 20 to

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

is slight.

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

hay and pasture and as a site for homes. Douglas fir is the

main woodland species. Among the trees of limited extent

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

common understory plants are red huckleberry, salal,

Oregongrape, western swordfern, and western brackenfern.

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

index for Douglas fir is 159. On the basis of a 50-year site

curve, it is 121. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 169 cubic

feet per acre per year, occurring at age 65.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting
during rainy periods. Logging roads require suitable

surfacing for year-round use. Sandstone, a poor-quality

rock for road construction, is readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling. A moderate

reduction in productivity can be expected to result from

unmanaged fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir, western hemlock, or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by western hemlock occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

The main limitation in the areas used for hay and

pasture is the hazard of erosion during periods of

reestablishment. Proper stocking rates, pasture rotation,

and restricted grazing during wet periods help to keep the

pasture in good condition.

The main limitations affecting homesite development

are the depth to bedrock and the slope. The deep cuts

needed to provide essentially level building sites can

expose bedrock. The main limitation on sites for septic

tank absorption fields is the depth to bedrock. This

limitation can be overcome by installing the absorption

field at a shallow depth and by installing absorption lines

that are longer than normal and that are on the contour.

During the rainy season, the effluent from onsite sewage

disposal systems can seep at points downslope.

This map unit is in capability subclass IVs.

109-Nati loam, 15 to 30 percent slopes. This

moderately deep, well drained soil is on foothill back slopes

and toe slopes. It formed in colluvium and slope alluvium

with an admixture of volcanic ash and glacial till. The

colluvium and alluvium are derived from sandstone and

siltstone. The native vegetation is mainly conifers and

shrubs. Elevation is 100 to 1,600 feet. The average annual

precipitation is about 40 inches, the average annual air

temperature is about 47 degrees F, and the average frostfree period is about 160 days.

Typically, the surface is covered with a mat of

needles, leaves, and twigs 4 inches thick. The surface

layer is dark brown loam 8 inches thick. The upper 8

inches of the subsoil is dark yellowish brown loam. The

lower 15 inches is brownish yellow fine sandy loam.

Sandstone is at a depth of about 31 inches. The depth to

sandstone or siltstone ranges from 20 to 40 inches. In

some areas the surface layer is sandy loam or silt loam. In

other areas the soil is 40 to 60 inches deep over bedrock.

Included in this unit are small areas of Squalicum,

Sehome, Chuckanut, and Comar soils; Bellingham and

Shalcar soils in depressions; and Nati soils that have

slopes of more than 30 percent or less than 15 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is moderate in the Nati soil. Available water

capacity also is moderate. The effective rooting depth is 20

to 40 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, and western redcedar. The

common understory plants are red huckleberry, salal,

Oregongrape, western swordfern, and western brackenfern.

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

index for Douglas fir is 159. On the basis of a 50-year site

curve, it is 121. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 169 cubic

feet per acre per year, occurring at age 65.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

surfacing for year-round use. Sandstone, a poor-quality

rock for road construction, is readily available. Cut and fill

slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep skid trails and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be
accomplished by planting Douglas fir, western hemlock, or

red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily

and reforestation by western hemlock occurs periodically.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass IVe.

110-Nati loam, 30 to 60 percent slopes. This

moderately deep, well drained soil is on foothill back slopes

and ridges. It formed in colluvium and slope alluvium with

an admixture of volcanic ash and glacial till. The colluvium

and alluvium are derived from sandstone and siltstone. The

native vegetation is mainly conifers and shrubs. Elevation

is 100 to 1,600 feet. The average annual precipitation is

about 40 inches, the average annual air temperature is

about 47 degrees F, and the average frost-free period is

about 160 days.

Typically, the surface is covered with a mat of needles

and twigs 1 inch thick. The surface layer is dark brown

loam 10 inches thick. The subsoil is dark yellowish brown

loam 28 inches thick. Sandstone is at a depth of about 38

inches. The depth to sandstone or siltstone ranges from 20

to 40 inches. In some areas the surface layer is sandy loam

or silt loam. In other areas the soil is 40 to 60 inches deep

over bedrock.

Included in this unit are small areas of Squalicum,

Sehome, Chuckanut, and Comar soils; Bellingham and

Shalcar soils in depressions; Rock outcrop; and Nati soils

that have slopes of more than 60 percent or less than 30

percent. Included areas make up about 10 percent of the

total acreage.

Permeability is moderate in the Nati soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the

hazard of water erosion is moderate.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, and western redcedar. The

common understory plants are red huckleberry, salal,

Oregongrape, western swordfern, and western brackenfern.

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

index for Douglas fir is 129. On the basis of a 50-year site

curve, it is 98. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 128 cubic

feet per acre per year, occurring at age 70. Areas on

ridgetops that are subject to strong, persistent winds

are less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is

harvested, the slope restricts the use of wheeled and

tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less

extensively. Unsurfaced roads are soft when wet and are

subject to deep rutting during rainy periods. Logging roads

require suitable surfacing for year-round use. Sandstone, a

poor-quality rock for road construction, is readily available.

Cut and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground can reduce the degree of

compaction, puddling, and erosion. Steep yarding paths,

skid trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily and

reforestation by western hemlock occurs periodically.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIle.

111-Neptune very gravelly sandy loam, 0 to 3

percent slopes. This very deep, somewhat excessively

drained soil is on marine ridges, spits, and terraces. In

many areas it is below escarpments. It formed in coastal

beach deposits that contain marine shells. The native

vegetation is mainly conifers and shrubs. Elevation is 5 to

20 feet. The average annual precipitation is about 35

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface layer is black very gravelly sandy

loam 10 inches thick. The upper 17 inches of the

underlying material is very dark brown extremely
gravelly loamy sand. The lower part to a depth of 60

inches is variegated extremely gravelly sand or extremely

gravelly coarse sand. In some areas the surface layer is

very gravelly loam or gravelly sandy loam. In other areas

the soil has a partially cemented substratum.

Included in this unit are small areas of Hovde soils,

deposits of sand, and bodies of water. Included areas

make up about 10 percent of the total acreage.

Permeability is very rapid in the Neptune soil. Available

water capacity is low. The effective rooting depth is 60

inches. Runoff is very slow, and there is no hazard of

erosion. The soil is subject to rare flooding from tidal

inundation.

This unit is used as woodland or as a site for homes

and industry. It also is used for recreation.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder and bigleaf maple. The

common understory plants are salal, Oregongrape,

western swordfern, and vine maple.

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

index for Douglas fir is estimated to be 132. On the basis

of a 50-year site curve, it is estimated to be 100. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 133 cubic feet per acre per

year, occurring at age 70.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted

on this unit. Generally, the surface layer is loose when dry.

As a result, the use of wheeled and tracked equipment is

limited. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Logging roads require suitable surfacing for year-round

use. Rounded pebbles and cobbles for road construction

are readily available.

Equipment and logs on the surface result in a

moderate degree of soil displacement when the soil is

dry. Carefully laying out roads and skid trails, properly

timing their use, and using low-pressure ground

equipment can reduce the degree of displacement.

Seedling mortality is the main concern affecting timber

production. A high soil temperature and a low content of

moisture in the soil during the growing season cause a

high rate of seedling mortality. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

The main limitation affecting homesite development

is the hazard of flooding. In shallow excavations special

retainer walls may be needed to keep cutbanks from

caving. The main limitation on sites for septic tank

absorption fields is a poor filtering capacity. Installing the

absorption field in fill approved by the health district helps

to compensate for this limitation.

This map unit is in capability subclass IVs.

112-Oakes very gravelly loam, 8 to 30 percent

slopes. This very deep, well drained soil is on colluvial

side slopes on mountains. It formed in volcanic ash,

colluvium, and slope alluvium derived from glacial drift.

The native vegetation is mainly conifers and shrubs.

Elevation is 1,000 to 2,500 feet. The average annual

precipitation is about 75 inches, the average annual air

temperature is about 44 degrees F, and the average frostfree period is about 120 days.

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

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

brown very gravelly loam 4 inches thick. The upper 12

inches of the subsoil is dark brown very gravelly loam. The

lower 8 inches is dark brown extremely gravelly sandy

loam. The substratum to a depth of 60 inches is olive brown

extremely cobbly fine sandy loam. In some areas the

surface layer is very gravelly sandy loam or gravelly loam.

In other areas the soil has a substratum of loamy sand, is

40 to 60 inches deep to dense glacial till or bedrock, is

moderately well drained, or has 15 to 35 percent total rock

fragments or more than 15 percent phyllite rock fragments

in the solum or substratum.

Included in this unit are small areas of Cupples,

Sorensen, Montborne, Rinker, and Welcome soils, stony

areas, slump areas, and Oakes soils that have slopes of

more than 30 percent or less than 8 percent. Included

areas make up about 15 percent of the total acreage.

Permeability is moderate in the Oakes soil, Available

water capacity is high. The effective rooting depth is 60

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

slight.

This unit is used as woodland. Douglas fir and western

hemlock are the main woodland species. Among the trees

of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are salal,

Oregongrape, western swordfern, western brackenfern, red

huckleberry, vine maple, trailing blackberry, and tall blue

huckleberry.

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

index is 152 for Douglas fir and 148 for western hemlock.

On the basis of a 50-year site curve, it is 117 for Douglas

fir and 105 for western hemlock. The highest average

growth rate in unmanaged, even-aged stands of Douglas

fir is 161 cubic feet per acre per
year, occurring at age 60. For western hemlock, it is 234

cubic feet per acre per year, occurring at age 50.

The main limitation affecting timber harvesting is

occasional snowpack. During an average year, the

snowpack limits the use of equipment and restricts access

from January through March. Unsurfaced roads are soft

when wet and are subject to deep rutting during rainy

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

available. Cut and fill slopes tend to slump when wet. Steep

yarding paths, skid trails, and firebreaks are subject to rilling

and gullying unless adequate water bars are provided or a

protective plant cover is established. A moderate reduction

in productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than in

other areas of this unit. Reforestation can be accomplished

by planting Douglas fir, western hemlock, or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by western hemlock occurs readily and

reforestation by Douglas fir and red alder occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

delay the establishment of seedlings. Competing vegetation

can be controlled by mechanical or chemical means.

This map unit is in capability subclass IVe.

113-Oakes very gravelly loam, 30 to 60 percent

slopes. This very deep, well drained soil is on colluvial

side slopes on mountains. It formed in volcanic ash,

colluvium, and slope alluvium derived from glacial drift.

The native vegetation is mainly conifers and shrubs.

Elevation is 1,000 to 2,500 feet. The average annual

precipitation is about 75 inches, the average annual air

temperature is about 44 degrees F, and the average frostfree period is about 120 days.

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

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

brown very gravelly loam 5 inches thick. The upper 12

inches of the subsoil is dark brown very gravelly loam. The

lower 12 inches is dark brown extremely gravelly sandy

loam. The substratum to a depth of 60 inches is olive

brown extremely cobbly fine sandy. loam. In some areas

the surface layer is very gravelly sandy loam or gravelly

loam. In other areas the soil has a substratum of loamy

sand, is 40 to 60 inches deep to dense glacial till or

bedrock, is moderately well drained, or has 15 to 35

percent total rock fragments or more than 15 percent

phyllite rock fragments in the solum or substratum.

Included in this unit are small areas of Cupples,

Sorensen, Montborne, Rinker, and Welcome soils, stony

areas, slump areas, and Oakes soils that have slopes of

more than 60 percent or less than 30 percent. Included

areas make up about 15 percent of the total acreage.

Permeability is moderate in the Oakes soil. Available

water capacity is high. The effective rooting depth is 60

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

is moderate.

This unit is used as woodland. Douglas fir and western

hemlock are the main woodland species. Among the trees

of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are salal,

Oregongrape, western swordfern, western brackenfern, red

huckleberry, vine maple, trailing blackberry, and tall blue

huckleberry.

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

index is 152 for Douglas fir and 148 for western hemlock.

On the basis of a 50-year site curve, it is 117 for Douglas

fir and 105 for western hemlock. The highest average

growth rate in unmanaged, even-aged stands of Douglas fir

is 161 cubic feet per acre per year, occurring at age 60.

For western hemlock, it is 234 cubic feet per acre per year,

occurring at age 50. Areas on ridgetops that are subject to

strong, persistent winds are less productive than the other

areas of this unit.

The main limitations affecting timber harvesting are the

slope, occasional snowpack, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use. Rock

for road construction is not readily available. Cut and fill

slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established. A

moderate reduction in productivity can be expected to

result from unmanaged fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher
on ridgetops that are subject to strong, persistent winds

than in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir, western hemlock, or

red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock occurs

readily and reforestation by Douglas fir and red alder occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

delay the establishment

of seedlings. Competing vegetation can be controlled by

mechanical or chemical means.

This map unit is in capability subclass VIle.

114-Oakes very gravelly loam, 60 to 80 percent

slopes. This very deep, well drained soil is on colluvial side

slopes and canyon sides on mountains. It formed in

volcanic ash, colluvium, and slope alluvium derived from

glacial drift. The native vegetation is mainly conifers and

shrubs. Elevation is 1,500 to 2,500 feet. The average

annual precipitation is about 75 inches, the average annual

air temperature is about 44 degrees F, and the average

frost-free period is about 120 days.

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

leaves, and twigs 4 inches thick. When mixed to a depth of

8 inches, the surface layer is dark brown very gravelly

loam. The upper 10 inches of the subsoil is dark brown

very gravelly sandy loam. The lower 16 inches is dark

brown extremely gravelly sandy loam. The substratum to a

depth of 60 inches is dark grayish brown extremely

gravelly sandy loam. In some areas the surface layer is

very gravelly sandy loam. In other areas the soil has an

extremely cobbly or extremely stony substratum, is 40 to

60 inches deep to dense glacial till or bedrock, is

moderately well drained, or has 15 to 35 percent total rock

fragments in the solum or substratum.

Included in this unit are small areas of Cupples,

Sorensen, Montborne, and Welcome soils, stony areas,

Rock outcrop, and Oakes soils that have slopes of less

than 60 percent. Included areas make up about 15 percent

of the total acreage.

Permeability is moderate in the Oakes soil. Available

water capacity is high. The effective rooting depth is 60

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

severe.

This unit is used as woodland. Douglas fir and western

hemlock are the main woodland species. Among the trees

of limited extent. are western redcedar, red alder, and

bigleaf maple. The common understory plants are salal,

Oregongrape, western swordfern, western brackenfern, red

huckleberry, vine maple, trailing blackberry, and tall blue

huckleberry.

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

index is 127 for Douglas fir and is estimated to be 140 for

western hemlock. On the basis of a 50-year site curve, it

is 94 for Douglas fir and is estimated to be 100 for western

hemlock. The highest average growth rate in unmanaged,

even-aged stands of Douglas fir is 125 cubic feet per acre

per year, occurring at age 70. For western hemlock, it is

about 218 cubic feet per acre per year, occurring at age

60. Areas on ridgetops that are subject to strong,

persistent winds are less productive than the other areas

of this unit.

The main limitations affecting timber harvesting are the

slope, occasional snowpack, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. These systems generally are used on this

unit. Unsurfaced roads are soft when wet and are subject

to deep rutting during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit. Locating roads on midslopes

requires extensive cutting and filling, which remove land

from production.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established. A

moderate reduction in productivity can be expected to result

from unmanaged fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir, western hemlock, or

red alder seedlings. Because of the slope, planting

seedlings is difficult. If seed trees are available, natural

reforestation of cutover areas by western hemlock

occurs readily and reforestation by Douglas fir and red

alder occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

This map unit is in capability subclass VIIe.
115-Oridia silt loam, drained, 0 to 2 percent slopes.

This very deep, poorly drained soil is on flood plains. It has

been artificially drained. It formed in alluvium. The native

vegetation is mainly trees and shrubs. Elevation is 20 to 300

feet. The average annual precipitation is about 45 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free period is about 170 days.

Typically, the surface layer is dark grayish brown silt

loam 10 inches thick. The upper 22 inches of the underlying

material is dark grayish brown, mottled silt loam and very

fine sandy loam. The lower part to a depth of 60 inches is

gray and grayish brown, mottled very fine sandy loam. In

some areas the surface layer is very fine sandy loam. In

other areas the soil has a dark brown surface layer, is

sandy loam or loam in the lower part of the underlying

material, has thin strata of sand, or has 18 to 25 percent

clay in the upper part of the underlying material.

Included in this unit are small areas of Shalcar soils,

which are in depressions and are subject to ponding, and

small areas of Mt. Vernon soils and undrained Oridia soils.

Also included are small bodies of water. Included areas

make up about 10 percent of the total acreage.

Permeability is moderate in the Oridia soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1 to

3 feet from November through April. Runoff usually is very

slow, but the soil may be ponded during the winter. There

is no hazard of erosion. In most areas this soil is subject to

occasional, brief periods of flooding from November

through April. Downstream from Lynden, however, it is

subject to frequent, brief periods of flooding from

December through February.

This unit is used mainly for hay and. pasture or as

cropland. The included undrained Oridia soils are used as

woodland.

The main limitations in the areas used for hay and

pasture are the high water table and the hazard of flooding.

Proper stocking rates, pasture rotation, and restricted

grazing during wet periods help to keep the pasture in good

condition. Grazing when the soil is wet results in compaction

of the surface layer and poor tilth. In areas where the

drainage system is not maintained or in areas that do not

have drainage, the water table limits the use of this unit to

grasses and shallow-rooted legumes. The wetness limits

the choice of plants and the period of cutting or grazing and

increases the risk of winterkill.

The main limitations in the areas used as cropland are

the high water table and the hazard of flooding. This soil is

well suited to most-crops commonly grown in the

survey area if adequate drainage systems are maintained.

These crops are peas, sweet corn, beans, and small grain.

Returning all crop residue to the soil and including

grasses, legumes, or grass-legume mixtures in the

cropping sequence help to maintain fertility and tilth.

During the growing season, the water table is artificially

lowered to a depth of about 3 to 5 feet. Tile drains and

field ditches should be maintained. They permit fieldwork

to be conducted earlier in the spring and increase the

yields of perennial crops. In summer, irrigation is required

for maximum production.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar and black

cottonwood. The common understory plants are

salmonberry, Douglas spirea, rose, stinging nettle, and

sedges.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitations affecting timber harvesting are the

occasional flooding and the muddiness caused by seasonal

wetness. The use of wheeled and tracked equipment

during periods when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and are subject to deep rutting during rainy periods. Rock

for road construction is not readily available. Extra rock is

needed to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of, compaction and puddling.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table and the flooding hinder

root respiration and thus result in a low seedling survival

rate. Reforestation can be accomplished by planting red

alder or western redcedar seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the high water table, trees are frequently subject to

windthrow when the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the high water table and the hazard
of flooding. The wetness can be reduced by building the

house on a pad and by installing drainage tile around

footings if a suitable outlet is available. The main limitations

on sites for septic tank absorption fields are the seasonal

high water table and the hazard of flooding. The seasonal

high water table increases the likelihood that the absorption

field will fail. Installing absorption lines that are longer than

normal helps to overcome this limitation.

This map unit is in capability subclass Ilw.

116-Pangborn muck, drained, 0 to 2 percent slopes.

This very deep, very poorly drained soil is in depressions

on outwash terraces and on some till plains and stream

terraces. It has been artificially drained. It formed in

herbaceous and woody organic deposits. The native

vegetation is mainly shrubs, forbs, and trees. Elevation is

near sea level to 600 feet above sea level. The average

annual precipitation is about 45 inches, the average annual

air temperature is about 50 degrees F, and the average

frost-free period is about 170 days.

Typically, the surface layer is dark reddish brown muck

15 inches thick. The underlying material to a depth of 60

inches is very dark brown and dark reddish brown muck. In

some areas the soil is hemic material.

Included in this unit are small areas of Shalcar,

Bellingham, Snohomish, Puget, Fishtrap, and Hale soils,

ponded areas, and Pangborn soils that have not been

drained or have slopes of more than 2 percent. Included

areas make up about 10 percent of the total acreage..

Permeability is moderate in the Pangborn soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1.5 to

2.5 feet from October through May. Runoff usually is very

slow, but the soil may be ponded during the winter. There is

no hazard of erosion.

This unit is used mainly for hay and pasture or as

cropland (fig. 5). The included undrained Pangborn soils are

used as woodland.

The main limitation in the areas used for hay and

pasture is the high water table. Proper stocking rates,

pasture rotation, and restricted grazing during wet periods

help to keep the pasture in good condition. The wetness

limits the choice of plants and the period of cutting or

grazing and increases the risk of winterkill. Grazing when

the soil is wet results in compaction of the surface layer

and poor tilth.

The main limitations in the areas used as cropland are

the high water table and the soil acidity. This soil is well

suited to most crops commonly grown in the survey area if

adequate drainage systems are maintained. The principal

crops are potatoes, blueberries, and corn silage. Tile drains

and field ditches should be

maintained. They permit fieldwork to be conducted earlier in

the spring and increase the yields. During the growing

season, the water table is artificially lowered to a depth of

about 3 to 5 feet. Subsidence is minimized if the water

table is maintained directly below the root zone during the

growing season and then allowed to return to the surface

during the winter. Using regulating structures in open

ditches as a means of subirrigation reduces the extent of

subsidence. In summer, irrigation is required for maximum

production. Soil acidity can be reduced by adding lime.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, lodgepole pine, and Sitka spruce. The common

understory plants are willow, Douglas spirea,

salmonberry, stinging nettle, and sedges.

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

index for red alder is estimated to be 85. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 92 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The high water

table limits the use of equipment to dry periods.

Unsurfaced roads are soft and slippery when wet and

may be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is needed

to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the high water table and the low strength.

The wetness can be reduced by building the house on a

pad and by installing drainage tile around footings if a

suitable outlet is available. If buildings are
Figure 5.-Open ditch drainage in a pastured area of Pangborn muck, drained, 0 to 2 percent slopes.

constructed on this soil, the muck should be excavated or

the buildings should be constructed on piles anchored in

the mineral soil. The design of buildings and roads can

offset the limited ability of the soil to support a load. The

high water table is a limitation on sites for septic tank

absorption fields. Installing the absorption field in fill

approved by the health district helps to compensate for

this limitation.

This map unit is in capability subclass Ilw.

117-Pickett-Rock outcrop complex, 5 to 30 percent

slopes. This map unit is on glacially modified foot slopes,

back slopes, and ridgetops. The native vegetation is

mainly conifers and shrubs. Elevation is sea level to

1,700 feet above sea level. The average annual

precipitation is about 35 inches, the average annual air

temperature is about 49 degrees F, and the average

frost-free period is about 180 days.

This unit is 65 percent Pickett very gravelly silt loam
and 20 percent Rock outcrop. The components of this unit

occur as areas so intricately intermingled that mapping

them separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Everett,

Kickerville, Nati, and Squalicum soils, soils that are less

than 20 inches deep over bedrock, stony areas, poorly

drained mineral soils in depressions, and Pickett soils that

have slopes of more than 30 percent or less than 5

percent. Included areas make up about 15 percent of the

total acreage.

The Pickett soil is moderately deep and well drained. It

formed in colluvium derived from graywacke and argillite

with an admixture of volcanic ash. Typically, the surface is

covered with a mat of needles, leaves, and twigs 1 inch

thick. When mixed to a depth of 7 inches, the surface layer

is dark brown very gravelly silt loam. The subsoil is dark

brown very gravelly silt loam 16 inches thick. Argillite is at

a depth of about 23 inches. The depth to argillite or

graywacke ranges from 20 to 40 inches. In some areas the

surface layer is gravelly silt loam. In other areas the soil is

40 to 60 inches deep over bedrock.

Permeability is moderate in the Pickett soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is slow, and the hazard of water

erosion is slight.

Typically, the Rock outcrop is argillite or graywacke. It is

hard and generally unweathered. It occurs as steep cliffs

and irregular formations.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

red alder, western hemlock, and western redcedar. The

common understory plants are Oregongrape, salal, western

swordfern, creambush oceanspray, and red huckleberry.

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

index for Douglas fir is estimated to be 115. On the basis

of a 50-year site curve, it is estimated to be 88. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 106 cubic feet per acre per

year, occurring at age 60. Yields are reduced by the

extent of the Rock outcrop. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitation affecting timber harvesting is the

Rock outcrop. The pattern of the Rock outcrop on the

landscape results in a discontinuous slope, which hinders

the use of cable yarding systems. The trees can break if

they are felled on the Rock outcrop. Unsurfaced roads are

soft when wet and are subject to deep rutting during rainy

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

is readily available. Cut and fill slopes tend to slump

when wet.

Seedling establishment is the main concern affecting

timber production. A high soil temperature and a low

content of moisture in the soil during the growing season

cause a high rate of seedling mortality. The seedling

mortality rate is higher on ridgetops that are subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily.

The Rock outcrop prevents the even distribution of

reforestation. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the

bedrock, trees are occasionally subject to windthrow when

the Pickett soil is wet and winds are strong.

The Pickett soil is in capability subclass IVe. The

Rock outcrop is in capability subclass VIlls.

118-Pickett-Rock outcrop complex, 30 to 60

percent slopes. This map unit is on glacially modified foot

slopes, back slopes, and ridgetops. The native vegetation

is mainly conifers and shrubs. Elevation is sea level to

1,700 feet above sea level. The average annual

precipitation is about 35 inches, the average annual air

temperature is about 49 degrees F, and the average frostfree period is about 180 days.

This unit is 60 percent Pickett very gravelly silt loam and

25 percent Rock outcrop. The components of this unit

occur as areas so intricately intermingled that mapping

them separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Nat! and Sehome

soils, soils that are less than 20 inches deep over bedrock,

stony areas, poorly drained mineral soils in depressions,

and Pickett soils that have slopes of more than 60 percent

or less than 30 percent. Included areas make up about 15

percent of the total acreage.

The Pickett soil is moderately deep and well drained. It

formed in colluvium derived from graywacke and argillite

with an admixture of volcanic ash. Typically, the surface is

covered with a mat of needles, leaves, and twigs 2 inches

thick. When mixed to a depth of 7 inches, the surface layer

is dark brown very gravelly silt loam. The subsoil is brown

very gravelly silt loam 22 inches thick. Graywacke is at a

depth of about 29 inches. The depth to argillite or

graywacke ranges from 20 to 40 inches. In some areas the

surface layer is gravelly silt loam. In other areas the soil is

40 to 60 inches deep over bedrock.
Permeability is moderate in the Pickett soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the

hazard of water erosion is moderate.

Typically, the Rock outcrop is argillite or graywacke. It is

hard and generally unweathered. It occurs as steep cliffs

and irregular formations.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are red

alder, western hemlock, and western redcedar. The

common understory plants are Oregongrape, salal, western

swordfern, creambush oceanspray, and red huckleberry.

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

index for Douglas fir is estimated to be 115. On the basis

of a 50-year site curve, it is estimated to be 88. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 106 cubic feet per acre per

year, occurring at age 60. Yields are reduced by the

extent of the Rock outcrop. Areas on ridgetops that are

subject to strong, persistent winds are less productive

than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, the Rock outcrop, and the hazard of erosion. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

The pattern of the Rock outcrop on the landscape results in

a discontinuous slope, which hinders the use of cable

yarding systems. The trees can break if they are felled on

the Rock outcrop. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Logging

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

road construction is readily available. Cut and fill slopes

tend to slump when wet. Following road construction and

clearcutting, road. failures and landslides are likely. Soil

creep is common on this unit.

Because of the Rock outcrop, yarding and skidding

paths converge. This convergence results in compaction of

the underlying soil. Carefully laying out roads and cable

yarding paths, properly timing their use, and using cable

systems that lift logs entirely off the ground reduce the

hazard of erosion. Steep yarding paths, skid trails, and

firebreaks are subject to rifling .and gullying unless

adequate water bars are provided , or a protective plant

cover is established.

Seedling establishment is the main concern affecting

timber production. A high soil temperature and a low

content of moisture in the soil during the growing season

cause a high rate of seedling mortality. The seedling

mortality rate is higher on ridgetops that are subject to

strong, persistent winds than in other areas of this unit.

Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. The Rock outcrop prevents the even

distribution of reforestation. When openings are made in

the canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the bedrock, trees are occasionally subject

to windthrow when the Pickett soil is wet and winds are

strong.

The Pickett soil is in capability subclass VIle. The

Rock outcrop is in capability subclass Vllls.

119-Pilchuck loamy fine sand, 0 to 3 percent slopes.

This very deep, somewhat excessively drained soil is on

flood plains. It formed in alluvium. The native vegetation is

mainly trees and shrubs. Elevation is 50 to 400 feet. The

average annual precipitation is about 50 inches, the

average annual air temperature is about 49 degrees F, and

the average frost-free period is about 170 days.

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

leaves, and twigs 2 inches thick. When mixed to a depth

of 6 inches, the surface layer is black loamy fine sand.

The upper 38 inches of the underlying material is very

dark grayish brown, dark brown, and very dark brown fine

sand and loamy fine sand. The lower part to a depth of 60

inches is black sand. In some areas the surface layer is

loamy sand, sand, or sandy loam. In other areas the soil

has a gravelly substratum or has a substratum with strata

of sandy loam.

Included in this unit are small areas of Puyallup and

Snoqualmie soils, small areas of organic soils and Briscot

soils in depressions, Riverwash, and soils that are similar to

the Pilchuck soil but have a seasonal high water table at a

depth of 48 to 60 inches. Included areas make up about 10

percent of the total acreage.

Permeability is rapid in the Pilchuck soil. Available water

capacity is low. The effective rooting depth is 60 inches.

Runoff is very slow, and the hazard of water erosion is

severe because of flooding and channeling. A seasonal

high water table fluctuates in depth from 2 to 4 feet from

November through April. This soil is subject to frequent,

brief periods of flooding from November through April

during periods of snowmelt and rainfall.

This unit is used mainly as woodland. Douglas fir is the

main woodland species. Among the trees of limited extent

are red alder, western hemlock, western redcedar, bigleaf

maple, and black cottonwood. The common understory

plants are vine maple, western swordfern, salmonberry,

common snowberry, false Solomons seal, and western

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

index for Douglas fir is estimated to be 152. On the basis

of a 50-year site curve, it is estimated to be 114. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 161 cubic feet per acre per

year, occurring at age 60.

The main limitation affecting timber harvesting is the

flooding. This limits the use of equipment to dry periods.

Generally, the surface layer is loose when dry. As a result,

the use of wheeled and tracked equipment is limited.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is not readily available.

Equipment and logs on the surface can easily result in

soil displacement when the soil is dry. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

displacement. A reduction in productivity can be expected

to result from unmanaged fires in undisturbed areas.

Seedling mortality and establishment are the main

concerns affecting timber production. The seedling survival

rate is reduced by droughtiness in the surface layer and

may be low in areas where flooding occurs. Reforestation

can be accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder, bigleaf maple, and black

cottonwood occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This map unit is in capability subclass IVw.

120-Pits, gravel. This map unit is on glaciomarine

drift plains, outwash terraces, mountains, and foothills. It

consists of areas excavated for gravel, sand, and hard

rock. Areas are irregular in shape and are 5 to 90 acres in

size.

Included in this unit are small areas of soils that have

not been excavated, areas that have been partially filled as

dump sites, areas that have no gravel or hard rock, and

small ponds where material has been excavated below the

water table.

A seasonal high water table fluctuates in depth from 0 to

more than 60 inches from November through April.

Permeability, the effective rooting depth, available water

capacity, surface runoff, and the hazard of erosion vary

widely. They are dependent on the amount of disturbance

of the soil. Runoff is ponded to very rapid, and the hazard of

water erosion ranges from none to severe.

This unit is used mainly for excavation of gravel or

rock deposits. It also is used for wildlife habitat. This unit

varies too much to be rated for potential uses. Onsite

evaluation is needed. The main limitation in areas used as

woodland, pasture, or cropland is a lack of soil fertility.

This map unit is in capability subclass Vllls.

121-Potchub loam, 8 to 30 percent slopes. This

moderately deep, moderately well drained soil is on high

mountain back slopes and ridges. It formed in an

admixture of volcanic ash, loess, and colluvium over

glacial till. The native vegetation is mainly conifers and

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

annual precipitation is about 90 inches, the average annual

air temperature is about 42 degrees F, and the average

frost-free period is about 95 days.

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

leaves, and twigs 10 inches thick. When mixed to a depth

of 7 inches, the surface layer is loam. The upper 8 inches

of the subsoil is organic stained, strong brown loam. The

lower 17 inches is strong brown and yellowish red gravelly

loam. Dense glacial till that crushes to extremely gravelly

loam is at a depth of 32 inches. The depth to dense glacial

till ranges from 20 to 40 inches. The dense glacial till is

similar to a cemented pan. In some areas the surface layer

is silt loam or gravelly loam. In other areas the soil has a

very gravelly subsoil, has a less developed subsoil, is 40 to

60 inches deep to dense glacial till or bedrock, or has less

than 6 percent organic carbon in the upper part of the

subsoil.

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

Clendenen, and Gallup soils, soils that are similar to the

Potchub soil but are underlain by soft sandstone at a depth

of 20 to 40 inches, poorly drained mineral and organic soils

in depressions, and Potchub soils that have slopes of more

than 30 percent or less than 8 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Potchub soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 20 to 40 inches. Water is perched above the

dense glacial till from November through May. Runoff is

slow, and the hazard of water erosion is slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are mountain hemlock and western

redcedar. The common understory plants are red

huckleberry, blueleaved huckleberry, bunchberry dogwood,

deer fern, and longtube twinflower.

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

index for western hemlock is 101. On the basis of a 50-
year site curve, it is 72. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 144

cubic feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit. Estimates

of the site index or growth rate for Pacific silver fir have not

been made.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal

wetness. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. The use of wheeled and tracked equipment

when the soil is wet causes excessive rutting. Using lowpressure ground equipment can minimize damage to the

soil. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep skid trails and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock,

mountain hemlock, and Pacific silver fir occurs periodically.

Because the rooting depth is restricted by the dense glacial

till, trees are occasionally subject to windthrow when the

soil is wet and winds are strong.

This map unit is in capability subclass VIe.

122-Potchub loam, 30 to 60 percent slopes. This

moderately deep, moderately well drained soil is on high

mountain back slopes and ridges. It formed in an

admixture of volcanic ash, loess, and colluvium over

glacial till. The native vegetation is mainly conifers and

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

annual precipitation is about 90 inches, the average

annual air temperature is about 42 degrees F, and the

average frost-free period is about 95 days.

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

leaves, and twigs 8 inches thick. When mixed to a depth of

7 inches, the surface layer is strong brown loam. The

upper 22 inches of the subsoil is strong brown gravelly

loam and gravelly sandy loam. The lower 10 inches is

brown gravelly sandy loam. Dense glacial till is at a depth

of about 39 inches. The depth to dense glacial till ranges

from 20 to 40 inches. The dense glacial till is similar to a

cemented pan. In some areas the surface layer is silt loam

or gravelly loam. In other areas the soil has a very gravelly

subsoil, has a less developed subsoil, is 40 to 60 inches

deep to dense glacial till or bedrock, or has less than 6

percent organic carbon in the upper part of the subsoil.

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

Clendenen, and Gallup soils, soils that are similar to the

Potchub soil but are underlain by soft sandstone at a'

depth of 20 to 40 inches, Rock outcrop, and Potchub soils

that have slopes of more than 60 percent or less than 30

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the

Potchub soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from November through

May. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among

the trees of limited extent are mountain hemlock and

western redcedar. The common understory plants are red

huckleberry, blueleaved huckleberry, bunchberry dogwood,

deer fern, and longtube twinflower.

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

index for western hemlock is 101. On the basis of a 50-

year site curve, it is 72. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 144

cubic feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit. Estimates

of the site index or growth rate for Pacific silver fir have not

been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are
concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and are subject to deep rutting during rainy

periods. Rock for road construction is not readily available.

Cut and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground can reduce the degree of

compaction, puddling, and erosion. Steep yarding paths,

skid trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock,

mountain hemlock, and Pacific silver fir occurs periodically.

Because the rooting depth is restricted by the dense glacial

till, trees are occasionally subject to windthrow when the

soil is wet and winds are strong.

This map unit is in capability subclass VIle.

123-Puget silt loam, drained, 0 to 2 percent slopes.

This very deep, poorly drained soil is on flood plains. It has

been artificially drained. It formed in alluvium. The native

vegetation is mainly trees and shrubs. Elevation is 20 to

300 feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface layer is dark grayish brown, mottled

silt loam 9 inches thick. The upper 7 inches of the

underlying material is grayish brown, mottled silt loam. The

lower part to a depth of 60 inches is gray and dark gray,

mottled silt loam. In some areas the surface layer is silty

clay loam. In other areas the soil has a dark brown surface

layer; is not mottled in the surface layer; is sandy loam,

loamy sand, or sand in the lower part of the underlying

material; has 10 to 18 percent clay in the upper part of the

underlying material;

or has thin strata of sandy material in the underlying

material.

Included in this unit are small areas of Shalcar soils,

which are in depressions and are subject to ponding, and

small areas of Mt. Vernon soils and undrained Puget soils.

Also included are small bodies of water. Included areas

make up about 10 percent of the total acreage.

Permeability is moderately slow in the Puget soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 1 to 3 feet from November through May. Runoff

usually is very slow, but the soil may be ponded during the

winter. There is no hazard of erosion. In most areas this

soil is subject to occasional, brief periods of flooding from

November through April. Downstream from Lynden,

however, it is subject to frequent, brief periods of flooding

from December through February.

This unit is used mainly for hay and pasture or as

cropland. The included undrained Puget soils are used as

woodland.

The main limitations in the areas used for hay and

pasture are the high water table, the hazard of flooding,

and the moderately slow permeability. Proper stocking

rates, pasture rotation, and restricted grazing during wet

periods help to keep the pasture in good condition. Grazing

when the soil is wet results in compaction of the surface

layer and poor tilth. In areas where the drainage system is

not maintained or in areas that do not have drainage, the

water table limits the use of this unit to grasses. The

wetness limits the choice of plants and the period of cutting

or grazing and increases the risk of winterkill.

The main limitations in the areas used as cropland are

the high water table, the hazard of flooding, and the

moderately slow permeability. This soil is well suited to

most crops commonly grown in the survey area if adequate

drainage systems are maintained. These crops are peas,

sweet corn, beans, and small grain. Returning all crop

residue to the soil and including grasses, legumes, or

grass-legume mixtures in the cropping sequence help to

maintain fertility and tilth. During the growing season, the

water table is artificially lowered to a depth of about 3 to 5

feet. Tile drains and field ditches should be maintained.

They permit fieldwork to be conducted earlier in the spring

and increase the yields of perennial crops. Drainage tiles

should be closely spaced because of the moderately slow

permeability. In summer, irrigation is required for maximum

production.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar and black

cottonwood. The common understory plants are
salmonberry, Douglas spirea, rose, stinging nettle, and

sedges.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitations affecting timber harvesting are the

occasional flooding and the muddiness caused by seasonal

wetness. The use of wheeled and tracked equipment during

periods when the soil is wet causes excessive rutting.

Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and are subject to deep rutting during rainy periods. Rock

for road construction is not readily available. Extra rock is

needed to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table and the flooding hinder

root respiration and thus result in a low seedling survival

rate. Reforestation can be accomplished by planting red

alder or western redcedar seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the high water table and the hazard of

flooding. The wetness can be reduced by building the

house on a pad and by installing drainage tile around

footings if a suitable outlet is available. The main

limitations on sites for septic tank absorption fields are the

restricted permeability, the high water table, and the hazard

of flooding. Installing absorption lines that are longer than

normal helps to overcome these limitations.

This map unit is in capability subclass llw.

124-Puyallup fine sandy loam, 0 to 2 percent slopes.

This very deep, well drained soil is on low river terraces

and on flood plains. It formed in alluvium. The native

vegetation is mainly conifers and shrubs. Elevation is 50 to

300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 180 days.

Typically, the upper part of the surface layer is very dark

grayish brown fine sandy loam 6 inches thick. The lower

part is very dark grayish brown loam and fine sandy loam

13 inches thick. The underlying material to a depth of 60

inches is very dark grayish brown sand. The depth to

loamy sand or sand ranges from 15 to 30 inches. In some

areas the surface layer is loam or silt loam. In other areas

the soil has less than 50 percent base saturation in the

surface layer, has a substratum stratified with sandy loam,

or has a gravelly substratum.

Included in this unit are small areas of Briscot, Oridia,

Mt. Vernon, and Pilchuck soils; small areas of Bellingham,

Shalcar, and Fishtrap soils in depressions; Riverwash; and

Puyallup soils that have slopes of more than 2 percent.

Included areas make up about 15 percent of the total

acreage.

Permeability is moderately rapid in the upper part of the

Puyallup soil and rapid in the lower part. Available water

capacity is moderate. The effective rooting depth is 60

inches. Runoff is very slow, and there is no hazard of

erosion. In most areas this soil is subject to occasional,

brief periods of flooding from November through April.

Downstream from Lynden, however, it is subject to

frequent, brief periods of flooding from December through

February. Channeling and deposition are common along

streambanks.

This unit is used mainly for hay and pasture or as

cropland. It also is used as woodland and as a site for

homes.

The main limitation in the areas used for hay and

pasture are the moderate available water capacity and the

hazard of flooding. Proper stocking rates, pasture rotation,

and restricted grazing during wet periods help to keep the

pasture in good condition. In summer, irrigation is required

for maximum production.

The main limitations in the areas used as cropland are

the moderate available water capacity and the hazard of

flooding. This unit is suited to all crops commonly grown in

the survey area. The principal crops are peas, sweet corn,

beans, small grain, raspberries, carrots, and corn silage. In

summer, irrigation is required for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western redcedar,

bigleaf maple, black cottonwood, and western hemlock.

The common understory plants are trailing blackberry,

salmonberry, Oregongrape, western swordfern, vine maple,

and western brackenfern.

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

index for Douglas fir is 167. On the basis of a 50-year site

curve, it is 125. The highest average growth rate in
unmanaged, even-aged stands of Douglas fir is 178

cubic feet per acre per year, occurring at age 60.

The main limitations affecting timber harvesting are the

hazard of flooding and the muddiness caused by seasonal

wetness. These limit the use of equipment to dry periods.

The use of wheeled and tracked equipment during periods

when the soil is wet causes excessive rutting. Using lowpressure ground equipment can minimize damage to the

soil. Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of soil displacement when the soil is dry.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and displacement.

Seedling establishment is the main concern affecting

timber production. The occasional flooding hinders root

respiration and thus results in a low seedling survival rate.

A low content of moisture in the surface layer during the

growing season hinders the survival of planted and

naturally established seedlings. Reforestation can be

accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily. When

openings are made in the canopy, the uncontrolled invasion

and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

The main limitation affecting homesite development is

the hazard of flooding. The main limitations on sites for

septic tank absorption fields are a poor filtering capacity in

the substratum and the hazard of flooding. Septic tankabsorption fields may not function properly during rainy:

periods because of the wetness. Installing the absorption

field in fill approved by the health district helps to overcome

these limitations.

This map unit is in capability subclass Ilw.

125-Revel loam, 5 to 30 percent slopes. This

moderately deep, well drained soil is on mountain back

slopes, ridges, and plateaus. It formed in a mixture of

volcanic ash, glacial till, colluvium, and slope alluvium

derived dominantly from sandstone and siltstone. The

native vegetation is mainly conifers and shrubs. Elevation

is 1,200 to 2,200 feet. The average annual precipitation is

about 55 inches, the average annual air temperature is

about 45 decrees F, and the average

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

leaves, and twigs 2 inches thick. When mixed to a depth of

10 inches, the surface layer is dark brown loam. The

subsoil is dark yellowish brown loam 9 inches thick. The

upper 12 inches of the substratum is light olive brown sandy

loam. The lower part is light yellowish brown sandy loam 8

inches thick. Sandstone is at a depth of about 39 inches.

The depth to sandstone or siltstone ranges from 20 to 40

inches. The content of weathered rock fragments ranges

from 35 to 60 percent throughout this profile. In some areas

the surface layer is sandy loam. In other areas the soil has

a gravelly substratum or is 40 to 60 inches deep over

bedrock.

Included in this unit are small areas of Dekapen, Oakes,

and Squalicum soils, stony areas, slump areas, poorly

drained soils in depressions, soils that are less than 20

inches deep to sandstone, and Revel soils that have slopes

of more than 30 percent or less than 5 percent. Included

areas make up about 15 percent of the total acreage.

Permeability is moderate in the Revel soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, western redcedar, and red alder. The

common understory plants are Oregongrape, red

huckleberry, western swordfern, salal, and western

brackenfern.

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

index for Douglas fir is 121. On the basis of a 50-year site

curve, it is 91. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 116 cubic

feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are

occasional snowpack and the muddiness caused by

seasonal wetness. During an average year, the snowpack

limits the use of equipment and restricts access from

January through March. The use of wheeled and tracked

equipment when the soil is wet causes excessive rutting.

Using low-pressure ground equipment can minimize

damage to the soil. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use.

Sandstone, a poor-quality rock for road construction, is

readily available. Cut and
Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Steep

skid trails and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. Carefully laying out roads and

skid trails, properly timing their use, and using low-pressure

ground equipment can reduce the degree of compaction

and puddling.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

Douglas fir or western hemlock seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Douglas fir occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass IVe.

126-Revel loam, 30 to 60 percent slopes. This

moderately deep, well drained soil is on mountain back

slopes, ridges, and plateaus. It formed in a mixture of

volcanic ash, glacial till, colluvium, and slope alluvium

derived dominantly from sandstone and siltstone. The

native vegetation is mainly conifers and shrubs. Elevation

is 1,200 to 2,200 feet. The average annual precipitation is

about 55 inches, the average annual air temperature is

about 45 degrees F, and the average frost-free period is

about 135 days.

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

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

brown loam 4 inches thick. The subsoil is dark brown

loam 12 inches thick. The substratum is dark yellowish

brown sandy loam 19 inches thick. Sandstone is at a

depth of about 35 inches. The depth to sandstone or

siltstone ranges from 20 to 40 inches. The content of

weathered rock fragments ranges from 35 to 60 percent

throughout this profile. In some areas the. surface layer is

sandy loam. In other areas the soil has a gravelly

substratum or is 40 to 60 inches deep over bedrock.

Included in this unit are small areas of Dekapen, Oakes,

and Squalicum soils, Rock outcrop, stony areas, slump

areas, poorly drained soils in depressions, soils that are

less than 20 inches deep to sandstone, and Revel soils

that have slopes of more than 60 percent or

less than 30 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the Revel soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the

hazard of water erosion is moderate.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, western redcedar, and red alder. The

common understory plants are Oregongrape, red

huckleberry, western swordfern, salal, and western

brackenfern.

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

index for Douglas fir is 121. On the basis of a 50-year site

curve, it is 91. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 116 cubic

feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are

occasional snowpack, the slope, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use. Cut

and fill slopes tend to slump when wet. Soil creep is

common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground can reduce the degree of

compaction, puddling, and erosion. Steep yarding paths,

skid trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. A moderate reduction in

productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

Douglas fir or western hemlock seedlings. If seed trees are

available, natural reforestation of cutover
areas by western hemlock and Douglas fir occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

delay the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the

bedrock, trees are occasionally subject to windthrow when

the soil is wet and winds are strong.

This map unit is in capability subclass VIle.

127-Revel-Welcome-Rock outcrop complex, 30 to 60

percent slopes. This map unit is on mountain slopes and

ridges. The native vegetation is mainly conifers and shrubs.

Elevation is 1,500 to 2,200 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 45 degrees F, and the average frostfree period is about 130 days.

This unit is 45 percent Revel loam, 30 percent

Welcome loam, and 10 percent Rock outcrop. The

components of this unit occur as areas so intricately

intermingled that mapping them separately was not

practical at the selected scale of mapping.

Included in this unit are small areas of Dekapen, Oakes,

and Squalicum soils, stony areas, slump areas, soils that

are less than 20 inches deep to sandstone, and Revel and

Welcome soils that have slopes of more than 60 percent or

less than 30 percent. Included areas make up about 15

percent of the total acreage.

The Revel soil is moderately deep and well drained. It

formed in a mixture of volcanic ash, glacial till, colluvium,

and slope alluvium derived dominantly from sandstone.

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

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

brown loam 4 inches thick. The subsoil is dark brown loam

12 inches thick. The substratum is dark yellowish brown

sandy loam 19 inches thick. It is underlain by sandstone at

a depth of about 35 inches. The depth to sandstone ranges

from 20 to 40 inches. The content of weathered rock

fragments ranges from 35 to 60 percent throughout this

profile. In some areas the surface layer is sandy loam. In

other areas the soil has a gravelly substratum or is

underlain by siltstone.

Permeability is moderate in the Revel soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the

hazard of water erosion is moderate.

The Welcome soil is deep and well drained. It formed in

a mixture of volcanic ash, glacial till, colluvium, and slope

alluvium derived dominantly from sandstone. Typically, the

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

4 inches thick. When mixed to a depth of 6 inches, the

surface layer is dark yellowish brown loam. The subsoil is

dark yellowish brown loam

17 inches thick. The upper 12 inches of the substratum is

olive brown sandy loam. The lower part is light olive brown

sandy loam. It is underlain by sandstone at a depth of 52

inches. The depth to sandstone ranges from 40 to 60

inches. The content of weathered rock fragments ranges

from 35 to 60 percent throughout this profile. In some areas

the surface layer is sandy loam or silt loam. In other areas

the soil has a gravelly substratum, is more than 60 inches

deep to sandstone, or is underlain by siltstone.

Permeability is moderate in the Welcome soil. Available

water capacity also is moderate. The effective rooting

depth is 40 to 60 inches. Runoff is medium, and the hazard

of water erosion is moderate.

Typically, the Rock outcrop is sandstone. It is hard and

generally unweathered. It occurs as steep cliffs and

irregular formations.

This unit is used as woodland. Douglas fir and western

hemlock are the main woodland species. Among the trees

of limited extent are red alder and western redcedar. The

common understory plants are red huckleberry,

Oregongrape, western swordfern, salal, and western

brackenfern.

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

index for Douglas fir on the Revel soil is 121. On the basis

of a 50-year site curve, it is 91. The highest average

growth rate in unmanaged, even-aged stands of Douglas

fir is 116 cubic feet per acre per year, occurring at age 60.

Estimates of the site index or growth rate for western

hemlock have not been made.

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

index on the Welcome soil is 129 for western hemlock and

135 for Douglas fir. On the basis of a 50-year site curve, it

is 89 for western hemlock and 106 for Douglas fir. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 198 cubic feet per acre

per year, occurring at age 50. For Douglas fir, it is 139

cubic feet per acre per year, occurring at age 70. Yields

are reduced by the extent of the Rock outcrop. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, occasional snowpack, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. The pattern of the Rock outcrop on the

landscape results in a discontinuous slope, which hinders

the use of cable yarding systems. The trees can break if

they are felled on the Rock outcrop. Because most of the

roots are
concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use.

Sandstone, a poor-quality rock for road construction, is

readily available. Cut and fill slopes tend to slump when

wet. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soils are moist and a

moderate degree of puddling when the soils are wet.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground can reduce the degree of

compaction, puddling, and erosion. Steep yarding paths,

skid trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. A moderate reduction in soil

productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

Douglas fir or western hemlock seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Douglas fir occurs periodically. The Rock

outcrop prevents the even distribution of reforestation.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the bedrock, trees are

occasionally subject to windthrow when the soils are wet

and winds are strong.

The Revel and Welcome soils are in capability

subclass VIle. The Rock outcrop is in capability

subclass Vllls.

128-Rinker very channery silt loam, 8 to 30 percent

slopes. This moderately deep, well drained soil is on

mountain back slopes and shoulder slopes. It formed in a

mixture of volcanic ash and colluvium derived from phyllite.

The native vegetation is mainly conifers and shrubs.

Elevation is 1,000 to 2,000 feet. The average annual

precipitation is about 70 inches, the average annual air

temperature is about 44 degrees F, and the average frostfree period is about 130 days.

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

leaves, and twigs 2 inches thick. When mixed to a depth of

7 inches, the surface layer is dark brown very channery silt

loam. The subsoil is dark yellowish

brown very channery silt loam 4 inches thick. The

substratum is olive brown very channery loam 19 inches

thick. Phyllite is at a depth of about 30 inches. The depth to

phyllite ranges from 20 to 40 inches. In some areas the

surface layer is channery silt loam or very channery loam.

In other areas the soil has 15 to 35 percent rock fragments

in the subsoil and substratum or is 40 to 60 inches deep

over bedrock.

Included in this unit are small areas of Montborne and

Sorensen soils, soils that are less than 20 inches deep to

phyllite or dense glacial till, stony areas, Rock outcrop, and

Rinker soils that have slopes of more than 30 percent or

less than 8 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the Rinker soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are salal,

Oregongrape, western swordfern, western brackenfern, and

vine maple.

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

index is 157 for western hemlock and is estimated to be 146

for Douglas fir. On the basis of a 50-year site curve, it is

110 for western hemlock and is estimated to be 107 ,for

Douglas fir. The highest average growth rate in unmanaged,

even-aged stands of western hemlock is 249 cubic feet per

acre per year, occurring at age 50. For Douglas fir, it is

about 153 cubic feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is

occasional snowpack. During an average year, the

snowpack limits the use of equipment and restricts access

from January through March. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and are subject to deep rutting during rainy

periods. Phyllite, a poor-quality rock for road construction, is

readily available. Extra rock is needed to maintain a stable,

uniform road surface. Cut and fill slopes tend to slump

when wet. Steep skid trails and firebreaks are subject to

rilling and gullying unless adequate water bars are provided

or a protective plant cover is established.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production.

Reforestation can be accomplished by planting western

hemlock or Douglas fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock occurs readily and reforestation by
Douglas fir occurs periodically. When openings are made in

the canopy, the uncontrolled invasion and growth of

competing plants can delay the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the bedrock, trees are occasionally subject to windthrow

when the soil is wet and winds are strong.

This map unit is in capability subclass lVe.

129-Rinker very channery silt loam, 30 to 60 percent

slopes. This moderately deep, well drained soil is on

mountain back slopes and shoulder slopes. It formed in a

mixture of volcanic ash and colluvium derived from phyllite.

The native vegetation is mainly conifers and shrubs.

Elevation is 1,000 to 2,000 feet. The average annual

precipitation is about 70 inches, the average annual air

temperature is about 44 degrees F, and the average frostfree period is about 130 days.

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

leaves, and twigs 2 inches thick. When mixed to a depth of

7 inches, the surface layer is dark brown very channery silt

loam. The subsoil is dark yellowish brown extremely

channery silt loam 4 inches thick. The substratum is olive

brown extremely channery loam 19 inches thick. Phyllite is

at a depth of about 30 inches. The depth to phyllite ranges

from 20 to 40 inches. In some areas the surface layer is

channery silt loam or very channery loam. In other areas

the soil has 15 to 35 percent rock fragments in the subsoil

and substratum or is 40 to 60 inches deep over bedrock.

Included in this unit are small areas of Montborne and

Sorensen soils, soils that are less than 20 inches deep to

phyllite or dense glacial till, stony areas, Rock outcrop, and

Rinker soils that have slopes of more than 60 percent or

less than 30 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the Rinker soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the

hazard of water erosion is moderate.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are salal,

Oregongrape, western swordfern, western brackenfern, and

vine maple.

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

index is estimated to be 157 for western hemlock and is

146 for Douglas fir. On the basis of a 50-year site curve, it

is estimated to be 110 for western hemlock and is 107 for

Douglas fir. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 249

cubic feet per acre per year, occurring at age 50.

For Douglas fir, it is about 153 cubic feet per acre per

year, occurring at age 60.

The main limitations affecting timber harvesting are

occasional snowpack, the slope, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and are subject to deep rutting during rainy

periods. Phyllite, a poor-quality rock for road construction,

is readily available. Extra rock is needed to maintain a

stable, uniform road surface. Cut and fill slopes tend to

slump when wet. Soil creep is common on this unit.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production.

Reforestation can be accomplished by planting western

hemlock or Douglas fir seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock occurs readily and reforestation by Douglas fir

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted

by the bedrock, trees are occasionally subject to windthrow

when the soil is wet and winds are strong.

This map unit is in capability subclass VIIe.

130-Riverwash. This map unit is on river bottom land

that is frequently flooded. Slopes are 0 to 2 percent. Areas

are irregular in shape and are 5 to 100 acres in size. The

native vegetation is mainly small trees, scattered shrubs,

and grass, although most areas are unvegetated. Elevation

is 40 to 900 feet. The average annual precipitation is 30 to

60 inches, the average annual air temperature is 47 to 50

degrees F, and the average frost-free period is 150 to 190

days.

No single profile is representative of this map unit.

One of the more commonly observed ones, however,

has a surface layer of very gravelly sand. The
underlying layers are stratified gravelly sand to extremely

gravelly coarse sand to a depth of 60 inches or more.

Included in this unit are small areas of Pilchuck and

Snoqualmie soils on flood plains, Xerorthents on low

terraces, and bodies of water. Included areas make up

about 15 percent of the total acreage.

Permeability is very rapid in the Riverwash. Available

water capacity is low. The effective rooting depth is limited

by a seasonal high water table, which is at or near the

surface to a depth of 2 feet throughout the year. Runoff is

very slow, and the hazard of water erosion is severe

because of the flooding and channeling. Channeling and

deposition are common along streambanks. This unit is

subject to frequent, long and very long periods of flooding

from October through July.

This unit is used for wildlife habitat or recreation. It can

be used as a source of sand and gravel; however, this use

must be weighed against the destruction of riverine habitat

that will be caused by obtaining the sand and gravel. The

main limitations in the areas used as woodland, pasture, or

cropland are the frequent flooding and the lack of soil

fertility.

This map unit is in capability subclass VIIIw.

131-Rock outcrop. This map unit is on mountainsides

and ridges. Slopes are 70 to 100 percent or more. Areas

are irregular in shape and are 5 to 400 acres in size.

Elevation is 100 to 5,500 feet.

Typically, the Rock outcrop is sandstone, phyllite,

dunite, or metasedimentary rocks. It is hard and

generally unweathered. It occurs as steep cliffs and

irregular formations.

Included in this unit are small areas of soils that were

too small to map at the selected scale and small areas of

Rubbleland.

Runoff is rapid, and the hazard of water erosion is

very severe.

This unit is used for rock quarries or wildlife habitat.

This map unit is in capability subclass Vllls.

132-Rock outcrop-Kulshan complex, 60 to 90 percent

slopes. This map unit is on mountain back slopes and

ridges. The Rock outcrop is on 60 to 90 percent slopes,

and the Kulshan soil is on 60 to 80 percent slopes. The

native vegetation is mainly conifers and shrubs. Elevation

is 3,500 to 4,500 feet. The average annual precipitation is

about 100 inches, the average annual air temperature is

about 40 degrees F, and the average frost-free period is

about 85 days.

This unit is 55 percent Rock outcrop and 25 percent

Kulshan loam. The components of this unit occur as areas

so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Shuksan and

Gallup soils, soils that are less than 20 inches deep and

that have a range in rock fragment content, organic soils in

depressions, and Kulshan soils that have slopes of less

than 60 percent. Included areas make up about 20 percent

of the total acreage.

Typically, the Rock outcrop is sandstone or

conglomerate. It is hard and generally unweathered. It

occurs as steep cliffs and irregular formations.

The Kulshan soil is moderately deep and well drained. It

formed in volcanic ash, loess, colluvium, and slope

alluvium derived dominantly from sandstone. Typically, the

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

2 inches thick. When mixed to a depth of 8 inches, the

surface layer is dark brown loam. The upper 15 inches of

the subsoil is dark brown and very dark grayish brown silt

loam. The lower 4 inches is dark brown gravelly loam.

Sandstone is at a depth of about 27 inches. The depth to

sandstone ranges from 20 to 40 inches. In some areas the

surface layer is silt loam or gravelly loam. In other areas

the soil has a very gravelly subsoil or is 40 to 60 inches

deep over bedrock.

Permeability is moderate in the Kulshan soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is rapid, and the hazard of

water erosion is severe.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent is mountain hemlock. The common

understory plants are blueleaved huckleberry, bunchberry

dogwood, and longtube twinflower.

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

index for western hemlock is estimated to be 93. On the

basis of a 50-year site curve, it is estimated to be 65. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 110 cubic feet per

acre per year, occurring at age 60. Yields are reduced by

the extent of the Rock outcrop. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are the

slope, the Rock outcrop, snowpack, and the hazard of

erosion. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. Cable yarding systems generally are used on

this unit. The pattern of the Rock outcrop on the landscape

results in a discontinuous slope, which hinders the use of

cable yarding systems. The trees can break if they are

felled on the Rock
outcrop. Because most of the roots are concentrated in the

organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Sandstone, a poor-quality

rock for road construction, is readily available. Cut and fill

slopes tend to slump when wet. Following road construction

and clearcutting, road failures and landslides are likely.

Locating roads on midslopes requires extensive cutting and

filling, which remove land from production. Soil creep is

common on this unit.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Seedling mortality is the main concern affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock and Pacific silver fir seedlings. Because

of the slope, planting seedlings is difficult. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. The

Rock outcrop prevents the even distribution of

reforestation. Because the rooting depth is restricted by the

bedrock, trees are occasionally subject to windthrow when

the Kulshan soil is wet and winds are strong.

The Rock outcrop is in capability subclass VIIIs. The

Kulshan soil is in capability subclass VIle.

133-Rubble land. This map unit is on talus slopes at

the base of rock outcrops. It consists of angular stones and

boulders. Slopes are 30 to 100 percent. The native

vegetation is mainly huckleberry, ferns, and forbs, which

are sparsely distributed over the unit. Elevation is 2,000 to

4,000 feet. The average annual precipitation is 70 to 100

inches, the average annual air temperature is 40 to 43

degrees F, and the average frost-free period is 80 to 100

days.

Typically, this unit consists of loosely piled angular

stones and boulders to a depth of 60 inches.

Included in this unit are small areas of Rock outcrop

and areas where soil is within a depth of 60 inches.

This unit is used for wildlife habitat or as a source of

aggregate.

This map unit is in capability subclass VIIIs.

134-Saar gravelly silt loam, 5 to 30 percent slopes.

This moderately deep, moderately well drained soil is on

mountain back slopes and shoulder slopes. It formed in a

mixture of volcanic ash, colluvium, and glacial till. The

native vegetation is mainly conifers and shrubs. 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 period is

about 95 days.

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

leaves, and twigs 7 inches thick. When mixed to a depth of

7 inches, the surface layer is dark brown gravelly silt loam.

The upper 15 inches of the subsoil is organic stained, dark

brown very gravelly loam and very gravelly silt loam. The

lower 7 inches is dark brown very gravelly loam. Dense

glacial till that crushes to extremely gravelly loam is at a

depth of 29 inches. The depth to dense glacial till ranges

from 20 to 40 inches. The dense glacial till is similar to a

cemented pan. In some areas the surface layer is gravelly

loam or very gravelly silt loam. In other areas the soil has

less than 35 percent rock fragments in the subsoil, is 40 to

60 inches deep to dense glacial till or bedrock, has a less

developed subsoil, has less than 6 percent organic carbon

in the upper part of the subsoil and lower part of the

surface layer, or has more than 6 percent organic carbon

throughout the profile.

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

Clendenen, and Gallup soils, Rock outcrop, poorly drained

mineral and organic soils in depressions, and Saar soils

that have slopes of more than 30 percent or less than 5

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the Saar

soil and very slow in the dense glacial till. Available water

capacity is moderate. The effective rooting depth is 20 to

40 inches. Water is perched above the dense glacial till

from November through May. Runoff is slow, and the

hazard of water erosion is slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are mountain hemlock and western

redcedar. The common understory plants are tall blue

huckleberry, deer fern, red huckleberry, longtube

twinflower, and bunchberry dogwood.

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

index for western hemlock is estimated to be 105. On the

basis of a 50-year site curve, it is estimated to be 75. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 151 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds
are less productive than the other areas of this unit.

Estimates of the site index or growth rate for Pacific

silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal wetness.

During an average year, the snowpack limits the use of

equipment and restricts access from November through

May. The use of wheeled and tracked equipment when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Rock for road construction is

not readily available. Cut and fill slopes tend to slump when

wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Steep skid trails

and firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. Because the rooting

depth is restricted by the dense glacial till, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIe.

135-Saar gravelly silt loam, 30 to 60 percent slopes.

This moderately deep, moderately well drained soil is on

mountain back slopes and shoulder slopes. It formed in a

mixture of volcanic ash, colluvium, and glacial till. The

native vegetation is mainly conifers and shrubs. Elevation

is 2,600 to 3,600 feet. The average annual precipitation is

about 90 inches, the average annual air temperature is

about 42 degrees F, and the average frost-free period is

about 95 days.

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

leaves, and twigs 7 inches thick. When mixed to a depth

of 7 inches, the surface layer is dark brown gravelly silt

loam. The upper 15 inches of the subsoil is organic

stained, dark brown very gravelly loam. The

lower 7 inches is dark brown very gravelly loam. Dense

glacial till that crushes to extremely gravelly loam is at a

depth of 29 inches. The depth to dense glacial till ranges

from 20 to 40 inches. The dense glacial till is similar to a

cemented pan. In some areas the surface layer is gravelly

loam or very gravelly silt loam. In other areas the soil has

less than 35 percent rock fragments in the subsoil, is 40 to

60 inches deep to dense glacial till or bedrock, has a less

developed subsoil, has less than 6 percent organic carbon

in the upper part of the subsoil and lower part of the

surface layer, or has more than 6 percent organic carbon

throughout the profile.

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

Clendenen, and Gallup soils, Rock outcrop, poorly drained

mineral and organic soils in depressions, and Saar soils

that have slopes of more than 60 percent or less than 30

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the

Saar soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from November through

May. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are mountain hemlock and western

redcedar. The common understory plants are tall blue

huckleberry, deer fern, red huckleberry, longtube

twinflower, and bunchberry dogwood.

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

index for western hemlock is estimated to be 105. On the

basis of a 50-year site curve, it is estimated to be 75. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 151 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces

natural fertility and the available water capacity. Unsurfaced

roads are soft and slippery when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is not readily
available. Cut and fill slopes tend to slump when wet.

Following road construction and clearcutting, road failures

and landslides are likely. Soil creep is common on this

unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and cable yarding paths, properly timing their use,

and using cable systems that lift logs entirely off the ground

can reduce the degree of compaction, puddling, and

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

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. Because the rooting

depth is restricted by the dense glacial till, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIle.

136-Saar-Hartnit complex, 5 to 40 percent slopes.

This map unit is on mountain back slopes and plateaus.

The native vegetation is mainly conifers and shrubs..

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

precipitation is about 90 inches, the average annual air

temperature is about 42 degrees F, and the average frostfree period is about 95 days.

This unit is 50 percent Saar gravelly silt loam and 35

percent Hartnit loam. The components of this unit occur as

areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Clendenen and

Gallup soils, soils that are less than 20 inches deep over

bedrock, Rock outcrop, and Saar and Hartnit soils that

have slopes of more than 40 percent or less than 5

percent. Included areas make up about 15 percent of the

total acreage.

The Saar soil is moderately deep and moderately well

drained. It formed in a mixture of volcanic ash,

colluvium, and glacial till. Typically, the surface is

covered with a mat of needles, leaves, and twigs 5

inches thick. When mixed to a depth of 7 inches, the

surface layer is dark brown gravelly silt loam. The upper 9

inches of the subsoil is yellowish red very gravelly loam.

The lower 10 inches is olive brown very gravelly loam.

Dense glacial till that crushes to extremely gravelly sandy

loam is at a depth of 26 inches. The depth to dense glacial

till ranges from 20 to 40 inches. The dense glacial till is

similar to a cemented pan. In some areas the surface layer

is gravelly silt loam or very gravelly loam. In other areas

the soil has less than 35 percent rock fragments in the

subsoil, is 40 to 60 inches deep to dense glacial till or

bedrock, has a less developed subsoil, has less than 6

percent organic carbon in the upper part of the subsoil or

lower part of the surface layer, or has more than 6 percent

organic carbon throughout the profile.

Permeability is moderate in the upper part of the Saar

soil and very slow in the dense glacial till. Available water

capacity is moderate. The effective rooting depth is 20 to

40 inches. Water is perched above the dense glacial till

from November through May. Runoff is slow, and the

hazard of water erosion is slight.

The Hartnit soil is moderately deep and well drained. It

formed in a mixture of volcanic ash and colluvium over

glacial till. Typically, the surface is covered with a mat of

needles, leaves, and twigs 3 inches thick. The surface layer

is dark brown loam 4 inches thick. The upper 6 inches of

the subsoil is organic stained, dark brown loam. The lower

7 inches is dark yellowish brown loam. The upper 10

inches of the substratum is olive brown gravelly loam. The

lower 12 inches is dark yellowish brown and olive brown

very gravelly loam. Sandstone is at a depth of about 39

inches. The depth to bedrock ranges from 20 to 40 inches.

In some areas the surface layer is loam or gravelly silt

loam. In other areas the soil has less than 6 percent

organic carbon in the upper part of the subsoil, has a less

developed subsoil, or is 40 to 60 inches deep over

bedrock.

Permeability is moderate in the Hartnit soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are mountain hemlock, Douglas fir,

and western redcedar. The common understory plants are

tall blue huckleberry, deer fern, red huckleberry, longtube

twinflower, and bunchberry dogwood.

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

index for western hemlock on both soils is estimated to be

105. On the basis of a 50-year site curve, it is estimated to

be 75. The highest average growth rate in
unmanaged, even-aged stands of western hemlock is about

151 cubic feet per acre per year, occurring at age 60.

Areas on ridgetops that are subject to strong, persistent

winds are less productive than the other areas of this unit.

Estimates of the site index or growth rate for Pacific silver

fir have not been made.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal wetness.

During an average year, the snowpack limits the use of

equipment and restricts access from November through

May. The use of wheeled and tracked equipment when the

soils are wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soils.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Rock for road construction is

readily available. Cut and fill slopes tend to slump when

wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling. Steep skid trails and firebreaks

are subject to rilling and gullying unless adequate water

bars are provided or a protective plant cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. Because the rooting

depth is restricted by the dense glacial till or bedrock, trees

are occasionally subject to windthrow when the soils are

wet and winds are strong.

The Saar and Hartnit soils are in capability subclass

VIe.

137-Sandun very gravelly sandy loam, 5 to 30

percent slopes. This very deep, well drained soil is on

outwash terraces, terrace escarpments, and mountain foot

slopes. It formed in a mixture of volcanic ash and loess

over glacial outwash derived dominantly from dunite. The

native vegetation is mainly conifers and

shrubs. Elevation is 1,200 to 2,500 feet. The average

annual precipitation is about 80 inches, the average

annual air temperature is about 43 degrees F, and the

average frost-free period is about 110 days.

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

leaves, and twigs 3 inches thick. The surface layer when

mixed to a depth of 7 inches is dark reddish brown very

gravelly sandy loam. The subsoil is dark brown very

gravelly sandy loam 17 inches thick. The upper 12 inches

of the substratum is dark yellowish brown very gravelly

loamy sand. The lower part to a depth of 60 inches is olive

brown very gravelly loamy sand. The depth to very gravelly

sand or loamy sand ranges from 20 to 36 inches. In some

areas the surface layer is gravelly sandy loam or very

gravelly loam. In other areas the soil has more than 6

percent organic carbon in the upper part of the subsoil, is

dominated by rock fragments other than dunite, or has a

substratum of very gravelly sandy loam.

Included in this unit are small areas of Jackman soils,

soils that are moderately deep over bedrock or dense

glacial till and are derived dominantly from dunite, and

Sandun soils that have slopes of more than 30 percent or

less than 5 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderately rapid in the upper part of

the Sandun soil and very rapid in the substratum.

Available water capacity is low. The effective rooting depth

is 60 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent is red alder. The common understory

plants are salal, red huckleberry, and western swordfern.

Vegetation is somewhat stunted and sparse because of the

toxicity of the dunite-derived soil.

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

for western hemlock is estimated to be 135. On the basis

of a 50-year site curve, it is estimated to be 95. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 209 cubic feet per acre

per year, occurring at age 50. Estimates of the site index

or growth rate for Douglas fir have not been made.

The main limitation affecting timber harvesting is

occasional snowpack. During an average year, the

snowpack limits the use of equipment and restricts access

from January through March. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to rutting during rainy periods. Logging roads

require suitable surfacing for year-round use. Rounded

pebbles and cobbles for road
construction are readily available. Cut and fill slopes

tend to ravel when dry.

Equipment and logs on the surface result in a moderate

degree of soil displacement when the soil is dry. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of displacement. Steep skid trails and firebreaks

are subject to rilling and gullying unless adequate water

bars are provided or a protective plant cover is

established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of

other important minerals, and a low content of moisture in

the surface layer during the growing season hinder the

survival of planted and naturally established seedlings.

Reforestation can be accomplished by planting western

hemlock or Douglas fir seedlings, which are adapted to the

toxicity of dunite soils. If seed trees are available, natural

reforestation of cutover areas by western hemlock occurs

readily. Trees grow poorly and lack vigor on soils that are

derived from dunite.

This map unit is in capability subclass lVe.

138-Sandun very gravelly sandy loam, 30 to 60

percent slopes. This very deep, well drained soil is on

terrace escarpments and mountain foot slopes. It formed in

a mixture of volcanic ash and loess over glacial outwash

derived dominantly from dunite. The native vegetation is

mainly conifers and shrubs. Elevation is 1,200 to 2,500

feet. The average annual precipitation is about 80 inches,

the average annual air temperature is about 43 degrees F,

and the average frost-free period is about 110 days.

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

leaves, and twigs 3 inches thick. When mixed to a depth of

7 inches, the surface layer is dark reddish brown very

gravelly sandy loam. The subsoil is dark brown very

gravelly sandy loam 17 inches thick. The upper 12 inches

of the substratum is dark yellowish brown very gravelly

loamy sand. The lower part to a depth of 607 inches is

olive brown very gravelly loamy sand. The depth to very

gravelly sand or loamy sand ranges from 20 to 36 inches.

In some areas the surface layer is gravelly sandy loam or

very gravelly loam. In other areas the soil has more than 6

percent organic carbon in the upper part of the subsoil, is

dominated by rock fragments other than dunite, or has a

substratum of very gravelly sandy loam.

Included in this unit are small areas of Jackman soils,

soils that are moderately deep over bedrock or dense

glacial till and are derived dominantly from dunite, and

Sandun soils that have slopes of more than

60 percent or less than 30 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderately rapid in the upper part of the

Sandun soil and very rapid in the substratum. Available

water capacity is low. Runoff is medium, and the hazard of

water erosion is moderate.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent is red alder. The common understory

plants are salal, red huckleberry, and western swordfern.

Vegetation is somewhat stunted and sparse because of the

toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 135. On the

basis of a 50-year site curve, it is estimated to be 95. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 209 cubic feet per acre

per year, occurring at age 50. Estimates of the site index

or growth rate for Douglas fir have not been made.

The main limitations affecting timber harvesting are the

slope, occasional snowpack, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to rutting during rainy periods. Logging roads

require suitable surfacing for year-round use. Rounded

pebbles and cobbles for road construction are readily

available. Cut and fill slopes tend to ravel when dry. Soil

creep is common on this unit.

Equipment and logs on the surface result in a moderate

degree of soil displacement when the soil is dry. Carefully

laying out roads and cable yarding paths, properly timing

their use, and using cable systems that lift logs entirely off

the ground can reduce the hazards of displacement and

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

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of

other important minerals, and a low content of moisture in

the surface layer during the growing season hinder the

survival of planted and naturally established seedlings.

Reforestation can be accomplished by planting western

hemlock or Douglas
fir seedlings, which are adapted to the toxicity of dunite

soils. If seed trees are available, natural reforestation of

cutover areas by western hemlock occurs readily. Trees

grow poorly and lack vigor on soils that are derived from

dunite.

This map unit is in capability subclass VIle.

139-Sehome loam, 2 to 8 percent slopes. This

moderately deep, moderately well drained soil is on

glacially modified mountain foot slopes and in valleys. It

formed in a mixture of volcanic ash and loess over glacial

till. The native vegetation is mainly conifers and shrubs.

Elevation is 200 to 1,100 feet. The average annual

precipitation is about 50 inches, the average annual air

temperature is about 49 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 0.5 inch thick. The surface layer is dark

brown loam 11 inches thick. The subsoil is dark yellowish

brown gravelly loam 15 inches thick. Dense glacial till that

crushes to very gravelly loam is at a depth of 26 inches.

The depth to dense glacial till ranges from 24 to 40 inches.

The dense glacial till is similar to a cemented pan. In some

areas the surface layer is silt loam, gravelly silt loam, or

gravelly loam. In other areas the soil has 35 to 45 percent

rock fragments in the subsoil, is 40 to 60 inches deep to

dense glacial till, or has dominantly phyllitic rock fragments.

Included in this unit are small areas of Nati, Squires,

Barneston, Winston, and Blethen soils, small areas of

Bellingham soils in depressions, soils that are similar to the

Sehome soil but have a clayey or very gravelly sand

substratum, and Sehome soils that have slopes of more

than 8 percent or less than 2 percent. Included areas make

up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Sehome soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 24 to 40 inches. Water is perched above the

dense glacial till from December through April. Runoff is

slow, and the hazard of water erosion is slight.

This unit is used mainly as woodland. Some areas are

used for hay and pasture or as a site for homes.

The main limitations in the areas used for hay and

pasture are the seasonal high water table and the hazard

of erosion during periods of reestablishment. Proper

stocking rates, pasture rotation, and restricted grazing

during short wet periods help to keep the pasture in good

condition and help to control runoff and water erosion.

Some areas have been partially drained, but adequate

drainage systems have not been maintained. The wetness

can be reduced in some areas

by diversions, which intercept water, and by open

ditches, which remove excess water.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, and bigleaf maple. The common

understory plants are salal, Oregongrape, western

swordfern, red huckleberry, vine maple, western

brackenfern, and salmonberry.

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

index for Douglas fir is 180. On the basis of a 50-year site

curve, it is 135. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 191 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

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

not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the dense glacial till, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

The main limitation for homesite development is the

seasonal high water table. The wetness can be reduced by

building the house on a pad and by installing drainage tile

around footings if a suitable outlet is available. The dense

glacial till is rippable and, therefore, is not a serious

limitation for most engineering uses. The main limitations

on sites for septic tank absorption fields are the very slow

permeability in the dense glacial till and the seasonal high

water table. These limitations can be overcome by using

interceptor drains, by installing the absorption field at a

shallow depth, and by installing absorption lines that are

longer than normal and that are on the contour. Installing

the absorption field in the loamy
subsoil or in fill approved by the health district also

helps to overcome these limitations. This map unit is

in capability subclass IIe.

140-Sehome loam, 8 to 15 percent slopes. This

moderately deep, moderately well drained soil is on

mountain foot slopes. It formed in a mixture of volcanic ash

and loess over glacial till. The native vegetation is mainly

conifers and shrubs. Elevation is 300 to 900 feet. The

average annual precipitation is about 50 inches, the

average annual air temperature is about 49 degrees F, and

the average frost-free period is about 160 days.

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

leaves, and twigs 3 inches thick. The surface layer is dark

brown loam 4 inches thick. The upper 9 inches of the

subsoil is strong brown gravelly loam. The lower 26 inches

is yellowish brown gravelly loam. Dense glacial till that

crushes to very gravelly loam is at a depth of 39 inches.

The depth to dense glacial till ranges from 24 to 40 inches.

The dense glacial till is similar to a cemented pan. In some

areas the surface layer is silt loam, gravelly silt loam, or

gravelly loam. In other areas the soil has 35 to 45 percent

rock fragments in the subsoil, is 40 to 60 inches deep to

dense glacial till, or has dominantly phyllitic rock fragments.

Included in this unit are small areas of Nati, Squires,

Barneston, Winston, and Blethen soils, small areas of

Bellingham soils in depressions, soils that are similar to the

Sehome soil but have a clayey or gravelly sand

substratum, and Sehome soils that have slopes of more

than 15 percent or less than 8 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Sehome soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 24 to 40 inches. Water is perched

above the dense glacial till from December through

April. Runoff is medium, and the hazard of water

erosion is moderate.

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

hay and pasture and as cropland.

The main limitations in the areas used for hay and

pasture are the seasonal high water table and the hazard

of water erosion. Proper stocking rates, pasture rotation,

and restricted grazing during short wet periods help to keep

the pasture in good condition and help to control runoff and

water erosion. Some areas have been partially drained, but

adequate drainage systems have not been maintained. The

wetness can be reduced in some areas by diversions,

which intercept water, and by open ditches, which remove

excess water.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, and bigleaf maple. The common

understory plants are salal, Oregongrape, western

swordfern, red huckleberry, vine maple, western

brackenfern, and salmonberry.

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

index for Douglas fir is 180. On the basis of a 50-year site

curve, it is 135. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 191 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet causes

excessive rutting. Using low-pressure ground equipment

can minimize damage to the soil. Unsurfaced roads are soft

when wet and are subject to deep rutting during rainy

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

available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily. When openings are made in the canopy,

the uncontrolled invasion and growth of competing plants

can prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the

dense glacial till, trees are occasionally subject to

windthrow when the soil is wet and winds are strong.

The main limitations for homesite development are the

slope and the seasonal wetness. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is

available. Excavation for building sites is limited by the

hardpan. The hardpan is rippable and, therefore, is not a

serious limitation for most engineering uses.

The main limitations on sites for septic tank absorption

fields are the very slow permeability in the cemented pan,

the slope, and the seasonal wetness. These limitations can

be overcome by using interceptor drains, by installing the

absorption field at a shallow depth, and by installing

absorption lines that are longer than normal and that are

on the contour. Installing the absorption field in the loamy

subsoil or in fill approved
by the health district also helps to overcome these

limitations. During the rainy season, the effluent from

onsite sewage disposal systems can seep at points

downslope.

This map unit is in capability subclass Ille.

141-Sehome gravelly loam, 15 to 30 percent slopes.

This moderately deep, moderately well drained soil is on

glacially modified mountain foot slopes. It formed in a

mixture of volcanic ash and loess over glacial till. The

native vegetation is mainly conifers and shrubs. Elevation

is 300 to 900 feet. The average annual precipitation is

about 50 inches, the average annual air temperature is

about 49 degrees F, and the average frost-free period is

about 160 days.

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

leaves, and twigs 3 inches thick. The surface layer is dark

yellowish brown gravelly loam 12 inches thick. The upper

13 inches of the subsoil is light olive brown gravelly loam.

The lower 13 inches is light brownish gray and yellowish

brown, mottled gravelly loam. Dense glacial till that crushes

to very gravelly loam is at a depth of 38 inches. The depth

to dense glacial till ranges from 24 to 40 inches. The

dense glacial till is similar to a cemented pan. In some

areas the surface layer is loam, silt loam, or gravelly silt

loam. In other areas the soil has 35 to 45 percent rock

fragments in the subsoil, is 40 to 60 inches deep to glacial

till, or has dominantly phyllitic rock fragments.

Included in this unit are small areas of Squires,

Barneston, Winston, and Blethen soils, soils that are similar

to the Sehome soil but have a clayey or gravelly sand

substratum, and Sehome soils that have slopes of more

than 30 percent or less than 15 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Sehome soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 24 to 40 inches. Water is perched above the

dense glacial till from December through April. Runoff is

slow, and the hazard of water erosion is slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are salal,

Oregongrape, western swordfern, red huckleberry, vine

maple, western brackenfern, and salmonberry.

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

index for Douglas fir is 180. On the basis of a 50-year site

curve, it is 135. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 191 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

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

not readily available. Cut and fill slopes tend to slump

when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling. Steep skid

trails and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted

by the dense glacial till, trees are occasionally subject to

windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass IVe.

142-Sehome gravelly loam, 30 to 60 percent slopes.

This moderately deep, moderately well drained soil is on

glacially modified mountain foot slopes. It formed in a

mixture of volcanic ash and loess over glacial till. The

native vegetation is mainly conifers and shrubs. Elevation

is 300 to 900 feet. The average annual precipitation is

about 50 inches, the average annual air temperature is

about 49 degrees F, and the average frost-free period is

about 160 days.

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

leaves, and twigs 3 inches thick. The surface layer is dark

yellowish brown gravelly loam 12 inches thick. The upper

13 inches of the subsoil is light olive brown gravelly loam.

The lower 13 inches is light brownish gray and yellowish

brown, mottled gravelly loam. Dense glacial till that crushes

to very gravelly loam is at a depth of 38 inches. The depth

to dense glacial till ranges from 24 to 40 inches. The

dense glacial till is similar to a cemented pan. In some

areas the surface layer is loam, silt loam, or gravelly silt

loam. In other areas the soil has 35 to 45 percent rock

fragments in the subsoil, is 40 to 60 inches deep to
dense glacial till, or has dominantly phyllitic rock

fragments.

Included in this unit are small areas of Squires,

Barneston, Winston, and Blethen soils, soils that are

similar to the Sehome soil but have a clayey or gravelly

sand substratum, and Sehome soils that have slopes of

more than 60 percent or less than 30 percent. Included

areas make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Sehome soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 24 to 40 inches. Water is perched

above the dense glacial till from December through

April. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are salal,

Oregongrape, western swordfern, red huckleberry, vine

maple, western brackenfern, and salmonberry.

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

index for Douglas fir is 180. On the basis of a 50-year site

curve, it is 135. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 191 cubic

feet per acre per year, occurring at age 60.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is harvested,

the slope restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Unsurfaced roads are

soft when wet and are subject to deep rutting during rainy

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

available. Cut and fill slopes tend to slump when wet.

Following road construction and clearcutting, road failures

and landslides are likely. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground can reduce the degree of

compaction, puddling, and erosion.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover

areas by red alder occurs readily. When openings are

made in the canopy, the uncontrolled invasion and

growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

Because the rooting depth is restricted by the dense

glacial till, trees are occasionally subject to windthrow

when the soil is wet and winds are strong.

This map unit is in capability subclass VIle.

143-Shalcar muck, drained, 0 to 2 percent slopes.

This very deep, very poorly drained soil is in depressions on

outwash terraces, till plains, and stream terraces. It has

been artificially drained. It formed in herbaceous and woody

organic deposits, overlying alluvium and glaciofluvial

deposits. The native vegetation is mainly shrubs, forbs, and

trees. Elevation is near sea level to 600 feet above sea

level. The average annual precipitation is about 45 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free period is about 170 days.

Typically, the surface layer is black muck 37 inches thick.

The upper 15 inches of the underlying material is very dark

grayish brown loam. The lower part to a depth of 60 inches

is gravelly sand. It is variegated but is dominantly dark

gray. In some areas the soil has hemic material in the

surface layer or is not underlain by gravelly sand. In other

areas the underlying material is below a depth of 51 inches.

Included in this unit are small areas of Bellingham,

Snohomish, Puget, Sumas, Fishtrap, and Hale soils,

ponded areas, and Shalcar soils that have not been

drained or have slopes of more than 2 percent. Included

areas make up about 10 percent of the total acreage.

Permeability is moderate in the upper part of the

Shalcar soil and very rapid in the lower part. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a depth

of 0.5 foot to 1.5 feet from October through May. Runoff

usually is very slow, but the soil may be ponded during the

winter. There is no hazard of erosion.

This unit is used mainly for hay and pasture or as

cropland. The included undrained Shalcar soils are

used as woodland.

The main limitation in the areas used for hay and

pasture are the high water table. Proper stocking rates,

pasture rotation, and restricted grazing during wet periods

help to keep the pasture in good condition. The wetness

limits the choice of plants and the period of cutting or

grazing and increases the risk of winterkill. Grazing when

the soil is wet results in compaction of the surface layer

and poor tilth.

The main limitations in the areas used as cropland are

the high water table and the soil acidity. This soil is well

suited to most crops commonly grown in the survey area if

adequate drainage systems are maintained. The principal

crops are potatoes, blueberries, and corn silage. Tile drains

and field ditches should be maintained. They permit

fieldwork to be conducted
earlier in the spring and increase the yields. During the

growing season, the water table is artificially lowered to a

depth of about 3 to 5 feet. Subsidence is minimized if the

water table is maintained directly below the root zone during

the growing season and then allowed to return to the

surface during the winter. Using regulating structures in

open ditches as a means of subirrigation reduces the extent

of subsidence. In summer, irrigation is required for

maximum production. Soil acidity can be reduced by adding

lime.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, lodgepole pine, and Sitka spruce. The common

understory plants are willow, Douglas spirea, salmonberry,

stinging nettle, and sedges.

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

index for red alder is estimated to be 85. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 92 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The high water

table limits the use of equipment to dry periods.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is needed

to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The seasonal high water table hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If the unit is used for homesite development, the main

limitations are the high water table and the low strength.

The wetness can be reduced by building the house on a

pad and by installing drainage tile around footings if a

suitable outlet is available. If buildings are constructed on

this soil, the muck should be excavated

or the buildings should be constructed on piles anchored

in the mineral soil. The design of buildings and roads

can offset the limited ability of the soil to support a load.

The main limitation on sites for septic tank absorption

fields is the wetness. Installing the absorption field in fill

approved by the health district helps to compensate for

this limitation.

This map unit is in capability subclass Ilw.

144-Shalcar and Fishtrap soils, 0 to 2 percent

slopes. This map unit is in backswamps on flood plains

and in depressional areas on till plains, outwash terraces,

and stream terraces. The soils in this unit formed in

herbaceous and woody organic deposits overlying glacial

fluvial deposits. The native vegetation is mainly shrubs and

forbs. Elevation is 300 to 1,000 feet. The average annual

precipitation is about 50 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

This unit is 60 percent Shalcar muck and 30 percent

Fishtrap muck. The components of this unit occur as

areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of mineral soils

that are ponded, Pangborn soils, and areas where the

soils have been partially drained. Included areas make up

about 10 percent of the total acreage.

The Shalcar soil is very deep and very poorly drained.

Typically, the surface layer is very dark brown muck 25

inches thick. The underlying material to a depth of 60

inches is gray and greenish gray silty clay loam. The depth

to mineral material ranges from 16 to 51 inches. In some

areas the surface layer is mucky silt loam or hemic

material.

Permeability is moderate in the Shalcar soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at or above the

surface from October through May. Runoff is very slow or

ponded, and there is no hazard of erosion.

The Fishtrap soil is very deep and very poorly drained.

Typically, the surface layer is black muck 16 inches thick.

The upper 22 inches of the underlying material is black

muck. The next 5 inches is dark gray silt loam. The

lower part to a depth of 60 inches is sand. It is

variegated but is dominantly dark gray. In some areas

the surface layer is mucky silt loam or hemic material.

Permeability is moderate in the upper part of the

Fishtrap soil and very rapid in the lower part of the

underlying material. Available water capacity is high. The

effective rooting depth is limited by a seasonal high
water table, which is at or above the surface from

October through May. Runoff is very slow or ponded,

and there is no hazard of erosion.

This unit is used for wildlife habitat.

The Shalcar and Fishtrap soils are in capability

subclass VIw.

145-Shuksan gravelly silt loam, 5 to 30 percent

slopes. This moderately deep, moderately well drained soil

is on mountain slopes and plateaus. It formed in a mixture

of volcanic ash, loess, and colluvium over glacial till. The

native vegetation is mainly conifers and shrubs. Elevation

is 3,000 to 4,500 feet. The average annual precipitation is

about 95 inches, the average annual air temperature is

about 41 degrees F, and the average frost-free period is

about 95 days.

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

leaves, twigs, and wood fragments 9 inches thick. When

mixed to a depth of 7 inches, the surface layer is dark

reddish brown gravelly silt loam. The upper 8 inches of the

subsoil is organic stained, strong brown gravelly silt loam.

The lower 20 inches is organic stained, dark brown and

dark yellowish brown very gravelly loam. Dense glacial till

that crushes to very gravelly sandy loam is at a depth of 35

inches. The depth to dense glacial till ranges from 20 to 40

inches. The dense glacial till is similar to a cemented pan.

In some areas the surface layer is silt loam or gravelly

loam. In other areas the soil has 15 to 35 percent rock

fragments in the subsoil, is 40 to, 60 inches deep to dense

glacial till or bedrock, has a less developed subsoil, or has

less than 6 percent organic carbon in the upper part of the

subsoil and lower part of the surface layer.

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

Clendenen, and Gallup soils, Rock outcrop, poorly drained

mineral and organic soils in depressions, and Shuksan soils

that have slopes of more than 30 percent or less than 5

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the

Shuksan soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from November through

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

slight.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are mountain hemlock and western

redcedar. The common understory plants are tall blue

huckleberry, red huckleberry, bunchberry dogwood,

longtube twinflower, and deer fern.

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

index for western hemlock is estimated to be 98. On the

basis of a 50-year site curve, it is estimated to be 70. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 118 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack and the muddiness caused by seasonal wetness.

During an average year, the snowpack limits the use of

equipment and restricts access from November through

May. The use of wheeled and tracked equipment when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Logging roads require suitable

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

not readily available. Cut and fill slopes tend to slump

when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep skid trails and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling mortality is the main concern affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. If seed trees

are available, natural reforestation of cutover areas by

western hemlock and Pacific silver fir occurs periodically.

Because the rooting depth is restricted by the dense glacial

till, trees are occasionally subject to windthrow when the

soil is wet and winds are strong.

This map unit is in capability subclass Vle.

146-Shuksan gravelly silt loam, 30 to 60 percent

slopes. This moderately deep, moderately well drained

soil is on mountain slopes and plateaus. It formed in a

mixture of volcanic ash, loess, and colluvium over
glacial till. The native vegetation is mainly conifers and

shrubs. Elevation is 3,000 to 4,500 feet. The average

annual precipitation is about 95 inches, the average annual

air temperature is about 41 degrees F, and the average

frost-free period is about 95 days.

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

leaves, twigs, and wood fragments 9 inches thick. When

mixed to a depth of 7 inches, the surface layer is dark

reddish brown gravelly silt loam. The upper 8 inches of the

subsoil is organic stained, strong brown gravelly silt loam.

The lower 20 inches is organic stained, dark brown and

dark yellowish brown very gravelly loam. Dense glacial till

that crushes to very gravelly sandy loam is at a depth of

35 inches. The depth to dense glacial till ranges from 20 to

40 inches. The dense glacial till is similar to a cemented

pan. In some areas the surface layer is silt loam or gravelly

loam. In other areas the soil has 15 to 35 percent rock

fragments in the subsoil, is 40 to 60 inches deep to dense

glacial till or bedrock, has a less developed subsoil, or has

less than 6 percent organic carbon in the upper part of the

subsoil and lower part of the surface layer.

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

Clendenen, and Gallup soils, Rock outcrop, poorly drained

mineral and organic soils in depressions, and Shuksan

soils that have slopes of more than 60 percent or less than

30 percent. Included areas make up about 15 percent of

the total acreage.

Permeability is moderate in the upper part of the

Shuksan soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from November through

May. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are mountain hemlock and western

redcedar. The 'common understory plants are tall blue

huckleberry, red huckleberry, bunchberry dogwood,

longtube twinflower, and deer fern.

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

index for western hemlock is estimated to be 98. On the

basis of a 50-year site curve, it is estimated to be 70. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 118 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit. Estimates of the site index or

growth rate for Pacific silver fir have not been made.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During

an average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces

natural fertility and the available water capacity. Unsurfaced

roads are soft and slippery when wet and are subject to

deep rutting during rainy periods. Logging roads require

suitable surfacing for year-round use. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and cable yarding paths, properly timing their

use, and using cable systems that lift logs entirely off the

ground can reduce the degree of compaction, puddling,

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

are subject to rilling and gullying unless adequate water

bars are provided or a protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of the seedlings

and delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. Because the rooting

depth is restricted by the dense glacial till, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIle.

147-Shuksan-Kulshan-Rock outcrop complex, 50 to

80 percent slopes. This map unit is on mountain slopes,

plateaus, and ridges. The native vegetation is mainly

conifers and shrubs. Elevation is 3,000 to 4,500 feet. The

average annual precipitation is about 95 inches, the

average annual air temperature is about 41 degrees F, and

the average frost-free period is about 90 days.

This unit is 35 percent Shuksan gravelly silt loam, 25

percent Kulshan loam, and 20 percent Rock outcrop. The

components of this unit occur as areas so intricately

intermingled that mapping them separately
was not practical at the selected scale of mapping.

Included in this unit are small areas of Clendenen and

Gallup soils, poorly drained mineral soils in swales, soils

that are less than 20 inches deep to dense glacial till or

bedrock, stony areas, slump areas, and Shuksan and

Kulshan soils that have slopes of more than 80 percent or

less than 50 percent. Included areas make up about 20

percent of the total acreage.

The Shuksan soil is moderately deep and moderately

well drained. It formed in a mixture of volcanic ash, loess,

and colluvium over glacial till. Typically, the surface is

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

fragments 9 inches thick. When mixed to a depth of 7

inches, the surface layer is dark reddish brown gravelly silt

loam. The upper 8 inches of the subsoil is organic stained,

strong brown gravelly silt loam. The lower 20 inches is

organic stained, dark brown and dark yellowish brown very

gravelly loam. Dense glacial till that crushes to very

gravelly sandy loam is at a depth of 35 inches. The depth

to dense glacial till ranges from 20 to 40 inches. The dense

glacial till is similar to a cemented pan. In some areas the

surface layer is silt loam or gravelly loam. In other areas

the soil has 15 to 35 percent rock fragments in the subsoil,

is 40 to 60 inches deep to dense glacial till or bedrock, has

a less developed subsoil, or has less than 6 percent

organic carbon in the upper part of the subsoil and lower

part of the surface layer.

Permeability is moderate in the upper part of the

Shuksan soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 20 to 40 inches. Water is perched above the dense

glacial till from November through May. Runoff is rapid, and

the hazard of water erosion is severe.

The Kulshan soil is moderately deep and well drained. It

formed in volcanic ash, loess, colluvium, and slope

alluvium derived dominantly from sandstone. Typically, the

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

and bark 7 inches thick. When mixed to a depth of 8

inches, the surface layer is dark red loam. The upper 6

inches of the subsoil is organic stained, yellowish red

gravelly loam. The lower 16 inches is yellowish red and

dark reddish brown gravelly loam and cobbly loam.

Sandstone is at a depth of about 30 inches. The depth to

sandstone ranges from 20 to 40 inches. In some areas the

surface layer is silt loam or gravelly loam. In other areas

the soil has a very gravelly subsoil or is 40 to 60 inches

deep over bedrock.

Permeability is moderate in the Kulshan soil. Available

water capacity also is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is rapid, and the hazard of

water erosion is severe.

Typically, the Rock outcrop is sandstone or

metasedimentary rock. It is hard and generally

unweathered. It occurs as steep cliffs and irregular

formations.

This unit is used as woodland. Western hemlock and

Pacific silver fir are the main woodland species. Among the

trees of limited extent are mountain hemlock and western

redcedar. The common understory plants are tall blue

huckleberry, red huckleberry, bunchberry dogwood,

Iongtube twinflower, and deer fern.

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

index for western hemlock on the Shuksan soil is

estimated to be 98. On the basis of a 50-year site curve,

it is estimated to be 70. The highest average growth rate

in unmanaged, even-aged stands of western hemlock is

about 118 cubic feet per acre per year, occurring at age

60.

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

index for western hemlock on the Kulshan soil is estimated

to be 93. On the basis of a 50-year site curve, it is

estimated to be 65. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is about

110 cubic feet per acre per year, occurring at age 60.

Yields are reduced by the extent of the Rock outcrop.

Areas on ridgetops that are subject to strong, persistent

winds are less productive than the other areas of this unit.

Estimates of the site index or growth rate for Pacific silver

fir have not been made.

The main limitations affecting timber harvesting are the

slope, the Rock outcrop, snowpack, and the hazard of

erosion. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. The pattern of the Rock outcrop on the

landscape results in a discontinuous slope, which hinders

the use of cable yarding systems. These systems generally

are used on this unit. The trees can break if they are felled

on the Rock outcrop. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Logging roads require

suitable surfacing for year-round use. Sandstone, a poorquality rock for road construction, is readily available. Cut

and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. Locating roads on midslopes requires extensive

cutting and filling, which remove land from production. Soil

creep is common on this unit. Steep yarding paths, skid

trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established.

Seedling mortality is the main concern affecting
timber production. A low soil temperature, deep snowpack,

and a short growing season hinder the survival of planted

and natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. Because of

the slope, planting seedlings is difficult. If seed trees are

available, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. The Rock

outcrop prevents the even distribution of reforestation.

Because the rooting depth is restricted by the bedrock or

dense glacial till, trees are occasionally subject to windthrow

when the soils are wet and winds are strong.

The Shuksan and Kulshan soils are in capability

subclass VIle. The Rock outcrop is in capability

subclass Vllls.

148-Skipopa silt loam, 0 to 8 percent slopes. This

very deep, somewhat poorly drained soil is on terraces. It

formed in loess and volcanic ash over glaciolacustrine

sediments. It is in convex areas and frequently on

elongated ridges. The native vegetation is mainly conifers

and shrubs. Elevation is 50 to 300 feet. The average

annual precipitation is about 45 inches, the average annual

air temperature is about 50 degrees F, and the average

frost-free period is about 170 days.

Typically, the surface layer is dark brown silt loam 8

inches thick. The upper 4 inches of the subsoil is dark

brown silt loam. The next 4 inches is dark yellowish

brown, mottled silt loam. The lower 4 inches is brown and

grayish brown, mottled silty clay loam. The upper 24

inches of the substratum is brown and dark brown, mottled

silty clay loam. The lower part to a depth of 60 inches is

light brownish gray and light yellowish brown, mottled silty

clay loam. The depth to silty clay or silty clay loam ranges

from 14 to 24 inches. In some areas the surface layer is

loam. In other areas the substratum contains lenses of

sand or is 18 to 35 percent clay.

Included in this unit are small areas of Bellingham,

Labounty, and Shalcar soils in depressions and small

areas of Skipopa soils that have slopes of more than 8

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is very slow in the Skipopa soil. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a depth

of 1 to 2 feet from October through June. Runoff is slow,

and the hazard of water erosion is slight.

This unit is used mainly for hay and pasture. It also is

used as woodland and as a site for homes. The main

limitations in the areas used for hay and

pasture are the high water table and the very slow

permeability. Proper stocking rates, pasture rotation, and

restricted grazing during wet periods help to keep the

pasture in good condition. Grazing when the soil is wet

results in compaction of the surface layer and poor tilth.

The water table limits the use of this unit to grasses unless

a drainage system is installed. The wetness limits the

choice of plants and the period of cutting or grazing and

increases the risk of winterkill. Tile drains and field ditches

are needed to lower the high water table if deep-rooted

plants are to be grown. Some areas have been partially

drained, mainly by open ditches, but adequate drainage

systems have not been maintained. Installing a drainage

system permits fieldwork to be conducted earlier in the

spring and increases yields. The wetness can be reduced

in some areas by diversions, which intercept water, and by

open ditches, which remove excess water.

Douglas fir and red alder are the main woodland

species. Among the trees of limited extent are western

redcedar, western hemlock, and bigleaf maple. The

common understory plants are western swordfern,

salmonberry, red huckleberry, western brackenfern, and

trailing blackberry.

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

index for Douglas fir is 151. On the basis of a 50-year site

curve, it is 116 for Douglas fir and 97 for red alder. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is 159 cubic feet per acre per year,

occurring at age 60. For red alder, it is 113 cubic feet per

acre per year, occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the

use of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and may be impassable during rainy periods. Logging

roads require suitable surfacing for year-round use. Rock

for road construction is not available. Extra rock is needed

to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment and the hazard of windthrow are

the main concerns affecting timber production.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily.

When openings are made in the canopy,
the uncontrolled invasion and growth of competing plants

can prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the

seasonal high water table, trees are frequently subject to

windthrow when the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitation is the seasonal high water table. The wetness can

be reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

The main limitations on sites for septic tank absorption

fields are the very slow permeability and the seasonal high

water table. These limitations can be overcome by using

interceptor drains, by installing the absorption field at a

shallow depth, and by installing absorption lines that are

longer than normal and that are on the contour.

This map unit is in capability subclass Illw.

149--Skipopa-Blainegate complex, 0 to 8 percent

slopes. This map unit is on marine terraces characterized

by a series of elongated ridges and swales. The Skipopa

soil is on 0 to 8 percent slopes, and the Blainegate soil is

on 0 to 1 percent slopes. The native vegetation is mainly

trees and shrubs. Elevation is 20 to 200 feet. The average

annual precipitation is about 35 inches, the average annual

air temperature is about 50 degrees F, and the average

frost-free period is about 170 days.

This unit is 50 percent Skipopa silt loam and 35

percent Blainegate silty clay. The components of this

unit occur as areas so intricately intermingled that

mapping them separately was not practical at the

selected scale of mapping.

Included in this unit are small areas of Shalcar,

Edmonds, and Tromp soils and small areas of Skipopa

soils that have slopes of more than 8 percent. Included

areas make up about 15 percent of the total acreage.

The Skipopa soil is very deep and somewhat poorly

drained. It formed in loess and volcanic ash over

glaciolacustrine sediments. Typically, the surface layer is

dark brown silt loam 8 inches thick. The subsoil is 12

inches thick. In sequence downward, it is dark brown silt

loam; dark yellowish brown, mottled silt loam; and brown

and grayish brown, mottled silty clay loam. The upper 24

inches of the substratum is brown and yellowish brown,

mottled silty clay loam. The lower part to a depth of 60

inches is light brownish gray and light yellowish brown,

mottled silty clay. The depth to silty clay or silty clay loam

ranges from 14 to 24 inches. In some areas the surface

layer is loam. In other areas the substratum contains lenses

of sand or is 18 to 35 percent clay.

Permeability is very slow in the Skipopa soil. Available

water capacity is high. The effective rooting depth is limited

by a seasonal high water table, which is at a depth of 1 to

2 feet from October through June. Runoff is slow, and the

hazard of water erosion is slight.

The Blainegate soil is very deep and poorly drained. It

formed in loess and marine deposits. Typically, the surface

layer is very dark grayish brown silty clay loam 9 inches

thick. The subsoil is dark gray, mottled clay 18 inches

thick. The upper 18 inches of the substratum is gray,

mottled clay. The lower part to a depth of 60 inches is light

brownish gray, mottled clay. In some areas the surface

layer is silty clay or mucky silty clay loam. In other areas

the soil has 30 to 60 percent clay in the subsoil or

substratum or has lenses of sand in the substratum.

Permeability is very slow in the Blainegate soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is within 1

foot of the surface from November through June. Runoff

from the higher areas of the microrelief increases the

poorly drained conditions in the depressions. Runoff is very

slow, and there is no hazard of erosion.

This unit is used mainly for hay and pasture. It also is

used as woodland.

The main limitations in the areas used for hay and

pasture are the high water table and the very slow

permeability. Proper stocking rates, pasture rotation, and

restricted grazing during wet periods help to keep the

pasture in good condition. Grazing when the soils are wet

results in compaction of the surface layer and poor tilth.

The water table limits the use of this unit to grasses

unless a drainage system is installed. The wetness limits

the choice of plants and the period of cutting or grazing

and increases the risk of winterkill. Tile drains and field

ditches are needed to lower the high water table if deeprooted plants are to be grown.

Some areas have been partially drained, mainly by open

ditches, but adequate drainage systems have not been

maintained. Installing a drainage system permits fieldwork

to be conducted earlier in the spring and increases the

yields of perennial crops. The wetness can be reduced in

some areas by diversions, which intercept water, and by

open ditches, which remove excess water. The

depressions in this unit generally are not connected and

cannot be easily drained. As a result, the use of equipment

in harvesting hay is limited.

Red alder and Douglas fir are the main woodland

species. Among the trees of limited extent are western

redcedar and western hemlock. The common understory

plants are western swordfern, salmonberry, red

huckleberry, western brackenfern, trailing
blackberry, and Douglas spirea.

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

index on the Skipopa soil is 151 for Douglas fir. On the

basis of a 50-year site curve, it is 116 for Douglas fir and

97 for red alder. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 159 cubic

feet per acre per year, occurring at age 60. For red alder, it

is 113 cubic feet per acre per year, occurring at age 40.

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

index for red alder on the Blainegate soil is 85. The

highest average growth rate in unmanaged, even-aged

stands of red alder is 92 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the

use of equipment to dry periods. The use of wheeled and

tracked equipment when the soils are wet causes

excessive rutting. Using low-pressure ground equipment

can minimize damage to the soils. Unsurfaced roads are

soft when wet and may be impassable during rainy

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

Extra rock is needed to maintain a stable, uniform road

surface.

Equipment and logs on the surface result in a high

degree of compaction when the soils are moist and a high

degree of puddling when the soils are wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling mortality, seeding establishment, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting Douglas fir,

western redcedar, or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the high water table, trees are frequently subject to

windthrow when the soils are wet and winds are strong.

If this unit is used for homesite development, the main

limitation is the high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

The main limitations on sites for septic tank absorption

fields are the very slow permeability and the seasonal high

water table. These limitations can be overcome by using

interceptor drains,

by installing the absorption field at a shallow depth, and by

installing absorption lines that are longer than normal and

that are on the contour.

The Skipopa soil is in capability subclass IIIw. The

Blainegate soil is in capability subclass VIw.

150-Skykomish very gravelly loam, 3 to 30 percent

slopes. This very deep, somewhat excessively drained soil

is on outwash terraces. It formed in volcanic ash and

glacial outwash. The native vegetation is mainly conifers

and shrubs. Elevation is 1,000 to 1,400 feet. The average

annual precipitation is about 70 inches, the average annual

air temperature is about 45 degrees F, and the average

frost-free period is about 120 days.

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

leaves, and twigs 10 inches thick. When mixed to a depth

of 7 inches, the surface layer is dark yellowish brown very

gravelly loam. The subsoil also is dark yellowish brown

very gravelly loam 7 inches thick. The upper 16 inches of

the substratum is dark yellowish brown extremely gravelly

loamy sand. The lower part to a depth of 60 inches is brown

extremely gravelly sand. The depth to extremely gravelly

sand ranges from 14 to 30 inches. In some areas the

surface layer is very gravelly sandy loam or gravelly loam.

In other areas the soil has a substratum of very gravelly

sandy loam or has 15 to 35 percent rock fragments in the

subsoil and substratum.

Included in this unit are small areas of Oakes and

Cupples soils and small areas of Skykomish soils that

have slopes of more than 30 percent or less than 3

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderately rapid in the upper part of the

Skykomish soil and very rapid in the substratum. Available

water capacity is moderate. The effective rooting depth is

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

is slight.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar and red alder.

The common understory plants are red huckleberry,

western swordfern, western brackenfern, salal, and

Oregongrape.

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

index is 148 for western hemlock and 136 for Douglas fir.

On the basis of a 50-year site curve, it is 106 for western

hemlock and 108 for Douglas fir. The highest average

growth rate in unmanaged, even-aged stands of western

hemlock is 234 cubic feet per acre per year, occurring at

age 50. For Douglas fir, it is 142 cubic feet per acre per

year, occurring at age 70.

The main limitation affecting timber harvesting is
occasional snowpack. During an average year, the

snowpack limits the use of equipment and restricts access

from January through March. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Logging roads require suitable surfacing for

year-round use. Rounded pebbles and cobbles for road

construction are readily available. Cut and fill slopes tend to

ravel when dry. Steep skid trails and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling mortality and establishment are the main

concerns affecting timber production. Reforestation can be

accomplished by planting western hemlock or Douglas fir

seedlings. A low content of moisture in the surface layer

during the growing season hinders the survival of planted

and naturally established seedlings. If seed trees are

available, natural reforestation of cutover areas by western

hemlock occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can delay the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This map unit is in capability subclass IVe.

151-Snohomish silt loam, drained, 0 to 2 percent

slopes. This very deep, poorly drained soil is on flood

plains. It has been artificially drained. It formed in alluvium

underlain by organic material. The native vegetation is

mainly trees and shrubs. Elevation is 20 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 period is about 170 days.

Typically, the surface layer is dark grayish brown silt

loam 6 inches thick. The upper 11 inches of the underlying

material is dark grayish brown, mottled silt loam. The lower

part to a depth of 60 inches is dark reddish brown sapric

material. The depth to sapric material ranges from 14 to 30

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

or mucky silt loam. In other areas the soil has 10 to 18

percent clay in the underlying material, has a dark brown

surface layer, or has hemic underlying material.

Included in this unit are small areas of Puget, Oridia,

and Pangborn soils and undrained Snohomish soils.

Included areas make up about 15 percent of the total

acreage.

Permeability is moderately slow in the Snohomish soil.

Available water capacity is high. The effective rooting

depth is limited by a seasonal high water table, which is

at a depth of 1 to 3 feet from November through April.

Runoff is very slow, and there is no

hazard of erosion. In most areas this soil is subject to

occasional, brief periods of flooding from November

through April. Downstream from Lynden, however, it is

subject to frequent, brief periods of flooding from

December through February.

This unit is used mainly for hay and pasture or as

cropland. The included undrained Snohomish soils are

used as woodland.

The main limitations in the areas used for hay and

pasture are the high water table and the moderately slow

permeability. Proper stocking rates, pasture rotation, and

restricted grazing during wet periods help to keep the

pasture in good condition. Grazing when the soil is wet

results in compaction of the surface layer and poor tilth. In

areas where the drainage system is not maintained or in

areas that do not have drainage, the water table limits the

use of this unit to grasses. The wetness limits the choice of

plants and the period of cutting or grazing and increases

the risk of winterkill.

The main limitations in the areas used as cropland are

the high water table and the moderately slow permeability.

This soil is well suited to most crops commonly grown in

the survey area if adequate drainage systems are

maintained. The principal crops are peas, sweet corn,

beans, small grain, and corn silage. Tile drains and field

ditches should be maintained. They permit fieldwork to be

conducted earlier in the spring and increase the yields of

perennial crops. Drainage tile should be closely spaced

because of the moderately slow permeability. During the

growing season, the water table is artificially lowered to a

depth of about 3 to 5 feet. Subsidence is minimized if the

water table is maintained directly below the root zone

during the growing season and then allowed to return to

the surface during the winter. Using regulating structures in

open ditches as a means of subirrigation reduces the extent

of subsidence. In summer, irrigation is required for

maximum production.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, and Sitka spruce. The common understory plants

are Douglas spirea, salmonberry, rose, stinging nettle, and

sedges.

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

index for red alder is estimated to be 80. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 84 cubic feet per acre per year,

occurring at age 40.

The main limitations affecting timber harvesting are the

occasional flooding and the muddiness caused by seasonal

wetness. The use of wheeled and tracked equipment when

the soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Unsurfaced roads are soft
when wet and are subject to deep rutting during rainy

periods. Rock for road construction is not readily

available. Extra rock is needed to maintain a stable,

uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The seasonal high water table hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the high water table and the hazard of

flooding. The wetness can be reduced by building the

house on a pad and by installing drainage tile around

footings if a suitable outlet is available. If buildings are

constructed on this soil, the underlying muck should be

excavated or the buildings should be constructed on piles

anchored in the mineral soil below the muck. The design of

buildings and roads can offset the limited ability of the soil

to support a load. The main limitations on sites for septic

tank absorption fields are the hazard of flooding, the high

water table, and the moderately slow permeability.

Installing the absorption field in fill approved by the health

district helps to overcome these limitations.

This map unit is in capability subclass Ilw.

152-Snoqualmie gravelly loamy sand, 0 to 3 percent

slopes. This very deep, somewhat excessively drained

soil is on flood plains and low river terraces. It formed in

alluvium. The native vegetation is mainly trees and shrubs.

Elevation is 300 to 900 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 48 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 1 inch thick. When mixed to a depth of 6

inches, the surface layer is very dark grayish brown

gravelly loamy sand. The underlying

material to a depth of 60 inches is very dark gray and dark

gray very gravelly sand. In some areas the surface layer is

loamy sand, sandy loam, or sand. In other areas the soil

has a substratum with 15 to 35 percent rock fragments or

has strata of sandy loam.

Included in this unit are small areas of Pilchuck soils,

Riverwash, poorly drained mineral and organic soils in

drainageways, or Snoqualmie soils that have slopes of

more than 3 percent. Included areas make up about 10

percent of the total acreage.

Permeability is very rapid in the Snoqualmie soil.

Available water capacity is low. The effective rooting depth

is 60 inches. Runoff is very slow, and the hazard of water

erosion is severe because of the flooding and channeling.

A seasonal high water table is at a depth of 3 to 5 feet

from November through April. This soil is subject to

occasional, brief periods of flooding from November

through April during periods of snowmelt and rainfall.

This unit is used as woodland and for wildlife habitat.

Douglas fir is the main woodland species. Among the trees

of limited extent are red alder, western hemlock, western

redcedar, and black cottonwood. The common understory

plants are western swordfern, vine maple, red huckleberry,

trailing blackberry, bunchberry dogwood, and salmonberry.

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

index for Douglas fir is estimated to be 143. On the basis

of a 50-year site curve, it is estimated to be 110. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 149 cubic feet per acre per

year, occurring at age 65.

The main concern affecting timber harvesting is the

hazard of flooding. This limits the use of equipment to dry

periods. Generally, the surface layer is loose when dry. As

a result, the use of wheeled and tracked equipment is

limited. Logging roads require suitable surfacing for yearround use. Rounded pebbles and cobbles for road

construction are readily available.

Equipment and logs on the surface result in a

moderate degree of soil displacement when the soil is

dry. Carefully laying out roads and skid trails, properly

timing their use, and using low-pressure ground

equipment can reduce the degree of displacement.

Seedling mortality and seedling establishment are the

main concerns affecting timber production. The seedling

survival rate is reduced by droughtiness in the surface layer

and may be low in areas where flooding occurs.

Reforestation can be accomplished by planting Douglas fir

or red alder seedlings. If seed trees are available, natural

reforestation of cutover areas by red alder occurs readily.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings.
Competing vegetation can be controlled by mechanical or

chemical means.

This map unit is in capability subclass VIw.

153-Sorensen very gravelly silt loam, 8 to 30

percent slopes. This very deep, well drained soil is on

mountain back slopes and toe slopes. It formed in a

mixture of volcanic ash, loess, and colluvium derived from

glacial till. The till was derived from phyllite. The native

vegetation is mainly conifers and shrubs. Elevation is

1,000 to 1,900 feet. The average annual precipitation is

about 70 inches, the average annual air temperature is

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

about 130 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. When mixed to a depth of 7

inches, the surface layer is dark brown very gravelly silt

loam. The upper 6 inches of the subsoil is yellowish brown

very gravelly loam. The lower 13 inches is light brownish

gray very gravelly loam. The substratum to a depth of 60

inches is light olive gray very gravelly silt loam. In some

areas the surface layer is very gravelly loam or gravelly silt

loam. In other areas the soil has 15 to 35 percent rock

fragments in the subsoil and substratum or is not

dominated by phyllite rock fragments.

Included in this unit are small areas of Montborne,

Rinker, and Skykomish soils and small areas of Sorensen

soils that have slopes of more than 30 percent or less than

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

total acreage.

Permeability is moderate in the Sorensen soil.

Available water capacity is high. The effective rooting

depth is 60 inches. Runoff is slow, and the hazard of

water erosion is slight.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are red

huckleberry, western swordfern, and western brackenfern.

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

index is 134 for western hemlock and 154 for Douglas fir.

On the basis of a 50-year site curve, it is 105 for western

hemlock and 118 for Douglas fir. The highest average

growth rate in unmanaged, even-aged stands of western

hemlock is 207 cubic feet per acre per year, occurring at

age 50. For Douglas fir, it is 163 cubic feet per acre per

year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitation affecting timber harvesting is

occasional snowpack. During an average year, the

snowpack limits the use of equipment and restricts

access from January through March. Because most of the

roots are concentrated in the organic mat, loss of this layer

during logging greatly reduces natural fertility and the

available water capacity. Unsurfaced roads are soft and

slippery when wet and are subject to deep rutting during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is not readily

available. Cut and fill slopes tend to slump when wet.

Steep skid trails and firebreaks are subject to rilling and

gullying unless adequate water bars are provided or a

protective plant cover is established.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or western hemlock seedlings. If seed

trees are available, natural reforestation of cutover areas

by red alder and western hemlock occurs readily and

reforestation by Douglas fir occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass IVe.

154-Sorensen very gravelly silt loam, 30 to 60

percent slopes. This very deep, well drained soil is on

mountain back slopes and toe slopes. It formed in a

mixture of volcanic ash, loess, and colluvium derived from

glacial till. The till was derived from phyllite. The native

vegetation is mainly conifers and shrubs. Elevation is

1,000 to 1,900 feet. The average annual precipitation is

about 70 inches, the average annual air temperature is

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

about 130 days.

Typically, the surface is covered with a mat of needles

and twigs 4 inches thick. When mixed to a depth of 7

inches, the surface layer is dark brown very gravelly silt

loam. The upper 6 inches of the subsoil is yellowish brown

very gravelly loam. The lower 13 inches is light brownish

gray very gravelly loam. The substratum to a depth of 60

inches is light olive gray very gravelly silt loam. In some

areas the surface layer is very gravelly loam or gravelly silt

loam. In other areas the soil has 15 to 35 percent rock

fragments in the subsoil and substratum or is not

dominated by phyllite rock fragments.

Included in this unit are small areas of Montborne,

Rinker, and Skykomish soils and small areas of Sorensen

soils that have slopes of more than 60 percent or less

than 30 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the Sorensen soil. Available

water capacity is high. The effective rooting
depth is 60 inches. Runoff is medium, and the hazard of

water erosion is moderate.

This unit is used as woodland. Western hemlock and

Douglas fir are the main woodland species. Among the

trees of limited extent are western redcedar, red alder, and

bigleaf maple. The common understory plants are red

huckleberry, western swordfern, and western brackenfern.

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

index is 134 for western hemlock and 154 for Douglas fir.

On the basis of a 50-year site curve, it is 105 for western

hemlock and 118 for Douglas fir. The highest average

growth rate in unmanaged, even-aged stands of western

hemlock is 207 cubic feet per acre per year, occurring at

age 50. For Douglas fir, it is 163 cubic feet per acre per

year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

occasional snowpack, the hazard of erosion, and the slope.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft and slippery

when wet and are subject to deep rutting during rainy

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

available. Cut and fill slopes tend to slump when wet.

Following road construction and clearcutting, road failures

and landslides are likely. Soil creep is common on this unit.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or western hemlock seedlings. If seed

trees are available, natural reforestation of cutover areas by

red alder and western hemlock occurs readily and

reforestation by Douglas fir occurs periodically. When

openings are made in the canopy, the uncontrolled invasion

and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass VIle.

155-Springsteen very gravelly loam, 30 to 60 percent

slopes. This moderately deep, well drained soil is on high

mountain back slopes. It formed in a mixture of volcanic

ash, colluvium, and glacial till derived from phyllite. The

native vegetation is mainly conifers and shrubs. Elevation

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

about 80 inches, the average . annual air temperature is

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

about 105 days.

Typically, the surface is covered with a mat of leaves

and twigs 5 inches thick. The surface layer is brown very

gravelly loam 5 inches thick. The upper 8 inches of the

subsoil is dark yellowish brown very gravelly loam. The

lower 11 inches is dark brown very gravelly loam. Phyllite

is at a depth of about 24 inches. The depth to phyllite

ranges from 20 to 40 inches. In some areas the surface

layer is gravelly loam or very gravelly silt loam. In other

areas the soil has more than 6 percent organic carbon in

the upper part of the subsoil or is 40 to 60 inches deep to

phyllite.

Included in this unit are small areas of Wollard and

Kindy soils, soils that are 10 to 20 inches deep to phyllite,

Rock outcrop, and Springsteen soils that have slopes of

more than 60 percent or less than 30 percent. Included

areas make up about 20 percent of the total acreage.

Permeability is moderate in the Springsteen soil.

Available water capacity is low. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the

hazard of water erosion is moderate.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Douglas fir, and western redcedar.

The common understory plants are salmonberry, tall blue

huckleberry, bunchberry dogwood, deer fern, salal, and

western swordfern.

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

index for western hemlock is 137. On the basis of a 50-

year site curve, it is 96. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 213

cubic feet per acre per year, occurring at age 50.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from December through April. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less

extensively. Because most of the roots are concentrated in

the organic mat, loss of this layer during logging greatly

reduces natural fertility and the
available water capacity. Unsurfaced roads are soft and

slippery when wet and are subject to deep rutting during

rainy periods. Logging roads require suitable surfacing for

year-round use. Phyllite, a poor-quality rock for road

construction, is readily available. Cut and fill slopes tend to

slump when wet. Soil creep is common on this unit. Steep

yarding paths, skid trails, and firebreaks are subject to

rilling and gullying unless adequate water bars are provided

or a protective plant cover is established.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. If seed trees are available, natural

reforestation of cutover areas by western hemlock and

Pacific silver fir occurs periodically. Because the rooting

depth is restricted by the bedrock, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

This map unit is in capability subclass Vlle.

156-Squalicum gravelly loam, 5 to 15 percent slopes.

This deep, moderately well drained soil is on foothills and in

valleys. It formed in a mixture of volcanic ash, loess, and

slope alluvium over glacial till. The native vegetation is

mainly conifers and shrubs. Elevation is 200 to 1,500 feet.

The average annual precipitation is about 45 inches, the

average annual air temperature is about 48 degrees F, and

the average frost-free period is about 160 days.

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

leaves, and twigs 1 inch thick. When mixed to a depth of 7

inches, the surface layer is very dark grayish brown

gravelly loam. The subsoil is dark yellowish brown gravelly

loam 23 inches thick. The substratum is light olive brown

gravelly loam 14 inches thick. Dense glacial till that crushes

to gravelly loam is at a depth of 44 inches. The depth to

dense glacial till ranges from 40 to 60 inches. The dense

glacial till is similar to a cemented pan. In some areas the

surface layer is loam or gravelly silt loam. In other areas

the soil has a subsoil or substratum with 35 to 45 percent

rock fragments, is more than 60 inches deep to dense

glacial till or bedrock, is 40 to 60 inches deep over bedrock

or sand and gravel, or has dominantly phyllite or sandstone

rock fragments.

Included in this unit are small areas of Nati, Chuckanut,

Squires, Blethen, Everett, and Whatcom soils, small areas

of Bellingham and Labounty soils in depressions, soils that

are similar to the Squalicum soil but have a clayey

substratum, and Squalicum soils that

have slopes of more than 15 percent or less than 5

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the

Squalicum soil and very slow in the dense glacial till.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 3.5 to 5.0 feet from December through April.

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

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

hay and pasture and as a site for homes.

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

limitation is the hazard of erosion. Proper stocking

rates, pasture rotation, and restricted grazing during

short wet periods help to keep the pasture in good

condition and help to control runoff and erosion.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, and bigleaf maple. The common

understory plants are Oregongrape, red huckleberry,

western swordfern, vine maple, western brackenfern,

salmonberry, and willow.

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

index for Douglas fir is 176. On the basis of a 50-year site

curve, it is 132. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 187 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

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

not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means.

The main limitation affecting homesite development is

the slope. The dense glacial till is rippable and,
therefore, is not a serious limitation for most

engineering uses. The main limitations on sites for septic

tank absorption fields are the seasonal high water table, the

very slow permeability in the dense glacial till, and the

slope. These limitations can be overcome by using

interceptor drains, by installing the absorption field at a

shallow depth, and by installing absorption lines that are

longer than normal and that are on the contour. During the

rainy season, the effluent from onsite sewage disposal

systems can seep at points downslope.

This map unit is in capability subclass Ille.

157-Squalicum gravelly loam, 15 to 30 percent

slopes. This deep, moderately well drained soil is on

foothills. It formed in a mixture of volcanic ash, loess, and

slope alluvium over glacial till. The native vegetation is

mainly conifers and shrubs. Elevation is 200 to 1,500 feet.

The average annual precipitation is about 45 inches, the

average annual air temperature is about 48 degrees F, and

the average frost-free period is about 160 days.

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

leaves, and twigs 1 inch thick. The surface layer is very dark

grayish brown gravelly loam 6 inches thick. The upper 10

inches of the subsoil is dark yellowish brown gravelly loam.

The lower 27 inches is olive brown gravelly loam. Dense

glacial till that crushes to gravelly sandy loam is at a depth

of 43 inches. The depth to dense glacial till ranges from 40

to 60 inches. The dense glacial till is similar to a cemented

pan. In some areas the surface is loam or gravelly silt loam.

In other areas the soil has 35 to 45 percent rock fragments

in the subsoil, is more than 60 inches deep to dense glacial

till or bedrock, is 40 to 60 inches deep over bedrock or

sand and gravel, or has dominantly phyllite or sandstone

rock fragments.

Included in this unit are small areas of Nati, Chuckanut,

Squires, Blethen, Everett, and Whatcom soils, small areas

of Labounty soils in depressions, soils that are similar to the

Squalicum soil but have a clayey substratum, and

Squalicum soils that have slopes of more than 30 percent or

less than 15 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the upper part of the

Squalicum soil and very slow in the dense glacial till.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 3.5 to 5.0-

feet from December through April.

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

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and

bigleaf maple. The common understory plants are

Oregongrape, red huckleberry, western swordfern, vine

maple, western brackenfern, salmonberry, and willow.

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

index for Douglas fir is 176. On the basis of a 50-year site

curve, it is 132. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 187 cubic

feet per acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet causes

excessive rutting. Using low-pressure ground equipment can

minimize damage to the soil. Unsurfaced roads are soft

when wet and are subject to deep rutting during rainy

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

available. Cut and fill slopes tend to slump when wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep skid trails and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means.

This map unit is in capability subclass IVe.

158-Squalicum gravelly loam, 30 to 60 percent

slopes. This deep, moderately well drained soil is on

foothills. It formed in a mixture of volcanic ash, loess, and

slope alluvium over glacial till. The native vegetation is

mainly conifers and shrubs. Elevation is 200 to 1,500 feet.

The average annual precipitation is about 45 inches, the

average annual air temperature is about 48 degrees F, and

the average frost-free period is about 160 days.

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

leaves, and twigs 1 inch thick. The surface layer is very

dark grayish brown gravelly loam 6 inches thick. The upper

10 inches of the subsoil is dark yellowish brown gravelly

loam. The lower 27 inches is olive brown gravelly loam.

Dense glacial till that crushes to gravelly sandy loam is at a

depth of 43 inches. The
depth to dense glacial till ranges from 40 to 60 inches.

The dense glacial till is similar to a cemented pan. In some

areas the surface layer is loam or gravelly silt loam. In

other areas the soil has 35 to 45 percent rock fragments

in the subsoil, is more than 60 inches deep to dense

glacial till or bedrock, is 40 to 60 inches deep over

bedrock or sand and gravel, or has dominantly phyllite or

sandstone rock fragments.

Included in this unit are small areas of Nati, Chuckanut,

Squires, Blethen, Everett, and Whatcom soils, small areas

of Labounty soils in depressions, soils that are similar to

the Squalicum soil but have a clayey substratum, and

Squalicum soils that have slopes of more than 60 percent

or less than 30 percent. Included areas make up about 15

percent of the total acreage.

Permeability is moderate in the upper part of the

Squalicum soil and very slow in the dense glacial till.

Available water capacity is moderate or high. The

effective rooting depth is limited by a seasonal high water

table, which is at a depth of 3.5 to 5.0 feet from

December through April. Runoff is medium, and the

hazard of water erosion is moderate. Water is perched

above the dense glacial till from December through April.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are Oregongrape,

red huckleberry, western swordfern, vine maple, western

brackenfern, salmonberry, and willow.

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

index for Douglas fir is 176. On the basis of a 50-year site

curve, it is 132. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 187 cubic

feet per acre per year, occurring at age 60.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is

harvested, the slope restricts the use of wheeled and

tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less

extensively. Unsurfaced roads are soft when wet and are

subject to deep rutting during rainy periods. Logging roads

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

construction is not readily available. Cut and fill slopes tend

to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and cable yarding paths, properly timing

their use, and using cable systems that lift logs entirely off

the ground can reduce the degree of

compaction, puddling, and erosion.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This map unit is in capability subclass VIIe.

159-Squalicum-Urban land complex, 5 to 20 percent

slopes. This map unit is on foothills. The native vegetation

is mainly conifers and shrubs. Elevation is 200 to 600 feet.

The average annual precipitation is about 35 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 170 days.

This unit is 50 percent Squalicum gravelly loam and 30

percent Urban land. The components of this unit occur as

areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Chuckanut,

Everett, Labounty, Sehome, and Whatcom soils and small

areas of Squalicum soils that have slopes of more than 20

percent or less than 5 percent. Included areas make up

about 20 percent of the total acreage.

The Squalicum soil is deep and moderately well drained.

It formed in a mixture of volcanic ash, loess, and slope

alluvium over glacial till. When mixed to a depth of 7

inches, the surface layer is very dark grayish brown

gravelly loam. The subsoil is dark yellowish brown gravelly

loam 23 inches thick. The substratum is light olive brown

gravelly loam about 14 inches thick. Dense glacial till that

crushes to gravelly loam is at a depth of 44 inches. The

depth to dense glacial till ranges from 40 to 60 inches. The

dense glacial till is similar to a cemented pan. In some

areas the surface layer is loam or gravelly silt loam. In

other areas the soil has a subsoil or substratum with 35 to

45 percent rock fragments, is more than 60 inches deep to

dense glacial till or bedrock, or is 40 to 60 inches deep

over bedrock or sand and gravel.

Permeability is moderate in the upper part of the

Squalicum soil and very slow in the dense glacial till.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 3.5 to 5.0 feet from December through April.

Runoff is slow, and the hazard of water erosion is

moderate.

The Urban land consists of areas covered by streets,
buildings, parking lots, and other structures that so

obscure the soils that identification of the soil series is

not feasible.

The Squalicum soil is used for lawns, gardens, parks, or

vacant lots. It is highly erodible during construction and on

cut and fill slopes.

If this unit is used for homesite development, the main

limitation is the slope. Excavation for building sites is

limited by the dense glacial till. The dense glacial till is

rippable, however, and is not a serious limitation for most

engineering uses.

The main limitation on sites for septic tank absorption

fields is the seasonal high water table. This limitation can

be overcome by using interceptor drains, by installing the

absorption field at a shallow depth, and by installing

absorption lines that are longer than normal and that are

on the contour. The slope affects the installation of septic

tank absorption fields. During the rainy season, the effluent

from onsite sewage disposal systems can seep at points

downslope.

The Squalicum soil is in capability subclass Ille. The

Urban land is in capability subclass VIIls.

160-Squires very channery loam, 5 to 30 percent

slopes. This moderately deep, well drained soil is on back

slopes, toe slopes, and foothills. It formed in a mixture of

volcanic ash, loess, glacial till, and colluvium derived from

phyllite. The native vegetation is mainly conifers and

shrubs. Elevation is 300 to 1,400 feet. The average annual

precipitation is about 55 inches, the average annual air

temperature is about 48 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 6 inches thick. When mixed to a depth of

5 inches, the surface layer is dark brown very channery

loam. The upper 7 inches of the subsoil is dark brown very

channery loam. The lower 6 inches is dark yellowish

brown very channery loam. The substratum is light olive

brown very channery sandy loam 12 inches thick. Phyllite

is at a depth of about 30 inches. The depth to phyllite

ranges from 20 to 40 inches. In some areas the surface

layer is channery loam, channery silt loam, or very

channery silt loam. In other areas the soil has 15 to 35

percent rock fragments in the subsoil and substratum or is

40 to 60 inches deep over bedrock.

Included in this unit are small areas of Vanzandt,

Heisler, Squalicum, and Sehome soils, soils that are less

than 20 inches deep to phyllite or dense glacial till, stony

areas, Rock outcrop, and Squires soils that have slopes of

more than 30 percent or less than 5 percent. Included

areas make up about 15 percent of the total acreage.

Permeability is moderate in the Squires soil.

Available water capacity also is moderate. The effective

rooting depth is 20 to 40 inches. Runoff is slow, and the

hazard of water erosion is slight.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are western

swordfern, western brackenfern, red huckleberry,

salmonberry, vine maple, and Oregongrape.

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

index for Douglas fir is 175. On the basis of a 50-year site

curve, it is 132. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 186 cubic

feet per acre per year, occurring at age 60.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted on

this unit. Unsurfaced roads are soft and slippery when wet

and are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use. Phyllite,

a poor-quality rock for road construction, is readily

available. Cut and fill slopes tend to slump when wet. Steep

skid trails and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. A moderate reduction in

productivity can be expected to result from unmanaged fires

in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the bedrock, trees are occasionally subject to windthrow

when the soil is wet and winds are strong.

This map unit is in capability subclass IVe.

161-Squires very channery loam, 30 to 60 percent

slopes. This moderately deep, well drained soil is on low

mountain back slopes, toe slopes, and foothills. It formed in

a mixture of volcanic ash, loess, glacial till, and colluvium

derived from phyllite. The native vegetation is mainly

conifers and shrubs. Elevation is 300 to 1,400 feet. The

average annual precipitation is about 55 inches, the

average annual air temperature is about 48 degrees F, and

the average frost-free period is about 160 days.

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

leaves, and twigs 3 inches thick. The surface
layer is dark brown very channery loam 4 inches thick. The

subsoil is dark brown very channery loam 14 inches thick.

The substratum is olive brown extremely channery loam 14

inches thick. Phyllite is at a depth of about 32 inches. The

depth to phyllite ranges from 20 to 40 inches. In some

areas the surface layer is channery loam, channery silt

loam, or very channery silt loam. In other areas the soil has

15 to 35 percent rock fragments in the subsoil and

substratum or is 40 to 60 inches deep over bedrock.

Included in this unit are small areas of Vanzandt,

Heisler, Squalicum, and Sehome soils, soils that are less

than 20 inches deep to phyllite or dense glacial till, stony

areas, Rock outcrop, and Squires soils that have slopes of

more than 60 percent or less than 30 percent. Included

areas make up about 15 percent of the total acreage.

Permeability is moderate in the Squires soil. Available

water capacity also is moderate. The effective rooting depth

is 20 to 40 inches. Runoff is medium, and the hazard of

water erosion is moderate.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are western

swordfern, western brackenfern, red huckleberry,

salmonberry, vine maple, and Oregongrape.

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

index for Douglas fir is 175. On the basis of a 50-year site

curve, it is 132. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 186 cubic

feet per acre per year, occurring at age 60.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is harvested,

the slope restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Unsurfaced roads are

soft and slippery when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

surfacing for year-round use. Phyllite, a poor-quality rock for

road construction, is readily available. Cut and fill slopes

tend to slump when wet. Soil creep is common on this unit.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground reduce the hazard of erosion. A

moderate reduction in productivity can be expected to

result from unmanaged fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the bedrock, trees are occasionally subject to windthrow

when the soil is wet and winds are strong.

This map unit is in capability subclass VIle.

162-Sumas silt loam, drained, 0 to 2 percent slopes.

This very deep, poorly drained soil is on flood plains. It has

been artificially drained. It formed in recent alluvium. The

native vegetation is mainly trees and shrubs. Elevation is 20

to 50 feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface layer is dark grayish brown silt

loam 8 inches thick. The upper 18 inches of the underlying

material is grayish brown, mottled silt loam. The lower part

to a depth of 60 inches is very dark grayish brown, mottled

sand. The depth to sand ranges from 14 to 36 inches. In

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

areas the soil has a dark brown surface layer, has sandy

loam or loam in the lower part of the underlying material,

has 10 to 18 percent clay in the upper part of the

underlying material, or is 36 to 60 inches deep to sand.

Included in this unit are small areas of Puget, Shalcar,

and Briscot soils, undrained Sumas soils, and small bodies

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

total acreage.

Permeability is moderately slow in the Sumas soil.

Available water capacity is moderate. The effective

rooting depth is limited by a seasonal high water table,

which is at a depth of 1 to 3 feet from November through

April. Runoff is very slow, and there is no hazard of

erosion. In most areas this soil is subject to occasional,

brief periods of flooding from November through April.

Downstream from Lynden, however, it is subject to

frequent, brief periods of flooding from December through

February.

This unit is used mainly for hay and pasture or as

cropland. It also is used as woodland. The included

undrained Sumas soils also are used as woodland.

The main limitations in the areas used as cropland are

the high water table, the hazard of flooding, and the

moderately slow permeability. This soil is well suited to

most crops commonly grown in the survey area if adequate

drainage systems are maintained. The
principal crops are peas, sweet corn, beans, and small

grain. During the growing season, the water table is

artificially lowered to a depth of about 3 to 5 feet. Tile

drains and field ditches should be maintained. They permit

fieldwork to be conducted earlier in the spring and

increase the yields of perennial crops. In summer,

irrigation is required for maximum production.

The main limitations in the areas used for hay and

pasture are the high water table, the hazard of flooding,

and the moderately slow permeability. Proper stocking

rates, pasture rotation, and restricted grazing during wet

periods help to keep the pasture in good condition.

Grazing when the soil is wet results in compaction of the

surface layer and poor tilth. In areas where the drainage

system is not maintained or in areas that do not have

drainage, the water table limits the use of this unit to

grasses. The wetness limits the choice of plants and the

period of cutting or grazing and increases the risk of

winterkill.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, and black cottonwood. The common understory

plants are salmonberry, Douglas spirea, rose, stinging

nettle, and sedges.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitations affecting timber harvesting are the

occasional flooding and the muddiness caused by seasonal

wetness. The use of wheeled and tracked equipment when

the soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Unsurfaced roads are soft when wet and are subject to

deep rutting during rainy periods. Rock for road

construction is not readily available. Extra rock is needed

to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The seasonal high water table hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitations are the high water table and the hazard of

flooding. The wetness can be reduced by building the

house on a pad and by installing drainage tile around

footings if a suitable outlet is available. In shallow

excavations special retainer walls may be needed to keep

cutbanks from caving. The main limitations on sites for

septic tank absorption fields are the high water table and

the hazard of flooding.

This map unit is in capability subclass Ilw.

163-Tacoma silt loam, 0 to 1 percent slopes. This

very deep, very poorly drained soil is on flood plains,

deltas, and tidal flats. It formed in alluvium. The native

vegetation is mainly trees and shrubs. Elevation is sea

level to 20 feet above sea level. The average annual

precipitation is about 35 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 185 days.

Typically, the surface layer is dark grayish brown,

mottled silt loam 11 inches thick. The upper 7 inches of the

underlying material is dark grayish brown, mottled silt loam.

The next 30 inches is dark gray, mottled silt loam. The

lower part to a depth of 60 inches is dark gray, mottled

very fine sandy loam. In some areas the surface layer is

very fine sandy loam. In other areas the soil has 18 to 35

percent clay in the upper part of the underlying material; is

30 to 40 inches deep to fine sandy loam or sand; or is

stratified silt loam, sandy loam, and sand from 20 to 60

inches.

Included in this unit are small areas of drained

Tacoma soils, organic soils in depressions subject to

ponding, and small bodies of water. Included areas

make up about 10 percent of the total acreage.

Permeability is moderately slow in the Tacoma soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at or

above the surface from November through April. Runoff is

very slow, and there is no hazard of erosion. This soil is

subject to frequent, long periods of flooding from

December through April. It is subject to tidal inundation

unless protected.

This unit is used mainly as woodland or for wildlife

habitat. Red alder is the main woodland species. Among

the trees of limited extent are western redcedar, western

hemlock, black cottonwood, and Sitka spruce.
The common understory plants are willow, western

brackenfern, western swordfern, devilsclub, Indian plum,

salmonberry, and Douglas spirea.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitations affecting timber harvesting are the

muddiness caused by seasonal wetness and the hazard of

flooding. These limit the use of equipment to dry periods.

Unsurfaced roads are soft and slippery when wet and may

be impassable during rainy periods. Rock for road

construction is not readily available. Extra rock is needed

to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, the hazard of

windthrow, and plant competition are the main concerns

affecting timber production. The high water table hinders

root respiration and thus results in a low seedling survival

rate. Reforestation can be accomplished by planting red

alder or western redcedar seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the high water table, trees are frequently subject to

windthrow when the soil is wet and winds are strong. The

survival rate of seedlings may be low in areas where

flooding occurs.

This map unit is in capability subclass VIw.

164-Tacoma silt loam, drained, 0 to 1 percent

slopes. This very deep, very poorly drained soil is on flood

plains, deltas, and tidal flats. It has been artificially drained.

It formed in alluvium. The native vegetation is mainly trees

and shrubs. Elevation is sea level to 20 feet above sea

level. The average annual precipitation is about 35 inches,

the average annual air temperature is about 50 degrees F,

and the average frost-free period is about 185 days.

Typically, the surface layer is dark grayish brown,

mottled silt loam 7 inches thick. The upper 5 inches of the

underlying material is dark grayish brown, mottled silt

loam. The next 23 inches is dark gray, mottled silt

loam. The lower part to a depth of 60 inches is dark gray,

mottled very fine sandy loam. In some areas the surface

layer is very fine sandy loam. In other areas the soil has 18

to 35 percent clay in the upper part of the underlying

material; is 30 to 40 inches deep to fine sandy loam or

sand; or is stratified silt loam, sandy loam, and sand from

20 to 60 inches.

Included in this unit are small areas of undrained

Tacoma soils and small areas of Shalcar soils, which are

in depressions and are subject to ponding. Also included

are small bodies of water. Included areas make up about

10 percent of the total acreage.

Permeability is moderately slow in the Tacoma soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 1.0 to 2.5 feet from November through April.

Runoff usually is very slow, but the soil may be ponded

during the winter. There is no hazard of erosion. This soil is

subject to frequent, brief periods of flooding from November

through April. It is subject to tidal inundation unless

protected.

This unit is used for hay and pasture or as cropland.

The main limitations in the areas used for hay and

pasture are the high water table, the hazard of flooding, the

moderately slow permeability, and the influence of salt.

Proper stocking rates, pasture rotation, and restricted

grazing during wet periods help to keep the pasture in good

condition. Grazing when the soil is wet results in

compaction of the surface layer and poor tilth. In areas

where the drainage system is not maintained or in areas

that do not have drainage, the water table limits the use of

this unit to grasses and shallow-rooted legumes. The

wetness limits the choice of plants and the period of cutting

or grazing and increases the risk of winterkill Field ditches,

tile lines, and pumping stations are used to lower the water

table and leach out salts. Using regulating structures in

open ditches as a means of subirrigation can reduce the

high acidity in the lower part of the underlying material.

The main limitations in the areas used as cropland are

the high water table, the hazard of flooding, the moderately

slow permeability, and the influence of salt. This soil is well

suited to most crops commonly grown in the survey area if

adequate drainage systems are maintained. The principal

crops are peas, sweet corn, and small grain. Returning all

crop residue to the soil and including grasses, legumes, or

grass-legume mixtures in the cropping sequence help to

maintain fertility and tilth. During the growing season, the

water table is artificially lowered to a depth of about 3 to 5

feet. Tile drains and field ditches should be maintained.

They permit fieldwork to be conducted earlier in the spring

and increase the yields of perennial crops. Installing tile

drains no deeper than 30 inches minimizes
the effects of the salt. Drainage tiles should be closely

spaced because of the restricted permeability. In summer,

irrigation is required for maximum production.

If this unit is used for homesite development, the main

limitations are the high water table and the hazard of

flooding. The wetness can be reduced by building the

house on a pad and by installing drainage tile around

footings if a suitable outlet is available. The main

limitations on sites for septic tank absorption fields are the

high water table, the moderately slow permeability, and the

hazard of flooding. Installing absorption lines that are

longer than normal helps to overcome these limitations.

This map unit is in capability subclass IIIw.

165-Tromp loam, 0 to 2 percent slopes. This very

deep, moderately well drained soil is on outwash terraces.

It formed in a mixture of loess and volcanic ash over glacial

outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 50 to 300 feet. The average annual

precipitation is about 45 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

Typically, the surface layer is dark brown loam 11 inches

thick. The upper 9 inches of the subsoil is dark brown and

strong brown loam. The lower 6 inches is weakly

cemented, dark yellowish brown, mottled sandy loam. The

upper 20 inches of the substratum is weakly cemented,

olive brown, mottled sand. The lower part to a depth of 60

inches is grayish brown and dark grayish brown, mottled

sand. The depth to sand ranges from 14 to 30 inches. In

some areas the surface layer is sandy loam or silt loam. In

other areas the soil is not cemented, is sandy loam in the

upper part of the substratum, has 15 to 35 percent pebbles

in the substratum, has loamy glaciomarine or glacial till at a

depth of 40 to 60 inches, or is 10 to 14 inches deep to

sand.

Included in this unit are small areas of Hale, Yelm,

Edmonds, Lynden, Birchbay, and Whatcom soils and

small areas of Tromp soils that are subject to occasional

flooding. Included areas make up about 15 percent of the

total acreage.

Permeability is moderate in the upper part of the

Tromp soil and very rapid in the substratum. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a

depth of 1.5 to 2.5 feet from November through April.

Runoff is very slow, and there is no hazard of erosion.

This unit is used mainly for hay and pasture, as

cropland, or as woodland. It also is used as a site for

homes.

The main limitation in the areas used for hay and

pasture is the seasonal high water table. Proper stocking

rates, pasture rotation, and restricted grazing during wet

periods help to keep the pasture in good condition.

This unit has few limitations in the areas used for

cropland. The principal crops are raspberries,

strawberries, and sweet corn. In summer, irrigation is

required for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder, and

western redcedar. The common understory plants are

western swordfern, salal, Oregongrape, red huckleberry,

vine maple, and western brackenfern.

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

index for Douglas fir is 129. On the basis of a 50-year site

curve, it is 100. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 128 cubic

feet per acre per year, occurring at age 70.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet

causes excessive rutting. Using low-pressure ground

equipment can minimize damage to the soil. Unsurfaced

roads are soft when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

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

not readily available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the seasonal high water table, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

The main limitation affecting homesite development is

the seasonal high water table. The main limitations on

sites for septic tank absorption fields are the seasonal high

water table and a poor filtering capacity in the substratum.

Installing the absorption field in fill approved by the health

district helps to overcome these limitations.

This map unit is in capability subclass llw.
166-Twinsi very gravelly loam, 30 to 60 percent

slopes. This moderately deep, moderately well drained soil

is on high mountain shoulder slopes and back slopes. It

formed in colluvium and glacial till with an admixture of

volcanic ash and loess. The colluvium and glacial till are

derived from dunite. The native vegetation is mainly

conifers and shrubs. Elevation is 2,500 to 4,000 feet. The

average annual precipitation is about 95 inches, the

average annual air temperature is about 41 degrees F, and

the average frost-free period is about 95 days.

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

twigs, and bark 8 inches thick. When mixed to a depth of 6

inches, the surface layer is strong brown very gravelly

loam. The upper 8 inches of the subsoil is strong brown

very gravelly loam. The lower 8 inches is dark yellowish

brown very gravelly loam. The substratum is grayish brown

very gravelly sandy loam 5 inches thick. Dense glacial till

that crushes to very gravelly loam is at a depth of 27

inches. The depth to dense glacial till ranges from 20 to 40

inches. The dense glacial till is similar to a cemented pan.

In some areas the surface layer is very gravelly silt loam or

gravelly loam. In other areas the soil is 40 to 60 inches

deep to dense glacial till or dunite.

Included in this unit are small areas of Edfro, Jackman,

and Klawatti soils, soils that are shallow over bedrock,

Rock outcrop, and Twinsi soils that have slopes of more

than 60 percent or less than 30 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the Twinsi

soil and very slow in the dense glacial till. Available water

capacity is moderate. The effective rooting depth is 20 to

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

erosion is moderate. Water is perched above the dense

glacial till from November through April.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Alaska cedar, and mountain hemlock.

The common understory plants are tall blue huckleberry,

bunchberry dogwood, western brackenfern, deer fern, and

longtube twinflower. Vegetation is somewhat stunted and

sparse because of the toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through May. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces natural

fertility and the available water capacity. Unsurfaced roads

are soft and slippery when wet and are subject to deep

rutting during rainy periods. Logging roads require suitable

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

not readily available. Cut and fill slopes tend to slump when

wet. Following road construction and clearcutting, road

failures and landslides are likely. Soil creep is common on

this unit.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Steep yarding paths, skid trails, and firebreaks are subject

to rifling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of

other important minerals, and a low content of moisture in

the surface layer during the growing season hinder the

survival of planted and naturally established seedlings. A

low soil temperature, deep snowpack, and a short growing

season also hinder the survival of the seedlings and delay

their establishment. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock, Pacific silver fir, or Alaska cedar seedlings, which

are adapted to the toxicity of dunite soils. If seed trees are

available, natural reforestation of cutover areas by western

hemlock, Pacific silver fir, and Alaska cedar occurs

periodically. Trees grow poorly and lack vigor on soils that

are derived from dunite. Planting seedlings in the organic

layer improves growth and vigor. Because the rooting

depth is restricted by the dense glacial till, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIle.

167-Twinsi very stony loam, 30 to 60 percent

slopes. This moderately deep, moderately well drained

soil is on high mountain shoulder slopes and back slopes.

It formed in colluvium and glacial till with an
admixture of volcanic ash and loess. The colluvium and

glacial till are derived from dunite. The native vegetation is

mainly conifers and shrubs. Elevation is 2,500 to 4,000

feet. The average annual precipitation is about 95 inches,

the average annual air temperature is about 41 degrees F,

and the average frost-free period is about 95 days.

Typically, the surface is covered with a mat of needles

and twigs 6 inches thick. When mixed to a depth of 6

inches, the surface layer is dark brown very stony loam.

The subsoil is strong brown extremely gravelly loam 19

inches thick. Dense glacial till that crushes to very gravelly

sandy loam is at a depth of 25 inches. The depth to dense

glacial till ranges from 20 to 40 inches. The dense glacial

till is similar to a cemented pan. In some areas the surface

layer is very gravelly loam or very gravelly silt loam. In

other areas the soil is 40 to 60 inches deep to dense

glacial till or dunite.

Included in this unit are small areas of Edfro, Jackman,

and Kiawatti soils, soils that are shallow over bedrock,

Rock outcrop, and Twinsi soils that have slopes of more

than 60 percent or less than 30 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the Twinsi

soil and very slow in the dense glacial till. Available water

capacity is moderate. The effective rooting depth is 20 to

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

erosion is moderate. Water is perched above the dense

glacial till from November through April.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, Alaska cedar, and mountain hemlock.

The common understory plants are tall blue huckleberry,

bunchberry dogwood, western brackenfern, deer fern, and

longtube twinflower. Vegetation is somewhat stunted and

sparse because of the toxicity of the dunite-derived soil.

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

index for western hemlock is estimated to be 77. On the

basis of a 50-year site curve, it is estimated to be 55. The

highest average growth rate in unmanaged, even-aged

stands of western hemlock is about 84 cubic feet per acre

per year, occurring at age 60. Areas on ridgetops that are

subject to strong, persistent winds are less productive than

the other areas of this unit.

The main limitations affecting timber harvesting are

snowpack, the slope, the surface stones, and the hazard of

erosion. The trees can break if they are felled on the

stones, and yarding operations can be hindered by the

stones. During an average year, the snowpack limits the

use of equipment and restricts access from November

through May. When timber is harvested, the

slope restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Because most of the

roots are concentrated in the organic mat, loss of this layer

during logging greatly reduces natural fertility and the

available water capacity. Unsurfaced roads are soft and

slippery when wet and are subject to deep rutting during

rainy periods. Logging roads require suitable surfacing for

year-round use. Rock for road construction is not readily

available. Cut and fill slopes tend to slump when wet.

Following road construction and clearcutting, road failures

and landslides are likely. Soil creep is common on this

unit.

Carefully laying out roads and cable yarding paths,

properly timing their use, and using cable systems that lift

logs entirely off the ground reduce the hazard of erosion.

Steep yarding paths, skid trails, and firebreaks are subject

to rilling and gullying unless adequate water bars are

provided or a protective plant cover is established.

Seedling mortality is the main concern affecting timber

production. A high content of magnesium in relation to

calcium, a high content of iron, a low concentration of

other important minerals, and a low content of moisture in

the surface layer during the growing season hinder the

survival of planted and naturally established seedlings. A

low soil temperature, deep snowpack, and a short growing

season also hinder the survival of the seedlings and delay

their establishment. The seedling mortality rate is higher

on ridgetops that are subject to strong, persistent winds

than in other areas of this unit.

Reforestation can be accomplished by planting western

hemlock, Pacific silver fir, or Alaska cedar seedlings,

which are adapted to the toxicity of dunite soils. Because

of the abundance of surface stones, planting seedlings by

hand is difficult. If seed trees are available, natural

reforestation of cutover areas by western hemlock, Pacific

silver fir, and Alaska cedar occurs periodically. Trees grow

poorly and lack vigor on soils that are derived from dunite.

Planting seedlings in the organic layer improves growth

and vigor. Because the rooting depth is restricted by the

dense glacial till, trees are occasionally subject to

windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass VIle.

168-Typic Cryorthods, 60 to 90 percent slopes.

These moderately deep to very deep, well drained soils

are on high mountainsides and ridges. They formed in

colluvium derived dominantly from glacial till, volcanic ash,

and residuum from sandstone. The native vegetation is

mainly conifers and shrubs. Elevation is 2,600 to 3,600

feet. The average annual precipitation is
about 85 inches, the average annual air temperature is

about 42 degrees F, and the average frost-free period is

about 100 days.

No single profile is representative of these soils. In one

of the more commonly observed ones, however, the

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

about 2 inches thick. When mixed to a depth of 9 inches,

the surface layer is dark yellowish brown loam. The upper

26 inches of the subsoil is dark yellowish brown loam. The

lower 11 inches is dark brown loam. The substratum to a

depth of 60 inches is yellowish brown loam. The content of

weathered rock fragments ranges from 35 to 60 percent

throughout this profile. The texture, the content of rock

fragments, and the depth to dense glacial till or bedrock

vary widely within short distances. Much of the unit is

underlain by dense glacial till at a depth of more than 40

inches. The depth to bedrock is more than 20 inches. The

content of rock fragments in the particle-size control section

ranges from 0 to 30 percent by weighted average. The

content of weathered rock fragments ranges from 25 to 60

percent by weighted average. The part of the profile having

properties associated with weathered volcanic ash is 10 to

more than 60 inches thick.

Included in this unit are small areas of Getchell,

Potchub, Gallup, Saar, Crinker, and Hartnit soils, soils

that are less than 20 inches deep over bedrock or dense

glacial till, slumps, stony areas, Rock outcrop, and Typic

Cryorthods that have slopes of less than 60 percent.

Included areas make up about 20 percent of the total

acreage.

Permeability is moderate in the Typic Cryorthods.

Available water capacity is moderate or high. The effective

rooting depth is more than 20 inches. Runoff is rapid, and

the hazard of water erosion is severe.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, western redcedar, and mountain

hemlock. The common understory plants are red

huckleberry, blueleaved huckleberry, salal, longtube

twinflower, salmonberry, and bunchberry dogwood.

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

index for western hemlock is 110. On the basis of a 50-

year site curve, it is 78. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 160

cubic feet per acre per year, occurring at age 55. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.

The main limitations affecting timber harvesting are the

slope, snowpack, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from November through April. Cable

yarding systems generally are used on this

unit. When timber is harvested, the slope restricts the use

of wheeled and tracked skidding equipment. Cable yarding

systems generally are safer and disturb the surface less

extensively. Because most of the roots are concentrated in

the organic mat, loss of this layer during logging greatly

reduces natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and

are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use. Rock

for road construction is generally not readily available. Cut

and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. The areas underlain by dense glacial till are most

prone to landslides. Soil creep is common on this unit.

Locating roads on midslopes requires extensive cutting and

filling, which remove land from production.

Steep yarding paths, skid trails, and firebreaks are

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground reduce the hazard of erosion. A

moderate reduction in productivity can be expected to

result from unmanaged fires in undisturbed areas.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. Because of the slope, planting by hand is

difficult. If seed trees are available, natural reforestation of

cutover areas by western hemlock and Pacific silver fir

occurs periodically. Because the rooting depth is restricted

by the dense glacial till or bedrock in some areas, trees

are occasionally subject to windthrow when the soils are

wet and winds are strong.

This map unit is in capability subclass VIle.

169-Typic Cryorthods-Rock outcrop complex, 60 to

90 percent slopes. This map unit is on high

mountainsides and ridges. The native vegetation is mainly

conifers and shrubs. Elevation is 2,600 to 3,600 feet. The

average annual precipitation is about 85 inches, the

average annual air temperature is about 42 degrees F,

and the average frost-free period is about 100 days.

This unit is 65 percent Typic Cryorthods and 20
percent Rock outcrop. The components of this unit occur

as areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Getchell,

Potchub, Gallup, Saar, Crinker, and Hartnit soils, soils

that are less than 20 inches deep over bedrock or dense

glacial till, slumps, stony areas, and Typic Cryorthods that

have slopes of less than 60 percent. Included areas

make up about 15 percent of the total acreage.

The Typic Cryorthods are moderately deep to very deep

and well drained. They formed in colluvium derived

dominantly from glacial till, volcanic ash, and residuum

from sandstone. No single profile is representative of these

soils. In one of the more commonly observed ones,

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

leaves, and twigs about 6 inches thick. When mixed to a

depth of 6 inches, the surface layer is organic stained, dark

yellowish brown loam. The subsoil is olive brown loam 18

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

light olive brown loam. The content of weathered rock

fragments ranges from 35 to 60 percent throughout this

profile. The texture, the content of rock fragments, and the

depth to dense glacial till or bedrock vary widely within

short distances. Much of the unit is underlain by dense

glacial till at a depth of more than 40 inches. The depth to

bedrock is more than 20 inches. The content of rock

fragments in the particle-size control section ranges from 0

to 30 percent by weighted average. The content of

weathered rock fragments ranges from 25 to 60 percent by

weighted average. The part of the profile having properties

associated with weathered volcanic ash is 10 to more than

60 inches thick.

Permeability is moderate in the Typic Cryorthods.

Available water capacity is moderate or high. The effective

rooting depth is more than 20 inches. Runoff is rapid, and

the hazard of water erosion is severe.

Typically, the Rock outcrop is sandstone or

metasedimentary rock. It is hard and generally

unweathered. It occurs as steep cliffs and irregular

formations.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir, western redcedar, and mountain

hemlock. The common understory plants are red

huckleberry, blueleaved huckleberry, salal, longtube

twinflower, salmonberry, and bunchberry dogwood.

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

index for western hemlock is 110. On the basis of a 50-

year site curve, it is 78. The highest average growth rate in

unmanaged, even-aged stands of western

hemlock is 160 cubic feet per acre per year, occurring at

age 55. Yields are reduced by the extent of the Rock

outcrop. Areas on ridgetops that are subject to strong,

persistent winds are less productive than the other areas of

this unit.

The main limitations affecting timber harvesting are the

slope, the Rock outcrop, snowpack, and the hazard of

erosion. The trees can break if they are felled on the Rock

outcrop. During an average year, the snowpack limits the

use of equipment and restricts access from November

through April. The pattern of the Rock outcrop on the

landscape results in a discontinuous slope, which hinders

the use of cable yarding systems. These systems generally

are used on this unit. When timber is harvested, the slope

restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Because most of the

roots are concentrated in the organic mat, loss of this layer

during logging greatly reduces natural fertility and the

available water capacity.

Unsurfaced roads are soft and slippery when wet and

are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use. Rock

for road construction is generally not readily available. Cut

and fill slopes tend to slump when wet. Following road

construction and clearcutting, road failures and landslides

are likely. The areas underlain by dense glacial till are

most prone to landslides. Soil creep is common on this

unit. Locating roads on midslopes requires extensive

cutting and filling, which remove land from production.

Because of the Rock outcrop, yarding and skidding

paths converge. This convergence results in compaction of

the underlying soil. Steep yarding paths, skid trails, and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established. Carefully laying out roads and cable

yarding paths, properly timing their use, and using cable

systems that lift logs entirely off the ground reduce the

hazard of erosion. A moderate reduction in productivity can

be expected to result from unmanaged fires in undisturbed

areas.

Seedling mortality and the hazard of windthrow are the

main concerns affecting timber production. A low soil

temperature, deep snowpack, and a short growing season

hinder the survival of planted and natural seedlings and

delay their establishment. The seedling mortality rate is

higher on ridgetops that are subject to strong, persistent

winds than in other areas of this unit. Reforestation can be

accomplished by planting western hemlock or Pacific silver

fir seedlings. Because of the slope, planting by hand is

difficult. If seed trees are
available, natural reforestation of cutover areas by western

hemlock and Pacific silver fir occurs periodically. The Rock

outcrop prevents the even distribution of reforestation.

Because the rooting depth is restricted by the dense glacial

till and bedrock in some areas, trees are occasionally

subject to windthrow when the soils are wet and winds are

strong.

The Typic Cryorthods are in capability subclass VIle.

The Rock outcrop is in capability subclass Vllls.

170-Typic Psammaquents, tidal, 0 to 1 percent

slopes. These very deep, poorly drained soils are on tidal

flats. They formed in alluvium. The average annual

precipitation is about 35 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days. Elevation is sea level.

No single profile is representative of these soils. In one

of the more commonly observed ones, however, the soil to

a depth of 60 inches is gray and olive gray loamy sand and

sand. The sand content ranges from 80 to 95 percent. The

content of clay ranges from 0 to 2 percent. In some areas

the soil has strata of sandy loam.

Included in this unit are small areas of water and

Hydraquents. Included areas make up about 10 percent of

the total acreage.

Permeability is very rapid in the Typic Psammaquents.

Available water capacity is low. The effective rooting depth

is limited by a seasonal high water table, which is at or

above the surface during periods of high tide. These soils

are subject to frequent, long periods of flooding during high

tides throughout the year.

This unit is used as wildlife habitat or for recreation.

This map unit is in capability subclass VIIIw.

171-Urban land. This map unit is on terraces. Slopes

are 0 to 3 percent. Elevation is near sea level to 220 feet

above sea level. The average annual precipitation is about

35 inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

The Urban land consists of areas covered by streets,

buildings, parking lots, and other structures that so obscure

the soils that identification of the soil series is not feasible.

Included in this unit are small areas of Labounty,

Whatcom, Whitehorn, Birchbay, Everett, and Squalicum

soils and small areas of Urban land that have slopes of

more than 3 percent. Included areas make up about 10

percent of the total acreage.

This unit is used for urban development. This

map unit is in capability subclass Vllls.

172-Urban land-Whatcom-Labounty complex, 0 to 8

percent slopes. This map unit is on glaciomarine drift

plains. The Whatcom soil is on 0 to 8 percent slopes, and

the Labounty soil is on 0 to 2 percent slopes. The native

vegetation is mainly trees and shrubs. Elevation is near

sea level to 200 feet above sea level. The average annual

precipitation is about 35 inches, the average annual air

temperature is about 50 degrees F, and the average frostfree period is about 170 days.

This unit is 40 percent Urban land, 30 percent

Whatcom silt loam, and 20 percent Labounty silt loam.

The components of this unit occur as areas so intricately

intermingled that mapping them separately was not

practical at the selected scale of mapping.

Included in this unit are small areas of Squalicum,

Bellingham, Everett, Birchbay, Chuckanut, and Kickerville

soils and small areas of Whatcom soils that have slopes

of more than 8 percent. Included areas make up about 10

percent of the total acreage.

The Urban land consists of areas covered by streets,

buildings, parking lots, and other structures that so obscure

the soils that identification of the soil series is not feasible.

The Whatcom soil is very deep and moderately well

drained. It formed in a mixture of loess and volcanic ash

over glaciomarine deposits. Typically, the surface layer is

dark brown silt loam 9 inches thick. The upper 7 inches of

the subsoil is dark brown silt loam. The lower 10 inches is

light olive brown, mottled loam. The upper 9 inches of the

substratum is olive gray, mottled loam. The lower part to a

depth of 60 inches is dark gray loam. In some areas the

surface layer is loam or gravelly silt loam. In other areas

the substratum has lenses of sandy material, is 10 to 18

percent clay, or is 5 to 10 percent cobbles, stones, or

boulders.

Permeability is moderate in the upper part of the

Whatcom soil and slow in the lower part. Available water

capacity is high. The effective rooting depth is limited by

a seasonal high water table, which is at a depth of 1.5

to 3.0 feet from December through April. Runoff is slow,

and the hazard of water erosion is slight.

The Labounty soil is very deep and poorly drained. It

formed in an admixture of loess, volcanic ash, and

glaciomarine deposits. Typically, the surface layer is very

dark grayish brown silt loam 10 inches thick. The upper 6

inches of the subsoil is grayish brown and light brownish

gray, mottled loam. The lower 19 inches is grayish brown,

olive gray, and light olive gray, mottled loam. The

substratum to a depth of 60 inches is gray loam. In some

areas the surface layer is loam. In other areas the

substratum has lenses of sandy material, is 10 to 18

percent clay, or is 5 to 10 percent cobbles, stones, or

boulders.
Permeability is moderately slow in the Labounty soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 1 to 3 feet from November through May. Runoff

usually is very slow, but the soil may be ponded during the

winter. There is no hazard of erosion.

The Whatcom and Labounty soils in this unit are

used for lawns, gardens, parks, or vacant lots.

The main limitation affecting homesite development is

the high water table. Tile drains and open drains can be

used to lower the water table if a suitable outlet is

available. The wetness can be reduced by building the

house on a pad and by installing drainage tile around

footings if a suitable outlet is available. The restricted

permeability and the high water table increase the

likelihood that the absorption field will fail. Installing

absorption lines that are longer than normal helps to

overcome these limitations.

The Urban land is in capability subclass VIlls. The

Whatcom soil is in capability subclass lIe. The Labounty

soil is in capability subclass Ilw.

173-Vanzandt very gravelly loam, 5 to 15 percent

slopes. This moderately deep, moderately well drained soil

is on foothill toe slopes and in valleys. It formed in

volcanic ash, loess, and slope alluvium over glacial till

derived dominantly from phyllite. The native vegetation is

mainly conifers and shrubs. Elevation is 250 to 1,500 feet.

The average annual precipitation is about 60 inches, the

average annual air temperature is about 47 degrees F,

and the average frost-free period is about 160 days.

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

leaves, and twigs 1 inch thick. When mixed to a depth of 7

inches, the surface layer is dark brown very gravelly loam.

The subsoil is dark yellowish brown and dark brown very

gravelly loam 16 inches thick. The substratum is light

yellowish brown, mottled very gravelly loam about 8 inches

thick. Dense glacial till that crushes to very gravelly loam is

at a depth of 31 inches. The depth to dense glacial till

ranges from 20 to 40 inches. The dense glacial till is

similar to a cemented pan. In some areas the surface layer

is gravelly loam or very gravelly silt loam. In other areas

the soil has 15 to 35 percent rock fragments in the subsoil

and the upper part of the substratum or is 40 to 60 inches

deep to dense glacial till.

Included in this unit are small areas of Squires, Heisler,

and Barneston soils; Bellingham and Shalcar soils in

depressions; soils that have a substratum of very gravelly

sand; and Vanzandt soils that have slopes of more than 15

percent or less than 5 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Vanzandt soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is slow, and the hazard of

water erosion is slight. Water is perched above the dense

glacial till from December through April.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

red alder, western hemlock, western redcedar, and bigleaf

maple. The common understory plants are Oregongrape,

western swordfern, western brackenfern, vine maple, salal,

red huckleberry, and salmonberry.

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

index for Douglas fir is 159. On the basis of a 50-year site

curve, it is 125. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 169 cubic

feet per acre per year, occurring at age 65.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted

on this unit. Unsurfaced roads are soft and slippery when

wet and are subject to deep rutting during rainy periods.

Logging roads require suitable surfacing for year-round

use. Rock for road construction is not readily available.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of

competing plants can prevent the establishment of

seedlings. Competing vegetation can be controlled by

mechanical or chemical means. Because the rooting depth

is restricted by the dense glacial till, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

This map unit is in capability subclass IVe.

174-Vanzandt very gravelly loam, 15 to 30

percent slopes. This moderately deep, moderately well

drained soil is on foothill back slopes and toe slopes. It

formed in volcanic ash, loess, and slope alluvium over

glacial till derived dominantly from phyllite. The native

vegetation is mainly conifers and shrubs. Elevation is 250

to 1,500 feet. The average annual precipitation is about 60

inches, the average annual air temperature is about 47

degrees F, and the average frost-free period is about 160

days.

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

leaves, and twigs 2 inches thick. When mixed to a depth

of 8 inches, the surface layer is dark brown very gravelly

loam. The subsoil is strong brown very gravelly loam 11

inches thick. The substratum is light
olive brown and grayish brown very gravelly loam 20

inches thick. Dense glacial till that crushes to very gravelly

loam is at a depth of 39 inches. The depth to dense glacial

till ranges from 20 to 40 inches. The dense glacial till is

similar to a cemented pan. In some areas the surface

layer is gravelly loam or very gravelly silt loam. In other

areas the soil has 15 to 35 percent rock fragments in the

subsoil and the upper part of the substratum or is 40 to 60

inches deep to dense glacial till.

Included in this unit are small areas of Squires, Heisler,

and Barneston soils; Bellingham and Shalcar soils in

depressions; soils that have a substratum of very gravelly

sand; and Vanzandt soils that have slopes of more than 30

percent or less than 15 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Vanzandt soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is slow, and the hazard of

water erosion is slight. Water is perched above the dense

glacial till from December through April.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

red alder, western hemlock, western redcedar, and bigleaf

maple. The common understory plants are Oregongrape,

western swordfern, western brackenfern, vine maple, salal,

red huckleberry, and salmonberry.

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

index for Douglas fir is 159. On the basis of a 50-year site

curve, it is 125. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 169 cubic

feet per acre per year, occurring at age 65.

The kind of equipment that can be used and the time of

the year when it can be used normally are not restricted on

this unit. Unsurfaced roads are soft and slippery when wet

and are subject to deep rutting during rainy periods.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is not readily available. Cut and

fill slopes tend to slump when wet. Steep skid trails and

firebreaks are subject to rilling and gullying unless adequate

water bars are provided or a protective plant cover is

established.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

Because the rooting depth is restricted by the dense

glacial till, trees are occasionally subject to windthrow

when the soil is wet and winds are strong.

This map unit is in capability subclass IVe.

175-Vanzandt very gravelly loam, 30 to 60 percent

slopes. This moderately deep, moderately well drained soil

is on low mountain back slopes and toe slopes. It formed

in volcanic ash, loess, and slope alluvium over glacial till

derived dominantly from phyllite. The native vegetation is

mainly conifers and shrubs. Elevation is 250 to 1,500 feet.

The average annual precipitation is about 60 inches, the

average annual air temperature is about 47 degrees F,

and the average frost-free period is about 160 days.

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

leaves, and twigs 2 inches thick. When mixed to a depth of

8 inches, the surface layer is dark brown very gravelly

loam. The subsoil is strong brown very gravelly loam 11

inches thick. The substratum is light olive brown and

grayish brown very gravelly loam 20 inches thick. Dense

glacial till that crushes to very gravelly loam is at a depth of

39 inches. The depth to dense glacial till ranges from 20 to

40 inches. The dense glacial till is similar to a cemented

pan. In some areas the surface layer is gravelly loam or

very gravelly silt loam. In other areas the soil has 15 to 35

percent rock fragments in the subsoil and the upper part of

the substratum or is 40 to 60 inches deep to glacial till.

Included in this unit are small areas of Squires, Heisler,

and Barneston soils; Bellingham and Shalcar soils in

depressions; soils that have a substratum of very gravelly

sand; and Vanzandt soils that have slopes of more than 60

percent or less than 30 percent. Included areas make up

about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Vanzandt soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective rooting

depth is 20 to 40 inches. Runoff is medium, and the hazard

of water erosion is moderate. Water is perched above the

dense glacial till from December through April.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

western hemlock, red alder, western redcedar, and bigleaf

maple. The common understory plants are Oregongrape,

western swordfern, western brackenfern, vine maple, salal,

red huckleberry, and salmonberry.

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

index for Douglas fir is 175. On the basis of a 50-year site

curve, it is 134. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is 186 cubic

feet per acre per year, occurring at age 60.
The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is harvested,

the slope restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Unsurfaced roads are

soft and slippery when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

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

not readily available. Cut and fill slopes tend to slump when

wet. Following road construction and clearcutting, road

failures and landslides are likely. Soil creep is common on

this unit. Carefully laying out roads and cable

yarding paths, properly timing their use, and using cable

systems that lift logs entirely off the ground reduce the

hazard of erosion.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted

by the dense glacial till, trees are occasionally subject to

windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass VIle.

176-Welcome loam, 5 to 30 percent slopes. This

deep, well drained soil is on mountain shoulder slopes and

ridges. It formed in a mixture of volcanic ash, glacial till,

colluvium, and slope alluvium derived dominantly from

sandstone. The native vegetation is mainly conifers and

shrubs. Elevation is 1,500 to 2,250 feet. The average

annual precipitation is about 60 inches, the average

annual air temperature is about 44 degrees F, and the

average frost-free period is about 125 days.

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

leaves, and twigs 3 inches thick. When mixed to a depth of

6 inches, the surface layer is dark yellowish brown loam.

The subsoil is dark yellowish brown loam 13 inches thick.

The upper 8 inches of the substratum is light olive brown

sandy loam. The lower part is light olive brown fine sandy

loam. Sandstone is at a depth of 50 inches. The depth to

sandstone ranges from 40 to 60 inches. The content of

weathered rock fragments ranges from 35 to 60 percent

throughout this profile. In some areas the surface layer is

sandy loam or silt loam. In other areas the soil has a

gravelly substratum or is more than 60 inches deep over

bedrock.

Included in this unit are small areas of Oakes and

Revel soils, stony areas, poorly drained soils in

depressions, and Welcome soils that have slopes of more

than 30 percent or less than 5 percent. Included areas

make up about 15 percent of the total acreage.

Permeability is moderate in the Welcome soil. Available

water capacity is moderate. The effective rooting depth is

40 to 60 inches. Runoff is slow, and the hazard of water

erosion is slight.

This unit is used as woodland. Douglas fir and western

hemlock are the main woodland species. Among the

trees of limited extent are red alder and western

redcedar. The common understory plants are red

huckleberry, longtube twinflower, western swordfern,

salal, and western brackenfern.

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

index is 135 for Douglas fir and is estimated to be 129 for

western hemlock. On the basis of a 50-year site curve, it is

106 for Douglas fir and is estimated to be 89 for western

hemlock. The highest average growth rate in unmanaged,

even-aged stands of Douglas fir is 139 cubic feet per acre

per year, occurring at age 70. For western hemlock, it is

about 198 cubic feet per acre per year, occurring at age 50.

Areas on ridgetops that are subject to strong, persistent

winds are less productive than the other areas of this unit.

The main limitations affecting timber harvesting are

occasional snowpack and the muddiness caused by

seasonal wetness. The use of wheeled and tracked

equipment when the soil is wet causes excessive rutting.

Using low-pressure ground equipment can minimize

damage to the soil. During an average year, the snowpack

limits the use of equipment and restricts access from

January through March. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use.

Sandstone, a poor-quality rock for road construction, is

readily available. Cut and fill slopes tend to slump when

wet.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling. Steep skid trails and

firebreaks are subject to rilling and gullying unless

adequate water bars are provided or a protective plant

cover is established. A moderate reduction in productivity

can be expected to result from unmanaged fires in

undisturbed areas.

Seedling establishment is the main concern affecting
timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir or western hemlock

seedlings. If seed trees are available, natural reforestation

of cutover areas by western hemlock occurs readily and

reforestation by Douglas fir occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass lVe.

177-Welcome loam, 30 to 60 percent slopes. This

deep, well drained soil is on mountain shoulder slopes and

ridges. It formed in a mixture of volcanic ash, glacial till,

colluvium, and slope alluvium derived dominantly from

sandstone. The native vegetation is mainly conifers and

shrubs. Elevation is 1,500 to 2,250 feet. The average

annual precipitation is about 60 inches, the average annual

air temperature is about 44 degrees F, and the average

frost-free period is about 125 days.

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

leaves, and twigs 4 inches thick. When mixed to a depth of

6 inches, the surface layer is dark yellowish brown loam.

The subsoil is dark yellowish brown loam 17 inches thick.

The upper 12 inches of the substratum is olive brown sandy

loam. The lower part is light olive brown sandy loam.

Sandstone is at a depth of 52 inches. The depth to

sandstone ranges from 40 to 60 inches. The content of

weathered rock fragments ranges from 35 to 60 percent

throughout this profile. In some areas the surface layer is

sandy loam or silt loam. In other areas the soil has a

gravelly substratum or is 40 to 60 inches deep over

bedrock.

Included in this unit are small areas of Oakes and

Revel soils, stony areas, poorly drained soils in

depressions, Rock outcrop, and Welcome soils that have

slopes of more than 60 percent or less than 30 percent.

Included areas make up about 15 percent of the total

acreage.

Permeability is moderate in the Welcome soil. Available

water capacity is moderate. The effective rooting depth is

40 to 60 inches. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Douglas fir and western

hemlock are the main woodland species. Among the trees

of limited extent are red alder and western redcedar. The

common understory plants are red huckleberry, northern

twinflower, western swordfern, salal, and western

brackenfern.

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

index is 135 for Douglas fir and is estimated to be 129 for

western hemlock. On the basis of a 50-year site curve, it is

106 for Douglas fir and is estimated to be 89 for western

hemlock. The highest average growth rate in unmanaged,

even-aged stands of Douglas fir is 139 cubic feet per acre

per year, occurring at age 70. For western hemlock, it is

about 198 cubic feet per acre per year, occurring at age 50.

Areas on ridgetops that are subject to strong, persistent

winds are less productive than the other areas of this unit.

The main limitations affecting timber harvesting are

occasional snowpack, the slope, and the hazard of erosion.

During an average year, the snowpack limits the use of

equipment and restricts access from January through

March. When timber is harvested, the slope restricts the

use of wheeled and tracked skidding equipment. Cable

yarding systems generally are safer and disturb the surface

less extensively. Because most of the roots are

concentrated in the organic mat, loss of this layer during

logging greatly reduces natural fertility and the available

water capacity. Unsurfaced roads are soft when wet and

are subject to deep rutting during rainy periods. Logging

roads require suitable surfacing for year-round use.

Sandstone, a poor-quality rock for road construction, is

readily available. Cut and fill slopes tend to slump when

wet. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and cable yarding paths, properly

timing their use, and using cable systems that lift logs

entirely off the ground can reduce the degree of

compaction, puddling, and erosion. Steep yarding paths,

skid trails, and firebreaks are subject to rilling and gullying

unless adequate water bars are provided or a protective

plant cover is established. A moderate reduction in

productivity can be expected to result from unmanaged

fires in undisturbed areas.

Seedling establishment is the main concern affecting

timber production. The seedling mortality rate is higher on

ridgetops that are subject to strong, persistent winds than

in other areas of this unit. Reforestation can be

accomplished by planting Douglas fir or western hemlock

seedlings. If seed trees are available, natural reforestation

of cutover areas by western hemlock occurs readily and

reforestation by Douglas fir occurs periodically. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

This map unit is in capability subclass VIle.
178-Whatcom silt loam, 0 to 3 percent slopes. This

very deep, moderately well drained soil is in the higher

areas of glaciomarine drift plains. It formed in a mixture of

loess and volcanic ash over glaciomarine drift. The native

vegetation is mainly conifers and shrubs. Elevation is 50 to

600 feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface layer is dark brown silt loam 9

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

brown silt loam. The lower 10 inches is light olive brown,

mottled loam. The upper 9 inches of the substratum is

olive gray, mottled loam. The lower part to a depth of 60

inches is dark gray loam. In some areas the surface layer

is loam or gravelly silt loam. In other areas the substratum

has lenses of sandy material, is 10 to 18 percent clay, is

35 to 45 percent clay, or is 5 to 10 percent cobbles,

stones, or boulders.

Included in this unit are small areas of Skipopa,

Labounty, Bellingham, Birchbay, Laxton, Shalcar, and

Whitehorn soils, somewhat poorly drained soils that are

mottled at a depth of about 12 inches, and Whatcom soils

that have slopes of more than 3 percent. Included areas

make up about 25 percent of the total acreage.

Permeability is moderate in the upper part of the

Whatcom soil and slow in the lower part. Available water

capacity is high. The effective rooting depth is limited by

a seasonal high water table, which is at a depth of 1.5 to

3.0 feet from December through April. Runoff is very

slow, and there is no hazard of erosion.

This unit is used mainly for hay and pasture. It also is

used as woodland and as a site for homes.

Because of the nearly level slope, this soil remains

saturated for longer periods than other Whatcom soils.

This saturation delays the use of equipment, increases the

hazard of puddling, and shortens the effective growing

season unless the soil is drained.

The main limitations in the areas used for hay and

pasture are the seasonal high water table and the slow

permeability. Proper stocking rates, pasture rotation, and

restricted grazing during wet periods help to keep the

pasture in good condition. Grazing when the soil is wet

results in compaction of the surface layer and poor tilth.

The wetness limits the choice of plants and the period of

cutting or grazing and increases the risk of winterkill.

Some areas have been partially drained, which permits

fieldwork to be conducted earlier in the spring and

increases the yields of perennial crops. The wetness can

be reduced in some areas by diversions, which intercept

water, and by open ditches, which remove excess water.

Most crops common to the

survey area can be grown if the drainage system is

adequate.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, bigleaf maple, and paper birch. The

common understory plants are vine maple, red huckleberry,

salal, western swordfern, Oregongrape, western

brackenfern, salmonberry, sweetscented bedstraw, and

trailing blackberry.

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

index for Douglas fir is estimated to be 154. On the basis

of a 50-year site curve, it is estimated to be 116. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 163 cubic feet per acre per

year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the

use of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and are subject to deep rutting during rainy periods.

Logging roads require suitable surfacing for year-round

use. Rock for road construction is not readily available.

Extra rock is needed to maintain a stable, uniform road

surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the seasonal high water table, trees are occasionally

subject to windthrow when the soil is-wet and winds are

strong.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

The main limitations on sites for septic tank absorption

fields are the slow permeability and the high water table.

Installing absorption lines that are longer than normal helps

to overcome these limitations.
This map unit is in capability subclass Ilw.

179-Whatcom silt loam, 3 to 8 percent slopes. This

very deep, moderately well drained soil is in the higher

areas of glaciomarine drift plains. It formed in a mixture of

loess and volcanic ash over glaciomarine drift. The native

vegetation is mainly conifers and shrubs. Elevation is 50 to

600 feet. The average annual precipitation is about 45

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

Typically, the surface layer is dark brown silt loam 9

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

brown silt loam. The lower 10 inches is light olive brown,

mottled loam. The upper 9 inches of the substratum is olive

gray, mottled loam. The lower part to a depth of 60 inches

is dark gray loam. In some areas the surface layer is loam

or gravelly silt loam. In other areas the substratum has

lenses of sandy material, is 10 to 18 percent clay, is 35 to

45 percent clay, or is 5 to 10 percent cobbles, stones, or

boulders.

Included in this unit are small areas of Skipopa,

Labounty, Bellingham, Birchbay, Laxton, Shalcar, and

Whitehorn soils, somewhat poorly drained soils that are

mottled at a depth of 12 inches, and Whatcom soils that

have slopes of more than 8 percent or less than 3 percent.

Included areas make up about 20 percent of the total

acreage.

Permeability is moderate in the upper part of the

Whatcom soil and slow in the lower part. Available water

capacity is high. The effective rooting depth is limited by

a seasonal high water table, which is at a depth of 1.5 to

3.0 feet from December through April. Runoff is slow,

and the hazard of water erosion is slight.

This unit is used mainly for hay and pasture. It also is

used as woodland and as a site for homes.

The main limitations in the areas used for hay and

pasture are the seasonal high water table and the slow

permeability in the substratum. Proper stocking rates,

pasture rotation, and restricted grazing during wet periods

help to keep the pasture in good condition. Grazing when

the soil is wet results in compaction of the surface layer

and poor tilth. The wetness limits the choice of plants and

the period of cutting or grazing and increases the risk of

winterkill. Some areas have been partially drained, which

permits fieldwork to be conducted earlier in the spring and

increases the yields of perennial crops. The wetness can be

reduced in

some areas by diversions, which intercept water, and by

open ditches, which remove excess water.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, bigleaf maple, and paper birch. The

common understory plants are vine maple, red

huckleberry, salal, western swordfern, Oregongrape,

western brackenfern, salmonberry, sweetscented

bedstraw, and trailing blackberry.

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

index for Douglas fir is estimated to be 154. On the basis

of a 50-year site curve, it is estimated to be 116. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 163 cubic feet per acre per

year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the use

of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and are subject to deep rutting during rainy periods.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is not readily available. Extra

rock is needed to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the seasonal high water, table, trees are occasionally

subject to windthrow when the soil is wet and winds are

strong.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

The main limitations on sites for septic tank absorption

fields are the slow permeability and the high water table.

Installing absorption lines that are longer than normal helps

to overcome these limitations.

This map unit is in capability subclass Ile.

180-Whatcom silt loam, 8 to 15 percent slopes. This

very deep, moderately well drained soil is in the higher

areas of glaciomarine drift plains. It formed in a mixture of

loess and volcanic ash over glaciomarine
drift. The native vegetation is mainly conifers and shrubs.

Elevation is 50 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 period is about 170 days.

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

leaves, and twigs 1 inch thick. The surface layer is dark

brown silt loam 5 inches thick. The upper 14 inches of the

subsoil is dark yellowish brown and yellowish brown silt

loam. The lower 15 inches is yellowish brown and olive

brown, mottled loam. The upper 9 inches of the substratum

is light olive brown, mottled loam. The lower part to a

depth of 60 inches is grayish brown, mottled loam. In some

areas the surface layer is loam or gravelly silt loam. In

other areas the substratum has lenses of sandy material, is

10 to 18 percent clay, or is 5 to 10 percent cobbles,

stones, or boulders.

Included in this unit are small areas of Skipopa,

Labounty, Bellingham, Birchbay, Laxton, Squalicum,

Shalcar, and Whitehorn soils and small areas of Whatcom

soils that have slopes of more than 15 percent or less than

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

total acreage.

Permeability is moderate in the upper part of the

Whatcom soil and slow in the lower part. Available water

capacity is high. The effective rooting depth is limited by

a seasonal high water table, which is at a depth of 1.5 to

3.0 feet from December through April. Runoff is

medium, and the hazard of water erosion is moderate.

This unit is used for hay and pasture or as woodland.

The main limitations in the areas used for hay and pasture

are the seasonal high water table, the slope, and the

hazard of erosion during periods of reestablishment. Proper

stocking rates, pasture rotation, and restricted grazing

during wet periods help to keep the pasture in good

condition. Grazing when the soil is wet results in

compaction of the surface layer, poor tilth, and excessive

runoff. The wetness limits the choice of plants and the

period of cutting or grazing and increases the risk of

winterkill. The wetness can be reduced in some areas by

diversions, which intercept water, and by open ditches,

which remove excess water.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, bigleaf maple, and paper birch. The

common understory plants are vine maple, red huckleberry,

salal, western swordfern, Oregongrape, western

brackenfern, salmonberry, sweetscented bedstraw, and

trailing blackberry.

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

index for Douglas fir is estimated to be 154. On the

basis of a 50-year site curve, it is estimated to be 116.

The highest average growth rate in unmanaged, evenaged stands of Douglas fir is about 163 cubic feet per

acre per year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the use

of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft when wet

and are subject to deep rutting during rainy periods.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is not readily available. Extra

rock is needed to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means. Because the rooting depth is restricted by

the seasonal high water table, trees are occasionally

subject' to windthrow when the soil is wet and winds are

strong.

If this` unit is used for homesite development, the main.

limitationis the seasonal high water table. Tile drains and

open drains can be used to lower the water table if a

suitable outlet is available. The wetness can be reduced by

building the house on a pad and by installing drainage tile

around footings if a suitable outlet is available. The main

limitations on sites for septic tank absorption fields are the

seasonal high water table and the slow permeability in the

substratum. These limitations can be overcome by using

interceptor drains, by installing the absorption field at a

shallow depth, and by installing absorption lines that are

longer than normal and that are on the contour. The slope

affects the installation of septic tank absorption fields.

Effluent from absorption fields can surface in downslope

areas: and create a health hazard.

This map unit is in capability subclass IIIe.

181-Whatcom silt loam, 30 to 60 percent slopes.

This very deep, moderately well drained soil is on foothill

back slopes. It formed in a mixture of loess and
volcanic ash over glaciomarine drift. The native vegetation

is mainly conifers and shrubs. Elevation is 50 to 600 feet.

The average annual precipitation is about 45 inches, the

average annual air temperature is about 50 degrees F, and

the average frost-free period is about 170 days.

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

leaves, and twigs 1 inch thick. The surface layer is dark

brown silt loam 5 inches thick. The upper 14 inches of the

subsoil is dark yellowish brown and yellowish brown silt

loam. The lower 15 inches is yellowish brown and olive

brown, mottled loam. The upper 9 inches of the substratum

is light olive brown, mottled loam. The lower part to a depth

of 60 inches is grayish brown, mottled loam. In some areas

the surface layer is loam or gravelly silt loam. In other

areas the substratum has lenses of sandy material, is 10 to

18 percent clay, is 35 to 45 percent clay, or is 5 to 10

percent cobbles, stones, or boulders.

Included in this unit are small areas of Laxton, Sehome,

Squalicum, and Yelm soils, small areas of Bellingham and

Shalcar soils on stream bottoms, and Whatcom soils that

have slopes of less than 30 percent. Included areas make

up about 15 percent of the total acreage.

Permeability is moderate in the upper part of the

Whatcom soil and slow in the lower part. Available water

capacity is high. The effective rooting depth is limited by

a seasonal high water table, which is at a depth of 1.5 to

3.0 feet from December through April. 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. Among the trees of limited extent

are western hemlock, red alder, western redcedar, bigleaf

maple, and paper birch. The common understory plants are

vine maple, red huckleberry, salal, western swordfern,

Oregongrape, western brackenfern, salmonberry,

sweetscented bedstraw, and trailing blackberry.

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

index for Douglas fir is estimated to be 154. On the basis

of a 50-year site curve, it is estimated to be 116. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 163 cubic feet per acre per

year, occurring at age 60.

The main limitations affecting timber harvesting are the

slope and the hazard of erosion. When timber is harvested,

the slope restricts the use of wheeled and tracked skidding

equipment. Cable yarding systems generally are safer and

disturb the surface less extensively. Unsurfaced roads are

soft when wet and are subject to deep rutting during rainy

periods. Logging roads require suitable surfacing for yearround use.

Rock for road construction is not readily available. Extra

rock is needed to maintain a stable, uniform road surface.

Following road construction and clearcutting, road failures

and landslides are likely. Soil creep is common on this unit.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and cable yarding paths, properly timing their use,

and using cable systems that lift logs entirely off the ground

can reduce the degree of compaction, puddling, and

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

subject to rilling and gullying unless adequate water bars

are provided or a protective plant cover is established.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the

seasonal high water table, trees are occasionally subject to

windthrow when the soil is wet and winds are strong.

This map unit is in capability subclass VIIe.

182-Whatcom-Labounty silt loams, 0 to 8 percent

slopes. This map unit is on glaciomarine drift plains that are

hummocky. The Whatcom soil is on 0 to 8 percent slopes,

and the Labounty soil is on 0 to 2 percent slopes. The

native vegetation is mainly trees and shrubs. Elevation is

50 to 600 feet. The average annual precipitation is about

45 inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 170

days.

This unit is 55 percent Whatcom silt loam and 25

percent Labounty silt loam. The components of this unit

occur as areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Skipopa,

Bellingham, and Shalcar soils, somewhat poorly drained

soils that are mottled at a depth of about 12 inches,

Labounty soils that have been artificially drained, and

Whatcom soils that have slopes of more than 8 percent.

Included areas make up about 20 percent of the total

acreage.

The Whatcom soil is very deep and moderately well

drained. It formed in a mixture of loess and volcanic ash

over glaciomarine deposits. Typically, the surface layer is

dark brown silt loam 9 inches thick. The upper 7
inches of the subsoil is dark brown silt loam. The lower 10

inches is light olive brown, mottled loam. The upper 9

inches of the substratum is light olive gray, mottled loam.

The lower part to a depth of 60 inches is dark gray loam. In

some areas the surface layer is loam or gravelly silt loam.

In other areas the substratum has lenses of sandy material,

is 10 to 18 percent clay, is 35 to 45 percent clay, or is 5 to

10 percent cobbles, stones, or boulders.

Permeability is moderate in the upper part of the

Whatcom soil and slow in the lower part. Available water

capacity is high. The effective rooting depth is limited by

a seasonal high water table, which is at a depth of 1.5 to

3.0 feet from December through April. Runoff is slow,

and the hazard of water erosion is slight.

The Labounty soil is very deep and poorly drained. It

formed in glaciomarine drift with an admixture of loess and

volcanic ash. Typically, the surface layer is very dark

grayish brown silt loam 10 inches thick. The upper 6 inches

of the subsoil is grayish brown and light brownish gray,

mottled loam. The lower 19 inches is grayish brown, olive

gray, and light olive gray, mottled loam. The substratum to

a depth of 60 inches is gray loam. In some areas the

surface layer is loam. In other areas the soil has 10 to 18

percent or 35 to 45 percent clay in the subsoil and

substratum, has lenses of sand in the substratum, or has 5

to 15 percent cobbles in the substratum.

Permeability is moderately slow in the Labounty soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at or

near the surface from November through May. Runoff

generally is very slow, but the soil may be ponded during

the winter. There is no hazard of erosion. Runoff from the

higher areas of the microrelief increases the poorly drained

conditions in the depressions.

This unit is used mainly for hay and pasture. It also is

used as woodland and as a site for homes.

The main limitations in the areas used for hay and

pasture are the high water table and the slow

permeability in the substratum of the Whatcom soil.

Proper stocking rates, pasture rotation, and restricted

grazing during wet periods help to keep the pasture in

good condition. Grazing when the soils are wet results in

compaction of the surface layer and poor tilth. The

wetness limits the choice of plants and the period of

cutting or grazing and increases the risk of winterkill.

Tile drains and field ditches are needed to lower the

high water table if deep-rooted plants are to be grown.

Some areas have been partially drained, which permits

fieldwork to be conducted earlier in the spring and

increases the yields of perennial crops. The wetness

can be reduced in some areas by diversions, which

intercept water, and by open ditches, which remove excess

water. The depressions in this unit generally are not

connected and cannot be easily drained.

Douglas fir and red alder are the main woodland

species. Among the trees of limited extent are western

hemlock, western redcedar, bigleaf maple, and paper birch.

The common understory plants are red huckleberry, salal,

western swordfern, Oregongrape, western brackenfern,

salmonberry, Douglas spirea, sweetscented bedstraw,

trailing blackberry, and skunkcabbage.

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

index for Douglas fir on the Whatcom soil is estimated to

be 154. On the basis of a 50-year site curve, it is

estimated to be 116. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is about 163

cubic feet per acre per year, occurring at age 60.

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

index for red alder on the Labounty soil is estimated to be

90. The highest average growth rate in unmanaged, evenaged stands of red alder is about 101 cubic feet per acre

per year, occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the use

of equipment to dry periods. The use of wheeled and

tracked equipment when the soils are wet causes

excessive rutting. Using low-pressure ground equipment

can minimize damage to the soils. Unsurfaced roads are

soft when wet and are subject to deep rutting during rainy

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

available. Extra rock is needed to maintain a stable,

uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate on the

Labounty soil. Reforestation can be accomplished by

planting Douglas fir, western redcedar, or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the high water table, trees are

occasionally
subject to windthrow when the soils are wet and winds are

strong.

If this unit is used for homesite development, the main

limitation is the high water table. Tile drains and open

drains can be used to lower the water table if a suitable

outlet is available. The wetness can be reduced by building

the house on a pad and by installing drainage tile around

footings if a suitable outlet is available. The main limitations

on sites for septic tank absorption fields are the high water

table and the slow permeability in the substratum of the

Whatcom soil. Installing the absorption field in fill approved

by the health district helps to overcome these limitations.

The Whatcom soil is in capability subclass Ile. The

Labounty soil is in capability subclass VIw.

183-Whatcom-Labounty silt loams, 0 to 15 percent

slopes. This map unit is on glaciomarine drift plains that

are hummocky. The Whatcom soil is on 8 to 15 percent

slopes, and the Labounty soil is on 0 to 2 percent slopes.

The native vegetation is mainly trees and shrubs.

Elevation is 50 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 period is about 170 days.

This unit is 55 percent Whatcom silt loam and 25

percent Labounty silt loam. The components of this unit

occur as areas so intricately intermingled that mapping them

separately was not practical at the selected scale of

mapping.

Included in this unit are small areas of Skipopa,

Bellingham, and Shalcar soils, somewhat poorly drained

soils that are mottled at a depth of about 12 inches,

Labounty soils that have been artificially drained, and

Whatcom soils that have slopes of more than 15 percent.

Included areas make up about 20 percent of the total

acreage.

The Whatcom soil is very deep and moderately well

drained. It formed in a mixture of loess and volcanic ash

over glaciomarine deposits. Typically, the surface layer is

dark brown silt loam 9 inches thick. The upper 7 inches of

the subsoil is dark brown silt loam. The lower 10 inches is

light olive brown, mottled loam. The upper 9 inches of the

substratum is olive gray, mottled loam. The lower part to a

depth of 60 inches is dark gray loam. In some areas the

surface layer is loam or gravelly silt loam. In other areas

the substratum has lenses of sandy material, is 10 to 18

percent clay, is 35 to 45 percent clay, or is 5 to 10 percent

cobbles, stones, or boulders.

Permeability is moderate in the upper part of the

Whatcom soil and slow in the lower part. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at a

depth of 1.5 to 3.0 feet from December through April.

Runoff is medium, and the hazard of water erosion is

moderate.

The Labounty soil is very deep and poorly drained. It

formed in glaciomarine drift with an admixture of loess and

volcanic ash. Typically, the surface layer is very dark

grayish brown silt loam 10 inches thick. The upper 6

inches of the subsoil is grayish brown and light brownish

gray, mottled loam. The lower 19 inches is grayish brown,

olive gray, and light olive gray, mottled loam. The

substratum to a depth of 60 inches is gray loam. In some

areas the surface layer is loam. In other areas the soil has

10 to 18 percent or 35 to 45 percent clay in the subsoil and

substratum or has lenses of sand in the substratum.

Permeability is moderately slow in the Labounty soil.

Available water capacity is high. The effective rooting

depth is limited by a seasonal high water table, which is at

or near the surface from November through May. Runoff

generally is very slow, but the soil may be ponded during

the winter. There is no hazard of erosion. Runoff from the

higher areas of the microrelief increases the poorly drained

conditions in the depressions.

This unit is used mainly for hay and pasture. It also is

used as woodland.

The main limitations in the areas used for hay and

pasture are the high water table and the slow

permeability in the substratum of the Whatcom soil.

Proper stocking rates, pasture rotation, and restricted

grazing during wet periods help to keep the pasture in

good condition. Grazing when the soils are wet results in

compaction of the surface layer, poor tilth, and excessive

runoff. The wetness limits the choice of plants and the

period of cutting or grazing and increases the risk of

winterkill.

Tile drains and field ditches are needed to lower the

high water table if deep-rooted plants are, to be grown.

Some areas have been partially drained, which permits

fieldwork to be conducted earlier in the spring and

increases the yields of perennial crops. The wetness can

be reduced in some areas by diversions, which intercept

water, and by open ditches, which remove excess water.

The depressions in this unit generally are not connected

and cannot be easily drained.

Douglas fir and red alder are the main woodland

species. Among the trees of limited extent are western

hemlock, western redcedar, bigleaf maple, and paper

birch. The common understory plants are red huckleberry,

salal, western swordfern, Oregongrape, western

brackenfern, salmonberry, Douglas spirea, sweetscented

bedstraw, trailing blackberry, and skunkcabbage.

On the basis of a 100-year site curve, the mean site
index for Douglas fir on the Whatcom soil is estimated to

be 154. On the basis of a 50-year site curve, it is

estimated to be 116. The highest average growth rate in

unmanaged, even-aged stands of Douglas fir is about 163

cubic feet per acre per year, occurring at age 60.

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

index for red alder on the Labounty soil is estimated to be

90. The highest average growth rate in unmanaged, evenaged stands of red alder is about 101 cubic feet per acre

per year, occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the use

of equipment to dry periods. The use of wheeled and

tracked equipment when the soils are wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soils. Unsurfaced roads are soft when wet

and are subject to deep rutting during rainy periods.

Logging roads require suitable surfacing for year-round use.

Rock for road construction is not readily available. Extra

rock is needed to maintain a stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting timber

production. The high water table hinders root respiration

and thus results in a low seedling survival rate on the

Labounty soil. Reforestation can be accomplished by

planting Douglas fir, western redcedar, or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily. When

openings are made in the canopy, the uncontrolled invasion

and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the high water table, trees are

occasionally subject to windthrow when the soils are wet

and winds are strong.

If this unit is used for homesite development, the main

limitation is the high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

The main limitations on sites for septic tank absorption

fields are the high water table and the slow permeability in

the substratum of the Whatcom soil. These limitations can

be overcome by using interceptor drains, by installing the

absorption field at a shallow depth, and by installing

absorption lines that are longer than normal and that are

on the

contour. The slope affects the installation of septic tank

absorption fields on the Whatcom soil. During the rainy

season, the effluent from onsite sewage disposal systems

can seep at points downslope.

The Whatcom soil is in capability subclass Ille. The

Labounty soil is in capability subclass VIw.

184-Whitehorn silt loam, 0 to 2 percent slopes. This

very deep, poorly drained soil is on wave-reworked

glaciomarine drift plains. It formed in volcanic ash, loess,

glaciofluvial deposits, and glaciomarine drift. The native

vegetation is mainly trees and shrubs. Elevation is 50 to

350 feet. The average annual precipitation is about 35

inches, the average annual air temperature is about 50

degrees F, and the average frost-free period is about 180

days.

Typically, the surface layer is very dark brown silt loam

10 inches thick. The upper 8 inches of the subsoil is dark

brown, light olive brown, and dark grayish brown, mottled

loam and very fine sandy loam. The lower 8 inches is

grayish brown and dark brown,

mottled very gravelly sandy loam. The upper 7 inches of

the substratum is olive brown and grayish brown, mottled

loam. The lower part to a depth of 60 inches is olive brown

and brown, mottled silt loam. The depth to very gravelly

sandy loam ranges from 16 to 24 inches. In some areas the

surface layer is loam. In other areas the soil is sandy

textured in the lower part of the subsoil, has lenses of

sandy material in the substratum, has 10 to 18 percent clay

in the substratum, has 15 to 35 percent pebbles in the

lower part of the substratum, or is 40 to 60 inches deep to

the substratum.

Included in this unit are small areas of Labounty,

Birchbay, Clipper, Bellingham, and Hale soils, small

areas of Shalcar soils in depressions, and drained

Whitehorn soils. Included areas make up about 15

percent of the total acreage.

Permeability is slow in the Whitehorn soil. Available

water capacity is high. The effective rooting depth is

limited by a seasonal high water table, which is at or near

the surface from November through May. Runoff generally

is very slow, but the soil may be ponded during the winter

and spring. There is no hazard of erosion.

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

woodland. The main concerns in the areas used for hay

and pasture: are the high water table and hazards of

compaction and puddling. Proper stocking rates, pasture

rotation, and restricted grazing during wet periods help to

keep the pasture in good condition. Grazing when the soil

is wet results in compaction of the surface layer and poor

tilth. The water table limits the use of this unit to grasses

unless a drainage system is installed. The wetness limits

the choice of plants and
the period of cutting or grazing and increases the risk of

winterkill.

The main limitation in the areas used as cropland is

the high water table. The principal crop is corn silage.

This unit also is suited to other climatically adapted

crops. Some areas have been partially drained, which

permits fieldwork to be conducted earlier in the spring

and increases the yields of perennial crops. The wetness

can be reduced in some areas by diversions, which

intercept water, and by open ditches, which remove

excess water.

Red alder is the main woodland species. Among the

trees of limited extent are western redcedar, western

hemlock, Douglas fir, and black cottonwood. The common

understory plants are salmonberry, western brackenfern,

trailing blackberry, skunkcabbage, sweetscented bedstraw,

red huckleberry, and western swordfern.

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

index for red alder is estimated to be 90. The highest

average growth rate in unmanaged, even-aged stands of

red alder is about 101 cubic feet per acre per year,

occurring at age 40.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the

use of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment can minimize

damage to the soil. Unsurfaced roads are soft 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.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment, seedling mortality, and the

hazard of windthrow are the main concerns affecting

timber production. The high water table hinders root

respiration and thus results in a low seedling survival rate.

Reforestation can be accomplished by planting red alder or

western redcedar seedlings. If seed trees are available,

natural reforestation of cutover areas by red alder occurs

readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the high

water table, trees are frequently subject to windthrow when

the soil is wet and winds are strong.

If this unit is used for homesite development, the main

limitation is the high water table. The wetness can be

reduced by building the house on a pad and by installing

drainage tile around footings if a suitable outlet is available.

The main limitations on sites for septic tank absorption

fields are the slow permeability and the high water table.

Installing the absorption field in fill approved by the health

district helps to overcome these limitations.

This map unit is in capability subclass VIw.

185-Wickersham channery silt loam, 0 to 8 percent

slopes. This very deep, well drained soil is on alluvial fans

and terraces. It formed in alluvium derived dominantly from

phyllite. The native vegetation is mainly conifers and

shrubs. Elevation is 250 to 350 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 49 degrees F, and the average frostfree period is about 170 days.

Typically, the surface layer is very dark gray and dark

gray channery silt loam 12 inches thick. The subsoil is

grayish brown silt loam 9 inches thick. The substratum to

a depth of 60 inches is dark gray extremely channery

loamy sand and very channery loamy sand. Depth to the

extremely channery loamy sand and very channery loamy

sand ranges from 15 to 30 inches. In some areas the

surface layer is silt loam or loam. In other areas the soil

has strata of channery sandy loam or very channery

sandy loam in the substratum, has 35 to 50 percent rock

fragments in the subsoil, or is 30 to 40 inches deep to the

substratum.

Included in this unit are small areas of Wiseman and

Barneston soils, poorly drained alluvial soils, and

Wickersham soils that have slopes of more than 8

percent. Included areas make up about 10 percent of the

total acreage.

Permeability is moderate in the upper part of the

Wickersham soil and very rapid in the lower part.

Available water capacity is moderate. The effective

rooting depth is 60 inches. Runoff is slow, and the

hazard of water erosion is slight. This soil is subject to

rare flooding.

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

as a site for homes. It has few limitations when used for

hay and pasture. Proper stocking rates, pasture rotation,

and restricted grazing during short wet periods help to keep

the pasture in good condition and help to control runoff

and erosion. In summer, irrigation is required for maximum

production.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, paper birch, western

redcedar, western hemlock, and bigleaf maple. The

common understory plants are elderberry, salmonberry,

vine maple, and rose.
On the basis of a 100-year site curve, the mean site

index for Douglas fir is estimated to be 171. On the basis

of a 50-year site curve, it is estimated to be 130. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 182 cubic feet per acre per

year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment when the soil is wet causes

excessive rutting. Using low-pressure ground equipment

can minimize damage to the soil. Unsurfaced roads are soft

and slippery when wet and are subject to deep rutting

during rainy periods. Logging roads require suitable

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

not readily available. Extra rock is needed to maintain a

stable, uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and

using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

The main limitation affecting homesite development is

the hazard of flooding. In shallow excavations special

retainer walls may be needed to keep cutbanks from

caving. The main limitation on sites for septic tank

absorption fields is a poor filtering capacity in the

substratum.

This map unit is in capability subclass Ille.

186-Winston silt loam, 0 to 3 percent slopes. This

very deep, well drained soil is on outwash terraces. It

formed in a mixture of loess and volcanic ash over glacial

outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 300 to 900 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 48 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 3 inches thick. When mixed to a depth of

6 inches, the surface layer is dark brown silt loam. The

upper 5 inches of the subsoil is dark brown loam. The

lower 8 inches is dark yellowish brown gravelly loam. The

upper 6 inches of the substratum is dark yellowish brown

very gravelly loamy sand. The

lower part to a depth of 60 inches is very dark grayish

brown extremely gravelly sand. The depth to extremely

gravelly sand ranges from 14 to 30 inches. In some areas

the surface layer is loam or gravelly silt loam. In other

areas the substratum is very gravelly sandy loam or has 15

to 35 percent rock fragments.

Included in this unit are small areas of Barneston,

Blethen, and Clipper soils; soils that are less than 14

inches deep to extremely gravelly sand; Bellingham and

Shalcar soils in depressions; and Winston soils that have

slopes of more than 3 percent. Included areas make up

about 10 percent of the total acreage.

Permeability is moderate in the upper part of the

Winston soil and very rapid in the lower part. Available

water capacity is moderate. The effective rooting depth is

60 inches. Runoff is very slow, and there is no hazard of

water erosion.

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

as a site for homes. The main limitation in the areas used

for hay and pasture is the moderate available water

capacity. Proper stocking rates, pasture rotation, and

restricted grazing during short wet periods help to keep the

pasture in good condition and help to control runoff and

erosion. In summer, irrigation is required for maximum

production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, and bigleaf maple. The common

understory plants are salal, Oregongrape, western

brackenfern, western swordfern, vine maple, and red

huckleberry.

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

index is 164 for Douglas fir and 162 for western hemlock.

On the basis of a 50-year site curve, it is 125 for Douglas

fir and 114 for western hemlock. The highest average

growth rate in unmanaged, even-aged stands of Douglas

fir is 174 cubic feet per acre per year, occurring at age 60.

For western hemlock, it is 258 cubic feet per acre per

year, occurring at age 50. Severe ice-laden winds from the

northeast cause damage to trees in winter and reduce

yields accordingly.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment during periods when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Logging roads require suitable surfacing for year-round

use. Rounded pebbles for road construction are readily

available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying

out roads and skid trails, properly timing their use, and
using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees

are available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

This unit has few limitations in the areas used for

homesite development. In shallow excavations retainer

walls may be needed to keep cutbanks from caving. If

used -as a base for roads and streets, the soil can be

mixed with the underlying sand and gravel, which can

increase the strength and stability of the soil. The main

limitation on sites for septic tank absorption fields is a

poor filtering capacity in the substratum. Installing the

absorption field in fill approved by the health district helps

to overcome this limitation.

This map unit is in capability subclass Ils.

187-Winston loam, 3 to 15 percent slopes. This very

deep, well drained soil is on outwash terraces. It formed in

a mixture of loess and volcanic ash over glacial outwash.

The native vegetation is mainly conifers and shrubs.

Elevation is 300 to 900 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 48 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 3 inches thick. The surface layer is dark

reddish brown loam 8 inches thick. The subsoil is dark

reddish brown gravelly loam 11 inches thick. The

substratum to a depth of 60 inches is dark yellowish brown

extremely gravelly sand. The depth to extremely gravelly

sand ranges from 14 to 30 inches. In some areas the

surface layer is silt loam or gravelly loam. In other areas

the substratum is very gravelly sandy loam or has 15 to 35

percent rock fragments.

Included in this unit are small areas of Barneston,

Blethen, and Clipper soils; soils that are less than 14

inches deep to extremely gravelly sand; Bellingham and

Shalcar soils in depressions; and Winston soils that have

slopes of more than 15 percent or less than 3 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is moderate in the upper part of the

Winston soil and very rapid in the lower part. Available

water capacity is moderate. The effective rooting depth is

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

is slight.

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

hay and pasture and as a site for homes.

The main limitations in the areas used for hay and

pasture are the hazards of compaction and erosion during

periods of reestablishment and the moderate available

water capacity. Proper stocking rates, pasture rotation, and

restricted grazing during short wet periods help to keep the

pasture in good condition and help to control runoff and

erosion. In summer, irrigation is required for maximum

production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, red alder,

western redcedar, and bigleaf maple. The common

understory plants are salal, Oregongrape, western

brackenfern, western swordfern, vine maple, and red

huckleberry.

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

index is 164 for Douglas fir and 162 for western hemlock.

On the basis of a 50-year site curve, it is 125 for Douglas

fir and 114 for western hemlock. The highest average

growth rate in unmanaged, even-aged stands of Douglas

fir is 174 cubic feet per acre per year, occurring at age 60.

For western hemlock, it is 258 cubic feet per acre per

year, occurring at age 50.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment during periods when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to the soil.

Logging roads require suitable surfacing for year-round

use. Rounded pebbles for road construction are readily

available.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet.

Carefully laying out roads and skid trails, properly timing

their use, and using low-pressure ground equipment can

reduce the degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red

alder occurs readily and reforestation by western hemlock

occurs periodically. When openings are made in the

canopy, the uncontrolled invasion and growth of competing

plants can prevent the establishment of seedlings.

Competing vegetation can be controlled by mechanical or

chemical means.

The main limitation affecting homesite development

is the slope. If used as a base for roads and streets, the

soil can be mixed with the underlying sand and gravel,

which can increase the strength and stability of the soil.

The main limitation on sites for septic tank absorption fields

is a poor filtering capacity in the substratum. The
slope affects the installation of septic tank absorption

fields. The absorption lines should be installed on the

contour.

This map unit is in capability subclass Ille.

188-Winston loam, 15 to 40 percent slopes. This

very deep, well drained soil is on outwash terraces. It

formed in a mixture of loess and volcanic ash over glacial

outwash. The native vegetation is mainly conifers and

shrubs. Elevation is 300 to 900 feet. The average annual

precipitation is about 60 inches, the average annual air

temperature is about 48 degrees F, and the average frostfree period is about 160 days.

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

leaves, and twigs 3 inches thick. The surface layer is dark

reddish brown loam 8 inches thick. The subsoil is dark

reddish brown gravelly loam 11 inches thick. The

substratum to a depth of 60 inches is dark yellowish brown

extremely gravelly sand. The depth to extremely gravelly

sand ranges from 14 to 30 inches. In some areas the

substratum is very gravelly sandy loam or has 15 to 35

percent rock fragments.

Included in this unit are small areas of Barneston,

Blethen, and Clipper soils; soils that are less than 14

inches deep to extremely gravelly sand; Bellingham and

Shalcar soils in depressions; and Winston soils that have

slopes of more than 40 percent or less than 15 percent.

Included areas make up about 10 percent of the total

acreage.

Permeability is moderate in the upper part of the

Winston soil and very rapid in the lower part. Available

water capacity is moderate. The effective rooting depth is

60 inches. Runoff is slow or medium, and the hazard of

water erosion is severe.

This unit is used as woodland. Douglas fir is the main

woodland species. Among the trees of limited extent are

red alder, western hemlock, western redcedar, and bigleaf

maple. The common understory plants are salal,

Oregongrape, western brackenfern, western swordfern, vine

maple, and red huckleberry.

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

index is 164 for Douglas fir and 162 for western hemlock.

On the basis of a 50-year site curve, it is 125 for Douglas

fir and 114 for western hemlock. The highest average

growth rate in unmanaged, even-aged stands of Douglas

fir is 174 cubic feet per acre per year, occurring at age 60.

For western hemlock, it is 258 cubic feet per acre per

year, occurring at age 50.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. The use of

wheeled and tracked equipment during periods when the

soil is wet causes excessive rutting. Using low-pressure

ground equipment can minimize damage to

the soil. Logging roads require suitable surfacing for yearround use. Rounded pebbles for road construction are

readily available. Cut and fill slopes tend to ravel when dry.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a high

degree of puddling when the soil is wet. Carefully laying out

roads and skid trails, properly timing their use, and using

low-pressure ground equipment can reduce the degree of

compaction, puddling, and erosion. Steep skid trails and

firebreaks are subject to rifling and gullying unless

adequate water bars are provided or a protective plant

cover is established.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily and reforestation by western hemlock occurs

periodically. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means.

This map unit is in capability subclass IVe.

189-Wiseman very channery sandy loam, 0 to 8

percent slopes. This very deep, somewhat excessively

drained soil is on alluvial fans. It formed in alluvium

derived dominantly from phyllite. The native vegetation is

mainly conifers and shrubs. Elevation is 250 to 350 feet.

The average annual precipitation is about 60 inches, the

average annual air temperature is about 48 degrees F, and

the average frost-free period is about 170 days.

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

leaves, and twigs 6 inches thick. When mixed to a depth

of 7 inches, the surface layer is dark brown very channery

sandy loam. The upper 13 inches of the substratum is dark

yellowish brown very channery loamy sand. The lower part

to a depth of 60 inches is grayish brown, dark grayish

brown, and dark yellowish brown very channery sand. The

depth to very channery sand or very channery loamy sand

ranges from 2 to 8 inches. In some areas the surface layer

is channery loam or channery sandy loam. In other areas

the soil is very channery sandy loam in the upper part of

the substratum.

Included in this unit are small areas of Wickersham

and Barneston soils and areas of Wiseman soils that

have slopes of more than 8 percent. Included areas

make up about 10 percent of the total acreage.

Permeability is very rapid in the Wiseman soil.

Available water capacity is low. The effective rooting
depth is 60 inches. Runoff is slow, and the hazard of

water erosion is slight. This soil is subject to rare

flooding.

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

as a site for homes. The main limitation in the areas used

for hay and pasture is the low available water capacity.

Proper stocking rates, pasture rotation, and restricted

grazing during short wet periods help to keep the pasture

in good condition and help to control runoff and erosion.

In summer, irrigation is required for maximum production.

Douglas fir is the main woodland species. Among the

trees of limited extent are western hemlock, western

redcedar, red alder, and bigleaf maple. The common

understory plants are western swordfern, western

brackenfern, vine maple, and salmonberry.

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

index for Douglas fir is estimated to be 152. On the basis

of a 50-year site curve, it is estimated to be 115. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 161 cubic feet per acre per

year, occurring at age 60.

The kind of equipment that can be used and the time of

year when it can be used normally are not restricted on this

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

available.

Equipment and logs on the surface result in a

moderate degree of soil displacement when the soil is

dry. Carefully laying out roads and skid trails, properly

timing their use, and using low-pressure ground

equipment can reduce the degree of displacement.

Seedling establishment is the main concern affecting

timber production. A low content of moisture in the surface

layer during the growing season hinders the survival of

planted or naturally established seedlings. Reforestation

can be accomplished by planting Douglas fir or red alder

seedlings. If seed trees are available, natural reforestation

of cutover areas by red alder occurs readily. When

openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can prevent the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means.

The main limitation affecting homesite development is

the hazard of flooding. In shallow excavations special

retainer walls may be needed to keep cutbanks from

caving. The main limitation on sites for septic tank

absorption fields is a poor filtering capacity in the

substratum. Installing the absorption field in fill approved

by the health district helps to overcome this limitation.

This map unit is in capability subclass IVs.

190-Wollard gravelly silt loam, 30 to 60 percent

slopes. This moderately deep, moderately well drained soil

is on mountain back slopes. It formed in a mixture of

volcanic ash, colluvium, and slope alluvium over glacial till

derived dominantly from phyllite. The native vegetation is

mainly conifers and shrubs. Elevation is 2,200 to 3,100 feet.

The average annual precipitation is about 75 inches, the

average annual air temperature is about 42 degrees F, and

the average frost-free period is about 105 days.

Typically, the surface is covered with a mat of needles

and twigs 5 inches thick. When mixed to a depth of 5

inches, the surface layer is yellowish brown gravelly silt

loam. The upper 4 inches of the subsoil is yellowish brown

gravelly silt loam. The lower 21 inches is light brownish

gray gravelly loam. Dense glacial till that crushes to

gravelly loam is at a depth of 30 inches. The depth to

dense glacial till ranges from 20 to 40 inches. The dense

glacial till is similar to a cemented pan. In some areas the

surface layer is gravelly loam or silt loam. In other areas the

soil has 35 to 50 percent rock fragments in the subsoil or

substratum, is 40 to 60 inches deep to dense glacial till,

has more than 6 percent organic carbon in the upper part of

the subsoil, or has rock fragments that are not dominantly

phyllite.

Included in this unit are small areas of Crinker and

Springsteen soils, soils that are less than 20 inches deep

to dense glacial till, Rock outcrop, and Wollard soils that

have slopes of more than 60 percent or less than 30

percent. Included areas make up about 15 percent of the

total acreage. The percentage varies from one area to

another.

Permeability is moderate in the upper part of the

Wollard soil and very slow in the dense glacial till.

Available water capacity is moderate. The effective

rooting depth is 20 to 40 inches. Water is perched

above the dense glacial till from November through

April. Runoff is medium, and the hazard of water

erosion is moderate.

This unit is used as woodland. Western hemlock is the

main woodland species. Among the trees of limited extent

are Pacific silver fir and western redcedar. The common

understory plants are bunchberry dogwood, deer fern,

salmonberry, tall blue huckleberry, and trailing blackberry.

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

index for western hemlock is 139. On the basis of a 50-

year site curve, it is 98. The highest average growth rate in

unmanaged, even-aged stands of western hemlock is 216

cubic feet per acre per year, occurring at age 60. Areas on

ridgetops that are subject to strong, persistent winds are

less productive than the other areas of this unit.
The main limitations affecting timber harvesting are

snowpack, the slope, and the hazard of erosion. During an

average year, the snowpack limits the use of equipment

and restricts access from December through April. When

timber is harvested, the slope restricts the use of wheeled

and tracked skidding equipment. Cable yarding systems

generally are safer and disturb the surface less extensively.

Because most of the roots are concentrated in the organic

mat, loss of this layer during logging greatly reduces

natural fertility and the available water capacity.

Unsurfaced roads are soft and slippery when wet and are

subject to deep rutting during rainy periods. Rock for road

construction is not readily available. Cut and fill slopes tend

to slump when wet. Following road construction and

clearcutting, road failures and landslides are likely. Soil

creep is common on this unit.

Equipment and logs on the surface result in a moderate

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and cable yarding paths, properly timing

their use, and using cable systems that lift logs entirely off

the ground can reduce the degree of compaction and

puddling. Steep yarding paths, skid trails, and firebreaks

are subject to rilling and gullying unless adequate water

bars are provided or a protective plant cover is established.

Seedling mortality, seedling establishment, and the

hazard of windthrow are the main concerns affecting timber

production. A low soil temperature, deep snowpack, and a

short growing season hinder the survival of planted and

natural seedlings and delay their establishment. The

seedling mortality rate is higher on ridgetops that are

subject to strong, persistent winds than in other areas of

this unit. Reforestation can be accomplished by planting

western hemlock or Pacific silver fir seedlings. If seed trees

are available, natural reforestation of cutover areas by

western hemlock and Pacific silver fir occurs periodically.

When openings are made in the canopy, the uncontrolled

invasion and growth of competing plants can delay the

establishment of seedlings. Competing vegetation can be

controlled by mechanical or chemical means. Because the

rooting depth is restricted by the dense glacial till, trees are

occasionally subject to windthrow when the soil is wet and

winds are strong.

This map unit is in capability subclass VIle.

191-Yelm loam, 3 to 8 percent slopes. This very

deep, moderately well drained soil is on terraces. It

formed in a mixture of loess and volcanic ash over

glaciofluvial deposits. The native vegetation is mainly

conifers and shrubs. Elevation is 50 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 period is about 170 days.

Typically, the surface layer is dark brown loam 8 inches

thick. The upper 22 inches of the subsoil is dark brown

and dark yellowish brown loam. The lower 6 inches is dark

yellowish brown and yellowish brown, mottled loam. The

upper 14 inches of the substratum is light brownish gray

and pale brown, mottled very fine sandy loam. The lower

part to a depth of 60 inches is light gray and light olive

brown, mottled very fine sandy loam. In some areas the

surface layer is silt loam or fine sandy loam. In other areas

the soil is 40 to 60 inches deep to sand or clay loam.

Included in this unit are small areas of Laxton, Tromp,

Whatcom, and Whitehorn soils and areas of Yelm soils

that have slopes of more than 8 percent or less than 3

percent. Included areas make up about 15 percent of the

total acreage.

Permeability is moderately rapid in the Yelm soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 1.5 to 3.0 feet from December through March.

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

This unit is used mainly for hay and pasture. It also is

used as woodland and as a site for homes.

The main limitation in the areas used for hay and pasture

is the seasonal high water table. Proper stocking rates,

pasture rotation, and restricted grazing during wet periods

help to keep the pasture in good condition. Grazing when

the soil is wet results in compaction of the surface layer

and poor tilth. Some areas have been partially drained,

mainly by open ditches, but adequate drainage systems

have not been maintained. The wetness can be reduced in

some areas by diversions, which intercept water, and by

open ditches, which remove excess water.

Douglas fir is the main woodland species. Among the

trees of limited extent are red alder, western redcedar, and

bigleaf maple. The common understory plants are salal, red

huckleberry, Oregongrape, western brackenfern, western

swordfern, trailing blackberry, salmonberry, and vine maple.

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

index for Douglas fir is estimated to be 173. On the basis

of a 50-year site curve, it is estimated to be 130. The

highest average growth rate in unmanaged, even-aged

stands of Douglas fir is about 184 cubic feet per acre per

year, occurring at age 60.

The main limitation affecting timber harvesting is the

muddiness caused by seasonal wetness. This limits the use

of equipment to dry periods. The use of wheeled and

tracked equipment when the soil is wet causes excessive

rutting. Using low-pressure ground equipment
can minimize damage to the soil. Unsurfaced roads are

soft when wet and are subject to deep rutting during rainy

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

available. Extra rock is needed to maintain a stable,

uniform road surface.

Equipment and logs on the surface result in a high

degree of compaction when the soil is moist and a

moderate degree of puddling when the soil is wet. Carefully

laying out roads and skid trails, properly timing their use,

and using low-pressure ground equipment can reduce the

degree of compaction and puddling.

Seedling establishment is the main concern affecting

timber production. Reforestation can be accomplished by

planting Douglas fir or red alder seedlings. If seed trees are

available, natural reforestation of cutover areas by red alder

occurs readily. When openings are made in the canopy, the

uncontrolled invasion and growth of competing plants can

prevent the establishment of seedlings. Competing

vegetation can be controlled by mechanical or chemical

means. Because the rooting depth is restricted by the

seasonal high water table, trees are occasionally subject to

windthrow when the soil is wet and winds are strong.

The main limitation affecting homesite development is

the seasonal high water table. The wetness can be reduced

by building the house on a pad and by installing drainage

tile around footings if a suitable outlet is available. The main

limitation on sites for septic tank absorption fields is the

seasonal high water table. This limitation can be overcome

by using interceptor drains, by installing the absorption field

at a shallow depth, and by installing absorption lines that

are longer than normal and that are on the contour.

This map unit is in capability subclasses lIe,

nonirrigated, and Ille, irrigated.

192-Yelm-Urban land complex, 0 to 3 percent slopes.

This map unit is on terraces. The native vegetation is

mainly conifers and shrubs. Elevation is near sea level to

150 feet above sea level. The average annual precipitation

is about 35 inches, the average annual air temperature is

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

about 170 days.

This unit is 50 percent Yelm loam and 30 percent Urban

land. The components of this unit occur as areas so

intricately intermingled that mapping them separately was

not practical at the selected scale of mapping.

Included in this unit are small areas of Laxton, Tromp,

Whatcom, and Whitehorn soils and areas of Yelm soils

that have slopes of more than 3 percent. Included areas

make up about 20 percent of the total acreage.

The Yelm soil is very deep and moderately well

drained. It formed in a mixture of loess and volcanic ash

over glaciofluvial deposits. Typically, the surface layer is

dark brown loam 8 inches thick. The upper 22 inches of the

subsoil is dark brown and dark yellowish brown loam. The

lower 6 inches is dark yellowish brown and yellowish

brown, mottled loam. The upper 14 inches of the

substratum is light brownish gray and pale brown, mottled

very fine sandy loam. The lower part to a depth of 60

inches is light gray and light olive brown, mottled very fine

sandy loam. In some areas the surface layer is silt loam or

fine sandy loam.

Permeability is moderately rapid in the Yelm soil.

Available water capacity is high. The effective rooting depth

is limited by a seasonal high water table, which is at a

depth of 1.5 to 3.0 feet from December through March.

Runoff is very slow, and there is no hazard of erosion.

The Urban land consists of areas covered by streets,

buildings, parking lots, and other structures that so obscure

the soils that identification of the soil series is not feasible.

The Yelm soil is used for lawns, gardens, parks, or

vacant lots.

If this unit is used for homesite development, the main

limitation is the seasonal high water table. The wetness

can be reduced by building the house on a pad and by

installing drainage tile around footings if a suitable outlet is

available. The main limitation on sites for septic tank

absorption fields is the seasonal high water table. This

limitation can be overcome by using interceptor drains, by

installing the absorption field at a shallow depth, and by

installing absorption lines that are longer than normal and

that are on the contour.

The Yelm soil is in capability subclass IIw. The Urban

land is in capability subclass VIIIs.

Prime Farmland

Prime farmland is one of several kinds of important

farmland defined by the U.S. Department of Agriculture. It

is of major importance in meeting the Nation's short- and

long-range needs for food and fiber. Because the supply of

high-quality farmland is limited, the U.S. Department of

Agriculture recognizes that responsible levels of

government, as well as individuals, should encourage and

facilitate the wise use of our Nation's prime farmland.

Prime farmland, as defined by the U.S. Department of

Agriculture, is the land that is best suited to food, feed,

forage, fiber, and oilseed crops. It may be cultivated land,

pasture, woodland, or other land, but it is not urban or

built-up land or water areas. It either is used for food or

fiber crops or is available for those
crops. The soil qualities, growing season, and moisture

supply are those needed for a well managed soil to

produce a sustained high yield of crops in an economic

manner. Prime farmland produces the highest yields with

minimal expenditure of energy and economic resources,

and farming it results in the least damage to the

environment.

Prime farmland has an adequate and dependable supply

of moisture from precipitation or irrigation. The temperature

and growing season are favorable. The level of acidity or

alkalinity is acceptable. Prime farmland has few or no

rocks and is permeable to water and air. It is not

excessively erodible or saturated with water for long

periods and is not frequently flooded during the growing

season. The slope ranges mainly from 0 to 8 percent. More

detailed information about the criteria for prime farmland is

available at the local office of the Soil Conservation

Service.

About 67,000 acres, or 13 percent of the survey area, all

in the western part, meets the requirements for prime

farmland without drainage measures, flood control, or

irrigation. In addition, 65,000 acres, or nearly 13 percent,

mostly in general soil map units 5, 6, 7, and 8, meets the

requirements for prime farmland where the soils are

drained; 17,000 acres, or 3 percent, all in general soil map

unit 1, is prime farmland where the soils are protected

from flooding or are not frequently flooded; 15,000 acres,

or nearly 3 percent, mostly in

general soil map units 4 and 5, is prime farmland where

the soils are irrigated; and 18,000 acres, or about 4

percent, all in general map unit 3, is prime farmland where

the soils are drained and protected from flooding.

A recent trend in land use in some parts of the survey

area has been the loss of some prime farmland to

industrial and urban uses. The loss of prime farmland to

other uses puts pressure on marginal lands, which

generally are more erodible, droughty, and less productive

and cannot be easily cultivated.

The map units in the survey area that are considered

prime farmland are listed in table 5. This list does not

constitute a recommendation for a particular land use. The

extent of each listed map unit is shown in table 4. The

location is shown on the detailed soil maps at the back of

this publication. The soil qualities that affect use and

management are described under the heading "Detailed

Soil Map Units."

Soils that have limitations, such as a seasonal high

water table, frequent flooding during the growing season,

or inadequate rainfall, qualify for prime farmland only in

areas where these limitations have been overcome by such

measures as drainage, flood control, or irrigation. The need

for these measures is indicated after the map unit name in

table 5. Onsite evaluation is needed to determine whether

or not these limitations have been overcome by corrective

measures.
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

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 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 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

Prepared by John A. Gillies, district conservationist, Soil

Conservation Service.

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.

Approximately 288,000 acres in the survey area is in

capability classes II, III, and IV. About 81,000 acres in

Whatcom County is used as cropland and about 23,500

acres as pasture. The primary cash crops are red

raspberries, potatoes, sweet peas, carrots, and small grain.

The primary forage crops are corn and grass silage. The

county leads the state in the production of dairy products,

red raspberries, and seed potatoes. There are about 500

dairy producers and 1,445 full- and part-time farmers in the

county. The farms operated by full-time farmers average

about 120 acres in size, and the ones operated by parttime farmers average about 45 acres.

The drainage class and fertility level of the soils in the

survey area vary widely. About 38,585 acres on the broad

flood plains along the Nooksack River is intensively used

for agricultural purposes. On 62,685 acres the soils

formed in glacial outwash, and on about 12,955 acres the

soils used for agricultural purposes formed in organic

material.

The well drained and moderately well drained soils on

terraces and flood plains are well suited to most of the

crops grown in the area. These include the Lynden,

Kickerville, Laxton, and Tromp soils on glacial terraces

and the Mt. Vernon and Puyallup soils on flood plains.

Approximately 30,000 acres of the well drained soils is

irrigated.

About 60 percent of the acreage used for crops and

pasture in Whatcom County requires drainage of excess

surface and subsurface water. Locating adequate outlets for

drainage systems is difficult on the Bellingham and

Labounty soils, which are in
depressions. These soils are used mainly for hay and late

pasture unless they are drained. A combined surface and

subsurface drainage system is used on poorly drained and

very poorly drained soils to maximize the production of

crops and forage. Drainage systems need to be maintained

on Briscot, Oridia, Sumas, and Puget soils on flood plains

and on Hale, Clipper, and Everson soils on glacial outwash

terraces. The specific design of the drainage systems

varies with the soil type and crop to be grown.

Most of the tillable soils in the survey area respond well

to applications of fertilizer and lime. Most of the soils are

medium acid or slightly acid and require lime to raise the

pH value and increase the percent of base saturation. On

all soils the amount of lime and fertilizer required should be

based on a soil test, the needs of the crop, and the

expected yield. Animal manure and sewage sludge can

provide a significant portion of a crop's fertilizer needs.

Application rates and timing vary with the type of soil, the

needs of the crop, and the method of storage and

distribution. The Soil Conservation Service can provide

assistance in determining proper waste utilization on a

specific soil and for a specific crop. The latest information

and suggestions for growing crops can be obtained from

the local office of the Cooperative Extension Service or the

Soil Conservation Service.

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 6. 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 land

capability classification of each map unit also is shown in

the table.

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,

animal manure, and green manure crops; and harvesting

that ensures 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.

Many of the soils in the survey area have adjacent

layers with abrupt differences in texture and pore size. The

pore size discontinuity influences the water-holding

capacity of the soil. A soil underlain by sand, such as

Lynden sandy loam, retains more water than a similar soil

that has a uniform sandy loam profile. This increased

water-holding capacity results from the inability of the sand

to conduct water until the upper sandy loam layer has a

sufficient water content to produce free water. The field

capacity of the sandy loam will be about 10 percent higher

than that derived from pressure membrane analysis.

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 6 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 for those crops.

Land Capability Classification

Land capability classification shows, in a general way,

the suitability of soils for most kinds of field crops (42).

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 criteria used in

grouping the soils do not include major and generally

expensive landforming that would change slope, depth, or

other characteristics of the soils, nor do they include

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

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.

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 few 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 hazard is the 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, 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, woodland,

wildlife habitat, or recreation.

The acreage of soils in each capability class and

subclass is shown in table 7. The capability

classification of each map unit is given in the section

"Detailed Soil Map Units" and in the yields table.

Woodland Management and Productivity

This section was prepared by Dennis J. Robinson, area forester, Soil

Conservation Service; Sanderson Page, soil scientist, Soil Conservation

Service; and Robert Freimark, forester, Washington State Department of

Natural Resources.

Soils vary in their ability to produce and sustain

woodland. The thickness of the soil, fertility, texture, and

available water capacity, along with other factors,

influence tree growth.

A majority of the soils in the survey area have the

potential to produce wood crops. Most of the alluvial

soils have been converted from woodland to cropland used

for the production of feed, forage, and truck crops. In their

natural state, these soils supported coniferous and

hardwood stands in varying degrees of mixture and density.

Poorly drained and flood-influenced soils adjacent to bodies

of water and major river and stream courses have the

potential to support stands of red alder or black cottonwood

interspersed with bigleaf maple and northwestern paper

birch.

Elevation and aspect play a major role in determining

the composition of species in a stand. In general, at

elevations ranging from sea level to 3,000 feet above sea

level, stands of Douglas fir and western hemlock are mixed

to varying degrees. On south-facing slopes in the same

elevation range, however, pure stands of Douglas fir occur

(15). Western hemlock grows in pure stands at elevations

of 1,600 to 2,000 feet and on north-facing slopes at lower

elevations. At elevations above 3,000 feet, Pacific silver fir,

western hemlock, mountain hemlock, and Alaska cedar are

mixed to varying degrees. Pacific silver fir and some

western hemlock also grow in narrow areas where cool air

drains at elevations of 2,000 to 3,000 feet.

Red alder is the main deciduous tree in the survey area.

Northwestern paper birch is a significant component of the

hardwood stands. Red alder grows in pure stands and in

mixed stands of deciduous and conifer species. It

commonly invades clear-cut areas and becomes dominant

unless intensive management practices are applied. A

barren mineral soil, an adequate seed source, and an

abundant supply of moisture are needed for the

establishment of red alder (15).

In areas of soils that are influenced by serpentine,

overstory vegetation is characterized by stunted, growthinhibited stands of western hemlock, western redcedar, and

Alaska cedar (20). Regeneration of harvested species is

difficult on these soils. Planting stock should be obtained

from suitable seed trees in the area.

Reforestation is the main concern affecting the

production of timber on most of the soils in the survey

area. Hand planting of adapted conifer seedlings is carried

out in most areas. The presence of red alder and brush

species is a significant deterrent to successful reforestation

of conifers at elevations below 1,000 feet.

The main limitations affecting timber harvesting are the

muddiness caused by seasonal wetness and the slope. A

variety of equipment is used. Operating ground equipment

on slopes that are steeper than 30 percent is considered

hazardous. Cable systems that lift logs entirely off the

ground are safer and less damaging to the soil. Using lowpressure ground equipment can
reduce the degree of soil compaction and displacement. In

areas where the soils have a high content of phyllite,

greater care is needed in the design and construction of

roads and in the selection of harvesting equipment.

Many of the wood products produced in the survey area

are transported to processing facilities outside of the area.

Much of the wood for pulp is used locally at a large pulp

and paper mill. Other processors in the area include a few

shake and shingle mills, one plywood and veneer mill, four

softwood lumber mills, and one outlet for posts, poles, and

pilings. Red alder wood products are generally transported

out of the survey area for processing.

A demand for urban and industrial development sites

exists in the survey area. Total commercial woodland

acreage may decline in the area as pressure to convert to

other uses increases, but loss of productive acres may be

partially offset by intensive management practices.

A statistical analysis was used in obtaining the woodland

site data in this survey. Data from forest tree sites were

taken by a forester. When a prospective tree stand on a

particular map unit was identified by the forester, five site

trees, generally the dominant trees on the site, were

selected. Tree height, diameter at breast height, and breastheight age were determined. All ground vegetation also was

identified and recorded on a data card (39).

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

index for the five trees was calculated by adjusting the

breast-height age to total age for Douglas fir (28) and

western hemlock (4). On the basis of a 50-year site curve,

the mean site index was calculated directly from average

breast-height age and total tree height for Douglas fir (22)

and western hemlock (47). The site index for red alder was

calculated in the same manner using average age at

breast-height and total height (49). A statistical analysis of

all site indices for each soil series or map unit was

conducted. Standard deviation, standard error of the mean,

and coefficient of variation were calculated (38).

All of the site data for a particular series was analyzed

initially to obtain a coefficient of variation of less than 8

percent. If the 8 percent threshold was exceeded, then the

site data applicable to each map unit within the series was

analyzed in the same manner. If a 5 foot or more difference

in site indices existed between map units, then those

calculated site indices were used. If the difference was less

than 5 feet and the coefficient of variation was less than 8

percent, the site indices were averaged for the series. For

series without adequate site data, an estimated site index

was established using data gathered for similar soils (45).

Soil surveys are becoming increasingly more

important to forest managers as they seek ways of

increasing the productivity of their forested lands. Plants

respond better to applications of fertilizers on some soils

than on others. Some soils are more susceptible to

landslides and erosion after road building and harvesting,

and others require special effort to harvest and reforest.

Each description of the map units suitable for producing

wood crops includes information about forest productivity,

timber production, limitations affecting timber harvesting,

and common forest understory plants. The methods and

procedures used to develop the information for the map

units are described in the National Forestry Manual (45) and

the Forest Land Grading Procedures Handbook (39).

Table 8 summarizes forestry information given in the map

unit descriptions and can serve as a quick reference for

important forestry interpretations. Map unit symbols are

listed, and the ordination (woodland suitability) symbol for

each map unit in the table is given. All soils having the

same ordination symbol require the same general kinds of

forest management and have about the same potential

productivity.

The ordination symbol is based on a uniform system that

indicates the potential productivity of an individual soil and

the principal hazards or limitations of that soil. The first

element of the ordination symbol is a number that denotes

the potential productivity in terms of cubic meters of wood

per hectare per year for the indicator tree species. The

potential productivity is based on the site index and the

corresponding culmination of the mean annual increment.

For example, the number 1 indicates a potential

production of 1 cubic meter of wood per hectare (14.3

cubic feet per acre) per year and 10 indicates a potential

production of 10 cubic meters of wood per hectare (143

cubic feet per acre) per year.

The second element of the symbol, a letter, indicates the

major kind of soil characteristic that limits tree growth or

management. The letter X indicates stoniness or rockiness;

W, excessive water, either seasonally or year round, in or

on the soil; T toxic substances within the root zone; D,

restricted rooting depth; C, clayey soils; S, sandy soils; F,

fragmented or skeletal soils with coarse fragments that are

more than 2 millimeters and less than 10 inches in size;

and R, relief or slope. The letter A indicates no or only

slight limitations affect use and management. If a soil has

more than one limitation, the letter denoting the most

limiting characteristic is used.

The number designation of the ordination symbol also

represents the productivity class. Productivity class is

calculated for other important common trees on the soil for

which a site index has been provided. This
figure denotes potential productivity in terms of cubic

meters of wood per hectare per year.

In table 8 the soils also are rated for a number of

factors to be considered in management. Ratings of

slight, moderate, and severe are used to indicate the

degree of major soil limitations. For each moderate or

severe rating, a sentence in the applicable map unit

description explains the soil factor or factors that are the

basis of that rating.

Ratings of erosion hazard indicate the probability that

damage will occur as a result` of site preparation and

cutting where the soil is exposed along roads, skid trails,

fire lanes, and log-handling areas. Forests that have been

burned or overgrazed are also subject to erosion. Ratings

of the erosion hazard are based on the percent of the

slope. A rating of slight indicates that no particular

prevention measures are needed under ordinary

conditions. A rating of moderate indicates that erosioncontrol measures are needed in certain silvicultural

activities. A rating of severe indicates that special

precautions are needed to control erosion in most

silvicultural activities.

Ratings of the equipment limitation reflect the soil

characteristics and conditions that restrict the use of

equipment, either year round or seasonally. A rating of

slight indicates that the use of equipment is not normally

restricted 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 or management, or a hazard in the

use of equipment. Slope and wetness are the main factors

that cause equipment limitations. As slope gradient and

length increase, using wheeled equipment becomes more

difficult. On the steeper slopes, tracked equipment must be

used. On the steepest slopes, even tracked equipment

cannot be operated safely and more sophisticated systems

must be used. Wetness, especially in combination with fine

texture, can severely limit the use of equipment, making

harvesting practical only during dry summer months.

Ratings of seedling mortality indicate the probability of the

death of naturally occurring or planted tree seedlings as

influenced by kinds of soil or topographic conditions. Plant

competition is not considered in the ratings. The ratings

apply to healthy, dormant seedlings from good stock that

are properly planted or naturally established seedlings that

germinate during a period of insufficient soil moisture. A

rating of slight indicates that no significant mortality is

expected under usual conditions; moderate indicates that

some mortality can be expected and that extra precautions

are advisable; and severe indicates that mortality will be

high and

extra precautions are essential for successful

reforestation. Seedling mortality can be caused by

wetness; by droughtiness in the surface layer, especially

on south- or southwest-facing slopes; or by the position of

the soil on a ridgetop. To offset these, larger than usual

planting stock, special site preparation, a surface

drainage system, or reinforcement planting may be

needed.

Ratings of windthrow hazard are based on soil

characteristics that affect the development of tree roots and

the ability of the soil to hold trees firmly. A rating of slight

indicates that trees normally are not blown down by the

wind. Strong winds may break the trees but do not uproot

them. A rating of moderate indicates that an occasional tree

may be blown down during periods of excessive wetness

and moderate or strong winds, and a rating of severe

indicates that many trees are expected to be blown down

during these periods. A restricted rooting depth caused by

a high water table, underlying bedrock, and an impervious

layer or poor anchoring of roots because of a loose surface

layer and subsoil are responsible for windthrow. Moderate

and severe ratings indicate the need for more care in

thinning the edges of woodland stands, a plan calling for

periodic removal of windthrow trees, and an adequate road

and trail system to allow for this removal.

Ratings of plant competition indicate the likelihood of the

invasion or growth of undesirable brushy plants when

openings are made in the tree canopy. A rating of slight

indicates that unwanted brushy plants are not likely to

delay natural reforestation and that planted seedlings can

survive and grow well without undue competition; moderate

indicates that competition will delay natural or planted

reforestation; and severe indicates that competition can be

expected to prevent natural or planted reforestation.

Favorable climate and soil characteristics account for plant

competition. In many areas the key to predicting brush

competition is the quantity and proximity of seed sources of

undesirable plants or the quantity of unwanted bush

rootstocks that will resprout after harvest activities.

Moderate and severe ratings indicate the need for careful

and thorough cleanup after harvest in preparation for

reforestation and the possible need for mechanical or

chemical treatment to retard the growth of brush and allow

seedlings to become established.

The potential productivity of common trees on a soil is

expressed as a site index and a productivity class. The site

index is determined by measuring the height and age of

selected trees within stands of a given species (4, 22, 28,

47, 49). It applies to fully stocked, even-aged, unmanaged

stands. The greatest timber yields, usually expressed in

board feet or cubic feet per
acre, can be expected from map units with the highest site

index values. These values can be converted into

estimated yields at various ages by carefully using

appropriate yield publications (4, 9, 10, 28, 48, 49).

Common trees are listed in the same order as that of

their general occurrence observed on the map unit.

Generally, only one or two species will predominate.

Trees to plant are those that are planted for reforestation

or that, under suitable conditions, are allowed to regenerate

naturally. The species listed in table 8 are suited to the

soils and can be used for commercial wood production. The

desired product, the topographic position (such as a

ridgetop), and personal preference are three of many

factors that can influence the choice of suitable trees to

use for reforestation.

Windbreaks and Environmental Plantings

Dennis J. Robinson, area forester, Soil Conservation Service,

helped to prepare this section.

Windbreaks protect livestock, buildings, and yards from

wind and snow. They also protect fruit trees and gardens,

and they furnish habitat for wildlife. Several rows of lowand high-growing broadleaf and coniferous trees and

shrubs provide the most protection.

Most of the lowland soils in the survey area were

originally forested. A large portion of the native vegetation,

however, has been cleared for farms and towns. In the

north-central and northeast parts of the lowland area,

between the towns of Everson and Sumas, windbreaks

protect farm buildings and houses from northeast winds.

Weather systems moving southwest from the Fraser River

Valley of Canada bring snow and cold, desiccating winds

to the area. As a result, windbreaks are needed for

protection. Windbreaks and environmental plantings can be

established. Measures that maintain them are needed.

Plantings can include a single species or a variety of

species.

The most effective arrangement of windbreak plantings

consists of dense, low-growing shrubs in the windward

rows, taller deciduous trees or shrubs in the center row or

rows, and evergreen trees or shrubs on the leeward side

(44). Such an arrangement makes the windbreak more

effective in winter. If only one or two rows are planted,

species that provide maximum protection should be

selected. For example, if protection of a large area is

needed, tall trees should be planted, or if control of ground

winds is needed, dense shrubs or evergreens are most

effective. Generally, wind movement on the leeward side

of the planting is effectively reduced to a distance equal to

10 to 20 times the height of the windbreak.

Plants suitable for windbreaks and environmental

plantings in the survey area have not been tested. Many

windbreaks that are installed consist primarily of adapted

native species of deciduous trees and shrubs and

coniferous trees. Lombardy poplar is the most suitable

deciduous tree. Douglas fir, Rocky Mountain juniper,

western redcedar, ponderosa pine, and grand fir are the

most commonly used evergreen species. Native and

adapted shrub species, such as willows and common lilac,

are suitable for use in the low-growing shrub row in the

windbreak plantings. Generally, adequate moisture for

growth is provided by normal precipitation. Irrigation may

be necessary, however, on the drier sites in late August and

September.

The spacing between rows and between the trees and

shrubs in the rows is important. Deciduous trees should be

spaced at least 12 feet apart in the row, shrubs should be 3

or 4 feet apart, and evergreen trees should be at least 6

feet apart. The rows of trees should be 12 to 18 feet apart.

The size of the cultivating equipment is a consideration in

row-to-row spacing.

Other aspects of layout are equally important.

Farmstead windbreaks should be at least 100 feet from

the buildings so that air can move on hot days. Rounded

corners are easier to cultivate than square ones. Areas to

be planted should be free of vegetation before the trees or

shrubs are planted.

Environmental plantings help to beautify and screen

houses and other buildings and to abate noise. The

plants, mostly evergreen shrubs and trees, are closely

spaced. To ensure plant survival, a healthy planting stock

of suitable species should be planted properly on a well

prepared site and maintained in good condition.

Additional information on planning windbreaks and

screens and planting and caring for trees and shrubs

can be obtained from local offices of the Soil

Conservation Service or the Cooperative Extension

Service or from a local nursery.

Recreation

Whatcom County has many areas of scenic,

recreational, geologic, and historic interest. These areas

are used for camping, hiking, hunting, fishing, sightseeing,

mountain climbing, bicycling, picnicking, and boating.

Public areas available for recreation within the survey area

include eight county parks, three state parks, a state game

range, and several fish hatcheries.

Important marine features include Lummi and Eliza

Islands, Point Francis, Bellingham Bay, numerous beaches,

and scenic Chuckanut Drive, which follows the water's

edge south of Bellingham. The western boundary of Mount

Baker National Forest is the eastern boundary of the

survey area. Lake Whatcom, Lake Samish, the Nooksack

River, and the Strait of Georgia
are prime fishing areas. Mount Baker and Twin Sisters

Mountain, immediately east of the survey area, are

important recreational areas.

The soils of the survey area are rated in table 9

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 sewer lines. 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 9, 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 9 can be supplemented by

other information in this survey, for example,

interpretations for septic tank absorption fields in table 12

and interpretations for dwellings without basements and

for local roads and streets in table 11.

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 and horseback riding 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

The survey area contains a wide variety of habitat types

ranging from salt water to alpine mountain peaks, which

support a variety of wildlife. Approximately three-fourths of

the survey area on the western slope of the Cascade

Range is covered by coniferous forests. Numerous rocky

peaks, which are above 8,000 feet, provide a home for

species characteristic of these alpine environments. These

species include pika, white-tailed ptarmigan, and mountain

goat.

The western one-fourth of the survey area consists of

lowlands and relatively flat terrain, which is used mainly for

agriculture. Agricultural land is interspersed with numerous

remnant patches of coniferous forest and riparian

woodland. These small wooded areas support woodland

wildlife and provide cover for openland wildlife. The

lowlands contain numerous wetlands, sloughs, and creeks,

which provide important habitat for fish, waterfowl, and

other aquatic and wetland wildlife.

Much of the survey area is drained by the Nooksack

River, which flows into Bellingham Bay. About 650 rivers

and streams are in the Nooksack drainage system, which

includes about 1,300 miles of streams and tributaries. Bald

eagles concentrate along the river in winter to feed on the

salmon, steelhead, and cutthroat trout that migrate

upstream each year. In an average year, about 55,000

adult salmon return to spawn in the Nooksack drainage

system.

Bellingham, Lummi, Chuckanut, and Birch Bays

provide habitat for saltwater fish and shellfish. An
abundance of marine invertebrates and aquatic

vegetation attract large resident and wintering

populations of loons, grebes, cormorants, herons,

ducks, shorebirds, gulls, ferns, and black brants.

Soils and climate 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 10, 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, trillium,

bedstraw, and fireweed.

Hardwood trees and woody understory produce nuts or

other fruit, buds, catkins, twigs, bark, and foliage. Soil

properties and features that affect the growth of hardwood

trees and shrubs are depth of the root zone, available

water capacity, and wetness. Examples of these plants

are red alder, bigleaf maple, Pacific dogwood,

cottonwood, vine maple, and willow. Examples of fruitproducing trees and shrubs that are suitable for planting

on soils rated good are blackberry, apple, cherry,

crabapple, and mountain ash.

Coniferous plants furnish browse and seeds. 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 Douglas fir, western hemlock, noble

fir, and western redcedar.

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,

Oregongrape, and salmonberry.

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. Wildlife attracted to these areas

include California quail, pheasant, mourning dove,

meadowlark, chipping sparrow, and brush rabbit.

Habitat for woodland wildlife consists of areas of

deciduous and coniferous plants and associated grasses,

legumes, and wild herbaceous plants. Wildlife attracted to

these areas include blue and ruffed grouse, thrushes,

woodpeckers, squirrels, Cascade red fox, mountain goat,

ptarmigan, black-tailed 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, herons, 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 or 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 evaluate the potential of

areas for residential, commercial, industrial, and recreation

uses; make preliminary estimates of construction

conditions; evaluate alternative routes for roads, streets,

highways, pipelines, and underground cables; evaluate

alternative sites for sanitary landfills, septic tank absorption

fields, and sewage lagoons; plan detailed onsite

investigations of soils and geology; locate potential sources

of gravel, sand, earthfill, and topsoil; plan drainage

systems, irrigation systems, ponds, terraces, and other

structures for soil and water conservation; and 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 11 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 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, slope, and

flooding affect the ease of excavation and construction.

Landscaping and grading that require cuts and fills of more

than 5 or 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), shrink-swell potential, frost action

potential, and depth to a high water table affect the trafficsupporting 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 12 shows the degree and 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 12 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 filter the effluent effectively. 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 12 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 groundwater pollution. Ease of excavation and revegetation

needs to be considered.

The ratings in table 12 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 wind erosion.

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 13 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 to 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, a 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 a 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 depth to the water table is

less than 1 foot. These soils 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 13, 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 14 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

and for embankments, dikes, and levees. 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, terraces and

diversions, and grassed waterways.

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.

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 control 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.

Grassed waterways are natural or constructed channels,

generally broad and shallow, that conduct surface water to

outlets at a nonerosive velocity. Large stones, wetness,

slope, and depth to bedrock or to a cemented pan affect

the construction of grassed waterways. A hazard of wind

erosion, low available water capacity, restricted rooting

depth, toxic substances such as salts or sodium, and

restricted permeability adversely affect the growth and

maintenance of the grass after construction.
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 classification, 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 15 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 the content of particles coarser than sand

is as much as 15 percent, 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). Both systems are described in

the PCA Soil Primer (33).

The Unified system classifies soils according to

properties that affect their use as construction material.

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, CL-ML.

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 grainsize 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 A8 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 ovendry 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 generally 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 16 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 earthmoving operations.

Moist bulk density is the weight of soil (ovendry) per unit

volume. Volume is measured when the soil is at field

moisture capacity, that is, the moisture content at 1/3 bar

moisture tension. Weight is determined after drying the soil

at 105 degrees C. In this table, the estimated moist bulk

density of each major soil horizon is expressed in grams

per cubic centimeter of soil material that is less than 2

millimeters in diameter. Bulk density data are used to

compute shrink-swell potential, available water capacity,

total pore space, and other soil properties. The moist bulk

density of a soil indicates the pore space available for

water and roots. A bulk density of more than 1.6 can

restrict water storage and root penetration. Moist bulk

density is influenced by texture, kind of clay, content of

organic matter, and soil structure.

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.

Salinity is a measure of soluble salts in the soil at

saturation. It is expressed as the electrical conductivity of

the saturation extract, in millimhos per centimeter at 25

degrees C. Estimates are based on field and laboratory

measurements at representative sites of nonirrigated soils.

The salinity of irrigated soils is affected by the quality of the

irrigation water and by the frequency of water application.

Hence, the salinity of soils in individual fields can differ

greatly from the value given in the table. Salinity affects the

suitability of a soil for crop production, the stability of soil if

used as construction material, and the potential of the soil

to corrode metal and concrete.

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.

Wind erodibility groups are made up of soils that have

similar properties affecting their resistance to wind erosion

in cultivated areas. The groups indicate the susceptibility of

soil to wind erosion. Soils are grouped according to the

following distinctions:

1. Coarse sands, sands, fine sands, and very fine

sands. These soils are generally not suitable for crops.

They are extremely erodible, and vegetation is difficult to

establish.

2. Loamy coarse sands, loamy sands, loamy fine sands,

loamy very fine sands, and sapric soil material. These soils

are very highly erodible. Crops can be grown if intensive

measures to control wind erosion are used.

3. Coarse sandy loams, sandy loams, fine sandy

loams, and very fine sandy loams. These soils are highly

erodible. Crops can be grown if intensive measures to

control wind erosion are used.

4L. Calcareous loams, silt loams, clay loams, and silty

clay loams. These soils are erodible. Crops can be grown if

intensive measures to control wind erosion are used.

4. Clays, silty clays, noncalcareous clay loams, and silty

clay loams that are more than 35 percent clay. These soils

are moderately erodible. Crops can be grown if measures to

control wind erosion are used.

5. Noncalcareous loams and silt loams that are less

than 20 percent clay and sandy clay loams, sandy clays,

and hemic soil material. These soils are slightly erodible.

Crops can be grown if measures to control wind erosion are

used.

6. Noncalcareous loams and silt loams that are

more than 20 percent clay and noncalcareous clay

loams that are less than 35 percent clay. These soils are

very slightly erodible. Crops can be grown if ordinary

measures to control wind erosion are used.

7. Silts, noncalcareous silty clay loams that are less than

35 percent clay, and fibric soil material. These soils are

very slightly erodible. Crops can be grown if ordinary

measures to control wind erosion are used.

8. Soils that are not subject to wind erosion because of

coarse fragments on the surface or because of surface

wetness.

Organic matter is the plant and animal residue in the soil

at various stages of decomposition. In table 16, the

estimated content of organic matter is expressed as a

percentage, by weight, of the soil material that is less than

2 millimeters in diameter.

The content of organic matter in 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 17 and 18 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 infiltration 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 is not considered flooding, nor is water in

swamps and marshes.

Table 17 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,

occasional, and frequent. None means that flooding is not

probable; rare that it is unlikely but possible under unusual

weather conditions; occasional that it occurs, on the

average, once or less in 2 years; and frequent that it

occurs, on the average, more than once in 2 years.

Duration is expressed as brief if less than 7 days, long if 7

days to 1 month, and very long if more than 1 month.

Probable dates are expressed in months.

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 17 are the depth to the seasonal high water table;

the kind of water table-that is, perched 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 17.

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. 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 in table 18 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 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 excavation.

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.

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 18 shows the expected initial subsidence,

which usually is a result of drainage, and total 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 the 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.
Soils in Whatcom County that are below an elevation of

approximately 800 feet are not usually subject to potential

frost action.

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 (43). 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.

Table 19 shows the classification of the soils in the survey

area. The categories are defined in the following

paragraphs.

ORDER. Eleven 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 Spodosol.

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 Orthod (Orth, meaning true, plus od,

from Spodosol).

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 Haplorthods (Hapl, meaning minimal

horizonation, plus orthod, a suborder of Spodosols).

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 Aqualfic identifies the subgroup that is

saturated with water at some time of the year and has an

argillic horizon. An example is Aqualfic Haplorthods.

FAMILY. Families are established within a subgroup on

the basis of physical and chemical properties and other

characteristics that affect management. Generally, 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-loamy, mixed, mesic Aqualfic Haplorthods.

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. 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 (41). Many, of the technical terms used in the

descriptions are defined in Soil Taxonomy (43). 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."

Barneston Series

The Barneston series consists of very deep, somewhat

excessively drained soils formed in a mixture of volcanic

ash and loess, over, glacial outwash. These
soils are on outwash terraces and terrace escarpments.

Slopes are 0 to 60 percent. The average annual

precipitation is 60 to 75 inches, and the mean annual air

temperature is about 47 degrees F.

These soils are sandy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Barneston gravelly loam, 0 to 8

percent slopes, 1 mile southeast of Kendall, 2,000 feet

north and 1,250 feet west of the southeast corner of sec.

35, T. 40 N., R. 5 E.

Oi-2.5 to 2 inches; undecomposed needles, leaves,

and twigs.

Oa-2 inches to 0; decomposed organic mat; many fine

and medium roots.

E-0 to 1.5 inches; brown (7.5YR 5/2) gravelly loam,

pinkish gray (7.5YR 6/2) dry; weak fine and medium

subangular blocky structure; slightly hard, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine, fine, and medium roots; many fine irregular pores;

about 20 percent pebbles; NaF pH 9.4; strongly acid;

clear smooth boundary.

Bs1-1.5 to 8 inches; dark brown (7.5YR 3/4) gravelly

loam, brown (7.5YR 5/4) dry; weak fine and medium

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many very fine, fine,

and medium roots; many fine irregular pores; about 30

percent pebbles; NaF pH 11.0; strongly acid; clear

wavy boundary.

Bs2-8 to 14 inches; dark brown (7.5YR 3/4) very gravelly

loam, light brown (7.5YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; common very fine and many

fine roots;. many fine irregular pores; about 45 percent

pebbles; NaF pH 11.5; strongly acid; clear wavy

boundary.

2C1-14 to 28 inches; dark yellowish brown (10YR 4/4)

extremely gravelly sand, light yellowish brown (10YR

6/4) dry; single grain; loose; many fine and few medium

roots; many medium and coarse irregular pores; about

70 percent pebbles and 5 percent cobbles; NaF pH

11.5; strongly acid; clear smooth boundary.

2C2-28 to 40 inches; olive brown (2.5Y 4/4) extremely

gravelly sand, light yellowish brown (2.5Y 6/4) dry;

single grain; loose; common fine and few medium roots;

many medium and coarse subangular pores; about 75

percent pebbles and 5 percent cobbles; moderately

acid; clear smooth boundary.

2C3-40 to 60 inches; dark grayish brown (2.5Y 4/2)

extremely gravelly sand, light brownish gray (2.5Y 6/2)

dry; single grain; loose; few medium roots; many

medium and coarse irregular pores; about 70

percent pebbles and 5 percent cobbles; moderately

acid.

The thickness of the solum and of the part of the profile

influenced by volcanic ash is 13 to 24 inches. The content

of clay in the lower part of the particle-size control section

is 0 to 3 percent. By weighted average, the upper part of

the control section has 35 to 60 percent pebbles and 0 to

10 percent cobbles and the lower part has 45 to 70

percent pebbles, 5 to 15 percent cobbles, and 0 to 15

percent stones.

The E horizon has hue of 7.5YR or 10YR, value of 2 to 5

when moist and 4 to 7 when dry, and chroma of 2 to 4

when moist and dry. Some pedons have an A horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3

to 5 when moist and 5 or 6 when dry, and chroma of 4 to

6 when moist and dry. It is gravelly loam, gravelly sandy

loam, very gravelly loam, or very gravelly sandy loam.

The 2C horizon has hue of 10YR or 2.5Y, value of 4 or

5 when moist and 6 or 7 when dry, and chroma of 2 to 6

when moist and dry. It is very gravelly loamy sand, very

gravelly sand, extremely gravelly loamy sand, or extremely

gravelly sand.

Barnhardt Series

The Barnhardt series consists of very deep, well

drained soils formed in a mixture of volcanic ash, loess,

and glacial outwash. These soils are on terraces. Slopes

are 0 to 5 percent. The average annual precipitation is

about 35 to 50 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are loamy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Barnhardt gravelly loam, 0 to 5

percent slopes, about 2 miles southwest of Everson,

250 feet south and 1,900 feet west of the northeast

corner of sec. 11, T. 39 N., R. 3 E.

Oi-1 inch to 0; undecomposed needles, leaves, and

twigs.

A-0 to 3 inches; dark brown (7.5YR 3/2) gravelly loam,

brown (10YR 5/3) dry; weak fine granular structure;

soft, very friable, nonsticky and nonplastic; weakly

smeary; many very fine and common fine roots; many

very fine irregular pores; about 20 percent

pebbles; NaF pH 10.0; slightly acid; clear wavy

boundary.

Bs1-3 to 9 inches; dark brown (7.5YR 4/4) gravelly

loam, light yellowish brown (10YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many
very fine and common fine roots; many very fine

irregular pores; about 25 percent pebbles; NaF pH

10.5; moderately acid; clear wavy boundary.

Bs2-9 to 21 inches; yellowish brown (10YR 5/4) extremely

gravelly loam, very pale brown (10YR 7/4) dry; weak fine

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many very fine,

common fine, and few medium roots; many very fine

irregular pores; about 60 percent pebbles; NaF pH

10.5; moderately acid; gradual wavy boundary.

BC-21 to 42 inches; yellowish brown (10YR 5/4) extremely

gravelly sandy loam, pale yellow (2.5Y 7/4) dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common very

fine, fine, medium, and coarse roots; many very fine

irregular pores; about 75 percent pebbles; NaF pH

10.5; moderately acid; gradual wavy boundary.

C-42 to 60 inches; yellowish brown (10YR 5/4) extremely

gravelly loam, very pale brown (10YR 7/4) dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; few very fine

roots; many very fine irregular pores; about 70 percent

pebbles; NaF pH 9.6; moderately acid.

The part of the profile influenced by volcanic ash is 60 or

more inches thick. The thickness of the solum is 8 to 30

inches. The particle-size control section has 50 to 75

percent pebbles and 0 to 5 percent cobbles by weighted

average.

The A horizon has hue of 7.5YR or 10YR, value of 3 or 4

when moist, and chroma of 2 to 4 when moist and dry.

The Bs horizon has hue of 7.5YR or 10YR and value of 4

or 5 when moist and 6 or 7 when dry. It is gravelly loam,

very gravelly loam, very gravelly silt loam, or extremely

gravelly loam.

The BC and C horizons have 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 and dry. Within the particle-size control

section, they are very gravelly loam, extremely gravelly

sandy loam, or very gravelly silt loam. Below the control

section, they are extremely gravelly loam, extremely

gravelly sandy loam, or extremely gravelly loamy sand.

Bellingham Series

The Bellingham series consists of very deep, poorly

drained soils formed in an admixture of loess, alluvium,

and lacustrine deposits. These soils are in depressions on

terraces. Slopes are 0 to 2 percent. The average

annual precipitation is 35 to 50 inches, and the mean

annual air temperature is about 50 degrees F.

These soils are fine, mixed, nonacid, mesic Mollic

Haplaquepts.

Typical pedon of Bellingham silty clay loam, 0 to 2

percent slopes, 1.5 miles north of Everson, 2,200 feet

south and 100 feet east of the northwest corner of sec. 19,

T. 40 N., R. 4 E.

Ap-0 to 10 inches; very dark grayish brown (10YR 3/2) silty

clay loam, brown (10YR 5/3) dry; moderate fine

subangular blocky structure; slightly hard, friable,

slightly sticky and plastic; many very fine and fine

roots; many very fine irregular pores; slightly acid; clear

smooth boundary.

Bg1-10 to 18 inches; very dark grayish brown (10YR 3/2)

and dark brown (10YR 4/3) silty clay loam, grayish

brown (10YR 5/2) and pale brown (10YR 6/3) dry;

common fine prominent mottles, yellowish brown

(10YR 5/6) moist and dry; moderate fine subangular

blocky structure; slightly hard, firm, slightly sticky and

plastic; common very fine and few fine roots; many

very fine irregular pores; few patchy clay films on

faces of peds; slightly acid; abrupt smooth boundary.

Bg2-18 to 24 inches; dark grayish brown (2.5Y 4/2) and

olive brown (2.5Y 4/4) silty clay loam, light gray (2.5Y

7/2) and pale yellow (2.5Y 7/4) dry; common medium

prominent yellowish brown (10YR 5/6) mottles, brownish

yellow (10YR 6/6) dry; weak coarse prismatic structure

parting to medium fine subangular blocky; very hard,

firm, slightly sticky and plastic; common very fine roots;

many very fine irregular pores; neutral; clear smooth

boundary.

CB-24 to 30 inches; grayish brown (2.5Y 5/2) silty clay

loam, light gray (2.5Y 7/2) dry; many medium distinct

light olive brown (2.5Y 5/4) mottles, light yellowish

brown (2.5Y 6/4) dry; moderate medium subangular

blocky structure; very hard, firm, slightly sticky and

plastic; few very fine roots; common very fine irregular

pores; few patchy clay films on faces of peds; neutral;

clear smooth boundary.

C1-30 to 38 inches; grayish brown (2.5Y 5/2) silty clay

loam, light gray (5Y 7/1) dry; common fine prominent

light olive brown (2.5Y 5/4) mottles, light yellowish

brown (2.5Y 6/4) dry; moderate coarse prismatic

structure parting to moderate medium subangular

blocky; very hard, firm, slightly sticky and plastic; few

very fine roots; neutral; clear smooth boundary.

C2-38 to 60 inches; grayish brown (2.5Y 5/2) silty clay

loam, white (2.5Y 8/2) dry; common fine prominent

light olive brown (2.5Y 5/4) mottles, light yellowish

brown (2.5Y 6/4) dry; moderate coarse prismatic
structure parting to moderate medium subangular

blocky; very hard, firm, slightly sticky and plastic; few

very fine roots; neutral.

The particle-size control section has 35 to 60 percent

clay by weighted average. The thickness of the solum is 10

to 30 inches.

The Ap horizon has value of 2 or 3 when moist and 4 or

5 when dry and chroma of 1 to 3 when moist and dry.

The Bg horizon has hue of 10YR, 2.5Y, or 5Y, value of 3

to 6 when moist and 5 to 8 when dry, and chroma of 1 to 3

when moist and dry. It is silty clay loam or silty clay.

The C horizon has hue of 2.5Y or 5Y, value of 5 or 6

when moist and 7 or 8 when dry, and chroma of 1 or 2

when moist and dry. It is dominantly silty clay loam, silty

clay, or clay. In some pedons, however, it has thin strata of

silt loam or sandy loam.

The Bellingham soils in this survey area are

taxadjuncts to the series because they have a mollic

epipedon. This difference, however, does not

significantly affect the use and management of the soils.

Birchbay Series

The Birchbay series consists of very deep, moderately

well drained soils formed in an admixture of loess and

volcanic ash over glaciofluvial deposits and glaciomarine

drift. These soils are on wave-reworked glaciomarine drift

plains. Slopes are 0 to 15 percent. The average annual

precipitation is 30 to 40 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are coarse-loamy over sandy or sandyskeletal, mixed, mesic Typic Haplorthods.

Typical pedon of Birchbay silt loam, 0 to 3 percent

slopes, 5 miles west of Ferndale, 2,400 feet south and

1,600 feet east of the northwest corner of sec. 16, T. 39

N., R. 1 E.

Ap-0 to 8 inches; dark brown (10YR 3/3) silt loam, dark

yellowish brown (10YR 4/4) dry; moderate medium

granular structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; many very fine and fine

roots; many very fine irregular pores; about 2 percent

pebbles; NaF pH 9.8; slightly acid; abrupt smooth

boundary.

Bs1-8 to 12 inches; dark brown (7.5YR 4/4) silt loam,

strong brown (7.5YR 5/6) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; common very fine and fine

roots; many very fine irregular pores; about 10

percent pebbles; NaF pH 10.5; moderately acid;

clear smooth boundary.

Bs2-12 to 24 inches; dark yellowish brown (10YR 4/4)

gravelly silt loam, brownish yellow (10YR 6/6) dry;

weak medium subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine roots; many very fine

irregular pores; about 20 percent pebbles; NaF pH

11.0; moderately acid; clear smooth boundary.

2C1-24 to 42 inches; dark yellowish brown (10YR 4/4)

very gravelly sand, brownish yellow (10YR 6/6) dry;

massive; slightly hard, very friable, nonsticky and

nonplastic; very few fine roots; many fine irregular

pores; about 35 percent pebbles and 5 percent

cobbles; NaF pH 11.0; moderately acid; clear wavy

boundary.

3C2-42 to 60 inches; light olive brown (2.5Y 5/4) loam,

pale yellow (2.5Y 7/4) dry; many large prominent strong

brown (7.5YR 5/6) mottles, reddish yellow (7.5YR 6/6)

dry; massive; very hard, firm, slightly sticky and slightly

plastic; few fine irregular pores; about 10 percent

pebbles; moderately acid.

The thickness of the part of the profile influenced by

volcanic ash and the depth to the 2C horizon are 14 to 32

inches. Depth to the 3C horizon is 40 to 60 inches.

The A horizon has hue of 7.5YR or 10YR, value of 2 to 4

when moist and 4 or 5 when dry, and chroma of 2 to 4

when moist and 3 or 4 when dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 or 6 when dry, and chroma of 4 to 6

when moist and dry. It is silt loam, loam, gravelly silt loam,

or gravelly loam.

The 2C horizon has hue of 10YR or 2.5Y, value of 3 to 5

when moist and 5 or 6 when dry, and chroma of 2 to 4

when moist and 2 to 6 when dry. It is very gravelly loamy

sand or very gravelly sand.

The 3C horizon has hue of 10YR to 5Y, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. It is dominantly loam, gravelly loam,

clay loam, gravelly clay loam, or silty clay loam. In some

pedons, however, it has thin strata of sandy loam.

Blainegate Series

The Blainegate series consists of very deep, poorly

drained soils formed in marine deposits. These soils are on

marine terraces. Slopes are 0 to 1 percent. The average

annual precipitation is 30 to 40 inches, and the mean

annual air temperature is about 50 degrees F.

These soils are very fine, mixed, mesic Typic

Argiaquolls.
Typical pedon of Blainegate silty clay, 0 to 1 percent

slopes, 1 mile east of Blaine, 2,600 feet south and 1,800

feet east of the northwest corner of sec. 5, T. 40 N., R. 1

E.

Ap-0 to 9 inches; very dark grayish brown (10YR 3/2) silty

clay, grayish brown (10YR 5/2) dry; few fine prominent

yellowish brown (10YR 5/8) mottles, brownish yellow

(10YR 6/8) dry; moderate medium granular structure;

slightly hard, friable, slightly sticky and plastic; many

very fine and common fine roots; many very fine

irregular pores; moderately acid; abrupt smooth

boundary.

Btg-9 to 27 inches; dark gray (5Y 4/1) clay, light gray (5Y

7/1) dry; many fine prominent yellowish brown (10YR

5/6) mottles, brownish yellow (10YR 6/6) dry; massive;

slightly hard, friable, sticky and plastic; many very fine

and common fine roots; many very fine irregular and

common very fine tubular pores; few patchy clay films

on faces of peds; slightly acid; clear smooth boundary.

C1-27 to 45 inches; gray (5Y 6/1) clay, white (5Y 8/1)

dry; many fine prominent yellowish brown (10YR 5/6)

mottles, brownish yellow (10YR 6/6) dry; massive; hard,

firm, sticky and plastic; common very fine roots; few

very fine irregular and common very fine tubular pores;

neutral; clear smooth boundary.

C2-45 to 60 inches; light brownish gray (2.5Y 6/2) clay,

white (2.5Y 8/2) dry; many coarse prominent light

olive brown (2.5Y 5/6) mottles, olive yellow (2.5Y

6/6) dry; massive; hard, firm, sticky and plastic;

common very fine roots; few very fine irregular and

common very fine tubular pores; neutral.

The particle-size control section has 60 to 75 percent

clay by weighted average. The thickness of the solum is 10

to 30 inches.

The Ap horizon has value of 2 or 3 when moist and 4 or

5 when dry and chroma of 1 to 3 when moist and dry. The

Bg horizon has hue of 10YR, 2.5Y, or 5Y, value of 3 to 6

when moist and 5 to 8 when dry, and chroma of 1 or 2

when moist and dry. The C horizon has hue of 2.5Y or 5Y,

value of 5 or 6 when moist and 7 or 8 when dry, and

chroma of 1 or 2 when moist and dry. In some pedons it

has thin strata of silt loam, silty clay loam, or sandy loam.

Blethen Series

The Blethen series consists of very deep, well drained

soils formed in glacial till, colluvium, and slope alluvium

with an admixture of volcanic ash and loess. These soils

are on side slopes and toe slopes of

foothills and landslides. Slopes are 5 to 60 percent. The

average annual precipitation is 50 to 70 inches, and the

mean annual air temperature is about 47 degrees F.

These soils are loamy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Blethen gravelly loam, 15 to 30 percent

slopes, 10 miles east of Lynden, 1,300 feet north and 500

feet east of the southwest corner of sec. 13, T. 40 N., R. 4

E.

Oi-0.75 to 0.25 inch; leaves, needles, twigs, and

cones.

Oa-0.25 inch to 0; decomposed needles, leaves, and

twigs; common very fine and fine roots.

A1-0 to 2 inches; dark brown (7.5YR 3/3) gravelly loam,

brown (7.5YR 4/3) dry; weak fine granular structure;

soft, very friable, nonsticky and slightly plastic; weakly

smeary; many very fine and fine and common medium

roots; many very fine irregular pores; about 15 percent

pebbles and 5 percent cobbles; NaF pH 9.8; slightly

acid; clear smooth boundary.

A2-2 to 6 inches; dark brown (7.5YR 3/3) gravelly loam,

strong brown (7.5YR 4/6) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

slightly plastic; weakly smeary; common very fine,

fine, and medium and few coarse roots; common

very fine irregular pores; about 15 percent pebbles

and 5 percent cobbles; NaF pH 10.1; moderately

acid; clear smooth boundary.

Bs1-6 to 18 inches; dark brown (7.5YR 4/4) very cobbly

loam, strong brown (7.5YR 5/6) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and slightly plastic; weakly smeary; common

very fine, fine, medium, and coarse roots; common

very fine irregular pores; about 25 percent pebbles

and 15 percent cobbles; NaF pH 10.1; moderately

acid; clear wavy boundary.

Bs2-18 to 28 inches; dark yellowish brown (10YR 4/4)

very cobbly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common fine and medium and few coarse roots;

common very fine irregular pores; about 25 percent

pebbles and 15 percent cobbles; NaF pH 10.5;

moderately acid; gradual smooth boundary.

Bs3-28 to 41 inches; dark yellowish brown (10YR 4/4)

very cobbly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; slightly hard,

very friable, nonsticky and nonplastic; weakly smeary;

few fine and medium roots; many very fine irregular

pores; about 30 percent pebbles and 20 percent

cobbles; NaF pH 10.1; moderately acid;
gradual smooth boundary.

C-41 to 60 inches; olive brown (2.5Y 4/4) very cobbly

loam, light yellowish brown (10YR 6/4) dry; massive;

hard, friable, nonsticky and nonplastic; weakly smeary;

few fine roots; few very fine irregular pores; about 40

percent pebbles and 20 percent cobbles; NaF pH 10.6;

slightly acid.

The thickness of the solum and of the part of the

profile influenced by volcanic ash is 26 to 50 inches.

The content of rock fragments in the control section

ranges from 35 to 60 percent. It includes 30 to 50

percent pebbles and 5 to 20 percent cobbles.

The A horizon has hue of 7.5YR or 10YR, value of 3 to 5

when moist and 4 to 7 when dry, and chroma of 2 or 3

when moist and 2 to 4 when dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 or 6 when dry, and chroma of 4 to 6

when moist and dry. It is very gravelly loam, very gravelly

silt loam, very cobbly loam, or very cobbly silt loam.

The C horizon has hue of 10YR or 2.5YR, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 3 or 4

when moist and dry. It is very gravelly loam, very gravelly

sandy loam, very cobbly loam, or very cobbly sandy loam.

Briscot Series

The Briscot series consists of very deep, poorly

drained soils that have been artificially drained. They

formed in alluvium on flood plains. Slopes are 0 to 2

percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are coarse-loamy, mixed, nonacid, mesic

Aeric Fluvaquents.

Typical pedon of Briscot silt loam, drained, 0 to 2

percent slopes, 3 miles south of Sumas, 400 feet south

and 2,400 feet east of the northwest corner of sec. 15, T.

40 N., R. 4 E.

Ap-0 to 9 inches; dark grayish brown (2.5Y 4/2) silt

loam, light gray (2.5Y 5/2) dry; moderate medium

subangular blocky structure parting to weak fine

granular; slightly hard, friable, slightly sticky and

slightly plastic; many very fine, common fine, and

few medium roots; many very fine irregular and

many very fine tubular pores; few fine pebbles;

moderately acid; abrupt smooth boundary.

C1-9 to 14 inches; dark grayish brown (2.5Y 4/2) silt

loam, light gray (2.5Y 7/2) dry; common fine

prominent yellowish brown (10YR 5/6) mottles,

brownish yellow (10YR 6/6) dry; moderate coarse

subangular blocky structure parting to weak fine

granular; slightly hard, friable, slightly sticky and

slightly plastic; many very fine, common fine, and

few medium roots; many very fine irregular and

many very fine tubular pores; moderately acid; abrupt

wavy boundary.

C2-14 to 22 inches; dark grayish brown (2.5Y 4/2) very

fine sandy loam, light gray (2.5Y 7/2) dry; many large

prominent yellowish brown (10YR 5/6) mottles,

brownish yellow (10YR 6/6) dry; massive; slightly hard,

friable, nonsticky and nonplastic; many very fine and

common fine roots; many very fine irregular and many

very fine tubular pores; moderately acid; abrupt smooth

boundary.

C3-22 to 34 inches; gray (5Y 6/1) fine sand, light gray

(5Y 7/1) dry; many large prominent olive brown (2.5Y

4/4) mottles, light yellowish brown (2.5Y 6/4) dry;

massive; soft, friable, nonsticky and nonplastic;

common very fine and few medium roots; many very

fine irregular pores; slightly acid; abrupt smooth

boundary.

C4-34 to 41 inches; gray (5Y 5/1) fine sandy loam, light

gray (5Y 7/1) dry; many large prominent olive brown

(2.5Y 4/4) mottles, light yellowish brown (2.5Y 6/4) dry;

massive; slightly hard, friable, nonsticky and

nonplastic; common very fine roots; many very fine

irregular pores; slightly acid; abrupt smooth boundary.

C5-41 to 60 inches; gray (5Y 5/1) and light brownish gray

(2.5Y 6/2) silt loam, light gray (5Y 7/1 and 2.5Y 7/2)

dry; many medium prominent yellowish brown (10YR

5/6) mottles, brownish yellow (10YR 6/6) dry; massive;

hard, friable, slightly sticky and slightly plastic; few very

fine roots; many very fine irregular and common very

fine tubular pores; slightly acid.

The control section is, by weighted average, 5 to 12

percent clay and 15 to 60 percent sand coarser than very

fine sand. These soils have an irregular distribution of

organic matter with increasing depth.

The A horizon has hue of 10YR or 2.5Y and value of 3 or

4 when moist and 6 or 7 when dry. The C horizon has hue

of 2.5Y or 5Y, value of 4 to 6 when moist and 7 when dry,

and chroma of 1 or 2 when moist and dry. It has mottles

with hue of 10YR or 2.5Y, value of 4 or 5 when moist, and

chroma of 4 to 6 when moist and dry. It is stratified silt

loam, very fine sandy loam, fine sandy loam, fine sand, or

sand.

Chuckanut Series

The Chuckanut series consists of deep and very deep,

well drained soils formed in a mixture of volcanic ash and

colluvium derived from glacial drift and
sandstone. These soils are on foothill side slopes, back

slopes, toe slopes, and landslides. Slopes are 3 to 60

percent. The average annual precipitation is 35 to 60

inches, and the mean annual air temperature is about 49

degrees F.

These soils are coarse-loamy, mixed, mesic Typic

Haplorthods.

Typical pedon of Chuckanut loam, 3 to 8 percent slopes,

3 miles southwest of Van Zandt, 1,000 feet south and 900

feet east of the northwest corner of sec. 19, T. 38 N., R. 4

E.

Ap-0 to 10 inches; dark brown (10YR 4/3) loam, brown

(10YR 5/3) dry; weak fine granular structure; soft, very

friable, nonsticky and nonplastic; weakly smeary; many

very fine roots; many very fine irregular pores; few soft

pebbles; NaF pH 11.0; moderately acid; clear smooth

boundary.

Bw1-10 to 12 inches; olive brown (2.5Y 4/4) sandy

loam, pale yellow (2.5Y 7/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common

very fine roots; few soft pebbles; NaF pH 11.0;

moderately acid; clear smooth boundary.

Bw2-12 to 24 inches; dark brown (10YR 3/3) gravelly

loam, pale brown (10YR 6/3) dry; weak fine subangular

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; common very fine roots; many very

fine irregular pores; about 15 percent hard pebbles

and 5 percent soft pebbles; NaF pH 10.2; moderately

acid; clear smooth boundary.

C-24 to 60 inches; olive brown (2.5Y 4/4) gravelly sandy

loam, pale yellow (2.5Y 7/4) dry; weak medium

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very

fine roots; many very fine irregular pores; about 20

percent hard pebbles and 60 percent soft pebbles;

NaF pH 10.2; slightly acid.

The depth to sandstone is 40 to more than 60 inches.

By weighted average, the content of rock fragments in the

control section is 0 to 15 percent hard pebbles, 35 to 60

percent soft pebbles, and 0 to 5 percent hard cobbles.

The A horizon has hue of 7.5YR or 10YR, value of 2 to 4

when moist and 4 to 6 when dry, and chroma of 2 or 3

when moist and 2 to 4 when dry.

The Bw horizon has hue of 7.5YR to 2.5Y, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 3 or 4

when moist and dry. It is gravelly loam, gravelly sandy

loam, or gravelly fine sandy loam.

The C 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 and dry. It is gravelly loam or gravelly

sandy loam.

Clendenen Series

The Clendenen series consists of shallow, moderately

well drained soils formed in a mixture of volcanic ash,

loess, and colluvium over glacial till. These soils are on

mountain back slopes and shoulder slopes. Slopes are 5 to

30 percent. The average annual precipitation is 80 to 100

inches, and the mean annual air temperature is about 41

degrees F.

These soils are loamy-skeletal, mixed, shallow Humic

Cryorthods.

Typical pedon of Clendenen gravelly silt loam, 5 to 30

percent slopes, 800 feet north and 800 feet west of the

southeast corner of sec. 33, T. 38 N., R. 6 E.

Oi-7 to 3 inches; undecomposed needles, leaves, and

twigs.

Oa-3 inches to 0; decomposed forest litter; many fine,

medium, and coarse roots.

E-0 to 2 inches; reddish gray (5YR 5/2) gravelly silt

loam, pinkish gray (5YR 6/2) dry; massive; slightly

hard, friable, nonsticky and nonplastic; weakly

smeary; about 20 percent pebbles; many very fine

roots; common fine irregular pores; very strongly acid;

abrupt smooth boundary.

Bhs-2 to 5 inches; strong brown (7.5YR 4/6) gravelly silt

loam, strong brown (7.5YR 5/6) dry; dark brown (7.5YR

3/2) organic stains, dark brown (7.5YR 4/4) dry;

moderate medium subangular blocky structure; slightly

hard, firm, nonsticky and nonplastic; weakly smeary;

common fine and medium roots; common very fine

irregular pores; about 15 percent pebbles; strongly

acid; clear smooth boundary.

Bs-5 to 16 inches; strong brown (7.5YR 5/6) very

gravelly silt loam, reddish yellow (7.5YR 6/6) dry;

moderate fine and medium subangular blocky

structure; slightly hard, firm, nonsticky and

nonplastic; weakly smeary; about 40 percent

pebbles; few fine roots; many very fine irregular

pores; moderately acid; abrupt smooth boundary.

2Cd-16 to 60 inches; pale brown (10YR 6/3), dense

glacial till that breaks to very gravelly loam, very pale

brown (10YR 7/3) dry; yellowish red (5YR 4/6) organic

stains, yellowish red (5YR 5/6) dry; massive; hard,

firm, slightly sticky and slightly plastic; about 50

percent pebbles; moderately acid.

The depth to dense, compact glacial till is 14 to 20

inches. The content of rock fragments in the control

section ranges from 40 to 65 percent.

The E horizon has hue of 5YR or 7.5YR and value of
4 or 5 when moist and 6 or 7 when dry.

The Bhs and Bs horizons have hue of 5YR or 7.5YR,

value of 3 or 4 when moist and 5 or 6 when dry, and

chroma of 4 to 6 when moist and dry. The fine-earth

fraction is loam or silt loam.

The 2Cd horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry. It is dense glacial till that breaks to

very gravelly loam or very gravelly sandy loam.

Clipper Series

The Clipper series consists of very deep, somewhat

poorly drained soils formed in an admixture of loess and

volcanic ash over glacial outwash. These soils are in

depressions on outwash terraces and outwash plains.

Slopes are 0 to 2 percent. The average annual precipitation

is 35 to 55 inches, and the mean annual air temperature is

about 50 degrees F.

These soils are coarse-loamy, mixed, mesic Aquic

Haplorthods.

Typical pedon of Clipper silt loam, drained, 0 to 2

percent slopes, 4 miles northeast of Lynden, 500 feet

north and 2,400 feet east of the southwest corner of sec.

34, T. 41 N., R. 3 E.

Ap-0 to 9 inches; very dark grayish brown (10YR 3/2) silt

loam, light brownish gray (10YR 6/2) dry; moderate

medium subangular blocky structure; hard, firm, slightly

sticky and slightly plastic; many very fine roots; many

very fine irregular and few fine tubular pores; about 5

percent pebbles; NaF pH 9.4; slightly acid; abrupt

smooth boundary.

E1-9 to 18 inches; grayish brown (2.5Y 5/2) and gray

(10YR 6/1) silt loam, light gray (2.5Y 7/2) and white

(10YR 8/1) dry; many medium prominent yellowish

brown (10YR 5/6) mottles, brownish yellow (10YR 6/6)

dry; moderate medium subangular blocky structure;

hard, friable, slightly sticky and slightly plastic;

common very fine roots; many very fine irregular and

few very fine tubular pores; few pebbles; strongly acid;

abrupt smooth boundary.

2E2-18 to 22 inches; grayish brown (2.5Y 5/2) and gray

(10YR 5/1) gravelly sandy loam, light gray (2.5Y 7/2 and

10YR 7/1) dry; many medium prominent strong brown

(7.5YR 5/8) mottles, reddish yellow (7.5YR 6/8) dry;

moderate medium subangular blocky structure; hard,

friable, slightly sticky and slightly plastic; few very fine

roots; many very fine irregular pores; about 30 percent

pebbles; moderately acid; clear smooth boundary.

2Bs-22 to 30 inches; yellowish brown (10YR 5/8) very

gravelly sandy loam, brownish yellow (10YR 6/8)

dry; many medium prominent grayish brown (2.5Y

5/2) mottles, light gray (2.5Y 7/2) dry; moderate

medium subangular blocky structure; slightly hard,

friable, slightly sticky and slightly plastic; very few

very fine roots; many very fine irregular pores; about

30 percent pebbles; moderately acid; clear smooth

boundary.

3C1-30 to 37 inches; dark grayish brown (2.5Y 4/2) and

grayish brown (2.5Y 5/2) very gravelly loamy sand,

light gray (2.5Y 7/2) dry; few fine prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; slightly hard, friable,

nonsticky and nonplastic; many very fine irregular

pores; about 50 percent pebbles and 5 percent

cobbles; moderately acid; clear smooth boundary.

3C2-37 to 60 inches; dark grayish brown (2.5Y 4/2) very

gravelly loamy sand, light brownish gray (2.5Y 6/2) dry;

many fine prominent yellowish brown (10YR 5/6)

mottles, brownish yellow (10YR 6/6) dry; massive; soft,

friable, nonsticky and nonplastic; many very fine

irregular pores; about 50 percent pebbles and 5

percent cobbles; moderately acid.

The thickness of the solum is 14 to 30 inches. By

weighted average, the solum has 10 to 18 percent clay

and the particle-size control section ranges from 15 to 35

percent rock fragments. The content of rock fragments

increases with increasing depth. It ranges from 10 to 25

percent in the solum and from 25 to 60 percent in the

substratum.

The A horizon has chroma of 2 or 3 when moist and dry.

The E horizon has hue of 10YR to 5Y, value of 5 or 6 when

moist and 7 or 8 when dry, and chroma of 1 or 2 when

moist and dry. It is silt loam, loam, gravelly loam, or

gravelly silt loam. The 2E horizon has hue of 10YR to 5Y,

value of 5 or 6 when moist and 7 or 8 when dry, and

chroma of 1 or 2 when moist and dry. It is mottled. It is

gravelly sandy loam or gravelly loam.

The 2Bs horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 6 or 7 when dry, and chroma of 1 to 8

when moist and dry. It is gravelly loam, gravelly sandy

loam, very gravelly loam, or very gravelly sandy loam.

The 3C horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry. It is massive or single grain and is

loose, soft, or slightly hard. It is very gravelly loamy sand

or very gravelly sand.

Comar Series

The Comar series consists of deep, moderately well

drained soils formed in a mixture of volcanic ash,
colluvium, and slope alluvium derived from siltstone and

glacial till. These soils are on foothill back slopes and toe

slopes. Slopes are 5 to 60 percent. The average annual

precipitation is 50 to 65 inches, and the mean annual

temperature is about 47 degrees F.

These soils are fine-loamy, mixed, mesic Typic

Haplorthods.

Typical pedon of Comar silt loam, 30 to 60 percent

slopes, 1.5 miles northeast of Deming, 2,200 feet due

south of the northwest corner of sec. 29, T. 39 N., R. 5 E.

Oi-5 to 4 inches; undecomposed needles, leaves, and

twigs.

Oa-4 inches to 0; decomposed forest litter; many very

fine, fine, medium, and coarse roots.

A-0 to 5 inches; dark brown (10YR 3/3) silt loam, brown

(10YR 5/3) dry; weak fine subangular blocky structure;

soft, very friable, slightly sticky and slightly plastic;

weakly smeary; many very fine, fine, medium, and

coarse roots; many fine irregular pores; about 30

percent weathered pebbles and 10 percent

unweathered pebbles; NaF pH 10.0; moderately acid;

clear smooth boundary.

Bs-5 to 16 inches; brown (10YR 4/3) silt loam,

yellowish brown (10YR 5/4) dry; weak fine subangular

blocky structure; soft, very friable, slightly sticky and

slightly plastic; weakly smeary; many very fine and

fine and common medium and coarse roots; many

fine irregular pores; about 20 percent weathered

pebbles and 5 percent unweathered pebbles; NaF pH

10.5; moderately acid; clear smooth boundary.

2C1-16 to 39 inches; light olive brown (2.5Y 5/4) silt

loam, very pale brown (10YR 7/3) dry; massive; very

hard, firm, sticky and plastic; many very fine and fine

and few medium roots; many fine and medium irregular

pores; about 75 percent weathered pebbles; NaF pH

9.4; strongly acid; clear smooth boundary.

2C2-39 to 44 inches; light olive brown (2.5Y 5/4) silt

loam; pale yellow (2.5YR 7/4) dry; massive; very hard,

firm, sticky and plastic; common very fine and fine and

few medium roots; many fine and medium irregular

pores; about 60 percent weathered pebbles; strongly

acid; abrupt wavy boundary.

2Cr-44 inches; siltstone.

The depth to siltstone is more than 40 inches. The

lower part of the control section has 20 to 30 percent

clay. The thickness of the part of the profile influenced by

volcanic ash is 14 to 24 inches. The content of rock

fragments in the particle-size control section ranges

from 0 to 25 percent unweathered pebbles and 15 to 80

percent weathered pebbles.

The A horizon has chroma of 3 or 4 when moist and

dry. The Bs horizon has value of 5 or 6 when dry and

chroma of 3 or 4 when moist and dry. It is loam or silt

loam. The 2C horizon has hue of 10YR or 2.5Y, value of 4

or 5 when moist and 5 to 8 when dry, and chroma of 3 or

4 when moist and dry. It is silt loam, silty clay loam, or

gravelly silt loam.

Crinker Series

The Crinker series consists of moderately deep, well

drained soils formed in an admixture of volcanic ash,

colluvium, slope alluvium, and glacial till derived dominantly

from phyllite. These soils are on high mountain back slopes

and shoulder slopes. Slopes are 30 to 60 percent. The

average annual precipitation is 80 to 95 inches, and the

mean annual air temperature is about 42 degrees F.

These soils are loamy-skeletal, mixed Typic

Cryorthods.

Typical pedon of Crinker very channery silt loam, 30 to

60 percent slopes, 5.5 miles east of Acme, 1,000 feet north

and 1,500 feet west of the southeast corner of sec. 7, T. 37

N., R. 6 E.

Oa-6 inches to 0; decomposed needles, leaves, and

twigs; many very fine, fine, medium, and coarse roots.

E1-0 to 3 inches; dark brown (7.5YR 4/2) very channery

loam, pinkish gray (7.5YR 7/2) and light gray (10YR

7/1) dry; massive; slightly hard, friable, slightly sticky

and slightly plastic; few very fine roots; many very fine

irregular pores; about 35 percent channers; extremely

acid; clear smooth boundary.

E2-3 to 6 inches; reddish brown (5YR 5/3) very

channery silt loam, pinkish gray (5YR 7/2) dry;

massive; slightly hard, friable, slightly sticky and

slightly plastic; few very fine roots; many very fine

irregular pores; about 40 percent channers; extremely

acid; abrupt smooth boundary.

Bhs-6 to 9 inches; strong brown (7.5YR 5/6) very

channery silt loam, brownish yellow (10YR 6/6) dry;

dark reddish brown (5YR 2/2) organic stains, very dark

gray (5YR 3/1) dry; massive; hard; very firm, nonsticky

and nonplastic; weakly smeary; many very fine irregular

pores; about 50 percent channers; NaF pH 11.0; very

strongly acid; clear smooth boundary.

Bs1-9 to 18 inches; yellowish brown (10YR 5/6) very

channery silt loam, brownish yellow (10YR 6/6) dry;

dark reddish brown (5YR 2/2) organic stains, dark
reddish brown (5YR 3/2) dry; massive; very hard, very

firm, nonsticky and nonplastic; weakly smeary; common

very fine irregular pores; about 55 percent channers;

NaF pH 12.0; strongly acid; clear smooth boundary.

Bs2-18 to 24 inches; yellowish brown (10YR 5/4) very

channery silt loam, light yellowish brown (10YR 6/4)

dry; dark reddish brown (5YR 2/2) organic stains, dark

reddish brown (5YR 3/2) dry; weak fine subangular

blocky structure; slightly hard, firm, slightly sticky and

slightly plastic; weakly smeary; many very fine irregular

pores; about 60 percent channers; NaF pH 12.0; very

strongly acid; clear smooth boundary.

R-24 inches; phyllite.

The depth to phyllite is 20 to 40 inches. The content of

hard phyllite rock fragments in the particle-size control

section ranges from 40 to 60 percent.

The E horizon has hue of 5YR, 7.5YR, or 10YR,

value of 4 or 5 when moist and 6 or 7 when dry, and

chroma of 1 to 3 when moist and dry.

The Bhs horizon has hue of 5YR, 7.5YR, or 10YR,

value of 3 to 5 when moist and 5 to 7 when dry, and

chroma of 4 to 6 when moist and dry. It is very channery

loam or very channery silt loam.

The Bs horizon has hue of 7.5YR or 10YR, value of 4 or 5

when moist and 5 to 7 when dry, and chroma of 4 to 6

when moist and dry. It is very channery loam or very

channery silt loam.

Some pedons have a C horizon. This horizon has hue

of 2.5Y or 5Y, value of 4 to 6 when moist and 6 to 8

when dry, and chroma of 4 to 6 when moist and dry. It is

very channery loam or extremely channery loam.

Cupples Series

The Cupples series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash and loess over glacial till. These soils are on

mountain back slopes and plateaus. Slopes are 5 to 60

percent. The average annual precipitation is 60 to 80

inches, and the mean annual air temperature is about 44

degrees F.

These soils are loamy-skeletal, mixed, frigid Typic

Haplorthods.

Typical pedon of Cupples gravelly loam, 5 to 30 percent

slopes, 5 miles northeast of Deming, 2,200 feet north and

2,400 feet west of the southeast corner of sec. 23, T. 39

N., R. 5 E.

Oi-7 to 5 inches; undecomposed needles and twigs. Oa-5

inches to 0; decomposed forest litter; many very fine,

fine, medium, and coarse roots.

E-0 to 2 inches; dark brown (7.5YR 4/2) gravelly fine

sandy loam, pinkish gray (7.5YR 6/2) dry; massive;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; many very fine and fine, common medium, and

few coarse roots; common very fine irregular pores;

about 15 percent pebbles and 5 percent cobbles; very

strongly acid; abrupt smooth boundary.

Bhs-2 to 5 inches; dark brown (7.5YR 3/4) and dark

yellowish brown (10YR 3/4) gravelly silt loam, strong

brown (7.5YR 5/6) and light yellowish brown (10YR 6/4)

dry; dark reddish brown (5YR 3/2) organic stains, dark

reddish brown (5YR 3/3) dry; moderate medium and

coarse subangular blocky structure; hard, very firm,

nonsticky and nonplastic; weakly smeary; common fine

and medium roots; common very fine irregular pores;

about 20 percent hard pebbles, 20 percent soft

pebbles, and 5 percent cobbles; strongly acid; abrupt

smooth boundary.

Bs-5 to 10 inches; dark brown (7.5YR 3/4) gravelly loam,

light yellowish brown (10YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many very fine and fine

and common medium and coarse roots; many very fine

irregular pores; about 10 percent hard pebbles, 30

percent soft pebbles, and 5 percent cobbles;

moderately acid; clear wavy boundary.

BC1-10 to 21 inches; olive brown (2.5Y 4/4) very gravelly

loam, yellowish brown (10YR 5/4) dry; weak medium

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many very fine and fine

and few medium and coarse roots; many very fine

irregular pores; about 30 percent hard pebbles, 25

percent soft pebbles, and 5 percent cobbles; slightly

acid; abrupt wavy boundary.

BC2-21 to 30 inches; dark yellowish brown (10YR 4/4)

very gravelly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common fine

and medium roots; many very fine irregular pores; about

40 percent hard pebbles; slightly acid; abrupt smooth

boundary.

2Cd-30 to 60 inches; light olive brown (2.5Y 5/4),

dense glacial till that breaks to very gravelly sandy

loam, pale yellow (2.5Y 7/4) dry; hard, friable,

nonsticky and nonplastic; about 45 percent hard

pebbles, 15 percent soft pebbles, and 5 percent

cobbles; slightly acid.

The depth to dense, compact glacial till is 20 to 40

inches. The content of rock fragments in the particle-
size control section ranges from 35 to 45 percent hard

pebbles, 5 to 25 percent soft pebbles, and 0 to 5 percent

cobbles.

The E horizon has hue of 7.5YR or 10YR and value of 3

or 4 when moist and 6 or 7 when dry.

The Bhs and Bs horizons have hue of 7.5YR or 10YR,

value of 3 or 4 when moist and 5 or 6 when dry, and

chroma of 4 to 6 when moist and dry. They are gravelly

loam or gravelly silt loam.

The BC horizon has hue of 10YR or 2.5Y and value of 4

or 5 when moist and 5 or 6 when dry.

The 2Cd horizon has value of 4 or 5 when moist and 6

or 7 when dry. It is dense glacial till that breaks to very

gravelly loam or very gravelly sandy loam.

Dekapen Series

The Dekapen series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash and loess over glacial till derived from

sandstone. These soils are on mountain plateaus and

back slopes. Slopes are 8 to 25 percent. The average

annual precipitation is 60 to 75 inches, and the mean

annual air temperature is about 44 degrees F.

These soils are coarse-loamy, mixed, frigid Typic

Haplorthods.

Typical pedon of Dekapen loam, 8 to 25 percent slopes,

2 miles southeast of Van Zandt, 1,700 feet north and 2,400

feet west of the southeast corner of sec. 15, T. 38 N., R. 5

E.

Oi-1 to 0.25 inch; undecomposed needles, leaves, and

twigs.

Oa-0.25 inch to 0; decomposed forest litter; many

medium roots.

E-0 to 2 inches; dark brown (7.5YR 3/2) gravelly silt

loam, pinkish gray (7.5YR 6/2) dry; weak fine

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; many fine and medium roots;

many fine irregular pores; about 10 percent soft

pebbles and 15 percent hard pebbles; strongly acid;

abrupt wavy boundary.

Bhs-2 to 8 inches; dark brown (7.5YR 3/4) loam, light

brown (10YR 6/4) dry; dark reddish brown (5YR 3/2)

organic stains, dark brown (7.5YR 4/4) dry; weak fine

and medium subangular blocky structure; slightly hard,

firm, nonsticky and nonplastic; weakly smeary; many

very fine and medium roots; common fine irregular

pores; about 40 percent soft pebbles, 10 percent soft

cobbles, and 5 percent hard pebbles; strongly acid;

clear wavy boundary.

Bs1-8 to 18 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 nonplastic; weakly smeary; many

very fine and fine and few medium roots; many fine

irregular pores; about 25 percent soft pebbles and 10

percent hard pebbles; strongly acid; clear wavy

boundary.

Bs2-18 to 24 inches; dark yellowish brown (10YR 3/4)

loam, yellowish brown (10YR 5/4) dry; weak medium

subangular blocky structure; slightly hard, friable,

slightly sticky and nonplastic; weakly smeary; many

very fine and fine roots; many medium irregular and

common medium tubular pores; about 30 percent soft

pebbles and 5 percent hard pebbles; strongly acid;

clear smooth boundary.

2C-24 to 31 inches; olive brown (2.5Y 4/4) loam, pale

yellow (2.5Y 7/4) dry; common fine distinct dark brown

(7.5YR 4/4) mottles, brown (7.5YR 5/4) dry; massive;

soft, friable, nonsticky and nonplastic; common very

fine and many fine and medium irregular and common

fine tubular pores; about 30 percent soft pebbles and

5 percent hard pebbles; strongly acid; abrupt smooth

boundary.

2Cd-31 to 60 inches; light olive brown (2.5Y 5/4), dense

glacial till that breaks to loam, pale yellow (2.5Y 7/4)

dry; common fine prominent strong brown (7.5YR 5/8)

mottles, reddish yellow (7.5YR 6/8) dry; massive; very

hard, very firm, nonsticky and nonplastic; few very fine

irregular pores; about 15 percent soft pebbles and 5

percent hard pebbles; strongly acid.

The thickness of the solum and of the part of the profile

influenced by volcanic ash is 24 to 32 inches. The depth to

dense, compact glacial till is 24 to 40 inches. By weighted

average, the content of rock fragments in the particle-size

control section is 25 to 40 percent soft pebbles, 0 to 15

percent soft cobbles, and 5 to 15 percent hard pebbles.

The E horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs and Bs horizons have hue of 7.5YR or

10YR, value of 3 to 5 when moist and 5 to 7 when dry, and

chroma of 4 to 6 when moist and dry. They are loam or

sandy loam.

The C horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry. It is loam or sandy loam.

The 2Cd horizon is dense glacial till that breaks to loam

or sandy loam. It has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry.
Deming Series

The Deming series consists of very deep, well drained

soils formed in a mixture of volcanic ash, slope alluvium,

and colluvium over unconsolidated glacial till. The slope

alluvium, colluvium, and glacial till are derived from

sandstone, conglomerate, metasedimentary rocks, and

volcanic rocks. These soils are on mountain back slopes.

Slopes are 5 to 60 percent. The average annual

precipitation is 80 to 95 inches, and the mean annual air

temperature is about 40 degrees F.

These soils are loamy-skeletal, mixed Humic

Cryorthods.

Typical pedon of Deming gravelly silt loam, 30 to 60

percent slopes, 6 miles northeast of Glacier, 1,900 feet

north and 800 feet west of the southeast corner of sec. 10,

T. 40 N., R. 6 E.

Oi-4 inches to 1 inch; undecomposed needles, twigs,

leaves, wood fragments, and moss.

Oa-1 inch to 0; decomposed needles, twigs, and

leaves; many very fine, fine, medium, and coarse

roots.

E-0 to 3 inches; dark brown (7.5YR 4/2) gravelly silt

loam, pinkish gray (7.5YR 6/2) dry; massive; slightly

hard, friable, nonsticky and nonplastic; many very fine

and fine and common medium and coarse roots; many

very fine irregular pores; about 20 percent pebbles and

5 percent cobbles; extremely acid; abrupt smooth

boundary.

Bhs-3 to 8 inches; dark reddish brown (5YR 3/4) gravelly

silt loam, yellowish red (5YR 4/6) dry; dark reddish

brown (5YR 2/2) organic stains on faces of peds, dark

brown (7.5YR 3/3) dry; moderate fine subangular

blocky structure; slightly hard, friable,. nonsticky and

nonplastic; weakly smeary; many fine and common

very fine, medium, and coarse roots; common very fine

irregular pores; about 20 percent pebbles and 5

percent cobbles; NaF pH less than 9.0; very strongly

acid; abrupt smooth boundary.

Bs1-8 to 15 inches; strong brown (7.5YR 4/6) very

gravelly loam, strong brown (7.5YR 5/6) dry; weak fine

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many fine and medium

and common very fine and coarse roots; common very

fine irregular pores; about 35 percent pebbles and 5

percent cobbles; NaF pH 11.5; strongly acid; clear wavy

boundary.

Bs2-15 to 24 inches; dark brown (7.5YR 4/4) very

gravelly sandy loam, yellowish brown (10YR 5/6)

dry; weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine and few

medium roots; common very fine irregular pores;

about 45 percent pebbles and 10 percent cobbles;

NaF pH 11.5; very strongly acid; clear wavy

boundary.

BC-24 to 37 inches; dark yellowish brown (10YR 3/4)

extremely gravelly sandy loam, dark yellowish brown

(10YR 4/4) dry; massive; soft, very friable, nonsticky

and nonplastic; weakly smeary; common very fine and

fine and few medium roots; many very fine irregular

pores; about 50 percent pebbles, 10 percent cobbles,

and 5 percent stones; NaF pH 11.0; very strongly acid;

clear smooth boundary.

2C-37 to 60 inches; dark yellowish brown (10YR 4/4)

extremely gravelly loamy sand, light yellowish brown

(10YR 6/4) dry; massive; soft, very friable, nonsticky

and nonplastic; weakly smeary; few fine roots; many

fine irregular pores; about 60 percent pebbles and 5

percent cobbles; NaF pH 10.5; strongly acid.

The thickness of the part of the profile influenced by

volcanic ash is more than 40 inches. The thickness of the

solum is 24 to 40 inches. The content of rock fragments in

the control section ranges from 45 to 60 percent.

The E horizon has hue of 5YR or 7.5YR, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs horizon has hue of 5YR or 7.5YR, value of 3

or 4 when moist and 3 to 5 when dry, and chroma of 4 to

6 when moist and dry.

The Bs and BC horizons have hue of 7.5YR or 10YR,

value of 3 or 4 when moist and 4 or 5 when dry, and

chroma of 3 to 6 when moist and dry. They are very

gravelly loam, very gravelly sandy loam, or extremely

gravelly sandy loam.

The C horizon has hue of 10YR or 2.5Y, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 2 to 6

when moist and dry. It is very gravelly loam, very gravelly

sandy loam, or extremely gravelly loamy sand.

Diobsud Series

The Diobsud series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash and colluvium over glacial till derived from

phyllite. These soils are on mountain back slopes and

ridges. Slopes are 30 to 60 percent. The average annual

precipitation is 85 to 95 inches, and the mean annual air

temperature is about 42 degrees F.

These soils are coarse-loamy, mixed Humic

Cryorthods.

Typical pedon of Diobsud gravelly silt loam, 30 to 60

percent slopes, 9.5 miles east of Wickersham, 2,600
feet south and 100 feet east of the northwest corner of

sec. 35, T. 37 N., R. 6 E.

Oa-7 to 3 inches; undecomposed needles, leaves, and

twigs.

Oi-3 inches to 0; decomposed needles, leaves, and

twigs; many very fine and fine and few medium

roots.

E-0 to 4 inches; dark brown (7.5YR 3/2) gravelly silt

loam, pinkish gray (7.5YR 6/2) dry; massive; soft,

friable, nonsticky and nonplastic; common very fine,

fine, and medium roots; many very fine irregular pores;

about 30 percent pebbles; extremely acid; abrupt

smooth boundary.

Bhs-4 to 11 inches; dark brown (7.5YR 3/4) gravelly silt

loam, brown (7.5YR 5/4) dry; reddish brown (5YR 5/4)

organic stains, light reddish brown (5YR 6/4) dry;

moderate coarse subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine and few medium roots; many

very fine irregular pores; about 30 percent pebbles;

NaF pH 10.0; very strongly acid; abrupt irregular

boundary.

Bs-11 to 16 inches; strong brown (7.5YR 4/6) gravelly silt

loam, reddish yellow (7.5YR 6/6) dry; moderate coarse

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very fine,

fine, and medium roots; many very fine irregular pores;

about 25 percent pebbles; NaF pH 12.0; strongly acid;

clear irregular boundary.

BC-16 to 20 inches; brown (10YR 5/3) gravelly silt loam,

pale brown (10YR 6/3) dry; moderate medium

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very fine

and fine roots; many very fine irregular pores; about 30

percent pebbles; NaF pH 12.0; strongly acid; clear

smooth boundary.

C-20 to 37 inches; olive gray (5Y 5/2) gravelly loam, light

olive gray (5Y 6/2) dry; massive; slightly hard, friable,

nonsticky and nonplastic; very few very fine roots;

common very fine irregular pores; about 30 percent

pebbles; NaF pH 12.0; strongly acid; abrupt smooth

boundary.

2Cd-37 to 60 inches; olive gray (5Y 4/2), dense glacial till

that breaks to very gravelly loam, light olive gray (5Y

6/2) dry; massive; hard, firm, nonsticky and nonplastic;

about 45 percent pebbles; NaF pH 12.0; strongly acid.

The depth to dense, compact glacial till is 20 to 40

inches. The particle-size control section ranges from 20 to

35 percent hard phyllite fragments.

The E horizon has hue of 7.5YR or 10YR, value of 3

to 5 when moist and 6 to 8 when dry, and chroma of 1 or

2 when moist and dry.

The Bhs and Bs horizons have hue of 5YR or 7.5YR,

value of 3 to 5 when moist and 5 or 6 when dry, and

chroma of 4 to 6 when moist and dry. They are gravelly

loam or gravelly silt loam.

The BC horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 to 8 when dry, and chroma of 2 or 3

when moist and dry. It is gravelly loam or gravelly silt

loam.

The C horizon has hue of 2.5Y or 5Y, value of 4 or 5

when moist and 6 to 8 when dry, and chroma of 1 to 3

when moist and dry. It is gravelly loam or gravelly clay

loam.

The 2Cd horizon is dense glacial till that breaks to

gravelly loam or very gravelly loam. It has hue of 2.5Y or

5Y, value of 4 or 5 when moist and 5 to 7 when dry, and

chroma of 2 to 4 when moist and dry.

Edfro Series

The Edfro series consists of shallow, moderately well

drained soils formed in a mixture of volcanic ash, loess,

and colluvium over glacial till derived from dunite. These

soils are on high mountain shoulder slopes and back

slopes. Slopes are 8 to 60 percent. The average annual

precipitation is 85 to 105 inches, and the mean annual

temperature is about 41 degrees F.

These soils are loamy-skeletal, serpentinitic, shallow

Typic Cryorthods.

Typical pedon of Edfro very gravelly silt loam, 30 to 60

percent slopes, 7 miles east of Acme, 1,700 feet south

and 1,700 feet east of the northwest corner of sec. 4, T.

37 N., R. 6 E.

Oi-4 to 3.5 inches; needles, leaves, and twigs.

 Oa-3.5 inches to 0; decomposed needles, twigs, and

 bark; many very fine and common fine roots.

E-0 to 3 inches; brown (7.5YR 5/2) very gravelly silt

loam, pinkish gray (7.5YR 7/2) dry; massive; soft,

very friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine roots; many very fine

irregular pores; about 30 percent pebbles and 5

percent cobbles; NaF pH 10.0; extremely acid; abrupt

wavy boundary.

Bhs1-3 to 7 inches; strong brown (7.5YR 4/6) very

gravelly silt loam, strong brown (7.5YR 5/8) dry; dark

reddish brown (2.5YR 3/4) organic stains on faces of

peds, yellowish red (5YR 4/6) dry; moderate medium

and coarse subangular blocky structure; hard, very

firm, nonsticky and nonplastic; weakly smeary;

common very fine roots; many very fine irregular

pores; about 45 percent pebbles and
10 percent cobbles; NaF pH 11.5; very strongly

acid; clear wavy boundary.

Bhs2-7 to 17 inches; yellowish red (5YR 4/6) extremely

gravelly silt loam, yellowish red (5YR 5/6) dry; dark

reddish brown (2.5YR 3/4) organic stains on faces of

peds, reddish brown (5YR 4/4) dry; moderate medium

subangular blocky structure; slightly hard, firm,

nonsticky and nonplastic; weakly smeary; few very fine

roots; common very fine irregular pores; about 50

percent pebbles and 10 percent cobbles; NaF pH 12.0;

very strongly acid; clear wavy boundary.

Bhs3-17 to 19 inches; dark brown (7.5YR 4/4) extremely

gravelly loam, strong brown (7.5YR 4/6) dry; massive;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; very few very fine roots; many fine irregular

pores; about 60 percent pebbles; NaF pH 12.0; very

strongly acid; abrupt wavy boundary.

2Cd-19 to 60 inches; light yellowish brown (2.5Y 6/4),

dense compact glacial till that breaks to very gravelly

loam, light gray (2.5Y 7/2) dry; massive; extremely

hard, very firm, nonsticky and nonplastic; weakly

smeary; about 40 percent pebbles; NaF pH 10.5; very

strongly acid.

The depth to dense, compact glacial till ranges from 14

to 20 inches. The content of rock fragments in the control

section ranges from 40 to 60 percent, which includes 5 to

10 percent cobbles.

The E horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs horizon has hue of 5YR or 7.5YR, value of 3

to 5 when moist and 4 to 6 when dry, and chroma of 4 to

6 when moist and 6 to 8 when dry. It is very gravelly loam

or very gravelly silt loam.

The 2Cd horizon is dense, compact glacial till. It has hue

of 2.5Y or 5Y, value of 4 to 6 when moist and 4 to 7 when

dry, and chroma of 2 to 4 when moist and 1 to 4 when dry.

It is dense glacial till that breaks to very gravelly loam, very

gravelly sandy loam, or very gravelly loamy sand.

Edmonds Series

The Edmonds series consists of very deep, somewhat

poorly drained soils formed in an admixture of loess and

volcanic ash over glacial outwash. These soils are on

outwash terraces and outwash plains. Slopes are 0 to 2

percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are coarse-loamy over sandy or sandy

skeletal, mixed, mesic, ortstein Typic Sideraquods.

Typical pedon of Edmonds loam, in an area of

Edmonds-Woodlyn loams, drained, 0 to 2 percent slopes;

3 miles north of Ferndale, 1,200 feet south and 1,900 feet

east of the northwest corner of sec. 8, T. 39 N., R. 2 E.

Ap1-0 to 6 inches; dark brown (7.5YR 3/2) loam, pinkish

gray (7.5YR 6/2) dry; weak fine granular structure; soft,

very friable, nonsticky and nonplastic; many very fine

and fine roots; many very fine irregular pores; NaF pH

9.9; moderately acid; clear smooth boundary.

Ap2-6 to 11 inches; dark brown (7.5YR 4/2) loam, pinkish

gray (7.5YR 7/2) dry; weak fine granular structure;

slightly hard, friable, nonsticky and nonplastic; many

very fine and fine roots; many very fine irregular pores;

NaF pH 10.4; moderately acid; abrupt smooth

boundary.

E-11 to 18 inches; dark grayish brown (10YR 4/2) loam,

light gray (10YR 7/2) dry; moderate medium subangular

blocky structure; hard, firm, nonsticky and nonplastic;

many very fine roots; many very fine irregular pores;

NaF pH 11.0; moderately acid; abrupt smooth boundary.

2Bs-18 to 23 inches; dark brown (10YR 3/3) loamy sand,

pale brown (10YR 6/3) dry; many coarse prominent dark

yellowish brown (10YR 3/6) mottles, reddish yellow

(7.5YR 6/6) dry; weak medium subangular blocky

structure; slightly hard, friable, nonsticky and nonplastic;

few very fine roots; common very fine irregular pores;

NaF pH 11.1; moderately acid; abrupt smooth boundary.

2Bsm-23 to 37 inches; yellowish red (5YR 4/6 and 5/6)

loamy sand, reddish yellow (5YR 6/6 and 7.5YR 6/6)

dry; 75 percent ortstein concretions 2 to 6 inches in

diameter; many coarse prominent dark brown (10YR

4/3) mottles, very pale brown (10YR 7/3) dry; massive;

extremely hard ortstein and slightly hard matrix;

extremely firm ortstein and friable matrix; nonsticky and

nonplastic; few fine irregular pores in matrix; NaF pH

10.7; moderately acid; abrupt smooth boundary.

2C-37 to 60 inches; sand that is dominantly dark grayish

brown (2.5Y 4/2) but is variegated; light brownish gray

(2.5Y 6/2) dry; single grain; loose; many fine irregular

pores; about 5 percent pebbles; NaF pH 9.9; slightly

acid.

The thickness of the solum is 20 to 40 inches. The

thickness of the loamy part of the solum is 14 to 20

inches. The particle-size control section is 0 to 5 percent

pebbles by weighted average.

The Ap horizon has hue of 7.5YR or 10YR, value of
3 or 4 when moist and 6 or 7 when dry, and chroma of 1

to 3 when moist and dry. Reaction is strongly acid or

moderately acid. Pedons in uncultivated areas have an A

horizon. This horizon is 3 to 7 inches thick and is similar to

the Ap horizon.

The E horizon has hue of 7.5YR or 10YR, value of 3 to 5

when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry. It is loam or sandy loam.

The 213s horizon has hue of 7.5YR or 10YR in the matrix

and 5YR or 7.5YR in the ortstein or mottles. It has value of

3 to 5 when moist and 5 to 7 when dry. It has chroma of 2

to 4 when moist and dry in the matrix and 4 to 6 in the

ortstein or mottles. It is loamy sand or sand. It has a

subhorizon that is 50 to 80 percent ortstein occurring as

rounded or angular concretions, slaglike fragments, or

irregularly shaped indurated accretions. This horizon is at

least 5 inches thick.

The 2C horizon has hue of 10YR, 2.5Y, or 5Y, value of 3

or 4 when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry. It is coarse sand or sand.

Eliza Series

The Eliza series consists of very deep, very poorly

drained soils formed in alluvium. These soils are on flood

plains, deltas, and tidal flats. Slopes are 0 to 1 percent.

The average annual precipitation is about 30 to 40 inches,

and the mean annual air temperature is about 50 degrees

F.

These soils are coarse-loamy, mixed, acid, mesic

Sulfic Fluvaquents.

Typical pedon of Eliza silt loam, drained, 0 to 1 percent

slopes, 3 miles southwest of Ferndale, 1,200 feet north

and 1,200 feet east of the southwest corner of sec. 6, T.

38 N., R. 2 E.

Ap-0 to 11 inches; very dark grayish brown (10YR 3/2)

and dark grayish brown (10YR 4/2) silt loam, light

brownish gray (2.5Y 6/2) and light gray (10YR 7/2)

dry; moderate medium granular structure; very hard,

friable, slightly sticky and plastic; many very fine and

fine roots; many very fine irregular pores; moderately

acid when moist and strongly acid when dry; abrupt

smooth boundary.

Cg1-11 to 15 inches; very dark grayish brown (10YR 3/2)

and dark grayish brown (10YR 4/2) silt loam, light

brownish gray (10YR 6/2) and light gray (2.5Y 7/2) dry;

common medium prominent yellowish brown (10YR 5/6)

mottles, brownish yellow (10YR 6/6) dry; massive; very

hard, friable, slightly sticky and plastic; many very fine

and fine irregular pores; strongly acid when moist and

very strongly acid when dry; abrupt smooth boundary.

Cg2-15 to 19 inches; gray (5Y 5/1) fine sandy loam,

light gray (5Y 6/1) dry; many coarse prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; slightly hard, very friable,

nonsticky and nonplastic; common very fine and fine

and few medium roots; many very fine irregular pores;

very strongly acid when moist and dry; abrupt smooth

boundary.

Cg3-19 to 24 inches; dark gray (N 4/0) fine sandy loam,

gray (N 6/0) dry; many medium prominent dark

yellowish brown (10YR 4/6) mottles, yellowish brown

(10YR 5/6) dry; massive; soft, very friable, nonsticky

and slightly plastic; common very fine and fine and few

medium roots; many very fine irregular pores; very

strongly acid when moist and dry; clear smooth

boundary.

Cg4-24 to 34 inches; stratified dark gray (5Y 4/1) silt

loam, gray (N 5/0) fine sandy loam, and strong brown

(7.5YR 5/8) sand, gray (N 5/0), light gray (N 6/0), and

strong brown (7.5YR 5/8) dry; massive in silt loam

and fine sandy loam and single grain in sand; soft,

very friable, nonsticky and nonplastic; few very fine

and fine roots; many very fine and common fine

irregular pores; very strongly acid when moist and

extremely acid when dry; clear smooth boundary.

Cg5-34 to 44 inches; stratified dark grayish brown (2.5Y

4/2) silt loam, dark gray (5Y 4/1) fine sandy loam, and

yellowish brown (10YR 5/6) sand, light brownish gray

(2.5Y 6/2), light gray (N 7/0), and brownish yellow

(10YR 6/6) dry; massive in silt loam and fine sandy

loam and single grain in sand; soft, very friable,

nonsticky and nonplastic; very few very fine roots; very

strongly acid when moist and extremely acid when dry;

abrupt smooth boundary.

Cg6-44 to 52 inches; stratified dark gray (5Y 4/1) silt

loam and fine sandy loam and dark yellowish brown

(10YR 4/6) sand, light gray (N 6/0 and N 7/0) and

yellowish brown (10YR 5/6) dry; massive in silt loam

and fine sandy loam and single grain in sand; soft, very

friable, nonsticky and nonplastic very strongly acid

when moist and extremely acid when dry; abrupt

smooth boundary.

Cg7-52 to 60 inches; stratified dark gray (N 4/0) silt loam

and fine sandy loam and yellowish brown (10YR 5/8)

sand, gray (N 5/0 and N 6/0) and brownish yellow

(10YR 6/8) dry; massive in silt loam and fine sandy

loam and single grain in sand; soft, very friable,

nonsticky and nonplastic; neutral when moist and

strongly acid when dry.

The 10- to 40-inch particle-size control section ranges

from 10 to 18 percent clay. These soils have an irregular

distribution of organic matter with increasing depth.
reduce the degree of soil compaction and displacement. In

areas where the soils have a high content of phyllite,

greater care is needed in the design and construction of

roads and in the selection of harvesting equipment.

Many of the wood products produced in the survey area

are transported to processing facilities outside of the area.

Much of the wood for pulp is used locally at a large pulp

and paper mill. Other processors in the area include a few

shake and shingle mills, one plywood and veneer mill, four

softwood lumber mills, and one outlet for posts, poles, and

pilings. Red alder wood products are generally transported

out of the survey area for processing.

A demand for urban and industrial development sites

exists in the survey area. Total commercial woodland

acreage may decline in the area as pressure to convert to

other uses increases, but loss of productive acres may be

partially offset by intensive management practices.

A statistical analysis was used in obtaining the woodland

site data in this survey. Data from forest tree sites were

taken by a forester. When a prospective tree stand on a

particular map unit was identified by the forester, five site

trees, generally the dominant trees on the site, were

selected. Tree height, diameter at breast height, and breastheight age were determined. All ground vegetation also was

identified and recorded on a data card (39).

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

index for the five trees was calculated by adjusting the

breast-height age to total age for Douglas fir (28) and

western hemlock (4). On the basis of a 50-year site curve,

the mean site index was calculated directly from average

breast-height age and total tree height for Douglas fir (22)

and western hemlock (47). The site index for red alder was

calculated in the same manner using average age at

breast-height and total height (49). A statistical analysis of

all site indices for each soil series or map unit was

conducted. Standard deviation, standard error of the mean,

and coefficient of variation were calculated (38).

All of the site data for a particular series was analyzed

initially to obtain a coefficient of variation of less than 8

percent. If the 8 percent threshold was exceeded, then the

site data applicable to each map unit within the series was

analyzed in the same manner. If a 5 foot or more difference

in site indices existed between map units, then those

calculated site indices were used. If the difference was less

than 5 feet and the coefficient of variation was less than 8

percent, the site indices were averaged for the series. For

series without adequate site data, an estimated site index

was established using data gathered for similar soils (45).

Soil surveys are becoming increasingly more

important to forest managers as they seek ways of

increasing the productivity of their forested lands. Plants

respond better to applications of fertilizers on some soils

than on others. Some soils are more susceptible to

landslides and erosion after road building and harvesting,

and others require special effort to harvest and reforest.

Each description of the map units suitable for producing

wood crops includes information about forest productivity,

timber production, limitations affecting timber harvesting,

and common forest understory plants. The methods and

procedures used to develop the information for the map

units are described in the National Forestry Manual (45) and

the Forest Land Grading Procedures Handbook (39).

Table 8 summarizes forestry information given in the map

unit descriptions and can serve as a quick reference for

important forestry interpretations. Map unit symbols are

listed, and the ordination (woodland suitability) symbol for

each map unit in the table is given. All soils having the

same ordination symbol require the same general kinds of

forest management and have about the same potential

productivity.

The ordination symbol is based on a uniform system that

indicates the potential productivity of an individual soil and

the principal hazards or limitations of that soil. The first

element of the ordination symbol is a number that denotes

the potential productivity in terms of cubic meters of wood

per hectare per year for the indicator tree species. The

potential productivity is based on the site index and the

corresponding culmination of the mean annual increment.

For example, the number 1 indicates a potential

production of 1 cubic meter of wood per hectare (14.3

cubic feet per acre) per year and 10 indicates a potential

production of 10 cubic meters of wood per hectare (143

cubic feet per acre) per year.

The second element of the symbol, a letter, indicates the

major kind of soil characteristic that limits tree growth or

management. The letter X indicates stoniness or rockiness;

W, excessive water, either seasonally or year round, in or

on the soil; T toxic substances within the root zone; D,

restricted rooting depth; C, clayey soils; S, sandy soils; F,

fragmented or skeletal soils with coarse fragments that are

more than 2 millimeters and less than 10 inches in size;

and R, relief or slope. The letter A indicates no or only

slight limitations affect use and management. If a soil has

more than one limitation, the letter denoting the most

limiting characteristic is used.

The number designation of the ordination symbol also

represents the productivity class. Productivity class is

calculated for other important common trees on the soil for

which a site index has been provided. This
figure denotes potential productivity in terms of cubic

meters of wood per hectare per year.

In table 8 the soils also are rated for a number of

factors to be considered in management. Ratings of

slight, moderate, and severe are used to indicate the

degree of major soil limitations. For each moderate or

severe rating, a sentence in the applicable map unit

description explains the soil factor or factors that are the

basis of that rating.

Ratings of erosion hazard indicate the probability that

damage will occur as a result` of site preparation and

cutting where the soil is exposed along roads, skid trails,

fire lanes, and log-handling areas. Forests that have been

burned or overgrazed are also subject to erosion. Ratings

of the erosion hazard are based on the percent of the

slope. A rating of slight indicates that no particular

prevention measures are needed under ordinary

conditions. A rating of moderate indicates that erosioncontrol measures are needed in certain silvicultural

activities. A rating of severe indicates that special

precautions are needed to control erosion in most

silvicultural activities.

Ratings of the equipment limitation reflect the soil

characteristics and conditions that restrict the use of

equipment, either year round or seasonally. A rating of

slight indicates that the use of equipment is not normally

restricted 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 or management, or a hazard in the

use of equipment. Slope and wetness are the main factors

that cause equipment limitations. As slope gradient and

length increase, using wheeled equipment becomes more

difficult. On the steeper slopes, tracked equipment must be

used. On the steepest slopes, even tracked equipment

cannot be operated safely and more sophisticated systems

must be used. Wetness, especially in combination with fine

texture, can severely limit the use of equipment, making

harvesting practical only during dry summer months.

Ratings of seedling mortality indicate the probability of the

death of naturally occurring or planted tree seedlings as

influenced by kinds of soil or topographic conditions. Plant

competition is not considered in the ratings. The ratings

apply to healthy, dormant seedlings from good stock that

are properly planted or naturally established seedlings that

germinate during a period of insufficient soil moisture. A

rating of slight indicates that no significant mortality is

expected under usual conditions; moderate indicates that

some mortality can be expected and that extra precautions

are advisable; and severe indicates that mortality will be

high and

extra precautions are essential for successful

reforestation. Seedling mortality can be caused by

wetness; by droughtiness in the surface layer, especially

on south- or southwest-facing slopes; or by the position of

the soil on a ridgetop. To offset these, larger than usual

planting stock, special site preparation, a surface

drainage system, or reinforcement planting may be

needed.

Ratings of windthrow hazard are based on soil

characteristics that affect the development of tree roots and

the ability of the soil to hold trees firmly. A rating of slight

indicates that trees normally are not blown down by the

wind. Strong winds may break the trees but do not uproot

them. A rating of moderate indicates that an occasional tree

may be blown down during periods of excessive wetness

and moderate or strong winds, and a rating of severe

indicates that many trees are expected to be blown down

during these periods. A restricted rooting depth caused by

a high water table, underlying bedrock, and an impervious

layer or poor anchoring of roots because of a loose surface

layer and subsoil are responsible for windthrow. Moderate

and severe ratings indicate the need for more care in

thinning the edges of woodland stands, a plan calling for

periodic removal of windthrow trees, and an adequate road

and trail system to allow for this removal.

Ratings of plant competition indicate the likelihood of the

invasion or growth of undesirable brushy plants when

openings are made in the tree canopy. A rating of slight

indicates that unwanted brushy plants are not likely to

delay natural reforestation and that planted seedlings can

survive and grow well without undue competition; moderate

indicates that competition will delay natural or planted

reforestation; and severe indicates that competition can be

expected to prevent natural or planted reforestation.

Favorable climate and soil characteristics account for plant

competition. In many areas the key to predicting brush

competition is the quantity and proximity of seed sources of

undesirable plants or the quantity of unwanted bush

rootstocks that will resprout after harvest activities.

Moderate and severe ratings indicate the need for careful

and thorough cleanup after harvest in preparation for

reforestation and the possible need for mechanical or

chemical treatment to retard the growth of brush and allow

seedlings to become established.

The potential productivity of common trees on a soil is

expressed as a site index and a productivity class. The site

index is determined by measuring the height and age of

selected trees within stands of a given species (4, 22, 28,

47, 49). It applies to fully stocked, even-aged, unmanaged

stands. The greatest timber yields, usually expressed in

board feet or cubic feet per
acre, can be expected from map units with the highest site

index values. These values can be converted into

estimated yields at various ages by carefully using

appropriate yield publications (4, 9, 10, 28, 48, 49).

Common trees are listed in the same order as that of

their general occurrence observed on the map unit.

Generally, only one or two species will predominate.

Trees to plant are those that are planted for reforestation

or that, under suitable conditions, are allowed to regenerate

naturally. The species listed in table 8 are suited to the

soils and can be used for commercial wood production. The

desired product, the topographic position (such as a

ridgetop), and personal preference are three of many

factors that can influence the choice of suitable trees to

use for reforestation.

Windbreaks and Environmental Plantings

Dennis J. Robinson, area forester, Soil Conservation Service,

helped to prepare this section.

Windbreaks protect livestock, buildings, and yards from

wind and snow. They also protect fruit trees and gardens,

and they furnish habitat for wildlife. Several rows of lowand high-growing broadleaf and coniferous trees and

shrubs provide the most protection.

Most of the lowland soils in the survey area were

originally forested. A large portion of the native vegetation,

however, has been cleared for farms and towns. In the

north-central and northeast parts of the lowland area,

between the towns of Everson and Sumas, windbreaks

protect farm buildings and houses from northeast winds.

Weather systems moving southwest from the Fraser River

Valley of Canada bring snow and cold, desiccating winds

to the area. As a result, windbreaks are needed for

protection. Windbreaks and environmental plantings can be

established. Measures that maintain them are needed.

Plantings can include a single species or a variety of

species.

The most effective arrangement of windbreak plantings

consists of dense, low-growing shrubs in the windward

rows, taller deciduous trees or shrubs in the center row or

rows, and evergreen trees or shrubs on the leeward side

(44). Such an arrangement makes the windbreak more

effective in winter. If only one or two rows are planted,

species that provide maximum protection should be

selected. For example, if protection of a large area is

needed, tall trees should be planted, or if control of ground

winds is needed, dense shrubs or evergreens are most

effective. Generally, wind movement on the leeward side

of the planting is effectively reduced to a distance equal to

10 to 20 times the height of the windbreak.

Plants suitable for windbreaks and environmental

plantings in the survey area have not been tested. Many

windbreaks that are installed consist primarily of adapted

native species of deciduous trees and shrubs and

coniferous trees. Lombardy poplar is the most suitable

deciduous tree. Douglas fir, Rocky Mountain juniper,

western redcedar, ponderosa pine, and grand fir are the

most commonly used evergreen species. Native and

adapted shrub species, such as willows and common lilac,

are suitable for use in the low-growing shrub row in the

windbreak plantings. Generally, adequate moisture for

growth is provided by normal precipitation. Irrigation may

be necessary, however, on the drier sites in late August and

September.

The spacing between rows and between the trees and

shrubs in the rows is important. Deciduous trees should be

spaced at least 12 feet apart in the row, shrubs should be 3

or 4 feet apart, and evergreen trees should be at least 6

feet apart. The rows of trees should be 12 to 18 feet apart.

The size of the cultivating equipment is a consideration in

row-to-row spacing.

Other aspects of layout are equally important.

Farmstead windbreaks should be at least 100 feet from

the buildings so that air can move on hot days. Rounded

corners are easier to cultivate than square ones. Areas to

be planted should be free of vegetation before the trees or

shrubs are planted.

Environmental plantings help to beautify and screen

houses and other buildings and to abate noise. The

plants, mostly evergreen shrubs and trees, are closely

spaced. To ensure plant survival, a healthy planting stock

of suitable species should be planted properly on a well

prepared site and maintained in good condition.

Additional information on planning windbreaks and

screens and planting and caring for trees and shrubs

can be obtained from local offices of the Soil

Conservation Service or the Cooperative Extension

Service or from a local nursery.

Recreation

Whatcom County has many areas of scenic,

recreational, geologic, and historic interest. These areas

are used for camping, hiking, hunting, fishing, sightseeing,

mountain climbing, bicycling, picnicking, and boating.

Public areas available for recreation within the survey area

include eight county parks, three state parks, a state game

range, and several fish hatcheries.

Important marine features include Lummi and Eliza

Islands, Point Francis, Bellingham Bay, numerous beaches,

and scenic Chuckanut Drive, which follows the water's

edge south of Bellingham. The western boundary of Mount

Baker National Forest is the eastern boundary of the

survey area. Lake Whatcom, Lake Samish, the Nooksack

River, and the Strait of Georgia
are prime fishing areas. Mount Baker and Twin Sisters

Mountain, immediately east of the survey area, are

important recreational areas.

The soils of the survey area are rated in table 9

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 sewer lines. 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 9, 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 9 can be supplemented by

other information in this survey, for example,

interpretations for septic tank absorption fields in table 12

and interpretations for dwellings without basements and

for local roads and streets in table 11.

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 and horseback riding 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

The survey area contains a wide variety of habitat types

ranging from salt water to alpine mountain peaks, which

support a variety of wildlife. Approximately three-fourths of

the survey area on the western slope of the Cascade

Range is covered by coniferous forests. Numerous rocky

peaks, which are above 8,000 feet, provide a home for

species characteristic of these alpine environments. These

species include pika, white-tailed ptarmigan, and mountain

goat.

The western one-fourth of the survey area consists of

lowlands and relatively flat terrain, which is used mainly for

agriculture. Agricultural land is interspersed with numerous

remnant patches of coniferous forest and riparian

woodland. These small wooded areas support woodland

wildlife and provide cover for openland wildlife. The

lowlands contain numerous wetlands, sloughs, and creeks,

which provide important habitat for fish, waterfowl, and

other aquatic and wetland wildlife.

Much of the survey area is drained by the Nooksack

River, which flows into Bellingham Bay. About 650 rivers

and streams are in the Nooksack drainage system, which

includes about 1,300 miles of streams and tributaries. Bald

eagles concentrate along the river in winter to feed on the

salmon, steelhead, and cutthroat trout that migrate

upstream each year. In an average year, about 55,000

adult salmon return to spawn in the Nooksack drainage

system.

Bellingham, Lummi, Chuckanut, and Birch Bays

provide habitat for saltwater fish and shellfish. An
abundance of marine invertebrates and aquatic

vegetation attract large resident and wintering

populations of loons, grebes, cormorants, herons,

ducks, shorebirds, gulls, ferns, and black brants.

Soils and climate 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 10, 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, trillium,

bedstraw, and fireweed.

Hardwood trees and woody understory produce nuts or

other fruit, buds, catkins, twigs, bark, and foliage. Soil

properties and features that affect the growth of hardwood

trees and shrubs are depth of the root zone, available

water capacity, and wetness. Examples of these plants

are red alder, bigleaf maple, Pacific dogwood,

cottonwood, vine maple, and willow. Examples of fruitproducing trees and shrubs that are suitable for planting

on soils rated good are blackberry, apple, cherry,

crabapple, and mountain ash.

Coniferous plants furnish browse and seeds. 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 Douglas fir, western hemlock, noble

fir, and western redcedar.

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,

Oregongrape, and salmonberry.

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. Wildlife attracted to these areas

include California quail, pheasant, mourning dove,

meadowlark, chipping sparrow, and brush rabbit.

Habitat for woodland wildlife consists of areas of

deciduous and coniferous plants and associated grasses,

legumes, and wild herbaceous plants. Wildlife attracted to

these areas include blue and ruffed grouse, thrushes,

woodpeckers, squirrels, Cascade red fox, mountain goat,

ptarmigan, black-tailed 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, herons, 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 or 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 evaluate the potential of

areas for residential, commercial, industrial, and recreation

uses; make preliminary estimates of construction

conditions; evaluate alternative routes for roads, streets,

highways, pipelines, and underground cables; evaluate

alternative sites for sanitary landfills, septic tank absorption

fields, and sewage lagoons; plan detailed onsite

investigations of soils and geology; locate potential sources

of gravel, sand, earthfill, and topsoil; plan drainage

systems, irrigation systems, ponds, terraces, and other

structures for soil and water conservation; and 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 11 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 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, slope, and

flooding affect the ease of excavation and construction.

Landscaping and grading that require cuts and fills of more

than 5 or 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), shrink-swell potential, frost action

potential, and depth to a high water table affect the trafficsupporting 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 12 shows the degree and 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 12 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 filter the effluent effectively. 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 12 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 groundwater pollution. Ease of excavation and revegetation

needs to be considered.

The ratings in table 12 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 wind erosion.

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 13 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 to 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, a 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 a 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 depth to the water table is

less than 1 foot. These soils 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 13, 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 14 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

and for embankments, dikes, and levees. 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, terraces and

diversions, and grassed waterways.

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.

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 control 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.

Grassed waterways are natural or constructed channels,

generally broad and shallow, that conduct surface water to

outlets at a nonerosive velocity. Large stones, wetness,

slope, and depth to bedrock or to a cemented pan affect

the construction of grassed waterways. A hazard of wind

erosion, low available water capacity, restricted rooting

depth, toxic substances such as salts or sodium, and

restricted permeability adversely affect the growth and

maintenance of the grass after construction.
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 classification, 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 15 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 the content of particles coarser than sand

is as much as 15 percent, 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). Both systems are described in

the PCA Soil Primer (33).

The Unified system classifies soils according to

properties that affect their use as construction material.

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, CL-ML.

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 grainsize 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 A8 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 ovendry 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 generally 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 16 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 earthmoving operations.

Moist bulk density is the weight of soil (ovendry) per unit

volume. Volume is measured when the soil is at field

moisture capacity, that is, the moisture content at 1/3 bar

moisture tension. Weight is determined after drying the soil

at 105 degrees C. In this table, the estimated moist bulk

density of each major soil horizon is expressed in grams

per cubic centimeter of soil material that is less than 2

millimeters in diameter. Bulk density data are used to

compute shrink-swell potential, available water capacity,

total pore space, and other soil properties. The moist bulk

density of a soil indicates the pore space available for

water and roots. A bulk density of more than 1.6 can

restrict water storage and root penetration. Moist bulk

density is influenced by texture, kind of clay, content of

organic matter, and soil structure.

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.

Salinity is a measure of soluble salts in the soil at

saturation. It is expressed as the electrical conductivity of

the saturation extract, in millimhos per centimeter at 25

degrees C. Estimates are based on field and laboratory

measurements at representative sites of nonirrigated soils.

The salinity of irrigated soils is affected by the quality of the

irrigation water and by the frequency of water application.

Hence, the salinity of soils in individual fields can differ

greatly from the value given in the table. Salinity affects the

suitability of a soil for crop production, the stability of soil if

used as construction material, and the potential of the soil

to corrode metal and concrete.

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.

Wind erodibility groups are made up of soils that have

similar properties affecting their resistance to wind erosion

in cultivated areas. The groups indicate the susceptibility of

soil to wind erosion. Soils are grouped according to the

following distinctions:

1. Coarse sands, sands, fine sands, and very fine

sands. These soils are generally not suitable for crops.

They are extremely erodible, and vegetation is difficult to

establish.

2. Loamy coarse sands, loamy sands, loamy fine sands,

loamy very fine sands, and sapric soil material. These soils

are very highly erodible. Crops can be grown if intensive

measures to control wind erosion are used.

3. Coarse sandy loams, sandy loams, fine sandy

loams, and very fine sandy loams. These soils are highly

erodible. Crops can be grown if intensive measures to

control wind erosion are used.

4L. Calcareous loams, silt loams, clay loams, and silty

clay loams. These soils are erodible. Crops can be grown if

intensive measures to control wind erosion are used.

4. Clays, silty clays, noncalcareous clay loams, and silty

clay loams that are more than 35 percent clay. These soils

are moderately erodible. Crops can be grown if measures to

control wind erosion are used.

5. Noncalcareous loams and silt loams that are less

than 20 percent clay and sandy clay loams, sandy clays,

and hemic soil material. These soils are slightly erodible.

Crops can be grown if measures to control wind erosion are

used.

6. Noncalcareous loams and silt loams that are

more than 20 percent clay and noncalcareous clay

loams that are less than 35 percent clay. These soils are

very slightly erodible. Crops can be grown if ordinary

measures to control wind erosion are used.

7. Silts, noncalcareous silty clay loams that are less than

35 percent clay, and fibric soil material. These soils are

very slightly erodible. Crops can be grown if ordinary

measures to control wind erosion are used.

8. Soils that are not subject to wind erosion because of

coarse fragments on the surface or because of surface

wetness.

Organic matter is the plant and animal residue in the soil

at various stages of decomposition. In table 16, the

estimated content of organic matter is expressed as a

percentage, by weight, of the soil material that is less than

2 millimeters in diameter.

The content of organic matter in 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 17 and 18 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 infiltration 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 is not considered flooding, nor is water in

swamps and marshes.

Table 17 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,

occasional, and frequent. None means that flooding is not

probable; rare that it is unlikely but possible under unusual

weather conditions; occasional that it occurs, on the

average, once or less in 2 years; and frequent that it

occurs, on the average, more than once in 2 years.

Duration is expressed as brief if less than 7 days, long if 7

days to 1 month, and very long if more than 1 month.

Probable dates are expressed in months.

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 17 are the depth to the seasonal high water table;

the kind of water table-that is, perched 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 17.

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. 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 in table 18 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 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 excavation.

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.

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 18 shows the expected initial subsidence,

which usually is a result of drainage, and total 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 the 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.
Soils in Whatcom County that are below an elevation of

approximately 800 feet are not usually subject to potential

frost action.

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 (43). 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.

Table 19 shows the classification of the soils in the survey

area. The categories are defined in the following

paragraphs.

ORDER. Eleven 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 Spodosol.

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 Orthod (Orth, meaning true, plus od,

from Spodosol).

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 Haplorthods (Hapl, meaning minimal

horizonation, plus orthod, a suborder of Spodosols).

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 Aqualfic identifies the subgroup that is

saturated with water at some time of the year and has an

argillic horizon. An example is Aqualfic Haplorthods.

FAMILY. Families are established within a subgroup on

the basis of physical and chemical properties and other

characteristics that affect management. Generally, 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-loamy, mixed, mesic Aqualfic Haplorthods.

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. 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 (41). Many, of the technical terms used in the

descriptions are defined in Soil Taxonomy (43). 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."

Barneston Series

The Barneston series consists of very deep, somewhat

excessively drained soils formed in a mixture of volcanic

ash and loess, over, glacial outwash. These
soils are on outwash terraces and terrace escarpments.

Slopes are 0 to 60 percent. The average annual

precipitation is 60 to 75 inches, and the mean annual air

temperature is about 47 degrees F.

These soils are sandy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Barneston gravelly loam, 0 to 8

percent slopes, 1 mile southeast of Kendall, 2,000 feet

north and 1,250 feet west of the southeast corner of sec.

35, T. 40 N., R. 5 E.

Oi-2.5 to 2 inches; undecomposed needles, leaves,

and twigs.

Oa-2 inches to 0; decomposed organic mat; many fine

and medium roots.

E-0 to 1.5 inches; brown (7.5YR 5/2) gravelly loam,

pinkish gray (7.5YR 6/2) dry; weak fine and medium

subangular blocky structure; slightly hard, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine, fine, and medium roots; many fine irregular pores;

about 20 percent pebbles; NaF pH 9.4; strongly acid;

clear smooth boundary.

Bs1-1.5 to 8 inches; dark brown (7.5YR 3/4) gravelly

loam, brown (7.5YR 5/4) dry; weak fine and medium

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many very fine, fine,

and medium roots; many fine irregular pores; about 30

percent pebbles; NaF pH 11.0; strongly acid; clear

wavy boundary.

Bs2-8 to 14 inches; dark brown (7.5YR 3/4) very gravelly

loam, light brown (7.5YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; common very fine and many

fine roots;. many fine irregular pores; about 45 percent

pebbles; NaF pH 11.5; strongly acid; clear wavy

boundary.

2C1-14 to 28 inches; dark yellowish brown (10YR 4/4)

extremely gravelly sand, light yellowish brown (10YR

6/4) dry; single grain; loose; many fine and few medium

roots; many medium and coarse irregular pores; about

70 percent pebbles and 5 percent cobbles; NaF pH

11.5; strongly acid; clear smooth boundary.

2C2-28 to 40 inches; olive brown (2.5Y 4/4) extremely

gravelly sand, light yellowish brown (2.5Y 6/4) dry;

single grain; loose; common fine and few medium roots;

many medium and coarse subangular pores; about 75

percent pebbles and 5 percent cobbles; moderately

acid; clear smooth boundary.

2C3-40 to 60 inches; dark grayish brown (2.5Y 4/2)

extremely gravelly sand, light brownish gray (2.5Y 6/2)

dry; single grain; loose; few medium roots; many

medium and coarse irregular pores; about 70

percent pebbles and 5 percent cobbles; moderately

acid.

The thickness of the solum and of the part of the profile

influenced by volcanic ash is 13 to 24 inches. The content

of clay in the lower part of the particle-size control section

is 0 to 3 percent. By weighted average, the upper part of

the control section has 35 to 60 percent pebbles and 0 to

10 percent cobbles and the lower part has 45 to 70

percent pebbles, 5 to 15 percent cobbles, and 0 to 15

percent stones.

The E horizon has hue of 7.5YR or 10YR, value of 2 to 5

when moist and 4 to 7 when dry, and chroma of 2 to 4

when moist and dry. Some pedons have an A horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3

to 5 when moist and 5 or 6 when dry, and chroma of 4 to

6 when moist and dry. It is gravelly loam, gravelly sandy

loam, very gravelly loam, or very gravelly sandy loam.

The 2C horizon has hue of 10YR or 2.5Y, value of 4 or

5 when moist and 6 or 7 when dry, and chroma of 2 to 6

when moist and dry. It is very gravelly loamy sand, very

gravelly sand, extremely gravelly loamy sand, or extremely

gravelly sand.

Barnhardt Series

The Barnhardt series consists of very deep, well

drained soils formed in a mixture of volcanic ash, loess,

and glacial outwash. These soils are on terraces. Slopes

are 0 to 5 percent. The average annual precipitation is

about 35 to 50 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are loamy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Barnhardt gravelly loam, 0 to 5

percent slopes, about 2 miles southwest of Everson,

250 feet south and 1,900 feet west of the northeast

corner of sec. 11, T. 39 N., R. 3 E.

Oi-1 inch to 0; undecomposed needles, leaves, and

twigs.

A-0 to 3 inches; dark brown (7.5YR 3/2) gravelly loam,

brown (10YR 5/3) dry; weak fine granular structure;

soft, very friable, nonsticky and nonplastic; weakly

smeary; many very fine and common fine roots; many

very fine irregular pores; about 20 percent

pebbles; NaF pH 10.0; slightly acid; clear wavy

boundary.

Bs1-3 to 9 inches; dark brown (7.5YR 4/4) gravelly

loam, light yellowish brown (10YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many
very fine and common fine roots; many very fine

irregular pores; about 25 percent pebbles; NaF pH

10.5; moderately acid; clear wavy boundary.

Bs2-9 to 21 inches; yellowish brown (10YR 5/4) extremely

gravelly loam, very pale brown (10YR 7/4) dry; weak fine

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many very fine,

common fine, and few medium roots; many very fine

irregular pores; about 60 percent pebbles; NaF pH

10.5; moderately acid; gradual wavy boundary.

BC-21 to 42 inches; yellowish brown (10YR 5/4) extremely

gravelly sandy loam, pale yellow (2.5Y 7/4) dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common very

fine, fine, medium, and coarse roots; many very fine

irregular pores; about 75 percent pebbles; NaF pH

10.5; moderately acid; gradual wavy boundary.

C-42 to 60 inches; yellowish brown (10YR 5/4) extremely

gravelly loam, very pale brown (10YR 7/4) dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; few very fine

roots; many very fine irregular pores; about 70 percent

pebbles; NaF pH 9.6; moderately acid.

The part of the profile influenced by volcanic ash is 60 or

more inches thick. The thickness of the solum is 8 to 30

inches. The particle-size control section has 50 to 75

percent pebbles and 0 to 5 percent cobbles by weighted

average.

The A horizon has hue of 7.5YR or 10YR, value of 3 or 4

when moist, and chroma of 2 to 4 when moist and dry.

The Bs horizon has hue of 7.5YR or 10YR and value of 4

or 5 when moist and 6 or 7 when dry. It is gravelly loam,

very gravelly loam, very gravelly silt loam, or extremely

gravelly loam.

The BC and C horizons have 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 and dry. Within the particle-size control

section, they are very gravelly loam, extremely gravelly

sandy loam, or very gravelly silt loam. Below the control

section, they are extremely gravelly loam, extremely

gravelly sandy loam, or extremely gravelly loamy sand.

Bellingham Series

The Bellingham series consists of very deep, poorly

drained soils formed in an admixture of loess, alluvium,

and lacustrine deposits. These soils are in depressions on

terraces. Slopes are 0 to 2 percent. The average

annual precipitation is 35 to 50 inches, and the mean

annual air temperature is about 50 degrees F.

These soils are fine, mixed, nonacid, mesic Mollic

Haplaquepts.

Typical pedon of Bellingham silty clay loam, 0 to 2

percent slopes, 1.5 miles north of Everson, 2,200 feet

south and 100 feet east of the northwest corner of sec. 19,

T. 40 N., R. 4 E.

Ap-0 to 10 inches; very dark grayish brown (10YR 3/2) silty

clay loam, brown (10YR 5/3) dry; moderate fine

subangular blocky structure; slightly hard, friable,

slightly sticky and plastic; many very fine and fine

roots; many very fine irregular pores; slightly acid; clear

smooth boundary.

Bg1-10 to 18 inches; very dark grayish brown (10YR 3/2)

and dark brown (10YR 4/3) silty clay loam, grayish

brown (10YR 5/2) and pale brown (10YR 6/3) dry;

common fine prominent mottles, yellowish brown

(10YR 5/6) moist and dry; moderate fine subangular

blocky structure; slightly hard, firm, slightly sticky and

plastic; common very fine and few fine roots; many

very fine irregular pores; few patchy clay films on

faces of peds; slightly acid; abrupt smooth boundary.

Bg2-18 to 24 inches; dark grayish brown (2.5Y 4/2) and

olive brown (2.5Y 4/4) silty clay loam, light gray (2.5Y

7/2) and pale yellow (2.5Y 7/4) dry; common medium

prominent yellowish brown (10YR 5/6) mottles, brownish

yellow (10YR 6/6) dry; weak coarse prismatic structure

parting to medium fine subangular blocky; very hard,

firm, slightly sticky and plastic; common very fine roots;

many very fine irregular pores; neutral; clear smooth

boundary.

CB-24 to 30 inches; grayish brown (2.5Y 5/2) silty clay

loam, light gray (2.5Y 7/2) dry; many medium distinct

light olive brown (2.5Y 5/4) mottles, light yellowish

brown (2.5Y 6/4) dry; moderate medium subangular

blocky structure; very hard, firm, slightly sticky and

plastic; few very fine roots; common very fine irregular

pores; few patchy clay films on faces of peds; neutral;

clear smooth boundary.

C1-30 to 38 inches; grayish brown (2.5Y 5/2) silty clay

loam, light gray (5Y 7/1) dry; common fine prominent

light olive brown (2.5Y 5/4) mottles, light yellowish

brown (2.5Y 6/4) dry; moderate coarse prismatic

structure parting to moderate medium subangular

blocky; very hard, firm, slightly sticky and plastic; few

very fine roots; neutral; clear smooth boundary.

C2-38 to 60 inches; grayish brown (2.5Y 5/2) silty clay

loam, white (2.5Y 8/2) dry; common fine prominent

light olive brown (2.5Y 5/4) mottles, light yellowish

brown (2.5Y 6/4) dry; moderate coarse prismatic
structure parting to moderate medium subangular

blocky; very hard, firm, slightly sticky and plastic; few

very fine roots; neutral.

The particle-size control section has 35 to 60 percent

clay by weighted average. The thickness of the solum is 10

to 30 inches.

The Ap horizon has value of 2 or 3 when moist and 4 or

5 when dry and chroma of 1 to 3 when moist and dry.

The Bg horizon has hue of 10YR, 2.5Y, or 5Y, value of 3

to 6 when moist and 5 to 8 when dry, and chroma of 1 to 3

when moist and dry. It is silty clay loam or silty clay.

The C horizon has hue of 2.5Y or 5Y, value of 5 or 6

when moist and 7 or 8 when dry, and chroma of 1 or 2

when moist and dry. It is dominantly silty clay loam, silty

clay, or clay. In some pedons, however, it has thin strata of

silt loam or sandy loam.

The Bellingham soils in this survey area are

taxadjuncts to the series because they have a mollic

epipedon. This difference, however, does not

significantly affect the use and management of the soils.

Birchbay Series

The Birchbay series consists of very deep, moderately

well drained soils formed in an admixture of loess and

volcanic ash over glaciofluvial deposits and glaciomarine

drift. These soils are on wave-reworked glaciomarine drift

plains. Slopes are 0 to 15 percent. The average annual

precipitation is 30 to 40 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are coarse-loamy over sandy or sandyskeletal, mixed, mesic Typic Haplorthods.

Typical pedon of Birchbay silt loam, 0 to 3 percent

slopes, 5 miles west of Ferndale, 2,400 feet south and

1,600 feet east of the northwest corner of sec. 16, T. 39

N., R. 1 E.

Ap-0 to 8 inches; dark brown (10YR 3/3) silt loam, dark

yellowish brown (10YR 4/4) dry; moderate medium

granular structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; many very fine and fine

roots; many very fine irregular pores; about 2 percent

pebbles; NaF pH 9.8; slightly acid; abrupt smooth

boundary.

Bs1-8 to 12 inches; dark brown (7.5YR 4/4) silt loam,

strong brown (7.5YR 5/6) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; common very fine and fine

roots; many very fine irregular pores; about 10

percent pebbles; NaF pH 10.5; moderately acid;

clear smooth boundary.

Bs2-12 to 24 inches; dark yellowish brown (10YR 4/4)

gravelly silt loam, brownish yellow (10YR 6/6) dry;

weak medium subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine roots; many very fine

irregular pores; about 20 percent pebbles; NaF pH

11.0; moderately acid; clear smooth boundary.

2C1-24 to 42 inches; dark yellowish brown (10YR 4/4)

very gravelly sand, brownish yellow (10YR 6/6) dry;

massive; slightly hard, very friable, nonsticky and

nonplastic; very few fine roots; many fine irregular

pores; about 35 percent pebbles and 5 percent

cobbles; NaF pH 11.0; moderately acid; clear wavy

boundary.

3C2-42 to 60 inches; light olive brown (2.5Y 5/4) loam,

pale yellow (2.5Y 7/4) dry; many large prominent strong

brown (7.5YR 5/6) mottles, reddish yellow (7.5YR 6/6)

dry; massive; very hard, firm, slightly sticky and slightly

plastic; few fine irregular pores; about 10 percent

pebbles; moderately acid.

The thickness of the part of the profile influenced by

volcanic ash and the depth to the 2C horizon are 14 to 32

inches. Depth to the 3C horizon is 40 to 60 inches.

The A horizon has hue of 7.5YR or 10YR, value of 2 to 4

when moist and 4 or 5 when dry, and chroma of 2 to 4

when moist and 3 or 4 when dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 or 6 when dry, and chroma of 4 to 6

when moist and dry. It is silt loam, loam, gravelly silt loam,

or gravelly loam.

The 2C horizon has hue of 10YR or 2.5Y, value of 3 to 5

when moist and 5 or 6 when dry, and chroma of 2 to 4

when moist and 2 to 6 when dry. It is very gravelly loamy

sand or very gravelly sand.

The 3C horizon has hue of 10YR to 5Y, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. It is dominantly loam, gravelly loam,

clay loam, gravelly clay loam, or silty clay loam. In some

pedons, however, it has thin strata of sandy loam.

Blainegate Series

The Blainegate series consists of very deep, poorly

drained soils formed in marine deposits. These soils are on

marine terraces. Slopes are 0 to 1 percent. The average

annual precipitation is 30 to 40 inches, and the mean

annual air temperature is about 50 degrees F.

These soils are very fine, mixed, mesic Typic

Argiaquolls.
Typical pedon of Blainegate silty clay, 0 to 1 percent

slopes, 1 mile east of Blaine, 2,600 feet south and 1,800

feet east of the northwest corner of sec. 5, T. 40 N., R. 1

E.

Ap-0 to 9 inches; very dark grayish brown (10YR 3/2) silty

clay, grayish brown (10YR 5/2) dry; few fine prominent

yellowish brown (10YR 5/8) mottles, brownish yellow

(10YR 6/8) dry; moderate medium granular structure;

slightly hard, friable, slightly sticky and plastic; many

very fine and common fine roots; many very fine

irregular pores; moderately acid; abrupt smooth

boundary.

Btg-9 to 27 inches; dark gray (5Y 4/1) clay, light gray (5Y

7/1) dry; many fine prominent yellowish brown (10YR

5/6) mottles, brownish yellow (10YR 6/6) dry; massive;

slightly hard, friable, sticky and plastic; many very fine

and common fine roots; many very fine irregular and

common very fine tubular pores; few patchy clay films

on faces of peds; slightly acid; clear smooth boundary.

C1-27 to 45 inches; gray (5Y 6/1) clay, white (5Y 8/1)

dry; many fine prominent yellowish brown (10YR 5/6)

mottles, brownish yellow (10YR 6/6) dry; massive; hard,

firm, sticky and plastic; common very fine roots; few

very fine irregular and common very fine tubular pores;

neutral; clear smooth boundary.

C2-45 to 60 inches; light brownish gray (2.5Y 6/2) clay,

white (2.5Y 8/2) dry; many coarse prominent light

olive brown (2.5Y 5/6) mottles, olive yellow (2.5Y

6/6) dry; massive; hard, firm, sticky and plastic;

common very fine roots; few very fine irregular and

common very fine tubular pores; neutral.

The particle-size control section has 60 to 75 percent

clay by weighted average. The thickness of the solum is 10

to 30 inches.

The Ap horizon has value of 2 or 3 when moist and 4 or

5 when dry and chroma of 1 to 3 when moist and dry. The

Bg horizon has hue of 10YR, 2.5Y, or 5Y, value of 3 to 6

when moist and 5 to 8 when dry, and chroma of 1 or 2

when moist and dry. The C horizon has hue of 2.5Y or 5Y,

value of 5 or 6 when moist and 7 or 8 when dry, and

chroma of 1 or 2 when moist and dry. In some pedons it

has thin strata of silt loam, silty clay loam, or sandy loam.

Blethen Series

The Blethen series consists of very deep, well drained

soils formed in glacial till, colluvium, and slope alluvium

with an admixture of volcanic ash and loess. These soils

are on side slopes and toe slopes of

foothills and landslides. Slopes are 5 to 60 percent. The

average annual precipitation is 50 to 70 inches, and the

mean annual air temperature is about 47 degrees F.

These soils are loamy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Blethen gravelly loam, 15 to 30 percent

slopes, 10 miles east of Lynden, 1,300 feet north and 500

feet east of the southwest corner of sec. 13, T. 40 N., R. 4

E.

Oi-0.75 to 0.25 inch; leaves, needles, twigs, and

cones.

Oa-0.25 inch to 0; decomposed needles, leaves, and

twigs; common very fine and fine roots.

A1-0 to 2 inches; dark brown (7.5YR 3/3) gravelly loam,

brown (7.5YR 4/3) dry; weak fine granular structure;

soft, very friable, nonsticky and slightly plastic; weakly

smeary; many very fine and fine and common medium

roots; many very fine irregular pores; about 15 percent

pebbles and 5 percent cobbles; NaF pH 9.8; slightly

acid; clear smooth boundary.

A2-2 to 6 inches; dark brown (7.5YR 3/3) gravelly loam,

strong brown (7.5YR 4/6) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

slightly plastic; weakly smeary; common very fine,

fine, and medium and few coarse roots; common

very fine irregular pores; about 15 percent pebbles

and 5 percent cobbles; NaF pH 10.1; moderately

acid; clear smooth boundary.

Bs1-6 to 18 inches; dark brown (7.5YR 4/4) very cobbly

loam, strong brown (7.5YR 5/6) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and slightly plastic; weakly smeary; common

very fine, fine, medium, and coarse roots; common

very fine irregular pores; about 25 percent pebbles

and 15 percent cobbles; NaF pH 10.1; moderately

acid; clear wavy boundary.

Bs2-18 to 28 inches; dark yellowish brown (10YR 4/4)

very cobbly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common fine and medium and few coarse roots;

common very fine irregular pores; about 25 percent

pebbles and 15 percent cobbles; NaF pH 10.5;

moderately acid; gradual smooth boundary.

Bs3-28 to 41 inches; dark yellowish brown (10YR 4/4)

very cobbly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; slightly hard,

very friable, nonsticky and nonplastic; weakly smeary;

few fine and medium roots; many very fine irregular

pores; about 30 percent pebbles and 20 percent

cobbles; NaF pH 10.1; moderately acid;
gradual smooth boundary.

C-41 to 60 inches; olive brown (2.5Y 4/4) very cobbly

loam, light yellowish brown (10YR 6/4) dry; massive;

hard, friable, nonsticky and nonplastic; weakly smeary;

few fine roots; few very fine irregular pores; about 40

percent pebbles and 20 percent cobbles; NaF pH 10.6;

slightly acid.

The thickness of the solum and of the part of the

profile influenced by volcanic ash is 26 to 50 inches.

The content of rock fragments in the control section

ranges from 35 to 60 percent. It includes 30 to 50

percent pebbles and 5 to 20 percent cobbles.

The A horizon has hue of 7.5YR or 10YR, value of 3 to 5

when moist and 4 to 7 when dry, and chroma of 2 or 3

when moist and 2 to 4 when dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 or 6 when dry, and chroma of 4 to 6

when moist and dry. It is very gravelly loam, very gravelly

silt loam, very cobbly loam, or very cobbly silt loam.

The C horizon has hue of 10YR or 2.5YR, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 3 or 4

when moist and dry. It is very gravelly loam, very gravelly

sandy loam, very cobbly loam, or very cobbly sandy loam.

Briscot Series

The Briscot series consists of very deep, poorly

drained soils that have been artificially drained. They

formed in alluvium on flood plains. Slopes are 0 to 2

percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are coarse-loamy, mixed, nonacid, mesic

Aeric Fluvaquents.

Typical pedon of Briscot silt loam, drained, 0 to 2

percent slopes, 3 miles south of Sumas, 400 feet south

and 2,400 feet east of the northwest corner of sec. 15, T.

40 N., R. 4 E.

Ap-0 to 9 inches; dark grayish brown (2.5Y 4/2) silt

loam, light gray (2.5Y 5/2) dry; moderate medium

subangular blocky structure parting to weak fine

granular; slightly hard, friable, slightly sticky and

slightly plastic; many very fine, common fine, and

few medium roots; many very fine irregular and

many very fine tubular pores; few fine pebbles;

moderately acid; abrupt smooth boundary.

C1-9 to 14 inches; dark grayish brown (2.5Y 4/2) silt

loam, light gray (2.5Y 7/2) dry; common fine

prominent yellowish brown (10YR 5/6) mottles,

brownish yellow (10YR 6/6) dry; moderate coarse

subangular blocky structure parting to weak fine

granular; slightly hard, friable, slightly sticky and

slightly plastic; many very fine, common fine, and

few medium roots; many very fine irregular and

many very fine tubular pores; moderately acid; abrupt

wavy boundary.

C2-14 to 22 inches; dark grayish brown (2.5Y 4/2) very

fine sandy loam, light gray (2.5Y 7/2) dry; many large

prominent yellowish brown (10YR 5/6) mottles,

brownish yellow (10YR 6/6) dry; massive; slightly hard,

friable, nonsticky and nonplastic; many very fine and

common fine roots; many very fine irregular and many

very fine tubular pores; moderately acid; abrupt smooth

boundary.

C3-22 to 34 inches; gray (5Y 6/1) fine sand, light gray

(5Y 7/1) dry; many large prominent olive brown (2.5Y

4/4) mottles, light yellowish brown (2.5Y 6/4) dry;

massive; soft, friable, nonsticky and nonplastic;

common very fine and few medium roots; many very

fine irregular pores; slightly acid; abrupt smooth

boundary.

C4-34 to 41 inches; gray (5Y 5/1) fine sandy loam, light

gray (5Y 7/1) dry; many large prominent olive brown

(2.5Y 4/4) mottles, light yellowish brown (2.5Y 6/4) dry;

massive; slightly hard, friable, nonsticky and

nonplastic; common very fine roots; many very fine

irregular pores; slightly acid; abrupt smooth boundary.

C5-41 to 60 inches; gray (5Y 5/1) and light brownish gray

(2.5Y 6/2) silt loam, light gray (5Y 7/1 and 2.5Y 7/2)

dry; many medium prominent yellowish brown (10YR

5/6) mottles, brownish yellow (10YR 6/6) dry; massive;

hard, friable, slightly sticky and slightly plastic; few very

fine roots; many very fine irregular and common very

fine tubular pores; slightly acid.

The control section is, by weighted average, 5 to 12

percent clay and 15 to 60 percent sand coarser than very

fine sand. These soils have an irregular distribution of

organic matter with increasing depth.

The A horizon has hue of 10YR or 2.5Y and value of 3 or

4 when moist and 6 or 7 when dry. The C horizon has hue

of 2.5Y or 5Y, value of 4 to 6 when moist and 7 when dry,

and chroma of 1 or 2 when moist and dry. It has mottles

with hue of 10YR or 2.5Y, value of 4 or 5 when moist, and

chroma of 4 to 6 when moist and dry. It is stratified silt

loam, very fine sandy loam, fine sandy loam, fine sand, or

sand.

Chuckanut Series

The Chuckanut series consists of deep and very deep,

well drained soils formed in a mixture of volcanic ash and

colluvium derived from glacial drift and
sandstone. These soils are on foothill side slopes, back

slopes, toe slopes, and landslides. Slopes are 3 to 60

percent. The average annual precipitation is 35 to 60

inches, and the mean annual air temperature is about 49

degrees F.

These soils are coarse-loamy, mixed, mesic Typic

Haplorthods.

Typical pedon of Chuckanut loam, 3 to 8 percent slopes,

3 miles southwest of Van Zandt, 1,000 feet south and 900

feet east of the northwest corner of sec. 19, T. 38 N., R. 4

E.

Ap-0 to 10 inches; dark brown (10YR 4/3) loam, brown

(10YR 5/3) dry; weak fine granular structure; soft, very

friable, nonsticky and nonplastic; weakly smeary; many

very fine roots; many very fine irregular pores; few soft

pebbles; NaF pH 11.0; moderately acid; clear smooth

boundary.

Bw1-10 to 12 inches; olive brown (2.5Y 4/4) sandy

loam, pale yellow (2.5Y 7/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common

very fine roots; few soft pebbles; NaF pH 11.0;

moderately acid; clear smooth boundary.

Bw2-12 to 24 inches; dark brown (10YR 3/3) gravelly

loam, pale brown (10YR 6/3) dry; weak fine subangular

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; common very fine roots; many very

fine irregular pores; about 15 percent hard pebbles

and 5 percent soft pebbles; NaF pH 10.2; moderately

acid; clear smooth boundary.

C-24 to 60 inches; olive brown (2.5Y 4/4) gravelly sandy

loam, pale yellow (2.5Y 7/4) dry; weak medium

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very

fine roots; many very fine irregular pores; about 20

percent hard pebbles and 60 percent soft pebbles;

NaF pH 10.2; slightly acid.

The depth to sandstone is 40 to more than 60 inches.

By weighted average, the content of rock fragments in the

control section is 0 to 15 percent hard pebbles, 35 to 60

percent soft pebbles, and 0 to 5 percent hard cobbles.

The A horizon has hue of 7.5YR or 10YR, value of 2 to 4

when moist and 4 to 6 when dry, and chroma of 2 or 3

when moist and 2 to 4 when dry.

The Bw horizon has hue of 7.5YR to 2.5Y, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 3 or 4

when moist and dry. It is gravelly loam, gravelly sandy

loam, or gravelly fine sandy loam.

The C 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 and dry. It is gravelly loam or gravelly

sandy loam.

Clendenen Series

The Clendenen series consists of shallow, moderately

well drained soils formed in a mixture of volcanic ash,

loess, and colluvium over glacial till. These soils are on

mountain back slopes and shoulder slopes. Slopes are 5 to

30 percent. The average annual precipitation is 80 to 100

inches, and the mean annual air temperature is about 41

degrees F.

These soils are loamy-skeletal, mixed, shallow Humic

Cryorthods.

Typical pedon of Clendenen gravelly silt loam, 5 to 30

percent slopes, 800 feet north and 800 feet west of the

southeast corner of sec. 33, T. 38 N., R. 6 E.

Oi-7 to 3 inches; undecomposed needles, leaves, and

twigs.

Oa-3 inches to 0; decomposed forest litter; many fine,

medium, and coarse roots.

E-0 to 2 inches; reddish gray (5YR 5/2) gravelly silt

loam, pinkish gray (5YR 6/2) dry; massive; slightly

hard, friable, nonsticky and nonplastic; weakly

smeary; about 20 percent pebbles; many very fine

roots; common fine irregular pores; very strongly acid;

abrupt smooth boundary.

Bhs-2 to 5 inches; strong brown (7.5YR 4/6) gravelly silt

loam, strong brown (7.5YR 5/6) dry; dark brown (7.5YR

3/2) organic stains, dark brown (7.5YR 4/4) dry;

moderate medium subangular blocky structure; slightly

hard, firm, nonsticky and nonplastic; weakly smeary;

common fine and medium roots; common very fine

irregular pores; about 15 percent pebbles; strongly

acid; clear smooth boundary.

Bs-5 to 16 inches; strong brown (7.5YR 5/6) very

gravelly silt loam, reddish yellow (7.5YR 6/6) dry;

moderate fine and medium subangular blocky

structure; slightly hard, firm, nonsticky and

nonplastic; weakly smeary; about 40 percent

pebbles; few fine roots; many very fine irregular

pores; moderately acid; abrupt smooth boundary.

2Cd-16 to 60 inches; pale brown (10YR 6/3), dense

glacial till that breaks to very gravelly loam, very pale

brown (10YR 7/3) dry; yellowish red (5YR 4/6) organic

stains, yellowish red (5YR 5/6) dry; massive; hard,

firm, slightly sticky and slightly plastic; about 50

percent pebbles; moderately acid.

The depth to dense, compact glacial till is 14 to 20

inches. The content of rock fragments in the control

section ranges from 40 to 65 percent.

The E horizon has hue of 5YR or 7.5YR and value of
4 or 5 when moist and 6 or 7 when dry.

The Bhs and Bs horizons have hue of 5YR or 7.5YR,

value of 3 or 4 when moist and 5 or 6 when dry, and

chroma of 4 to 6 when moist and dry. The fine-earth

fraction is loam or silt loam.

The 2Cd horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry. It is dense glacial till that breaks to

very gravelly loam or very gravelly sandy loam.

Clipper Series

The Clipper series consists of very deep, somewhat

poorly drained soils formed in an admixture of loess and

volcanic ash over glacial outwash. These soils are in

depressions on outwash terraces and outwash plains.

Slopes are 0 to 2 percent. The average annual precipitation

is 35 to 55 inches, and the mean annual air temperature is

about 50 degrees F.

These soils are coarse-loamy, mixed, mesic Aquic

Haplorthods.

Typical pedon of Clipper silt loam, drained, 0 to 2

percent slopes, 4 miles northeast of Lynden, 500 feet

north and 2,400 feet east of the southwest corner of sec.

34, T. 41 N., R. 3 E.

Ap-0 to 9 inches; very dark grayish brown (10YR 3/2) silt

loam, light brownish gray (10YR 6/2) dry; moderate

medium subangular blocky structure; hard, firm, slightly

sticky and slightly plastic; many very fine roots; many

very fine irregular and few fine tubular pores; about 5

percent pebbles; NaF pH 9.4; slightly acid; abrupt

smooth boundary.

E1-9 to 18 inches; grayish brown (2.5Y 5/2) and gray

(10YR 6/1) silt loam, light gray (2.5Y 7/2) and white

(10YR 8/1) dry; many medium prominent yellowish

brown (10YR 5/6) mottles, brownish yellow (10YR 6/6)

dry; moderate medium subangular blocky structure;

hard, friable, slightly sticky and slightly plastic;

common very fine roots; many very fine irregular and

few very fine tubular pores; few pebbles; strongly acid;

abrupt smooth boundary.

2E2-18 to 22 inches; grayish brown (2.5Y 5/2) and gray

(10YR 5/1) gravelly sandy loam, light gray (2.5Y 7/2 and

10YR 7/1) dry; many medium prominent strong brown

(7.5YR 5/8) mottles, reddish yellow (7.5YR 6/8) dry;

moderate medium subangular blocky structure; hard,

friable, slightly sticky and slightly plastic; few very fine

roots; many very fine irregular pores; about 30 percent

pebbles; moderately acid; clear smooth boundary.

2Bs-22 to 30 inches; yellowish brown (10YR 5/8) very

gravelly sandy loam, brownish yellow (10YR 6/8)

dry; many medium prominent grayish brown (2.5Y

5/2) mottles, light gray (2.5Y 7/2) dry; moderate

medium subangular blocky structure; slightly hard,

friable, slightly sticky and slightly plastic; very few

very fine roots; many very fine irregular pores; about

30 percent pebbles; moderately acid; clear smooth

boundary.

3C1-30 to 37 inches; dark grayish brown (2.5Y 4/2) and

grayish brown (2.5Y 5/2) very gravelly loamy sand,

light gray (2.5Y 7/2) dry; few fine prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; slightly hard, friable,

nonsticky and nonplastic; many very fine irregular

pores; about 50 percent pebbles and 5 percent

cobbles; moderately acid; clear smooth boundary.

3C2-37 to 60 inches; dark grayish brown (2.5Y 4/2) very

gravelly loamy sand, light brownish gray (2.5Y 6/2) dry;

many fine prominent yellowish brown (10YR 5/6)

mottles, brownish yellow (10YR 6/6) dry; massive; soft,

friable, nonsticky and nonplastic; many very fine

irregular pores; about 50 percent pebbles and 5

percent cobbles; moderately acid.

The thickness of the solum is 14 to 30 inches. By

weighted average, the solum has 10 to 18 percent clay

and the particle-size control section ranges from 15 to 35

percent rock fragments. The content of rock fragments

increases with increasing depth. It ranges from 10 to 25

percent in the solum and from 25 to 60 percent in the

substratum.

The A horizon has chroma of 2 or 3 when moist and dry.

The E horizon has hue of 10YR to 5Y, value of 5 or 6 when

moist and 7 or 8 when dry, and chroma of 1 or 2 when

moist and dry. It is silt loam, loam, gravelly loam, or

gravelly silt loam. The 2E horizon has hue of 10YR to 5Y,

value of 5 or 6 when moist and 7 or 8 when dry, and

chroma of 1 or 2 when moist and dry. It is mottled. It is

gravelly sandy loam or gravelly loam.

The 2Bs horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 6 or 7 when dry, and chroma of 1 to 8

when moist and dry. It is gravelly loam, gravelly sandy

loam, very gravelly loam, or very gravelly sandy loam.

The 3C horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry. It is massive or single grain and is

loose, soft, or slightly hard. It is very gravelly loamy sand

or very gravelly sand.

Comar Series

The Comar series consists of deep, moderately well

drained soils formed in a mixture of volcanic ash,
colluvium, and slope alluvium derived from siltstone and

glacial till. These soils are on foothill back slopes and toe

slopes. Slopes are 5 to 60 percent. The average annual

precipitation is 50 to 65 inches, and the mean annual

temperature is about 47 degrees F.

These soils are fine-loamy, mixed, mesic Typic

Haplorthods.

Typical pedon of Comar silt loam, 30 to 60 percent

slopes, 1.5 miles northeast of Deming, 2,200 feet due

south of the northwest corner of sec. 29, T. 39 N., R. 5 E.

Oi-5 to 4 inches; undecomposed needles, leaves, and

twigs.

Oa-4 inches to 0; decomposed forest litter; many very

fine, fine, medium, and coarse roots.

A-0 to 5 inches; dark brown (10YR 3/3) silt loam, brown

(10YR 5/3) dry; weak fine subangular blocky structure;

soft, very friable, slightly sticky and slightly plastic;

weakly smeary; many very fine, fine, medium, and

coarse roots; many fine irregular pores; about 30

percent weathered pebbles and 10 percent

unweathered pebbles; NaF pH 10.0; moderately acid;

clear smooth boundary.

Bs-5 to 16 inches; brown (10YR 4/3) silt loam,

yellowish brown (10YR 5/4) dry; weak fine subangular

blocky structure; soft, very friable, slightly sticky and

slightly plastic; weakly smeary; many very fine and

fine and common medium and coarse roots; many

fine irregular pores; about 20 percent weathered

pebbles and 5 percent unweathered pebbles; NaF pH

10.5; moderately acid; clear smooth boundary.

2C1-16 to 39 inches; light olive brown (2.5Y 5/4) silt

loam, very pale brown (10YR 7/3) dry; massive; very

hard, firm, sticky and plastic; many very fine and fine

and few medium roots; many fine and medium irregular

pores; about 75 percent weathered pebbles; NaF pH

9.4; strongly acid; clear smooth boundary.

2C2-39 to 44 inches; light olive brown (2.5Y 5/4) silt

loam; pale yellow (2.5YR 7/4) dry; massive; very hard,

firm, sticky and plastic; common very fine and fine and

few medium roots; many fine and medium irregular

pores; about 60 percent weathered pebbles; strongly

acid; abrupt wavy boundary.

2Cr-44 inches; siltstone.

The depth to siltstone is more than 40 inches. The

lower part of the control section has 20 to 30 percent

clay. The thickness of the part of the profile influenced by

volcanic ash is 14 to 24 inches. The content of rock

fragments in the particle-size control section ranges

from 0 to 25 percent unweathered pebbles and 15 to 80

percent weathered pebbles.

The A horizon has chroma of 3 or 4 when moist and

dry. The Bs horizon has value of 5 or 6 when dry and

chroma of 3 or 4 when moist and dry. It is loam or silt

loam. The 2C horizon has hue of 10YR or 2.5Y, value of 4

or 5 when moist and 5 to 8 when dry, and chroma of 3 or

4 when moist and dry. It is silt loam, silty clay loam, or

gravelly silt loam.

Crinker Series

The Crinker series consists of moderately deep, well

drained soils formed in an admixture of volcanic ash,

colluvium, slope alluvium, and glacial till derived dominantly

from phyllite. These soils are on high mountain back slopes

and shoulder slopes. Slopes are 30 to 60 percent. The

average annual precipitation is 80 to 95 inches, and the

mean annual air temperature is about 42 degrees F.

These soils are loamy-skeletal, mixed Typic

Cryorthods.

Typical pedon of Crinker very channery silt loam, 30 to

60 percent slopes, 5.5 miles east of Acme, 1,000 feet north

and 1,500 feet west of the southeast corner of sec. 7, T. 37

N., R. 6 E.

Oa-6 inches to 0; decomposed needles, leaves, and

twigs; many very fine, fine, medium, and coarse roots.

E1-0 to 3 inches; dark brown (7.5YR 4/2) very channery

loam, pinkish gray (7.5YR 7/2) and light gray (10YR

7/1) dry; massive; slightly hard, friable, slightly sticky

and slightly plastic; few very fine roots; many very fine

irregular pores; about 35 percent channers; extremely

acid; clear smooth boundary.

E2-3 to 6 inches; reddish brown (5YR 5/3) very

channery silt loam, pinkish gray (5YR 7/2) dry;

massive; slightly hard, friable, slightly sticky and

slightly plastic; few very fine roots; many very fine

irregular pores; about 40 percent channers; extremely

acid; abrupt smooth boundary.

Bhs-6 to 9 inches; strong brown (7.5YR 5/6) very

channery silt loam, brownish yellow (10YR 6/6) dry;

dark reddish brown (5YR 2/2) organic stains, very dark

gray (5YR 3/1) dry; massive; hard; very firm, nonsticky

and nonplastic; weakly smeary; many very fine irregular

pores; about 50 percent channers; NaF pH 11.0; very

strongly acid; clear smooth boundary.

Bs1-9 to 18 inches; yellowish brown (10YR 5/6) very

channery silt loam, brownish yellow (10YR 6/6) dry;

dark reddish brown (5YR 2/2) organic stains, dark
reddish brown (5YR 3/2) dry; massive; very hard, very

firm, nonsticky and nonplastic; weakly smeary; common

very fine irregular pores; about 55 percent channers;

NaF pH 12.0; strongly acid; clear smooth boundary.

Bs2-18 to 24 inches; yellowish brown (10YR 5/4) very

channery silt loam, light yellowish brown (10YR 6/4)

dry; dark reddish brown (5YR 2/2) organic stains, dark

reddish brown (5YR 3/2) dry; weak fine subangular

blocky structure; slightly hard, firm, slightly sticky and

slightly plastic; weakly smeary; many very fine irregular

pores; about 60 percent channers; NaF pH 12.0; very

strongly acid; clear smooth boundary.

R-24 inches; phyllite.

The depth to phyllite is 20 to 40 inches. The content of

hard phyllite rock fragments in the particle-size control

section ranges from 40 to 60 percent.

The E horizon has hue of 5YR, 7.5YR, or 10YR,

value of 4 or 5 when moist and 6 or 7 when dry, and

chroma of 1 to 3 when moist and dry.

The Bhs horizon has hue of 5YR, 7.5YR, or 10YR,

value of 3 to 5 when moist and 5 to 7 when dry, and

chroma of 4 to 6 when moist and dry. It is very channery

loam or very channery silt loam.

The Bs horizon has hue of 7.5YR or 10YR, value of 4 or 5

when moist and 5 to 7 when dry, and chroma of 4 to 6

when moist and dry. It is very channery loam or very

channery silt loam.

Some pedons have a C horizon. This horizon has hue

of 2.5Y or 5Y, value of 4 to 6 when moist and 6 to 8

when dry, and chroma of 4 to 6 when moist and dry. It is

very channery loam or extremely channery loam.

Cupples Series

The Cupples series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash and loess over glacial till. These soils are on

mountain back slopes and plateaus. Slopes are 5 to 60

percent. The average annual precipitation is 60 to 80

inches, and the mean annual air temperature is about 44

degrees F.

These soils are loamy-skeletal, mixed, frigid Typic

Haplorthods.

Typical pedon of Cupples gravelly loam, 5 to 30 percent

slopes, 5 miles northeast of Deming, 2,200 feet north and

2,400 feet west of the southeast corner of sec. 23, T. 39

N., R. 5 E.

Oi-7 to 5 inches; undecomposed needles and twigs. Oa-5

inches to 0; decomposed forest litter; many very fine,

fine, medium, and coarse roots.

E-0 to 2 inches; dark brown (7.5YR 4/2) gravelly fine

sandy loam, pinkish gray (7.5YR 6/2) dry; massive;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; many very fine and fine, common medium, and

few coarse roots; common very fine irregular pores;

about 15 percent pebbles and 5 percent cobbles; very

strongly acid; abrupt smooth boundary.

Bhs-2 to 5 inches; dark brown (7.5YR 3/4) and dark

yellowish brown (10YR 3/4) gravelly silt loam, strong

brown (7.5YR 5/6) and light yellowish brown (10YR 6/4)

dry; dark reddish brown (5YR 3/2) organic stains, dark

reddish brown (5YR 3/3) dry; moderate medium and

coarse subangular blocky structure; hard, very firm,

nonsticky and nonplastic; weakly smeary; common fine

and medium roots; common very fine irregular pores;

about 20 percent hard pebbles, 20 percent soft

pebbles, and 5 percent cobbles; strongly acid; abrupt

smooth boundary.

Bs-5 to 10 inches; dark brown (7.5YR 3/4) gravelly loam,

light yellowish brown (10YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many very fine and fine

and common medium and coarse roots; many very fine

irregular pores; about 10 percent hard pebbles, 30

percent soft pebbles, and 5 percent cobbles;

moderately acid; clear wavy boundary.

BC1-10 to 21 inches; olive brown (2.5Y 4/4) very gravelly

loam, yellowish brown (10YR 5/4) dry; weak medium

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many very fine and fine

and few medium and coarse roots; many very fine

irregular pores; about 30 percent hard pebbles, 25

percent soft pebbles, and 5 percent cobbles; slightly

acid; abrupt wavy boundary.

BC2-21 to 30 inches; dark yellowish brown (10YR 4/4)

very gravelly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common fine

and medium roots; many very fine irregular pores; about

40 percent hard pebbles; slightly acid; abrupt smooth

boundary.

2Cd-30 to 60 inches; light olive brown (2.5Y 5/4),

dense glacial till that breaks to very gravelly sandy

loam, pale yellow (2.5Y 7/4) dry; hard, friable,

nonsticky and nonplastic; about 45 percent hard

pebbles, 15 percent soft pebbles, and 5 percent

cobbles; slightly acid.

The depth to dense, compact glacial till is 20 to 40

inches. The content of rock fragments in the particle-
size control section ranges from 35 to 45 percent hard

pebbles, 5 to 25 percent soft pebbles, and 0 to 5 percent

cobbles.

The E horizon has hue of 7.5YR or 10YR and value of 3

or 4 when moist and 6 or 7 when dry.

The Bhs and Bs horizons have hue of 7.5YR or 10YR,

value of 3 or 4 when moist and 5 or 6 when dry, and

chroma of 4 to 6 when moist and dry. They are gravelly

loam or gravelly silt loam.

The BC horizon has hue of 10YR or 2.5Y and value of 4

or 5 when moist and 5 or 6 when dry.

The 2Cd horizon has value of 4 or 5 when moist and 6

or 7 when dry. It is dense glacial till that breaks to very

gravelly loam or very gravelly sandy loam.

Dekapen Series

The Dekapen series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash and loess over glacial till derived from

sandstone. These soils are on mountain plateaus and

back slopes. Slopes are 8 to 25 percent. The average

annual precipitation is 60 to 75 inches, and the mean

annual air temperature is about 44 degrees F.

These soils are coarse-loamy, mixed, frigid Typic

Haplorthods.

Typical pedon of Dekapen loam, 8 to 25 percent slopes,

2 miles southeast of Van Zandt, 1,700 feet north and 2,400

feet west of the southeast corner of sec. 15, T. 38 N., R. 5

E.

Oi-1 to 0.25 inch; undecomposed needles, leaves, and

twigs.

Oa-0.25 inch to 0; decomposed forest litter; many

medium roots.

E-0 to 2 inches; dark brown (7.5YR 3/2) gravelly silt

loam, pinkish gray (7.5YR 6/2) dry; weak fine

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; many fine and medium roots;

many fine irregular pores; about 10 percent soft

pebbles and 15 percent hard pebbles; strongly acid;

abrupt wavy boundary.

Bhs-2 to 8 inches; dark brown (7.5YR 3/4) loam, light

brown (10YR 6/4) dry; dark reddish brown (5YR 3/2)

organic stains, dark brown (7.5YR 4/4) dry; weak fine

and medium subangular blocky structure; slightly hard,

firm, nonsticky and nonplastic; weakly smeary; many

very fine and medium roots; common fine irregular

pores; about 40 percent soft pebbles, 10 percent soft

cobbles, and 5 percent hard pebbles; strongly acid;

clear wavy boundary.

Bs1-8 to 18 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 nonplastic; weakly smeary; many

very fine and fine and few medium roots; many fine

irregular pores; about 25 percent soft pebbles and 10

percent hard pebbles; strongly acid; clear wavy

boundary.

Bs2-18 to 24 inches; dark yellowish brown (10YR 3/4)

loam, yellowish brown (10YR 5/4) dry; weak medium

subangular blocky structure; slightly hard, friable,

slightly sticky and nonplastic; weakly smeary; many

very fine and fine roots; many medium irregular and

common medium tubular pores; about 30 percent soft

pebbles and 5 percent hard pebbles; strongly acid;

clear smooth boundary.

2C-24 to 31 inches; olive brown (2.5Y 4/4) loam, pale

yellow (2.5Y 7/4) dry; common fine distinct dark brown

(7.5YR 4/4) mottles, brown (7.5YR 5/4) dry; massive;

soft, friable, nonsticky and nonplastic; common very

fine and many fine and medium irregular and common

fine tubular pores; about 30 percent soft pebbles and

5 percent hard pebbles; strongly acid; abrupt smooth

boundary.

2Cd-31 to 60 inches; light olive brown (2.5Y 5/4), dense

glacial till that breaks to loam, pale yellow (2.5Y 7/4)

dry; common fine prominent strong brown (7.5YR 5/8)

mottles, reddish yellow (7.5YR 6/8) dry; massive; very

hard, very firm, nonsticky and nonplastic; few very fine

irregular pores; about 15 percent soft pebbles and 5

percent hard pebbles; strongly acid.

The thickness of the solum and of the part of the profile

influenced by volcanic ash is 24 to 32 inches. The depth to

dense, compact glacial till is 24 to 40 inches. By weighted

average, the content of rock fragments in the particle-size

control section is 25 to 40 percent soft pebbles, 0 to 15

percent soft cobbles, and 5 to 15 percent hard pebbles.

The E horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs and Bs horizons have hue of 7.5YR or

10YR, value of 3 to 5 when moist and 5 to 7 when dry, and

chroma of 4 to 6 when moist and dry. They are loam or

sandy loam.

The C horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry. It is loam or sandy loam.

The 2Cd horizon is dense glacial till that breaks to loam

or sandy loam. It has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry.
Deming Series

The Deming series consists of very deep, well drained

soils formed in a mixture of volcanic ash, slope alluvium,

and colluvium over unconsolidated glacial till. The slope

alluvium, colluvium, and glacial till are derived from

sandstone, conglomerate, metasedimentary rocks, and

volcanic rocks. These soils are on mountain back slopes.

Slopes are 5 to 60 percent. The average annual

precipitation is 80 to 95 inches, and the mean annual air

temperature is about 40 degrees F.

These soils are loamy-skeletal, mixed Humic

Cryorthods.

Typical pedon of Deming gravelly silt loam, 30 to 60

percent slopes, 6 miles northeast of Glacier, 1,900 feet

north and 800 feet west of the southeast corner of sec. 10,

T. 40 N., R. 6 E.

Oi-4 inches to 1 inch; undecomposed needles, twigs,

leaves, wood fragments, and moss.

Oa-1 inch to 0; decomposed needles, twigs, and

leaves; many very fine, fine, medium, and coarse

roots.

E-0 to 3 inches; dark brown (7.5YR 4/2) gravelly silt

loam, pinkish gray (7.5YR 6/2) dry; massive; slightly

hard, friable, nonsticky and nonplastic; many very fine

and fine and common medium and coarse roots; many

very fine irregular pores; about 20 percent pebbles and

5 percent cobbles; extremely acid; abrupt smooth

boundary.

Bhs-3 to 8 inches; dark reddish brown (5YR 3/4) gravelly

silt loam, yellowish red (5YR 4/6) dry; dark reddish

brown (5YR 2/2) organic stains on faces of peds, dark

brown (7.5YR 3/3) dry; moderate fine subangular

blocky structure; slightly hard, friable,. nonsticky and

nonplastic; weakly smeary; many fine and common

very fine, medium, and coarse roots; common very fine

irregular pores; about 20 percent pebbles and 5

percent cobbles; NaF pH less than 9.0; very strongly

acid; abrupt smooth boundary.

Bs1-8 to 15 inches; strong brown (7.5YR 4/6) very

gravelly loam, strong brown (7.5YR 5/6) dry; weak fine

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; many fine and medium

and common very fine and coarse roots; common very

fine irregular pores; about 35 percent pebbles and 5

percent cobbles; NaF pH 11.5; strongly acid; clear wavy

boundary.

Bs2-15 to 24 inches; dark brown (7.5YR 4/4) very

gravelly sandy loam, yellowish brown (10YR 5/6)

dry; weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine and few

medium roots; common very fine irregular pores;

about 45 percent pebbles and 10 percent cobbles;

NaF pH 11.5; very strongly acid; clear wavy

boundary.

BC-24 to 37 inches; dark yellowish brown (10YR 3/4)

extremely gravelly sandy loam, dark yellowish brown

(10YR 4/4) dry; massive; soft, very friable, nonsticky

and nonplastic; weakly smeary; common very fine and

fine and few medium roots; many very fine irregular

pores; about 50 percent pebbles, 10 percent cobbles,

and 5 percent stones; NaF pH 11.0; very strongly acid;

clear smooth boundary.

2C-37 to 60 inches; dark yellowish brown (10YR 4/4)

extremely gravelly loamy sand, light yellowish brown

(10YR 6/4) dry; massive; soft, very friable, nonsticky

and nonplastic; weakly smeary; few fine roots; many

fine irregular pores; about 60 percent pebbles and 5

percent cobbles; NaF pH 10.5; strongly acid.

The thickness of the part of the profile influenced by

volcanic ash is more than 40 inches. The thickness of the

solum is 24 to 40 inches. The content of rock fragments in

the control section ranges from 45 to 60 percent.

The E horizon has hue of 5YR or 7.5YR, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs horizon has hue of 5YR or 7.5YR, value of 3

or 4 when moist and 3 to 5 when dry, and chroma of 4 to

6 when moist and dry.

The Bs and BC horizons have hue of 7.5YR or 10YR,

value of 3 or 4 when moist and 4 or 5 when dry, and

chroma of 3 to 6 when moist and dry. They are very

gravelly loam, very gravelly sandy loam, or extremely

gravelly sandy loam.

The C horizon has hue of 10YR or 2.5Y, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 2 to 6

when moist and dry. It is very gravelly loam, very gravelly

sandy loam, or extremely gravelly loamy sand.

Diobsud Series

The Diobsud series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash and colluvium over glacial till derived from

phyllite. These soils are on mountain back slopes and

ridges. Slopes are 30 to 60 percent. The average annual

precipitation is 85 to 95 inches, and the mean annual air

temperature is about 42 degrees F.

These soils are coarse-loamy, mixed Humic

Cryorthods.

Typical pedon of Diobsud gravelly silt loam, 30 to 60

percent slopes, 9.5 miles east of Wickersham, 2,600
feet south and 100 feet east of the northwest corner of

sec. 35, T. 37 N., R. 6 E.

Oa-7 to 3 inches; undecomposed needles, leaves, and

twigs.

Oi-3 inches to 0; decomposed needles, leaves, and

twigs; many very fine and fine and few medium

roots.

E-0 to 4 inches; dark brown (7.5YR 3/2) gravelly silt

loam, pinkish gray (7.5YR 6/2) dry; massive; soft,

friable, nonsticky and nonplastic; common very fine,

fine, and medium roots; many very fine irregular pores;

about 30 percent pebbles; extremely acid; abrupt

smooth boundary.

Bhs-4 to 11 inches; dark brown (7.5YR 3/4) gravelly silt

loam, brown (7.5YR 5/4) dry; reddish brown (5YR 5/4)

organic stains, light reddish brown (5YR 6/4) dry;

moderate coarse subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine and few medium roots; many

very fine irregular pores; about 30 percent pebbles;

NaF pH 10.0; very strongly acid; abrupt irregular

boundary.

Bs-11 to 16 inches; strong brown (7.5YR 4/6) gravelly silt

loam, reddish yellow (7.5YR 6/6) dry; moderate coarse

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very fine,

fine, and medium roots; many very fine irregular pores;

about 25 percent pebbles; NaF pH 12.0; strongly acid;

clear irregular boundary.

BC-16 to 20 inches; brown (10YR 5/3) gravelly silt loam,

pale brown (10YR 6/3) dry; moderate medium

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very fine

and fine roots; many very fine irregular pores; about 30

percent pebbles; NaF pH 12.0; strongly acid; clear

smooth boundary.

C-20 to 37 inches; olive gray (5Y 5/2) gravelly loam, light

olive gray (5Y 6/2) dry; massive; slightly hard, friable,

nonsticky and nonplastic; very few very fine roots;

common very fine irregular pores; about 30 percent

pebbles; NaF pH 12.0; strongly acid; abrupt smooth

boundary.

2Cd-37 to 60 inches; olive gray (5Y 4/2), dense glacial till

that breaks to very gravelly loam, light olive gray (5Y

6/2) dry; massive; hard, firm, nonsticky and nonplastic;

about 45 percent pebbles; NaF pH 12.0; strongly acid.

The depth to dense, compact glacial till is 20 to 40

inches. The particle-size control section ranges from 20 to

35 percent hard phyllite fragments.

The E horizon has hue of 7.5YR or 10YR, value of 3

to 5 when moist and 6 to 8 when dry, and chroma of 1 or

2 when moist and dry.

The Bhs and Bs horizons have hue of 5YR or 7.5YR,

value of 3 to 5 when moist and 5 or 6 when dry, and

chroma of 4 to 6 when moist and dry. They are gravelly

loam or gravelly silt loam.

The BC horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 to 8 when dry, and chroma of 2 or 3

when moist and dry. It is gravelly loam or gravelly silt

loam.

The C horizon has hue of 2.5Y or 5Y, value of 4 or 5

when moist and 6 to 8 when dry, and chroma of 1 to 3

when moist and dry. It is gravelly loam or gravelly clay

loam.

The 2Cd horizon is dense glacial till that breaks to

gravelly loam or very gravelly loam. It has hue of 2.5Y or

5Y, value of 4 or 5 when moist and 5 to 7 when dry, and

chroma of 2 to 4 when moist and dry.

Edfro Series

The Edfro series consists of shallow, moderately well

drained soils formed in a mixture of volcanic ash, loess,

and colluvium over glacial till derived from dunite. These

soils are on high mountain shoulder slopes and back

slopes. Slopes are 8 to 60 percent. The average annual

precipitation is 85 to 105 inches, and the mean annual

temperature is about 41 degrees F.

These soils are loamy-skeletal, serpentinitic, shallow

Typic Cryorthods.

Typical pedon of Edfro very gravelly silt loam, 30 to 60

percent slopes, 7 miles east of Acme, 1,700 feet south

and 1,700 feet east of the northwest corner of sec. 4, T.

37 N., R. 6 E.

Oi-4 to 3.5 inches; needles, leaves, and twigs.

 Oa-3.5 inches to 0; decomposed needles, twigs, and

 bark; many very fine and common fine roots.

E-0 to 3 inches; brown (7.5YR 5/2) very gravelly silt

loam, pinkish gray (7.5YR 7/2) dry; massive; soft,

very friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine roots; many very fine

irregular pores; about 30 percent pebbles and 5

percent cobbles; NaF pH 10.0; extremely acid; abrupt

wavy boundary.

Bhs1-3 to 7 inches; strong brown (7.5YR 4/6) very

gravelly silt loam, strong brown (7.5YR 5/8) dry; dark

reddish brown (2.5YR 3/4) organic stains on faces of

peds, yellowish red (5YR 4/6) dry; moderate medium

and coarse subangular blocky structure; hard, very

firm, nonsticky and nonplastic; weakly smeary;

common very fine roots; many very fine irregular

pores; about 45 percent pebbles and
10 percent cobbles; NaF pH 11.5; very strongly

acid; clear wavy boundary.

Bhs2-7 to 17 inches; yellowish red (5YR 4/6) extremely

gravelly silt loam, yellowish red (5YR 5/6) dry; dark

reddish brown (2.5YR 3/4) organic stains on faces of

peds, reddish brown (5YR 4/4) dry; moderate medium

subangular blocky structure; slightly hard, firm,

nonsticky and nonplastic; weakly smeary; few very fine

roots; common very fine irregular pores; about 50

percent pebbles and 10 percent cobbles; NaF pH 12.0;

very strongly acid; clear wavy boundary.

Bhs3-17 to 19 inches; dark brown (7.5YR 4/4) extremely

gravelly loam, strong brown (7.5YR 4/6) dry; massive;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; very few very fine roots; many fine irregular

pores; about 60 percent pebbles; NaF pH 12.0; very

strongly acid; abrupt wavy boundary.

2Cd-19 to 60 inches; light yellowish brown (2.5Y 6/4),

dense compact glacial till that breaks to very gravelly

loam, light gray (2.5Y 7/2) dry; massive; extremely

hard, very firm, nonsticky and nonplastic; weakly

smeary; about 40 percent pebbles; NaF pH 10.5; very

strongly acid.

The depth to dense, compact glacial till ranges from 14

to 20 inches. The content of rock fragments in the control

section ranges from 40 to 60 percent, which includes 5 to

10 percent cobbles.

The E horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs horizon has hue of 5YR or 7.5YR, value of 3

to 5 when moist and 4 to 6 when dry, and chroma of 4 to

6 when moist and 6 to 8 when dry. It is very gravelly loam

or very gravelly silt loam.

The 2Cd horizon is dense, compact glacial till. It has hue

of 2.5Y or 5Y, value of 4 to 6 when moist and 4 to 7 when

dry, and chroma of 2 to 4 when moist and 1 to 4 when dry.

It is dense glacial till that breaks to very gravelly loam, very

gravelly sandy loam, or very gravelly loamy sand.

Edmonds Series

The Edmonds series consists of very deep, somewhat

poorly drained soils formed in an admixture of loess and

volcanic ash over glacial outwash. These soils are on

outwash terraces and outwash plains. Slopes are 0 to 2

percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are coarse-loamy over sandy or sandy

skeletal, mixed, mesic, ortstein Typic Sideraquods.

Typical pedon of Edmonds loam, in an area of

Edmonds-Woodlyn loams, drained, 0 to 2 percent slopes;

3 miles north of Ferndale, 1,200 feet south and 1,900 feet

east of the northwest corner of sec. 8, T. 39 N., R. 2 E.

Ap1-0 to 6 inches; dark brown (7.5YR 3/2) loam, pinkish

gray (7.5YR 6/2) dry; weak fine granular structure; soft,

very friable, nonsticky and nonplastic; many very fine

and fine roots; many very fine irregular pores; NaF pH

9.9; moderately acid; clear smooth boundary.

Ap2-6 to 11 inches; dark brown (7.5YR 4/2) loam, pinkish

gray (7.5YR 7/2) dry; weak fine granular structure;

slightly hard, friable, nonsticky and nonplastic; many

very fine and fine roots; many very fine irregular pores;

NaF pH 10.4; moderately acid; abrupt smooth

boundary.

E-11 to 18 inches; dark grayish brown (10YR 4/2) loam,

light gray (10YR 7/2) dry; moderate medium subangular

blocky structure; hard, firm, nonsticky and nonplastic;

many very fine roots; many very fine irregular pores;

NaF pH 11.0; moderately acid; abrupt smooth boundary.

2Bs-18 to 23 inches; dark brown (10YR 3/3) loamy sand,

pale brown (10YR 6/3) dry; many coarse prominent dark

yellowish brown (10YR 3/6) mottles, reddish yellow

(7.5YR 6/6) dry; weak medium subangular blocky

structure; slightly hard, friable, nonsticky and nonplastic;

few very fine roots; common very fine irregular pores;

NaF pH 11.1; moderately acid; abrupt smooth boundary.

2Bsm-23 to 37 inches; yellowish red (5YR 4/6 and 5/6)

loamy sand, reddish yellow (5YR 6/6 and 7.5YR 6/6)

dry; 75 percent ortstein concretions 2 to 6 inches in

diameter; many coarse prominent dark brown (10YR

4/3) mottles, very pale brown (10YR 7/3) dry; massive;

extremely hard ortstein and slightly hard matrix;

extremely firm ortstein and friable matrix; nonsticky and

nonplastic; few fine irregular pores in matrix; NaF pH

10.7; moderately acid; abrupt smooth boundary.

2C-37 to 60 inches; sand that is dominantly dark grayish

brown (2.5Y 4/2) but is variegated; light brownish gray

(2.5Y 6/2) dry; single grain; loose; many fine irregular

pores; about 5 percent pebbles; NaF pH 9.9; slightly

acid.

The thickness of the solum is 20 to 40 inches. The

thickness of the loamy part of the solum is 14 to 20

inches. The particle-size control section is 0 to 5 percent

pebbles by weighted average.

The Ap horizon has hue of 7.5YR or 10YR, value of
3 or 4 when moist and 6 or 7 when dry, and chroma of 1

to 3 when moist and dry. Reaction is strongly acid or

moderately acid. Pedons in uncultivated areas have an A

horizon. This horizon is 3 to 7 inches thick and is similar to

the Ap horizon.

The E horizon has hue of 7.5YR or 10YR, value of 3 to 5

when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry. It is loam or sandy loam.

The 213s horizon has hue of 7.5YR or 10YR in the matrix

and 5YR or 7.5YR in the ortstein or mottles. It has value of

3 to 5 when moist and 5 to 7 when dry. It has chroma of 2

to 4 when moist and dry in the matrix and 4 to 6 in the

ortstein or mottles. It is loamy sand or sand. It has a

subhorizon that is 50 to 80 percent ortstein occurring as

rounded or angular concretions, slaglike fragments, or

irregularly shaped indurated accretions. This horizon is at

least 5 inches thick.

The 2C horizon has hue of 10YR, 2.5Y, or 5Y, value of 3

or 4 when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry. It is coarse sand or sand.

Eliza Series

The Eliza series consists of very deep, very poorly

drained soils formed in alluvium. These soils are on flood

plains, deltas, and tidal flats. Slopes are 0 to 1 percent.

The average annual precipitation is about 30 to 40 inches,

and the mean annual air temperature is about 50 degrees

F.

These soils are coarse-loamy, mixed, acid, mesic

Sulfic Fluvaquents.

Typical pedon of Eliza silt loam, drained, 0 to 1 percent

slopes, 3 miles southwest of Ferndale, 1,200 feet north

and 1,200 feet east of the southwest corner of sec. 6, T.

38 N., R. 2 E.

Ap-0 to 11 inches; very dark grayish brown (10YR 3/2)

and dark grayish brown (10YR 4/2) silt loam, light

brownish gray (2.5Y 6/2) and light gray (10YR 7/2)

dry; moderate medium granular structure; very hard,

friable, slightly sticky and plastic; many very fine and

fine roots; many very fine irregular pores; moderately

acid when moist and strongly acid when dry; abrupt

smooth boundary.

Cg1-11 to 15 inches; very dark grayish brown (10YR 3/2)

and dark grayish brown (10YR 4/2) silt loam, light

brownish gray (10YR 6/2) and light gray (2.5Y 7/2) dry;

common medium prominent yellowish brown (10YR 5/6)

mottles, brownish yellow (10YR 6/6) dry; massive; very

hard, friable, slightly sticky and plastic; many very fine

and fine irregular pores; strongly acid when moist and

very strongly acid when dry; abrupt smooth boundary.

Cg2-15 to 19 inches; gray (5Y 5/1) fine sandy loam,

light gray (5Y 6/1) dry; many coarse prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; slightly hard, very friable,

nonsticky and nonplastic; common very fine and fine

and few medium roots; many very fine irregular pores;

very strongly acid when moist and dry; abrupt smooth

boundary.

Cg3-19 to 24 inches; dark gray (N 4/0) fine sandy loam,

gray (N 6/0) dry; many medium prominent dark

yellowish brown (10YR 4/6) mottles, yellowish brown

(10YR 5/6) dry; massive; soft, very friable, nonsticky

and slightly plastic; common very fine and fine and few

medium roots; many very fine irregular pores; very

strongly acid when moist and dry; clear smooth

boundary.

Cg4-24 to 34 inches; stratified dark gray (5Y 4/1) silt

loam, gray (N 5/0) fine sandy loam, and strong brown

(7.5YR 5/8) sand, gray (N 5/0), light gray (N 6/0), and

strong brown (7.5YR 5/8) dry; massive in silt loam

and fine sandy loam and single grain in sand; soft,

very friable, nonsticky and nonplastic; few very fine

and fine roots; many very fine and common fine

irregular pores; very strongly acid when moist and

extremely acid when dry; clear smooth boundary.

Cg5-34 to 44 inches; stratified dark grayish brown (2.5Y

4/2) silt loam, dark gray (5Y 4/1) fine sandy loam, and

yellowish brown (10YR 5/6) sand, light brownish gray

(2.5Y 6/2), light gray (N 7/0), and brownish yellow

(10YR 6/6) dry; massive in silt loam and fine sandy

loam and single grain in sand; soft, very friable,

nonsticky and nonplastic; very few very fine roots; very

strongly acid when moist and extremely acid when dry;

abrupt smooth boundary.

Cg6-44 to 52 inches; stratified dark gray (5Y 4/1) silt

loam and fine sandy loam and dark yellowish brown

(10YR 4/6) sand, light gray (N 6/0 and N 7/0) and

yellowish brown (10YR 5/6) dry; massive in silt loam

and fine sandy loam and single grain in sand; soft, very

friable, nonsticky and nonplastic very strongly acid

when moist and extremely acid when dry; abrupt

smooth boundary.

Cg7-52 to 60 inches; stratified dark gray (N 4/0) silt loam

and fine sandy loam and yellowish brown (10YR 5/8)

sand, gray (N 5/0 and N 6/0) and brownish yellow

(10YR 6/8) dry; massive in silt loam and fine sandy

loam and single grain in sand; soft, very friable,

nonsticky and nonplastic; neutral when moist and

strongly acid when dry.

The 10- to 40-inch particle-size control section ranges

from 10 to 18 percent clay. These soils have an irregular

distribution of organic matter with increasing depth.
The A horizon has hue of 10YR or 2.5Y, value of 3 or 4

when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry. It is slightly hard to very hard.

The Cg1horizon has hue of 10YR to 5Y, value of 3 or

4 when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry. It is slightly hard to very hard. It is silt

loam, very fine sandy loam, or fine sandy loam.

The Cg2 and Cg3 horizons have hue of 2.5Y, 5Y, or N,

value of 4 or 5 when moist and 6 or 7 when dry, and

chroma of 0 to 2 when moist and dry. They are fine sandy

loam or very fine sandy loam.

The Cg4, Cg5, and Cg6 horizons have hue of 2.5Y, 5Y,

or N in the silt loam and fine sandy loam and 7.5YR or

10YR in the sand. They have value of 4 or 5 when moist

and 5 to 7 when dry in the silt loam and fine sandy loam

and value of 4 or 5 when moist and 5 or 6 when dry in the

sand. When moist and dry, they have chroma of 0 to 2 in

the silt loam and fine sandy loam and 6 to 8 in the sand.

They are stratified silt loam, fine sandy loam, and sand.

Reaction is very strongly acid, strongly acid, or moderately

acid when moist and very strongly acid or strongly acid

when dry.

The Cg7 horizon has hue of 5Y or N, value of 2 to 4

when moist and 3 to 6 when dry, and chroma of 0 or 1

when moist and dry. The sand strata have hue of 7.5YR or

10YR and value of 5 when moist and 8 when dry. They are

stratified silt loam, fine sandy loam, and sand. Reaction is

moderately acid, slightly acid, or neutral when moist and is

extremely acid or very strongly acid when dry.

Everett Series

The Everett series consists of deep and very deep,

somewhat excessively drained soils formed in a mixture of

volcanic ash and alluvium over glacial outwash and glacial

till. These soils are on outwash terraces and moraines.

Slopes are 2 to 35 percent. The average annual

precipitation is 35 to 45 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are sandy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Everett very gravelly sandy loam, in an

area of Everett complex, 2 to 8 percent slopes (fig. 6); 4.5

miles east of Blaine, 1,000 feet north and 2,000 feet west

of the southeast corner of sec. 2, T. 40 N., R. 1 E.

Oi-4 inches to 0; undecomposed needles and twigs.

E-0 to 2 inches; dark brown (7.5YR 4/2) very gravelly

sandy loam, pinkish gray (7.5YR 6/2) dry; massive;

soft, very friable, nonsticky and nonplastic; many very

fine, fine, and medium and common coarse roots;

many very fine irregular pores; about 40

Figure 6.-Profile of Everett very gravelly sandy loam, in an area of

Everett complex, 2 to 8 percent slopes. The sandy-skeletal

material is at a depth of 18 inches. Depth is marked in feet.

percent pebbles; extremely acid; abrupt wavy

boundary.

Bs1-2 to 6 inches; dark brown (7.5YR 3/4) very gravelly

sandy loam, dark brown (7.5YR 4/4) dry; dark reddish

brown (5YR 3/3) organic stains, moist and dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine and fine, common medium, and few coarse roots;

many very fine irregular
pores; about 40 percent pebbles; NaF pH 10.5;

moderately acid; clear irregular boundary.

Bs2-6 to 11 inches; dark brown (7.5YR 4/4) very gravelly

sandy loam, light yellowish brown (10YR 6/4) dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine and fine and common medium roots; many very

fine irregular pores; about 45 percent pebbles and 5

percent cobbles; NaF pH 12.0; moderately acid; clear

wavy boundary.

Bs3-11 to 18 inches; dark brown (7.5YR 4/4) very

gravelly sandy loam, light yellowish brown (10YR 6/4)

dry; weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary; many

very fine and fine and common medium roots; many

very fine irregular pores; about 50 percent pebbles and

5 percent cobbles; NaF pH 11.5; moderately acid;

abrupt wavy boundary.

2C1-18 to 28 inches; very gravelly sand; variegated

mostly with hue of 10YR; single grain; loose; common

very fine and few fine roots; many fine irregular

pores; about 55 percent pebbles and 5 percent

cobbles; moderately acid; gradual smooth boundary.

2C2-28 to 45 inches; variegated extremely gravelly sand;

massive; loose, friable, nonsticky and nonplastic; few

fine roots; many fine irregular pores; about 65 percent

pebbles and 5 percent cobbles; compact in place;

moderately acid; clear smooth boundary.

2C3-45 to 60 inches; variegated very gravelly sand;

single grain; loose; many fine irregular pores; about 55

percent pebbles and 5 percent cobbles; moderately

acid.

The part of the profile influenced by volcanic ash and the

thickness of the solum range from 14 to 24 inches. The

content of rock fragments in the control section ranges

from 35 to 60 percent in the upper part and from 50 to 75

percent in the lower part. Some pedons are underlain by

dense glacial till or glaciomarine drift at 40 to 60 inches.

Other pedons have a perched water table at 40 to 60

inches from December through April.

The E horizon has hue of 5YR or 7.5YR and value of 6

or 7 when dry. Some pedons have an A horizon and do

not have an E horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 4 to 6

when moist and dry. The upper part of the Bs horizon is

gravelly sandy loam, gravelly loam, or very gravelly sandy

loam. The lower part is very gravelly loam or very gravelly

sandy loam. Some pedons do not have organic stains in

the Bs horizon.

The 2C horizon is variegated very gravelly or

extremely gravelly sand or very gravelly or extremely

gravelly loamy sand. The degree of compaction and iron

cementation varies but is generally weak.

Everson Series

The Everson series consists of very deep, poorly

drained soils formed in alluvium, lacustrine deposits, and

glacial outwash with an admixture of loess. These soils

are in depressions on outwash terraces. Slopes are 0 to 2

percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are clayey over sandy or sandy-skeletal,

mixed, nonacid, mesic Typic Humaquepts.

Typical pedon of Everson silt loam, drained, 0 to 2

percent slopes, about 1.5 miles southeast of Everson,

200 feet south and 100 feet east of the northwest corner

of sec. 3, T. 39 N., R. 4 E.

Ap-0 to 7 inches; very dark grayish brown (10YR 3/2) silt

loam, dark grayish brown (10YR 4/2) dry; moderate

coarse subangular blocky structure parting to weak

medium granular; hard, friable, slightly sticky and

slightly plastic; many very fine and fine roots; many

very fine irregular pores; strongly acid; clear smooth

boundary.

Bg-7 to 19 inches; grayish brown (10YR 5/2) silty clay,

light gray (10YR 7/2) dry; many large prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; moderate coarse subangular blocky

structure; hard, friable, sticky and plastic; many very

fine roots; many very fine irregular pores; moderately

acid; abrupt smooth boundary.

2C1-19 to 29 inches; dark grayish brown (2.5Y 4/2) sand,

light gray (2.5Y 7/2) dry; many large prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; soft, very friable, nonsticky

and nonplastic; common very fine roots; many very fine

irregular pores; moderately acid; clear smooth

boundary.

2C2-29 to 40 inches; grayish brown (2.5Y 5/2) sand,

light gray (2.5Y 7/2) dry; many large prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; slightly hard, friable,

nonsticky and nonplastic; few very fine roots; many

very fine irregular pores; about 5 percent pebbles;

moderately acid; abrupt smooth boundary.

3C3-40 to 54 inches; dark grayish brown (2.5Y 4/2) very

gravelly loamy sand, grayish brown (2.5Y 5/2) dry;

many medium prominent strong brown (7.5YR 5/6)

mottles, reddish yellow (7.5YR 6/6) dry; massive;

weakly cemented; slightly hard, friable,
nonsticky and nonplastic; very few fine roots; common

very fine irregular pores; about 40 percent pebbles;

slightly acid; abrupt smooth boundary.

4C4-54 to 62 inches; olive brown (2.5Y 4/4) gravelly

sand, light olive brown (2.5Y 5/4) dry; common large

prominent yellowish brown (10YR 5/6) mottles,

brownish yellow (10YR 6/6) dry; single grain; loose;

many very fine irregular pores; about 25 percent

pebbles; slightly acid; abrupt smooth boundary.

5C5-62 to 70 inches; grayish brown (2.5Y 5/2) fine sand,

light gray (2.5Y 7/2) dry; many large prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; soft, very friable; many very

fine irregular pores; slightly acid.

The upper part of the control section has 35 to 45

percent clay. The lower part has 0 to 5 percent clay. The

solum is 14 to 26 inches thick. By weighted average, the

lower part of the control section has 0 to 10 percent

pebbles. Some pedons have gravelly or very gravelly strata

below a depth of 40 inches.

The Ap horizon has value of 2 or 3 when moist and 4 or

5 when dry and chroma of 1 or 2 when moist and dry.

The Bg horizon has hue of 10YR, 2.5Y, or 5Y, value of

4 to 6 when moist and 7 or 8 when dry, and chroma of 1

or 2 when moist and dry. It is silty clay, silty clay loam,

clay loam, or clay.

The C horizon has hue of 2.5Y or 5Y, value of 4 or 5

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. The fine-earth fraction is loamy sand

or sand. The weighted average of rock fragments ranges

from 0 to 15 percent, although individual subhorizons

contain as much as 45 percent pebbles.

Fishtrap Series

The Fishtrap series consists of very deep, very poorly

drained soils formed in herbaceous and woody organic

deposits over glaciofluvial deposits. These soils are in

depressions on outwash terraces. Slopes are 0 to 2

percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are sandy or sandy-skeletal, mixed, euic,

mesic Terric Medisaprists.

Typical pedon of Fishtrap muck, drained, 0 to 2 percent

slopes, 6 miles southwest of Lynden, 2,600 feet south and

2,100 feet east of the northwest corner of sec. 28, T. 40 N.,

R. 2 E.

Oa1-0 to 7 inches; very dark grayish brown (10YR

3/2) muck, dark grayish brown (10YR 4/2) dry;

moderate coarse subangular blocky structure;

slightly hard, friable, nonsticky and nonplastic; many

very fine, fine, and medium roots; many fine irregular

pores; moderately acid; clear smooth boundary.

Oa2-7 to 19 inches; very dark brown (10YR 2/2) muck,

very dark grayish brown (10YR 3/2) dry; moderate

coarse subangular blocky structure; slightly hard,

friable, nonsticky and nonplastic; many very fine, fine,

and medium roots; many fine irregular pores; strongly

acid; abrupt smooth boundary.

2C1-19 to 36 inches; dark grayish brown (2.5Y 4/2) sand,

light brownish gray (2.5Y 6/2) dry; many coarse

prominent dark yellowish brown (10YR 4/6) mottles,

brownish yellow (10YR 6/6) dry; massive; soft, loose,

nonsticky and nonplastic; few very fine roots; many fine

irregular pores; strongly acid; clear smooth boundary.

2C2-36 to 60 inches; dark gray (N 4/0) sand, gray (N

6/0) dry; single grain; loose; many fine irregular pores;

very strongly acid.

The organic material is 16 to 51 inches thick. Fibers are

mostly from grasses and sedges, but pedons contain as

much as 15 percent wood fragments. The fiber content

ranges from 10 to 50 percent when unrubbed and from 2 to

15 percent when rubbed. Thin, discontinuous layers of

volcanic ash and diatomaceous earth (0.5 inch to 2 inches

thick) are at a depth of 24 to 48 inches in some pedons.

The Oa horizon has hue of 5YR to 10YR or of N,

value of 2 to 4 when moist and 2 to 5 when dry, and

chroma of 0 to 3 when moist and dry.

The 2C horizon has hue of 2.5Y, 5Y, or N, value of 4 or

5 when moist and 5 to 7 when dry, and chroma of 0 to 2

when moist and dry. It is loamy sand, sand, or gravelly

sand.

Gallup Series

The Gallup series consists of very deep, well drained

soils formed in a mixture of volcanic ash, loess,

unconsolidated glacial till, and colluvium and slope alluvium

derived from sandstone and metasedimentary rocks. These

soils are on mountain back slopes. Slopes are 30 to 80

percent. The average annual precipitation is 80 to 100

inches, and the mean annual temperature is about 41

degrees F.

These soils are coarse-loamy, mixed Humic

Cryorthods.

Typical pedon of Gallup silt loam, cold, 60 to 80 percent

slopes, 6 miles southwest of Glacier, 2,000 feet
north and 2,400 feet east of the southwest corner of

sec. 33, T. 39 N., R. 6 E.

Oi-12 to 4 inches; undecomposed needles, twigs,

leaves, and moss.

Oa-4 inches to 0; decomposed needles, twigs, and

leaves; many very fine and medium and common

coarse roots.

E-0 to 3 inches; dark brown (7.5YR 3/2) silt loam, brown

(7.5YR 5/2) dry; massive; very hard, very firm, slightly

sticky and slightly plastic; common very fine, fine,

medium, and coarse roots; common very fine irregular

pores; about 5 percent pebbles; NaF pH 9.0; extremely

acid; abrupt smooth boundary.

Bhs-3 to 6 inches; dark reddish brown (5YR 3/3) gravelly

silt loam, dark brown (7.5YR 4/4) dry; dark reddish

brown (5YR 2/2) organic stains on faces of peds, dark

reddish brown (5YR 3/3) dry; moderate medium

subangular blocky structure; hard, firm, slightly sticky

and nonplastic; weakly smeary; many very fine and fine

and common medium and coarse roots; common very

fine irregular pores; about 15 percent pebbles and 5

percent cobbles; NaF pH 10.5; very strongly acid; clear

smooth boundary.

Bs1-6 to 14 inches; yellowish red (5YR 4/6) gravelly

loam, strong brown (7.5YR 5/6) dry; dark reddish

brown (5YR 2/2) organic stains on faces of peds, dark

reddish brown (5YR 3/2) dry; moderate medium

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; common very

fine, fine, and medium roots; common very fine

irregular pores; about 20 percent pebbles and 5

percent cobbles; NaF pH 11.0; very strongly acid; clear

wavy boundary.

Bs2-14 to 27 inches; dark brown (7.5YR 3/4) gravelly

loam, strong brown (7.5YR 5/6) dry; weak fine and

medium subangular blocky structure; slightly hard,

friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine and few medium roots;

common very fine irregular pores; about 20 percent

pebbles, 5 percent cobbles, and 5 percent stones;

NaF pH 12.0; very strongly acid; abrupt wavy

boundary.

BC-27 to 39 inches; dark yellowish brown (10YR 4/4)

gravelly loam, light yellowish brown (10YR 6/4) dry;

weak medium subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

few fine and medium roots; common very fine irregular

pores; about 30 percent unweathered pebbles and 15

percent weathered pebbles; NaF pH 11.5; very

strongly acid; clear smooth boundary.

C1-39 to 51 inches; dark yellowish brown (10YR 4/6)

gravelly loam, brownish yellow (10YR 6/6) dry;

massive; soft, very friable, nonsticky and nonplastic;

weakly smeary; few fine roots; common very fine

irregular pores; about 20 percent unweathered pebbles

and 10 percent weathered pebbles; NaF pH 12.0; very

strongly acid; clear smooth boundary.

C2-51 to 60 inches; dark yellowish brown (10YR 4/4)

gravelly loam, light yellowish brown (10YR 6/4) dry;

massive; soft, very friable, nonsticky and nonplastic;

weakly smeary; common fine irregular pores; about 20

percent weathered pebbles; NaF pH 12.0; very strongly

acid.

The thickness of the solum is 25 to 39 inches. The

content of unweathered rock fragments in the control

section is 20 to 35 percent and that of weathered

fragments is 5 to 25 percent.

The E horizon has hue of 5YR or 7.5YR, value of 3 or

4 when moist and 5 or 6 when dry, and chroma of 1 or 2

when moist and dry.

The Bhs and Bs horizons have hue of 5YR or 7.5YR,

value of 3 or 4 when moist and 4 to 6 when dry, and

chroma of 3 to 6 when moist and dry. They are loam, silt

loam, gravelly loam, or gravelly silt loam.

The BC horizon has hue of 7.5YR or 10YR, value of 3 to 5

when moist and 5 or 6 when dry, and chroma of 3 to 6

when moist and dry. It is gravelly loam or gravelly silt loam.

The C horizon has hue of 10YR or 2.5Y, value of 3 or 4

when moist and 5 to 7 when dry, and chroma of 2 to 6

when moist and dry. It is gravelly loam, gravelly silt loam,

or gravelly sandy loam.

Getchell Series

The Getchell series consists of moderately deep,

moderately well drained soils formed in an admixture of

volcanic ash and colluvium over glacial till. These soils are

on high mountain back slopes and plateaus. Slopes are 3

to 60 percent. The average annual precipitation is 70 to 85

inches, and the mean annual air temperature is about 42

degrees F.

These soils are coarse-loamy, mixed, ortstein Typic

Cryorthods.

Typical pedon of Getchell loam, 3 to 30 percent slopes,

4 miles southwest of Van Zandt, 800 feet south and 1,400

feet west of the northeast corner of sec. 22, T. 38 N., R. 4

E.

Oi-5 to 4 inches; undecomposed needles, twigs,

cones, and dead moss.

Oa-4 inches to 0; decomposed needles, twigs, cones,

and roots and rotted wood; many very fine and fine

and common medium roots.

E-0 to 1 inch; dark gray (7.5YR 4/1) loam, gray (7.5YR

6/1) dry; weak fine subangular blocky structure;
slightly hard, firm, nonsticky and nonplastic; weakly

smeary; common very fine and fine roots; common

very fine irregular pores; about 5 percent hard pebbles

and 10 percent soft pebbles; NaF pH 10.5; very

strongly acid; abrupt wavy boundary.

Bhs-1 to 4 inches; dark brown (7.5YR 4/4) loam, light

brown (7.5YR 6/4) dry; dark reddish brown (5YR 3/3)

organic stains, dark reddish brown (5YR 3/4) dry;

moderate fine subangular blocky structure; soft, friable,

nonsticky and nonplastic; weakly smeary; common very

fine, fine, and medium roots; common very fine irregular

pores; about 5 percent hard pebbles and 10 percent soft

pebbles; NaF pH 11.5; very strongly acid; abrupt

smooth boundary.

Bs-4 to 12 inches; dark brown (7.5YR 4/4) sandy loam,

strong brown (7.5YR 4/6) dry; weak fine granular

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; common very fine, fine, and medium

and few coarse roots; common very fine irregular pores;

about 5 percent hard pebbles and 20 percent soft

pebbles; NaF pH 11.0; strongly acid; clear smooth

boundary.

BC-12 to 36 inches; brown (10YR 5/3) sandy loam, light

gray (10YR 7/2) dry; weak fine subangular blocky

structure; soft, friable, nonsticky and nonplastic; weakly

smeary; common very fine, fine, and medium and many

coarse roots; common very fine irregular pores; about

10 percent hard pebbles and 20 percent soft pebbles;

NaF pH 11.0; strongly acid; clear smooth boundary.

2Cd-36 to 60 inches; yellowish brown (10YR 5/4), dense

glacial till that breaks to sandy loam, very pale brown

(10YR 7/3) dry; massive; hard, firm, nonsticky and

nonplastic; about 10 percent hard pebbles and 20

percent soft pebbles; strongly acid.

The depth to dense, compact glacial till is 20 to 40

inches. The content of rock fragments in the control

section ranges from 5 to 15 percent hard pebbles and

from 10 to 20 percent soft pebbles.

The E horizon has hue of 5YR to 10YR, value of 4 or 5

when moist and 5 to 7 when dry, and chroma of 1 or 2

when moist and dry.

The Bhs horizon has hue of 5YR or 7.5YR, value of 3

to 5 when moist and 4 to 6 when dry, and chroma of 2 to

4 when moist and dry. It is loam or silt loam.

The Bs horizon has hue of 7.5YR or 10YR, value of 4 to

6 when moist and dry, and chroma of 3 to 6 when moist

and dry. It is loam, silt loam, or sandy loam.

The BC horizon has hue of 7.5YR or 10YR, value of 4

or 5 when moist and 5 to 7 when dry, and chroma of 2 to

4 when moist and dry. It is loam or sandy loam.

The 2Cd horizon has value of 4 or 5 when moist and

chroma of 2 to 4 when moist and dry. It is dense glacial

till that breaks to loam or sandy loam.

Hale Series

The Hale series consists of very deep, somewhat poorly

drained soils formed in an admixture of loess and volcanic

ash over glacial outwash. These soils are on outwash

terraces. Slopes are 0 to 2 percent. The average annual

precipitation is 40 to 55 inches, and the mean annual air

temperature is 50 degrees F.

These soils are coarse-loamy over sandy or sandyskeletal, mixed, mesic Aquic Haplorthods.

Typical pedon of Hale silt loam, drained, 0 to 2 percent

slopes, 1.5 miles northwest of Lynden, 2,500 feet north

and 100 feet west of the southeast corner of sec. 8, T. 40

N., R. 3 E.

Ap-0 to 10 inches; very dark grayish brown (10YR 3/2) silt

loam, light brownish gray (10YR 6/2) dry; moderate fine

and medium subangular blocky structure; hard, friable,

slightly sticky and slightly plastic; many very fine and

fine roots; many fine irregular and few fine tubular

pores; NaF pH 9.4; moderately acid; abrupt smooth

boundary.

Bs1-10 to 14 inches; mottled olive gray (5Y 5/2), dark

brown (7.5YR 3/4), and strong brown (7.5YR 4/6) silt

loam, light gray (5Y 7/2), strong brown (7.5YR 5/6),

and reddish yellow (7.5YR 6/6) dry; moderate medium

subangular blocky structure; very hard, friable, slightly

sticky and slightly plastic; many very fine roots; many

very fine irregular and few very fine tubular pores;

moderately acid; clear smooth boundary.

Bs2-14 to 19 inches; mottled grayish brown (2.5Y 5/2),

dark brown (7.5YR 3/4), and strong brown (7.5YR 4/6)

loam, light gray (2.5Y 7/2), strong brown (7.5YR 5/6),

and reddish yellow (7.5YR 6/6) dry; weak medium

subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; many very fine roots;

many very fine irregular and few very fine tubular

pores; strongly acid; clear smooth boundary.

Bs3-19 to 24 inches; mottled olive gray (5Y 5/2), dark

brown (7.5YR 4/4), and strong brown (7.5YR 4/6)

loam, light gray (5Y 7/2), brown (7.5YR 5/4), and

reddish yellow (7.5YR 6/6) dry; weak medium

subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; many very fine roots;

many very fine irregular pores; strongly acid; abrupt

smooth boundary.

Bw-24 to 26 inches; mottled olive gray (5Y 4/2 and

5/2) and strong brown (7.5YR 4/6) loam, grayish

brown (2.5Y 5/2), light gray (2.5Y 7/2), and strong

brown (7.5YR 5/6) dry; moderate medium
subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; common very fine

roots; many very fine irregular pores; strongly acid;

abrupt smooth boundary.

2C1-26 to 38 inches; dark grayish brown (2.5Y 4/2)

loamy fine sand, light brownish gray (2.5Y 6/2) dry;

common medium prominent strong brown (7.5YR 4/6)

mottles, strong brown (7.5YR 5/8) dry; massive; soft,

very friable, nonsticky and nonplastic; common very

fine roots; many very fine irregular pores; strongly acid;

abrupt smooth boundary.

2C2-38 to 60 inches; sand that is dominantly dark

grayish brown (2.5Y 4/2) but is variegated, light

brownish gray (2.5Y 6/2) dry; single grain; loose; few

very fine roots; many very fine irregular pores; slightly

acid.

The thickness of the solum is 15 to 30 inches. By

weighted average, the upper part of the particle-size

control section has 10 to 18 percent clay and 0 to 10

percent pebbles and the lower part has 0 to 5 percent

clay and 0 to 15 percent pebbles, although individual

subhorizons contain as much as 25 percent pebbles.

The A horizon has value of 5 or 6 when dry and

chroma of 2 or 3 when moist and dry. The Bs horizon has

dominant hue of 2.5Y or 5Y, value of 4 to 6 when moist

and 5 to 8 when dry, and chroma of 2 or 3 when moist

and dry. It is loam, silt loam, or fine sandy loam and

contains 0 to 15 percent ortstein concretions.

The 2C horizon has hue of 10YR, 2.5Y, or 5Y, value of 4

or 5 when moist and 5 to 7 when dry, and chroma of 2 to

4 when moist and dry. It is massive or single grain. It is

loamy fine sand, loamy sand, sand, gravelly loamy sand,

or gravelly sand.

Hallenton Series

The Hallenton series consists of very deep, very poorly

drained soils formed in a mixture of volcanic ash, loess,

and glaciomarine drift. These soils are in ponded areas on

glaciomarine drift plains. Slopes are 0 to 1 percent. The

average annual precipitation is 30 to 40 inches, and the

mean annual air temperature is about 50 degrees F.

These soils are fine-loamy, mixed, nonacid, mesic

Typic Haplaquepts.

Typical pedon of Hallenton silt loam, 0 to 1 percent

slopes, 8 miles east of Blaine, 1,400 feet south and 1,500

feet east of the northwest corner of sec. 4, T. 40 N., R. 2

E.

A-0 to 11 inches; grayish brown (10YR 5/2) silt loam,

light gray (10YR 7/2) dry; weak fine subangular blocky

structure; slightly hard, friable, nonsticky and

nonplastic; common very fine roots; few fine

irregular pores; moderately acid; clear smooth

boundary.

Bg-11 to 19 inches; light brownish gray (2.5Y 6/2) silt

loam, white (2.5Y 8/2) dry; few medium prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; slightly hard, friable,

nonsticky and nonplastic; few very fine roots; strongly

acid; clear smooth boundary.

Cg-19 to 60 inches; olive (5Y 5/3) silt loam, white (5Y

8/2) dry; many coarse prominent yellowish brown

(10YR 5/6) mottles, brownish yellow (10YR 6/6) dry;

massive; very hard, firm, slightly sticky and plastic;

strongly acid.

The thickness of the solum is 14 to 30 inches. By

weighted average, the control section has 18 to 30

percent clay and 0 to 10 percent pebbles, although

individual horizons contain 0 to 25 percent pebbles.

The A horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bg horizon has hue of 10YR or 2.5Y, value of 5 to 7

when moist and 6 to 8 when dry, and chroma of 2 or 3

when moist and dry. It is silt loam or loam.

The Cg horizon has hue of 2.5Y, 5Y, or N, value of 4 to

6 when moist and 6 to 8 when dry, and chroma of 0 to 3

when moist and dry. It is loam, clay loam, silt loam, or silty

clay loam.

Hannegan Series

The Hannegan series consists of shallow, well drained

soils formed in a mixture of volcanic ash, loess, and

colluvium derived from phyllite and sandstone. These soils

are on mountain shoulder slopes. Slopes are 15 to 40

percent. The average annual precipitation is 90 to 110

inches, and the mean annual air temperature is about 40

degrees F.

These soils are loamy-skeletal, mixed Humic Lithic

Cryorthods.

Typical pedon of Hannegan very gravelly loam, 15 to 40

percent slopes, 4 miles southwest of Glacier, 2,500 feet

south and 2,000 feet west of the northeast corner of- sec.

26, T. 39 N., R. 6 E.

Oi-5 to 4 inches; undecomposed needles, leaves, and

twigs.

Oa-4 inches to 0; decomposed needles, leaves, and

twigs; many very fine, fine, and medium roots.

E1-0 to 1 inch; dark brown (7.5YR 3/2) very gravelly

loam, pinkish gray (7.5YR 7/2) dry; massive; slightly

hard, friable, nonsticky and nonplastic; common very

fine roots; many very fine irregular pores;
about 30 percent hard pebbles, 15 percent hard

cobbles, and 20 percent weathered pebbles;

extremely acid; clear smooth boundary.

E2-1 to 5 inches; dark reddish brown (5YR 3/2) very

gravelly loam, reddish gray (5YR 5/2) dry; weak fine

granular structure; slightly hard, friable, nonsticky and

nonplastic; common very fine roots; many very fine

irregular pores; about 30 percent soft pebbles; very

strongly acid; clear smooth boundary.

Bhs-5 to 12 inches; dark yellowish brown (10YR 3/4) very

cobbly loam, light yellowish brown (10YR 6/4) dry; dark

brown (7.5YR 3/2) organic stains, dark brown (7.5YR

4/4) dry; weak fine subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

few very fine roots; many very fine irregular pores;

about 20 percent hard pebbles, 30 percent hard

cobbles, and 20 percent weathered pebbles; NaF pH

11.5; very strongly acid; clear smooth boundary.

Bs-12 to 17 inches; dark yellowish brown (10YR 3/4) and

pale brown (10YR 6/3) very gravelly loam, light

yellowish brown (10YR 6/4) and very pale brown (10YR

8/3) dry; weak fine subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

few very fine roots; many very fine irregular pores;

about 30 percent hard pebbles, 10 percent hard

cobbles, and 10 percent weathered pebbles; NaF pH

12.0; very strongly acid; abrupt smooth boundary.

R-17 inches; fractured phyllite.

The depth to phyllite and the thickness of the part of the

profile influenced by volcanic ash range from 14 to 20

inches. The content of rock fragments in the particle-size

control section is 25 to 35 percent hard pebbles, 10 to 30

percent hard cobbles, and 10 to 20 percent weathered

pebbles.

The E horizon has hue of 5YR to 10YR, value of 3 to 5

when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 4 to 6 when dry, and chroma of 4 to 6

when moist or dry. It is very gravelly loam or very cobbly

loam.

The Bs horizon has hue of 7.5YR to 2.5Y, value of 3 to 6

when moist and 5 to 8 when dry, and chroma of 3 or 4

when moist and dry. It is very gravelly loam or very cobbly

loam.

Hartnit Series

The Hartnit series consists of moderately deep, well

drained soils formed in a mixture of volcanic ash, glacial till,

and colluvium derived from sandstone and

metasedimentary rocks. These soils are on mountain

back slopes and plateaus. Slopes are 5 to 80 percent.

The average annual precipitation is 70 to 90 inches, and

the mean air temperature is about 42 degrees F.

These soils are coarse-loamy, mixed Typic

Cryorthods.

Typical pedon of Hartnit loam, in an area of Saar-Hartnit

complex, 5 to 40 percent slopes; 4 miles southwest of

Glacier, 500 feet north and 1,500 feet west of the southeast

corner of sec. 22, T. 39 N., R. 6 E.

Oa-3 inches to 0; decomposed needles, leaves, and

twigs; many very fine, fine, medium, and coarse roots.

E-0 to 4 inches; dark brown (7.5YR 4/2) loam, pinkish

gray (7.5YR 7/2) dry; massive; slightly hard, very

friable, nonsticky and nonplastic; many very fine, fine,

medium, and coarse roots; many very fine irregular

pores; about 5 percent hard pebbles and 5 percent

weathered pebbles; very strongly acid; abrupt wavy

boundary.

Bhs-4 to 10 inches; dark brown (7.5YR 4/6) loam, strong

brown (7.5YR 5/6) dry; dark reddish brown (5YR 3/3)

organic stains, dark brown (7.5YR 4/4) dry; moderate

medium subangular blocky structure; slightly hard,

friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine roots; many very fine

irregular pores; about 10 percent hard pebbles and 10

percent weathered pebbles; NaF pH 10.0; strongly

acid; clear irregular boundary.

Bs-10 to 17 inches; dark yellowish brown (10YR 4/6)

loam, brownish yellow (10YR 6/6) dry; weak medium

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very fine

and fine roots; many very fine irregular pores; about 10

percent hard pebbles and 15 percent weathered

pebbles; NaF pH 11.5; moderately acid; clear smooth

boundary.

BC-17 to 27 inches; olive brown (2.5Y 4/4) gravelly loam,

pale yellow (2.5Y 7/4) dry; weak fine subangular

blocky structure; soft, friable, nonsticky and nonplastic;

weakly smeary; few very fine roots; many very fine

irregular pores; about 20 percent hard pebbles and 20

percent weathered pebbles; NaF pH 12.0; moderately

acid; clear smooth boundary.

C1-27 to 36 inches; dark yellowish brown (10YR 3/4)

very gravelly loam, light olive brown (2.5Y 5/4) dry;

weak fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine irregular pores; about 40 percent hard pebbles and

20 percent soft pebbles; moderately acid; clear smooth

boundary.
C2-36 to 39 inches; olive brown (2.5Y 4/4) very gravelly

loam, light gray (2.5Y 7/2) dry; massive; slightly hard,

friable, nonsticky and nonplastic; weakly smeary;

common very fine irregular pores; about 50 percent

hard pebbles and 20 percent weathered pebbles; NaF

pH 11.0; moderately acid; clear smooth boundary.

R-39 inches; sandstone.

The depth to sandstone or metasedimentary rock and

the thickness of the part of the profile influenced by

volcanic ash are 20 to 40 inches. The content of hard rock

fragments in the particle-size control section ranges from

15 to 35 percent, although individual horizons contain as

much as 50 percent hard rock fragments. The content of

weathered rock fragments ranges from 0 to 25 percent by

weighted average.

The E horizon has hue of 5YR to 10YR, value of 3 or 4

when moist and 5 to 7 when dry, and chroma of 1 or 2

when moist or dry.

The Bhs and Bs horizons have hue of 7.5YR or

10YR, value of 3 or 4 when moist and 5 to 7 when dry, and

chroma of 4 to 6 when moist and dry. They are gravelly

loam or gravelly silt loam.

The C horizon has hue of 10YR or 2.5Y, value of 3 or 4

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. It is gravelly loam, gravelly silt loam,

or very gravelly loam.

Heisler Series

The Heisler series consists of very deep, well drained

soils formed in a mixture of volcanic ash and loess over

colluvium derived from glacial till high in content of phyllite.

These soils are on mountain back slopes. Slopes are 8 to

60 percent. The average annual precipitation is 50 to 70

inches, and the mean annual air temperature is about 47

degrees F.

These soils are loamy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Heisler very gravelly silt loam, 30 to 60

percent slopes, 4.5 miles northwest of Wickersham, 1,300

feet south and 2,300 feet west of the northeast corner of

sec. 23, T. 37 N., R. 5 E.

Oi-4 to 3 inches; undecomposed needles, leaves, and

twigs.

Oa-3 inches to 0; decomposed forest litter.

E-0 to 1 inch; gray (5YR 6/1) silt loam, pinkish gray

(7.5YR 7/2) dry; massive; slightly hard, friable,

nonsticky and nonplastic; many very fine roots;

common very fine irregular pores; about 10 percent

pebbles; NaF pH 10.0; very strongly acid; abrupt

smooth boundary.

Bs1-1 to 6 inches; dark brown (7.5YR 4/4) very gravelly

silt loam, light brown (7.5YR 6/4) dry; dark reddish

brown (5YR 3/3) organic stains, reddish brown (5YR

5/3) dry; weak medium subangular blocky structure

parting to weak medium granular; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; common very

fine and fine roots; common very fine and fine irregular

pores; about 35 percent pebbles and 15 percent

cobbles; NaF pH 11.5; strongly acid; gradual wavy

boundary.

Bs2-6 to 24 inches; yellowish brown (10YR 5/6) very

gravelly silt loam, light yellowish brown (10YR 6/4) dry;

moderate fine subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

many very fine, fine, and medium roots; common very

fine and fine irregular pores; about 30 percent

channers, 20 percent pebbles,

and 10 percent cobbles; NaF pH 11.0; strongly acid;

gradual smooth boundary.

BC-24 to 32 inches; light olive brown (2.5Y 5/4)

extremely channery loam, light gray (2.5Y 7.2) dry;

weak coarse subangular blocky structure; slightly hard,

friable, slightly sticky and slightly plastic; weakly

smeary; common very fine and fine and few medium

roots; common very fine and fine irregular pores; about

40 percent channers, 10 percent pebbles, and 15

percent cobbles; NaF pH 10.5; moderately acid; clear

smooth boundary.

C1-32 to 38 inches; pale olive (5Y 6/4) extremely

channery sandy loam, light gray (5Y 7/2) dry; massive;

soft, friable, nonsticky and slightly plastic; weakly

smeary; few very fine and fine roots; common very fine

and fine irregular pores; about 55 percent channers, 10

percent pebbles, and 10 percent cobbles; NaF pH 10.5;

moderately acid; clear smooth boundary.

C2-38 to 60 inches; pale olive (5Y 6/3) extremely

channery sandy loam, light gray (5Y 7/2) dry; massive;

soft, friable, slightly sticky and slightly plastic; weakly

smeary; few very fine and fine roots; common very fine

and fine irregular pores; about 55 percent channers,

10 percent pebbles, and 15 percent cobbles; NaF pH

10.5; moderately acid.

The thickness of the solum is 22 to 35 inches. The

content of rock fragments in the control section ranges

from 40 to 60 percent channers and pebbles and from 5 to

15 percent cobbles.

The E horizon has hue of 5YR to 10YR, value of 3 to 6

when moist and 4 to 7 when dry, and chroma of 2 to 4

when moist and dry. Some pedons do not have an E

horizon.

The Bs horizon has hue of 5YR to 10YR, value of 4 or 5

when moist and 5 or 6 when dry, and chroma of 4
to 6 when moist. It is very channery loam, very channery

silt loam, or very channery fine sandy loam.

The C horizon has hue of 2.5Y or 5Y, value of 5 or 6

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry. It is very channery or extremely

channery loam or sandy loam.

Hinker Series

The Hinker series consists of moderately deep, well

drained soils formed in a mixture of volcanic ash, loess,

and colluvium derived dominantly from phyllite. These soils

are on high mountain shoulder slopes. Slopes are 5 to 60

percent. The average annual precipitation is 85 to 100

inches, and the mean annual air temperature is about 41

degrees F.

These soils are loamy-skeletal, mixed Humic

Cryorthods.

Typical pedon of Hinker very channery silt loam, 30 to 60

percent slopes, 1,200 feet north and 750 feet west of the

southeast corner of sec. 8, T. 37 N., R. 6 E.

Oi-15 to 12 inches; undecomposed needles, leaves,

and twigs.

Oa-12 inches to 0; decomposed organic mat; many

very fine, fine, medium, and coarse roots.

E1-0 to 4 inches; pinkish gray (7.5YR 6/2) very channery

loam, pinkish gray (7.5YR 7/2) dry; massive; soft,

friable, slightly sticky and slightly plastic; many very

fine and fine roots; many very fine irregular pores;

about 40 percent channers and 5 percent cobbles;

extremely acid; clear smooth boundary.

E2-4 to 6 inches; brown (7.5YR 5/3) very channery silt

loam, pinkish gray (7.5YR 7/2) dry; massive; slightly

hard, friable, slightly sticky and slightly plastic; many

very fine and fine roots; many very fine irregular pores;

about 40 percent channers and 5 percent cobbles;

extremely acid; abrupt smooth boundary.

Bhs1-6 to 11 inches; dark brown (7.5YR 4/4) very

channery silt loam, brown (7.5YR 5/4) dry; dark

reddish brown (5YR 3/2) organic stains, moist and dry,

on 60 percent of faces of peds; moderate very coarse

subangular blocky structure; slightly hard, firm, slightly

sticky and slightly plastic; weakly smeary; common

very fine and fine roots; many very fine irregular pores;

about 40 percent channers; NaF pH 9.6; extremely

acid; clear irregular boundary.

Bhs2-11 to 15 inches; dark brown (7.5YR 4/4) very

channery loam, light yellowish brown (10YR 6/4) dry;

dark reddish brown (5YR 2/2) organic stains, dark

reddish brown (5YR 3/2) dry, on 40 percent of faces of

peds; moderate very coarse subangular

blocky structure; slightly hard, firm, slightly sticky and

slightly plastic; weakly smeary; few very fine and fine

roots; about 35 percent channers; NaF pH 12.0; very

strongly acid; clear irregular boundary.

Bhs3-15 to 21 inches; dark brown (7.5YR 4/4) and

yellowish brown (10YR 5/4) very channery silt loam,

yellowish brown (10YR 5/6) and light yellowish brown

(10YR 6/4) dry; very dusky red (2.5YR 2/2) organic

stains, dusky red (2.5YR 3/2) dry, on 30 percent of

faces of peds; moderate very coarse subangular blocky

structure; slightly hard, firm, slightly sticky and slightly

plastic; weakly smeary; few very fine and fine roots;

many very fine irregular pores; about 50 percent

channers; NaF pH 11.5; very strongly acid; abrupt wavy

boundary.

2R-21 inches; unweathered phyllite.

The depth to phyllite and the thickness of the part of the

profile influenced by volcanic ash are 20 to 40 inches. The

control section contains from 35 to 65 percent hard rock

fragments and from 15 to 35 percent soft rock fragments.

The E horizon has hue of 5YR to 10YR, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist and dry. The Bhs horizon has hue of 5YR to

10YR, value of 3 to 5 when moist and 4 to 6 when dry, and

chroma of 4 to 6 when moist and 4 to 8 when dry. It is very

cobbly loam, very cobbly silt loam, very channery loam, or

very channery silt loam.

Hovde Series

The Hovde series consists of very deep, poorly drained

soils formed in marine sediments and gravelly coastal

beach deposits. These soils are on marine terraces.

Slopes are 0 to 2 percent. The average annual

precipitation is 25 to 40 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are sandy-skeletal, mixed, mesic Aeric

Haplaquents.

Typical pedon of Hovde silt loam, 0 to 2 percent slopes,

1.5 miles west of Marietta, 1,000 feet south and 2,300 feet

east of the northwest corner of sec. 18, T. 38 N., R. 2 E.

Oi-1 inch to 0; leaves and twigs.

A-0 to 9 inches; very dark grayish brown (10YR 3/2) silt

loam, light brownish gray (2.5Y 6/2) dry; few fine

prominent strong brown (7.5YR 5/6) mottles, reddish

yellow (7.5YR 6/6) dry; weak medium granular

structure; slightly hard, friable, slightly sticky and

slightly plastic; many very fine, fine, medium, and

coarse roots; many very fine irregular
 pores; about 10 percent pebbles; moderately

acid; abrupt smooth boundary.

2C1-9 to 13 inches; very dark grayish brown (2.5Y 3/2)

extremely gravelly coarse sand, grayish brown (2.5Y

5/2) dry; single grain; loose; many very fine roots;

many very fine irregular pores; about 60 percent

pebbles; moderately acid; abrupt smooth boundary.

2C2-13 to 29 inches; dark brown (10YR 4/3) very

gravelly coarse sand, brown (10YR 5/3) dry; single

grain; loose; common very fine roots; many very fine

irregular pores; about 40 percent pebbles;

moderately acid; abrupt smooth boundary.

2C3-29 to 39 inches; dark grayish brown (2.5Y 4/2) very

gravelly coarse sand, grayish brown (2.5Y 5/2) dry;

single grain; loose; common very fine roots; many very

fine irregular pores; about 45 percent pebbles;

moderately acid; clear smooth boundary.

2C4-39 to 60 inches; very dark grayish brown (10YR 3/2)

very gravelly sand, dark grayish brown (10YR 4/2) dry;

single grain; loose; few very fine roots; many very fine

irregular pores; about 50 percent pebbles; strongly

acid.

The content of rock fragments in the control section

ranges from 40 to 55 percent by weighted average. The A

horizon has hue of 10YR or 2.5Y and value of 3 or 4 when

moist and 5 or 6 when dry. The C horizon has hue of 10YR

or 2.5Y, value of 3 or 4 when moist and 4 to 6 when dry,

and chroma of 2 or 3 when moist and dry. It is very

gravelly sand, very gravelly coarse sand, extremely

gravelly sand, or extremely gravelly coarse sand.

Hozomeen Series

The Hozomeen series consists of shallow, moderately

well drained soils formed in a mixture of loess, volcanic

ash, and colluvium over glacial till. These soils are on

mountain back slopes. Slopes are 20 to 45 percent. The

average annual precipitation is 80 to 95 inches, and the

mean annual air temperature is about 43 degrees F.

These soils are loamy-skeletal, mixed, shallow Typic

Cryorthods.

Typical pedon of Hozomeen gravelly loam, 20 to 45

percent slopes, 7 miles southeast of Van Zandt, 2,000 feet

north and 300 feet west of the southeast corner of sec.

29, T. 38 N., R. 6 E.

Oi-6 to 5 inches; undecomposed needles, leaves, and

twigs.

Oa-5 inches to 0; decomposed needles, leaves, and

twigs; common very fine and many fine and medium

roots.

E-0 to 1 inch; dark reddish brown (5YR 3/2) gravelly

fine sandy loam, reddish gray (5YR 5/2) dry;

massive; slightly hard, friable, nonsticky and

nonplastic; common very fine, fine, and medium

roots; many very fine irregular pores; about 20

percent pebbles; extremely acid; abrupt irregular

boundary.

Bhs-1 to 4 inches; dark reddish brown (5YR 3/3)

gravelly loam, reddish brown (5YR 5/3) dry; dark

reddish brown (2.5YR 3/4) organic stains on faces of

peds, dark reddish brown (5YR 3/3) dry; weak fine

subangular blocky structure parting to weak medium

granular; slightly hard, friable, nonsticky and

nonplastic; weakly smeary; common very fine and fine

and few medium roots; many very fine irregular pores;

about 25 percent pebbles; NaF pH 9.4; very strongly

acid; clear smooth boundary.

Bs1-4 to 8 inches; dark reddish brown (5YR 3/4) very

gravelly loam, yellowish red (5YR 4/6) dry; weak medium

subangular blocky structure parting to weak medium

granular; soft, very friable, nonsticky and nonplastic;

weakly smeary; many very fine and fine and few medium

roots; many very fine irregular pores; about 40 percent

pebbles; NaF pH 10.5; very strongly acid; clear smooth

boundary.

Bs2-8 to 13 inches; dark brown (7.5YR 3/4) very gravelly

loam, brown (7.5YR 5/4) dry; weak medium subangular

blocky structure; soft, friable, nonsticky and nonplastic;

weakly smeary; common very fine and few fine and

medium roots; many very fine irregular pores; about 40

percent pebbles and 5 percent cobbles; NaF pH 11.5;

strongly acid; clear smooth boundary.

BC-13 to 18 inches; strong brown (7.5YR 4/6) very

gravelly loam, strong brown (7.5YR 5/6) dry; massive;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; very few very fine and fine roots; common

very fine irregular pores; about 50 percent pebbles;

NaF pH 10.5; strongly acid; abrupt smooth boundary.

2Cd-18 to 60 inches; olive brown (2.5Y 4/4), dense,

compact glacial till that breaks to gravelly loam, light

yellowish brown (2.5Y 6/4) dry; massive; hard, firm,

nonsticky and nonplastic; weakly smeary; about 30

percent pebbles; NaF pH 10.0; strongly acid.

The depth to dense, compact glacial till and the

thickness of the part of the profile influenced by volcanic

ash range from 14 to 20 inches. The content of rock

fragments in the control section ranges from 35 to 45

percent.

The E horizon has hue of 5YR to 10YR, value of 3 to 6

when moist and 5 to 7 when dry, and chroma of 1 to 3

when moist and dry.
The Bhs and Bs horizons have hue of 5YR to 7.5YR,

value of 3 or 4 when moist and 4 or 5 when dry, and

chroma of 3 to 6 when moist and dry. They are gravelly

loam, gravelly silt loam, very gravelly loam, or very gravelly

silt loam.

The BC horizon has hue of 7.5YR to 2.5Y and value of

3 to 5 when moist and 4 to 6 when dry. It is very gravelly

loam or very gravelly silt loam.

The 2Cd horizon has hue of 2.5Y or 5Y, value of 4 to 6

when moist and dry, and chroma of 2 to 4 when moist and

dry. It is dense glacial till that breaks to gravelly loam or

very gravelly loam.

Jackman Series

The Jackman series consists of very deep, well

drained soils formed in a mixture of volcanic ash,

colluvium, slope alluvium, and glacial till derived from

dunite. These soils are on mountain back slopes. Slopes

are 30 to 60 percent. The average annual precipitation is

75 to 90 inches, and the mean annual air temperature is

about 42 degrees F.

These soils are loamy-skeletal, serpentinitic Typic

Cryorthods.

Typical pedon of Jackman gravelly silt loam, 30 to 60

percent slopes, 10.5 miles east of Wickersham, 1,600 feet

north and 2,600 feet east of the southwest corner of sec.

36, T. 37 N., R. 6 E.

Oi-2 inches to 0; undecomposed needles, leaves, and

twigs.

Bs1-0 to 9 inches; dark yellowish brown (10YR 4/4)

gravelly silt loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary; many

very fine irregular pores; about 20 percent pebbles;

NaF pH 10.5; strongly acid; abrupt smooth boundary.

Bs2-9 to 15 inches; yellowish brown (10YR 5/6) very

gravelly silt loam, brownish yellow (10YR 6/6) dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common very

fine and fine and few medium roots; many very fine

irregular pores; about 30 percent pebbles; NaF pH 9.8;

moderately acid; clear smooth boundary.

Bs3-15 to 24 inches; strong brown (7.5YR 5/6) very

gravelly silt loam, reddish yellow (7.5YR 6/6) dry; weak

coarse subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common very

fine and fine and few medium roots; many very fine

irregular pores; about 45 percent pebbles; NaF pH

10.0; moderately acid; abrupt smooth boundary.

BC-24 to 32 inches; yellowish brown (10YR 5/6) very

gravelly loam, brownish yellow (10YR 6/6) dry;

massive; soft, friable, nonsticky and nonplastic;

weakly smeary; few fine roots; common very fine

irregular pores; about 45 percent pebbles and 5

percent cobbles; NaF pH 10.0; moderately acid; clear

smooth boundary.

C-32 to 60 inches; dark brown (7.5YR 4/4) very gravelly

loam, reddish yellow (7.5YR 6/6) dry; massive; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

common very fine irregular pores; about 55 percent

pebbles; NaF pH 10.0; moderately acid.

The thickness of the solum is 15 to 36 inches. The

content of rock fragments in the control section ranges

from 35 to 60 percent. It includes 0 to 5 percent cobbles.

Some pedons have an E horizon above the Bs1

horizon. The E horizon is less than 0.5 inch thick.

The Bs horizon has hue of 7.5YR or 10YR, value of 4

or 5 when moist and 5 or 6 when dry, and chroma of 4 to 6

when moist and dry. It is dominantly very gravelly loam or

very gravelly silt loam. In some pedons, however, the

upper part is gravelly silt loam.

The C horizon has hue of 7.5YR or 10YR, value of 4 to 6

when moist and 6 or 7 when dry, and chroma of 4 to 6

when moist and dry. It is very gravelly loam or very gravelly

sandy loam.

Jorgensen Series

The Jorgensen series consists of very deep, somewhat

excessively drained soils formed in a mixture of loess,

volcanic ash, and glacial outwash derived from dunite.

These soils are on outwash terraces. Slopes are 3 to 15

percent. The mean annual precipitation is 90 to 100 inches,

and the mean annual air temperature is about 42 degrees

F.

These soils are sandy-skeletal, serpentinitic Humic

Cryorthods.

Typical pedon of Jorgensen gravelly silt loam, 3 to 15

percent slopes, 10 miles southeast of Van Zandt, 2,600

feet south and 700 feet west of the northeast corner of sec.

16, T. 37 N., R. 6 E.

Oi-18 to 7 inches; undecomposed needles, leaves,

and twigs; common very fine, fine, and medium

roots.

Oa-7 inches to 0; decomposed organic mat; many very

 fine and common fine and medium roots.

E-0 to 3 inches; brown (7.5YR 5/2) gravelly silt loam,

pinkish gray (7.5YR 6/2) dry; massive; slightly hard,

friable, slightly sticky and nonplastic; common very
fine and few fine and medium roots; few very fine

irregular pores; about 25 percent pebbles; extremely

acid; abrupt wavy boundary.

Bhs1-3 to 5 inches; dark brown (7.5YR 4/4) gravelly silt

loam, strong brown (7.5YR 5/6) dry; black (5YR 2/1)

organic stains on 80 percent of the soil matrix, dark

reddish brown (5YR 3/2) dry; strong medium

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very

fine, fine, and medium roots; few very fine irregular

pores; about 20 percent pebbles; extremely acid; clear

wavy boundary.

Bhs2-5 to 8 inches; dark brown (7.5YR 3/4) very gravelly

loam, strong brown (7.5YR 5/6) dry; reddish brown

(5YR 4/4) organic stains on faces of peds, strong

brown (7.5YR 4/6) dry; strong very coarse subangular

blocky structure; hard, firm, nonsticky and nonplastic;

weakly smeary; few very fine, fine, and medium roots;

few very fine irregular pores; about 25 percent pebbles

and 10 percent cobbles; NaF pH 12.0; very strongly

acid; clear irregular boundary.

Bs1-8 to 13 inches; dark yellowish brown (10YR 4/6)

very gravelly sandy loam, brownish yellow (10YR 6/6)

dry; moderate medium subangular blocky structure

parting to moderate coarse granular; slightly hard,

friable, nonsticky and nonplastic; weakly smeary; few

very fine and very few fine roots; common very fine

irregular pores; about 30 percent pebbles and 15

percent cobbles; NaF pH 12.0; moderately acid; clear

irregular boundary.

Bs2-13 to 19 inches; dark yellowish brown (10YR 4/4)

extremely gravelly sandy loam, brownish yellow (10YR

6/6) dry; weak medium subangular blocky structure;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; few very fine and very few fine roots; common

fine irregular pores; about 50 percent pebbles and 15

percent cobbles; NaF pH 12.0; moderately acid; clear

wavy boundary.

C1-19 to 22 inches; olive brown (2.5Y 4/4) extremely

gravelly loamy sand, light olive brown (2.5Y 5/4) dry;

massive; soft, very friable, nonsticky and nonplastic;

weakly smeary; very few very fine roots; common very

fine irregular pores; about 50 percent pebbles and 20

percent cobbles; NaF pH 12.0; moderately acid; abrupt

wavy boundary.

C2-22 to 60 inches; olive brown (2.5Y 4/4) extremely

gravelly loamy sand, light yellowish brown (2.5Y 6/4)

dry; single grain; soft, very friable, nonsticky and

nonplastic; very few very fine roots; many very fine and

fine irregular pores; about 50 percent pebbles and 20

percent cobbles; NaF pH 12.0; moderately acid.

The thickness of the solum is 10 to 25 inches. The depth

to bedrock and the thickness of the part of the profile

influenced by volcanic ash are more than 60 inches. The

content of rock fragments in the control section ranges

from 40 to 60 percent pebbles and 10 to 20 percent

cobbles.

The E horizon has value of 5 or 6 when moist and 6 or

7 when dry and chroma of 2 to 4 when moist and dry.

The Bhs1 horizon has chroma of 4 to 6 when moist and

6 to 8 when dry. It is gravelly loam or gravelly silt loam.

The organic stains have value of 2 or 3 when moist and 3

or 4 when dry and chroma of 1 or 2 when moist and 2 to 4

when dry. The Bhs2 horizon has value of 3 or 4 when

moist and 4 or 5 when dry and chroma of 4 to 6 when

moist and dry. It is very gravelly loam or very gravelly fine

sandy loam.

The Bs horizon has chroma of 4 to 6 when moist and

dry. It is very gravelly sandy loam or very gravelly fine

sandy loam.

The C horizon has hue of 10YR or 2.5Y, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist and dry. It is very gravelly or extremely

gravelly loamy sand or very gravelly or extremely gravelly

sand.

Jug Series

The Jug series consists of very deep, somewhat

excessively drained soils formed in a mixture of volcanic

ash and glacial outwash over glacial outwash. These soils

are on outwash terraces. Slopes are 3 to 15 percent. The

average annual precipitation is 70 to 80 inches, and the

mean annual air temperature is about 44 degrees F.

These soils are sandy-skeletal, mixed, frigid Humic

Haplorthods.

Typical pedon of Jug very gravelly loam, 3 to 15

percent slopes, 10 miles east of Van Zandt, 800 feet

south and 2,200 feet east of the northwest corner of

sec. 26, T. 38 N., R. 6 E.

Oi-5 to 4 inches; undecomposed needles, leaves, and

twigs.

Oa-4 inches to 0; decomposed needles, leaves, and

twigs; many very fine, fine, medium, and coarse

roots.

E-0 to 2 inches; dark brown (7.5YR 4/2) very gravelly

loam, pinkish gray (7.5YR 7/2) dry; weak fine

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; many very

fine, fine, medium, and coarse roots; common fine

irregular pores; about 40 percent pebbles; NaF
pH 10.0; very strongly acid; abrupt smooth

boundary.

Bhs-2 to 6 inches; dark brown (7.5YR 4/4) very gravelly

loam, strong brown (7.5YR 5/6) dry; dark reddish

brown (5YR 3/3) organic stains, dark reddish brown

(5YR 3/4) dry; weak fine subangular blocky structure;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; common very fine, fine, and medium and few

coarse roots; common fine irregular pores; about 50

percent pebbles; NaF pH 11.5; very strongly acid;

abrupt smooth boundary.

Bs-6 to 9 inches; strong brown (7.5YR 5/6) very gravelly

loam, reddish yellow (7.5YR 6/6) dry; weak fine

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; common very

fine, fine, and medium and few coarse roots; about 50

percent pebbles; NaF pH 11.5; strongly acid; clear

wavy boundary.

BC-9 to 25 inches; yellowish brown (10YR 5/4) very

gravelly sandy loam, very pale brown (10YR 7/4) dry;

massive; slightly hard, friable, nonsticky and

nonplastic; weakly smeary; few fine and medium roots;

many fine irregular pores; about 60 percent pebbles;

NaF pH 10.5; moderately acid; clear wavy boundary.

2C-25 to 60 inches; olive brown (2.5Y 4/4) very gravelly

loamy sand, pale yellow (2.5Y 7/4) and yellow (2.5Y

7/6) dry; single grain; loose; many fine irregular pores;

about 60 percent pebbles; NaF pH 10.5; moderately

acid.

The thickness of the solum and of the part of the profile

influenced by volcanic ash is 14 to 30 inches. By weighted

average, the upper part of the particle-size control section

has 40 to 60 percent pebbles and 0 to 10 percent cobbles

and the lower part has 45 to 75 percent pebbles and 0 to

10 percent cobbles.

The E horizon has hue of 5YR or 7.5YR, value of 4 or

5 when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs horizon has hue of 5YR or 7.5YR, value of 3

or 4 when moist and 5 or 6 when dry, and chroma of 4 to

6 when moist and dry. It is very gravelly loam or very

gravelly sandy loam.

The Bs and BC horizons have hue of 7.5YR or 10YR,

value of 4 or 5 when moist and 6 or 7 when dry, and

chroma of 4 to 6 when moist and dry. They are very

gravelly loam or very gravelly sandy loam.

The 2C horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 4 to 6

when moist and dry. It is very gravelly loamy sand, very

gravelly sand, extremely gravelly loamy sand, or extremely

gravelly sand.

Kickerville Series

The Kickerville series consists of very deep, well

drained soils formed in a mixture of loess and volcanic

ash over glacial outwash. These soils are on outwash

terraces. Slopes are 0 to 15 percent. The average annual

precipitation is 35 to 55 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are coarse-loamy, mixed, mesic Typic

Haplorthods.

Typical pedon of Kickerville silt loam, 0 to 3 percent

slopes, 4 miles northeast of Lynden, 50 feet north and

700 feet east of the southwest corner of sec. 2, T. 40 N.,

R. 3 E.

Ap-0 to 9 inches; dark brown (10YR 3/3) silt loam,

yellowish brown (10YR 5/4) dry; weak fine granular

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; many very fine roots; many very fine

irregular pores; about 5 percent pebbles; NaF pH 11.5;

moderately acid; abrupt smooth boundary.

Bs1-9 to 22 inches; dark yellowish brown (10YR 3/4) silt loam,

light yellowish brown (10YR 6/4) dry; weak fine and

medium subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common very

fine roots; many very fine irregular pores; about 5

percent pebbles; NaF pH 12.0; moderately acid; abrupt

smooth boundary.

2Bs2-22 to 32 inches; dark yellowish brown (10YR 4/4)

very gravelly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; few very fine

roots; many very fine irregular pores; about 40 percent

pebbles and 5 percent cobbles; NaF pH 12.0; slightly

acid; abrupt smooth boundary.

3C1-32 to 42 inches; extremely gravelly sand that is

dominantly olive brown (2.5Y 4/4) and dark grayish

brown (2.5Y 4/2) but is variegated; light yellowish

brown (2.5Y 6/4) and light brownish gray (2.5Y 6/2)

dry; single grain; loose; many very fine irregular

pores; about 60 percent pebbles; NaF pH 12.0;

slightly acid; clear smooth boundary.

3C2-42 to 60 inches; very gravelly sand that is

dominantly dark grayish brown (2.5Y 4/2) but is

variegated; dark grayish brown (2.5Y 4/2) and

grayish brown (2.5Y 5/2) dry; single grain; loose;

many very fine irregular pores; about 50 percent

pebbles; NaF pH 11.5; neutral.

The upper 14 to 24 inches of the soil is essentially

nongravelly. Depth to the 2C horizon is 20 to 36 inches.
The content of rock fragments increases with increasing

depth. It ranges from 0 to 10 percent pebbles in the upper

part of the solum and from 35 to 65 percent pebbles and 0

to 5 percent cobbles in the lower part of the solum and

substratum. By weighted average, the content of rock

fragments in the particle-size control section is 25 to 35

percent.

The A horizon has hue of 7.5YR or 10YR, value of 2 or 3

when moist and 4 or 5 when dry, and chroma of 2 or 3

when moist and dry.

The Bs1 horizon has hue of 7.5YR or 10YR, value of 3

or 4 when moist and 4 to 6 when dry, and chroma of 4 to 6

when moist and dry. It is loam or silt loam. The content of

rock fragments ranges from 0 to 10 percent. The 2Bs2

horizon has value of 5 or 6 when dry and chroma of 3 or 4

when moist and dry. It is very gravelly loam, extremely

gravelly loam, very gravelly silt loam, or very gravelly sandy

loam.

The 3C horizon is variegated but has general hue of

10YR or 2.5Y, value of 3 or 4 when moist and 4 to 6 when

dry, and chroma of 2 to 4 when moist and dry. It is very

gravelly loamy sand, extremely gravelly sand, or very

gravelly sand.

Kindy Series

The Kindy series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash, loess, and colluvium over glacial till. These

soils are on high mountain back slopes and plateaus.

Slopes are 8 to 60 percent. The average annual

precipitation is 70 to 90 inches, and the mean annual air

temperature is about 43 degrees F.

These soils are loamy-skeletal, mixed, ortstein Typic

Cryorthods.

Typical pedon of Kindy gravelly silt loam, 30 to 60

percent slopes, 5 miles southeast of Acme, 2,400 feet

south and 1,900 feet east of the northwest corner of sec.

18, T. 37 N., R. 6 E.

Oi-6 inches to 1 inch; undecomposed needles, leaves,

and twigs.

Oa-1 inch to 0; decomposed forest litter; many very

fine, fine, and medium roots.

E-0 to 2 inches; brown (7.5YR 5/2) gravelly silt loam,

pinkish gray (7.5YR 7/2) dry; massive; soft, friable,

nonsticky and nonplastic; common very fine and many

fine roots; many very fine irregular pores; about 30

percent pebbles; very strongly acid; abrupt smooth

boundary.

Bhs-2 to 4 inches; strong brown (7.5YR 4/6) gravelly silt

loam, strong brown (7.5YR 5/6) dry; dark brown

(7.5YR 3/4) organic stains, brown (7.5YR 5/4) dry;

weak medium subangular blocky structure; slightly

hard, firm, nonsticky and nonplastic; weakly smeary;

common fine and few medium roots; many very fine

irregular pores; about 30 percent pebbles; NaF pH 10.5;

strongly acid; clear wavy boundary.

Bs-4 to 11 inches; brown (7.5YR 5/4) very gravelly silt

loam, pink (7.5YR 7/4) dry; weak fine subangular

blocky structure; slightly hard, friable, nonsticky and

nonplastic; weakly smeary; common very fine and fine

roots; many very fine irregular pores; about 40 percent

pebbles; NaF pH 12.0; moderately acid; clear smooth

boundary.

BC-11 to 25 inches; yellowish brown (10YR 5/6) very

gravelly loam, very pale brown (10YR 7/4) dry; weak

fine subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; many very

fine irregular pores; about 50 percent pebbles; NaF pH

12.0; moderately acid; abrupt smooth boundary.

2Cd-25 to 60 inches; pale brown (10YR 6/3), dense

glacial till that breaks to very gravelly loam, very pale

brown (10YR 7/3) dry; massive; hard, firm, nonsticky

and nonplastic; weakly smeary; about 40 percent

pebbles; NaF pH 10.5; slightly acid.

The depth to dense, compact glacial till and the

thickness of the part of the profile influenced by volcanic

ash range from 20 to 40 inches. The content of rock

fragments in the control section ranges from 35 to 60

percent.

The E horizon has hue of 7.5YR or 10YR and value of 4

to 6 when moist and 6 or 7 when dry.

The Bhs and Bs horizons have hue of 7.5YR or

10YR, value of 3 to 5 when moist and 4 to 7 when dry, and

chroma of 4 to 6 when moist and dry. They are gravelly

silt loam, gravelly loam, very gravelly silt loam, or very

gravelly loam.

The 2Cd horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 3 to 6

when moist and dry. It is dense glacial till that breaks to

very gravelly loam or very gravelly silt loam.

Klawatti Series

The Klawatti series consists of moderately deep, well

drained soils formed in volcanic ash, colluvium, and slope

alluvium derived from dunite and serpentine. These soils

are on high mountain shoulder slopes and ridgetops.

Slopes are 30 to 60 percent. The average annual

precipitation is 85 to 105 inches, and the mean annual air

temperature is about 41 degrees F.

These soils are loamy-skeletal, serpentinitic Typic

Cryorthods.

Typical pedon of Klawatti very gravelly loam, 30 to 60

percent slopes, 10 miles southeast of Van Zandt,
2,300 feet south and 400 feet west of the northeast

corner of sec. 34, T. 38 N., R. 6 E.

Oi-7 to 5 inches; undecomposed needles, twigs, and

bark.

Oa-5 inches to 0; decomposed organic mat; many very

fine, fine, medium, and coarse roots; about 20 percent

pebbles.

E-0 to 0.5 inch; dark gray (5YR 4/1) gravelly silt loam,

light gray (5YR 7/1) dry; massive; slightly hard, friable,

nonsticky and nonplastic; many very fine and fine and

common medium roots; many very fine irregular pores;

about 25 percent pebbles; NaF pH 10.0; extremely

acid; abrupt smooth boundary.

Bs1-0.5 inch to 2 inches; dark reddish brown (5YR

3/3) very gravelly loam, reddish brown (5YR 5/3)

dry; weak fine subangular blocky structure; soft,

very friable, nonsticky and nonplastic; weakly

smeary; many fine and common medium roots;

many very fine irregular pores; about 30 percent

pebbles and 10 percent cobbles; NaF pH 11.0;

strongly acid; clear wavy boundary.

Bs2-2 to 10 inches; dark yellowish brown (10YR 4/4)

extremely gravelly silt loam, light yellowish brown

(10YR 6/4) dry; weak fine subangular blocky structure;

soft, very friable, nonsticky and nonplastic; weakly

smeary; many fine and medium roots; many very fine

irregular pores; about 45 percent pebbles and 20

percent cobbles; NaF pH 11.0; slightly acid; clear

wavy boundary.

Bs3-10 to 25 inches; dark yellowish brown (10YR 3/4)

extremely gravelly silt loam, light yellowish brown

(10YR 6/4) dry; weak fine and medium subangular

blocky structure; soft, friable, nonsticky and nonplastic;

weakly smeary; common fine and many medium and

coarse roots; many very fine irregular pores; about 40

percent pebbles, 20 percent cobbles, and 5 percent

stones; NaF pH 11.0; slightly acid; abrupt wavy

boundary.

2R-25 inches; dunite.

The depth to dunite or serpentine and the thickness of

the part of the profile influenced by volcanic ash are 20 to

40 inches. The content of rock fragments in the control

section ranges from 40 to 70 percent.

The E horizon has hue of 5YR or 7.5YR, value of 3 to

5 when moist and 4 to 7 when dry, and chroma of 1 or 2

when moist and dry.

The Bs1 horizon has hue of 2.5YR to 7.5YR, value of 3

or 4 when moist and 5 or 6 when dry, and chroma of 3 or 4

when moist and dry. It is very gravelly loam, very gravelly

silt loam, or extremely gravelly silt loam.

The Bs2 and Bs3 horizons have hue of 7.5YR or

10YR, value of 3 or 4 when moist and 5 or 6 when dry,

and chroma of 3 to 6 when moist and dry. They are very

gravelly loam, very gravelly silt loam, or extremely gravelly

silt loam.

Kline Series

The Kline series consists of very deep, moderately well

drained soils formed in alluvium. These soils are on alluvial

fans. Slopes are 2 to 8 percent. The average annual

precipitation is 40 to 70 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are sandy-skeletal, mixed, mesic Aquic

Xerofluvents.

Typical pedon of Kline gravelly sandy loam, 2 to 8

percent slopes, 1.5 miles northwest of Deming, 1,300 feet

north and 1,400 feet east of the southwest corner of sec.

25, T. 39 N., R. 4 E.

Ap-0 to 4 inches; dark brown (10YR 3/3) gravelly sandy

loam, pale brown (10YR 6/3) dry; weak medium

granular structure; slightly hard, friable, nonsticky and

nonplastic; many very fine roots; many very fine

irregular pores; about 30 percent pebbles; moderately

acid; abrupt smooth boundary.

C1-4 to 9 inches; olive brown (2.5Y 4/4) gravelly

sandy loam, light olive brown (2.5Y 5/4) dry;

massive; slightly hard, friable, nonsticky and

nonplastic; many very fine roots; many very fine

irregular pores; about 20 percent pebbles;

moderately acid; abrupt smooth boundary.

2C2-9 to 20 inches; dark brown (10YR 3/3) extremely

gravelly loamy sand, brown (10YR 5/3) dry; single

grain; loose; many very fine roots; many very fine

irregular pores; about 70 percent pebbles; moderately

acid; abrupt smooth boundary.

2C3-20 to 29 inches; dark grayish brown (2.5Y 4/2) very

gravelly loamy sand, light brownish gray (2.5Y 6/2)

dry; single grain; loose; common very fine roots; many

very fine irregular pores; about 60 percent pebbles;

slightly acid; clear smooth boundary.

2C4-29 to 60 inches; dark grayish brown (2.5Y 4/2) very

gravelly sand, light yellowish brown (2.5Y 6/3) dry;

single grain; loose; very few very fine roots; many fine

irregular pores; about 60 percent pebbles; strata of

very gravelly sandy loam at 30 to 31 inches and at 47

to 48 inches; slightly acid.

The depth to the 2C horizon ranges from 8 to 20

inches. The content of rock fragments in the control

section ranges from 45 to 75 percent.

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 2 to 4

when moist and dry.

The C1 horizon has hue of 10YR or 2.5Y and value
of 4 or 5 when moist and 5 or 6 when dry. It is gravelly or

very gravelly loam or gravelly or very gravelly sandy loam.

Some pedons have a weakly developed B horizon and do

not have a C horizon.

The 2C horizon has hue of 10YR or 2.5Y, value of 3 to

5 when moist and 5 or 6 when dry, and chroma of 2 to 4

when moist and dry. It is very gravelly sand, very gravelly

loamy sand, or extremely gravelly loamy sand that has thin

strata of sandy loam or very fine sandy loam. Some

pedons have strata of sandy loam or very fine sandy loam

below the control section. These strata are 10 to 30 inches

thick.

Kulshan Series

The Kulshan series consists of moderately deep, well

drained soils formed in volcanic ash, loess, and colluvium

and slope alluvium derived from sandstone and

metasedimentary rocks. These soils are on mountain back

slopes and ridges. Slopes are 5 to 80 percent. The

average annual precipitation is 90 to 110 inches, and the

mean annual air temperature is about 40 degrees F.

These soils are coarse-loamy, mixed Humic

Cryorthods.

Typical pedon of Kulshan loam, 30 to 60 percent

slopes, 7 miles southwest of Glacier, 1,500 feet south and

2,500 feet east of the northwest corner of sec. 33, T. 39

N., R. 6 E.

Oi-7 to 2 inches; undecomposed needles, twigs, bark,

leaves, and moss.

Oa-2 inches to 0; decomposed needles, twigs, and

leaves; many very fine, fine, medium, and coarse

roots.

E-0 to 3 inches; dark brown (7.5YR 4/2) fine sandy

loam, brown (7.5YR 5/2) dry; massive; soft, very

friable, nonsticky and nonplastic; many very fine, fine,

medium, and coarse roots; common very fine

irregular pores; about 5 percent pebbles; NaF pH

9.0; very strongly acid; abrupt smooth boundary.

Bhs1-3 to 8 inches; dark red (2.5YR 3/6) loam, yellowish

red (5YR 5/6) dry; black (5YR 2/1) stains on 60

percent of soil matrix, dark reddish brown (5YR 3/3)

dry; moderate medium subangular blocky structure;

hard, firm, nonsticky and nonplastic; weakly smeary;

common very fine, fine, and medium and few coarse

roots; common very fine irregular pores; about 5

percent unweathered pebbles and 10 percent

weathered pebbles; NaF pH 11.0; strongly acid; clear

irregular boundary.

Bhs2-8 to 14 inches; yellowish red (5YR 4/6) gravelly

loam, reddish yellow (7.5YR 6/6) dry; very dusky red

(2.5YR 2/2) organic stains on faces of peds,

dark reddish brown (2.5YR 3/4) dry; moderate medium

subangular blocky structure; hard, firm, nonsticky and

nonplastic; weakly smeary; common very fine and fine

roots; common very fine irregular pores; about 15

percent unweathered pebbles, 10 percent weathered

pebbles, and 5 percent unweathered cobbles; NaF pH

12.0; strongly acid; clear wavy boundary.

Bs1-14 to 23 inches; yellowish red (5YR 5/6) cobbly fine

sandy loam, reddish yellow (2.5YR 6/6) dry; weak

medium subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common very

fine and fine roots; common very fine irregular pores;

about 10 percent unweathered cobbles, 25 percent

weathered pebbles, and 10 percent unweathered

cobbles; NaF pH 12.0; strongly acid; clear smooth

boundary.

Bs2-23 to 30 inches; dark reddish brown (5YR 3/4)

gravelly loam, reddish brown (5YR 4/4) dry; weak

coarse subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; few fine

roots; common very fine irregular pores; about 20

percent unweathered pebbles, 20 percent weathered

pebbles, and 10 percent unweathered cobbles; NaF pH

12.0; strongly acid; abrupt smooth boundary.

2R-30 inches; hard sandstone.

The depth to sandstone and the thickness of the part of

the profile influenced by volcanic ash are 20 to 40 inches.

The content of rock fragments in the control section ranges

from 5 to 25 percent unweathered pebbles, 15 to 35

percent weathered pebbles, and 0 to 10 percent

unweathered cobbles.

The E horizon has hue of 7.5YR or 10YR, value of 4 or

5 when moist and 5 to 8 when dry, and chroma of 2 or 3

when moist and 1 or 2 when dry.

The Bhs horizon has hue of 2.5YR to 7.5YR, value of 3

or 4 when moist and 3 to 5 when dry, and chroma of 2 to 6

when moist and dry. It is loam, gravelly loam, or silt loam.

The Bs horizon has hue of 5YR to 10YR, value of 3 to 5

when moist and 4 to 6 when dry, and chroma of 2 to 6

when moist and dry. It is very gravelly loam, very gravelly

fine sandy loam, or very gravelly sandy loam.

Some pedons have a C horizon.

Labounty Series

The Labounty series consists of very deep, poorly

drained soils formed in glaciomarine drift with an admixture

of loess and volcanic ash. These soils are on glaciomarine

drift plains and in depressional positions on the kame-kettle

topography. Slopes are 0 to 2
percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are fine-loamy, mixed, mesic Typic

Umbraqualfs.

Typical pedon of Labounty silt loam, in an area of

Whatcom-Labounty silt loams, 0 to 8 percent slopes; 7

miles northeast of Bellingham, 20 feet north and 500 feet

east of the southwest corner of sec. 30, T. 39 N., R. 4 E.

Ap-0 to 10 inches; very dark grayish brown (10YR 3/2) silt

loam, grayish brown (10YR 5/2) dry; weak fine granular

structure; slightly hard, friable, slightly sticky and

nonplastic; many very fine and fine roots; many very

fine irregular pores; about 5 percent pebbles; NaF pH

10.2; moderately acid; abrupt smooth boundary.

Eg1-10 to 13 inches; grayish brown (2.5Y 5/2) loam,

white (2.5Y 8/2) dry; many coarse prominent yellowish

brown (10YR 5/6) mottles, brownish yellow (10YR 6/6)

dry; moderate medium subangular blocky structure;

slightly hard, friable, slightly sticky and slightly plastic;

many very fine roots; many very fine irregular pores;

about 5 percent pebbles; NaF pH 9.4; moderately acid;

clear smooth boundary.

Eg2-13 to 16 inches; light brownish gray (2.5Y 6/2) loam,

light gray (2.5Y 7/2) and white (2.5Y 8/2) dry; many

coarse prominent yellowish brown (10YR 5/6) mottles,

brownish yellow (10YR 6/6) dry; moderate medium

subangular blocky structure; slightly hard, friable, slightly

sticky and slightly plastic; common very fine roots; many

very fine irregular pores; about 5 percent pebbles;

moderately acid; clear smooth boundary.

Eg3-16 to 22 inches; light olive gray (5Y 6/2) loam,

white (5Y 8/2) dry; many coarse prominent yellowish

brown (10YR 5/6) mottles, brownish yellow (10YR 6/6)

dry; weak medium subangular blocky structure; slightly

hard, friable, slightly sticky and slightly plastic; common

very fine roots; common very fine irregular pores; about

10 percent pebbles; neutral; clear smooth boundary.

Btg1-22 to 28 inches; grayish brown (2.5Y 5/2) and olive

gray (5Y 5/2) loam, light gray (2.5Y 7/2) and white (5Y

8/2) dry; many coarse prominent yellowish brown

(10YR 5/6) mottles, brownish yellow (10YR 6/6 and

6/8) dry; moderate thick platy structure; very hard, firm,

slightly sticky and plastic; common very fine roots;

common very fine irregular pores; few thin patchy clay

films on faces of peds; about 5 percent pebbles;

neutral; clear smooth boundary.

Btg2-28 to 35 inches; olive gray (5Y 5/2) and light olive

gray (5Y 6/2) loam, light gray (5Y 7/2) dry; many

coarse prominent yellowish brown (10YR 5/6) mottles,

brownish yellow (10YR 6/6) dry; moderate thick platy

structure; very hard, firm, slightly sticky and plastic;

few very fine roots; few thin patchy clay films on faces

of peds; common very fine irregular pores; about 5

percent pebbles; neutral; abrupt smooth boundary.

Cg-35 to 60 inches; gray (5Y 5/1) loam, light gray (5Y

6/1) dry; moderate medium blocky structure; extremely

hard, very firm, slightly sticky and slightly plastic; very

few very fine irregular pores; about 5 percent pebbles;

neutral.

The thickness of the solum is 20 to 40 inches. By

weighted average, the control section has 18 to 35

percent clay and 0 to 10 percent pebbles, although

individual horizons contain 0 to 25 percent pebbles.

The A horizon has hue of 7.5YR or 10YR, value of 2 or 3

when moist and 4 or 5 when dry, and chroma of 2 or 3

when moist and dry.

The Eg horizon has hue of 10YR or 2.5Y and value of 4

to 6 when moist and 6 to 8 when dry. It is loam or silt

loam.

The Btg horizon has hue of 10YR to 5Y, value of 4 to 6

when moist and 6 to 8 when dry, and chroma of 2 or 3

when moist and dry. It is loam, clay loam, or silty clay

loam. It is weak or moderate and platy or subangular

blocky, or it is massive.

The Cg horizon has hue of 2.5Y or 5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry. It is loam, clay loam, or silty clay

loam.

Larush Series

The Larush series consists of very deep, well drained

soils formed in alluvium. These soils are on low river

terraces. Slopes are 0 to 2 percent. The average annual

precipitation is 60 to 70 inches, and the mean annual air

temperature is about 49 degrees F.

These soils are coarse-silty over sandy or sandyskeletal, mixed, mesic Fluventic Xerumbrepts.

Typical pedon of Larush silt loam, 0 to 2 percent slopes,

0.5 mile east of Acme, 500 feet south and 2,100 feet west

of the northeast corner of sec. 8, T. 37 N., R. 5 E.

Ap-0 to 7 inches; very dark grayish brown (2.5Y 3/2) silt

loam, grayish brown (2.5Y 5/2) dry; weak coarse

granular structure; slightly hard, friable, nonsticky and

nonplastic; many very fine and few fine roots;
many very fine irregular pores; slightly acid; clear

smooth boundary.

C1-7 to 17 inches; very dark grayish brown (2.5Y 3.2) silt

loam, light brownish gray (2.5Y 6/2) dry; massive;

slightly hard, friable, nonsticky and nonplastic; many

very fine roots; many very fine irregular pores; slightly

acid; clear smooth boundary.

C2-17 to 25 inches; dark grayish brown (2.5Y 4/2) silt

loam, light brownish gray (2.5Y 6/2) dry; massive;

slightly hard, friable, nonsticky and nonplastic; few very

fine roots; many very fine irregular pores; slightly acid;

clear smooth boundary.

2C3-25 to 31 inches; dark grayish brown (2.5Y 4/2)

stratified fine sand and sand, light brownish gray (2.5Y

6/2) dry; massive; soft, friable, nonsticky and

nonplastic; thin strata of silt loam; very few very fine

roots; many very fine irregular pores; slightly acid;

clear smooth boundary.

2C4-31 to 50 inches; dark grayish brown (2.5Y 4/2)

fine sand, light brownish gray (2.5Y 6/2) dry;

massive; loose, friable, nonsticky and nonplastic;

thin strata of silt loam; very few very fine roots;

many fine irregular pores; slightly acid; abrupt

smooth boundary.

2C5-50 to 60 inches; dark grayish brown (2.5Y 4/2)

sand, brownish gray (2.5Y 5/2) dry; single grain;

loose; many fine irregular pores; slightly acid.

The thickness of the solum ranges from 15 to 30 inches.

The solum has 5 to 10 percent clay and 0 to 15 percent

sand coarser than very fine sand.

The A horizon has hue to 10YR or 2.5Y and value of 4 or

5 when dry. The C horizon has hue of 10YR or 2.5Y and

value of 3 or 4 when moist and 5 or 6 when dry. It is silt

loam or very fine sandy loam. Some pedons have a B

horizon. The 2C horizon has value of 5 or 6 when dry. It is

loamy fine sand, fine sand, or sand.

Laxton Series

The Laxton series consists of very deep, moderately well

drained soils formed in volcanic ash and loess over glacial

outwash. These soils are on outwash terraces. Slopes are

0 to 15 percent. The average annual precipitation is 35 to

55 inches, and the mean annual air temperature is about

50 degrees F.

These soils are coarse-loamy over sandy or sandyskeletal, mixed, mesic Aquic Haplorthods.

Typical pedon of Laxton loam, 0 to 3 percent slopes, 7

miles southeast of Blaine, 1,400 feet north and 400 feet

east of the southwest corner of sec. 7, T. 40 N., R. 2 E.

Ap-0 to 9 inches; dark yellowish brown (10YR 3/4) loam,

yellowish brown (10YR 5/4) dry; weak fine subangular

blocky structure parting to weak fine granular; soft, very

friable, nonsticky and nonplastic; weakly smeary; many

very fine and fine roots; many very fine irregular pores;

NaF pH 10.5; slightly acid; clear smooth boundary.

Bs1-9 to 17 inches; dark brown (7.5YR 4/4) silt loam,

light yellowish brown (10YR 6/4) dry; moderate

medium subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine and common fine roots; many very fine irregular

pores; NaF pH 12.0; moderately acid; abrupt wavy

boundary.

Bs2-17 to 23 inches; dark yellowish brown (10YR 4/4) silt

loam, light yellowish brown (10YR 6/4) dry; weak

medium subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine and common fine roots; many very fine irregular

pores; NaF pH 12.0; moderately acid; abrupt wavy

boundary.

2CB-23 to 32 inches; olive brown (2.5Y 4/4) loamy sand,

pale yellow (2.5Y 7/4) dry; few fine prominent strong

brown (7.5YR 4/6) mottles, reddish yellow (7.5YR 6/6)

dry; weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary; many

very fine and common fine roots; many very fine

irregular pores; NaF pH 11.5; moderately acid; clear

wavy boundary.

2C1-32 to 43 inches; sand that is dominantly olive brown

(2.5Y 4/4) but is variegated; light yellowish brown

(2.5Y 6/4) dry; common coarse prominent yellowish

brown (10YR 5/6) mottles, brownish yellow (10YR 6/6)

dry; single grain; loose; common very fine roots; many

very fine irregular pores; moderately acid; abrupt wavy

boundary.

2C2-43 to 55 inches; sand that is dominantly light

brownish gray (2.5Y 6/2) but is variegated; light gray

(2.5Y 7/2) dry; common medium prominent dark

yellowish brown (10YR 4/6) mottles, brownish yellow

(10YR 6/6) dry; some dark yellowish brown (10YR 4/6)

bands 1 to 2 millimeters thick; massive; soft, very

friable, nonsticky and nonplastic; very few very fine

roots; many very fine irregular pores; slightly acid;

abrupt smooth boundary.

3C3-55 to 57 inches; dark yellowish brown (10YR 4/6)

loamy sand, brownish yellow (10YR 6/6) dry; many fine

distinct yellowish red (5YR 5/6) mottles, reddish yellow

(5YR 6/6) dry; massive; slightly hard, very friable,

nonsticky and nonplastic; very few very fine roots;

many very fine irregular pores; slightly acid; abrupt

smooth boundary.

4C4-57 to 60 inches; sand that is dominantly dark
grayish brown (2.5Y 4/2) but is variegated; light

brownish gray (2.5Y 6/2) dry; single grain; loose;

many very fine irregular pores; slightly acid.

The thickness of the solum and of the part of the profile

influenced by volcanic ash is 20 to 40 inches. The lower

part of the particle-size control section has 0 to 15 percent

fine pebbles by weighted average. Mottles are below a

depth of 20 inches. They are below a depth of 30 inches if

chroma is 2 or less.

The A horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 4 or 5 when dry, and chroma of 2 to 4

when moist and dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 4

or 5 when moist and 5 or 6 when dry, and chroma of 3 to

6 when moist and dry. It is silt loam, loam, or fine sandy

loam.

The 2CB horizon has hue of 10YR or 2.5Y, value of 3 to

5 when moist and 6 or 7 when dry, and chroma of 3 or 4

when moist and dry. It has mottles with hue of 7.5YR or

10YR, value of 4 or 5 when moist, and chroma of 4 to 6

when moist and dry. It is loamy sand or loamy fine sand.

The 2C horizon is variegated but has hue of 10YR or

2.5Y, value of 4 or 5 when moist and 6 or 7 when dry, and

chroma of 2 to 4 when moist and dry. It has mottles with

hue of 7.5YR or 10YR, value of 4 or 5 when moist and 5 or

6 when dry, and chroma of 2 to 6 when moist and dry.

Either the matrix or the mottles have chroma of 2 or less in

some part of the horizon. The 2C horizon is sand, fine

sand, or loamy sand.

Lynden Series

The Lynden series consists of very deep, well drained

soils formed in volcanic ash and loess over glacial

outwash. These soils are on outwash terraces. Slopes

are 0 to 8 percent. The average annual precipitation is

40 to 55 inches, and the mean annual air temperature is

about 50 degrees F.

These soils are sandy, mixed, mesic Typic

Haplorthods.

Typical pedon of Lynden sandy loam, 3 to 8 percent

slopes, 6 miles south of Lynden, 900 feet north and 750

feet east of the southwest corner of sec. 16, T. 39 N., R. 3

E.

Ap-0 to 8 inches; dark brown (7.5YR 3/2) sandy loam,

dark brown (10YR 4/3) dry; weak fine granular structure;

soft, very friable, nonsticky and nonplastic; weakly

smeary; many very fine roots; many very fine irregular

pores; NaF pH 11.0; moderately acid; abrupt smooth

boundary.

Bs-8 to 18 inches; dark brown (7.5YR 4/4) sandy

loam, light yellowish brown (10YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine roots; many very fine irregular pores; NaF pH 12.0;

slightly acid; abrupt smooth boundary.

2CBs-18 to 30 inches; very dark grayish brown (2.5Y 3/3)

sand, pale brown (10YR 6/3) dry; single grain; loose;

many very fine roots; many fine irregular pores; NaF

pH 10.5; slightly acid; clear smooth boundary.

2C-30 to 60 inches; sand that is dominantly dark grayish

brown (2.5Y 4/2) but is variegated; grayish brown

(10YR 5/2) dry; single grain; loose; many fine irregular

pores; slightly acid.

The thickness of the part of the profile influenced by

volcanic ash and the depth to the 2CB horizon are 14 to 24

inches. The content of fine pebbles in the control section

ranges from 0 to 15 percent.

The A horizon has hue of 7.5Y or 10YR and value of 3 or

4 when moist and 4 to 6 when dry. Some pedons have an

E horizon.

The Bs horizon has hue of 7.5Y or 10YR and value of

4 or 5 when moist and 5 to 7 when dry.

The 2CBs horizon has hue of 10YR or 2.5Y, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 3 or 4

when moist and dry. It is loamy sand, sand, or coarse sand.

The C horizon has hue of 10YR or 2.5Y. It is loamy

sand, sand, or coarse sand.

Lynnwood Series

The Lynnwood series consists of very deep, somewhat

excessively drained soils formed in sandy glaciofluvial

deposits mixed with loess and volcanic ash. These soils are

on eskers and kames. Slopes are 0 to 20 percent. The

average annual precipitation is 35 to 55 inches, and the

mean annual air temperature is about 50 degrees F.

These soils are sandy, mixed, mesic Typic

Haplorthods.

Typical pedon of Lynnwood sandy loam, 0 to 5 percent

slopes, 4.5 miles southeast of Blaine, 600 feet north and

1,700 feet east of the southwest corner of sec. 15, T. 40

N., R. 1 E.

A-0 to 3 inches; very dark brown (10YR 2/2) sandy

loam, dark yellowish brown (10YR 4/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common

very fine, fine, and medium roots; many fine irregular

pores; NaF pH 10.0; strongly acid; abrupt wavy

boundary.
Bs1-3 to 5 inches; dark brown (7.5YR 3/2 and 3/4) sandy

loam, dark brown (7.5YR 4/4) and brown (7.5YR 5/4)

dry; weak medium subangular blocky structure; soft,

very friable, nonsticky and nonplastic; weakly smeary;

common very fine, fine, and medium roots; many fine

irregular pores; NaF pH 12.0; strongly acid; clear wavy

boundary.

Bs2-5 to 12 inches; dark yellowish brown (10YR 3/4 and

3/6) loamy sand, yellowish brown (10YR 5/4 and 5/6)

dry; weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; common very fine,

fine, and medium roots; many fine irregular pores; NaF

pH 12.0; moderately acid; abrupt smooth boundary.

BC-12 to 19 inches; dark yellowish brown (10YR 3/6)

loamy sand, light olive brown (2.5Y 5/4) dry; weak

medium subangular blocky structure; loose, nonsticky

and nonplastic; common very fine and fine and few

medium and coarse roots; many fine irregular pores;

NaF pH 12.0; moderately acid; clear smooth boundary.

C1-19 to 32 inches; sand variegated with hue of 2.5Y;

single grain; loose; few fine roots; many fine irregular

pores; NaF pH 12.0; moderately acid; gradual smooth

boundary.

C2-32 to 60 inches; sand variegated with hue of 5Y;

single grain; loose; many fine irregular pores; NaF pH

12.0; moderately acid.

The thickness of the solum is 15 to 36 inches. The

content of rock fragments in the control section ranges

from 0 to 10 percent.

The A horizon has hue of 7.5YR or 10YR, value of 2 or 3

when moist and 3 or 4 when dry, and chroma of 1 to 4

when moist and dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 4 to 6 when dry, and chroma of 4 to 6

when moist and dry. It is dominantly loamy fine sand or

loamy sand. In some pedons, however, the upper 4 inches

is sandy loam.

The C horizon has hue of 10YR to 5Y. It is sand,

coarse sand, or gravelly sand. The content of rock

fragments ranges from 0 to 15 percent.

Montborne Series

The Montborne series consists of moderately deep,

moderately well drained soils formed in an admixture of

volcanic ash, loess, colluvium, and slope alluvium over

glacial till derived dominantly from phyllite. These soils are

on mountain back slopes and plateaus. Slopes are 5 to 60

percent. The average annual precipitation is 60 to 70

inches, and the mean annual air temperature is about 44

degrees F.

These soils are loamy-skeletal, mixed, frigid Typic

Haplorthods.

Typical pedon of Montborne gravelly loam, 5 to 30

percent slopes, 3 miles southeast of Van Zandt, 800 feet

south and 2,000 feet west of the northeast corner of sec.

27, T. 38 N., R. 5 E.

Oi-4 to 3 inches; undecomposed needles and twigs.

Oa-3 inches to 0; decomposed needles and twigs;

many very fine, fine, medium, and coarse roots.

E-0 to 2 inches; dark brown (10YR 3/3) loam, light gray

(10YR 7/2) dry; massive; soft, very friable, nonsticky and

nonplastic; weakly smeary; many very fine, fine,

medium, and coarse roots; many fine irregular pores;

about 15 percent weathered pebbles and 5 percent

hard pebbles; NaF pH 10.0; very strongly acid; abrupt

wavy boundary.

Bs1-2 to 7 inches; dark yellowish brown (10YR 3/6)

gravelly loam, yellowish brown (10YR 5/6) dry;

moderate fine and medium subangular blocky

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; common very fine and coarse and

many fine and medium roots; common very fine

irregular pores; about 25 percent pebbles and 5

percent cobbles; NaF pH 11.5; strongly acid; clear

wavy boundary.

Bs2-7 to 15 inches; dark yellowish brown (10YR 3/6) very

gravelly loam, brownish yellow (10YR 6/6) dry;

moderate fine and medium subangular blocky structure;

soft, very friable, nonsticky and nonplastic; weakly

smeary; NaF pH 11.0; about 40 percent pebbles and 5

percent cobbles; common fine and medium and few

coarse roots; common very fine irregular pores;

strongly acid; clear smooth boundary.

CB-15 to 33 inches; olive brown (2.5Y 4/4) extremely

gravelly sandy loam, pale yellow (2.5Y 7/4) dry;

massive; soft, very friable, nonsticky and nonplastic;

NaF pH 11.0; about 50 percent pebbles, 5 percent

channers, and 5 percent cobbles; few fine and medium

roots; common very fine irregular pores; moderately

acid; abrupt smooth boundary.

2Cd-33 to 60 inches; light olive brown (2.5Y 5/4), dense

glacial till that breaks to very gravelly loam, light gray

(2.5Y 7/2) dry; massive; hard, firm, nonsticky and

nonplastic; about 25 percent pebbles and 20 percent

channers; moderately acid.

The thickness of the solum is 14 to 24 inches. The

depth to dense, compact glacial till is 20 to 40 inches.

The content of hard phyllite rock fragments in the control

section ranges from 40 to 60 percent.

The E horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 2
or 3 when moist and dry. Some pedons have an A

horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 4 to 6 when dry, and chroma of 4 to 6

when moist and dry. It is very gravelly loam or very

gravelly silt loam.

The 2Cd horizon has hue of 2.5Y or 5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry. It is dense glacial till that breaks to

very gravelly loam or very gravelly sandy loam.

Mt. Vernon Series

The Mt. Vernon series consists of very deep, moderately

well drained soils formed in alluvium with an admixture of

volcanic ash in the upper part. These soils are on river

terraces and flood plains. Slopes are 0 to 2 percent. The

average annual precipitation is 30 to 50 inches, and the

mean annual air temperature is about 50 degrees F.

These soils are coarse-loamy, mixed, mesic

Fluvaquentic Haploxerolls.

Typical pedon of Mt. Vernon fine sandy loam, 0 to 2

percent slopes, 2 miles south of Ferndale, 750 feet north

and 250 feet west of the southeast corner of sec. 31, T.

39 N., R. 2 E.

Ap1-0 to 7 inches; dark brown (10YR 3/3) fine sandy

loam, grayish brown (2.5Y 5/2) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; common very fine roots;

many very fine irregular pores; moderately acid; clear

smooth boundary.

Ap2-7 to 13 inches; very dark grayish brown (2.5Y 3/2)

fine sandy loam, light brownish gray (2.5Y 6/2) dry;

weak fine subangular blocky structure; soft, very

friable, nonsticky and nonplastic; common very fine

roots; many very fine irregular pores; moderately acid;

clear smooth boundary.

C1-13 to 20 inches; dark grayish brown (2.5Y 4/2) and

olive brown (2.5Y 4/4), stratified fine sandy loam and

sand, light brownish gray (2.5Y 6/2) and light olive

brown (2.5Y 5/4) dry; many medium prominent

yellowish brown (10YR 5/8) mottles, brownish yellow

(10YR 6/8) dry; massive; soft, very friable, nonsticky

and nonplastic; very few very fine roots; many very fine

irregular pores; slightly acid; clear smooth boundary.

C2-20 to 31 inches; olive gray (5Y 4/2), stratified fine

sandy loam and sand, light brownish gray (2.5Y 6/2)

and light gray (5Y 7/1) dry; common medium prominent

yellowish brown (10YR 5/8) and strong brown (7.5YR

5/8) mottles, brownish yellow (10YR 6/8) dry; massive;

soft, very friable, nonsticky and

nonplastic; many very fine irregular pores; slightly

acid; clear smooth boundary.

C3-31 to 42 inches; olive gray (5Y 4/2), stratified very

fine sandy loam and fine sandy loam, gray (5Y 6/1)

dry; common medium prominent dark yellowish brown

(10YR 4/6) mottles, brownish yellow (10YR 6/6) dry;

massive; soft, very friable, nonsticky and nonplastic;

many fine irregular pores; neutral when moist, slightly

acid when dry; clear smooth boundary.

C4-42 to 60 inches; dark grayish brown (2.5Y 4/2) and

dark gray (5Y 4/1), stratified sand and very fine sandy

loam, light brownish gray (2.5Y 6/2) and gray (5Y 6/1)

dry; common medium prominent yellowish brown

(10YR 5/6) mottles, brownish yellow (10YR 6/6) dry;

massive; soft, friable, nonsticky or slightly sticky and

nonplastic; many fine irregular pores; neutral when

moist, slightly acid when dry.

The control section contains, by weighted average, 5 to

18 percent clay and 15 to 30 percent sand coarser than

very fine sand.

The Ap1 horizon has hue of 10YR or 2.5Y, value of 4 or

5 when dry, and chroma of 2 or 3 when moist and dry.

The Ap2 horizon has hue of 10YR or 2.5Y, value of 4 to 6

when dry, and chroma of 2 or 3 when moist and dry. It is

fine sandy loam or very fine sandy loam.

The C horizon has hue of 2.5Y or 5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry. It is stratified very fine sandy loam,

fine sandy loam, and sand. Reaction in the lower part of

the C horizon is 0 to 0.5 pH unit lower when dry than when

moist.

Nati Series

The Nati series consists of moderately deep, well

drained soils formed in colluvium and slope alluvium

derived from sandstone and siltstone with an admixture of

volcanic ash and glacial till. These soils are on foothill

back slopes and plateaus. Slopes are 5 to 60 percent. The

average annual precipitation is 35 to 50 inches, and the

mean annual air temperature is about 47 degrees F.

These soils are coarse-loamy, mixed, mesic Typic

Haplorthods.

Typical pedon of Nati loam, 15 to 30 percent slopes, 6

miles southeast of Bellingham, 400 feet north and 2,000

feet east of the southwest corner of sec. 12, T. 37 N., R.

4 E.

O1-3.5 to 3 inches; undecomposed needles, leaves,

and twigs.
O2-3 inches to 0; decomposed forest litter; many very

fine and fine roots.

A-0 to 8 inches; dark brown (10YR 3/3) loam, yellowish

brown (10YR 5/4) dry; weak fine and medium

subangular blocky structure; slightly hard, friable,

slightly sticky and nonplastic; weakly smeary; common

very fine and fine, many medium, and common coarse

roots; many fine irregular pores; about 5 percent

weathered pebbles; NaF pH 10.1; strongly acid; abrupt

smooth boundary.

Bs-8 to 16 inches; dark yellowish brown (10YR 4/4) loam,

light yellowish brown (10YR 6/4) dry; weak fine and

medium subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common very

fine, fine, and medium roots; many fine irregular pores;

about 30 percent weathered pebbles and 5 percent

hard, rounded pebbles; NaF pH 10.6; strongly acid;

abrupt smooth boundary.

BC-16 to 31 inches; brownish yellow (10YR 6/6) fine

sandy loam, pale yellow (2.5Y 7/4) dry; massive; soft,

very friable, nonsticky and nonplastic; weakly smeary;

few fine, medium, and coarse roots; many fine

irregular pores; about 35 percent weathered pebbles;

NaF pH 11.0; strongly acid; abrupt wavy boundary.

2Cr-31 inches; sandstone.

The depth to sandstone and the thickness of the part of

the profile influenced by volcanic ash are 20 to 40 inches.

The content of hard rock fragments in the particle-size

control section ranges from 5 to 20 percent and that of

weathered fragments ranges from 20 to 50 percent.

The A horizon has hue of 7.5YR or 10YR, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 2 to 6

when moist and 4 to 6 when dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 or 6 when dry, and chroma of 4 to 6

when moist and dry. It is loam or sandy loam.

The BC horizon has hue of 7.5YR to 2.5Y, value of 4 to

6 when moist and 6 or 7 when dry, and chroma of 4 to 6

when dry. It is loam, sandy loam, fine sandy loam, or

gravelly loam. Some pedons have a C horizon and do not

have a BC horizon.

Neptune Series

The Neptune series consists of very deep, somewhat

excessively drained soils formed in coastal beach deposits

that contain marine shells. These soils are on marine

ridges, spits, and terraces. Slopes are 0 to 3 percent. The

average annual precipitation is 30 to 40

inches, and the mean annual air temperature is 50

degrees F.

These soils are sandy-skeletal, mixed, mesic Entic

Haploxerolls.

Typical pedon of Neptune very gravelly sandy loam, 0

to 3 percent slopes, 1.5 miles west of Blaine on

Semiahmoo Spit, 3,200 feet east and 700 feet north of

the southwest corner of sec. 2, T. 40 N., R. 1 W.

A-0 to 10 inches; black (10YR 2/1) very gravelly sandy

loam, very dark grayish brown (10YR 3/2) dry; weak

very fine granular structure; soft, very friable, nonsticky

and nonplastic; many very fine, fine, medium, and

coarse roots; many very fine irregular pores; 55 percent

pebbles; slightly acid; clear smooth boundary.

AC-10 to 27 inches; very dark brown (10YR 2/2) extremely

gravelly loamy sand, dark brown (10YR 3/3) dry; single

grain; loose; many very fine and fine and common

medium and coarse roots; common fine irregular pores;

about 70 percent pebbles; about 10 percent marine

shells; strongly effervescent; neutral; clear smooth

boundary.

C1-27 to 45 inches; extremely gravelly coarse sand that is

mostly dark gray (10YR 4/1) and gray (10YR 5/1) but is

variegated black to white; single grain; loose; few fine

and medium roots; many medium irregular pores;

about 65 percent pebbles; about 25 percent marine

shells; violently effervescent; mildly alkaline; clear

smooth boundary.

C2-45 to 60 inches; extremely gravelly sand that is

mostly dark gray (10YR 4/1) and gray (10YR 5/1) but is

variegated black and white; single grain; loose; few

very fine and fine roots; many medium irregular

pores; about 60 percent pebbles and 5 percent

cobbles; about 25 percent marine shells; violently

effervescent; mildly alkaline.

The content of rock fragments in the particle-size

control section ranges from 55 to 70 percent. The content

of marine shell fragments ranges from 5 to 25 percent.

The shell fragments are all less than 0.5 inch in size.

The A horizon has value of 2 or 3 when moist and 3 or

4 when dry and chroma of 1 or 2 when moist and 2 or 3

when dry. The AC horizon has value of 2 or 3 when moist

and 3 or 4 when dry and chroma of 1 or 2 when moist

and 1 to 3 when dry. It is very gravelly loamy sand, very

gravelly sand, or extremely gravelly loamy sand. The C

horizon is variegated with hues of

10YR or 2.5Y. It is extremely gravelly sand or extremely

gravelly coarse sand.
Oakes Series

The Oakes series consists of very deep, well drained

soils formed in volcanic ash, colluvium, and slope alluvium

derived from glacial drift. These soils are on colluvial

mountain back slopes. Slopes are 5 to 80 percent. The

mean annual precipitation is 65 to 85 inches, and the mean

annual air temperature is about 44 degrees F.

These soils are loamy-skeletal, mixed, frigid Typic

Haplorthods.

Typical pedon of Oakes very gravelly loam, 30 to 60

percent slopes, 1.5 miles northwest of Glacier, 500 feet

north and 2,700 feet west of the southeast corner of sec.

36, T. 40 N., R. 6 E.

Oi-2 inches to 0; undecomposed needles, twigs, and

leaves.

A-0 to 5 inches; dark brown (7.5YR 4/4) very gravelly

loam, light brown (7.5YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable, slightly

sticky and nonplastic; weakly smeary; many very fine

and fine and common medium roots; many fine

irregular pores; about 40 percent pebbles and 15

percent cobbles; NaF pH 11.0; moderately acid; clear

smooth boundary.

Bs1-5 to 17 inches; dark brown (7.5YR 4/4) very

gravelly loam, pink (7.5YR 7/4) dry; weak fine

subangular blocky structure; soft, very friable,

slightly sticky and nonplastic; weakly smeary;

common very fine, many fine, and few medium

roots; many fine irregular pores; about 50 percent

pebbles and 10 percent cobbles; NaF pH 11.0;

moderately acid; clear wavy boundary.

Bs2-17 to 29 inches; dark brown (7.5YR 4/4) extremely

gravelly sandy loam, reddish yellow (7.5YR 6/6) dry;

weak medium subangular blocky structure; soft, very

friable, slightly sticky and nonplastic; weakly smeary;

many fine and medium and common coarse roots;

many fine irregular pores; about 45 percent pebbles,

15 percent cobbles, and 5 percent stones; NaF pH

11.0; moderately acid; gradual wavy boundary.

C-29 to 60 inches; olive brown (2.5Y 4/4) extremely

cobbly fine sandy loam, pale yellow (2.5Y 7/4) dry;

massive; slightly hard, friable, nonsticky and

nonplastic; common fine, many medium, and common

coarse roots; many fine irregular pores; about 40

percent pebbles, 25 percent cobbles, and 10 percent

stones; NaF pH 10.5; moderately acid.

Volcanic ash influences the fine-earth fraction in the

upper 24 to 60 inches. The depth to bedrock is more than

60 inches. The content of rock fragments in the

control section ranges from 35 to 70 percent. It includes 25

to 60 percent pebbles, 5 to 25 percent cobbles, and 0 to 10

percent stones. Less than 15 percent of the rock fragments

are phyllite.

The A horizon has hue of 5YR to 10YR, value of 3 or 4

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and 2 to 6 when dry.

The Bs horizon has hue of 7.5YR to 10YR, value of 4 or 5

when moist and 5 to 7 when dry, and chroma of 2 to 6

when moist and dry. It is very gravelly loam or very gravelly

sandy loam.

The C horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 6 to 8 when dry, and chroma of 2 to 4

when moist and 3 or 4 when dry. It is extremely gravelly

loam, extremely gravelly fine sandy loam, extremely

gravelly sandy loam, or extremely cobbly fine sandy loam.

Oridia Series

The Oridia series consists of very deep, poorly drained

soils formed in alluvium. These soils are on flood plains.

Slopes are 0 to 2 percent. The average annual

precipitation is 35 to 55 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are coarse-silty, mixed, nonacid, mesic

Aeric Fluvaquents.

Typical pedon of Oridia silt loam, drained, 0 to 2

percent slopes, 2.5 miles southwest of Lynden, 20 feet

north and 2,620 feet east of the southwest corner of sec.

25, T. 40 N., R. 2 E.

Ap-0 to 10 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 very fine roots; many very

fine irregular pores; slightly acid; clear smooth

boundary.

Cg1-10 to 17 inches; dark grayish brown (2.5Y 4/2) silt

loam, light gray (2.5Y 7/2) dry; few fine prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; slightly hard, friable, nonsticky

and nonplastic; common very fine roots; many very fine

irregular pores; slightly acid; clear smooth boundary.

Cg2-17 to 32 inches; dark grayish brown (2.5Y 4/2) very

fine sandy loam, light brownish gray (2.5Y 6/2) dry;

common fine prominent yellowish brown (10YR 5/6)

mottles, brownish yellow (10YR 6/6) dry; massive;

slightly hard, friable, nonsticky and nonplastic; many

very fine irregular and few fine tubular pores; three

strata of very fine sand 0.5 inch thick within the horizon;

slightly acid; clear smooth boundary.
Cg3-32 to 60 inches; gray (5Y 5/1) and grayish brown

(2.5Y 5/2) very fine sandy loam, light gray (5Y 7/1

and 2.5Y 7/2) dry; many medium prominent yellowish

brown (10YR 5/6) mottles, brownish yellow (10YR

6/6) dry; massive; slightly hard, friable, nonsticky and

nonplastic; many very fine irregular and common fine

tubular pores; slightly acid.

The particle-size control section contains, by weighted

average, 8 to 18 percent clay and 0 to 15 percent fine

sand or coarser textured material. These soils have an

irregular distribution of organic matter with increasing

depth.

The Ap horizon has hue of 10YR or 2.5Y and value of

3 or 4 when moist and 6 or 7 when dry. The Cg

horizon has hue of 2.5Y or 5Y, value of 4 or 5 when

moist and 6 or 7 when dry, and chroma of 1 or 2 when

moist and dry.

Oso Series

The Oso series consists of moderately deep, well

drained soils formed in volcanic ash, loess, glacial till,

and colluvium derived from metasedimentary rocks (fig.

7). These soils are on ridges, plateaus, and high

mountain back sloes. Slopes are 5 to 60 percent. The

average annual precipitation is 70 to 90 inches, and the

mean annual air temperature is about 42 degrees F.

These soils are coarse-loamy, mixed Typic

Cryorthods.

Typical pedon of Oso silt loam, in an area of KindyOso complex, 5 to 40 percent slopes; 2.5 miles

Oi-4 to 3 inches; undecomposed needles, twigs,

cones, and dead moss.

Oa-3 inches to 0; decomposed organic mat; many

 very fine, fine, medium, and coarse roots.

E-0 to 1 inch; dark reddish gray (5YR 4/2) silt loam,

pinkish gray (5YR 6/2) dry; massive; slightly hard,

friable, nonsticky and slightly plastic; weakly smeary;

many very fine and fine and common medium and

coarse roots; common very fine irregular pores;

about 5 percent rounded pebbles and 5 percent

angular pebbles; NaF pH 10.0; strongly acid; abrupt

smooth boundary.

Bs1-1 to 3 inches; dark reddish brown (5YR 3/3) silt

loam, yellowish red (5TY 4/6 dry; moderate fine

subangular blocky structure; slightly hard, firm,

nonsticky and slightly plastic; weakly smeary;

common very fine and fine and few medium roots;

common very fine irregular pores; about 5 percent

rounded pebbles and 5 percent angular pebbles; NaF

pH 10.5; very strongly acid; clear smooth boundary.

Bs2-3 to 14 inches; dark brown (7.5YR 4/4) gravelly

Figure 7.-Profile of Oso silt loam, in an area of the Kindy-Oso

complex, 5 to 40 percent slopes. Bedrock is at a depth of 23

itches. Depth is marked in feet.
silt loam, strong brown (7.5YR 5/6) dry; hard, firm,

nonsticky and slightly plastic; weakly smeary; many

very fine, fine, and medium and few coarse roots;

common very fine irregular pores; about 5 percent

rounded pebbles and 10 percent angular pebbles; NaF

pH 10.5; strongly acid; clear smooth boundary.

BC-14 to 38 inches; dark yellowish brown (10YR 4/4)

gravelly silt loam, light yellowish brown (10YR 6/4) dry;

moderate fine subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

few very fine, fine, and medium roots; common very

fine irregular pores; about 5 percent rounded pebbles

and 25 percent angular pebbles; NaF pH 10.5;

moderately acid; clear smooth boundary.

2R-38 inches; fractured metasedimentary rock.

The depth to lithic contact is 20 to 40 inches. The

content of rock fragments in the control section ranges

from 15 to 35 percent, although individual horizons contain

as much as 50 percent pebbles.

Some pedons have an A horizon. This horizon has

hue of 5YR or 7.5YR, value of 4 to 6 when moist and

dry, and chroma of 2 to 4 when moist and dry.

The Bs horizon has hue of 5YR or 7.5YR, value of 3 or

4 when moist and 4 or 5 when dry, and chroma of 3 to 6

when moist and dry. It is silt loam, gravelly silt loam, or

gravelly loam.

The BC horizon has hue of 7.5YR or 10YR, value of 5 to

7 when dry, and chroma of 4 to 6 when moist and dry. It is

gravelly silt loam or gravelly loam. Some pedons have a C

horizon.

Pangborn Series

The Pangborn series consists of very deep, very poorly

drained soils formed in herbaceous and woody organic

deposits. These soils are in depressions on outwash

terraces, till plains, and stream terraces. Slopes are 0 to

2 percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are dysic, mesic Typic Medisaprists.

Typical pedon of Pangborn muck, drained, 0 to 2

percent slopes, 5 miles northeast of Lynden, 500 feet

south and 2,500 feet west of the northeast corner of sec.

1, T. 40 N., R. 3 E.

Op-0 to 15 inches; dark reddish brown (5YR 3/2) muck,

dark brown (7.5YR 3/2) dry; moderate medium

granular structure; slightly hard, very friable, nonsticky

and nonplastic; about 80 percent fiber, 5 percent

rubbed; many very fine and fine roots; extremely acid;

clear smooth boundary.

Oa1-15 to 29 inches; dark reddish brown (5YR 2/2)

muck, dark brown (7.5YR 3/2) dry; moderate medium

subangular blocky structure; slightly hard, very friable,

nonsticky and nonplastic; about 60 percent fiber, 5

percent rubbed; many very fine and fine roots; very

strongly acid; clear smooth boundary.

Oa2-29 to 45 inches; dark reddish brown (5YR 2/2)

muck, dark brown (7.5YR 3/2) dry; moderate medium

subangular blocky structure; slightly hard, very friable,

nonsticky and nonplastic; about 50 percent fiber, 5

percent rubbed; many very fine and fine roots; very

strongly acid; clear smooth boundary.

Oa3-45 to 60 inches; very dark brown (7.5YR 2/2) muck,

very dark grayish brown (10YR 3/2) dry; moderate

medium subangular blocky structure; slightly hard,

very friable, nonsticky and nonplastic; about 30

percent fiber, 2 percent rubbed; common very fine

roots; very strongly acid.

Fibers are mostly from grasses and sedges, but pedons

contain 0 to 15 percent wood fragments. The fiber content

ranges from 30 to 80 percent when unrubbed and from 2

to 12 percent when rubbed. Thin, discontinuous layers of

volcanic ash and diatomaceous earth (0.5 inch to 2 inches

thick) are at a depth of 24 to 48 inches in some pedons.

The Oa horizon has hue of 5YR to 10YR, value of 2 to 4

when moist and 2 to 5 when dry, and chroma of 0 to 3

when moist and dry.

Pickett Series

The Pickett series consists of moderately deep, well

drained soils formed in colluvium derived from graywacke

and argillite with an admixture of volcanic ash. These soils

are on glacially modified back slopes and ridgetops.

Slopes are 5 to 60 percent. The mean annual precipitation

is 30 to 40 inches, and the mean annual air temperature

is about 49 degrees F.

These soils are loamy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Pickett very gravelly silt loam, in an

area of Pickett-Rock outcrop complex, 30 to 60 percent

slopes; on Lummi Island, 3,500 feet north and 1,000 feet

west of the southeast corner of sec. 23, T. 37 N., R. 1 E.

Oi-1.5 inches to 0; needles, leaves, and twigs.

A-0 to 2 inches; dark brown (7.5YR 3/3) gravelly silt

loam, brown (7.5YR 5/4) dry; weak coarse granular

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; many very fine and fine roots; many

medium irregular pores; about 25 percent angular

pebbles and 5 percent rounded
pebbles; NaF pH 10.0; slightly acid; clear smooth

boundary.

Bs1-2 to 15 inches; dark brown (7.5YR 4/4) very

gravelly silt loam, reddish yellow (7.5YR 7/6) dry;

weak coarse granular structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine, fine, and medium and common coarse roots;

many medium irregular pores; about 40 percent

angular pebbles and 5 percent rounded pebbles;

NaF pH 10.5; slightly acid; clear smooth boundary.

Bs2-15 to 29 inches; dark brown (7.5YR 4/4) very

gravelly silt loam, reddish yellow (7.5YR 7/6) dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; common

fine, many medium, and few coarse roots; many fine

irregular pores; about 55 percent angular pebbles; NaF

pH 11.0; moderately acid; abrupt smooth boundary.

2R-29 inches; fractured, hard graywacke.

The depth to bedrock and the thickness of the part of

the profile influenced by volcanic ash are 20 to 40 inches.

The content of rock fragments in the control section ranges

from 35 to 55 percent angular pebbles, from 0 to 5 percent

rounded pebbles, and from 0 to 10 percent angular

cobbles.

The A horizon has value of 3 or 4 when moist and 4 to

7 when dry and chroma of 2 to 4 when moist and 4 to 6

when dry. In areas where it has value and chroma of 3 or

less, it is less than 7 inches thick. The Bs horizon has

hue of 7.5YR or 10YR, value of 3 or 4 when moist and 5 to

7 when dry, and chroma of 4 to 6 when dry.

Plichuck Series

The Pilchuck series consists of very deep, somewhat

excessively drained soils formed in alluvium. These soils

are on flood plains. Slopes are 0 to 3 percent. The

average annual precipitation is 45 to 60 inches, and the

mean annual air temperature is about 49 degrees F.

These soils are mixed, mesic Dystric

Xeropsamments.

Typical pedon of Pilchuck loamy fine sand, 0 to 3

percent slopes, 1.5 miles northeast of Van Zandt, 1,000

feet north and 1,100 feet east of the southwest corner of

sec. 33, T. 39 N., R. 5 E.

Oi-2 inches to 0; undecomposed needles, leaves, and

twigs.

A-0 to 3 inches; black (10YR 2/1) fine sandy loam, very

dark grayish brown (10YR 3/2) dry; weak fine granular

structure; soft, very friable, nonsticky and

nonplastic; many very fine and common fine roots;

many fine irregular pores; moderately acid; clear wavy

boundary.

C1-3 to 13 inches; very dark grayish brown (10YR 3/2) fine

sand, dark grayish brown (10YR 4/2) dry; single grain;

loose; few very fine and common fine, medium, and

coarse roots; many fine irregular pores; moderately

acid; clear smooth boundary.

C2-13 to 25 inches; dark brown (10YR 3/3) loamy fine

sand, brown (10YR 4/3) dry; single grain; loose; many

fine, medium, and coarse roots; many fine irregular

pores; moderately acid; clear smooth boundary.

C3-25 to 44 inches; very dark brown (10YR 2/2) fine

sand, dark gray (10YR 4/1) dry; single grain; loose;

common fine, many medium, and few coarse roots;

many medium irregular pores; moderately acid; abrupt

smooth boundary.

C4-44 to 60 inches; black (10YR 2/1) sand, very dark gray

(10YR 3/1) dry; single grain; loose; many coarse

irregular pores; slightly acid.

The content of rock fragments in the particle-size

control section is 0 to 15 percent by weighted average.

The A horizon has hue of 10YR or 2.5Y, value of 2 or 3

when moist and 3 or 4 when dry, and chroma of 1 to 3

when moist and dry. Some pedons do not have an A

horizon.

The C horizon has hue of 10YR or 2.5Y, value of 2 to 4

when moist and 3 to 5 when dry, and chroma of 1 to 3

when moist and dry. It is sand, fine sand, or loamy fine

sand.

Potchub Series

The Potchub series consists of moderately deep,

moderately well drained soils formed in an admixture of

volcanic ash, loess, and colluvium over glacial till. These

soils are on high mountain back slopes and ridges. Slopes

are 8 to 60 percent. The average annual precipitation is 70

to 100 inches, and the mean annual air temperature is

about 42 degrees F.

These soils are coarse-loamy, mixed Humic

Cryorthods.

Typical pedon of Potchub loam, 30 to 60 percent

slopes, 2 miles south of Glacier, 600 feet north and

1,400 feet east of the southwest corner of sec. 17, T. 39

N., R. 7 E.

Oi-8 to 2 inches; undecomposed needles, leaves, and

twigs.

Oa-2 inches to 0; decomposed forest litter; many very

fine, fine, medium, and coarse roots.

E-0 to 2 inches; dark brown (7.5YR 4/2) silt loam,
pinkish gray (7.5YR 6/2) dry; massive; hard, firm,

slightly sticky and nonplastic; weakly smeary; common

very fine and coarse and many fine and medium roots;

common very fine irregular pores; about 10 percent

weathered pebbles and 5 percent hard cobbles; NaF

pH 10.0; strongly acid; abrupt smooth boundary.

Bhs-2 to 7 inches; strong brown (7.5YR 4/6) loam,

strong brown (7.5YR 5/6) dry; dark reddish brown

(5YR 3/3) organic stains, reddish brown (5YR 5/4) dry;

moderate fine subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

common very fine, many fine and medium, and few

coarse roots; common very fine irregular pores; about

10 percent weathered pebbles and 5 percent hard

cobbles; NaF pH 12.0; strongly acid; clear smooth

boundary.

Bs1-7 to 11 inches; strong brown (7.5YR 5/6) gravelly

loam, reddish yellow (7.5YR 6/6) dry; weak fine

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; common very

fine, fine, and medium roots; common very fine

irregular pores; about 10 percent hard pebbles, 15

percent weathered pebbles, and 5 percent hard

cobbles; NaF pH 12.0; strongly acid; clear wavy

boundary.

Bs2-11 to 29 inches; strong brown (7.5YR 5/6) gravelly

sandy loam, reddish yellow (7.5YR 7/6) dry; moderate

fine subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; few very fine

and fine roots; many fine irregular pores; about 15

percent hard pebbles, 20 percent soft pebbles, and 10

percent hard cobbles; NaF pH 11.5; strongly acid; clear

wavy boundary.

Bs3-29 to 39 inches; brown (7.5YR 5/4) gravelly sandy

loam, pink (7.5YR 7/4) dry; weak coarse subangular

blocky structure; hard, firm, nonsticky and nonplastic;

weakly smeary; few very fine, fine, and medium roots;

common fine irregular pores; about 10 percent hard

pebbles, 15 percent weathered pebbles, and 5 percent

hard cobbles; NaF pH 11.5; strongly acid; abrupt

smooth boundary.

2Cd-39 to 60 inches; light olive brown (2.5Y 5/4), dense

glacial till that breaks to gravelly sandy loam, pale

yellow (2.5Y 7/4) dry; massive; very hard, very firm,

nonsticky and nonplastic; weakly smeary; about 15

percent hard pebbles and 20 percent weathered

pebbles; moderately acid.

The depth to dense, compact glacial till is 20 to 40

inches. The part of the profile influenced by volcanic ash

ranges from 30 to 60 inches. The control section contains

0 to 15 percent weathered rock fragments and 15 to 35

percent hard rock fragments. The total content

of rock fragments ranges from 15 to 35 percent.

The E horizon has hue of 7.5YR or 10YR, value of 3 to 5

when moist and 5 to 7 when dry, and chroma of 1 or 2

when moist and dry.

The Bs horizon has hue of 5YR to 10YR, value of 3 to 5

when moist and 4 to 7 when dry, and chroma of 3 to 6

when moist and dry. It is gravelly loam or gravelly silt

loam.

The 2Cd horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. It is dense glacial till that breaks to

gravelly loam, gravelly sandy loam, very gravelly loam, or

very gravelly sandy loam.

Puget Series

The Puget series consists of very deep, poorly drained

soils formed in alluvium on flood plains. Slopes are 0 to 2

percent. The average annual precipitation is 35 to 55

inches, and the mean annual air temperature is about 50

degrees F.

These soils are fine-silty, mixed, nonacid, mesic

Aeric Fluvaquents.

Typical pedon of Puget silt loam, drained, 0 to 2 percent

slopes, 2 miles northeast of Everson, 2,000 feet north and

10 feet west of the southeast corner of sec. 19, T. 40 N., R.

4 E.

Ap-0 to 9 inches; dark grayish brown (10YR 4/2) silt loam,

light gray (10YR 7/2) dry; common fine prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; weak medium granular structure;

slightly hard, friable, slightly sticky and plastic; many

very fine and common fine roots; many very fine

irregular pores; moderately acid; abrupt smooth

boundary.

C1-9 to 16 inches; grayish brown (2.5Y 5/2) silt loam,

light gray (2.5Y 7.2) dry; many medium prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; hard, firm, slightly sticky and

slightly plastic; many very fine roots; many very fine

irregular and few fine tubular pores; moderately acid;

clear smooth boundary.

C2-16 to 34 inches; gray (5Y 5/1) silt loam, light gray (5Y

7/1) dry; many large prominent yellowish brown (10YR

5/6) mottles, brownish yellow (10YR 6/6) dry; massive;

hard, friable, slightly sticky and plastic; many very fine

roots; many very fine irregular and common fine tubular

pores; slightly acid; clear smooth boundary.

C3-34 to 60 inches; dark gray (5Y 4/1) silt loam, light

gray (5Y 7/1) dry; many large prominent yellowish

brown (10YR 5/6) mottles, brownish yellow (10YR 6/6)

dry; massive; hard, friable, slightly sticky and
plastic; common very fine roots; many very fine

irregular and common fine tubular pores; slightly

acid.

The control section contains, by weighted average, 18 to

35 percent clay and 0 to 15 percent sand coarser than

very fine sand. These soils have an irregular distribution of

organic matter with increasing depth.

The A horizon has hue of 10YR or 2.5Y and value of 3 or

4 when moist and 6 or 7 when dry. The C horizon has hue

of 10YR, 2.5Y, or 5Y, value of 4 or 5 when moist and 6 or 7

when dry, and chroma of 1 or 2 when moist and dry.

Puyallup Series

The Puyallup series consists of very deep, well drained

soils formed in alluvium. These soils are on flood plains

and low river terraces. Slopes are 0 to 2 percent. The

average annual precipitation is 35 to 60 inches, and the

mean annual air temperature is about 50 degrees F.

These soils are coarse-loamy over sandy or sandyskeletal, mixed, mesic Fluventic Haploxerolls.

Typical pedon of Puyallup fine sandy loam, 0 to 2

percent slopes, 0.25 mile southeast of Lynden, 1,800 feet

south and 900 feet east of the northwest corner of sec.

21, T. 40 N., R. 3 E.

Ap-0 to 6 inches; very dark grayish brown (10YR 3/2) fine

sandy loam, grayish brown (10YR 5/2) dry; weak fine

and medium granular structure; soft, very friable,

nonsticky and nonplastic; many very fine roots; many

very fine irregular pores; slightly acid; clear wavy

boundary.

A1-6 to 12 inches; very dark grayish brown (10YR 3/2)

loam, grayish brown (10YR 5/2) and light brownish gray

(10YR 6/2) dry; weak fine subangular blocky structure

parting to weak fine granular; soft, very friable, slightly

sticky and nonplastic; common very fine roots; many

very fine irregular pores; neutral; clear smooth

boundary.

A2-12 to 19 inches; very dark grayish brown (10YR 3/2)

fine sandy loam, light brownish gray (10YR 6/2) and light

gray (10YR 7/2) dry; weak medium subangular blocky

structure; soft, very friable, nonsticky and nonplastic;

common very fine roots; many very fine irregular pores;

neutral; abrupt smooth boundary.

C1-19 to 27 inches; very dark grayish brown (10YR 3/2)

sand, dark grayish brown (10YR 4/2) dry; single grain;

loose; few very fine roots; many fine irregular pores;

few pebbles; neutral; abrupt smooth boundary.

2C2-27 to 60 inches; very dark grayish brown (2.5Y 3/2)

sand, dark grayish brown (2.5Y 4/2) dry; single grain;

loose; many fine irregular pores; neutral.

The depth to the 2C horizon is 15 to 30 inches. The

Moloch epipedon is 10 to 15 inches thick. The upper part of

the particle-size control section has 5 to 15 percent clay,

and the lower part has 0 to 5 percent clay.

The A horizon has hue of 10YR to 2.5Y, value of 2 or 3

when moist and 3 to 5 when dry, and chroma of 2 or 3

when moist and 3 or 4 when dry. In places the lower part of

the A horizon has value of 6 or 7 when dry.

The 2C horizon has hue of 10YR or 2.5Y, value of 2 to 4

when moist and 4 or 5 when dry, and chroma of 1 to 4

when moist and dry. It is loamy sand, sand, or gravelly

sand.

Revel Series

The Revel series consists of moderately deep, well

drained soils formed in a mixture of volcanic ash,

colluvium, and slope alluvium derived dominantly from

sandstone, siltstone, and glacial till. These soils are on

mountain back slopes, ridges, and plateaus. Slopes are 5 to

60 percent. The average annual precipitation is 45 to 65

inches, and the mean annual air temperature is about 45

degrees F.

These soils are coarse-loamy, mixed, frigid Typic

Haplorthods.

Typical pedon of Revel loam, 30 to 60 percent slopes,

6.5 miles south of Bellingham, 600 feet north and 100 feet

west of the southeast corner of sec. 30, T. 37 N., R. 3 E.

Oi-1.5 inches to 0.5 inch; needles, leaves, and twigs.

Oa-0.5 inch to 0; decomposed needles, leaves, and

 twigs; many very fine and common fine roots.

A-0 to 4 inches; dark brown (7.5YR 4/4) loam, brown

(7.5YR 5/4) dry; weak fine subangular blocky

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; common very fine and few fine and

medium roots; many fine irregular pores; about 5

percent hard rounded pebbles and 15 percent

weathered angular pebbles; NaF pH 10.0; moderately

acid; clear smooth boundary.

Bs-4 to 16 inches; dark brown (7.5YR 4/4) loam,

yellowish brown (10YR 5/4) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; common fine and medium

roots; many fine irregular pores; about 35 percent

weathered angular pebbles; NaF pH 11.0;

moderately acid; clear smooth boundary.

C-16 to 35 inches; dark yellowish brown (10YR 4/4)

sandy loam, light yellowish brown (10YR 6/4) dry;
massive; soft, very friable, nonsticky and nonplastic;

weakly smeary; few fine and medium roots; many fine

irregular pores; about 60 percent weathered angular

pebbles and 10 percent soft angular cobbles; NaF pH

10.5; strongly acid; abrupt smooth boundary.

2Cr-35 inches; sandstone; few fine roots within rock

fractures.

The depth to sandstone or siltstone and the thickness

of the part of the profile influenced by volcanic ash are

20 to 40 inches. The content of rock fragments in the

control section ranges from 35 to 65 percent weathered

pebbles, from 0 to 15 percent weathered cobbles, and

from 0 to 15 percent hard, rounded pebbles.

The A horizon has hue of 7.5YR or 10YR, value of 2 to 4

when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist and dry. Some pedons have an E horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 3 or 4

when moist and dry. It is loam or sandy loam.

The C horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 6 to 8 when dry, and chroma of 3 or 4

when moist and dry. It is loam, sandy loam, or fine sandy

loam.

Rinker Series

The Rinker series consists of moderately deep, well

drained soils formed in a mixture of volcanic ash,

colluvium, and slope alluvium derived dominantly from

phyllite. These soils are on mountain back slopes and

shoulder slopes. Slopes are 8 to 60 percent. The average

annual precipitation is 60 to 80 inches, and the mean

annual air temperature is about 44 degrees F.

These soils, are loamy-skeletal, mixed, frigid Typic

Haplorthods.

Typical pedon of Rinker very channery silt loam, 30 to

60 percent slopes, 5 miles southeast of Acme, 1,500 feet

south and 2,200 feet west of the northeast corner of sec.

13, T. 37 N., R. 5 E.

Oi-4 to 3.5 inches; undecomposed needles, twigs, and

leaves.

Oa-3.5 inches to 0; decomposed forest litter; many

very fine, fine, medium, and coarse roots.

E-0 to 2 inches; brown (7.5YR 5/2) very channery silt

loam, pinkish gray (7.5YR 7/2) dry; massive; soft, very

friable, slightly sticky and slightly plastic; many very

fine and fine roots; many very fine irregular pores;

about 30 percent channers and 10 percent pebbles;

extremely acid; abrupt wavy boundary.

Bs1-2 to 7 inches; dark brown (7.5YR 4/4 and 3/4) very

channery silt loam, light brown (7.5YR 6/4) and strong

brown (7.5YR 5/6) dry; moderate medium subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; many fine and medium and

common coarse roots; many very fine irregular pores;

about 40 percent channers and 5 percent pebbles;

NaF pH 9.4; very strongly acid; clear wavy boundary.

Bs2-7 to 11 inches; dark yellowish brown (10YR 4/4)

extremely channery silt loam, very pale brown (10YR

7/4) dry; weak fine subangular blocky structure; soft,

very friable, nonsticky and nonplastic; weakly smeary;

many fine and medium and common coarse roots;

many very fine irregular pores; about 45 percent

channers, 10 percent pebbles, and 10 percent cobbles;

NaF pH 10.5; strongly acid; clear wavy boundary.

C-11 to 30 inches; olive brown (2.5Y 4/4) extremely

channery loam, pale yellow (2.5Y 7/4) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many

medium and coarse roots; many very fine irregular

pores; about 60 percent channers and 10 percent

cobbles; NaF pH 12.0; strongly acid; clear wavy

boundary.

2R-30 inches; fractured phyllite.

The depth to phyllite and the thickness of the part of the

profile influenced by volcanic ash are 20 to 40 inches. The

content of rock fragments in the particle-size control

section ranges from 50 to 70 percent.

The E horizon has hue of 7.5YR or 10YR, value of 4 or 5

when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist and dry. Some pedons do not have an E

horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3

to 5 when moist and 5 to 7 when dry, and chroma of 3 or

4 when moist and dry. It is very channery loam or very

channery silt loam.

The C horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 4 to 6

when moist and dry. It is extremely channery loam,

extremely channery silt loam, or very channery loam.

Saar Series

The Saar series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash and colluvium over glacial till. These soils are

on mountain back slopes and shoulder slopes. Slopes are

5 to 60 percent. The average annual precipitation is 85 to

105 inches, and the mean annual air temperature is about

41 degrees F.
These soils are loamy-skeletal, mixed Humic

Cryorthods.

Typical pedon of Saar gravelly silt loam, 5 to 30 percent

slopes, 6 miles northwest of Glacier, 1,500 feet south and

1,200 feet west of the northeast corner of sec. 11, T. 40

N., R. 6 E.

Oi-7 to 6 inches; undecomposed needles, leaves, and

twigs.

Oa-6 inches to 0; decomposed needles, leaves, and

twigs; many very fine, fine, medium, and coarse roots.

E-0 to 4 inches; dark brown (7.5YR 4/2) gravelly silt

loam, pinkish gray (7.5YR 6/2) dry; weak fine

subangular blocky structure; slightly hard, friable,

slightly sticky and slightly plastic; many very fine and

fine and common medium and coarse roots; many

very fine irregular pores; about 15 percent pebbles;

NaF pH 10.0; very strongly acid; abrupt smooth

boundary.

Bhs1-4 to 14 inches; dark brown (7.5YR 4/4) very

gravelly silt loam, strong brown (7.5YR 5/6) dry; dark

reddish brown (5YR 2/2) organic stains, dark reddish

brown (5YR 3/2) dry; weak fine subangular blocky

structure; slightly hard, friable, nonsticky and

nonplastic; weakly smeary; many very fine and fine and

common medium and coarse roots; many very fine

irregular pores; about 40 percent pebbles; NaF pH

10.0; very strongly acid; clear smooth boundary.

Bhs2-14 to 22 inches; dark brown (10YR 3/3) very gravelly

loam, yellowish brown (10YR 5/4) dry; dark reddish

brown (5YR 2/2) organic stains, dark reddish brown

(5YR 3/2) dry; weak fine subangular blocky structure;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; few very fine and common fine and medium

roots; many very fine irregular pores; about 35 percent

pebbles; NaF pH 11.5; strongly acid; clear smooth

boundary.

BC-22 to 29 inches; dark brown (10YR 3/3) very gravelly

loam, pale brown (10YR 6/3) dry; massive; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

few fine and medium roots; many very fine irregular

pores; about 50 percent pebbles; NaF pH 11.0;

strongly acid; abrupt smooth boundary.

2Cd-29 to 60 inches; gray (5Y 5/1), dense glacial till that

breaks to extremely gravelly loam, gray (5Y 6/1) dry;

massive; very hard, firm, nonsticky and nonplastic;

about 70 percent pebbles; NaF pH 10.5; strongly acid.

The depth to dense glacial till is 20 to 40 inches. The

thickness of the solum and of the part of the profile

influenced by volcanic ash is 20 to 40 inches. The

content of rock fragments in the particle-size control

section ranges from 35 to 60 percent.

The E horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs horizon has hue of 5YR or 7.5YR, value of 3

to 5 when moist and 4 to 6 when dry, and chroma of 4 to

6 when moist and dry. It is very gravelly loam or very

gravelly silt loam.

The BC horizon and the C horizon, if it occurs, have

hue of 10YR or 2.5Y, value of 3 to 5 when moist and 6 or 7

when dry, and chroma of 2 to 4 when moist and dry. They

are very gravelly loam or very gravelly silt loam.

The 2Cd 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 to 4

when moist and dry. It is dense glacial till that breaks to

very gravelly loam, extremely gravelly loam, or extremely

gravelly sandy loam.

Sandun Series

The Sandun series consists of very deep, well drained

soils formed in a mixture of loess and volcanic ash over

glacial outwash derived from dunite. These soils are on

outwash terraces, terrace escarpments, and mountain

foot slopes. Slopes are 5 to 60 percent. The average

annual precipitation is 70 to 90 inches, and the mean

annual air temperature is about 43 degrees F.

These soils are sandy-skeletal, serpentinitic, frigid

Typic Haplorthods.

Typical pedon of Sandun very gravelly sandy loam, 30

to 60 percent slopes, 6.5 miles east of Van Zandt, 1,900

feet north and 1,900 feet east of the southwest corner of

sec. 20, T. 38 N., R. 6 E.

Oi-3 inches to 0; undecomposed leaves, needles,

twigs, and wood fragments.

A-0 to 3 inches; dark reddish brown (5YR 3/4) gravelly

sandy loam, brown (7.5YR 5/4) dry; moderate fine and

medium granular structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; common very fine and

fine and few medium roots; common very fine irregular

pores; about 30 percent pebbles; NaF pH 11.5;

strongly acid; clear wavy boundary.

Bs1-3 to 11 inches; dark brown (7.5YR 3/4) very

gravelly sandy loam, strong brown (7.5YR 5/6) dry;

weak medium subangular blocky structure parting to

weak medium granular; soft, very friable, nonsticky and

nonplastic; weakly smeary; few very fine and common

fine and medium roots; common very fine irregular

pores; about 50 percent pebbles; NaF pH 12.0;

moderately acid; abrupt irregular boundary.
Bs2-11 to 24 inches; dark brown (7.5YR 4/4) very

gravelly sandy loam, strong brown (7.5YR 5/6) dry;

weak coarse subangular blocky structure; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common very fine and fine and few medium roots;

common very fine irregular pores; about 50 percent

pebbles; NaF pH 12.0; moderately acid; clear smooth

boundary.

2BC-24 to 32 inches; dark yellowish brown (10YR 4/4) very

gravelly loamy sand, brownish yellow (10YR 6/6) dry;

massive; loose, nonsticky and nonplastic; weakly

smeary; few very fine and fine roots; common very fine

irregular pores; about 55 percent pebbles; NaF pH

12.0; moderately acid; abrupt smooth boundary.

2C1-32 to 36 inches; dark yellowish brown (10YR 4/4)

very gravelly loamy sand; light yellowish brown (2.5Y

6/4) dry; massive; hard, firm, nonsticky and nonplastic;

weakly smeary; very few very fine roots; many fine

irregular pores; about 50 percent pebbles; NaF pH

12.0; moderately acid; abrupt smooth boundary.

2C2-36 to 60 inches; olive brown (2.5Y 4/4) very

gravelly loamy sand, light yellowish brown (2.5Y 6/4)

dry; single grain; loose; very few very fine roots;

many fine irregular pores; about 55 percent pebbles;

NaF pH 12.0; slightly acid.

The content of rock fragments in the control section

ranges from 40 to 80 percent. The rock fragments are

dominantly dunite. The thickness of the solum and of the

part of the profile influenced by volcanic ash ranges from

20 to 35 inches.

The A horizon has hue of 5YR to 10YR, value of 3 or 4

when moist and 4 or 5 when dry, and chroma of 3 or 4

when moist and dry.

The Bs horizon has hue of 5YR to 10YR, value of 3 to 5

when moist and 5 to 7 when dry, and chroma of 3 to 6

when moist and 4 to 6 when dry. It is very gravelly sandy

loam or very cobbly sandy loam.

The 2BC and 2C horizons have hue of 10YR or 2.5Y,

value of 3 to 5 when moist and 4 to 6 when dry, and

chroma of 3 to 6 when moist and dry. They are very

gravelly loamy sand or very gravelly sand.

Sehome Series

The Sehome series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash and loess over glacial till. These soils are in

glacially modified mountain foot slopes and in valleys.

Slopes are 2 to 60 percent. The average annual

precipitation is 40 to 60 inches, and the mean annual air

temperature is about 49 degrees F.

These soils are coarse-loamy, mixed, mesic Typic

Haplorthods.

Typical pedon of Sehome loam, 2 to 8 percent slopes,

5.5 miles west of Wickersham, 1,300 feet north and 900

feet west of the southeast corner of sec. 32, T. 37 N., R. 4

E.

Oi-0.5 inch to 0; needles, leaves, twigs, and moss.

A-0 to 2 inches; dark brown (7.5YR 3/2) silt loam, brown

(7.5YR 4/2) dry; weak fine subangular blocky structure;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; few very fine and fine roots; many fine

irregular pores; about 5 percent pebbles; NaF pH less

than 9.0; very strongly acid; abrupt smooth boundary.

Bs1-2 to 11 inches; dark brown (7.5YR 4/4) loam, light

brown (7.5YR 6/4) dry; moderate fine and medium

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; few very fine, fine, and

medium roots; common fine irregular pores; about 5

percent pebbles and 5 percent cobbles; NaF pH 12.0;

strongly acid; clear smooth boundary.

Bs2-11 to 21 inches; dark yellowish brown (10YR 4/4) gravelly

loam, light yellowish brown (10YR 6/4) dry; weak fine

subangular blocky structure; soft, very friable, nonsticky

and slightly plastic; weakly smeary; few very fine, fine,

and medium roots; common fine irregular pores; about

20 percent pebbles and 5 percent cobbles; NaF pH

11.5; strongly acid; gradual smooth boundary.

Bs3-21 to 26 inches; dark yellowish brown (10YR 4/4)

gravelly loam, very pale brown (10YR 7/4) dry; weak

fine subangular blocky structure; soft, very friable,

nonsticky and slightly plastic; weakly smeary; common

fine and few medium roots; few very fine irregular

pores; about 30 percent pebbles and 5 percent

cobbles; strongly acid; abrupt smooth boundary.

2Cd-26 to 60 inches; grayish brown (2.5Y 5/2), dense

glacial till that breaks to very gravelly loam, light gray

(2.5Y 7/2) dry; few medium prominent brown (7.5YR

5/4) mottles, light brown (7.5YR 6/4) dry; massive;

hard, firm, nonsticky and nonplastic; about 60 percent

pebbles; NaF pH 10.0; moderately acid.

The depth to dense glacial till and the thickness of the

solum and of the part of the profile influenced by volcanic

ash are 24 to 40 inches. The content of rock fragments in

the particle-size control section ranges from 15 to 35

percent. Individual horizons contain as much as 50

percent rock fragments in the lower part of the control

section.

The A horizon has hue of 5YR to 10YR, value of 2 or
3 when moist and 3 to 5 when dry, and chroma of 2 to 4

when moist and dry. Some pedons have an E horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 6 or 7 when dry, and chroma of 4 to 6

when moist and dry. It is loam, gravelly loam, or gravelly

silt loam.

Some pedons have a C horizon. The 2Cd horizon has

value of 5 to 7 when moist and chroma of 2 to 4 when

moist and 2 to 6 when dry. It is dense glacial till that

crushes to very gravelly silt loam, very gravelly loam, or

very gravelly sandy loam.

Shalcar Series

The Shalcar series consists of very deep, very poorly

drained soils formed in herbaceous and woody organic

deposits over alluvium and glaciofluvial deposits. These

soils are in depressions on outwash terraces, till plains,

and stream terraces. Slopes are 0 to 2 percent. The

average annual precipitation is 35 to 55 inches, and the

mean annual air temperature is about 50 degrees F.

These soils are loamy, mixed, euic, mesic Terric

Medisaprists.

Typical pedon of Shalcar muck, drained, 0 to 2 percent

slopes, 2 miles southeast of Everson, 1,300 feet north

and 1,000 feet west of the southeast corner of sec. 5, T.

39 N., R. 4 E.

Oap-0 to 6 inches; black (10YR 2/1) muck, black (N 2/0)

dry; moderate medium granular structure; slightly hard,

very friable, nonsticky and nonplastic; about 15 percent

fiber, 3 percent rubbed; many very fine roots; very

strongly acid; abrupt irregular boundary.

Oa1-6 to 26 inches; black (10YR 2/1) muck, dark brown

(7.5YR 3/2) dry; moderate medium granular structure;

slightly hard, very friable, nonsticky and nonplastic;

about 30 percent fiber, 5 percent rubbed; common very

fine roots; very strongly acid; clear wavy boundary.

Oa2-26 to 37 inches; black (10YR 2/1) muck, very dark

grayish brown (10YR 3/2) dry; moderate medium

granular structure; slightly hard, very friable, nonsticky

and nonplastic; about 20 percent fiber, 5 percent

rubbed; common very fine roots; an intermittent layer of

strong brown (7.5YR 4/6) fine sandy loam (volcanic

ash), reddish yellow (7.5YR 6/6) dry; very strongly acid;

abrupt smooth boundary.

2C1-37 to 52 inches; very dark grayish brown (10YR

3/2) loam, grayish brown (2.5Y 5/2) dry; massive;

slightly hard, friable, slightly sticky and slightly plastic;

common fine irregular pores; about 5

percent pebbles; slightly acid; abrupt smooth

boundary.

3C2-52 to 60 inches; dark gray (N 4/0) gravelly sand,

gray (N 6/0) dry; single grain; loose; many fine

irregular pores; about 15 percent pebbles; moderately

acid.

The organic material is 16 to 51 inches thick. Fibers are

mostly from grasses and sedges, but pedons contain as

much as 10 percent wood fragments. The fiber content

ranges from 5 to 40 percent when unrubbed, and from 2

to 15 percent when rubbed. The bottom tier is generally

highest in fiber content. Thin, discontinuous layers of

volcanic ash and diatomaceous earth (0.5 inch to 2 inches

thick) are at a depth of 24 to 48 inches in some pedons.

The Oa horizon has hue of 5YR to 10YR or of N, value

of 2 to 4 when moist and 2 to 5 when dry, and chroma

of 0 to 3 when moist and dry.

The 2C1 horizon has hue of 10YR, 2.5Y, 5Y, or N,

value of 3 to 5 when moist and 5 to 8 when dry, and

chroma of 0 or 2 when moist and dry. It is silt loam,

loam, or sandy loam.

Below a depth of 40 inches, the 3C horizon has hue of

5Y or N, value of 4 or 5 when moist and 5 to 7 when dry,

and chroma of 0 or 1 when moist and dry. It has 0 to 60

percent pebbles. It is sand to clay loam in the fine-earth

fraction. This horizon is below a depth of 60 inches in

some pedons.

Shuksan Series

The Shuksan series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash, loess, and colluvium over glacial till. These

soils are on mountain slopes and plateaus. Slopes are 5

to 80 percent. The average annual precipitation is 85 to

105 inches, and the mean annual air temperature is about

41 degrees F.

These soils are loamy-skeletal, mixed Humic

Cryorthods.

Typical pedon of Shuksan gravelly silt loam, 5 to 30

percent slopes, 5 miles north of Glacier, 1,550 feet north

and 100 feet east of the southwest corner of sec. 13, T.

40 N., R. 6 E.

Oi-9 to 7 inches; leaves, needles, twigs, and wood

fragments.

Oa-7 inches to 0; decomposed forest litter; many very

fine, fine, medium, and coarse roots.

E-0 to 2 inches; brown (7.5YR 5/2) fine sandy loam,

pinkish gray (7.5YR 7/2) dry; moderate medium

subangular blocky structure; hard, friable, nonsticky

and nonplastic; many very fine, fine, medium, and
coarse roots; many fine irregular and few very fine

tubular pores; about 10 percent pebbles; NaF pH 9.2;

extremely acid; abrupt smooth boundary.

Bhs1-2 to 4 inches; dark reddish brown (5YR 3/2) silt

loam, dark reddish gray (5YR 4/2) dry; black (5YR 2/1)

organic stains throughout 80 percent of the soil matrix,

dark reddish brown (5YR 3/2) dry; moderate medium

subangular blocky structure; slightly hard, friable,

nonsticky and nonplastic; weakly smeary; many fine

and medium and common very fine and coarse roots;

many fine irregular pores; about 5 percent pebbles;

NaF pH 9.5; extremely acid; abrupt smooth boundary.

Bhs2-4 to 15 inches; strong brown (7.5YR 4/6) gravelly

silt loam, strong brown (7.5YR 5/6) dry; dark reddish

brown (5YR 3/2) organic stains throughout 50 percent

of the soil matrix, dark reddish gray (5YR 4/2) dry;

moderate medium subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

few very fine and common fine and medium roots;

many very fine irregular and few fine tubular pores;

about 25 percent pebbles and 5 percent cobbles; NaF

pH 10.6; very strongly acid; abrupt smooth boundary.

Bs1-15 to 29 inches; dark brown (7.5YR 4/4) very

gravelly loam, light brown (7.5YR 6/4) dry; dark reddish

brown (5YR 3/2) organic stains throughout 40 percent

of the soil matrix, dark reddish gray (5YR 4/2) dry;

weak fine subangular blocky structure; slightly hard,

friable, nonsticky and nonplastic; weakly smeary; few

fine roots; many fine irregular pores; about 40 percent

pebbles and 5 percent cobbles; NaF pH 11.0; very

strongly acid; clear smooth boundary.

Bs2-29 to 35 inches; dark yellowish brown (10YR 4/4)

very gravelly loam, yellowish brown (10YR 5/4) dry; dark

reddish brown (5YR 3/2) organic stains on faces of

peds, dark reddish gray (5YR 4/2) dry; massive;

slightly hard, friable, nonsticky and nonplastic; weakly

smeary; few fine irregular pores; about 40 percent

pebbles; NaF pH 11.5; strongly acid; abrupt wavy

boundary.

2Cd-35 to 60 inches; light olive brown (2.5Y 5/4), dense,

compact glacial till that breaks to very gravelly sandy

loam, pale yellow (2.5Y 7/4) dry; massive; hard, firm,

nonsticky and nonplastic; about 40 percent pebbles;

NaF pH 10.0; strongly acid.

The depth to compact glacial till is 20 to 40 inches.

The content of rock fragments in the particle-size control

section ranges from 35 to 50 percent.

The E horizon has hue of 5YR or 7.5YR, value of 4 or

5 when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bhs1 horizon has value of 2 to 4 when moist and 3

or 4 when dry and chroma of 2 or 3 when moist. The

Bhs2 horizon has hue of 5YR or 7.5YR, value of 5

or 6 when dry, and chroma of 4 to 6 when moist and 6 to

8 when dry. It is gravelly loam or gravelly silt loam.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 4 to 6

when moist and dry.

The 2Cd horizon has hue of 10YR to 5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 1 to 4

when moist and dry. It is dense glacial till that breaks to

very gravelly loam or very gravelly sandy loam.

Skipopa Series

The Skipopa series consists of very deep, somewhat

poorly drained soils formed in volcanic ash and loess over

glaciolacustrine sediments. These soils are on terraces.

Slopes are 0 to 8 percent. The average annual precipitation

is 30 to 50 inches, and the mean annual air temperature is

about 50 degrees F.

These soils are fine, mixed, mesic Aqualfic

Haplorthods.

Typical pedon of Skipopa silt loam, 0 to 8 percent

slopes, 1.5 miles north of Everson, 2,100 feet south and

100 feet east of the northwest corner of sec. 19, T. 40 N.,

R. 4 E.

Ap-0 to 8 inches; dark brown (10YR 3/3) silt loam, pale

brown (10YR 6/3) dry; weak fine subangular blocky

structure; soft, very friable, nonsticky and nonplastic;

weakly smeary; many very fine and common fine

roots; many very fine irregular pores; NaF pH 10.5;

moderately acid; clear smooth boundary.

Bs1-8 to 12 inches; dark brown (7.5YR 4/4) silt loam,

light brown (7.5YR 6/4) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; common very fine roots;

many very fine irregular pores; NaF pH 10.5;

moderately acid; clear smooth boundary.

Bs2-12 to 16 inches; dark yellowish brown (10YR 4/4) silt

loam, light yellowish brown (10YR 6/4) and very pale

brown (10YR 7/4) dry; few fine prominent grayish brown

(2.5Y 5/2) mottles, light gray (2.5Y 7/2) dry; moderate

fine subangular blocky structure; slightly hard, friable,

nonsticky and slightly plastic; weakly smeary; common

very fine roots; many very fine irregular pores; NaF pH

10.0; moderately acid; clear smooth boundary.

BC-16 to 20 inches; brown (10YR 5/3) and grayish

brown (2.5Y 5/2) silty clay loam, very pale brown

(10YR 7/3) and light gray (2.5Y 7/2) dry; many fine
prominent olive brown (2.5Y 4/4) mottles, light olive

brown (2.5Y 5/4) dry; moderate medium subangular

blocky structure; slightly hard, firm, slightly sticky and

slightly plastic; few very fine roots; common very fine

irregular pores; moderately acid; clear smooth

boundary.

2C1-20 to 29 inches; dark brown (10YR 4/3) and brown

(10YR 5/3) silty clay loam, brown (10YR 5/3) and very

pale brown (10YR 7/3) dry; common fine prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; hard, firm, sticky and plastic;

few very fine irregular pores; moderately acid; clear

smooth boundary.

2C2-29 to 44 inches; brown (10YR 5/3) silty clay loam,

pale brown (10YR 6/3) and very pale brown (10YR 7/3)

dry; common fine prominent yellowish brown (10YR 5/6)

mottles, brownish yellow (10YR 6/6) dry; massive; hard,

firm, sticky and plastic; moderately acid; clear smooth

boundary.

2C3-44 to 60 inches; light brownish gray (2.5Y 6/2) and

light yellowish brown (2.5Y 6/4) silty clay loam, light

gray (2.5Y 7/2) and pale yellow (2.5Y 7/4) dry; few fine

prominent dark reddish brown (5YR 2/2) mottles, dark

reddish brown (5YR 3/2) dry; massive; extremely hard,

extremely firm, sticky and plastic; neutral.

The thickness of the solum ranges from 14 to 24 inches.

By weighted average, the content of rock fragments in the

particle-size control section ranges from 0 to 10 percent.

The content of clay ranges from 15 to 30 percent in the

upper part of the control section and from 35 to 50 percent

in the lower part.

The A horizon has hue of 7.5YR or 10YR, value of 2 or 3

when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist and dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 5 to 7 when dry, and chroma of 3 or 4

when moist and dry. It is silt loam or silty clay loam.

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 or 3

when moist and dry. It is silty clay loam, silty clay, or clay.

Skykomish Series

The Skykomish series consists of very deep, somewhat

excessively drained soils formed in glacial outwash and

volcanic ash. These soils are on outwash terraces. Slopes

are 3 to 30 percent. The average annual precipitation is

60 to 80 inches, and the mean annual air temperature is

about 45 degrees F.

These soils are sandy-skeletal, mixed, frigid Typic

Haplorthods.

Typical pedon of Skykomish very gravelly loam, 3 to 30

percent slopes, 1 mile south of Glacier, 1,100 feet south

and 2,100 feet west of the northeast corner of sec. 12, T.

39 N., R. 6 E.

Oi-10 to 9 inches; undecomposed needles, leaves,

wood, and twigs.

Oa-9 inches to 0; decomposed wood, needles, leaves,

and twigs; many very fine, fine, medium, and coarse

roots.

E-0 to 2 inches; brown (7.5YR 5/2) fine sandy loam,

pinkish gray (7.5YR 7/2) dry; massive; soft, friable,

slightly sticky and slightly plastic; weakly smeary;

many fine and medium roots; many fine irregular

pores; about 10 percent pebbles; extremely acid;

clear wavy boundary.

Bs-2 to 14 inches; dark yellowish brown (10YR 4/4) very

gravelly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; soft, very

friable, slightly sticky and nonplastic; weakly smeary;

many very fine, fine, medium, and coarse roots; many

fine irregular pores; about 45 percent pebbles and 10

percent cobbles; strongly acid; clear wavy boundary.

2C1-14 to 30 inches; dark yellowish brown (10YR 4/4)

extremely gravelly loamy sand, light yellowish brown

(10YR 6/4) dry; single grain; loose; common fine and

medium roots; many medium irregular pores; about 55

percent pebbles and 20 percent cobbles; strongly acid;

gradual wavy boundary.

2C2-30 to 60 inches; brown (10YR 5/3) extremely

gravelly sand, very pale brown (10YR 7/3) dry;

single grain; loose; few fine roots; many medium

irregular pores; about 45 percent pebbles, 10

percent cobbles, and 10 percent stones; strongly

acid.

The thickness of the solum and of the part of the profile

influenced by volcanic ash and the depth to the 2C

horizon range from 14 to 20 inches. The content of rock

fragments in the control section ranges from 35 to 55

percent in the solum and from 60 to 75 percent in the

substratum.

The E horizon has value of 4 or 5 when moist and 6 or

7 when dry and chroma of 1 or 2 when dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 4 or

5 when moist and 5 or 6 when dry, and chroma of 3 or 4

when moist and dry. It is very gravelly loam or very

gravelly sandy loam. Some pedons have a BC horizon.

The 2C horizon has value of 4 or 5 when moist and 6
or 7 when dry and chroma of 3 or 4 when moist and

dry. It is extremely gravelly loamy sand or extremely

gravelly sand.

Snohomish Series

The Snohomish series consists of very deep, poorly

drained soils formed in alluvium underlain by herbaceous

and woody organic material. These soils are on flood plains.

Slopes are 0 to 2 percent. The average annual precipitation

is 35 to 50 inches, and the mean annual air temperature is

about 50 degrees F.

These soils are fine-silty, mixed, nonacid, mesic

Thapto-Histic Fluvaquents.

Typical pedon of Snohomish silt loam, drained, 0 to 2

percent slopes, 2 miles west of Everson, 600 feet south and

600 feet west of the northeast corner of sec. 34, T. 40 N.,

R. 3 E.

Ap-0 to 6 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,

firm, slightly sticky and slightly plastic; many very fine

roots; many very fine irregular pores; moderately acid;

clear smooth boundary.

C-6 to 17 inches; dark grayish brown (2.5Y 4/2) silt

loam, light gray (2.5Y 7/2) dry; few fine prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; slightly hard, firm, slightly

sticky and slightly plastic; many very fine roots; many

very fine irregular pores; moderately acid; abrupt

smooth boundary.

2Oa-17 to 40 inches; dark reddish brown (5YR 2/2)

sapric material, dark reddish brown (5YR 3/2) dry;

moderate medium subangular blocky structure; slightly

hard, very friable, nonsticky and nonplastic; about 80

percent fiber, 10 percent rubbed; strongly acid; abrupt

smooth boundary.

3C'-40 to 41 inches; strong brown (7.5YR 4/6) fine

sandy loam (volcanic ash), yellow (10YR 7/6) dry;

massive; slightly hard, friable, nonsticky and

nonplastic; weakly smeary; NaF pH 11.5; moderately

acid; abrupt smooth boundary.

4Oa'-41 to 60 inches; dark reddish brown (5YR 2/2)

sapric material, dark brown (7.5YR 3/2) dry; moderate

medium subangular blocky structure; slightly hard,

very friable, nonsticky and nonplastic; about 60

percent fiber, 10 percent rubbed; extremely acid.

The particle-size control section contains, by weighted

average, 18 to 35 percent clay and 0 to 15 percent fine

sand or coarser textured material in the mineral soil. These

soils have an irregular distribution of

organic matter with increasing depth. Depth to the organic

layer is 14 to 36 inches. Fibers are mostly from grasses

and sedges, but pedons contain as much as 15 percent

wood fragments. The fiber content ranges from 30 to 80

percent when unrubbed and from 2 to 12 percent when

rubbed. Thin, discontinuous layers of volcanic ash and

diatomaceous earth (0.5 inch to 2 inches thick) are at a

depth of 24 to 48 inches in some pedons.

The Ap horizon has hue of 10YR or 2.5Y and value of

3 or 4 when moist and 6 or 7 when dry.

The C horizon has hue of 2.5Y or 5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry.

The 2Oa horizon has hue of 5YR to 10YR or of N,

value of 2 to 4 when moist and 2 to 5 when dry, and

chroma of 0 to 3 when moist and dry.

The 3C horizon has hue of 7.5YR or 10YR, value of 4 or

5 when moist and 6 or 7 when dry, and chroma of 4 to 6

when moist and dry. It is fine sandy loam or loamy fine

sand. It is absent or intermittent in some pedons.

Snoqualmie Series

The Snoqualmie series consists of very deep, somewhat

excessively drained soils formed in alluvium. These soils

are on flood plains and low river terraces. Slopes are 0 to 3

percent. The average annual precipitation is 50 to 70

inches, and the mean annual air temperature is about 48

degrees F.

These soils are sandy-skeletal, mixed, mesic Dystric

Xerorthents.

Typical pedon of Snoqualmie gravelly loamy sand, 0 to

3 percent slopes, 1.5 miles east of Maple Falls, 800 feet

east and 2,100 feet north of the southwest corner of sec.

28, T. 40 N., R. 6 E.

Oi-1 inch to 0; undecomposed leaves and twigs; many

very fine and fine roots.

A-0 to 4 inches; very dark grayish brown (2.5Y 3/2) fine

sandy loam, grayish brown (2.5Y 5/2) dry; weak fine

subangular blocky structure; soft, very friable,

nonsticky and nonplastic; common very fine and fine

roots; many very fine irregular pores; about 10 percent

pebbles; slightly acid; clear smooth boundary.

C1-4 to 14 inches; very dark gray (10YR 3/1) very

gravelly coarse sand, gray (10YR 5/1) dry; single grain;

loose; few fine and medium roots; many fine irregular

pores; about 50 percent pebbles; neutral; clear wavy

boundary.

C2-14 to 60 inches; very dark gray (10YR 3/1) and

dark gray (10YR 4/1) very gravelly sand; single
grain; loose; many fine irregular pores; about 40

percent pebbles; neutral.

The depth to the C horizon is 4 to 14 inches. The

content of rock fragments in the particle-size control

section ranges from 35 to 60 percent.

The A horizon has hue of 10YR or 2.5Y, value of 2 or 3

when moist and 4 or 5 when dry, and chroma of 1 or 2

when moist and dry.

The C horizon has hue of 10YR or 2.5Y, value of 2 to 4

when moist and 4 or 5 when dry, and chroma of 1 or 2

when moist and dry. It is very gravelly sand, extremely

gravelly sand, or extremely gravelly loamy sand.

Sorensen Series

The Sorensen series consists of very deep, well drained

soils formed in a mixture of volcanic ash, loess, and

colluvium derived from glacial till. The till was derived from

phyllite. These soils are on mountain back slopes and toe

slopes. Slopes are 8 to 60 percent. The average annual

precipitation is 65 to 80 inches, and the mean annual air

temperature is about 44 degrees F.

These soils are loamy-skeletal, mixed, frigid Typic

Haplorthods.

Typical pedon of Sorensen very gravelly silt loam, 30 to

60 percent slopes, 4 miles southeast of Van Zandt, 2,000

feet south and 600 feet east of the northwest corner of

sec. 26, T. 38 N., R. 5 E.

Oi-4 to 2 inches; undecomposed needles, leaves, and

twigs.

Oa-2 inches to 0; decomposed needles, leaves, and

twigs.

A-0 to 2 inches; dark brown (7.5YR 3/2) gravelly silt

loam, yellowish brown (10YR 5/4) dry; moderate fine

granular structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; many very fine and fine

roots; many very fine irregular pores; about 30 percent

pebbles; NaF pH 10.0; strongly acid; abrupt smooth

boundary.

Bs1-2 to 7 inches; dark brown (7.5YR 4/4) very gravelly

silt loam, light yellowish brown (10YR 6/4) dry;

moderate coarse subangular blocky structure; soft,

very friable, slightly sticky and slightly plastic; weakly

smeary; many very fine and common fine roots; many

very fine irregular pores; about 30 percent pebbles

and 10 percent cobbles; NaF pH 10.5; strongly acid;

abrupt smooth boundary.

Bs2-7 to 13 inches; yellowish brown (10YR 5/4) very

gravelly loam, pale yellow (2.5Y 7/4) dry; weak fine

subangular blocky structure; soft, very friable,

slightly sticky and slightly plastic; weakly smeary;

common very fine and fine roots; many very fine

irregular pores; about 25 percent pebbles and 10

percent cobbles; NaF pH 12.0; strongly acid; clear

wavy boundary.

BC-13 to 26 inches; light brownish gray (2.5Y 6/2) very

gravelly loam, light gray (2.5Y 7/2) dry; moderate fine

subangular blocky structure; soft, very friable, slightly

sticky and slightly plastic; weakly smeary; common very

fine and few fine and medium roots; many very fine

irregular pores; about 30 percent pebbles and 10

percent cobbles; NaF pH 11.5; strongly acid; clear

smooth boundary.

C-26 to 60 inches; light olive gray (5Y 6/2) very gravelly

silt loam, light gray (5Y 7/1) dry; massive; soft, very

friable, slightly sticky and slightly plastic; weakly

smeary; few very fine and fine roots; many very fine

irregular pores; about 35 percent pebbles; NaF pH

11.5; strongly acid.

The thickness of the solum is 18 to 30 inches. The

thickness of the part of the profile influenced by volcanic

ash is 30 to more than 60 inches. The content of rock

fragments in the particle-size control section ranges from

35 to 60 percent pebbles and channers and from 0 to 15

percent cobbles. More than 15 percent of the rock

fragments are phyllitic.

The A horizon has hue of 5YR to 10YR, value of 3 to 5

when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist and dry. Some pedons have an E horizon

instead of an A horizon.

The Bs horizon has hue of 7.5YR to 2.5Y, value of 4 or

5 when moist and 5 to 7 when dry, and chroma of 4 to 6

when moist and dry. It is very gravelly loam or very

gravelly silt loam.

The BC and C horizons have hue of 2.5Y or 5Y,

value of 4 to 6 when moist and 6 to 8 when dry, and

chroma of 1 to 4 when moist and dry. They are very

gravelly loam, very gravelly silt loam, or very gravelly

sandy loam.

Springsteen Series

The Springsteen series consists of moderately deep, well

drained soils formed in a mixture of volcanic ash,

colluvium, and glacial till derived from phyllite. These soils

are on high mountain back slopes. Slopes are 30 to 60

percent. The average annual precipitation is 75 to 90

inches, and the mean annual air temperature is about 43

degrees F.

These soils are loamy-skeletal, mixed Typic

Cryorthods.

Typical pedon of Springsteen very gravelly loam, 30
to 60 percent slopes, 6.5 miles east of Acme, 2,300 feet

south and 1,600 feet east of the northwest corner of sec.

17, T. 37 N., R. 6 E.

Oa-5 to 4 inches; undecomposed needles, leaves, and

twigs.

Oi-4 inches to 0; decomposed needles, leaves, and

twigs; many very fine, fine, and medium and

common coarse roots.

E-0 to 5 inches; brown (7.5YR 5/2) very gravelly loam,

pinkish gray (7.5YR 7/2) dry; massive; slightly hard,

friable, slightly sticky and slightly plastic; many very fine

and fine roots; many very fine irregular pores; about 35

percent pebbles; extremely acid; abrupt smooth

boundary.

Bs-5 to 13 inches; dark yellowish brown (10YR 4/4) very

gravelly loam, light yellowish brown (10YR 6/4) dry;

moderate medium subangular blocky structure; soft,

very friable, nonsticky and nonplastic; weakly smeary;

many very fine and fine roots; many very fine irregular

pores; about 40 percent pebbles and 10 percent

cobbles; NaF pH 11.0; very strongly acid; clear smooth

boundary.

C-13 to 24 inches; dark brown (10YR 4/3) very gravelly

loam, pale brown (10YR 6/3) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; many fine and medium

roots; many very fine irregular pores; about 30 percent

pebbles and 10 percent cobbles; NaF pH 9.6; very

strongly acid; clear smooth boundary.

2R-24 inches; phyllite; few fine roots in rock fractures.

The depth to fractured phyllite is 20 to 40 inches. The

control section contains 35 to 60 percent hard rock

fragments and 0 to 25 percent soft rock fragments.

The E horizon has hue of 7.5YR or 10YR, value of 4 to 6

when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 4 or

5 when moist and 5 or 6 when dry, and chroma of 3 or 4

when moist and dry. It is very gravelly loam or very

gravelly silt loam.

The C horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 6 to 8 when dry, and chroma of 2 to 4

when moist and dry. It is very gravelly loam or very cobbly

loam.

Squalicum Series

The Squalicum series consists of deep, moderately

well drained soils formed in a mixture of volcanic ash,

loess, and slope alluvium over glacial till. These soils are

on foothills and in valleys. Slopes are 5 to 60

percent. The average annual precipitation is 40 to 55

inches, and the mean annual air temperature is about 48

degrees F.

These soils are coarse-loamy, mixed, mesic Typic

Haplorthods.

Typical pedon of Squalicum gravelly loam, 5 to 15

percent slopes, 7 miles south of Bellingham, 600 feet

north and 2,250 feet east of the southwest corner of sec.

28, T. 37 N., R. 3 E.

Oi-1 inch to 0; undecomposed needles, leaves, and

twigs.

A-0 to 3 inches; very dark grayish brown (10YR 3/2) loam,

brown (10YR 5/3) dry; weak coarse granular structure;

soft, very friable, slightly sticky and nonplastic; weakly

smeary; many very fine and few fine roots; about 10

percent hard pebbles and 10 percent weathered

pebbles; NaF pH 10.5; moderately acid; abrupt smooth

boundary.

Bs1-3 to 17 inches; dark yellowish brown (10YR 4/6)

gravelly loam, yellow (10YR 7/6) dry; weak fine

subangular blocky structure; soft, very friable, slightly

sticky and nonplastic; weakly smeary; common very

fine, fine, and coarse roots; about 20 percent hard

pebbles and 5 percent weathered pebbles; NaF pH

11.5; moderately acid; clear wavy boundary.

Bs2-17 to 30 inches; dark yellowish brown (10YR 3/6)

gravelly loam, yellow (10YR 7/6) dry; massive; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common fine, medium, and coarse roots; about 25

percent hard pebbles and 10 percent weathered

pebbles; NaF pH 12.0; moderately acid; clear wavy

boundary.

C-30 to 44 inches; light olive brown (2.5Y 5/4) gravelly

loam, pale yellow (2.5Y 7/4) dry; massive; soft, very

friable, nonsticky and nonplastic; weakly smeary;

common fine and few medium and coarse roots; about

30 percent hard pebbles and 15 percent weathered

pebbles; NaF pH 12.0; moderately acid; abrupt smooth

boundary.

2Cd-44 to 60 inches; olive gray (5Y 5/2), dense glacial

till that breaks to gravelly loam, light gray (5Y 7/2) dry;

massive; very hard, firm, nonsticky and nonplastic;

about 30 percent hard pebbles and 5 percent

weathered pebbles; NaF pH 10.0; moderately acid.

The depth to dense, compact glacial till and the

thickness of the part of the profile influenced by volcanic

ash range from 40 to 60 inches. The thickness of the

solum is 17 to 35 inches. The content of rock fragments in

the particle-size control section ranges from 20 to 35

percent, although individual horizons
contain as much as 50 percent hard coarse fragments.

The control section also includes 0 to 15 percent

weathered coarse fragments by weighted average.

The A horizon has hue of 7.5YR or 10YR and chroma of 2

 to 4 when moist and 3 or 4 when dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 to 5

when moist and 5 to 7 when dry, and chroma of 3 to 6

when moist and dry. It is loam, gravelly loam, or gravelly

fine sandy loam.

The C horizon has hue of 10YR or 2.5Y, value of 3 to 5

when moist and 6 or 7 when dry, and chroma of 3 or 4

when moist and dry. It is gravelly loam, gravelly fine sandy

loam, gravelly sandy loam, or very gravelly sandy loam.

The 2Cd horizon has hue of 2.5Y or 5Y, value of 5 to 7

when moist and 6 to 8 when dry, and chroma of 2 to 4

when moist and dry. It is dense glacial till that breaks to

gravelly loam, gravelly sandy loam, very gravelly loam, or

very gravelly sandy loam.

Squires Series

The Squires series consists of moderately deep, well

drained soils formed in a mixture of volcanic ash, loess,

glacial till, and colluvium derived dominantly from phyllite.

These soils are on low mountain back slopes, toe slopes,

and foothills. Slopes are 5 to 60 percent. The average

annual precipitation is 45 to 60 inches, and the mean

annual air temperature is about 48 degrees F.

These soils are loamy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Squires very channery silt loam, 5 to

30 percent slopes, 4.5 miles east of Acme, 100 feet

south and 2,500 feet west of the northeast corner of sec.

12, T. 37 N., R. 5 E.

Oi-6 inches to 0; undecomposed needles, leaves, and

twigs; many very fine, fine, medium, and coarse roots.

E-0 to 2 inches; brown (7.5YR 5/2) channery silt loam,

pinkish gray (7.5YR 7/2) dry; weak medium subangular

blocky structure; slightly hard, friable, nonsticky and

nonplastic; many very fine, fine, and medium roots;

many very fine irregular pores; about 25 percent

pebbles and 5 percent cobbles; extremely acid; abrupt

wavy boundary.

Bs1-2 to 5 inches; dark brown (7.5YR 3/4) very channery

silt loam, strong brown (7.5YR 5/6) dry; dark brown

(7.5YR 3/2) organic stains, dark brown (7.5YR 4/4) dry;

weak medium subangular blocky structure; slightly

hard, friable, nonsticky and nonplastic; weakly smeary;

many very fine, fine, and

medium roots; many very fine irregular pores; about 25

percent channers and 10 percent cobbles; NaF pH

12.0; moderately acid; clear wavy boundary.

Bs2-5 to 12 inches; dark brown (7.5YR 4/4) very

channery loam, strong brown (7.5YR 5/6) dry; weak

medium subangular blocky structure; slightly hard,

friable, nonsticky and nonplastic; weakly smeary; many

very fine and common fine and medium roots; many

very fine irregular pores; about 35 percent channers

and 15 percent cobbles; NaF pH 12.0; moderately acid;

clear wavy boundary.

BC-12 to 18 inches; dark yellowish brown (10YR 4/4) very

channery loam, light yellowish brown (10YR 6/4) dry;

massive; soft, friable, nonsticky and nonplastic; weakly

smeary; common very fine, fine, and medium roots;

many very fine irregular pores; about 30 percent

channers and 15 percent cobbles; NaF pH 12.0;

moderately acid; clear wavy boundary.

C-18 to 30 inches; light olive brown (2.5Y 5/4) very

channery sandy loam, pale yellow (2.5Y 7/4) dry;

massive; soft, very friable, nonsticky and nonplastic;

weakly smeary; few fine and medium roots; many very

fine irregular pores; about 40 percent channers and 20

percent cobbles; NaF pH 12.0; moderately acid; abrupt

wavy boundary.

2R-30 inches; fractured phyllite.

The depth to phyllite and the thickness of the part of the

profile influenced by volcanic ash are 20 to 40 inches. The

content of rock fragments in the control section ranges

from 35 to 60 percent.

The E horizon has hue of 7.5YR or 10YR, value of 3 to 5

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. Some pedons have an A horizon

instead of an E horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3

or 4 when moist and 5 or 6 when dry, and chroma of 3 to

6 when moist and dry. It is very channery loam, very

gravelly loam, or very gravelly silt loam.

The C horizon has hue of 10YR or 2.5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry. It is very channery loam, very gravelly

loam, very channery silt loam, very gravelly silt loam, very

channery sandy loam, or very gravelly sandy loam.

Sumas Series

The Sumas series consists of very deep, poorly drained

soils formed in recent alluvium. These soils are on flood

plains. Slopes are 0 to 2 percent. The average annual

precipitation is 35 to 60 inches, and the mean
annual air temperature is about 50 degrees F.

These soils are fine-silty over sandy or sandy-skeletal,

mixed, nonacid, mesic Aeric Fluvaquents.

Typical pedon of Sumas silt loam, drained, 0 to 2

percent slopes, 2 miles southwest of Sumas, 2,000 feet

south and 100 feet west of the northeast corner of sec. 9,

T. 40 N., R. 4 E.

Ap-0 to 8 inches; dark grayish brown (10YR 4/2) silt loam,

light gray (10YR 7/2) dry; moderate fine and medium

subangular blocky structure; hard, friable, sticky and

plastic; common very fine and few fine roots; many

fine irregular and common fine tubular pores;

moderately acid; clear smooth boundary.

Cg1-8 to 26 inches; grayish brown (2.5Y 5/2) silt loam,

light gray (10YR 7/1) dry; common medium prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; hard, firm, sticky and plastic;

common very fine roots; many fine irregular pores and

many fine and common medium tubular pores; slightly

acid; abrupt wavy boundary.

2Cg2-26 to 60 inches; very dark grayish brown (2.5Y

3/2) sand, grayish brown (2.5Y 5/2) dry; few medium

prominent dark brown (7.5YR 3/4) mottles, strong

brown (7.5YR 5/6) dry; massive; slightly hard, very

friable, nonsticky and nonplastic; few very fine roots;

many medium irregular pores; slightly acid.

The depth to sand or gravelly sand, ranges from 14 to 36

inches. The upper part of the particle-size control section

has 18 to 35 percent clay and 0 to 15 percent fine sand or

coarser textured material. The content of rock fragments in

the lower part of the control section ranges from 0 to 10

percent.

The A horizon has hue of 10YR, 2.5Y, or 5Y, value of 2

to 4 when moist and 4 to 7 when dry, and chroma of 1 to

3 when moist and dry. It is mottled in some pedons.

The Cg1 horizon has hue of 10YR, 2.5Y, or 5Y, value

of 2 to 6 when moist and 4 to 8 when dry, and chroma of

1 or 2 when moist and dry. It is silt loam or

silty clay loam.

The 2Cg2 horizon has hue of 10YR, 2.5Y, or 5Y, value

of 3 to 5 when moist and 4 to 8 when dry, and chroma

of 1 or 2 when moist and dry. It is loamy fine sand,

loamy sand, sand, or gravelly sand.

Tacoma Series

The Tacoma series consists of very deep, very poorly

drained soils formed in recent alluvium. These soils are on

flood plains, deltas, and tidal flats. Slopes are 0 to 1

percent. The average annual precipitation is 30 to 40

inches, and the mean annual air temperature is about 50

degrees F.

These soils are coarse-silty, mixed, acid, mesic Sulfic

Fluvaquents.

Typical pedon of Tacoma silt loam, drained, 0 to 1

percent slopes, 3.5 miles southwest of Ferndale, 200 feet

south and 100 feet east of the northwest corner of sec. 7,

T. 38 N., R. 2 E.

Ap-0 to 7 inches; dark grayish brown (10YR 4/2) silt

loam, light gray (10YR 7/2) dry; common fine

prominent yellowish brown (10YR 5/6) mottles, brownish

yellow (10YR 6/6) dry; massive; very hard, firm,

slightly sticky and plastic; common very fine and fine

roots; many very fine irregular pores; very strongly

acid; clear wavy boundary.

C1-7 to 12 inches; dark grayish brown (2.5Y 4/2) silt

loam, gray (5Y 6/1) dry; many medium prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/6) dry; massive; very hard, friable, slightly

sticky and plastic; common very fine and fine roots;

common very fine irregular pores; very strongly acid;

clear smooth boundary.

C2-12 to 17 inches; dark gray (5Y 4/1) silt loam, light

gray (5Y 7/1) dry; many medium prominent strong

brown (7.5YR 5/6) mottles, yellowish brown (10YR

5/6) dry; massive; very hard, friable, sticky and

plastic; few very fine roots; common very fine irregular

pores; very strongly acid when moist, extremely acid

when dry; clear smooth boundary.

C3-17 to 26 inches; dark gray (5Y 4/1) silt loam, light

gray (5Y 7/1) dry; many medium prominent strong

brown (7.5YR 5/6) and dark yellowish brown (10YR 4/6)

mottles, strong brown (7.5YR 5/6) and olive brown

(2.5Y 6/6) dry; massive; very hard, friable, slightly

sticky and slightly plastic; few very fine roots; common

very fine irregular pores; very strongly acid when

moist, extremely acid when dry; clear smooth

boundary.

C4-26 to 37 inches; dark gray (5Y 4/1) silt loam, light

gray (5Y 7/1) dry; common medium prominent olive

brown (2.5Y 4/4) mottles, light olive brown (2.5Y 5/6)

dry; massive; hard, friable, slightly sticky and slightly

plastic; common very fine irregular pores; very strongly

acid when moist, extremely acid when dry; abrupt

smooth boundary.

C5-37 to 60 inches; dark gray (5Y 4/1) very fine sandy

loam, gray (5Y 6/1) dry; many coarse prominent

yellowish brown (10YR 5/6) mottles, brownish yellow

(10YR 6/8) dry; massive; hard, friable, slightly sticky

and slightly plastic; few very fine irregular pores; very

strongly acid.

The particle-size control section has, by weighted
average, 10 to 18 percent clay and 0 to 15 percent sand

coarser than very fine sand. Reaction is very strongly acid

or strongly acid when moist and extremely acid or very

strongly acid when dry.

The A horizon has hue of 10YR or 2.5Y and value of 6 or

7 when dry. Structure is granular or massive.

The C horizon has hue of 2.5Y, 5Y, or N, value of 6 or

7 when dry, and chroma of 0 to 2 when moist and dry. It is

dominantly silt loam or very fine sandy loam. In some

pedons, however, it has strata of sand or fine sandy loam

below a depth of 40 inches.

Tromp Series

The Tromp series consists of very deep, moderately well

drained soils that formed in a mixture of volcanic ash and

loess over glacial outwash. These soils are on outwash

terraces. Slopes are 0 to 2 percent. The average annual

precipitation is 40 to 55 inches, and the mean annual air

temperature is about 50 degrees F.

These soils are sandy, mixed, mesic Aquic

Haplorthods.

Typical pedon of Tromp loam, 0 to 2 percent slopes, 2

miles north of Ferndale, 2,300 feet south and 2,400 feet

east of the northwest corner of sec. 8, T. 39 N., R. 2 E.

Ap-0 to 11 inches; dark brown (10YR 3/3) loam, light

yellowish brown (10YR 6/4) dry; weak medium

subangular blocky structure parting to weak fine

granular; soft, very friable, nonsticky and nonplastic;

weakly smeary; many very fine and fine roots; many

very fine irregular pores; NaF pH 12.0; moderately acid;

abrupt smooth boundary.

Bs1-11 to 15 inches; dark brown (7.5YR 4/4) loam,

brownish yellow (10YR 6/6) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; common very fine and fine

roots; many very fine irregular pores; NaF pH 12.0;

strongly acid; clear smooth boundary.

Bs2-15 to 20 inches; strong brown (7.5YR 4/6) loam,

reddish yellow (7.5YR 6/6) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; common very fine and fine

roots; many very fine irregular pores; NaF pH 12.0;

strongly acid; abrupt smooth boundary.

BCs-20 to 26 inches; dark yellowish brown (10YR 4/4)

sandy loam, light yellowish brown (10YR 6/4) dry; many

fine prominent strong brown (7.5YR 5/8) mottles,

reddish yellow (7.5YR 6/8) dry; massive; slightly hard,

friable, nonsticky and nonplastic;

common very fine and fine roots; common fine

irregular pores; NaF pH 11.5; moderately acid;

abrupt smooth boundary.

2CBs-26 to 46 inches; olive brown (2.5Y 4/4), weakly

cemented sand, pale yellow (2.5Y 7/4) dry; common

medium prominent yellowish brown (10YR 5/6) and

dark grayish brown (2.5Y 4/2) mottles, brownish yellow

(10YR 6/6) and light gray (2.5Y 7/2) dry; massive;

slightly hard, friable, nonsticky and nonplastic; many

fine irregular pores; NaF pH 12.0; moderately acid;

clear irregular boundary.

2C-46 to 60 inches; dark grayish brown (2.5Y 4/2) and

grayish brown (2.5Y 5/2) sand, light brownish gray

(2.5Y 6/2) and light gray (2.5Y 7/2) dry; common

medium prominent yellowish brown (10YR 5/6) mottles,

brownish yellow (10YR 6/6) dry; single grain; loose;

NaF pH 11.0; moderately acid.

The thickness of the part of the profile influenced by

volcanic ash and the thickness of the solum are 14 to 30

inches. The content of rock fragments in the control

section ranges from 0 to 5 percent pebbles.

The A horizon has hue of 7.5YR or 10YR, value of 3 or 4

when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist and dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 4 to 6 when dry, and chroma of 3 to 6

when moist and dry. It is silt loam, loam, or sandy loam.

The BCs and 2CBs horizons have hue of 10YR or 2.5Y,

value of 3 to 5 when moist and 4 to 7 when dry, and

chroma of 2 to 4 when moist and dry. The 2CB horizon is

weakly cemented and has slightly hard or hard consistence

when dry. It is massive or contains 1 to 15 percent ortstein

fragments 0.25 inch to 2 inches in diameter.

The 2C horizon has hue of 10YR to 5Y, value of 3 to 5

when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist and dry. It is loamy sand or sand.

Twinsi Series

The Twinsi series consists of moderately deep,

moderately well drained soils formed in colluvium and

glacial till derived from dunite with an admixture of volcanic

ash and loess. These soils are on high mountain back

slopes and shoulder slopes. Slopes are 30 to 60 percent.

The average annual precipitation is 90 to 105 inches, and

the mean annual air temperature is about 41 degrees F.

These soils are loamy-skeletal, serpentinitic Typic

Cryorthods.

Typical pedon of Twinsi very gravelly loam, 30 to 60
percent slopes, 9 miles southeast of Van Zandt, 2,400 feet

north and 700 feet east of the southwest corner of sec. 3,

T. 37 N., R. 6 E.

Oi-8 to 2 inches; undecomposed needles, twigs, and

bark.

Oa-2 inches to 0; decomposed organic mat; many very

fine, fine, medium, and common coarse roots.

E-0 to 1 inch; brown (7.5YR 5/2) gravelly fine sandy

loam, pinkish gray (7.5YR 7/2) dry; weak medium

subangular blocky structure parting to weak fine

granular; soft, very friable, nonsticky and nonplastic;

many very fine, fine, and medium and common coarse

roots; many very fine irregular pores; about 30 percent

pebbles; NaF pH less than 9.0; very strongly acid;

abrupt smooth boundary.

Bs1-1 to 6 inches; strong brown (7.5YR 4/6) very

gravelly loam, reddish yellow (7.5YR 6/6) dry; dark

reddish brown (5YR 3/3) organic stains on faces of

peds, reddish brown (5YR 4/4) dry; weak medium

subangular blocky structure parting to weak medium

granular; soft, friable, nonsticky and nonplastic; weakly

smeary; many fine and medium and common very fine

and coarse roots; many very fine irregular pores;

about 30 percent pebbles and 10 percent cobbles;

NaF pH 11.0; strongly acid; clear wavy boundary.

Bs2-6 to 14 inches thick; strong brown (7.5YR 4/6) very

gravelly loam, reddish yellow (7.5YR 6/6) dry;

moderate medium subangular blocky structure; slightly

hard, firm, slightly sticky and nonplastic; weakly

smeary; few very fine and fine roots; common very fine

irregular pores; about 40 percent pebbles and 15

percent cobbles; NaF pH 10.0; strongly acid; clear

irregular boundary.

Bs3-14 to 22 inches; dark yellowish brown (10YR 4/4)

very gravelly loam, light yellowish brown (10YR 6/4)

dry; weak coarse subangular blocky structure; slightly

hard, friable, slightly sticky and slightly plastic; weakly

smeary; very few very fine and fine roots; common

very fine irregular pores; about 40 percent pebbles

and 15 percent cobbles; NaF pH 10.0; strongly acid;

abrupt smooth boundary.

2C-22 to 27 inches; grayish brown (2.5Y 5/2) very

gravelly sandy loam, light brownish gray (2.5Y 6/2)

dry; massive; slightly hard, firm, nonsticky and

nonplastic; few very fine irregular pores; about 40

percent pebbles and 10 percent cobbles; NaF pH 9.8;

slightly acid; abrupt smooth boundary.

2Cr-27 to 60 inches; dark yellowish brown (10YR 4/4),

dense, compact glacial till that breaks to very gravelly

loam, light yellowish brown (10YR 6/4) dry; massive;

hard, firm, nonsticky and nonplastic; few

very fine irregular pores; about 40 percent pebbles;

NaF pH 10.5; slightly acid.

The depth to dense glacial till ranges from 20 to 40

inches. The thickness of the solum is 13 to 30 inches.

The content of rock fragments in the control section

ranges from 45 to 75 percent. It includes 5 to 20 percent

cobbles.

The E horizon has hue of 5YR or 7.5YR, value of 4 or

5 when moist and 6 or 7 when dry, and chroma of 2 or 3

when moist and dry.

The Bs1 horizon has hue of 5YR or 7.5YR, value of 3

to 5 when moist and 4 to 7 when dry, and chroma of 3 to

6 when moist and dry. It is very gravelly loam or extremely

gravelly loam. The Bs2 and Bs3 horizons have hue of

7.5YR or 10YR, value of 4 or 5 when moist and 5 or 6

when dry, and chroma of 4 to 6 when moist and dry.

The C horizon has hue of 10YR or 2.5Y, value of 3 or 4

when moist and 5 to 7 when dry, and chroma of 2 to 6

when moist and dry. It is very gravelly loam, very gravelly

sandy loam, or extremely gravelly loam.

The 2Cr horizon has hue of 10YR or 2.5Y, value of 3 or

4 when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. It is dense glacial till that breaks to

very gravelly loam, very gravelly sandy loam, or extremely

gravelly loam.

Vanzandt Series

The Vanzandt series consists of moderately deep,

moderately well drained soils formed in volcanic ash,

loess, and slope alluvium over glacial till derived

dominantly from phyllite. These soils are on low mountain

toe slopes and in valleys. Slopes are 5 to 60 percent. The

mean annual precipitation is 50 to 70 inches, and the

mean annual temperature is about 47 degrees F.

These soils are loamy-skeletal, mixed, mesic Typic

Haplorthods.

Typical pedon of Vanzandt very gravelly loam, 5 to 15

percent slopes, 2 miles northeast of Acme, 400 feet south

and 2,200 feet east of the northwest corner of sec. 33, T.

38 N., R. 5 E.

Oi-1 inch to 0; undecomposed needles, leaves, and

twigs; many medium roots.

E-0 to 1.5 inches; dark brown (7.5YR 3/2) very gravelly

silt loam, brown (7.5YR 5/2) dry; weak fine granular

structure; soft, very friable, slightly sticky and slightly

plastic; weakly smeary; common medium and coarse

roots; many fine irregular pores; about 25 percent hard

pebbles and 20 percent channers; strongly acid; clear

smooth boundary.
Bs1-1.5 to 10 inches; dark brown (7.5YR 4/4) very

gravelly loam, light yellowish brown (10YR 6/4) dry;

weak fine subangular blocky structure; soft, very

friable, slightly sticky and slightly plastic; weakly

smeary; many very fine, fine, medium, and coarse

roots; many fine irregular pores; about 25 percent hard

pebbles and 10 percent channers; NaF pH 11.0;

moderately acid; abrupt smooth boundary.

Bs2-10 to 23 inches; dark yellowish brown (10YR 4/4)

very gravelly loam, very pale brown (10YR 7/4) dry;

weak fine and medium subangular blocky structure;

soft, friable, nonsticky and nonplastic; weakly smeary;

many fine, medium, and coarse roots; many fine

irregular pores; about 40 percent hard pebbles and 10

percent soft pebbles; NaF pH 11.0; moderately acid;

clear smooth boundary.

C-23 to 31 inches; light yellowish brown (2.5Y 6/4)

very gravelly loam, white (2.5Y 8/2) dry; few fine

prominent strong brown (7.5YR 5/6) mottles, reddish

yellow (7.5YR 6/6) dry; massive; slightly hard,

friable, nonsticky and nonplastic; many fine and

medium roots; common fine irregular pores; about

30 percent hard pebbles and 10 percent channers;

NaF pH 9.6; moderately acid; abrupt smooth

boundary.

2Cd-31 to 60 inches; light brownish gray (2.5Y 6/2),

dense glacial till that breaks to very gravelly loam,

white (2.5Y 8/2) dry; common fine prominent strong

brown (7.5YR 5/6) mottles, reddish yellow (7.5YR 6/6)

dry; massive; very hard, very firm, nonsticky and

nonplastic; few fine irregular pores; about 35 percent

hard pebbles and 10 percent channers; moderately

acid.

The depth to dense glacial till ranges from 24 to 40

inches. The thickness of the solum and of the part of the

profile influenced by volcanic ash is 17 to 28 inches. The

content of clay in the lower part of the control section is 10

to 15 percent. The content of rock fragments in the control

section ranges from 40 to 50 percent hard rock fragments

and from 0 to 10 percent weathered pebbles in the upper

part and from 40 to 60 percent rock fragments in the lower

part. The lower part includes pebbles, channers, and

cobbles.

The E horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist and dry. Some pedons have an A horizon

and do not have an E horizon.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 to 7 when dry, and chroma of 4 to 6

when moist and dry. It is very gravelly loam or very

gravelly silt loam.

Some pedons have a 2CB horizon.

The C horizon has hue of 2.5Y or 5Y, value of 5 to 8

when moist and 6 to 8 when dry, and chroma of 2 to 4

when moist and dry. It is very gravelly loam or very

gravelly sandy loam.

The 2Cd horizon has hue of 2.5Y or 5Y, value of 6 to 8

when moist and 5 to 8 when dry, and chroma of 2 to 4

when moist and dry. It is dense glacial till that breaks to

very gravelly loam or very gravelly sandy loam.

Welcome Series

The Welcome series consists of deep, well drained soils

formed in a mixture of volcanic ash, glacial till, colluvium,

and slope alluvium derived from sandstone. These soils are

on mountain ridges and shoulder slopes. Slopes are 5 to

60 percent. The average annual precipitation is 55 to 65

inches, and mean annual air temperature is about 44

degrees F.

These soils are coarse-loamy, mixed, frigid Typic

Haplorthods.

Typical pedon of Welcome loam, 5 to 30 percent slopes,

2 miles southeast of Van Zandt, 2,000 feet north and

1,900 feet west of the southeast corner of sec. 21, T. 38

N., R. 3 E.

Oi-3 to 2 inches; undecomposed needles, leaves, and

twigs.

Oa-2 inches to 0; decomposed forest litter.

E-0 to 2 inches; dark brown (10YR 4/3) silt loam, light

gray (10YR 7/2) dry; weak fine granular structure; soft,

very friable, nonsticky and nonplastic; weakly smeary;

many very fine and fine and common medium roots;

many very fine irregular pores; about 20 percent

weathered pebbles; NaF pH 9.4; strongly acid; abrupt

wavy boundary.

Bs1-2 to 6 inches; dark yellowish brown (10YR 3/4)

loam, light yellowish brown (10YR 6/4) dry; weak fine

granular structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; about 20 percent

weathered pebbles, 5 percent hard pebbles, and 5

percent hard cobbles; NaF pH 10.5; common very

fine, many fine and medium, and few coarse roots;

many very fine irregular pores; strongly acid; clear

wavy boundary.

Bs2-6 to 19 inches; dark yellowish brown (10YR 3/6)

loam, very pale brown (10YR 7/4) dry; weak fine

granular structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; about 30 percent

weathered pebbles, 10 percent hard pebbles, and 5

percent weathered cobbles; NaF pH 11.0; many very

fine and fine, common medium, and few coarse roots;

many very fine irregular pores; strongly acid; abrupt

wavy boundary.

C1-19 to 27 inches; light olive brown (2.5Y 5/6) sandy

loam, pale yellow (2.5Y 8/4) dry; massive; soft, very
friable, nonsticky and nonplastic; weakly smeary; about

30 percent weathered pebbles, 5 percent hard

pebbles, and 10 percent weathered cobbles; NaF pH

10.5; few very fine and common fine roots; many very

fine irregular pores; strongly acid; clear wavy boundary.

C2-27 to 50 inches; light olive brown (2.5Y 5/6) fine

sandy loam, pale yellow (2.5Y 7/4) dry; massive; soft,

very friable, nonsticky and nonplastic; weakly smeary;

about 20 percent weathered pebbles, 5 percent hard

pebbles, 5 percent weathered cobbles, and 5 percent

hard cobbles; NaF pH 10.5; few fine roots; common

very fine irregular pores; strongly acid; abrupt wavy

boundary.

2Cr-50 inches; sandstone; root mat of fine and

medium roots overlies bedrock.

The depth to sandstone is 40 to 60 inches. The content

of rock fragments in the control section ranges from 30 to

50 percent weathered pebbles, from 0 to 10 percent hard

pebbles, and from 5 to 15 percent weathered cobbles.

The E horizon has value of 3 or 4 when moist and 6 or

7 when dry and chroma of 2 or 3 when moist and dry.

The Bs horizon has value of 3 or 4 when moist and 5 to

7 when dry and chroma of 4 to 6 when moist and dry. It is

loam or silt loam.

The C horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 6 to 8 when dry, and chroma of 4 to 6

when moist and dry. It is sandy loam or fine sandy loam.

Whatcom Series

The Whatcom series consists of very deep, moderately

well drained soils formed in a mixture of loess and volcanic

ash over glaciomarine drift. These soils are in the higher

areas of glaciomarine drift plains. Slopes are 0 to 60

percent. The average annual precipitation is 35 to 55

inches, and the average annual air temperature is about 50

degrees F.

These soils are fine-loamy, mixed, mesic Aqualfic

Haplorthods.

Typical pedon of Whatcom silt loam, in an area of

Whatcom-Labounty silt loams, 0 to 8 percent slopes; 7

miles northeast of Bellingham, 20 feet north and 600 feet

east of the southwest corner of sec. 30, T. 39 N., R. 4 E.

Ap-0 to 9 inches; dark brown (10YR 3/3) silt loam, brown

(10YR 5/3) dry; weak fine granular structure; soft, very

friable, nonsticky and nonplastic; weakly smeary; many

very fine and common fine roots;

many very fine irregular pores; about 5 percent

pebbles and 2 percent concretions; NaF pH 10.5;

moderately acid; abrupt smooth boundary.

Bs1-9 to 13 inches; dark brown (7.5YR 4/4) silt loam,

light brown (7.5YR 6/4) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; many very fine roots; many

very fine irregular pores; about 5 percent pebbles and

1 percent concretions; NaF pH 11.5; moderately acid;

clear smooth boundary.

Bs2-13 to 16 inches; dark brown (7.5YR 3/4) silt loam,

light brown (7.5YR 6/4) dry; weak fine subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; many very fine roots; many

very fine irregular pores; about 5 percent pebbles and

1 percent concretions; NaF pH 12.0; moderately acid;

abrupt smooth boundary.

2Bt1-16 to 20 inches; light olive brown (2.5Y 5/4) loam,

pale yellow (2.5Y 7/4) dry; many medium prominent

dark yellowish brown (10YR 4/4) mottles, yellowish

brown (10YR 5/4) dry; moderate thick platy structure;

slightly hard, friable, slightly sticky and slightly plastic;

common very fine roots; many very fine irregular pores;

few thin patchy clay films on faces of peds; about 5

percent pebbles; NaF pH 9.8; moderately acid; clear

smooth boundary.

2Bt2-20 to 26 inches; light olive brown (2.5Y 5/4) loam,

light gray (2.5Y 7/2) dry; many coarse prominent

yellowish brown (10YR 5/6) mottles, reddish yellow

(7.5YR 6/6) dry; moderate thick platy structure; slightly

hard, friable, nonsticky and slightly plastic; few very

fine roots; many very fine irregular pores; few thin

patchy clay films on faces of peds; about 10 percent

pebbles; NaF pH 10.0; moderately acid; abrupt smooth

boundary.

2C1-26 to 35 inches; light olive gray (5Y 6/2) loam,

white (5Y 8/2) dry; many medium prominent mottles,

light olive brown (2.5Y 5/6) moist and dry; moderate

thick platy structure; very hard, firm, slightly sticky and

slightly plastic; common very fine irregular pores;

about 5 percent pebbles; NaF pH 9.4; neutral; clear

smooth boundary.

2C2-35 to 60 inches; dark gray (5Y 4/1) loam, light gray

(5Y 7/1) dry; moderate coarse blocky structure;

extremely hard, very firm, slightly sticky and slightly

plastic; very few very fine irregular pores; about 5

percent pebbles; NaF pH 9.6; mildly alkaline; slightly

effervescent.

The thickness of the part of the profile influenced by

volcanic ash and the depth to the 2C horizon are 14 to 28

inches. The content of rock in the particle-size control

section ranges from 0 to 10 percent in the upper part and

from 5 to 25 percent in the lower part. The
lower part of the control section ranges from 18 to 30

percent clay by weighted average.

The A horizon has hue of 7.5YR or 10YR, value of 3 or 4

when moist and 4 or 5 when dry, and chroma of 2 to 4

when moist and 3 or 4 when dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 5 or 6 when dry, and chroma of 4 to 6

when moist and dry. The 2Bt horizon has hue of 10YR or

2.5Y, value of 4 to 6 when moist and 5 to 7 when dry, and

chroma of 2 to 4 when moist and dry. It is dominantly loam,

gravelly loam, clay loam, gravelly clay loam, or silty clay

loam. In some pedons, however, it has thin strata of sandy

loam.

The 2C horizon has hue of 2.5Y or 5Y, value of 4 to 6

when moist and 6 to 8 when dry, and chroma of 1 or 2

when moist and dry. It is dominantly loam, gravelly loam,

clay loam, gravelly clay loam, or silty clay loam. It is blocky

or massive. In some pedons, however, it has thin strata of

sandy loam.

Whitehorn Series

The Whitehorn series consists of very deep, poorly

drained soils formed in volcanic ash, loess, glaciofluvial

deposits, and glaciomarine drift. These soils are on wavereworked glaciomarine drift plains. Slopes are 0 to 2

percent. The average annual precipitation is 30 to 40

inches, and the mean annual air temperature is about 50

degrees F.

These soils are fine-loamy, mixed, mesic Typic

Umbraqualfs.

Typical pedon of Whitehorn silt loam, 0 to 2 percent

slopes, 3 miles west of Ferndale, 1,000 feet south and

200 feet east of the northwest corner of sec. 35, T. 39

N., R. 1 E.

Ap-0 to 10 inches; very dark brown (10YR 2/2) silt loam,

dark grayish brown (10YR 4/2) dry; moderate fine

granular structure; hard, friable, slightly sticky and

slightly plastic; many very fine and fine roots; many

very fine irregular pores; NaF pH 9.4; moderately acid;

abrupt wavy boundary.

ABg-10 to 14 inches; dark brown (10YR 3/3) loam,

grayish brown (10YR 5/2) and light brownish gray

(10YR 6/2) dry; many fine distinct dark yellowish brown

(10YR 3/6 and 4/6) mottles, yellowish brown (10YR

5/6) dry; moderate medium subangular blocky

structure; hard, friable, slightly sticky and slightly

plastic; common very fine and fine roots; many very

fine irregular pores; NaF pH 9.4; moderately acid;

clear wavy boundary.

BAg-14 to 18 inches; dark grayish brown (10YR 4/2) and

light olive brown (2.5Y 5/4) very fine sandy loam,

light gray (10YR 7/2) and light yellowish

brown (10YR 6/4) dry; many coarse prominent dark

yellowish brown (10YR 3/4) and strong brown (7.5YR

4/6) mottles, brownish yellow (10YR 6/6) dry;

moderate medium subangular blocky structure; hard,

firm, slightly sticky and slightly plastic; common very

fine and fine roots; many very fine irregular pores;

about 5 percent pebbles; slightly acid; clear wavy

boundary.

Bg-1 8 to 26 inches; dark brown (10YR 4/3) and grayish

brown (10YR 5/2) very gravelly sandy loam, pale brown

(10YR 6/3) and light gray (10YR 7/2) dry; many coarse

prominent dark yellowish brown (10YR 4/6) mottles,

brownish yellow (10YR 6/6) and reddish yellow (7.5YR

6/6) dry; weak fine subangular blocky structure; hard,

friable, nonsticky and nonplastic; few very fine and fine

roots; many very fine irregular pores; about 35 percent

pebbles; slightly acid; abrupt wavy boundary.

Btg-26 to 33 inches; olive brown (2.5Y 4/4) and grayish

brown (2.5Y 5/2) loam, light yellowish brown (10YR 6/4)

and light gray (2.5Y 7/2) dry; many medium prominent

dark yellowish brown (10YR 4/6) mottles, brownish

yellow (10YR 6/6) dry; massive; very hard, firm, slightly

sticky and slightly plastic; about 5 percent pebbles;

neutral; clear wavy boundary.

2C-33 to 60 inches; olive brown (2.5Y 4/4) and brown

(10YR 5/3) silt loam, very pale brown (10YR 7/3) and

light gray (2.5Y 7/2) dry; common fine prominent dark

yellowish brown (10YR 4/6 and 3/4) mottles, brownish

yellow (10YR 6/6) dry; massive; very hard, very firm,

slightly sticky and slightly plastic; about 5 percent

pebbles; neutral.

The thickness of the solum is 20 to 40 inches. Depth to

the Bg horizon is 16 to 24 inches. By weighted average,

the particle-size control section has 10 to 18 percent clay

and 0 to 15 percent pebbles, although the Bg horizon

contains 0 to 40 percent pebbles.

The A and AB horizons have hue of 7.5YR or 10YR,

value of 2 or 3 when moist and 4 or 5 when dry, and

chroma of 2 or 3 when moist and dry. The A horizon is

mottled in some pedons.

The BAg horizon has hue of 10YR or 2.5Y, value of 4 to 6

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. It is loam, silt loam, or very fine sandy

loam. The Bg horizon has hue of 10YR or 2.5Y, value of 4

or 5 when moist and 6 or 7 when dry, and chroma of 2 to 4

when moist and dry. It is sandy loam, gravelly loam,

gravelly sandy loam, or very gravelly sandy loam. The Btg

and 2C horizons have hue of 10YR to 5Y, value of 4 to 6

when moist and 6 to 8 when dry, and chroma of 2 to 4

when moist and dry. They are loam, silt loam, clay loam,

or silty clay loam.
Wickersham Series

The Wickersham series consists of very deep, well

drained soils formed in alluvium derived dominantly from

phyllite. These soils are on alluvial fans and terraces.

Slopes are 0 to 8 percent. The average annual

precipitation is 55 to 65 inches, and the mean annual air

temperature is about 49 degrees F.

These soils are coarse-loamy over sandy or sandyskeletal, mixed, mesic Dystric Xerochrepts.

Typical pedon of Wickersham channery silt loam, 0 to 8

percent slopes, 0.5 mile west of Wickersham, 2,400 feet

north and 900 feet west of the southeast corner of sec. 31,

T. 37 N., R. 5 E.

A1-0 to 4 inches; very dark gray (5Y 3/1) channery silt

loam, gray (5Y 5/1) dry; weak fine subangular blocky

structure; slightly hard, friable, nonsticky and nonplastic;

many very fine, few fine, and many medium roots;

many very fine irregular pores; about 30 percent

channers; strongly acid; clear smooth boundary.

A2-4 to 12 inches; dark gray (5Y 4/1) channery silt loam,

gray (5Y 6/1) dry; weak fine subangular blocky

structure; slightly hard, friable, nonsticky and

nonplastic; many fine and medium and few coarse

roots; many very fine irregular pores; about 15 percent

channers; moderately acid; clear smooth boundary.

Bw-12 to 21 inches; grayish brown (2.5Y 5/2) silt loam,

light brownish gray (2.5Y 6/2) dry; weak fine

subangular blocky structure; slightly hard, firm,

nonsticky and nonplastic; common very fine and many

fine and medium roots; many very fine irregular pores;

about 5 percent channers; strongly acid; clear smooth

boundary.

2C1-21 to 38 inches; dark gray (5Y 4/1) extremely

channery loamy sand, gray (5Y 6/1) dry; single grain;

loose, friable, nonsticky and nonplastic; few very fine

and common fine roots; many very fine irregular

pores; about 50 percent channers and 20 percent

pebbles; moderately acid; clear smooth boundary.

2C2-38 to 44 inches; dark gray (5Y 4/1) channery sandy

loam, gray (5Y 6/1) dry; massive; soft, friable, nonsticky

and nonplastic; many very fine and fine roots; many

very fine irregular pores; about 15 percent channers

and 5 percent pebbles; moderately acid; clear smooth

boundary.

2C3-44 to 60 inches; dark gray (5Y 4/1) very channery

loamy sand, gray (5Y 6/1) dry; single grain; loose,

friable, nonsticky and nonplastic; few very fine roots;

many fine irregular pores; about 50 percent channers

and 10 percent pebbles; moderately acid.

The thickness of the solum and the depth to the 2C

horizon are 15 to 30 inches. The content of rock fragments

ranges from 5 to 25 percent in the upper part of the control

section and from 40 to 70 percent in the lower part. The

content of clay in the upper part of the particle-size control

section ranges from 6 to 18 percent.

The A horizon has hue of 2.5Y or 5Y, value of 3 or 4

when moist and 5 or 6 when dry, and chroma of 1 or 2

when moist and dry.

The Bw horizon has hue of 2.5Y or 5Y, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry. It is silt loam, loam, or channery silt

loam.

The 2C horizon has hue of 2.5Y or 5Y, value of 3 to 5

when moist and 5 or 6 when dry, and chroma of 1 or 2

when moist and dry. It is very channery loamy sand,

extremely channery loamy sand, channery sandy loam, or

sand.

Winston Series

The Winston series consists of very deep, well drained

soils formed in a mixture of loess and volcanic ash over

glacial outwash. These soils are on outwash terraces.

Slopes are 0 to 40 percent. The average annual

precipitation is 55 to 70 inches, and the mean annual air

temperature is about 48 degrees F.

These soils are coarse-loamy over sandy or sandyskeletal, mixed, mesic Typic Haplorthods.

Typical pedon of Winston silt loam, 0 to 3 percent

slopes, 4.5 miles north of Maple Falls, 400 feet south and

2,600 feet west of the northeast corner of sec. 1, T. 40 N.,

R. 5 E.

Oi-2 inches to 1 inch; undecomposed needles, twigs,

and dead moss.

Oa-1 inch to 0; decomposed forest litter; many fine and

common very fine, medium, and coarse roots.

A-0 to 2 inches; dark reddish brown (5YR 3/3) silt loam,

reddish brown (5YR 5/3) dry; weak fine granular

structure; soft, very friable, nonsticky and slightly

plastic; weakly smeary; many very fine, fine, medium,

and coarse roots; many fine irregular pores; about 5

percent fine pebbles; NaF pH 10.5; slightly acid; abrupt

smooth boundary.

Bs1-2 to 6 inches; dark brown (7.5YR 3/4) silt loam,

brown (7.5YR 5/4) dry; moderate fine subangular

blocky structure; slightly hard, firm, nonsticky and

slightly plastic; weakly smeary; common very fine, fine,

medium, and coarse roots; common fine irregular

pores; 5 percent concretions and 5 percent pebbles;

NaF pH 11.5; slightly acid; clear smooth boundary.
Bs2-6 to 11 inches; dark brown (7.5YR 3/4) loam, brown

(7.5YR 5/4) dry; weak fine subangular blocky structure;

slightly hard, firm, nonsticky and slightly plastic; weakly

smeary; common very fine and fine and few medium

and coarse roots; common very fine irregular pores;

about 5 percent fine pebbles; NaF pH 11.5; moderately

acid; clear smooth boundary.

Bs3-11 to 19 inches; dark yellowish brown (10YR 4/4) gravelly

loam, light yellowish brown (10YR 6/4) dry; weak fine

subangular structure; slightly hard, firm, nonsticky and

slightly plastic; weakly smeary; common very fine and

fine and few medium and coarse roots; common fine

irregular pores; about 10 percent fine angular pebbles

and 5 percent fine rounded pebbles; NaF pH 11.5;

moderately acid; gradual smooth boundary.

2CB-19 to 25 inches; dark yellowish brown (10YR 3/6) very

gravelly loamy sand, yellowish brown (10YR 5/4) dry;

massive; soft, friable, nonsticky and nonplastic; weakly

smeary; few very fine and fine roots; common fine

irregular pores; about 40 percent fine angular pebbles

and 15 percent rounded pebbles; NaF pH 11.0;

moderately acid; abrupt smooth boundary.

2C-25 to 60 inches; very dark grayish brown (10YR 3/2)

extremely gravelly sand, pale brown (10YR 6/3) dry;

single grain; loose; very few very fine roots; many fine

and medium irregular pores; about 35 percent angular

pebbles and 25 percent rounded pebbles; slightly acid.

The thickness of the solum and of the part of the profile

influenced by volcanic ash and the depth to the 2C

horizon range from 14 to 30 inches. The content of rock

fragments in the particle-size control section ranges from

5 to 35 percent in the upper part and from 40 to 70

percent in the lower part.

The A horizon has hue of 5YR or 7.5YR, value of 3 or

4 when moist and 4 to 6 when dry, and chroma of 2 to 4

when moist and dry.

The Bs horizon has hue of 5YR to 10YR, value of 3 or 4

when moist and 5 or 6 when dry, and chroma of 3 or 4

when moist and 4 to 6 when dry. It is silt loam, loam,

gravelly silt loam, or gravelly loam.

The 2CB horizon has value of 3 or 4 when moist and 5

or 6 when dry and chroma of 4 to 6 when moist and dry.

The 2C horizon has hue of 10YR to 5Y, value of 4 to 6

when moist and 5 or 6 when dry, and chroma of 2 to 4

when moist and dry. It is very gravelly or extremely

gravelly sand or loamy sand. It includes layers of stratified

coarse sand or sandy loam.

Wiseman Series

The Wiseman series consists of very deep, somewhat

excessively drained soils formed in alluvium derived from

phyllite. These soils are on alluvial fans. Slopes are 0 to 8

percent. The average annual precipitation is 55 to 65

inches, and the mean annual air temperature is about 48

degrees F.

These soils are sandy-skeletal, mixed, mesic Dystric

Xerorthents.

Typical pedon of Wiseman very channery sandy

loam, 0 to 8 percent slopes, 0.5 mile west of

Wickersham, 2,300 feet south and 2,200 feet east of the

northwest corner of sec. 31, T. 37 N., R. 5 E.

Oi-6 to 5 inches; undecomposed grass, moss, and

twigs.

Oa-5 inches to 0; decomposed grass, moss, and wood

ash; common very fine and fine roots.

A-0 to 4 inches; dark brown (7.5YR 3/4) channery loam,

brown (7.5YR 5/4) dry; weak fine subangular blocky

structure parting to weak fine granular; soft, very

friable, nonsticky and nonplastic; many very fine and

fine and few medium roots; many fine irregular pores;

about 30 percent channers; strongly acid; clear smooth

boundary.

C1-4 to 20 inches; dark yellowish brown (10YR 3/4) very

channery loamy sand, brownish yellow (10YR 6/6) dry;

weak fine granular structure; soft, very friable,

nonsticky and nonplastic; many very fine and fine and

few medium roots; many fine irregular pores; about 55

percent channers; moderately acid; clear smooth

boundary.

C2-20 to 26 inches; dark yellowish brown (10YR 3/4) very

channery sand, yellowish brown (10YR 5/4) dry; single

grain; loose; common very fine and fine and few

medium roots; many fine irregular pores; about 40

percent channers; strongly acid; clear smooth

boundary.

C3-26 to 35 inches; dark grayish brown (2.5Y 4/2) very

channery sand, pale yellow (2.5Y 7/4) dry; single

grain; loose; common very fine and fine and few

medium roots; many fine irregular pores; about 55

percent channers; moderately acid; clear smooth

boundary.

C4-35 to 60 inches; grayish brown (2.5Y 5/2) very

channery sand, light brownish gray (2.5Y 6/2) dry;

single grain; loose; few very fine, medium, and coarse

roots; many fine and medium irregular pores; about 50

percent channers; moderately acid.

The thickness of the solum is 2 to 8 inches. The content of

phyllite rock fragments in the particle-size
control section ranges from 45 to 80 percent.

The A horizon has hue of 7.5YR or 10YR, value of 4 or

5 when moist and 6 or 7 when dry, and chroma of 3 or 4

when moist and dry.

The C horizon has hue of 10YR to 5Y, value of 3 to 5

when moist and 5 to 7 when dry, and chroma of 2 to 4

when moist and dry. It is very channery or extremely

channery sand or loamy sand.

Wollard Series

The Wollard series consists of moderately deep,

moderately well drained soils formed in a mixture of

volcanic ash, colluvium, and slope alluvium over glacial till

dominated by phyllite. These soils are on mountain back

slopes. Slopes are 30 to 60 percent. The average annual

precipitation is 75 to 85 inches, and the mean annual air

temperature is about 42 degrees F.

These soils are fine-loamy, mixed, Typic Cryorthods.

Typical pedon of Wollard gravelly silt loam, 30 to 60

percent slopes, 6 miles east of Acme, 300 feet south and

100 feet west of the northeast corner of sec. 18, T. 37 N.,

R. 6 E.

Oa-7 to 6 inches; undecomposed needles, leaves, and

twigs.

Oi-6 inches to 0; decomposed needles, leaves, and

twigs; many very fine and fine and few medium

roots.

E-0 to 1 inch; brown (7.5YR 5/2) gravelly loam, pinkish

gray (7.5YR 7/2) dry; massive; slightly hard, friable,

slightly sticky and slightly plastic; weakly smeary; many

very fine roots; many very fine irregular pores; about 15

percent pebbles; NaF pH 10.0; extremely acid; abrupt

smooth boundary.

Bhs-1 to 2 inches; yellowish brown (10YR 5/6) gravelly silt

loam, brownish yellow (10YR 6/6) dry; dusky red

(2.5YR 3/2) organic stains, reddish brown (2.5YR 4/4)

dry; moderate medium subangular blocky structure;

slightly hard, very firm, nonsticky and nonplastic;

weakly smeary; many very fine roots; many very fine

irregular pores; about 15 percent pebbles; NaF pH

11.0; very strongly acid; abrupt smooth boundary.

Bs-2 to 9 inches; yellowish brown (10YR 5/6) gravelly silt

loam, brownish yellow (10YR 6/6) dry; weak medium

subangular blocky structure; slightly hard, firm, slightly

sticky and slightly plastic; common very fine and few

fine roots; many very fine irregular pores; about 25

percent pebbles; NaF pH 12.0; strongly acid; clear

smooth boundary.

C-9 to 30 inches; light brownish gray (2.5Y 6/2) gravelly

loam, white (2.5Y 8/2) dry; massive; slightly hard,

friable, slightly sticky and slightly plastic;

weakly smeary; few very fine roots; many very fine

irregular pores; about 30 percent pebbles; NaF pH

11.0; strongly acid; clear smooth boundary.

2Cd-30 to 60 inches; light brownish gray (2.5Y 6/2),

dense glacial till that breaks to gravelly loam, white

(2.5Y 8/2) dry; massive; hard, very firm, slightly sticky

and slightly plastic; about 30 percent pebbles; NaF pH

11.0; strongly acid.

The depth to dense, compact glacial till is 20 to 40

inches. The content of rock fragments in the particle-size

control section ranges from 15 to 35 percent pebbles and

channers.

The E horizon has hue of 7.5YR or 10YR, value of 4 or 5

when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry.

The Bhs and Bs horizons have hue of 7.5YR or 10YR,

value of 4 or 5 when moist and 5 or 6 when dry, and

chroma of 4 to 6 when moist and dry. They are gravelly

loam or gravelly silt loam.

The C and 2Cd horizons have hue of 2.5Y or 5Y, value

of 4 to 6 when moist and 6 to 8 when dry, and chroma of

2 to 4 when moist and dry. The C horizon is gravelly

loam or gravelly clay loam, and the 2Cd horizon is dense

glacial till that breaks to the same textures.

Woodlyn Series

The Woodlyn series consists of shallow, poorly drained

soils formed in a mixture of loess and volcanic ash over

glacial outwash. These soils are on outwash terraces and

outwash plains. Slopes are 0 to 2 percent. The average

annual precipitation is 35 to 55 inches, and the mean

annual air temperature is about 50 degrees F.

These soils are loamy, mixed, mesic, ortstein,

shallow Typic Sideraquods.

Typical pedon of Woodlyn loam, in an area of EdmondsWoodlyn loams, drained, 0 to 2 percent slopes; 4 miles

north of Ferndale, 2,400 feet north and 1,500 feet west of

the southeast corner of sec. 6, T. 39 N., R. 2 E.

Ap-0 to 9 inches; dark brown (7.5YR 3/2) loam, light

brownish gray (10YR 6/2) dry; weak fine granular and

weak medium subangular blocky structure; soft, very

friable, slightly sticky and slightly plastic; many very

fine and fine roots; many very fine irregular pores; NaF

pH 9.4; strongly acid; clear smooth boundary.

E-9 to 12 inches; dark grayish brown (10YR 4/2) and

grayish brown (10YR 5/2) loam, light brownish gray

(10YR 6/2) dry; few fine distinct yellowish brown
(10YR 5/6) mottles, brownish yellow (10YR 6/6) dry;

weak medium subangular blocky structure parting to

weak fine granular; soft, very friable, slightly sticky and

slightly plastic; many very fine roots; many very fine

irregular pores; NaF pH 10.0; moderately acid; abrupt

smooth boundary.

2Bsm1-12 to 17 inches; dark grayish brown (10YR

4/2), indurated ortstein pan that breaks to loamy sand,

light brownish gray (10YR 6/2) dry; many coarse

prominent dark brown (7.5YR 4/4) mottles, reddish

yellow (7.5YR 6/6) dry; massive; extremely hard,

extremely firm, nonsticky and nonplastic; few very fine

roots in cracks; few very fine irregular pores;

moderately acid; clear smooth boundary.

2Bsm2-17 to 25 inches; dark brown (10YR 3/3), weakly

cemented ortstein pan that breaks to loamy sand, pale

brown (10YR 6/3) dry; few fine distinct yellowish brown

(10YR 5/6) mottles, brownish yellow (10YR 6/6) dry;

massive; hard, firm, nonsticky and nonplastic; few very

fine irregular pores; moderately acid; abrupt smooth

boundary.

2C1-25 to 38 inches; coarse sand that is dominantly

brown (10YR 5/3) but is variegated; white (10YR 8/2)

dry; single grain; loose; many very fine irregular pores;

moderately acid; clear smooth boundary.

2C2-38 to 60 inches; coarse sand that is dominantly olive

gray (5Y 4/2) but is variegated; light gray (5Y 7/1) dry;

single grain; loose; many very fine irregular pores;

moderately acid.

The depth to the strongly cemented ortstein pan is 10 to

14 inches. The particle-size control section has 10 to 18

percent clay by weighted average.

The Ap horizon has hue of 7.5YR or 10YR, value of 3 or

4 when moist and 6 or 7 when dry, and chroma of 1 to 3

when moist and dry. Pedons in uncultivated areas have

an A horizon 3 to 7 inches thick, similar to the Ap horizon.

The E horizon has hue of 7.5YR or 10YR, value of 3 to

5 when moist and 6 or 7 when dry, and chroma of 1 or 2

when moist and dry. It is loam or sandy loam.

The 2Bsm1 horizon has hue of 7.5YR or 10YR, value of

3 to 5 when moist and 5 to 7 when dry, and chroma of 2 to

4 when moist and dry. It is a strongly cemented ortstein

pan that breaks to loamy sand or sand. It is very hard or

extremely hard when dry and very firm or extremely firm

when moist.

The 2Bsm2 horizon has hue of 7.5YR or 10YR, value of

3 to 5 when moist and 5 to 7 when dry, and chroma of 2 to

4 when moist and dry. It is continuously weakly cemented

and is slightly hard or hard. It breaks to loamy sand or

sand. Some pedons have a 213s horizon

that has 15 to 35 percent ortstein concretions 0.25 inch to

2 inches in diameter. This horizon is slightly hard or hard.

The 2C horizon has hue of 10YR, 2.5Y, or 5Y, value of 3

or 4 when moist and 6 or 7 when dry, and chroma of 2 or

3 when moist and dry.' It is coarse sand or sand.

Yelm Series

The Yelm series consists of very deep, moderately well

drained soils formed in a mixture of volcanic ash and loess

over glaciofluvial deposits. These soils are on terraces.

Slopes are 0 to 8 percent. The mean annual precipitation is

30 to 50 inches, and the mean annual air temperature is

about 50 degrees F.

These soils are coarse-loamy, mixed, mesic Aquic

Haplorthods.

Typical pedon of Yelm loam, 3 to 8 percent slopes, 4

miles northwest of Ferndale, 2,600 feet north and 1,000

feet east of the southwest corner of sec. 1, T. 39 N., R. 1

E.

Ap-0 to 8 inches; dark brown (7.5YR 3/2) loam, yellowish

brown (10YR 5/4) dry; weak fine granular structure; soft,

very friable, nonsticky and nonplastic; weakly smeary;

many very fine and fine and common medium roots;

many very fine irregular pores; NaF pH 10.5; slightly

acid; clear smooth boundary.

Bs1-8 to 15 inches; dark brown (7.5YR 4/4) loam, light

brown (7.5YR 6/4) dry; weak medium subangular

blocky structure; soft, very friable, nonsticky and

nonplastic; weakly smeary; many very fine and fine

roots; many very fine irregular pores; NaF pH 11.0;

slightly acid; clear smooth boundary.

Bs2-15 to 30 inches; dark yellowish brown (10YR 4/4)

loam, light yellowish brown (10YR 6/4) dry; weak

medium subangular blocky structure; soft, very friable,

nonsticky and nonplastic; weakly smeary; many very

fine and common fine roots; many very fine irregular

pores; NaF pH 11.5; slightly acid; clear smooth

boundary.

BC-30 to 36 inches; dark yellowish brown (10YR 4/4) and

yellowish brown (10YR 5/4) loam, light yellowish brown

(10YR 6/4) and very pale brown (10YR 7/3) dry;

common medium distinct strong brown (7.5YR 5/6)

mottles, yellowish brown (10YR 5/6) dry; weak medium

subangular blocky structure; soft, very friable, nonsticky

and nonplastic; weakly smeary; common very fine and

fine roots; many very fine irregular pores; NaF pH 11.0;

moderately acid; clear smooth boundary.
2C1-36 to 50 inches; light brownish gray (2.5Y 6/2)

and pale brown (10YR 6/3) very fine sandy loam,

light gray (2.5Y 7/2) and very pale brown (10YR 7/4)

dry; many medium prominent yellowish red (5YR

5/8) mottles, strong brown (7.5YR 5/8) dry;

weak medium subangular blocky structure; soft, very

friable, nonsticky and nonplastic; few very fine roots;

many very fine irregular pores; NaF pH 11.0;

moderately acid; clear smooth boundary.

2C2-50 to 60 inches; light gray (2.5Y 7/2) and light olive

brown (2.5Y 5/4) very fine sandy loam, white (2.5Y

8/2) and pale yellow (2.5Y 7/4) dry; massive; slightly

hard, friable, nonsticky and nonplastic; few very fine

roots; many very fine irregular pores; NaF pH 10.5;

slightly acid.

The thickness of the part of the profile influenced by

volcanic ash and the depth to the 2C horizon range from

20 to 40 inches.

The A horizon has hue of 7.5YR or 10YR, value of 3 or 4

when moist and 4 or 5 when dry, and chroma of 2 to 4

when moist and dry.

The Bs horizon has hue of 7.5YR or 10YR, value of 3

to 5 when moist and 5 to 7 when dry, and chroma of 3 or

4 when moist and dry. It is loam, fine sandy loam, or very

fine sandy loam.

The 2C horizon has hue of 2.5Y or 5Y, value of 4 to 7

when moist and 5 to 8 when dry, and chroma of 2 to 4

when moist and dry. It is loam, fine sandy loam, or very

fine sandy loam or is stratified loamy sand, sandy loam,

and silt loam.
Formation of the Soils

Soil is a dynamic, natural, three-dimensional body

synthesized from mineral and organic materials that exist

on the surface of the Earth. It provides air, water, root

anchorage, and nutrients for plants.

Soil is a fundamental part of the ecosystem that is

formed through the integrated effect of physical, biological,

and chemical weathering of geological materials acting over

time. Individual soils are characterized by their vertical

sequence of layers, or horizons, which vary in such

properties as color, texture, acidity, and the amount of rock

fragments. Soils differ in their appearance, productivity, and

management requirements in different locations and even

over short distances. They can be distinguished by

differences in the sequence and properties of their

horizons. The characteristics and properties of the soil at

any given place are determined by the interaction of five

factors: the physical, chemical, and mineralogical

composition of the parent material; the climatic conditions

acting on the parent material during the evolution of the

soil; the topography, or relief, of the landscape; the plant

and animal life within and on the surface of the soil; and

the age of the soil, or the length of time that the climate,

topography, and biota have acted on the parent material.

The five factors are interdependent; the combined action

of these forces results in soil formation, although one or

two of them often predominate at a particular site. Climate

and biota, particularly vegetation, are the active forces of

soil formation. A particular set of soil-forming factors gives

rise to a unique soil profile; as any one factor changes, so

does the soil. Horizons are continually forming and

evolving in response to environmental factors.

In the first part of this section, climate, living organisms,

and topography are described separately. The factors of

parent material and time are described in the sections

"Geomorphic Surfaces" and "Geomorphic Unit."

Many of the soils in the survey area are very similar to

soils in the Lower Fraser Valley in British Columbia (16,

17) . The laboratory data for those soils and

additional information about their formation and

characteristics are available (25, 26, 27).

Climate

Climate has a strong influence on soil formation.

Temperature and moisture greatly influence the kind and

productivity of vegetation, the activity of microorganisms,

and the rate at which organic matter decomposes and

minerals weather. They also influence water movement

through the soil and thus indirectly control the rate of

removal (leaching) of soluble material from some soil

horizons; the chemical state of certain elements, such as

iron and manganese; and the rate of translocation and

accumulation of materials into other horizons.

Climate also is largely responsible for the amount and

intensity of soil erosion from uplands and for the

deposition of soil material on lowlands and flood plains.

Wind patterns and geographic distribution of rainfall affect

the deposition pattern of eolian material.

Precipitation in the survey area occurs mostly between

October and May. The amount and distribution of

precipitation in the survey area is similar to that of soils in

a xeric moisture regime. Soils on the poorly drained

bottom land and in depressions on uplands are in an aquic

moisture regime because high ground-water levels keep

the soil saturated for prolonged periods. Most soils that

receive more than 70 inches of precipitation in a year are

moist throughout the year or are dry for less than 45

consecutive days; therefore, they have a udic moisture

regime (18).

A climatic sequence of soils formed in a mixture of

volcanic ash, loess, and phyllite colluvium shows the

effects of climate on the amount of leaching and on the

accumulation of organic matter, both increase with

increasing elevation (30). While the other soil-forming

factors are relatively constant (except as climate influences

vegetation), the climate varies. For example, in areas of

Squires, Rinker, Springsteen, Crinker, and Hinker soils, the

mean annual temperature ranges from 48 to 51 degrees F

and the mean annual precipitation ranges from 45 to 100

inches.
In the following paragraphs, the three general climatic

zones of the survey area are described briefly. These

zones are characterized by differences in the kind and

amount of precipitation and in the mean annual air

temperature. These differences, in turn, affect the type and

abundance of vegetation that occurs and the amount of

organic matter produced.

Climatic Zone 1 includes general soil map units 1

through 11. Precipitation in this zone occurs mostly as rain

between October and May. It ranges from 30 to 75 inches

annually. Snow falls sporadically between December and

February. Because the average annual soil temperature

ranges from 47 to 50 degrees F, the soils in this zone are in

the mesic temperature regime (43). During summer, the

weather is warm and dry, and the soils are dry for a long

period. As a result, the soils are in the xeric moisture

regime. During winter, the weather is cool and moist and

the soils are moist. Freezing occurs in the surface layer of

most soils, particularly those which are bare.

Most of the better drained soils are Typic Haplorthods.

They have a light colored surface layer (ochric epipedon)

and an accumulation of iron and aluminum and some

organic matter in the subsoil (spodic horizon). Typically, the

surface layer of poorly drained soils in zone 1 has

accumulated enough organic matter to qualify as an umbric

or mollic epipedon. Some soils have an accumulation of

clay in the subsoil. The soils in this zone are mainly Typic

Umbraqualfs or Typic Argiaquolls. The major exceptions are

Edmonds and Woodlyn soils, which have a subsoil that is

cemented with iron and that qualifies as a spodic horizon.

The Edmonds and Woodlyn soils are Typic Sideraquods.

Climatic Zone 2 includes general map units 12 and 13.

The annual precipitation ranges from 45 to 85 inches.

Snowfall dominates the precipitation from December

through February, and the snow cover generally lasts

through March. Because the average annual soil

temperature ranges from 44 to 47 degrees F, the soils in

this zone are in the frigid temperature regime. During

summer, the weather is warm and dry and the soil

temperature is above 47 degrees F. The soils are dry for

shorter periods than the soils in zone 1. Low soil

temperatures in winter reduce biological and chemical

activity. Freezing is common in these soils.

Most of the soils in zone 2 are Typic Haplorthods, which

have a light colored surface horizon (ochric epipedon) and

a subsoil that has accumulated iron, aluminum, and organic

matter (spodic horizon). Many of the soils have a leached

surface layer (albic horizon) above the spodic horizon.

Climatic Zone 3 includes general soil map unit 14.

The annual precipitation, which is dominantly snow,

ranges from 75 to 105 inches. The snow cover can last

through May. The upper part of the soil is very cold or

frozen for as long as 6 months. In this zone soils tend to

develop slowly because the cold temperatures suspend or

significantly reduce the extent of biological and chemical

activity. Frost action is common.

Summers are short, cool, and moist, and the soils never

warm above 47 degrees F. Because the average annual

temperature ranges from 40 to 46 degrees F, the soils in

this zone are in the cryic temperature regime.

The soils in zone 3 are dominantly Cryorthods that have

a thick organic mat, a leached surface layer (albic horizon),

and an accumulation of translocated organic matter, iron,

and aluminum in the subsoil (spodic horizon). Shuksan,

Hinker, and Hartnit soils, which are Humic Cryorthods, are

in the colder, wetter part of the zone. As a result, they have

a thicker organic layer and a larger accumulation of organic

matter in the subsoil than Getchell, Springsteen, and

Wollard soils which are Typic Cryorthods. The Getchell,

Springsteen, and Wollard soils are in the part of the zone

that receives less precipitation and has higher

temperatures. All of the soils in zone 3 have low bulk

density, low percent base saturation, and high available

water capacity relative to clay content.

Living Organisms

Plants, micro-organisms, and animals are active forces

in soil formation. Plants draw moisture and nutrients from

the soil and improve aeration, soil structure, and

permeability. They also intercept rainfall and mitigate its

impact, thus helping to control runoff and erosion by

stabilizing the soil. The remains of dead plants replenish

the content of organic matter in the soil.

If moisture and temperatures are adequate, the soil

becomes the medium in which simple forms of life grow

and reproduce. Micro-organisms, such as fungi and

bacteria, improve soil fertility by helping in the

decomposition of organic matter and conversion of nutrients

in plant litter to forms that are once again available to

plants (7). Soils that are wet, cold, or both inhibit the growth

of these aerobic soil fauna; as a result, organic matter

accumulates more rapidly in them than in dry, warm soils.

Wet soils, such as Bellingham soils, and cold soils, such as

Shuksan soils, have a high content of organic matter.

Small animals, earthworms, and insects influence the

formation of soil by mixing organic matter into the mineral

soil material and by breaking down plant remains and

accelerating the decomposition of the organic matter. Small

animals burrow into the soil and
mix the layers. Earthworms and small vertebrates feed on

the organic matter in the upper few inches of the soil

material. They slowly, but continually, mix the soil material

and sometimes alter its chemistry. Except at the higher

elevations, the conditions in the survey area are favorable

for most organisms to function.

Organic matter in the soil is the main source of nitrogen

for plant growth and of organic acids that promote leaching

of soils. High levels of organic matter in soils are indicated

by black or dark brown colors. Applying manure, mixing

organic matter into the surface layer of cropland, and

converting forest land to pasture help to increase the

organic matter content and darken the surface layer in

soils, such as in the Whatcom, Edmonds, and Hale soils.

Organic soils, such as Pangborn, Shalcar, and Fishtrap

soils, formed in bogs in the accumulated remains of watertolerant plants, such as sedges, rushes, and mosses.

These deposits are highly decomposed sapric material

(muck), particularly where drained. Undrained areas contain

less-decomposed hemic material (36). Drainage increases

aeration and soil temperature, thereby improving the

conditions for microbial activity and resulting in a greater

decomposition of the organic material. Drainage causes

the surface to subside and results in soil loss unless the

soil is kept moist (7).

In the survey area, soils have formed under three major

types of plant cover. In some places soils in the aquic soil

moisture regime had native vegetation consisting of mixed

conifers and hardwoods that were tolerant to high water

levels. In other places the vegetation was mainly sedges,

rushes, and other water-tolerant plants. Labounty,

Whitehorn, and Everson soils are examples of soils in this

regime. They have a dark surface horizon that has a high

content of organic matter and a gleyed, mottled B horizon

that is a result of the low level of oxygen.

In the area that receives a lower amount of

precipitation, the soils are moist in winter and dry in

summer. This area is dominated by Douglas fir and

western hemlock in the overstory and by a variety of

shrubs in the undergrowth (15). Everett, Chuckanut, Oakes,

and Montborne soils are examples of soils in this area.

They have a lighter colored or thinner surface layer than

that of the soils in the aquic moisture regime. Their subsoil

is also more leached and is redder because of greater

aeration. Plants on soils in this area are subject to varying

degrees of moisture stress in summer.

In the udic moisture regime, which receives more than

70 inches precipitation, the soils are moist almost year

round and are cold because of higher elevation. Kindy,

Saar, Kulshan, and Edfro soils are examples of

soils in this regime. The large amounts of organic matter,

organic acids, and the leaching of bases have produced

high acidity in these soils. Pacific silver fir, western

hemlock, and mountain hemlock dominate the vegetation

on these soils.

The major human activities that impact the soils in the

survey area are urbanization, channelization of rivers, the

installation of drainage systems, mining operations, timber

harvesting, and timber regeneration. Timber harvesting

mixes the duff and forest debris with the surface soil.

Clearcutting, with or without burning, allows forbs, shrubs,

and ferns to invade and grow and thus to alter the

distribution of organic matter in the soils (15).

Topography

Topography is a primary factor in soil variation (21). It

includes relief, aspect, elevation, and drainage and largely

determines the amount of water distribution and movement

in the soil and the stability of soil material. Runoff increases

with the steepness of slope; thus, deposition of soil is

greater on toe slopes and valleys below steep slopes than

it is on ridges, uplands, or broad, flat plains. Vegetation

stabilizes the soil on slopes, helps to control erosion, and

increases the rate of soil development. When soils are laid

bare by timber harvesting or agriculture, the potential for

erosion increases, particularly during periods of heavy

rainfall. Sheet erosion mainly carries away surface soil. Rill

and gully erosion can cut into the subsoil and substratum.

Mass wasting on steep slopes can remove all soil above

the regolith. It is particularly common on Andic Xerochrepts,

Andic Cryochrepts, and Typic Cryorthods that have 60 to 90

percent slopes and on soils, such as Sehome, Cupples,

Kindy, and Saar soils, that have the 45 to 60 percent slopes

and are underlain by glacial till.

Aspect, or slope orientation, can play an important role in

soil formation through its influence on available water (8). It

can affect the distribution of organic carbon in the soil, the

presence or absence of an E horizon, pH, and percent

exchangeable bases (5). Effective precipitation is less on

south- and west-facing slopes than on north- and eastfacing slopes. Soil temperatures are higher on south- and

west-facing aspects. These higher temperatures cause

snow to melt and soils to warm sooner. As a result, the

chance for moisture stress increases and plant and animal

communities occur at higher elevations than on north- and

east-facing aspects. On north-facing aspects in Whatcom

County, the cryic temperature regime begins at about 1,800

feet; whereas on south-facing slopes, it begins at about

2,500. Generally, as elevation increases, snow cover and

precipitation increase and
temperature and length of the frost-free season

decrease.

Much of the nonmountainous part of the survey area

consists of broad, nearly level glacial outwash and alluvial

terraces and of rolling glaciomarine drift plains and

proglacial lacustrine terraces that have slopes of less than

8 percent. As a result, differences in the relief of even a

few feet can result in major differences in the level of the

water table and thus in drainage class and soil formation.

Differences in relief result in the removal of runoff from

higher parts of the landscape and the collection of water in

swales, basins, and depressions. In the survey area,

drainage is one of the most important factors in the

distribution of soils and vegetation. Soils have differing

properties as a result of differences in relief. For example,

the Whatcom-Labounty and Skipopa-Bellingham catenas

formed in a mixture of volcanic ash,

 and loess over

glaciomarine drift and volcanic ash and loess over

glaciolacustrine sediments, respectively. The moderately

well drained Whatcom and the somewhat poorly drained

Skipopa soils are in the higher landscape positions. They

have a dark brown or dark yellowish brown surface layer

and subsoil. They have low bulk density and are moderately

permeable (30, 32). The poorly drained Labounty and

Bellingham soils have a dark brown to black surface layer

that has a high content of organic matter and a gray,

mottled subsoil that has a low content of organic matter

and is high in bulk density. They are moderately slowly

permeable or slowly permeable. Their subsoil can be hard

and impermeable. The Labounty and Bellingham soils are

ponded in winter unless the soils are drained, whereas the

water table in Whatcom and Skipopa soils remains below a

depth of 1 foot. The Whatcom and Skipopa soils support

Douglas fir and a diverse ground cover. The Labounty and

Bellingham soils support red alder, western redcedar, and

more limited, moisture-tolerant types of ground cover.

Other soil topographic transacts of this type are the

Kickerville-Clipper, Birchbay-Whitehorn, Mt. Vernon-Briscot,

and Lynden-Laxton-Tromp-Edmonds-Woodlyn catenas.

Soils on bottom land in the survey area formed in

alluvium deposited by the runoff from surrounding uplands

and from the floodwaters of adjacent streams and rivers

that carried material down valleys from the higher

elevations. The duration and frequency of flooding, the

particle-size and stratification of the deposits, and the

ability of the soils to drain excess water are the three

conditions responsible for differences in soil development

and land use on bottom land. The well drained Puyallup

and the moderately well drained Mt. Vernon soils occur on

levees. Because of their higher position on the landscape,

they are less

seriously affected by flooding than the poorly drained

Briscot, Oridia, Sumas, and Puget soils on the flood

plain and the Eliza and Tacoma soils on the delta.

Topography, partly by its effect on vegetation, has a

major influence on the weathering of the parent material

and on the mineralogy of a soil (40). This effect can be

seen in the alpine (6) as well as the nonmountainous parts

of the survey area (32). The effects of podzolization and

volcanic ash can be difficult to distinguish (37).

Geomorphic Surfaces

The geomorphology and soils of the survey area reflect

a sequence of depositional and erosional events that are

the result of glacial and fluvial processes (17). Each

sequence of erosion and deposition represents an episode

in time that can be delineated as a set of geomorphic

surfaces (31).

The soils associated with a particular geomorphic

surface are recognized primarily by contrasts in the age and

texture of the parent material.

The soils of the survey area vary considerably in age.

Soil formation in unconsolidated material begins when the

last sediments are deposited and the surface stabilizes to

vegetation. It begins in bedrock or dense glacial till when

that material has weathered to a permeable state. Soil

material is in a dynamic state of formation. It is continuously

being eroded and deposited on most sites.

Time is unique among the factors of soil formation

because its influence is solely to allow the topography,

biota, and climate to act on the parent material and to

change that parent material into soil. Generally, the

younger the soil, the more influential the parent material.

As age increases, soil horizons form and become more

distinctive.

None of the soils in the survey area have significant

accumulations of translocated organics, clay, sodium, or

carbonates in the subsoil. The annual precipitation of 30 to

60 inches has leached most of the soluble materials below

the zone of observation. Whatcom soils have some

carbonates. These carbonates are present in the marine

sediment and are difficult to leach because of the slow

permeability in the soils. The soils also have some

argillans.

Structure is weak in most of the soils. The strongest

structure in the subsoil is in the soils that have a high clay

content, such as Bellingham soils, and in the Spodosols

that have iron cementation, such as Edmonds and Woodlyn

soils.

The major distinctive horizons in the survey area are the

E and upper Bsm horizons in the poorly drained

Spodosols and the Ap and Bg horizons in cultivated,
poorly drained soils. The well drained and moderately

well drained soils on the two older surfaces have silt

pellets and cracked coatings in the B horizon.

There are four geomorphic surfaces in the survey

area. They are described as follows:

Surface 1. This surface consists of the lower, active

flood plain of the Nooksack River. It is the depositional and

erosional environment of the river channels and associated

point bars and channel fillings. It is generally underlain by

coarse alluvium and is subject to annual flooding. The

deposits are pebbles, sand, and silt. The landscape

configuration is not stable and changes rapidly as a result

of water cutting new channels, abandoning older channels,

and moving alluvial deposits downstream.

The age of the surface is late Holocene. Elevation

ranges from sea level to 165 feet above sea level. Slopes

are 0 to 3 percent. The principal soils on this surface are

the Mt. Vernon soils, which are very deep, moderately well

drained, and composed of unweathered sand with an

admixture of volcanic ash in the upper part. Mt. Vernon

soils, which are Fluvaquentic Haploxerolls, have no

diagnostic features other than a mollic epipedon (43).

Riverwash also is a major component of this surface.

Alluvial fans and coastal beach deposits are included in

this unit. Some organic deposits occur in the quiet

backwater areas. The parent material of the fans depends

on the lithology at the source of the debris. Wickersham

and Wiseman soils formed in phyllite alluvium, whereas

Kline soils formed in a variety of materials. Neptune and

Hovde soils are inextensive soils that formed in gravelly

marine deposits having varying degrees of incorporated

seashells.

Surface 2. This surface consists of the higher of the two

flood plains and includes the levees, the valley flat, and the

modern delta of the Nooksack River. The deposits

generally are stratified sand, silt, and clay. The alluvium is

derived from a variety of rocks but is dominated by

andesite and metasedimentary material (12). Alluvial fans

and coastal beach deposits are included in this surface.

Some organic deposits occur in former quiet backwater

areas. Elevation ranges from sea level to 200 feet above

sea level. Slopes are dominantly 0 to 2 percent but are as

steep as 8 percent on alluvial fans.

Deposition started on this surface after the Sumas Stade

of the Fraser Glaciation about 10,000 years before the

present. No properties associated with volcanic ash are

evident in the soils. Since the ash in the western part of

the survey area originates from Mount Mazama (12, 24),

the lack of Mazama ash within this surface indicates that

the surface is younger than 6,600 years. This surface is

probably middle to late Holocene.

Soils of this surface have few prominent morphological

features; they are differentiated mainly by the texture of the

parent material. Most of the soils have a fluctuating water

table, as indicated by mottling in the underlying material

within a depth of 20 inches. The soils on the river terraces

and flood plains are very deep, are nearly level, and have a

mollic epipedon. The moderately well drained Mt. Vernon

soils, which are Fluventic Haploxerolls, are examples of

these soils.

The soils on the delta are very deep, are very poorly

drained, and contain sulfidic material. The principal soils

are the Eliza and Tacoma soils, which are subject to salt

intrusion as a result of their proximity to the sea. The Eliza

and Tacoma soils are Sulfic Fluvaquents.

The soils on the valley flat are very deep, poorly drained

Aeric Fluvaquents. They include Briscot and Oridia soils.

These soils and those on the delta have no diagnostic

horizon other than an ochric epipedon.

Surface 3. This surface is dominantly outwash terraces

but also includes proglacial lacustrine terraces. The

outwash terraces consist of sand with various amounts of

gravel. Depressions in the outwash terraces, both channels

and kettles, commonly contain organic deposits. Lakebeds

and low-relief, abandoned channels that are filled with

organic material are typical of surfaces of this age in

western Oregon (31) and south-central Washington (19),

although the latter did not develop in glacial material. The

glaciolacustrine deposits consist of silt and clay, which are

distinctly varved in some areas. A thin layer of eolian

material, which includes volcanic ash, mantles this surface

(3).

Surface 3 is the oldest surface related to the present

drainage system. The ancient drainage pattern parallels

that of the modern flood plain indicating that the Nooksack

River is a remnant of the preexisting glacial drainage

system. The ability of the proglacial streams to carry

material was greater than that of the modern Nooksack

River, and the valley was broader, as is indicated by the

deposits, which are coarser and more extensive than

modern alluvial material. The texture of the soils reflects

this difference.

The pro-glacial streams deposited material that has a

high content of rock fragments. Kickerville, Barnhardt, and

Clipper soils formed in this material. The slower moving

waters deposited stratified sands and some silts that have

a low content of rock fragments. These sediments were

later reworked by wind. Lynnwood, Lynden, Laxton, Tromp,

Hale, Edmonds, and Woodlyn soils formed in these

deposits. The admixture of silty eolian deposits and organic

matter into these soils has markedly increased their fertility

(16). Elevation ranges from 50 to 300 feet. Slopes range

from 0 to 15 percent.

Carbon-14 dates obtained from the base of the organic

deposits range from 9,920 years (plus or minus
760) to 9,300 years (plus or minus 250) before the present

(3, 12). The outwash and glaciolacustrine deposits are

slightly older, and the surface is slightly younger,

corresponding to late Pleistocene. Deposition occurred

during the Sumas Stade of the Fraser Glaciation. The

organic soils commonly contain strata of volcanic ash (36)

from the eruption of Mount Mazama, as do soils of similar

age in other areas of the Pacific Northwest (19, 31).

The soils on the outwash terraces are very deep to

shallow, somewhat excessively drained to poorly drained,

and nearly level to gently sloping. The lower part of the

profile in these soils is sandy and contains 0 to 60 percent

coarse fragments. The upper part of the profile of most of

these soils formed in eolian deposits that include volcanic

ash. Each of the soils on this surface has a spodic horizon.

The principal soils are the well drained Lynden and

Kickerville soils, which are Typic Haplorthods, and the

moderately well drained Tromp and somewhat poorly

drained Hale soils, which are Aquic Haplorthods. Also

included are the poorly drained Edmonds and Woodlyn

soils, which are Typic Sideraquods. A continuous hardpan

(ortstein layer) that is strongly cemented with iron has

developed within a depth of 20 inches in the Woodlyn

soils. This layer, which formed from the deposition of iron

at the water table, is fragmented in the Edmonds soils.

Upon glacial recession, meltwater flow decreased.

Abandoned outwash channels and, to a lesser extent,

kettles and other depressions on the flood plains supported

wetland plants, such as rushes, sedges, and some woody

plants, in the stagnant water (36). When the plant material

died, it accumulated and became the parent material for the

very deep, very poorly drained, nearly level Pangborn soils,

which are Typic Medisaprists, and Shalcar and Fishtrap

soils, both of which are Terric Medisaprists. The soils on

the glaciolacustrine terraces are very deep, somewhat

poorly drained and poorly drained, and nearly level to

gently sloping. They are on ridge-swale topography.

Skipopa soils, which are Aqualfic Haplorthods, are on the

ridges. They have a silty eolian mantle over a clayey

substratum. They have a spodic horizon and an argillic

horizon. Bellingham soils, which are Mollic Haplaquepts,

are in the swales. They have a mollic epipedon and an

argillic horizon and are clayey throughout the control

section.

Surface 4. This surface consists of glaciomarine deposits

having an eolian mantle that includes volcanic ash (32).

The rolling topography reflects the deposition from melting

ice of debris that ranges in size from clay particles to

boulders. In the western part of the survey area, poorly

sorted glaciofluvial material as much as 24 inches thick lies

between the eolian mantle and the

glaciomarine deposits. Elevation ranges from 65 to 400

feet. Slopes range from 0 to 60 percent.

The age of this surface has been determined from the

dating of fossil shells in the glaciomarine deposits. Dates

range from 12,090 years (plus or minus 350) to 10,370

years (plus or minus 300) before the present (3, 12). The

material was deposited in the late Pleistocene during the

Everson Interstade of the Fraser Glaciation prior to the

inception of the Sumas Stade. Dates from marine terraces

and peat bogs overlying these deposits show that the area

was rapidly uplifted isostatically during this time (11).

On glaciomarine drift plains not overlaid by the

glaciofluvial materials, the soils are very deep, moderately

well drained and poorly drained, and nearly level to steep.

Whatcom soils, which are Aqualfic Haplorthods, have a

spodic horizon and an argillic horizon and are in the

higher, steeper part of the landscape. Labounty soils,

which are Typic Umbraqualfs, have an umbric epipedon

and an argillic horizon and are in the lower part.

The soils with interbedded glaciofluvial deposits are very

deep, moderately well drained and poorly drained, and

nearly level to gently sloping. Birchbay soils, which are

Typic Haplorthods, and Whitehorn soils, which are Typic

Umbraqualfs, are similar in morphology and landscape

position to Whatcom and Labounty soils, respectively, but

have coarser textures in the upper part of the substratum.

Although clay films in the Whatcom, Labounty, Skipopa,

Bellingham, and Whitehorn soils are uncommon,

micromorphological evidence in the form of argillans

indicates the development of an argillic horizon. The

classification of the spodic horizon on surfaces 3 and 4 is

based on the discovery by the USDA's Soil Survey

Investigations Staff of silt-sized pellets and some cracked

coatings in the B horizon. The soils do not meet the

chemical criteria for a spodic horizon.

Geomorphic Unit

The geomorphic unit has no age connotation; therefore,

it is not considered a geomorphic surface. The topography

is completely dissected and predominantly steeply sloping.

Slopes are as much as 90 percent. Elevation ranges from

500 to 5,000 feet. The steep, broken topography may join

any other surface, or it may make up large areas of

mountainous terrain so thoroughly dissected that a

geomorphic surface is not recognized. Erosion is active in

much of the unit, and in some areas mass movement is

evident. In some areas, however, occasional remnants of

some older geomorphic surfaces are present. Many soils
contain volcanic ash and may be as old as surface 4;

adjacent soils with active erosion are as young as surface

1. The variability in age makes this geomorphic unit useful

in mapping areas of mountainous terrain.

For the most part, the rocks underlying the soils in this

unit make up the oldest formations in the survey area, but

as a rule, the soils are relatively immature and younger

than the soils in gently sloping areas. The soils formed in

colluvium, slope alluvium, and glacial till with an admixture

of eolian deposits that include volcanic ash. In the very

steep areas, erosion has been the main factor retarding

soil formation. Among the factors affecting erosion are the

length and steepness of the slope, the amount of water the

soil can absorb and retain, and the type, amount, and

duration of precipitation.

The lithology of the soils formed in the geomorphic unit

is dominantly sandstone, which underlies Nati, Chuckanut,

Revel, Welcome, and Kulshan soils; siltstone, which

underlies Comar soils; metasedimentary rocks, which

underlie Oso and Hartnit soils; and phyllite, which underlies

Squires, Rinker, Springsteen, Crinker, and Hinker soils.

Greywacke on Lummi Island, serpentine on Sumas and

Bowman Mountains, and dunite on Twin Sisters Mountain

are important in these specific areas. These rocks range in

age from pre-Jurassic to Tertiary (13).

The most distinctive bedrock in the survey area is the

dunite intrusion of the Twin Sisters Mountain. Soils that

formed in these materials are high in magnesium, are low

in calcium, and can have toxic levels of nickel, chromium,

and cobalt. The vegetation on these soils is generally

stunted because of a nutrient imbalance, calcium

deficiency, and magnesium toxicity (35). The type and vigor

of the vegetation on soils that formed in serpentine and

dunite frequently differ considerably from the vegetation on

adjacent soils that formed in different parent material (23).

The lithology of most of the glacial till is mixed. It is

derived from a variety of Canadian sources. It includes

granodiorite, andesite, chert, and metamorphic rocks (12).

Squalicum, Cupples, and Shuksan soils are representative

of the soils that formed in mixed glacial till. Some tills are

more local in origin; the soils formed in them reflect the

features of the dominant rock that

composes the till. The principal tills of local origin are

those dominated by phyllite, in which the Vanzandt,

Montborne, Wollard, and Diobsud soils formed and those

dominated by dunite, in which the Edfro and Twinsi soils

formed.

Most of the tills are dense and compacted at a depth of

2 or 3 feet from the weight and physical processes of the

overlying continental ice sheet. Some cementation also

occurs (29). The dense till perches water and restricts

rooting depth. Steep slopes are generally unstable where

the soils are saturated and a sharp discontinuity occurs

between the solum and the dense till.

The glacial till and bedrock of the mountains form a

complex mosaic, which is often so intricately mixed as to

preclude separating the soils formed from these two

parent materials. As a result, mapping extensive soil

complexes is necessary. These complexes include KindyOso, Saar-Hartnit, Klawatti-Rock outcrop, and ShuksanKulshan-Rock outcrop.

Each lithology influences the mineralogy, texture, and

available water capacity of the soils involved to different

degrees (7). Coarse-textured soils that formed in coarsetextured material, such as sandstone, have a lower

available water capacity and lower fertility than the soils

that formed in finer-textured material, such as siltstone and

phyllite. Most of the soils are modified by eolian deposits

that include volcanic ash, probably from Mt. Mazama (12,

27). The incorporation of these deposits and organic matter

into the soils dramatically increases the fertility and the

available water capacity of the soils (26).

Soils on this unit are moderately deep to very deep

and moderately well drained or well drained. The soils at

elevations of less than 1,800 feet have an ochric

epipedon and a spodic horizon and contain varying

amounts of rock fragments. They are mostly Typic

Haplorthods and include the Chuckanut, Squalicum,

Oakes, and Revel soils.

Soils above 1,800 feet are dominantly Spodosols. Soils

between elevations of 1,800 feet and 2,600 feet are Typic

Cryorthods. They include the Kindy and Getchell soils.

Above 2,600 feet the soils are typically Humic Cryorthods.

They include the Shuksan, Potchub, and Gallup soils.
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Luttmerding, Herb A. 1980. Soils of the Langley (36)

A., Ed., Advances in ecological research.

Academic Press, vol. 9, pages 255-366.

Rigg, George B. 1958. Peat resources of

Vancouver map area, soil map mosaics and

legend, Lower Frasier Valley. British Columbia

Minist. of Environ., Resour. Anal. Branch Bull. 18,

vol. 1, 40 pp., illus. (37)

Washington. State of Wash., Div. of Mines and

Geol. Bull. 44, 272 pp., illus.

Ross, G.J. 1980. Mineralogical, physical, and

(26) Luttmerding, Herb A. 1981. Soils of the Langley

chemical characteristics of amorphous

constituents in some podzolic soils from British

Vancouver map area, description of the soils.

British Columbia Minist. of Environ., Resour. Anal.

Branch Bull. 18, vol. 3, 227 pp., illus. (38)

Columbia. Can. J. Soil Sci. 60: 31-43, illus.

Snedecor, George W., and William G. Cochran.

(27) Luttmerding, Herb A. 1981. Soils of the Langley

1967. Statistical methods. Iowa State Univ. Press,

Ed. 6, 593 pp., illus.

Vancouver map area, technical data, soil profile

descriptions, and analytical data. British Columbia (39) State of Washington, Department of Natural

(28)

Minist. of Environ., Resour. Anal. Branch Bull. 18,

vol. 6, 345 pp.

McArdle, Richard E., Walter H. Meyer, and

Resources. 1978. Forest land grading procedures

handbook. State of Wash., Dep. Nat. Resour., 83

pp., illus.

Donald Bruce. 1961. The yield of Douglas fir in (40) Ugolini, F.C., and A.K. Schlichte. 1973. The effect

the Pacific Northwest. U.S. Dep. Agric. Tech. Bull.

201, 74 pp., illus.

of Holocene environmental changes on selected

western Washington soils. Soil Sci., vol. 116, 3:

218-227, illus.

(29) McKeague, J.A., and P.N. Sprout. 1975.

Cemented soils (duric horizons) in some soils of (41) United States Department of Agriculture. 1951.

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British Columbia. Can. J. Soil Sci. 55: 189-203,

illus.

Nettleton, W.D., A. Goldin, and R.J. Engel. 1986. (42)

Soil survey manual. U.S. Dep. Agric. Handb. 18,

503 pp., illus.

United States Department of Agriculture. 1961.

Differentiation of Spodosols and Andepts in a

western Washington climosequence. Soil Sci.

Soc. Am. J. 50: 987-992, illus.

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Land capability classification. U.S. Dep. Agric.

Handb. 210, 21 pp.

United States Department of Agriculture. 1975.

(31) Parsons, R.B., C.H. Balster, and A.O. Ness. Soil taxonomy: A basic system of soil

1970. Soil development and geomorphic surfaces,

Willamette Valley, Oregon. Soil Sci. Soc. Am.

Proc. 34: 485-491, illus.

classification for making and interpreting soil

surveys. Soil Conserv. Serv., U.S. Dep. Agric.

Handb. 436, 754 pp., illus.
(44) United States Department of Agriculture. 1975. (47) Wiley, Kenneth N. 1978. Site index tables for

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Trees against the wind. U.S. Dep. Agric. Bull. 5,

47 pp., illus.

United States Department of Agriculture. 1980.

western hemlock in the Pacific Northwest.

Weyerhaeuser Co. For. Res. Cent. Pap. 17, 28

pp., illus.

National forestry manual. U.S. Dep. Agric., Soil (48) Wiley, Kenneth N., and Charles J. Chambers.

(46)

Conserv. Serv., Title 190, 151 pp., illus.

Washington Division of Water Resources. 1960.

1981. Yields of natural western hemlock stands.

Wash. State Dep. Nat. Resour. Rep. 43, 79 pp.

Water resources of the Nooksack River basin and (49) Worthington, Norman P., and others. 1960.

certain adjacent streams. Water Supply Bull. 12,

187 pp., illus.

Normal yield tables for red alder. For. Serv., U.S.

Dep. Agric. Res. Pap. 36, 3 pp., illus.
Glossary

Ablation till. Loose, permeable till deposited during the

final downwasting of glacial ice. Lenses of crudely

sorted sand and gravel are common.

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.

Alluvial fan. The fanlike deposit of a stream where it

issues from a gorge upon a plain or of a tributary

stream near or at its junction with its main stream.

Alluvium. Material, such as sand, silt, or clay,

deposited on land by streams.

Animal-unit-month (AUM). The amount of forage required

by one mature cow of approximately 1,000 pounds

weight, with or without a calf, for 1 month.

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.

Aspect. Compass orientation of a slope as an inclined

elevation of the ground surface.

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:

Low .................................................................0 to 3.75

Moderate ...................................................... 3.75 to 7.5

High ........................................................ More than 7.5

Back slope. The geomorphic component that forms the

steepest inclined surface and principal element of

many hillsides. Back slopes in profile are

commonly steep, are linear, and may or may not

include cliff segments.

Basal area. The cross-sectional area of a tree bole

measured at 4.5 feet above ground level. It is

generally expressed in square feet of crosssectional area per acre.

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 cationexchange capacity.

Bedding planes. Fine strata 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.

Bisequum. Two sequences of soil horizons, each of

which consists of an illuvial horizon and the

overlying eluvial horizons.

Bottom land. The normal flood plain of a stream,

subject to flooding.

Boulders. Rock fragments larger than 2 feet (60

centimeters) in diameter.

Breaks. The steep or very steep broken land at the

border of an upland summit that is dissected by

ravines.

Breast height. An average height of 4.5 feet above the

ground surface; the point on a tree where diameter

measurements are ordinarily taken.

Brush management. Use of mechanical, chemical, or

biological methods to reduce or eliminate competition

of woody vegetation. Control of this vegetation allows

understory grasses and forbs to recover or makes

conditions favorable for reseeding. It increases forage

production and thus reduces the hazard of erosion.

Brush management may improve the habitat for some

species of wildlife.

Cable yarding. A method of moving felled trees to a

nearby central area for transport to a processing

facility. Most systems involve a drum, a pole, and
wire cables and involve the same principle as that of a

rod and reel for fishing. To reduce friction and soil

disturbance when the felled trees are yarded or reeled

in, one end of the trees generally is lifted completely

off the ground or the trees are completely suspended.

Calcareous soil. A soil containing enough calcium

carbonate (commonly combined with magnesium

carbonate) to effervesce visibly when treated with

cold, dilute hydrochloric acid.

Canopy. The leafy crown of trees or shrubs. (See

Crown.)

Canyon. A long, deep, narrow, very steep sided valley with

high, precipitous walls in an area of high local relief.

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.

Catena. A sequence, or "chain," of soils on a landscape

that formed in similar kinds of parent material but

have different characteristics as a result of

differences in relief and drainage.

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 channer.

Chemical treatment. Control of unwanted vegetation by

use of chemicals.

Chiseling. Tillage with an implement having one or more

soil-penetrating points that loosen the subsoil and

bring clods to the surface. A form of emergency tillage

to control wind erosion.

Cirque. Semicircular, concave, bowl like areas that have

steep faces primarily resulting from glacial ice and

snow abrasion.

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.

Clay skin. A thin coating of oriented clay on the surface of

a soil aggregate or lining pores or root channels.

Synonyms: clay coating, clay film.

Climax plant community. The plant community on a

given site that will be established if present

environmental conditions continue to prevail and

the site is properly managed.

Coarse fragments. Mineral or rock particles larger than 2

millimeters in diameter.

Coarse textured soil. Sand or loamy sand.

Cobbles (or cobblestones). A rounded or partly rounded

fragment of rock 3 to 10 inches (7.6 to 25

centimeters) in diameter.

Cobbly soil material. Material that is 15 to 35 percent, by

volume, rounded or partially rounded rock fragments 3

to 10 inches (7.6 to 25 centimeters) in diameter. The

content of these fragments is 35 to 60 percent in very

cobbly soil material and more than 60 percent in

extremely cobbly soil material.

Colluvium. Soil material, rock fragments, or both,

moved by creep, slide, or local wash and

deposited at the base of steep slopes.

Complex slope. Irregular or variable slope. Planning or

constructing terraces, diversions, and other watercontrol measures on a complex slope is difficult.

Complex, soil. A map unit of two or more kinds of soil or

miscellaneous areas 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 or miscellaneous

areas are somewhat similar in all areas.

Concretions. Grains, pellets, or nodules of various sizes,

shapes, and colors consisting of concentrated

compounds or cemented soil grains. The composition

of most concretions is unlike that of the surrounding

soil. Calcium carbonate and iron oxide are common

compounds in concretions.

Congeliturbate. Soil material disturbed by frost action.

Conglomerate. A coarse grained, clastic rock composed of

rounded to subangular rock fragments more than 2

millimeters in diameter. It commonly has a matrix of

sand and finer material. Conglomerate is the

consolidated equivalent of gravel.

Conservation cropping system. Growing crops in

combination with needed cultural and management

practices. If soil-improving crops and practices used in

the system more than offset the soil-
depleting crops and practices, then it is a good

conservation cropping system. Cropping systems are

needed on all tilled soils. Examples of soil-improving

practices in a conservation cropping system are crop

rotations that include grasses and legumes and the

return of crop residue to the soil. Other practices

include green manure crops of grasses and legumes,

proper tillage, adequate fertilization, and weed and

pest control.

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 are:

Loose.-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.-Readily deformed by moderate pressure but

can be pressed into a lump; will form a "wire" when

rolled between thumb and forefinger.

Sticky.-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.

Coprogenous earth (sedimentary peat). Fecal material

deposited in water by aquatic organisms.

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.

Crop residue management. Returning crop residue to the

soil, which helps to maintain soil structure, organic

matter content, and fertility and helps to control

erosion.

Cropping system. Growing crops using a planned

system of rotation and management practices.

Cross-slope farming. Deliberately conducting farming

operations on sloping farmland in such a way that

tillage is across the general slope of the land.

Crown. The upper part of a tree or shrub, including the

living branches and their foliage.

Culmination of mean annual increment (CMAI). The

average yearly volume growth of a stand of trees from

the year of origin to that age which gives the highest

average. The CMAI for a particular species is based on

the applicable yield table publication and is calculated

according to those volumes given for the smallest size.

Cutbanks cave (in tables). The walls of excavations

tend to cave in or slough.

Delta. A body of alluvium that has a nearly flat and fan

shaped surface, deposited at or near the mouth of a

river or stream where it enters a body of relatively

quiet water, generally a sea or lake.

Depth to rock (in tables). Bedrock is too near the

surface for the specified use.

Dip slope. A slope of the land surface, roughly determined

by and approximately conforming with the dip of

underlying bedded rock.

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.-These soils have very high and

high hydraulic conductivity and low water-holding

capacity. They are not suited for crop production

unless irrigated.

Somewhat excessively drained. -These soils have

high hydraulic conductivity and low water-holding

capacity. Without irrigation, only a narrow range of

crops can be grown and yields are low.

Well drained.-These soils have intermediate waterholding capacity. They retain optimum amounts of

moisture, but they are not wet close enough to the

surface or long enough during the growing season for

yields to be reduced.

Moderately well drained.-These soils are wet close

enough to the surface or long enough for planting or

harvesting to be delayed or yields of some field crops

to be reduced unless an artificial drainage system is

provided. Moderately well drained soils commonly

have a layer with low hydraulic conductivity, a wet

layer relatively high in the profile, additions of water by

seepage, or some combination of these.

Somewhat poorly drained.-These soils are wet

close enough to the surface or long enough for

planting or harvesting to be delayed or crop
growth to be markedly restricted unless an artificial

drainage system is provided. Somewhat poorly

drained soils commonly have a layer with low

hydraulic conductivity, a wet layer high in the profile,

additions of water through seepage, or a combination

of these.

Poorly drained.-These soils commonly are so wet at

or near the surface during a considerable part of the

year that field crops cannot be grown under natural

conditions. Poorly drained conditions are caused by a

saturated zone, a layer with low hydraulic

conductivity, seepage, or a combination of these.

Very poorly drained.-These soils are wet to the

surface most of the time. The wetness prevents the

growth of important crops (except for rice) unless

an artificial drainage system is provided.

Drainage, surface. Runoff, or surface flow of water,

from an area.

Duff. 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.

Eluviation. The movement of material in true solution or

colloidal suspension from one place to another within

the soil. Soil horizons that have lost material through

eluviation are eluvial; those that have received

material are illuvial.

Eolian soil material. Earthy parent material accumulated

through wind action; commonly refers to sandy

material in dunes or to loess in blankets on the

surface.

Ephemeral stream. A stream, or reach of a stream, that

flows only in direct response to precipitation. It

receives no long-continued supply from melting snow

or other source, and its channel is above the water

table at all times.

Erosion. The wearing away of the land surface by water,

wind, ice, or other geologic agents and by such

processes as gravitational creep.

Erosion (geologic). Erosion caused by geologic

processes acting over long geologic periods and

resulting in the wearing away of mountains and the

building up of such landscape features as flood

plains and coastal plains. Synonym: natural erosion.

Erosion (accelerated). Erosion much more rapid than

geologic erosion, mainly as a result of human or

animal activities or of a catastrophe in nature; for

example, fire that exposes the surface.

Erosion hazard rating. Soils in cultivated areas are rated

assuming the soil is bare. Soils in woodland

are rated for the most severe practice on the soils,

namely clearcut and burn.

Escarpment. A relatively continuous and steep slope or

cliff breaking the general continuity of more gently

sloping land surfaces and produced by erosion or

faulting. Synonym: scarp.

Esker (geology). A narrow, winding ridge of stratified

gravelly and sandy drift deposited by a stream

flowing in a tunnel beneath a glacier.

Excess fines (in tables). Excess silt and clay in the soil.

The soil is not a source of gravel or sand for

construction purposes.

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.

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; generally on the downhill

side of the road.

Fine textured soil. Sandy clay, silty clay, and clay.

Firebreaks. Spaces cleared of flammable material to stop

or check creeping of running fires. They also serve

as a line from which to facilitate the movement of

equipment in fire suppression. Most roads also serve

as firebreaks.

First bottom. The normal flood plain of a stream,

subject to frequent or occasional flooding.

Flaggy soil material. Material that is, by volume, 15 to 35

percent flagstones. Very flaggy soil material is 35 to

60 percent flagstones, and extremely flaggy soil

material is more than 60 percent flagstones.

Flagstone. A thin fragment of sandstone, limestone, slate,

shale, or (rarely) schist 6 to 15 inches (15 to 38

centimeters) long.

Flood plain. A nearly level alluvial plain that borders a

stream and is subject to flooding unless protected

artificially.

Fluvial. Of or pertaining to rivers; produced by river

action, as a fluvial plain.

Foothill. A steeply sloping upland that has relief of as

much as 1,000 feet (or 300 meters) and fringes a

mountain range or high-plateau escarpment.
Foot slope. The inclined surface at the base of a hill.

Forb. Any herbaceous plant not a grass or a sedge.

Forest cover. All trees and other woody plants

(underbrush) covering the ground in a forest.

Forest type. A stand of trees similar in composition and

development because of given physical and

biological factors by which it may be differentiated

from other stands.

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

meltwater.

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 meltwater. Many deposits are

interbedded or laminated.

Glaciomarine drift. Unsorted, nonstratified glacial drift

consisting of clay, silt, sand, and rock fragments

transported and deposited by floating icebergs in

sea water.

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.

Grassed waterway. A natural or constructed waterway,

typically broad and shallow, seeded to grass as

protection against erosion. Conducts surface water

away from cropland.

Gravel. Rounded or angular fragments of rock up to 3

inches (2 millimeters to 7.6 centimeters) in diameter.

An individual piece is a pebble.

Gravelly soil material. Material that is 15 to 50 percent, by

volume, rounded or angular rock fragments, not

prominently flattened, up to 3 inches (7.6 centimeters)

in diameter.

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.

Gully. A miniature valley with steep sides cut by running

water and through which water ordinarily runs only

after rainfall. The distinction between a gully and a

rill is one of depth. A gully generally is an obstacle

to farm machinery and is too deep to be obliterated

by ordinary tillage; a rill is of lesser depth and can

be smoothed over by ordinary tillage.

Hard rock. Rock that cannot be excavated except by

blasting or by the use of special equipment that is

not commonly used in construction.

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.

Head out. To form a flower head.

Hemic soil material (mucky peat). Organic soil material

intermediate in degree of decomposition between

the less decomposed fibric material and the more

decomposed sapric material.

High-residue crops. Crops such as small grain and corn

used for grain. If properly managed, residue from

these crops can be used to control erosion until the

next crop in the rotation is established. These crops

return large amounts of organic matter to the soil.

Hill. A natural elevation of the land surface, rising as

much as 1,000 feet above surrounding lowlands,

commonly of limited summit area and having a welldefined outline; hillsides generally have slopes of

more than 15 percent. The distinction between a hill

and a mountain is arbitrary and is dependent on

local usage.

Horizon, soil. A layer of soil, approximately parallel to the

surface, having distinct characteristics produced by

soil-forming processes. In the identification of soil

horizons, an uppercase letter represents the major

horizons. Numbers or lowercase letters that follow

represent subdivisions of the major horizons. An

explanation of the subdivisions is given in the Soil

Survey Manual. The major horizons are as follows:
O horizon.-An organic layer of fresh and

decaying plant residue.

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.

E horizon.- The mineral horizon in which the main

feature is loss of silicate clay, iron, aluminum, or some

combination of these.

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 overlying soil material. 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 number 2 precedes the letter C.

R layer.-Consolidated bedrock beneath the soil. The

bedrock commonly underlies a C horizon, but it 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.

Igneous rock. Rock formed by solidification from a molten

or partially molten state. Major varieties include

plutonic and volcanic rock. Examples are

andesite, basalt, and granite.

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.

Impervious soil. A soil through which water, air, or roots

penetrate slowly or not at all. No soil is absolutely

impervious to air and water all the time.

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 capacity. The maximum rate at which water

can infiltrate into a soil under a given set of

conditions.

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

Intermittent stream. A stream, or reach of a stream, that

flows for prolonged periods only when it receives

ground-water discharge or long, continued

contributions from melting snow or other surface and

shallow subsurface sources.

Irrigation. Application of water to soils to assist in

production of crops. Methods of irrigation are:

Border.-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 closegrowing 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.

Knoll. A small, low, rounded hill rising above adjacent

landforms.

Lacustrine deposit (geology). Material deposited in lake

water and exposed when the water level is

lowered or the elevation of the land is raised.

Landslide. The rapid downhill movement of a mass of

soil and loose rock, generally when wet or saturated.

The speed and distance of movement, as well as the

amount of soil and rock material, vary greatly.

Large stones (in tables). Rock fragments 3 inches (7.6

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.

Light textured soil. Sand and loamy sand.

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-residue crops. Crops such as corn used for silage and

peas, beans, and potatoes. Residue from these crops

is not adequate to control erosion until the next crop

in the rotation is established. These crops return little

organic matter to the soil.

Low strength. The soil is not strong enough to support

loads.

Mean annual increment. The average yearly volume

growth of a stand of trees from the year of origin to

the age under consideration.

Mechanical treatment. Use of mechanical equipment for

seeding, brush management, and other

management practices.

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.

Metasedimentary rock. Rock that is similar to

metamorphic rock but is only slightly altered.

Mineral soil. Soil that is mainly mineral material and low

in organic material. Its bulk density is more than

that of organic soil.

Minimum tillage. Only the tillage essential to crop

production and prevention of soil damage.

Miscellaneous area. An area that has little or no natural

soil and supports little or no vegetation.

Moderately coarse textured soil. Coarse sandy loam,

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,

size-fine, 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).

Mountain. A natural elevation of the land surface, rising

more than 1,000 feet above surrounding lowlands,

commonly of restricted summit area (relative to a

plateau) and generally having steep sides and

considerable bare-rock surface. A mountain can occur

as a single, isolated mass or in a group forming a

chain or range.

Muck. Dark colored, finely divided, well decomposed

organic soil material. (See Sapric soil material.)

Mudstone. Sedimentary rock formed by induration of silt

and clay in approximately equal amounts.

Munsell notation. A designation of color by degrees of

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.)

Nutrient, plant. Any element taken in by a plant essential to

its growth. Plant nutrients are mainly nitrogen,

phosphorus, potassium, calcium, magnesium, sulfur,

iron, manganese, copper, boron, and zinc obtained

from the soil and carbon, hydrogen, and oxygen

obtained from the air and water.

Observed rooting depth. Depth to which roots have

been observed to penetrate.

Open space. A relatively undeveloped green or wooded

area provided mainly within an urban area to

minimize feelings of congested living.

Organic matter. Plant and animal residue in the soil in

various stages of decomposition.

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.

Ped. An individual natural soil aggregate, such as a

granule, a prism, or a block.

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.

Percolation. The downward movement of water through 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 0.2 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

Phase, soil. A subdivision of a soil series based on

features that affect its use and management. For

example, slope, stoniness, and thickness.

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.

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.

Plateau. An extensive upland mass with a relatively flat

summit area that is considerably elevated (more than

100 meters) above adjacent lowlands and separated

from them on one or more sides by escarpments.

Plowpan. A compacted layer formed in the soil directly

below the plowed layer.

Ponding. Standing water on soils in closed

depressions. Unless the soils are artificially

drained, the water can be removed only by

percolation or evapotranspiration.

Poor filter (in tables). Because of rapid permeability, or an

impermeable layer near the surface, the soil may not

adequately filter effluent from a waste disposal

system.

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.

Potential native plant community. The plant community

on a given site that will be established if present

environmental conditions continue to prevail and the

site is properly managed. (See Climax plant

community.)

Potential rooting depth (effective rooting depth). Depth to

which roots could penetrate if the content of moisture

in the soil were adequate. The soil has no properties

restricting the penetration of roots to this depth.

Prescribed burning. The application of fire to land under

such conditions of weather, soil moisture, and time

of day as presumably will result in the intensity of

heat and spread required to accomplish specific

forest management, wildlife, grazing, or fire hazard

reduction purposes.

Productivity, soil. The capability of a soil for producing a

specified plant or sequence of plants under specific

management.

Profile, soil. A vertical section of the soil extending
through all its horizons and into the parent

material.

Ravel (dry ravel). Sloughing of weakly cohesive or

noncohesive soils, organic material, and rock on

steep slopes during dry periods due to gravity.

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 degrees of acidity or

alkalinity, expressed as pH values, are:

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

Reforestation. The establishment of planted or naturally

occurring tree seedlings in an area that was once

forested; also includes the physical acts associated

with planting tree seedlings in the ground. The

expected period needed for natural reforestation is

described by the terms readily, periodically, and

infrequently. Readily indicates that seedlings are

expected to occupy the area in 2 to 5 years;

periodically, in 5 to 10 years; and infrequently, in 10 to

20 years.

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.

Rill. A steep-sided channel resulting from accelerated

erosion. A rill generally is a few inches deep and not

wide enough to be an obstacle to farm machinery.

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 groundwater 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

sand-sized 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.

Saprolite (soil science). Unconsolidated residual

material underlying the soil and grading to hard

bedrock below.

Scarification. The act of abrading, scratching,

loosening, crushing, or modifying the surface to

increase water absorption or to provide a more

tillable soil.

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.

Sequum. A sequence consisting of an illuvial horizon and

the overlying eluvial horizon. (See Eluviation.)

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.

Sheet erosion. The removal of a fairly uniform layer of soil

material from the land surface by the action of rainfall

and surface runoff.

Shrink-swell (in tables). 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.

Silica. A combination of silicon and oxygen. The

mineral form is called quartz.
Silica-sesquioxide ratio. The ratio of the number of

molecules of silica to the number of molecules of

alumina and iron oxide. The more highly weathered

soils or their clay fractions in warm-temperate, humid

regions, and especially those in the tropics, generally

have a low ratio.

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.

Similar soils. Soils that share limits of diagnostic criteria,

behave and perform in a similar manner, and have

similar conservation needs or management

requirements for the major land uses in the survey

area.

Site class. A grouping of site indexes into five to seven

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

show the average heights of dominant trees for the

range of ages on soils that differ in productivity. Each

level is represented by a curve. The basis of the

curves is the height of dominant trees that are 50

years of age.

Site curve (100 year). A set of related curves on a graph

that show the average heights of dominant and

codominant trees for a range of ages on soils that

differ in productivity. Each level is represented by a

curve. The basis of the curves is the height of

dominant and codominant trees that are 100 years of

age.

Site index. A numerical index equal to the height that

dominant or dominant and codominant trees reach at a

specific age, usually 50 or 100 years. This index, the

age of the stand of trees, and the appropriate yield

table publication are used in determining yields.

Skid trails. The paths created by skidding logs and the

bulldozer or tractor used to pull them.

Skidding. A method of moving felled trees to a nearby,

central area for transport to a processing facility. Most

systems involve pulling the trees with wire cables

attached to a bulldozer or rubber-tired tractor.

Generally, one end is lifted when the felled trees are

skidded or pulled. As a result, friction and surface

disturbance are minimized.

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. In

this survey the following slope classes are

recognized:

Nearly level............................................0 to 3 percent

Gently sloping .......................................3 to 8 percent

Moderately sloping .............................8 to 15 percent

Moderately steep ..............................15 to 30 percent

Steep ................................................30 to 60 percent

Very steep ............................... 60 percent and higher

Slope (in tables). Slope is great enough that special

practices are required to ensure satisfactory

performance of the soil for a specific use.

Slope alluvium. Sediment gradually transported on

mountainsides or hillslopes primarily by alluvial

processes and characterized by particle sorting. In a

profile sequence, sediments may be distinguished by

differences in size or specific gravity of coarse

fragments and may by separated by stone lines.

Slow intake (in tables). The slow movement of water

into the soil.

Small stones (in tables). Rock fragments less than 3

inches (7.6 centimeters) in diameter. Small stones

adversely affect the specified use of the soil.

Smeary (weakly). Under moderately strong force between

thumb and forefinger, the soil material changes

suddenly to fluid, the fingers skid, and the soil

smears. This is one of the properties associated with

weathered volcanic ash.

Soft rock. Rock that can be excavated with trenching

machines, backhoes, small rippers, and other

equipment commonly used in construction.

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 millimeters in

equivalent diameter and ranging between specified

size limits. The names and sizes, in millimeters, of

separates recognized in the United States are as

follows:

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, E,

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.

Stand density. The degree to which an area is covered

with living trees. It is usually expressed in units of

basal area per acre, number of trees per acre, or the

percentage of ground covered by the tree canopy as

if viewed from above.

Stone line. A concentration of coarse fragments in a soil.

Generally, it is indicative of an old weathered surface.

In a cross section, the line may be one fragment or

more thick. It generally overlies material that

weathered in place and is overlain by recent

sediment of variable thickness.

Stones. Rock fragments 10 to 24 inches (25 to 60

centimeters) in diameter if rounded or 6 to 15

inches (15 to 38 centimeters) in length if flat.

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 grain (each grain by itself, as in dune sand) or

massive (the particles adhering without any regular

cleavage, as in many hardpans).

Stubble mulch. Stubble or other crop residue left on the soil

or partly worked into the soil. It protects the soil from

wind and water erosion after harvest, during

preparation of a seedbed for the next crop, and

during the early growing period of the new crop.

Subsoil. Technically, the B horizon; roughly, the part of the

solum below plow depth.

Subsoiling. Tilling a soil below normal plow depth,

ordinarily to shatter a hardpan or claypan.

Substratum. The part of the soil below the solum.

Subsurface layer. Technically, the E 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."

Tail water. The water just downstream of a structure.

Talus. Rock fragments of any size or shape, commonly

coarse and angular, derived from and lying at the

base of a cliff or very steep, rock slope. The

accumulated mass of such loose, broken rock

formed chiefly by falling, rolling, or sliding.

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.

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.

Trace elements. Chemical elements, for example, zinc,

cobalt, manganese, copper, and iron, that are in soils

in extremely small amounts. They are essential to

plant growth.

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 meltwater. In

nonglaciated regions, alluvium deposited by

heavily loaded streams.

Variegation. Refers to patterns of contrasting colors

assumed to be inherited from the parent material

rather than to be the result of poor drainage.

Varve. A sedimentary layer of a lamina or sequence of

laminae deposited in a body of still water within a

year. Specifically, a thin pair of graded

glaciolacustrine layers seasonally deposited, usually

by meltwater streams, in a glacial lake or other body

of still water in front of a glacier.

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 a sunflower) wilts so much that it

does not recover when placed in a humid, dark

chamber.

Windthrow hazard. The likelihood that trees will be blown

over by the wind and partially or completely uprooted.

The predicted severity of windthrow is

described by the terms occasionally and frequently.

Occasionally means that as much as 5 percent of the

trees in a stand may be blown down during periods of

excessive wetness and moderate or strong winds.

The hazard of windthrow is moderate. Frequently

means that more than 5 percent of the trees in a

stand may be blown down during periods of excessive

wetness and moderate or strong winds. The hazard of

windthrow is severe.

Yarding paths. The paths created by cable-yarded logs as

they are pulled up or down a hill to a nearby, central

area.

Yield (woodland). The volume of wood fiber from

harvested trees taken from an area of a certain size.

Usually measured in board feet or cubic feet per

acre.