A^f/^AVegetation and

Environmental Features of

Forest and Range

Ecosystems

FOREST SERVICE

U.S. DEPARTMENT OF AGRICULTURE AGRICULTURE HANDBOOK NO. 475
USDA, National Agnouttural Library

NALBldg

10301 Baltimore Blvd

^QitsviUe. MD 20705-2351

This is one of four reports that present the concepts, procedures, information, and

analyses developed in the Forest-Range Environmental Study (FRES), Forest Service,

U.S. Department of Agriculture, 1970^1972.

The basic document is:

• The Nation's Range Resources—A Forest-Range Environmental Study (Forest

Resource Report 19). This report presents basic concepts and methods, information on

supply of and demand for resources from all the Nation's forest-range environment,

and analyses of alternative mixtures of resource use.

Supporting The Nation's Range Resources—A Forest-Range Environmental Study are:

• Forest-Range Environmental Production Analytical System (FREPAS) (Agriculture Handbook 430), the analytical and computer capability developed for FRES.

• Vegetation and Environmental Features of Forest and Range Ecosystems (Agriculture Handbook 475), a system of classifying all the land area of the 48 contiguous

States into 34 units, called ecosystems, and a description of each.

• Range Management Practices: Investment Costs, 1970 (Agriculture Handbook

435). Definitions of the 18 range management practices used in the Forest-Range

Environmental Study (FRES) and lists of investment costs for each practice in

each of 956 resource units of forest-range found within 34 major ecosystems.

For copies write to the U.S. Department of Agriculture, Forest Service, Washington,

D.C. 20250.

/v^Ai^

yag*^^/^

The cover design symbolizes the interrelationship

of organisms and their environment and the sun

—the moving force without which life could not

exist. Plants and animals all work together within

an ecological system, an ecosystem.
VEGETATION AND

ENVIRONMENTAL FEATURES

OF FOREST AND RANGE ECOSYSTEMS

by

George A. Garrison, Ardell J. Bjugstad, Don A. Duncan,

Mont E. Lewis, and Dixie R. Smith

Forest Service July 1977

U.S. Department of Agriculture Agriculture Handbook No. 475

For sale by the Superintendent of Documents. U.S. Government Printing Office, Washington, D.C. 20402

Stock Number 001-000-03306-9
Contents

Page

Index to FRES Ecosystems and the Küchler System Equivalents iii

Forest and Woodland Ecosystems ._„_.„„„„ ____._.____._ iii

Shrubland Ecosystems iv

Grassland Ecosystems „_________ iv

Alpine Ecosystem ..„____„___„_ iv

Introduction _._._ __„______.______ _^_____ 1

Classification of Vegetation 1

Classification of Productivity and Condition ___„___._ 2

Source Materials 3

The Vegetation Map „_ 3

Descriptions of Ecosystems — ________________.________________„_ 3

Appendix A—General References _________,.__„________ 63

Appendix B—References on Mammals and Birds __ 63

Appendix C—References Used in Describing Individual Ecosystems „_.64

Garrison, George A., Ardell J. Bjugstad, Don A. Duncan,

Mont E. Lewis, and Dixie R. Smith.

1977. Vegetation and Environmental Features of Forest and Range Ecosystems.U.S. Dep. Agrie, Agrie. Handb. 475, 68 p., illus.

This publication describes the 34 ecosystems into which all the land of the

48 contiguous States has been classified in the Forest-Range Environmental

Study (FRES) of the Forest Service, U.S. Department of Agriculture. The

description of each ecosystem discusses physiography, climate, vegetation,

fauna, soils, and land use. For a number of the ecosystems, the descriptions

include discussions of the productivity classes into which these units have

been categorized. For each of these ecosystems, the herbage production in

each class is given. An index relates the ecosystems to phytocoenoses.

Keywords: Ecosystems, environment, forests, range, range productivity,

phytocoenoses.

Library of Congress Catalog Card Number: 74-600120
Index to FRES Ecosystems and the Kuchler System Equivalents

The number and name of each ecosystem is followed by the phytocoenosis designation or designations (e.g., K-1 Spruce-cedar-hemlock forest) assigned by A. W. Küchler on his 1966 map,

"Potential Natural Vegetation," (USDI Geol. Surv. 1967, 1970).^

FOREST AND WOODLAND ECOSYSTEMS

Page

10. White-red-jack pine 3

K-86 Great Lakes pine forest

11. Spruce-fir 5

K-84 Great Lakes spruce-fir forest

K~85 Conifer bog

K-87 Northeastern spruce-fir forest

K-88 Southeastern spruce-fir forest

12. Longleaf-slash pine 5

K-102 Southern mixed forest

(serai stages)

K-106 Subtropical pine forest

(southern Florida)

13. Loblolly-shortleaf pine 8

K-lOO Northeastern oak-pine forest

K-101 Oak-hickory-pine forest

K-104 Pocosin

K-105 Sand pine scrub

14. Oak-pine 9

K-101 Oak-hickory-pine forest

K-102 Southern mixed forest

15. Oak-hickory 10

K-72 Oak savanna

K-73 Mosaic of bluestem prairie

(K-66) and oak-hickory

forest (K-91)

K-75 Cross Timbers

K-80 Black Belt

K-91 Oak-hickory forest

K-95 Appalachian oak forest

16. Oak-gum-cypress 14

K-81 Live oak-sea oats

K-82 Cypress savanna

K-96 Mangrove

K-103 Southern'flood-plain forest

17. Elm-ash-cottonwood 15

K-89 Northern flood-plain forest

K-92 Elm-ash forest

18. Maple-beeeh-birch 16

K-90 Maple-basswood forest

K-93 Beech-maple forest

K-94 Mixed mesophytic forest

K-97 Northern hardwoods

K-98 Northern hardwoods-fir forest

K-99 Northern hardwoods-spruce

forest

Page

19. Aspen-birch 18

K-97 Northern hardwoods

(serai stages)

K-98 Northern hardwoods-fir forest

(serai stages)

K-99 Northern hardwoods-spruce

forest (serai stages)

20. Douglas-fir 18

K-2 Cedar-hemlock-Douglas-fir

forest

K-11 Douglas-fir forest

K-24 Mosaic of cedar-hemlockDouglas-fir forest (K-2)

and Oregon oakwoods (K-22)

K-25 California mixed evergreen

forest

21. Ponderosa pine 21

K-5 Mixed conifer forest

K-9 Pine-cypress forest

K-10 Western ponderosa forest

K-15 Eastern ponderosa forest

K-16 Black Hills pine forest

K-17 Pine-Douglas-fir forest

K-18 Arizona pine forest

22. Western white pine 24

K-12 Cedar-hemlock-pine forest

23. Fir-spruce 24

K-3 Silver fir-Douglas-fir forest

K-4 Fir-hemlock forest

K-7 Red fir forest

K-14 Western spruce-fir forest

K-19 Spruce-fir-Douglas-fir forest

K-20 Southwestern spruce-fir forest

24. Hemlock-Sitka spruce 27

K-1 Spruce-cedar-hemlock forest

25. Larch 27

K-13 Grand fir-Douglas-fir forest

26. Lodgepole pine^ 30

K-8 Lodgepole pine-subalpine

forest

27. Redwood _..., 31

K-6 Redwood forest

28. Western hardwoods 31

K-22 Oregon oakwoods

K-26 California oakwoods

1 Years and accompanying references in parentheses

refer to literature cited in Appendix A—General Refer2 Contains the USDA Forest Service's (1966) Forest

Survey local types 95-Bristlecone pine and 96-Whitebark

pine that are classified by the Forest Survey as noncommercial but generally occurring in ecosystems related to others included under this general designation.

Ill
SHRUBLAND ECOSYSTEMS

29.

30.

31.

32.

33.

34

35.

36.

Sagebrush .=...„.„...=„.......

K-32 Great Basin sagebrush

K»49 Sagebrush steppe

K-50 Wheatgrass-needlegrass

shrubsteppe

Desert shrub .....„..„,

K-28 Mesquite bosques

K-33 Blackbrush

K-34 Saltbush-greasewood

K-35 Creosotebush

K-36 Creosotebush-bursage

K-37 Paloverde-cactus shrub

Page

33

35

37

39

Shinnery .=..

K-64 Shinnery

Texas savanna

K~38 Ceniza shrub

K-54 Mesquite-acacia savanna

K-55 Mesquite-live oak savanna

K-77 Juniper-oak savanna

K--78 Mesquite-oak savanna

Southwestern shrubsteppe 41

K-52 Grama-tobosa shrubsteppe

K-53 Trans-Peeos shrub savanna

Chaparral-mountain shrub .................. 43

K-27 Oak-juniper woodland

Transition between oakjuniper woodland (K-27)

and mountain-mahoganyoak scrub (K-31)

Chaparral

Coastal sagebrush

Mountain-mahogany-oak scrub

Pinyon-juniper 45

K-21 Juniper-pinyon woodland

K^28

K-29

K-30

K-31

GRASSLAND ECOSYSTEMS

Mountain grasslands

K-40 Fescue-oatgrass

K=-43 Fescue-wheatgrass

K-44 Wheatgrass-bluegrass

47

37.

38.

K-46 Fescue-mountain muhly

prairie

K-56 Foothills prairie

Mountain meadows ^

39.

40.

41.

42.

Page

49

Plains grasslands 50

K-67 Grama-needlegrass-wheatgrass

Grama-buffalo grass

Wheatgrass-needlegrass

Wheatgrass-bluestemneedlegrass

Wheatgrass-grama-buffalo

grass

Bluestem-grama prairie

Mesquite-buffalo grass

Prairie 52

K-63 Sandsage-bluestem prairie

Bluestem prairie

Nebraska Sand Hills prairie

Blackland prairie

Bluestem-sacahuiste prairie

Cedar glades

Fayette prairie

Desert grasslands 54

K-47 Grama-galleta steppe

K-48 Grama-tobosa prairie

K-51 Galleta-three-awn shrubsteppe

Wet grasslands 56

K-42 Tule marshes

Northern cordgrass prairie

Southern cordgrass prairie

Palmetto prairie

Everglades

Annual grasslands 58

K-41 California steppe

K-58

K^59

K-60

K»61

K-62

K-76

K-66

K-67

K-68

K=^69

K-74

K-79

K-65

K-70

K-71

K-83

ALPINE ECOSYSTEM

44. Alpine ......,.......„.= 61

K-45 Alpine meadows and barren

3 Not recognized by Küchler but included in FRES

because of the significance of their management to

rangeland management.

IV
VEGETATION AND

ENVIRONMENTAL FEATURES

OF FOREST AND RANGE ECOSYSTEMS'

Introduction

This is one of the reports developed as part

of the Forest-Range Environmental Study

(FRES) of the Forest Service, U.S. Department of Agriculture. This report presents descriptive sketches of 34 soil-vegetation units,

called ecosystems. These cover all the land area

of the 48 contiguous States.

The descriptions of the ecosystems are condensations of a considerable body of literature,

data, and personal knowledge of the authors

and some of their colleagues. Each description

contains brief sections on physiography, climate, vegetation, fauna, soils, and land use. In

many instances the description also includes an

approximation of herbage and browse production, which may be general or detailed, depending upon the amount of information available.

Each ecosystem is numbered and titled. The

numbering arbitrarily begins with 10. Ecosystem 43 is not described in this publication

because, like certain other ecosystems, it does

not occur in tlie 48 contiguous States.

Subunits of the ecosystems described in this

report served as the land units for which 1970

yields of 22 products of forest and range lands

were estimated. These subunits, called resource

classes, also were used as the land bases for

predicting outputs from resources when six

different management strategies were applied

in turn within each resource class.

CLASSIFICATION OF VEGETATION

In establishing the system of classifying

vegetation, A. W. Küchler's (1964)2 scheme of

1 By George A. Garrison, principal plant ecologist,

Pacific Northwest Forest and Range Experiment Station; Ardell J. Bjugstad, principal plant ecologist, Rocky

Mountain Forest and Range Experiment Station; Don A.

Duncan, principal plant ecologist. Pacific Southwest

Forest and Range Experiment Station; Mont E. Lewis

(retired), formerly range conservationist, Intermountain Region; and Dixie R. Smith, chief ecologist, Washington Office—all of the USDA Forest Service.

2 Years and accompanying references in parentheses

refer to literature cited in Appendix A—General References.

mapping vegetation and his revised map of

1966, *Totential Natural Vegetation'' (USDI

GeoL Surv. 1967, 1970) were used as a basis

for aggregating many plant communities (phytocoenoses) into ecosystems. Küchler's system

is an approximation of the potential natural

vegetation of the United States, To simplify

data compilations, the forest and v^oodland

ecosystems were made synonymous with broad

geographic forest types described by the USDA

Forest Service (1967) in the standards for its

nationwide Forest Survey.

Many of the **real vegetation types'' of today

may continue to be managed so that they may

never develop to the Küchler potential. Nevertheless, the concept of potential vegetation provides a realistic common denominator for classification. It is quite widely accepted. Therefore,

equivalents were established where possible

between the commonly used vegetation units of

other land inventory systems and the communities established by Küchler. In this way, data

from the Bureau of Land Management, Bureau

of Indian Affairs, Soil Conservation Service,

National Park Service, Fish and Wildlife Service, and Forest Service were incorporated into

an inventory of land by ecosystems.

An ecosystem, as the term is used in the

study, may contain one or more major plant

communities. In all cases, closely related communities are aggregated into a specific ecosystem. For example, all of the many grassland

communities are aggregated into eight grassland ecosystems. On the other hand, the pinyonjuniper community is maintained by itself as

an ecosystem in this study. Areas of barren

desert and barren rock are included with the

ecosystems in which they occur. Lack of complete data in some cases and a practical need

for coordination of classification systems resulted in some compromises which meet the

practical objectives of the study.

In brief, the vegetation classification scheme

used in this report is a composite and compromise of some concepts yet is useful to the

objectives of the total study.
CLASSIFICATION OF

PRODUCTIVITY AND CONDITION

Forest Ecosystems

Classification of productivity and condition in

FRES differs for forest and for nonforest

ecosystems. For nonforest ecosystems, traditional concepts and data are available for use

in evaluating" productivity and condition in

relation to range management. To mechanically

extrapolate the concepts derived for Forest Service range to all categories of ownership is

comparatively easy. For forest ecosystems, the

productivity and condition classifications had

to be changed. Because the Forest Survey provides the best data on forest ecosystems, its

procedures for evaluating productivity and condition were adapted to meet the needs of FRES.

Fortunately, the Forest Survey (USDA Forest

SerV. 1973) was able to classify the Nation's

forest ecosystems in terms of ownership^ site

productivity class, and stand condition.

Forest productivity classes.-—The range productivity of forest ecosystems should be evaluated by some system that integrates all of the

outputs, but we cannot yet achieve such a

holistic ideal. We are compelled to accept the

Forest Survey system for estimating productivity based on capacity to produce wood. The

corresponding categories for estimating the

productivity of an acre of forest ecosystem are

as follows :

Forest Survey

site class

120 or more cubic feet

85 thru 119 cubic feet

50 thru 84 cubic feet

0 thru 49 cubic feet

FRES

productivity class

1. High

2. Moderately high

3. Moderately low

4. Low

Commercial forest types that produce less than

20 cubic feet are classified by the Forest Survey

as noncommercial unproductive. FRES considers forest lands in this category as being of

low productivity.

The productivity of forest ecosystems can be

described quite precisely in terms of volume of

wood produced, but the physical and biological

factors related to productivity can only be

described in generalities. It is impossible to

describe for forest ecosystems the myriad factors that affect productivity directly or indirectly. Forest ecologists now lean toward describing the potential production of sites in

terms of moisture relations. Generally, mesophytic sites have the highest productivity, and productivity falls off when too much or too little

moisture is available. Most of the characteristics associated with forest site productivity are

related to this concept of moisture availability.

Characteristics of sites of high productivity

and low productivity are as follows:

High Lota

Characteristic productivity productivity

Soil:

depth Deep Shallow

texture Friable or light Sandy or heavy

permeability ^ Permeable Impermeable

fertility Fertile Infertile

moisture Optimum Very dry or wet

drainage Well drained Boggy or swampy

Slope :

position Bottom lands Ridgetops and

and lower upper slopes

slopes

aspect North and South and

east facing west facing

Growing Long Short

season

Lesser Luxuriant Sparse

vegetation

Experts who are knowledgeable about the management and ecology of a specific forest ecosystem can point to the environmental factors

most closely related to production of timber,

herbs and shrubs, and other outputs of that

ecosystem.

Forest condition classes,—Three condition

classes unrelated to those used in evaluating

range productivity are recognized for each

forest ecosystem. Nonstocked stands are considered as being in coridíííotí 1. Seedling-sapling

and pole stands are considered as ^eing in

condition 2, Sawtimber stands are considered

as being in condition 3, This system is arbitrary,

for it overlooks stocking level, but the Forest

Survey cannot as yet provide any better single

system for evaluating condition.

Condition 1 is found on areas that are not

stocked with trees. Nonstocked areas, according to the Forest Survey, have less than 10

percent of the area occupied by growing stock

of forest trees. The nonstocked condition may

be temporary, as in the hiatus between crops

of forest trees, or it may be relatively permanent, as on lands covered with brush as a

result of forest fires. The Forest Survey classified nonstocked land according to its estimated

productivity for timber but did not classify

such land by timber type. Data on acreages of

nonstocked forest land in a State are given

only by ownership and productivity class.

Therefore, FRES prorated the nonstocked areas

to the forest ecosystems occurring in each kind

of ownership in a State.

Outputs from nonstocked forest ecosystems

are characterized in general by abundant herbage and browse production, rather high storm

runoff, and great diversity of species of wildlife. Wood production on sites of low productivity probably would only average 5 percent

of the yields of stands in good condition. However, on sites of fairly high to high productivity,

wood yields might average 25 to 40 percent of

the yields of stands in good condition.
In general it would cost comparatively little

to put nonstocked forest ecosystems under a

range management strategy that would achieve

maximum range outputs. This is in contrast to

the relatively great cost of restoring their timber production potentials.

Condition 2 stands with seedlings and saplings or poles have trees up to about 9 inches

in diameter generally, or up to 11 inches in the

Far West.

Condition 3 stands with sawlogs have at least

50 percent of the trees above 9 or 11 inches in

diameter.

Nonfcrest Ecosystems

Statements of vegetation yields given in the

ecosystem descriptions are approximations in

some cases, either because there were no production data for some of the vegetation units

or because the aggregating of several related

units under one ecosystem forced some compromises. Another type of problem exists in

conversion of production in pounds per acre to

grazing capacity, because herbage production

per se does not take into account the differences

between ecosystems in the quality or nutritive

value of their potential output. It is possible,

for example, for forage to be very low in nutritive value even though the volume or weight

of production is high. Thus, computing animal

unit-months of grazing capacity for some of

the ecosystems from the herbage weight data

presented would require application of appropriate discount factors for proper use level and

nutritive status; these factors are not included

in this report.

Nonforest classes,—For range ecosystems,

productivity classes are expressed in terms of

traditional concepts of herbage production.

Some ecosystems are potentially high producers

of herbage, and others are intermediate or low

producers. Accordingly, the productivity classification is relative to the production capability

of each range ecosystem, as follows.:

Potential

herbage

Class production

1 First quartile

2 Second quartile

Potential

herbage

Class production

3 Third quartile

4 Fourth quartile

The range condition classes are Good, Fair,

and Poor. They are based on vegetative cover,

the composition and vigor of the vegetation, and

soil factors.

SOURCE MATERIALS

General references consulted in preparing

the descriptions of the ecosystems are listed

in appendix A. References on mammals and

birds are given in appendix B. Other references

used in preparing the descriptions of the ecosystems are given in appendix C, by individual

ecosystems. The nomenclature of plants largely

follows ^'Standardized Plant Names,'' by H. P.

Kelsey and W. A. Dayton (1942).

THE VEGETATION MAP

The ecosystems map in the back of this report

is principally a combination of Küchler's map,

which was cited earlier, and the USDA Forest

Service map (USDI Geol. Surv. 1969, 1970),

developed in the Forest Survey of timber types.

Where the two mapping systems differed as to

forest type boundaries the Forest Service definition and delineation prevailed. The Forest

Service timber type map is based on a compilation of aerial photographs and production

inventories in the field. Preparation of the

ecosystems map used in this study was done

largely under the guidance of Dr. Bjugstad,

with assistance in the final stages from Jack

E. Schmautz, ecologist, Forest Service.

Descriptions of Ecosystems

NO. 10.—THE WHITE-RED-JACK PINE ECOSYSTEM

Physiography,—The white-red-jack pine

ecosystem occurs generally on smooth to irregular plains and tablelands of northern Lake

States and parts of New York and New England.

More than 50 percent of the area is gently

sloping.

Climate,—Precipitation averages 25-45 inches annually and is distributed rather evenly

throughout the year. Normal pan evaporation

is 30-35 inches. During the frost-free season

of 120-140 days, precipitation is roughly equal

to evaporation.

Vegetation.—-Forests in which 50 percent or

more of the stand is eastern white pine, red

pine, or jack pine, singly or in combination,

represent the white-red-jack pine ecosystem.

Common associates include oak, eastern hemlock, aspen, birch, northern white-cedar, and

maple. Much of this ecosystem is included in

Küchler's (USDI Geol. Surv. 1967, 1970)

Great Lakes pine forest community.

Fauna.—The white-tailed deer and black

bear are the most common larger mammals in

this ecosystem, and the moose inhabits the extreme northern portion. The woodland caribou

formerly was abundant. In times past the eastern timber wolf was very numerous and fed

on small animals and the larger mammals just

mentioned, but it has become very scarce and

is classified as an endangered species. The
Figure 1.—^Woodland of eastern white pine in the white-red-jack pine ecosystem.

F-312B94
coyote, bobcat, great horned owl, and hawks

are among current predators. The snowshoe

rabbit and other small forest mammals are the

main food source of the predators already

mentioned. Spruce grouse and ruffed grouse

inhabit the ecosystem. Porcupines inhabit parts

of the ecosystem and become a problem in forest

management when they are overly abundant.

Breeding bird populations average about 153

pairs per 100 acres. The blackburnian and the

black-throated green warbler are the most

abundant. Other birds include the whippoorwill,

crested flycatcher, wood pewee, white-breasted

nuthatch, veery, tanagers, ruffed grouse,

great horned owl, pileated woodpecker, hairy

woodpecker, downy woodpecker, blue jay,

chickadees, red-eyed vireo, black-and-white

warbler, ovenbird, redstart, black-throated

blue warbler, hermit thrush, magnolia warbler,

Canada warbler, yellow-bellied sapsucker, olivesided flycatcher, red-breasted nuthatch, brown

creeper, winter wren, blue-headed vireo, myrtle

warbler, slate-colored junco, and white-throated

sparrow. The endangered Kirtland's warbler

occurs in limited areas.

Soils,—The cool, moist soils are predominantly Spodosols. They have a low supply of bases

and a horizon in which organic matter and compounds of iron and aluminum have accumulated,

but they have no dense, brittle, or indurated

horizon (Haplorthods). Soils of a significant

proportion of the ecosystem are moist throughout the year and coarse textured, and they lack

pedogenic horizons (Udipsamments).

Land use,—Nearly all of the land is forested

and is used principally for lumbering and recreation. The associated cropland is devoted

largely to growing potatoes and forage for

dairy cattle. Large urban areas characterize the

northeastern portions.

NO. 11.—THE SPRUCE-FIR ECOSYSTEM

Physiography,—The spruce-fir ecosystem

occurs on flat plains and tableland in the Lake

and New England States and at high elevations

in the Appalachian Mountains. At high elevations it occurs as far south as West Virginia.

Except for some especially high places, local

relief is almost entirely less than 500 feet and

often less than 100 feet. Well over half of the

area is gently sloping.

Climate»—Normal annual precipitation is

30-40 inches, half of which falls during the

frost-free season of 120-140 days. Normal annual evaporation is 30-40 inches. Evaporation

is about equal to precipitation during the frostfree season.

Vegetation,—Forestñ in which 50 percent or

more of the stand is spruce or true fir, singly

or in combination, characterize this ecosystem.

Common associates include northern whitecedar, tamarack, maple, birch, eastern hemlock, and eastern white pine.

Fauna,—The fauna of the spruce-fir ecosystem is similar to that described for other

northern conifer regions. A list of mammals

at Mount Katahdin, Maine, includes moose,

woodland caribou, lynx, marten, black bear,

long-tailed weasel, white-footed mouse, and

other mice and shrews. The moose, black bear,

and white-tailed deer are the most common

larger animals in the conifer areas.

The ruffed grouse is common throughout this

ecosystem. The wild turkey may be found

toward the south; the spruce grouse is found

more to the north. The eastern timber wolf is

considered an endangered species. Characteristic breeding birds of the ecosystem in the

Northeastern States are the olive-backed

thrush, magnolia warbler. Cape May warbler,

myrtle warbler, bay-breasted warbler, and

white-throated sparrow. The density of territorial males may be as high as 430 per 100

acres.

Soils,—The cool, moist soils of this ecosystem

are predominantly Spodosols, although a large

acreage of Histosols occurs in the Lake States.

The Spodosols have a low supply of bases and

a horizon in which organic matter and iron and

aluminum compounds have accumulated. No

dense, brittle, or indurated horizon is present

(Haplorthods). The Histosols are wet, organic

(peat and muck) soils.

Land use,—In the Northeastern States much

of the area is forested. Lumbering and recreation are major uses of the forest. About 10 percent of the area is in crops or pastures. Most

of the cropland is in forage crops for dairy

cattle. In many cases farming is a part-time

enterprise. Many farm occupants in this ecosystem earn their living from nonfarm occupations.

NO. 12.—THE LONGLEAF-SLASH PINE ECOSYSTEM

Physiography,—The longleaf-slash pine ecosystem is restricted to flat and irregular southern Gulf Coastal Plains. Well over 50 percent

of the area is gently sloping. Local relief is less

than 300 feet. The southern Gulf Coastal Plains

are a grouping of various plains of materials

ranging from sandy or gravelly to moderately

fine textured; these materials developed from
Figure 2.—A stand of black spruce in the Lake States portion of the spruce-fir ecosystem.

F-290077
F-602248

Figure 3.—Range of wiregrass, slash pine, and saw-palmetto in the longleaf-slash pine ecosystem, on the southern

Gulf Coastal Plains.

the underlying materials of unconsolidated

sands, silts, and clays. This ecosystem is often

referred to as the "southern pine hills," the

"piney-woods," or "pine-wiregrass type."

Climate.—The longleaf-slash pine ecosystem

occurs in a moist, warm climate where the average annual precipitation is 40-60 inches. The

average annual evaporation is 42-48 inches. The

average precipitation in the east is lowest in

autumn and highest in midsummer and in the

west is lowest in winter and spring. Summer

droughts are common in spite of the high

amount of precipitation and relatively low evaporation. The mean annual temperature is 64°

F, and the average frost-free period is 200-280

days, increasing from north to south.

Vegetation.—Forests in which 50 percent or

more of the stand is longleaf pine or slash pine,

singly or in combination, characterize this

ecosystem. Common associates include other

southern pines, oak, and sweet gum.

On most sites, grasses either dominate the

understory or share dominance with shrubby

vegetation. East of the Apalachicola River, wiregrasses are the main herbaceous plants ; in the

western section bluestems provide most of the

herbage. Other important grasses include panicums, paspalums, and dropseeds. Gallberry, sawpalmetto, waxmyrtle, and shining sumac are

prominent among the shrubs.

Fauna.—Longleaf-slash pine forests provide

habitats for a wide variety of animal life. Except for a few isolated areas where the black

bear or the endangered Florida panther may be

encountered rarely, the white-tailed deer is the

only large, indigenous mammal. Common small

mammals include the raccoon, the opossum, tree

squirrels, rabbits, and numerous species of

ground-dwelling rodents. The bobwhite and the

wild turkey are the principal gallinaceous game

birds. Resident and migratory nongame bird

species are numerous, as are species of migratory waterfowl. The red-cockaded woodpecker

is an endangered species. There are reptiles of

many species, the endangered American alligator being the largest of the reptiles.
Soils,—Longleaf-slash pine vegetation grows

on a wide variety of upland soils, but most of

the soils are acid in reaction, low in content of

organic mattery and deficient in the major plant

nutrients. The soils are derived mainly from

Coastal Plain sediments^ ranging from heavy

clay to gravjel, but with sandy materials predominating. Silty soils occur mainly on expansive level areas. Although sands are most prevalent in hilly sections, they occur on broad

flats in central Florida. Sandy soils having a

dense, though not impermeable, subsoil are

apparently most favorable for longleaf pine.

The soils are mainly of three orders: (1)

those low in content of bases and having subsurface horizons of accumulated clay—they are

usually moist, but during the warm season some

are dry part of the time (Ultisols) ; (2) those

with a low supply of bases and having in subsurface horizons an accumulation of amorphous

materials consisting of organic matter and

compounds of aluminum and, usually, iron—

these soils formed in acid, mainly coarsetextured materials (Spodosols) ; and (3) those

having no pedogenic horizons (Entisols). Hapludults, Haplaquods, and Quartzipsamments

comprise the principal great soil groups.

Land tese.—Portions of the ecosystem are

largely in farms; other portions are largely

owned by pulp and paper mills. In general, half

to nearly all of the ecosystem is forested, and

the trend is to more forest and improved pasture and less cropland. In southern Florida

only about one-fourth of the ecosystem is in

forest, which is grazed/ and about one-half is

in improved pasture.

ProduGtivity

Herbage and browse production varies from

0 to 4,000 pounds per acre, depending upon site

potential and the amount of the overstory of

pine and hardwoods. Even greater herbage

yields may be attained by conversion of land to

pasture, accompanied by fertilization and other

agricultural practices. Although it is possible to

get high yields, the herbage needs to be supplemented by protein, energy, and mineral feeds

during the winter. Appreciable forage yields

can be sustained by periodically burning the

range. In addition to removing the litter, burning improves forage quality and palatability.

NO. 13 .—THE LOBLOLLY-SHORTLEAF PINE ECOSYSTEM

Physiography.—The loblolly-shortleaf pine

ecosystem generally occurs on irregular Gulf

Coastal Plains and the Piedmont where 50-80

percent of the area is gently sloping. Local

relief is 100-600 feet on the Gulf Coastal Plains

and 300-1,000 feet on the Piedmont. About 20

percent of the ecosystem occurs on the flat

Coastal Plains where more than 80 percent of

the area is gently sloping and local relief is less

than 100 feet. This is the largest ecosystem in

the South and Southeast.

Climate.—T^e climate is rather uniform

throughout this ecosystem. Precipitation averages 40-60 inches annually. It is rather evenly

distributed through the year but peaks slightly

in midsummer or early spring in the western

areas. Precipitation exceeds evaporation, but

summer droughts occur. The average annual

temperature is 60°-68° F. The frost-free period

averages 200-280 days—250 days in the Piedmont.

Vegetation.—-This ecosystem is characterized

by forests in which 50 percent or more of the

stand is loblolly pine, shortleaf pine, or other

southern yellow pines, singly or in combination.

Common associates include oak, hickory, sweetgum, blackgum, red maple, and winged elm.

The main grasses are bluestems, panicums, and

longleaf unióla. Dogwood, viburnum, haw, blueberry, American beautyberry, yaupon, and

numerous woody vines are common.

Fauna.—-The fauna varies with the age and

stocking of the timber stand, the percentage of

deciduous trees, and the proximity to openings,

bottom-land forest types, etc. The white-tailed

deer is widespread, as is the cottontail. When

deciduous trees are present, the fox squirrel is

common on uplands. Gray squirrels are found

along intefseeting drainages. Raccoon and fox

are found throughout the ecosystem and are

hunted in many areas.

The eastern wild turkey, bobwhite, and

mourning dove are widespread. In mature forests the density of breeding birds is about 240

pairs per 100 acres. Of the 20 odd species present, the most common include the pine warbler,

cardinal, summer tanager, Carolina wren, rubythroated hummingbird, blue jay, hooded warbler, eastern towhee, and tufted titmouse. The

red-cockaded woodpecker is an endangered

species.

So¿Í5.—Typical soils are low in content of

bases and have subsurface horizons of accumulated clay. The clay horizons may be relatively

thin (Hapludults) or thick (Paleudults). They

are usually moist, but during the warmest

months some; are dry part of the time. Near the

coast the soils are seasonally wet and have

mottles or concentrations of iron and manganese or are gray (Aquults). The Gulf Coastal

Plains are underlain by unconsolidated sands,

silts, and clays, while the Piedmont is a dis-
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Figure 4.—A stand of shortleaf pine in the lobloUy-shortleaf pine ecosystem on the Gulf Coastal Plains.

sected plateau underlain by\ schists, gneisses, and woodland and less for crops

granites, sandstones, and shales.

Land use.—About 60-70 percent of the ecosystem is in forest, mostly in farm woodland,

but a few large areas are in National Forests

or are managed by large lumber companies.

About 20 percent of the area is in cropland, and

cash crops are produced. The trend recently has

been toward using more of the area for pasture

Productivity

Forage productivity is similar to that of the

longleaf-slash pine ecosystem. Forage produced

in this ecosystem is also nutritionally deficient

and must be supplemented during the winter

months to maintain the vigor of livestock.

NO. 14.—THE OAK-PINE ECOSYSTEM

Physiography.—The oak-pine ecosystem occurs on diverse land forms from the southernmost ridges and valleys of the Appalachians

westward across the Coastal Plains and north

into the Ozark Plateaus and Ouachita provinces.

Typically it occupies irregular plateaus where

50-80 percent of the area is gently sloping and

local relief is 100-300 feet. Almost as commonly

it occupies hills and mountains where gentle

slopes may cover as little as 20 percent of the

area and local relief may reach 1,000-3,000

feet.

Climate.—The climate is quite uniform

throughout the oak-pine ecosystem. Precipitation is relatively high, averaging 40-54 inches

annually, and most of it comes in late autumn

and spring. Summers are dry. The average

annual temperature varies from 55° to 68° F,

and the average freeze-free period is 180-220

days.

Vegetation.—This ecosystem is characterized

by forests in which 50 percent or more of the

stand is hardwoods, usually upland oaks, but

in which southern pines, mainly shortleaf pine.

9
Figure 5.—A stand of oak and pine in the oak-pine ecosystem.

F-477181

make up 25-49 percent of the stand. Common

associates include sweetgum, hickory, and

yellow-poplar. The productivity of the understory is relatively low, ranging from 50 to 500

pounds of herbage per acre per year.

Fauna.—The fauna is similar to that of the

adjacent oak-hickory ecosystem. Animals include the white-tailed deer, fox squirrel, and cottontail, and birds include the mourning dove,

bobwhite, and turkey. Many small mammals are

present, and the avian fauna is quite varied.

Soils.—Typical soils are low in supply of

bases and have a subsurface horizon of accumulated clay that ranges from relatively thin

(Hapludents) to thick (Paleudults). They are

usually moist but may become dry during part

of the dry season. The soils of the Ozarks are

developed from cherty limestone, while those of

the southern Appalachians are developed from

noncherty limestone.

Land use.—Most of this ecosystem is in

farms. About 60 percent is in forest, mostly in

small holdings. Twenty percent is cropland.

This is a cash-crop area. Less than 10 percent

is in pasture. Much of the livestock produced

is consumed on the home farm.

NO. 15.—THE OAK-HICKORY ECOSYSTEM

Physiography.—The oak-hickory ecosystem

occurs in areas of the eastern United States

that are more mesophytic than surrounding

areas. It reaches from southern Maine to Lake

Huron and to southern Texas. Its most continuous area is that known as the Ozark Plateaus

with extensions (Cross Timbers) into the semiarid grasslands of the southern Great Plains

10
and the interior low plateaus which fuse with

the glacial till plains south of the Great Lakes

and extend westward around the Ozark Plateaus

(immediately west of the central Appalachian

Highlands). This ecosystem also occurs on the

uppermost limits of the Appalachian Highlands,

known as the Blue Ridge and the Valley and

Ridge provinces of these highlands. These areas

are geologically the oldest uplifts in the United

States.

The Ozark Plateaus and their extensions

comprise an area of 72,000 square miles west

of the Mississippi River and south of the Missouri River. They consist of plateaus, variously

dissected, and of strong rock. Much of the area

is steep and lies at altitudes of 1,000 to 2,000

feet. Narrow belts of physiographically similar

areas extend as far south as Texas and New

Orleans and, along streams, north into Iowa.

The interior low plateaus and their extensions

lie east and north and extend westward around

the Ozark Plateaus. These plateaus are similar

to the Appalachian provinces in that the rocks

and soils are highly weathered. The extensions

are more characteristically glacial till plains.

The Blue Ridge and the Valley and Ridge

provinces are Appalachian Mountain belts west

of the Piedmont, The mountains are remnants

of a former highland. Most of the rocks are

old, strong, and of highly complex structure.

These provinces are characterized by "folded"

mountains in which resistant strata form ridges

and weaker rocks are worn down to lowlands.

The oak-hickory ecosystem also includes the

Black Belt, which is the richest and best known

lowland on the East Gulf Coastal Plain. It is so

named because of the deep, black residual soil.

The belt varies from 20 to 25 miles wide from

near the Georgia border, west through Alabama

and north through Mississippi. Its altitude

varies from 200 to 400 feet. Rivers cut through

the belt; there are few smaller streams.

Climate,—Temperatures vary considerably in

this ecosystem. The frost-free season is about

120 days in the northern portion and almost

300 days in southern Texas. In most of the area,

the frost-free season ranges from 160 to 200

days. Annual precipitation ranges from less

than 30 to more than 50 inches, averaging 35-

45 inches. More than half of the precipitation

falls in the warmest months. In many areas

potential evaporation during the warmest

months is about equal to the precipitation.

Vegetation.—The oak-hickory ecosystem varies from open to closed woods with a strong to

weak understory of shrubs, vines, and herbaceous plants. By definition, oak and hickory

must make up 50 percent of the stand, singly

or in combination. The ecosystem includes six

vegetation communities: the Black Belt on the

Coastal Plain in Alabama and Mississippi, the

oak-hickory forest and the mosaic of the oakhickory forest and bluestem prairie communities

of the Ozark Plateaus and interior low plateaus

and their extensions, the oak forest of the

Appalachians, the oak savanna, and Cross

Timbers.

Sweetgum and redcedar are close associates

in the southern (Black Belt) region of the ecosystem. Maple, elm, yellow-poplar, and black

walnut often are close associates in eastern

and northern parts of the oak forest and the

oak-hickory-bluestem mosaic. The major shrubs

are blueberry, viburnum, dogwood, rhododendron, and sumac. The major vines are woodbine, grape, poisonivy, greenbrier, and blackberry. Important herbaceous plants are sedge,

panicum, bluestem, lespedeza, tickclover, goldenrod, pussytoes, and aster; many more are

abundant locally.

Fauna,—The fauna of the oak-hickory ecosystem is similar to that of other eastern

hardwood and hardwood-conifer areas and

varies somewhat from north to south. Important animals in the ecosystem include the

white-tailed deer, black bear, bobcat, gray fox,

raccoon, gray squirrel, fox squirrel, eastern

chipmunk, white-footed mouse, pine vole, shorttailed shrew, and cotton mouse.

Bird populations are large. The turkey, ruifed

grouse, bobwhite, and mourning dove are game

birds in various parts of the ecosystem. Breeding bird populations average about 225 pairs

per 100 acres and include some 24 or 25 species.

The most abundant breeding birds include the

cardinal, tufted titmouse, wood thrush, summer

tanager, red-eyed vireo, blue-gray gnatcatcher,

hooded warbler, and Carolina wren. The box

turtle, common garter snake, and timber rattlesnake are characteristic reptiles.

Soils,—The soils of this ecosystem are varied.

The northeastern oak-hickory forest and the

northeastern portion of the Appalachian oak

forest are on Inceptisols and Ultisols. Soils of

the smaller Black Belt area are largely Ultisols.

The soils of the largest community in the ecosystem, the oak-hickory forest, are mainly Mollisols and Alfisols in the north and Ultisols in

the central portion. Two "fingers" of the oakhickory forest reaching into southern Texas

coincide with areas of Alfisols; Vertisols on

all sides are in other ecosystems.

Land use,—Small general farms characterize

much of the area, but there are also large dairy

and livestock farms. Tobacco is an important

cash crop in the east and cotton, in the west.

The steeper slopes, accounting for almost half

the area, are mainly in forest, which is used for

both recreation and timber production. A large

part of the Nation's coal is mined in this

ecosystem.

Productivity Classes

Herbage and browse production varies

greatly in this ecosystem, ranging from 200 to

11
3,000 pounds per acre. The variation is due to

differences in the crown cover of hardwoods

and in the production capabilities of sites. The

data on herbage production in the following

paragraphs include only those yields achieved

on land in natural cover—they do not include

yields achieved when low-grade oak-hickory

forests are converted to grasslands. Such grasslands could logically constitute another productivity class with yields ranging from 3,000 to

6,000 pounds per acre.

Class 1.—The vegetation of the oak-hickorybluestem mosaic occurring on the Cross Timbers and the glacial till area south of the Great

Lakes characterizes the highest productivity

class of this ecosystem. This vegetation is characteristically a transition between hardwood

forest and prairie biomes. Herbage yields vary

from 3,000 to 6,000 pounds per acre and average about 4,500 pounds per acre. The major

trees are mainly oak and hickory; mixtures of

maple, oak, and elm are more common in northern parts than elsewhere. The major grass species are those associated with the tail-grass

prairie; namely, big and little bluestem, Indian

grass, switchgrass, and side-oats grama. There

is a wide variety of forbs in this part of the

ecosystem.

The soils are highly variable but are mainly

Mollisols (Argiudolls that have a subsurface

horizon in which clay has accumulated) in the

northern part and Alfisols (Paleustalfs plus

Ustorthents which also have a subsurface horizon in which clay has accumulated) in the southern Cross Timbers area. Large areas of Inceptisols (Ustochrepts, shallow soils extending 20

inches to bedrock) also occur in the southern

part (Cross Timbers).

About 25 percent of the area of the northern

oak-hickory-bluestem mosaic is in tame or

native pasture and 10 percent is in woodland.

The remainder is in cash crops. About 50 percent of the southern part of this ecosystem

(Cross Timbers) is rangeland and open woodland; the remainder is in small grains and other

cash crops.

Class ^.—The vegetation that characterizes

productivity class 2 of this ecosystem is that of

the Black Belt. Yields of browse and herbage in

this class range from 1,500 to 3,000 pounds

per acre. The vegetation of this area is highly

variable, ranging from almost open bluestem

prairie to dense forest of tall or medium-height

broad-leaved deciduous trees. There are sporadic concentrations of redcedar on calcareous

rock outcrops. The major herbage plants are big

and little bluestem, switchgrass, Indian grass,

and a mixture of forbs and deciduous trees.

The most common trees are sweetgum, post oak

and other oaks, and hickory. Low-growing trees

and shrubs include winged elm, ash, and dogwood.

The soils are variable and include Vertisols

(Chromuderts plus Eutrochrepts, gently sloping and clayey), Inceptisols (Eutrochrepts plus

Chromuderts, gently sloping and usually moist

and high in content of bases), and Ultisols

(Paleudults, which are moderately sloping,

have a thick horizon of accumulated clay, and

are low in content of bases, plus Fragiudults,

which are gently sloping and have a fragipan).

Most of the Black Belt is in farms, one-fifth

being used for cropland, two-fifths for forests,

and the remainder for pastures and urban uses.

Ckss^.—The open meadows of the oak and

oak-hickory forests of the Great Smoky Mountains and the Ozark Plateaus characterize productivity class 3. Herbage production ranges

from 1,200 to 1,800 pounds per acre, averaging

about 1,500 pounds. The major herbaceous

plants are bluestems, poverty oatgrass, panicgrass, and three-awns. Forbs are less common.

Blackberry, sassafras, and persimmon are the

major browse plants.

The soils are Ultisols (Paleudults plus Fragiudults) and Inceptisols (Dystrochrepts plus

Fragiochrepts) which are soils with fragipans

that restrict tree roots but support low-growing

plants.

Class 3 areas are usually small and are used

mainly for pasture or hay production.

Class ^.—The vegetation within the forest

proper (excluding open meadows) of the

Appalachian oak forest and the oak-hickory

community of the Ozark Plateaus characterizes

this productivity class.

In the Appalachian oak forest community,

herbage and browse production (mainly

browse) varies from 500 to 800 pounds per

acre, averaging 650 pounds per acre. The major

tree species are white oak, northern red oak,

and white ash. Associates are red maple, yellow

birch, aspen, black cherry, and butternut in the

northern parts and yellow buckeye^ yellow

birch, sugar maple, and black cherry in the

middle and southern parts. White ash is less

important or is absent in the southern areas.

The major plants of the shrub strata are viburnum, sassafras, mountain laurel, rhododendron,

madrone, blueberry, blackberry, sedge, sorrel,

cinquefoil, fern, and clubmoss.

The soils of the Appalachian oak forest are

mainly Ultisols (Hapludults plus Dystrochrepts

and Paleudults) in the southern part and Inceptisols (Dystrochrepts) and Spodosols (Haplorthods plus Haplaquepts and Fragiochrepts)

in the north. All are moderately sloping to

steep.

About half the oak forest area is in forest or

farm woodlots, and one-fourth to one-third is in

cropland and pasture. Cropland and pasture

are more more common in the northern parts.

In the oak-hickory forest community of the

Ozark Plateaus and the interior low plateaus.

12
Figure 6.—^A mixed oak stand in the oak-hickory ecosystem.

"<.^ '

F-617742

13
combined herbage and browse yields are 200 to

300 pounds per acre. The major trees are black,

red, white, post, and blackjack oak; black, bitternut, and shagbark hickory; and elm. The

major shrubs and vines are blueberry, wild

grape, blackberry, poisonivy, woodbine, greenbriar, and dogwood. Herbaceous plants include

sedge, panicum, tickclover, goldenrod, pussytoes, and aster.

The soils are mainly Ultisols (Hapludults

plus Hapludalfs and Paleudults, moderately

sloping to steep). Some are Ultisols with a

fragipan (Fragiudults).

About three-fifths of the oak-hickory forest

area is in forest or woodland, and the other

two-fifths is used for cropland and pasture.

Conversion of forest land to grassland has

become increasingly common in this area.

NO. 16.—THE OAK-GUM-CYPRESS ECOSYSTEM

Physiography.—The oak-gum-cypress ecosystem is characterized by the vegetation of the

Mississippi Valley and other bottom lands in

every Southern State, the cypress savanna west

of the Everglades in Florida, the mangrove

swamps south of the Everglades, and the east

coast of Florida, Georgia, and the Carolinas.

Many of the rivers that cross the Coastal Plain

province have little drop in elevation—^the Mississippi River drops only 7.5 inches per mile

from Memphis to Vicksburg—and are meandering. The rivers have created large alluvial

plains. The largest plains are along the Mississippi River and extend from the Gulf of Mexico

to the Ozark-Ouachita Highlands and northeastward to Indiana. Other river fiood plains

are much smaller but in aggregate constitute

several million acres.

The alternating drylands and wetlands west

of the Everglades are known as the cypress

savanna, which is a monotonous flatland, very

few feet above sea level. Outcrops of dense,

fine-grained limestone are scattered through

the area, but these do not affect the flatness of

Figure 7.—A forest of live oaks, draped with Spanish moss, in the oak-gum-cypress ecosystem.

F-601614

14
the plain. The mangrove swamps of southern

Florida are an extension of the Everglades into

the ocean. Salt water invades that part of the

coastline, making it different from the Everglades and the cypress savanna.

Climate,—Most of this ecosystem has a moist,

mild climate, the frost-free season ranging from

200 days to practically all year at the tip of

Florida. Precipitation ranges from 60 inches

in Florida to about 35 inches at the northern

extremity of the ecosystem in Indiana. More

than half the precipitation comes in the warmest months, and in most of the area rainfall

exceeds evaporation during the frost-free

season.

Vegetation.-—The vegetation of this ecosystem varies considerably, but the dominants are

of tree life-form. It is made up of bottom-land

forests in which 50 percent or more of the stand

is túpelo, blackgum, sweetgum, oak, and baldcypress, singly or in combination—except

where pines comprise 25-49 percent of the

stand (in which case the ecosystem is oak-pine).

Common associates include willow, maple, sycamore, cottonwood, and beech. Most species are

broad-leaved deciduous trees. Trees of the

mangrove swamp are mainly black mangrove

and red mangrove. The vegetation of the

cypress savanna is dominated by needle-leaved

deciduous trees and some broad-leaved evergreen or deciduous trees and shrubs. The trees

and shrubs occur in groves surrounded by open

grassland dominated mainly by three-awn species. Mangrove swamps are often flooded by

tidewater; the cypress savanna is flooded less

frequently and only by fresh water.

Fauna,—This ecosystem is the most fertile

and productive of southern habitats for wildlife. In times past, large animals, such as the

deer, elk, black bear, mountain lion, bobcat, and

wolf, inhabited the forest. Presently, the whitetailed deer is common in most areas. Other

mammals include the gray fox, gray squirrel,

fox squirrel, raccoon, opossum, striped skunk,

eastern cottontail, swamp rabbit, and many

small rodents and shrews.

Birds include wild turkeys and, in the flooded

areas, ibises, cormorants, herons, egrets, and

kingfishers. Among the numerous species of

birds in the area, the ivory-billed woodpecker,

Bachman's warbler, and the southern bald

eagle are classed as endangered species. The

Carolina parakeet is extinct. Many species in

the mangrove swamps and the cypress savanna

are the same as those in the Everglades, in the

wet grasslands ecosystem. Common mammals

in the mangrove area are the fox squirrel and

raccoon. Nesting birds include the mangrove

cuckoo and various herons and egrets. The key

deer is very scarce and is classed as an endangered species.

Soils,—Soils of this ecosystem are varied. In

the largest area, the Mississippi bottom land,

they are Mollisols, Alfisols, and, primarily,

Inceptisols. The soils of the small area in southern Florida are primarily Inceptisols. In the

many bottom lands extending inland from the

Atlantic coast, the soils are mainly Ultisols,

smaller areas of Inceptisols being near the

coast.

Land i¿se.—Nearly all of the area is in farms.

The wettest parts that are not artificially

drained, about 10 percent of the area, remain in

forests. The remainder is evenly divided

between cropland and pasture. Cotton, soybeans, and corn are major crops in most of the

region; rice and sugarcane are important

locally.

NO. 17.—THE ELM-ASH-COTTONWOOD ECOSYSTEM

Physiography,—The elm-ash-cottonwood

ecosystem occurs in narrow belts along major

streams or scattered areas of dry swamps. The

major portion is on the lower terraces and

flood plains of the Mississippi, Missouri, Platte,

Kansas, and Ohio Rivers from the Dakotas,

Minnesota, and Ohio south through Kansas and

Missouri. The ecosystem also is scattered

throughout the area including States adjacent

to the Great Lakes and extending to the east

coast, where it occurs on dissected glacial-till

plains.

Climate,—The ecosystem crosses several climatic zones. It is characteristic of sites that

are moist as a result of either flooding or precipitation. Average annual precipitation varies

from 10 inches near the foothills of the Rocky

Mountains to 50 inches in the southern and

northeastern areas. Temperatures vary considerably, the January mean daily low ranging

from zero in the north to 30° F in the south.

The average frost-free period varies from 100

days in the north to 200 days in the south.

Vegetation,—The vegetation of this ecosystem is a tree life-form of low to tall broadleaved deciduous trees, varying from open to

dense and often accompanied by vines. Cottonwood species usually dominate the ecosystem

and often occur in pure stands. Cottonwood is

most common along the streams. Swamp cottonwood is more common in other places. Common associates in the north are willow species

and green and white ash. Sycamore and sugarberry are common associates in the south. Other

common associates are willow, sycamore, beech,

and maple. The cottonwood-willow stage is

15
Figure 8.—A stand of ash in the elm-ash-cottonwood ecosystem.

F-437117

short lived. This stage is followed by the river

birch and silver maple-American elm types in

the north and by the sycamore-pecan-American

elm or sugarberry-American elm-green ash

types in the south.

Fauna.—Since this ecosystem is far flung

and is in the main flood plains of rivers dissecting a number of other, quite different ecosystems, the fauna is varied and, in many cases,

influent from the surrounding ecosystems.

Forest-edge animals and birds are common,

and numerous ones include the cottontail, bobwhite, white-tailed deer, raccoon, red fox,

coyote, striped skunk, spotted skunk, meadow

jumping mouse, fox squirrel, and ground squirrels. The sharp-tailed grouse inhabits grassy

areas and open areas in the forest. The ruffed

grouse is also present. Other birds include the

catbird, goldfinch, yellow-billed cuckoo, indigo

bunting, cardinal, lark sparrow, mockingbird,

common crow, blue jay, robin, ruby-throated

hummingbird, and Cooper's hawk.

Sails.—The soils are mainly MoUisols (Haplaquolls plus Udifluvents, Hapludolls, and Hapludalfs) which are seasonally wet and have a

thick, nearly black surface horizon and gray

subsurface horizons. The materials in the horizons have been altered or removed, but no clay

or calcium carbonate has accumulated.

Land ttse.—At least 30 percent of this ecosystem is in forest, mainly as small woodlots

on wet bottom land and steep slopes bordering

stream valleys. The rest is cropland devoted

primarily to corn, soybeans, oats, and other feed

grains. Much of the grain is fed to beef cattle

and hogs on the farms where it is grown.

NO. 18.—THE MAPLE-BEECH-BIRCH ECOSYSTEM

Physiography.—The maple-beech-birch ecosystem is best developed in the New England

States. Typically, it occurs on open high hills

and low mountains. Only about 20-30 percent

of the area is gently sloping. Ridges rise 500 to

3,000 feet above the broad valleys. Farther

west, in the Lake States, the ecosystem occurs

on irregular plains and tablelands. There, SOSO percent of the area is gently sloping and

local relief is normally 100-300 feet.

16
Climate.—Mean annual precipitation ranges

from 40 to 48 inches and is about 41 inches at

central locations. The average annual snowfall

of 72 inches covers the ground for about 87

days each year. The number of freeze-free days

ranges from 120 to 150 per year. The mean

daily maximum temperature is 24°-36° F in

January and 74°-80° F in July. The corresponding minimum temperatures are 4°-18° F

and 52°-60° F. Potential évapotranspiration is

17-28 inches. The mean annual v?ater surplus

*3 10-34 inches.

Vegetation.—^A forest is classified as being

in this ecosystem when 50 percent or more of

the stand is maple, beech, or yellow birch, singly

or in combination. Common associates include

hemlock, elm, basswood, and white pine.

Fauna.—The white-tailed deer occurs

throughout much of the maple-beech-birch ecosystem. The hardwood forest and the openings

and farms within it provide food and cover for

a varied fauna. The black bear is present in

many areas. The wolf is no longer common, but

the red fox and gray fox are rather widespread,

as is the bobcat. Several species of squirrels are

in the forest, and a number of smaller rodents

inhabit the forest floor.

The ruifed grouse is widespread, and the

bobwhite inhabits the interspersed farmlands

and forest openings. Songbirds include the

ovenbird, red-eyed vireo, hermit thrush, scarlet

tanager, blue jay, black-capped chickadee, wood

pewee, and magnolia warbler.

Soils.—Typical soils have a low supply of

bases and a subsurface horizon that is dense

and brittle but not indurated or that contains

an accumulation of organic matter and iron and

aluminum compounds (Fragiorthods and Haplorthods). Other major soils have light-colored

surface horizons and a subsurface horizon that

is dense and brittle but not indurated (Fragiochrepts).

F-S22874

Figure 9.—A mixed stand in the maple-beech-birch ecosystem. The largest trees are sugar maples. Other trees are

yellow birch. The saplings are beech. The ground vegetation is largely a mixture of young trees and hobblebush.

17
Land use.—Much of the area is in farms.

Feed grains and forage for dairy cattle are the

principal crops. Potatoes are important locally.

The steeper land is mainly forested, produces

significant amounts of timber, and is an important recreation resource.

NO: 19.—THE ASPEN-BIRGH ECOSYSTEM

Physiography.—Th^ aspen-birch ecosystem

lies mainly within the Great Lakes section of

the Central Lowland east of the Mississippi

River and extends from western Minnesota to

Lake Erie. This area is characterized by a great

variety of features of recent glacial origin. In

addition to moraines and outwash plains, thousands of lakes and large areas of swamps are

in the area. The underlying rock strata of the

area are buried by thousands of feet of glacial

till. These strata span the ages from Cambrian

to Carboniferous. Three strong formations of

dolomite, limestone, and sandstone form outcrops on the edges of two cuestas. The intervening weak beds do not form any particular features. Elevations vary from 600 to 1,500 feet.

CZimaie.—The areas occupied by this ecosystem have a moist and cool climate. The frostfree period varies from 100 to 140 days. Average annual temperatures are 35''-47'' F. Annual

precipitation is 30-35 inches, of which 40-66

percent falls during the warmest months. Precipitation during the frost-free season ranges

from about 80 percent of the evaporation potential to about equal that potential.

Vegetation.-—This ecosystem is characterized

by forest in which 50 percent or more of the

stand is aspen, balsam poplar, paper birch, or

gray birch, singly or in combination. Common

associates include maple and balsam fir. Major

aspen species in the Great Lakes area are bigtooth and quaking aspen. Paper birch is a common associate. Balsam poplar is important only

along streams and the margins of swamps.

Fat^TMi.—The fauna of the aspen-birch ecosystem is similar to those of the spruce-fir and

white-red-jack pine ecosystems, with which

this ecosystem is intermingled. The white-tailed

deer and black bear are common. The coyote,

bobcat, great horned owl, and other predators

feed on a variety of small mammals. The ruffed grouse is present. Among the songbirds are

the tufted titmouse, blue jay, hairy woodpecker,

downy woodpecker, wood thrush, eastern wood

pewee, goldfinch, catbird, and red-eyed vireo.

Sot7s.-—The aspen-birch ecosystem occurs on

a wide variety of soils, but they are mainly

within three orders. The better drained soils

are mostly Alfisols, and the wetter, poorly

drained soils are Entisols and Mollisols.

Land use.-—M.0YBt\í2LXí 80 percent of the area

is in forest. Lumbering, recreation, and mining

are major industries. Feed grains and forage

for dairy cattle and other livestock are the main

products of cropland. Potato growing is important locally.

NO. 20—THE DOUGLAS-FIR EGOSYSTEM

Physiography."^The Douglas-fir ecosystem

encompasses one of the larger blocks of western

timber in that it includes much of the mountains in western Oregon and western Washington and extends well south into the northern

California Coast Ranges. It is an extensive

ecosystem, for there are large acreages of it in

the Northern Rocky Mountains and lesser scattered areas in the Blue Mountains of Oregon

and the Middle and Southern Rocky Mountains.

The elevational range is great, from 500 feet

up into the high mountains.

Climate.—The length of the frost-free season

is 200 days in western coastal areas and 160

days in the rest of western Oregon and Washington. In the rest of the ecosystem, the frostfree season is about 80 to 120 days. Average

annual precipitation is 40 to 80 inches in the

extreme west and 20 to 30 inches in most of the

interior portion of the ecosystem. In the

extreme west 50 to 60 percent of the total

precipitation occurs during the period December to March. In the rest of the ecosystem, only

25 to 40 percent of the precipitation occurs in

the cordest months. The amount of precipitation

during the frost-free season m equal to, or not

less than, 40 percent of the evaporation, in

western Oregon and western Washington. In

the rest of this ecosystem, precipitation during

the frost-free season is only 30 to 40 percent of

the evaporation potential.

Fe^etaiioM.—This ecosystem is characterized

by forest consisting of 50 percent or more

Douglas-fir, except where redwood, sugar pine,

or western white pine Gomprise 20 percent or

more of the stand. Most common ecological

descriptions of one of the largest blocks of timber in western Oregon and Washington define

it as subclimax stands in areas where the climax is western hemlock-western redcedar.

Common shrubs in the ecosystem are of the

genera of maple, rockspirea, filbert, blueberry,

snowberry, barberry, currant, blackberry, ninebark, rose, and spirea. Herbage includes grass

and other vegetation having a grasslike growth

form, especially in the stands in interior States.

18
F-502403

Figure 10.—A young stand of paper birch in winter, in the aspen-birch ecosystem, in the Great Lakes area.

19
95-G-48608

Figure 11.—A stand of old Douglas-firs with western hemlock in the understory, in the Douglas-fir ecosystem in the

Pacific Northwest

20
Here, pinegrass and Carex concinnoides are

present.

Fauna,—Common large mammals in this ecosystem include elk, deer, and black bear. Grizzly

bear and moose are in the northern Rockies.

Blue and ruffed grouse are present. Most of the

northwestern part of the ecosystem has hawks

and owls. Mammalian predators include mountain lions and bobcats. Small mammals include

mice, squirrels, marten, chipmunks, and bushytailed wood rats. Some of the more common

birds are the chestnut-backed chickadee, redbreasted nuthatch, gray jay, and Steller's jay.

Soils,—In western Washington and Oregon

the soils of this ecosystem are Inceptisols and

Ultisols. In the northern coastal area of California they are Ultisols. In the Blue Mountains

of Oregon, the soils are Mollisols with an overburden of very absorptive Vitrandepts. In the

northern Rockies the soils are Inceptisols (including considerable areas of Vitrandepts),

Alfisols, and Mollisols. In the Middle and Southern Rocky Mountains, the soils are Mollisols,

Entisols, and Alfisols.

Land use,—About 75 percent of the land area

is forested, and lumbering is a major industry.

Less than 20 percent is in crops or improved

pasture. Fruit, vegetables, and grain are the

major crops. Forage and feed grains occupy

large acreages.

The best sites in this ecosystem have historically been used for timber production in

western Washington, Oregon, and California.

Use of the land for livestock production is not

so well known. However, there are now more

sheep in western Oregon and Washington than

in the range flocks of the eastern parts of these

States. The big increase in sheep raising has

been in farm flocks in the lowlands on land

enclosed with woven-wire fences. However,

some privately owned cutover lands in the hills

and mountains have been converted to seeded

ranges for livestock, and the favorable precipitation has permitted high stocking rates to be

successfully achieved—1 to 2 animal unitmonths (AUM's) per acre.

Without management of the average tract of

old cutover land, it usually becomes uneconomical to use it for grazing, because of the

invasion of bracken and brush. Under serious

and responsible management, there are some

possibilities for more and better use of forest

lands for livestock. Chiefly, there is the possibility of grazing recently logged lands in combination with seeded land at lower elevations.

A relatively small number of cattle- or sheepraising operations presently make use of

recently logged-over lands, yet it is possible to

start grazing patch clearcuts within 2 or 3 years

after logging (as soon as new tree seedlings

are established) and continue grazing for about

15 years, or until the tree canopy closes.

Land use in this ecosystem in the Blue Mountains of Oregon and in the northern Rockies is

similar to the grazing-timber growing relationship in the ponderosa pine ecosystem. "Jungling" or "brushing-up" is, however, more

prevalent in interior Douglas-fir stands than in

the ponderosa pine stands. The pine stands are

estimated to be 60 percent jungled, whereas

interior Douglas-fir stands are about 90 percent

jungled. Suppression of timber growth by too

great a density of trees has been slower to occur

in the stands of Douglas-fir than in the stands

of pine because of the former's tolerance to

shading. Nevertheless, wherever the stand density is excessive in this ecosystem, forage production has been reduced to 150 pounds per acre.

Productivity

Grazing in major portions of this ecosystem,

in western Washington, western Oregon, and

western California, is usually confined to patch

clearcuts and lands converted to pasture by

logging and grass seeding. Under good management, grass production of 1,000 to 3,000 pounds

per acre can be achieved. With no opening of

the tree canopy, herbage production is 50 to

150 pounds per acre.

NO. 21.—THE PONDEROSA PINE ECOSYSTEM

Physiography,—Since ponderosa pine has a

rather wide range of adaptability and can

dominate some of the less mesic true forest

sites, it occupies low mountains and foothills

in rnany places; yet in mixtures with other

species, it is found at moderate elevations. The

extensive distribution of ponderosa pine and

associates includes parts of 14 western States

from Nebraska to the Pacific coast and from

Arizona to Canada. It is the largest western

forest type in the United States. Local topography can be gentle, as on plateau tops and

low mountains, or it can be steep, as on canyon

walls and faces. Semiarid, low mountain sites

are common, but it is difficult to characterize

the physiography of the ecosystem because it

varies greatly.

Climate,—The length of the frost-free season

at any location in the ecosystem depends largely

upon the latitude and elevation. In general, in

much of the northern area the frost-free period

is 120 days, whereas in many foothill areas and

in parts of the Sierra and the Gila Mountains

of the Southwest, it can be 240 days.

Annual precipitation is about 15 to 20 inches

in the more pure pine areas, but where there

21
are combinations of pine and other conifers at

moderate elevations, the precipitation can total

30 inches. In the far western sector, only 25

percent of this moisture falls in the warmest

months. In the Northern Rocky Mountains, 40-

50 percent of the precipition occurs in the

warmest months. In the middle to southern

Rockies, 66 to 75 percent occurs in the warmest

months. In the southern areas and those at

low elevations, precipitation during the frostfree season is only 20 percent of the evaporation potential. In northern areas precipitation

during the growing season may be as high as

40 percent of the evaporation potential.

Vegetation.—-By definition, ponderosa pine

forest is 50 percent or more of one of these

pines: ponderosa pine, Jeffrey pine, sugar pine,

limber pine, Arizona ponderosa pine, Apache

pine, or Chihuahua pine. The exceptions are

those situations where western white pine or

sugar pine comprises 20 percent or more of the

stand ; then these species control the name of

the forest.

The impact of logging and ecological dynamics can cause some problems in maintaining

good delineation of the ponderosa pine ecosystem. This ecosystem is idealized as open and

parklike with an excellent ground cover of

grasses, sedges, and forbs or with an understory of shrubs of low to medium height. The

shrubs, however, may vary from antelope bitterbrush in Oregon to bearmat in the Sierra

Nevada in California. In perhaps 60 percent of

the area, the idealized open character of the

ponderosa pine ecosystem has changed to that

of a dense and growth-retarded stand,^ particularly in the Pacific Northwest.

Fauna,—In the ponderosa pine ecosystem,

the major mammalian influents are the Rocky

Mountain elk, mule deer, mountain lion, and

coyote. Animals of less importance include the

bushy-tailed wood rat, white-footed mouse, bobcat, rock squirrel, cottontail, porcupine, mantled

ground squirrel, Kaibab squirrel, and chipmunks. The Kaibab squirrel is rare. It is

endemic to this ecosystem on Arizona's Kaibab

Plateau.

The most abundant and important resident

birds in the ponderosa pine ecosystem include

the pygmy nuthatch, long-crested jay, sharpshinned hawk, Rocky Mountain nuthatch, mountain chickadee, Cassin's purple finch, redshafted flicker, red-backed junco, western goshawk, and western red-tailed hawk. Birds that

are common during the summer include the

chestnut-backed bluebird, Audubon's warbler,

Natalie's sapsucker, western chipping sparrow,

horned owl, and band-tailed pigeon.

3 "Dense and growth-retarded" means 2,000 to 10,000

pine stems per acre instead of 125 per acre. In most

such cases, growth rings are 20 to 40 per inch instead of

15 or fewer rings per inch.

Soils.—The soils occupied by the ponderosa

pine ecosystem vary tremendously. Along the

western edge of the Columbia Plateau and the

east slope of the Cascade Mountains, they are

Mollisols, Inceptisols, Entisols, and Aridisols.

In northern and eastern California, ponderosa

pine stands are associated with Ultisols. At the

northern edge of the Columbia Plateau (Okanogan Highlands) and in much of the Northern

Rocky Mountains, pine and the related forest

types occur on Inceptisols; the soils of the rest

of these areas are largely Alfisols and Entisols.

In the Blue and Wallowa Mountains of eastern

Oregon, pine stands occupy Mollisols. In the

Middle and Southern Rocky Mountains, pines

and associates are on Mollisols, Aridisols, Entisols; and Alfisol&. Pine stands in the Gila Mountains are largely on Mollisols. The small stands

of pine in the Great Basin are on Aridisols.

Land use.—Ponderosa pine lands continue to

be producers of softwood that is highly desired

for either millwork or framing. The forage supply within the ecosystem has been highly prized

for summer range, since the land is usually high

enough to get good precipitation and the forest

soils are deep enough to store sufficient water

for growing timber and good ground cover.

These precipitation and soil characteristics

make the ecosystem productive of forage during the hot months when range forage at lower

elevations has dried.

Currently forage production in the ponderosa

pine ecosystem is lagging behind its potential,

and the total productivity is suppressed enough

to create à seasonal shortage of summer range

for livestock. In some areas this shortage is

such that if ranchers stock to fully use the

winter, spring, and fall range, there is a 40 to

50 percent shortage of summer range. Many

ranchers are forced to meet this situation by

using spring and fall range also as summer

range. Ranchers operating this way have to

accept substantial weight losses in brood cows

by fall of each year, and they have to accept

calf crops only about 75 to 83 percent of the

calf crops of ranchers with true summer range

who maintain 1,000- to 1,400-pound cows with

a 90 percent calf crop.

The mountain range of the ponderosa pine

and Douglas-fir ecosystems is a prime summer

range for a high proportion of the mule deer

andis a spring and fall range for elk. Approximately 20 to 30 percent of the herbage is

reserved by land managers for use by big

game. However, this is not to say that this

range is critical for big game; for these animals

the winter forage supply of low-elevation shrub

and bunchgrass ranges is critical.

Productivity

Excessive density of tree stands and consequent arrested tree growth in some parts of

22
r^^^-'-t-'^.'.'V^

F-469737

Figure 12.—A parklike stand of timber and ground cover of grass in the ponderosa pine ecosystem in the Pacific

Northwest.

the ponderosa pine ecosystem make it impossible to estimate the potential timber and forage

productivity of many sites. At such locations

an inverse relationship can be found between

the density of the tree stand and forage

production.

About 500 to 600 pounds of herbage per acre

is commonly produced in open stands of mature

pine with about 200 saplings per acre. In stands

that have an understory of tree reproduction

numbering 2,000 stems per acre, the herbage

production is only about 250 pounds per acre.

At about 5,000 stems or more per acre, herbage

production can be 0 to 50 pounds per acre.

When pure stands of ponderosa pine are thinned

to approximately 75 to 100 stems per acre,

herbage production of 850 pounds per acre is

obtainable. On reseeded skid trails it is possible

to produce 1,000 to 2,000 pounds of herbage

per acre.

The quality of herbage for livestock and game

is improved by the timber stand improvement

practice of thinning; that is, the nondigestible

fraction of forage decreases and the proportion

of carbohydrates increases. The floristic composition of the herb and shrub understory in

pine forests seems to vary with several factors,

including the overstory. In the Northwest,

grasses and sedges of such genera as Calamagrostis, Carex, Agropyron, Festuca, Muhlenbergia, Poa, Stipa, and Danthonia constitute

10 to 40 percent of the composition. Shrubs are

very conspicuous in certain areas and include

such genera as Purshia, Ceanothus, Rosa, Symphoñcarpos, Holodiscus, Spirea, Salix, and

Arctostaphylos. Various forbs are common.

23
NO. 22.—THE WESTERN WHITE PINE ECOSYSTEM

Physiography,—The western white pine ecosystem mainly occurs in the high mountains of

the Northern Rocky Mountains of western

Montana and northern Idaho. It is also in scattered small areas in the Cascade Mountains of

Oregon and Washington. Less than 20 percent

of the total area is gently sloping, and local

relief is over 3,000 feet. Elevations are mostly

4,000 to 8,000 feet

Cíimaíe.—Annual precipitation in this ecosystem is 20 to 30 inches; of this, 60 to 65 percent occurs during the warmest months. During

the frost-free season, precipitation is 20 to 40

percent of the evaporation potential. The length

of the frost-free period is 80 to 120 days.

Vegetation,-^Forests in which 20 percent or

more of the stand is western white pine or sugar

pine characterize this ecosystem. Küchler's

classification of cedar-hemlock-pine forest corresponds with this ecosystem. Daubenmire and

Daubenmire (1968) would classify western

white pine as being in various western redcedar

habitats, but also as being serai to some western hemlock and true fir habitats. In summary,

western white pine is sometimes found in pure

stands yet commonly occurs in mixtures with

other conifers. Shrubs and forbs are prominent

in the understory, whereas grasses and sedges

are minor.

Fauna,—The fauna of the western white

pine ecosystem is similar to that of the ñrspruce ecosystem. The ecosystem is noted for

its population of big game, particularly the

Rocky Mountain elk and mule deer. Smaller

mammals include the snowshoe hare, longtailed weasel, marten, coyote, bobcat, and various mice and shrews. The black bear is present.

The many birds include the ruffed grouse,

chestnut-backed chickadee, red-breasted nuthatch, and Swainson's thrush.

Soils,—Most of the soils have formed from

ashy materials or have low bulk density and

large amounts of amorphous materials, or both.

Horizons are weakly developed (Andepts). The

most productive sites in this ecosystem have

moist but well-drained soils and occur in valleys

and on moderate to gentle slopes with northern

exposures.

Land lise,—Heavy forests cover much of the

land; croplands occupy less than 2 percent of

the ecosystem. The forests are important for

timber production as well as summer cover for

wildlife—the area is famous for its elk hunting.

Wood of western white pine is soft and highly

'"workable," like that of eastern white pine;

thus, it is valued for a variety of millwork

items. The most productive forage sites are

usually limited to logged-over areas or natural

meadows and openings that are adjacent to, or

interspersed within, the general forest type.

NO. 23.—THE FIR~-SPRUCE ECOSYSTEM

Physiography,—The fir-spruce ecosystem lies

within the Sierra-Cascade and the Northern,

Middle, and Southern Rocky Mountains provinces. It is normally the highest forest zone in

the mountain ranges but varies from as low as

1,500 feet in the Northwest to as high as 12,000

feet in the Southern Rocky Mountains. Much of

the topography is rough and broken.

Climate,—Annual precipitation ranges from

somewhat less than 22 inches in the Rocky

Mountains to 50-75 inches in the Sierras. In

the Rockies 50-65 percent of the precipitation

falls in the warmest months, while in the

Sierra-Cascade Mountains province only 25-40

percent falls in the warmest months. Precipitation in the period December-March is 50-60

percent of the annual total in the SierraCascade Mountains and 15-25 percent in the

Rocky Mountains. During the frost-free season,

precipitation is 20 to 40 percent of the evaporation potential.

Vegetation,—The fir-spruce ecosystem is

characterized by open to dense forests of low

to tall needle-leaved evergreen trees and patches

of shrubby undergrowth and scattered herbs.

Fifty percent or more of the stand is silver fir,

subalpine fir, red fir, white fir, mountain hemlock. Engelmann spruce, or blue spruce, singly

or in combination-—except where western white

pine comprises 20 percent or more of the stand

(in which case the ecosystem would be classified as western white pine). Because of the

dense overstory and limited understory, heavily

stocked stands are usually not considered a

forage resource for domestic livestock unless

timber is harvested by patch clearcuts.

The usual dense stand produces about 0 to 50

pounds of herbaceous and shrub material. Patch

clearcuts or burns which are rehabilitated by

tree planting and grass seeding can produce

2,000 to 3,000 pounds of herbage per acre for

10 to 12 years.

Fauna,—Seasonally^ the fir-spruce ecosystem

and, in particular, the interspersed openings

and stream bottoms with broad-leaved woody

species such as aspen and willows are used by

moose, elk, mule deer, and white-tailed deer.

Mountain caribou originally wintered in Idaho,

Washington, and Montana; a few still do. The

wolverine, lynx, black bear, mountain lion.

24
F-37919B

Figure 13.—The shrub understory in this forest in the western white pine ecosystem provides good cover for wildlife.

25
Figure 14.—A stand of Pacific silver fir and noble fir in the fir-spruce ecosystem.

F-522875

26
coyote, and wolf occur in the ecosystem. The

grizzly bear is present, though in a fraction of

its original numbers and is classified as a rare

species. Grizzlies are about the only predator

of elk and possibly are a useful natural control

over excessively large elk herds.

Several of the species that have been mentioned use the fir-spruce ecosystem only seasonally, primarily as cover or in following

migratory routes. This isthe case with the mountain sheep and the mountain goat, which occur

more commonly in steep rocky areas. Among the

birds in the ecosystem are several of the blue

grouse and spruce grouse groups, ruffed grouse,

and various chickadees, nuthatches, bluebirds,

robins, and jays. Among the more common

rodents and lagomorphs are the porcupine,

beaver, snowshoe rabbit, squirrels, flying squirrels, pocket gophers, chipmunks, and various

species of mice.

Soils,—The soils of this ecosystem are

extremely varied. In the Northwest, Inceptisols

(Cryandepts and Cryumbrepts) predominate.

Ultisols occur in the Sierra Nevada Range.

Alfisols (Boralfs) are common in the Rocky

Mountains, and there are also significant areas

of Entisols. Areas of deep overburdens of

absorptive Vitrandepts are very productive

sites in eastern Oregon and the northern

Rockies.

Land í¿se.—Heavy forests cover much of

the ecosystem, and they are used as wildlife

habitats and watersheds and for recreation and

lumbering. There is virtually no cropland. Much

of the area is owned by the Federal Government. Grazing by domestic livestock is generally limited to natural parks and meadows

that occur within the forest matrix.

NO. 24.—THE HEMLOGK-SITKA SPRUCE ECOSYSTEM

Physiography,—The hemlock-Sitka spruce

ecosystem extends south from British Columbia

along the Oregon and Washington Coast Ranges

and occupies part of the Cascade Range in

Washington. The elevation ranges from 200 to

4,000 feet.

Climate,'—The length of the frost-free season

for that portion of the ecosystem along coastal

Oregon and Washington is about 200 days. The

portion in the northern Cascades has a frostfree season of about 120 days. Precipitation is

about 60 to 115 inches annually in western Oregon and Washington. In western Oregon and

Washington, about 60 to 70 percent of the precipitation occurs in the months of December to

March. In western Washington the amount of

precipitation is mostly equal to double the

evaporation potential. In western Oregon it is

80 percent of potential evaporation.

Vegetation,—This ecosystem is defined as

having 50 percent or more of the forest in

western hemlock or Sitka spruce or both. Other

tree species which may be present to a lesser

degree are Douglas-fir, grand fir, and western

redcedar. Common shrubs include the vine

maple, red whortleberry, Cascades mahonia,

California dewberry, and coast rhododendron.

Usual herbs are American twinflower, hollyfern,

cutleaf goldthread, and redwoods violet.

Fauna,—The most common large mammals

in this ecosystem include the elk, deer, black

bear, and moose. In the hemlock areas of the

northwestern portion, the red-tailed hawk,

screech owl, pygmy owl, and great horned owl

are avian predators. Mammalian predators

include mountain lions, bobcats, wolves, the

Pacific marten, and the western spotted skunk.

Smaller animals include the deer mouse, Douglas squirrel, bushy-tailed wood rat, Townsend's chipmunk, and coast mole. Among the

more common birds are the red crossbill,

chestnut-backed chickadee, red-breasted nuthatch, raven, gray jay. Steileres jay, hermit

warbler, western wood pewee, and pine siskin.

Blue and ruffed grouse are also present.

Soils,—Along coastal Oregon and Washington and in the northern Cascade Mountains,

the soils of this ecosystem are Inceptisols.

Land use,-^'Nearly all the area is in forest.

In the Pacific Northwest, most of the ecosystem

is privately owned. Lumbering is the major

industry. The narrow valleys and coastal plains,

about 5 percent of the total area, are cleared.

Hay for dairy cattle is the chief crop.

NO. 25.—THE LARCH ECOSYSTEM

Physiography,—The larch ecosystem occupies

the high mountains of eastern Oregon, northern

Idaho, and western Montana. Less than 20 percent of the area is gently sloping. Local relief

is over 3,000 feet. Larch commonly occupies the

upper slopes or northern exposures at lower

elevations—about 3,500 feet.

Climate,—The length of the frost-free season

in the ecosystem is 120 days in the Blue Mountains of eastern Oregon and 80 to 120 days in

the northern Rockies. Annual precipitation is

20 to 30 inches in eastern Oregon and 20 to 50

inches in the northern Rockies. Of this precipitation, 40 to 50 percent occurs in the period

27
F-70500

Figure 15.—A stand of western hemlock and Sitka spruce in the hemlock-Sitka spruce ecosystem. The large trees

are Sitka spruce.

28
F-500637

Figure 16.—Stand of young larch trees in foreground, in the larch ecosystem. In this ecosystem, local relief exceeds

3,000 feet.

December to March in the eastern Oregon area

and only 35 to 40 percent occurs in the coldest

months in the northern Rockies. During the

frost-free season, precipitation is 20 percent of

the evaporation potential in eastern Oregon

and 20 to 40 percent in the northern Rockies.

Vegetation.—This ecosystem is characterized

by forests in which 50 percent or more of the

stand is western larch, except where western

white pine comprises 20 percent or more of the

timber volume. Ecologically, larch is considered

serai to stands of grand fir and stands of

Douglas-fir. This ecosystem produces 75 to 150

pounds of understory herbage per acre. However, where it is patch clearcut, planted to trees,

and seeded to grass, it will produce 2,000 to

3,000 pounds of herbage per acre for 10 to 15

years. Understory species are commonly of the

genera found in spruce-fir stands and some

Douglas-fir stands.

Fauna.—The fauna in the larch ecosystem is

similar to the faunas of the Douglas-fir and

fir-spruce ecosystems. Larch, however, being a

deciduous conifer, lets more light into the stand

during part of the year. The difference in the

amount of light leads wildlife to prefer the

larch stands at times.

Soils.—In eastern Oregon, the soils of this

ecosystem are Mollisols, particularly on north

and northeast slopes where there is an overburden of deep, absorptive Vitrandepts. In the

northern Rockies they are Inceptisols, Alfisols,

and Mollisols.

Land use.—Much of the land is heavily

forested, affording wildlife habitats, providing

livestock forage, and offering opportunities for

recreation, as well as producing timber. Mining

is important in northern Idaho and western

Montana. A very small percentage of the land is

cropped. Forage and grain grown in some of the

valleys provide feed for dairy cattle and other

livestock.

29
NO. 26.—THE LODGEPOLE PINE ECOSYSTEM

Physiography.—The lodgepole pine ecosystem occupies sites on high mountains of Western States. It occurs even in some places where

less than 20 percent of the area is gently sloping

and at elevations ranging from 4,000 to 11,500

feet, with local relief over 3,000 feet. However,

the ecosystem is best developed on gentle

mountain slopes.

Climate.—Commonly, lodgepole pine is on

sites where the length of the frost-free season

is 80 to 120 days, but it seems to be tolerant of

frost at almost any time of year. This species

grows where the average annual rainfall is as

low as 20 inches, but it can grow well with 50

inches of precipitation. During the frost-free

season in lodgepole pine areas, precipitation is

commonly 20 percent of potential evaporation

and is often 40 percent. Lodgepole pine stands

are adapted to varied distribution of rainfall. In

the southern Cascade Mountains and the midSierras, lodgepole pine stands receive 50 to 60

percent of their annual precipitation in the

Figure 17 ^A stand of old lodgepole pines in the lodgepole pine ecosystem.

F-489697

30
period December to March. Yet, in the middle

Rockies they receive only 15 to 35 percent of

their precipitation in this period.

Vegetation.—This ecosystem is characterized

by forests in which 50 percent or more of the

stand is lodgepole pine. Ecologically, lodgepole

pine stands are serai to some of the western

interior coniferous forests. *'Doghair'' stands

often develop after fires. Understory species,

if present, are of about the same genera as

found in stands of western larch, spruce-ñr,

and interior Douglas-fir. Herbage production

can be 0 to 50 pounds per acre in dense stands

or 2,000 to 3,000 pounds per acre where clearcuts, burns, or conversions to a different coniferous stand are carried out. Of course, herbage

productivity in treated areas declines with

closure of the tree canopy and in 10 to 20

years will return to a very low level.

Fauna,—The lodgepole pine ecosystem has

about the same fauna as Douglas-fir, larch, and

spruce-fir forests of the same elevational zone.

Low productivity of understory flora in many

cases limits the number of animals that can be

supported. Islands of uncut lodgepole pine provide excellent escape routes and protective

refuges or cover for big game animals.

Soils,—In the Sierras, the lodgepole pine ecosystem occupies Ultisols. In the eastern Cascades of Oregon, it occupies Entisols. In the

Blue Mountains of eastern Oregon, lodgepole

pine grows best on Vitrandepts, which deeply

overburden bedrock or Mollisols. In the Rocky

Mountains, this ecosystem occupies Inceptisols,

Mollisols, and Alfisols.

Land use.—Much of the land of this ecosystem is forested. About 80 percent is owned by

the Federal Government. In addition to producing timber, the forest yields water, affords

wildlife habitats, and provides opportunities

for recreation. Several national parks are in

the area of this ecosystem.

NO. 27.—THE REDWOOD ECOSYSTEM

Physiography,—The redwood ecosystem

occupies only the low coastal mountains of

northern California and the southwestern portion of Oregon. Less than 20 percent of the area

is gently sloping. Local relief ranges from

1,000 to 3,000 feet.

Climate,—The climate is moist and temperate. Annual precipitation averages nearly

60 inches, of which 10-25 percent falls in the

warmest months and 60-70 percent in the

period December to March. Normal annual pan

evaporation is 40-50 inches. The amount of

precipitation is two and one-half to five times

the potential evaporation during the frost-free

season.

Vegetation,—The vegetation of this ecosystem is a dense forest of very tall, evergreen,

needle-leaved trees, sometimes with much

undergrowth—20 percent or more of the stand

is redwood. The dominant plants are redwood

and Douglas-fir. Other major components of

the vegetation include grand fir, salal. Pacific

waxmyrtle, coast rhododendron, western hemlock, box blueberry, and swordfern.

Fauna,—The Columbian black-tailed or coast

deer is present in the redwood ecosystem. Elk

use the ecosystem in some areas but are much

less numerous than in the past. Mountain lions,

bobcats, and black bears may be seasonally

active within the forest. The red-tailed hawk,

screech owl, and great horned owl feed on mice

and other small animals on the forest floor.

The sharp-shinned hawk and Cooper's hawk

prey chiefly on birds. The band-tailed pigeon

may occur as a summer resident. The blue

grouse is the most common ground-nesting bird.

Other characteristic birds include the pileated

woodpecker, gray jay, brown creeper, hermit

warbler, and red crossbill.

Soils,—The soils are Ultisols. Base saturation is low; organic matter content is high. A

relatively thin subsurface horizon of accumulated clay is present (Haplohumults).

Land use,—Most of the land is in privately

owned farms, ranches, or forest. Lumbering

is the major industry. Only about 10 percent

of the ecosystem is in grassland used for grazing. The cultivated land in valleys, less than 5

percent of the total area, is used mainly for

growing forage and grain for dairy cattle.

NO. 28.—THE WESTERN HARDWOODS ECOSYSTEM

Physiography.—The western hardwoods ecosystem occurs in northern California and southern Oregon on tablelands where 50-80 percent

of the area is gently sloping and the relief is

only 300-500 feet and on low mountains where

slopes are mostly steep and the local relief is

1,000 to 3,000 feet. It also occurs in the Rocky

Mountains, and this portion of the ecosystem

(mostly aspen areas) varies considerably.

Climate,—The west coast portion of this ecosystem has rainy winters and dry summers.

Annual precipitation ranges, on the average,

from 15 inches in California to 48 inches in

Oregon and occurrs mostly as rain between the

31
months of November and May. Normal annual

pan evaporation ranges from about 40 inches

in Oregon to nearly 100 inches in southern

California. Evaporation during the frost-free

season ranges from about two to five times the

potential evaporation. The climate of the vs^idely

scattered Rocky Mountain portions corresponds

to that described for adjacent or surrounding

ecosystems.

Vegetation.—This ecosystem is characterized

by forests in which 50 percent or more of the

stand is hardwood species—except where western white pine, sugar pine, or redwood comprises 20 percent or more of the stand (in

such cases the ecosystem is classified as western

white pine or redwood). The vegetation is a

forest of low to medium-tall, broad-leaved

deciduous or evergreen trees, sometimes with

an admixture of low to medium-tall needleleaved evergreens, often with an understory

of grass and shrubs.

In the California and Oregon portions of this

ecosystem, dominant species include Oregon

white oak. Coulter pine. Digger pine, coast live

oak, canyon live oak, blue oak, valley oak, and

interior live oak. In California this ecosystem

lies mainly between the annual grasslands and

the chaparral and mixed conifer zones. The

widely scattered Rocky Mountain and Plains

States "hardwood" portion of the ecosystem consists primarily of quaking aspen stands with an

understory of grasses, forbs, and shrubs. In

many places where the aspen stands are inclusions within areas of sagebrush or conifers,

they are important sources of food and cover

for wildlife. Cottonwood becomes dominant on

plains, more or less replacing aspen.

Fauna.—In California several subspecies of

the mule deer are numerous in various parts

of this ecosystem. The now-extinct California

grizzly was once numerous. An occasional black

bear comes down from forests at higher elevations. Mountain lions are no longer numerous;

the largest numerous predatory animals are the

coyote and the bobcat. Avian predators include

golden eagles and red-tailed and other hawks.

F-522876

Figure 18.—Some of the trees in this forest in the redwood ecosystem are more than a thousand years old.

32
Figure 19.—A representative scene in the western hardwoods ecosystem.

F-325590

Two endangered species, the California condor

and the San Joaquin kit fox, occur. California

quail are often abundant at lower elevations,

and mountain quail winter at the higher elevations. The striped skunk is widespread. Among

the more common small mammals are the

Beechy ground squirrel, kangaroo rat, pocket

gopher, and a number of types of mice. Also

occurring in this part of this ecosystem are

additional species found in the annual grasslands ecosystem.

The fauna of the Oregon oakwoods portion

of the ecosystem is somewhat similar to that

in the California portion, but species representative of the southern part of the California

oakwoods may not be present and more northern species, such as the ruffed grouse, are

present. Deer are common ; elk were numerous

in the past. The western gray squirrel frequents stands of Garry oak. The fauna of the

aspen portion of the ecosystem throughout the

Rocky Mountain area is essentially that of the

adjacent or surrounding ecosystems, but the

aspen stands serve as important areas of food

and shelter for many species of wildlife. Where

hardwood stands occur on river bottoms in the

plains, they are a home for many arboreal and

forest-edge species that are not present in the

surrounding open country.

Soils.—In Oregon the soils of this ecosystem

are deep and have well-developed illuvial horizons (Argixerolls). Drainage is generally good.

Farther south, in California, the surface horizons are somewhat lighter and lower in content

of organic matter, but the illuvial horizon of

accumulated clay is again present (Xeralfs).

Land use.—Livestock grazing in the ecosystem is limited to the more open portions of

stands adjacent to grasslands. Wildlife find

cover in the several variations of the ecosystem, and the aspen portions provide browse

for big game.

NO. 29.—THE SAGEBRUSH ECOSYSTEM

Physiography.—The sagebrush ecosystem is

prominent principally on the Columbia Plateaus, in the Northwestern States; in the central portion of the Great Basin, in Utah,

Nevada, and southern Idaho; in the Wyoming

Basin; and on the Colorado Plateaus and some

of the lower reaches of adjacent mountains.

This broad ecosystem occupies vast plains and

plateaus derived from lava flows, ancient lake

beds, and broad basins of alluvium. The more

individual plateau sections are usually delineated in terrace and tablelike fashion and range

33
F-41906B

Figure 20.—Sagebrush shrubs in the sagebrush ecosystem. In the area shown, herbaceous plants are lacking, having

been killed by overgrazing.

from rolling lava plains to maturely fringed and

dissected mesas. Elevations range roughly from

600 feet to 10,000 feet.

Climate.—The length of the frost-free season

normally is 120 days but is reduced to only 80

days at certain mountain sites. Annual precipitation is 5 to 12 inches—in some places almost

20 inches—40 to 50 percent of it coming in

the period December to March and only 25 to

40 percent occurring in the warmer half of the

year. Precipitation is only 20 percent of the

evaporation potential during the frost-free

season.

Vegetation.—The sagebrush ecosystem is

characterized by shrubs, principally of the

genus Artemisia, which are usually 1 to 7 feet

high. In some situations, other shrubs are part

of the vegetation. In other places, grasses such

as those of the genera Agropyron, Festuca, Poa,

and Bromus, as well as broad-leaved herbs, are

found in the understory.

Fauna.—Pronghorn, or antelope, use parts of

this ecosystem as rangeland throughout the

year, whereas mule deer prefer to use sagebrush rangeland only during the winter. The

Utah prairie dog is an endangered species of

this ecosystem. Other wild mammals that are

principal inhabitants of this ecosystem are the

Great Basin coyote, black-tailed jackrabbit,

pygmy cottontail, Ord's kangaroo rat, and

Great Basin kangaroo rat.

Bird populations are low during the breeding

season, averaging only about 25 pairs per 100

acres. The major influent birds include the

marsh hawk, red-tailed hawk, Swainson's hawk,

golden eagle, bald eagle. Cooper's hawk, prairie

falcon, burrowing owl, and long-eared owl. The

sage grouse and chukar are important game

birds. More than 50 additional species of birds

nest within the ecosystem.

Soils.—In the Columbia Plateaus province, the

sagebrush ecosystem occupies Mollisols having

black, friable, organic surface horizons and a

high content of bases. Inceptisols (Andepts) of

ashy nature are conspicuous in parts of the

Columbia Plateaus. In the Great Basin and

part of the Wyoming Basin, the soils of the

sagebrush ecosystem are Aridisols which have

pedogenic horizons, are low in content of

organic matter, have a clay horizon in some

places, and have accumulations of various salts

in some places. In part of the Colorado Plateaus

34
province, as well as part of the Wyoming Basin,

they are Entisols, which have no pedogenic

horizons. The remaining soils of the sagebrush

ecosystem in the Colorado Plateaus province

are Aridisols and Mollisols.

Land use.—-Most of the land within the sagebrush ecosystem is used for sheep and cattle

grazing, principally in the spring and fall.

Where sufficient water is available, irrigation

ranching and farming are practiced. The principal crops are hay, grain, potatoes, and beets.

Productivity Classes

Class 1.—Productivity class 1 represents the

best growing conditions in the sagebrush ecosystem. It includes the most productive sites of

Kiichler's sagebrush steppe and wheatgrassneedlegrass shrubsteppe communities. Dense to

scattered shrubs and dense to open grasslands

are characteristic of the class. Dominant species of the sagebrush steppe are big sagebrush,

bluebunch wheatgrass, and Idaho fescue. Other

important plants are balsamroot, Sandberg

bluegrass, and lupine. Dominant species of the

wheatgrass-needlegrass shrubsteppe are western wheatgrass, needle-and-thread, and plains

bluegrass. Herbage production varies from

1,500 to 2,000 pounds per acre. Forage

production ranges from 500 to 700 pounds per

acre.

Class 2.—Productivity class 2 of the sagebrush ecosystem includes the less productive

portions of the sagebrush steppe and wheatgrass-needlegrass shrubsteppe communities.

The physiognomy and dominant species are the

same as those of productivity class 1. Herbage

production ranges from 1,000 to 1,500 pounds

per acre. Forage production ranges from 300 to

500 pounds per acre.

Class S,'—Productivity class 3 includes the

more productive portion of Küchler's Great

Basin sagebrush community. Rainfall averages

nearly 10 inches per year. The class is characterized by dense to open brush, 1 to 3 feet in

height, with various mixtures of grass and

forbs. The dominant shrub is big sagebrush.

Some important associated plants are shadscale,

hopsage, ephedra, and milkvetch. Herbage production ranges from 500 to 1,000 pounds per

acre. Forage production varies from 100 to 200

pounds per acre.

Class 4.—Productivity class 4 encompasses

the area of least moisture in the sagebrush

ecosystem. Rainfall is less than 10 inches a

year, and evaporation is high. The physiognomy

is similar to that of class 1, except that the

brush is more scattered and of lower stature

in many places. Dominant species, in addition

to big sagebrush, are black sagebrush and low

sagebrush. Herbage production ranges from

0 to 500 pounds per acre. Forage production

ranges from 0 to 150 pounds per acre.

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows:

Productivity Pounds Productivity Pounds

class per acre class per acre

1 1,500-2,000 3 ... 500-1,000

2 1,000-1,500 4.. 0- 500

NO. 30.—THE DESERT SHRUB ECOSYSTEM

Physiography.—The desert shrub ecosystem

is a composite of various desert shrublands and

includes the salt flats of Great Salt Lake, the

southwestern desert plains and plateaus, the

western third of the Great Basin's mixture of

mountains and basins, the eastern edge of the

Great Basin, parts of Wyoming and Big Horn

Basins, and parts of the dissected Colorado

Plateaus.

Climate.—The normal length of the frost-free

season is 120 days in the more northerly parts

of the ecosystem and 200 days in the southwest.

Annual precipitation is only 5 to 10 inches.

In the western portion of the ecosystem where

the Pacific climate has an influence, 50 percent

or more of the meager precipitation occurs in

the winter, whereas in the more easterly portions which are under the influence of continental

or Rocky Mountain weather, only 15 to 25 percent of the precipitation occurs during the

winter. The amount of precipitation is only 20

percent of the evaporation potential during the

frost-free season.

VegetoMon,—The vegetation of the ecosystem

is characterized by xeric shrubs varying in

height from 4 inches to many feet. Stands are

generally open, with a large amount of bare

soil and desert pavement exposed. However,

some stands may be relatively dense. Understory vegetation is generally sparse. During

years of above-average rainfall, annuals may

be conspicuous for a short time.

Fauna.—There is a great diversity of habitats in the desert shrub ecosystem. Consequently, the species of the fauna are quite varied.

However, dominant animals are characteristically species of rats and pocket mice. In the

saltbush-greasewood community the pale kangaroo mouse and little pocket mouse are common. Animals associated with black sagebrush

are the desert wood rat and NuttalFs cottontail. The black-tailed jackrabbit is most numer35
ous in the greasewood sites. The cactus mouse

and desert kangaroo rat are abundant in the

saltbush desert. Merriam's kangaroo rat is

strongly associated with creosotebush. Other

important species in the ecosystem are the longtailed pocket mouse and antelope ground

squirrel.

Common larger mammals in the desert shrub

ecosystem are the desert kit fox, coyote, and

western spotted skunk. Desert mule deer and

peccary are associated with the paloverdecactus shrub community. Many desert birds are

very selective in their type of habitat. Greasewood may furnish a permanent residence for

the loggerhead shrike. Areas where tall cactus

is plentiful furnish homes for many birds,

including the Gila woodpecker, several species

of owl, and the purple martin. Gambel's quail,

the cactus wren, and the roadrunner are common in the southern part of the ecosystem.

Reptiles include numerous species of snakes

and lizards, including the Gila monster of the

tall cactus areas. The Sonoran pronghorn is

classed as an endangered species; few if any

of this species are left in southern Arizona.

The masked bobwhite quail is also an endangered species in this ecosystem.

Soils.—The soils of the desert shrub ecosystem include Aridisols (with pedogenic horizons) in the Great Basin and on southwestern

desert plains and plateaus, Entisols (with no

horizons), and Aridisols in the Wyoming Basin

and on the Colorado Plateaus. The soil of the

Great Salt Flats is unclassified.

Land use.—In the northern extension of this

ecosystem, livestock grazing is the principal

industry. Much of this grazing is done in the

winter. Where irrigation water is available,

ranching and farming are practiced. The principal crops are hay and small grains. In some

areas potatoes and sugar beets are grown.

In the Sonoran Basin and southern Arizona

and New Mexico, limited grazing is done at

favorable times. Irrigation farming is pracF-468718

FÍE:ure 21.—Shadscale and winterfat dominate this vegetation community of the desert shrub ecosystem.

36
ticed where water is available. Crops such as

cotton, citrus fruits, winter vegetables, and

alfalfa are grown.

Productivity Classes

Production in this ecosystem varies greatly

from year to year, depending on the moisture

supply.

Class 1.—Productivity class 1 includes Kiichler's mesquite bosques community, which has

a relatively high production potential. Better

sites in this community, those that are flooded

periodically, have produced nearly 1 ton of herbage per acre where the mesquite cover has

been reduced artifidally. Such production may

be indicative of the original potential of this

unit. The dominant plant species is mesquite.

Herbage production on the more frequently

flooded sites is between 750 and 1,000 pounds

per acre. Forage production is from 0 to 500

pounds per acre. A forest of low deciduous trees

is characteristic.

Class 2,—This class includes the more moist

sites of the saltbush-greasewood community.

Greasewood, saltgrass, and pickleweed are

dominant and associated species. Herbage production varies from 500 to 750 pounds per acre.

Forage production ranges from 50 to 200

pounds per acre. Low to medium brush and succulent forbs are characteristic—with or without grass.

Class 3,—The more productive sites of two

major plant communities, blackbrush and saltbush-greasewood, are included in this productivity class. Average sites of the mesquite

bosques community are also included. Blackbrush is the dominant species of the blackbrush

unit. Shadscale, greasewood, and saltbush are

dominants in the saltbush-greasewood unit.

Other important species in this community are

saltgrass, winterfat, and bud sagebrush.

Class 4.—This productivity class is associated with the drier and hotter portions of the

desert shrub ecosystem. Three communities,

creosotebush, creosotebush-bursage, and paloverde-cactus shrub, are included in this class.

Bursage is dominant in the creosotebush unit,

while creosotebush and white bursage are dominant in the creosotebush-bursage unit. The

paloverde-cactus shrub community is characterized by paloverde, pricklypear, cholla, saguaro,

and bursage. The stands of low to mediumtall shrubs are characteristically quite open.

Herbage production ranges from 40 to 100

pounds per acre in the creosotebush and creosotebush-bursage units and from 100 to 250

pounds in the paloverde-cactus shrub unit.

About 30 to 40 percent of the herbage can be

considered to be forage.

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows:

Productivity Pounds Productivity Pounds

class per acre class per acre

1 750-1,000 3. 250- 500

2 ...- 500- 760 4 ._ 40- 250

NO. 31.—THE SHINNERY ECOSYSTEM

Physiography,—The shinnery ecosystem covers considerable areas of sand hills and river

dunes across the southern Great Plains, the

major portion occurring along the Canadian

River. The ecosystem is estimated to occupy

about 6 million acres. The valley of the

Canadian River is estimated to be 1,000 feet

below the surrounding areas, is cut deep into

red sandstone, and is 5 to 20 miles wide. Terraces, mesas, cliffs, and side canyons characterize the landscape. Water, when the river is

low, disappears and reappears through sand

beds.

Climate.—The shinnery ecosystem is rather

small geographically; thus, the climate is relatively uniform throughout the area. The frostfree season lasts 180-200 days. Precipitation

ranges from about 15 inches in New Mexico to

25 in Oklahoma. Two-thirds to three-fourths of

the precipitation falls in the warmest months ;

the amount of precipitation in winter is low.

The potential evaporation is several times the

precipitation. During the warmest months, precipitation is a quarter of the potential evaporation in the western part of the ecosystem and

one-half in the eastern part.

Vegetation,—The vegetation of the shinnery

ecosystem is a midgrass prairie with open to

dense stands of broad-leaved deciduous shrubs

and occasional needle-leaved low trees and

shrubs. The major shrubs are Havard oak and

mesquite. Little bluestem and side-oats grama

are the most common grass species. Sand bluestem is sometimes locally common. Sand sagebrush and yucca are the most common low

shrubs.

Fauna.—The fauna of the shinnery ecosystem

is a mixture of species common in the surrounding plains grasslands, pinyon-juniper, and

southwestern shrubsteppe ecosystems, forestedge species also being present along the river

bottoms.

Soils.—The soils of most of the shinnery

ecosystem are Mollisols. In the extreme western

portion are Aridisols. Alfisols are in two small

areas. The "island" of shinnery far to the south

87
Figure 22.—Grassland in the shinnery ecosystem; scattered stands of oak in rear.

SCS-TE-910-B

of the rest of the ecosystem is on Alfisols. In

some places the soils are Entisols.

Land use.—Where shrubs are not too dense,

livestock grazing is common.

Productivity Classes

Class 1.—The most productive areas of this

ecosystem yield an average of 2,000 pounds of

herbage per acre. These areas have a high proportion of tall-grass species, such as big bluestem and sand bluestem, together vs^ith midgrasses, such as side-oats grama and little bluestem. The soils are mainly Mollisols (Calciustolls

plus Haplustolls) which are medium to high in

content of bases and are moist during part of

the growing season but dry for extended periods. Most of the level areas are dry-farmed or

irrigated. Wind erosion makes continuous use

of cover crops necessary. The trend is toward

hay production.

Class 2.—Herbage yields average 1,500

pounds per acre in this productivity class. The

major species are little bluestem and side-oats

grama. There are scattered stands of big bluestem and sand bluestem. The shrub species

characteristic of this ecosystem occur in small,

dense patches. The soils are mainly Alfisols

(Haplustalfs). Areas in productivity class 2

are used as native rangeland or are farmed if

conditions permit.

Class 3.—The vegetation characterizing this

productivity class is a mixture of midgrasses

and short grasses occurring on or near the outer

edge of valleys and on the valley walls. Class 3

areas receive runoff when it occurs, but are dry

for long periods. Herbage yields average 1,000

pounds per acre. The major grasses are threeawns, gramas, and, in scattered areas, western

wheatgrass. Shrubs, such as Havard oak and

sumacs, occur more commonly here than elsewhere in the ecosystem. Mesquite occurs as

scattered low trees. The soils are mainly

Aridisols (Haplargids, gently to moderately

sloping). Class 3 areas are used as native

rangeland.

Class Jt.—This productivity class is represented by vegetation occurring on the more

sandy areas (stabilized sand dunes). Herbage

yields average 500 pounds per acre. Sand bluestem and little bluestem are the major grass

species. Other species are big sandreed, giant

and sand dropseed, and hairy and side-oats

grama. Yucca and sand sagebrush are the two

most important low shrubs. The soils are mainly

Entisols (Ustipsamments, moderately sloping)

characterized by fine sand. Class 4 areas are

still in native grasses and forbs.

38
NO. 32.—THE TEXAS SAVANNA ECOSYSTEM

Physiography.—The Texas savanna ecosystem occupies the western end of the West

Gulf Coastal Plain and the southern part of the

Great Plains. It is commonly referred to as the

Rio Grande Plains of south Texas and the

Edwards Plateau of south-central Texas. The

Rio Grande Plains is alluvial and is possibly a

deltaic plain of the Rio Grande. It is a relatively

flat plain, about 400-600 feet above sea level,

that rises 1,000 feet rather abruptly to the

Edwards Plateau. The Edwards Plateau itself

reaches an elevation of 3,600 feet at its western

end. Its edges are maturely dissected by

streams. The surface in its interior is a flatland

traversed by dry valleys or "draws".

Climate.—In this ecosystem the frost-free

season ranges from about 250 to well over 300

days. Precipitation ranges from 20 to 30 inches

annually, more than half of which falls in the

warmest months and less than a quarter in the

period December to March. Annual evaporation

is 70-80 inches; during the period May to

October, the potential evaporation is about

twice the precipitation.

Vegetation.—This is a high-shrub savanna

ecosystem with a dense to very open synusia of

broad-leaved, deciduous and evergreen, low

trees and shrubs and needle-leaved, evergreen,

low trees and shrubs. The grass varies from

short to medium tall, and the herbaceous vegetation varies from dense to open. Mesquite is

the most widespread woody plant. Others are

Acacia spp., oaks, juniper, and ceniza along the

Rio Grande valley and bluffs. Opuntia spp. are

ifk^t^- ••sr "K

'i-'fS

i-iñrftJ

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Fignire 23.—Herefords in an open stand of low trees and shrubs and short and medium-tall grasses in the Texas

savanna ecosystem.

39
widespread. The herbaceous plants are mainly

bluestems, three-awns, buffalo grass, gramas,

and curly mesquite and tobosa on the Edwards

Plateau.

Famia,—The Texas savanna ecosystem is

noted for the abundance of white-tailed deer

and wild turkeys. The collared peccary is common in some areas along the Rio Grande, where

several species of Mexican or tropical distribution make their only entry into the United

States. Examples; are the chachalaca and the

coatimundi. The armadillo is present. The fox

squirrel is hunted in wooded areas along

streams. Among the fur bearers are the ringtail and the raccoon.

Great numbers of white-winged doves once

nested in brushy areas along the southern Rio

Grande, but clearing of land for agricultural

purposes has contributed to reducing their

population. The golden-cheeked warbler is a

rare species. The mourning dove, scaled quail,

and bobwhite are game birds in the ecosystem.

A number of hawks and owls are present.

Soils,—Soils in the Texas savanna ecosystem

are varied, but the different soil orders are

unusually well correlated with the different

plant communities within the ecosystem. The

mesquite-live oak savanna, for example, is on

the only Entisols within the ecosystem. The

soils of the juniper-oak savanna are almost

entirely Mollisols, while an ''island'' of Alfisols

within the area of Mollisols corresponds with

the boundaries of the mesquite-oak savanna. In

the mesquite-acacia savanna, Mollisols, Alfisols,

and Vertisols occur.

Land i/se.—-Land which is not cropped and

on which the brush is not too dense is grazed

by livestock.

Productivity Classes

Class 1.—The mesquite-live oak savanna

community on the West Gulf Coastal Plain

characterizes this productivity class. Herbage

yields average 2,600 pounds per acre. Annual

precipitation averages 29 inches but fluctuates

greatly, and droughts are common. Consequently, the yield of herbage also fluctuates

greatly. Major components of the overstory are

live oak, shin oak, and mesquite. Major grasses

are seacoast bluestem, Texas wintergrass, curly

mesquite, and three-awns. Forbs are important

and often make up about 25 percent of the

herbage production. The soils are Entisols

(Ustipsamments) that are moderately sloping.

These are loamy sands and are intermittently

dry for long periods. About four-fifths of the

vegetation community remains as rangeland of

native shrubs and grasses. The remainder is

irrigated or dry-farmed.

Class f.—Although this class contains a number of vegetation communities, the mesquiteacacia savanna on the West Gulf Coastal Plain

represents the class. This savanna is a denseto-open grassland with broad-leaved, deciduous,

low trees and shrubs. Acacia spp. are the most

common shrubs, and mesquite is scattered

throughout the community. The major grasses

are seacoast bluestem, plains bristlegrass, and

buffalo grass. Herbage production averages

2,100 pounds per acre, of which about 35 percent is forbs. The most abundant forbs are one=

seed crotón, horse mint, and prairieconeflower.

The soils of productivity class 2 are Mollisols (Haplustolls plus Argiustolls, gently sloping, and Calciustolls, shallow and gently

sloping), Alfisols (Haplustalfs plus Haplustolls

and Calciustolls, shallow and gently sloping),

and Vertisols (Pellusterts plus Chromusterts,

gently sloping). All these soils have similar

characteristic subsurface horizons high in content of bases, are mostly shallow, and are intermittently dry for long periods during the warmest months. Most of this area remains in ranges

of native shrubs and grasses, which are grazed

by beef cattle. About 10 percent of the area,

mainly along the Rio Grande and the Nueces

River, is irrigated.

Class ^.—The mesquite-oak savanna and the

juniper-oak savanna on the Edwards Plateau

are vegetation communities in this productivity

class. In the areas of these savannas, herbage

production averages up to 1,500 pounds per

acre. Mesquite and oak dominate the open

synusia of broad-leaved deciduous trees of the

mesquite-oak savanna. Ashe juniper and live

oak dominate the open synusia of trees of the

juniper-oak savanna. The herbaceousv dominants of both savannas are little bluestem, curly

mesquite, tobosa, and buft^alo grass. Pricklypear

occurs here and there throughout the plateau

area. Forbs are of lesser importance.

The soils are Mollisols (Haplustolls, shallow,

extending 20 inches to bedrock, plus Pellusterts,

gently to moderately sloping) in the mesquiteoak savanna and Alfisols (Haplustalfs plus

Argiustolls, gently to moderately sloping) in

the juniper-oak savanna. The juniper-oak

savanna occurs on the deeper soils that have a

thin subsurface horizon of accumulated clay,

while the mesquite-oak savanna occurs on shallow soils that have subsurface horizons in which

salts or carbonates have accumulated. More

than four-fifths of the area of these two savannas is in rangeland or shrubs and grasses used

by cattle, sheep, and goats. The remainder is

used for dry farming. Deer habitats in the area

are managed for economic returns.

Class 4.—The ceniza shrub vegetation community of productivity class 4 is characterized

by open to dense stands of broad-leaved, deciduous and evergreen shrubs and a patchy synusia

of grass. It is located along the lower Rio

40
Grande valley and bluffs. The dominant vegetation consists of creosotebush, ceniza, and

mesquite, underlain with patches of gramas,

curly mesquite, sacaton, Arizona cottontop, and

three-awns. Pricklypear is common. Herbage

production sometimes averages as much as

1,600 pounds per acre but is usually much less.

The soils of this vegetation community are

Vertisols (Pellusterts plus Camborthids and

Torrerts, gently sloping) which are clayey soils

that, when dry, have wide, deep cracks that

remain open intermittently for periods totaling

more than 3 months. This area can be very

productive when there is adequate precipitation. Most of the floor of the Rio Grande valley,

in which approximately 50 percent of the ceniza

shrub community is located, is irrigated. The

remainder of the unit is on valley slopes and

bluffs which are still in native shrub and grass

species. Conversion of brush areas to agricultural use has resulted in a drastic reduction in

the nesting habitat of the white-winged dove

in the United States.

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows:

Productivity Pounds Productivity Pounds

class per acre class per acre

1 2,250-3,000 3 .- 750-1,500

2 1,500-2,250 4 0- 750

NO. 33.—THE SOUTHWESTERN SHRUBSTEPPE ECOSYSTEM

Physiography.—The southwestern shrubsteppe ecosystem occurs south of the Rocky

Mountains. It occurs as relatively large blocks

of almost-level desert plains isolated between

roughly parallel low mountain ranges of the

Sonoran Desert, Mexican Highland, and Sacramento section, through southern Arizona, New

Mexico, and Texas. This ecosystem occurs at a

lower altitude than the pinyon-juniper ecosystem and is often referred to as the semidesert

grass-shrub type.

Climate.—Temperatures in this ecosystem

•".fí«*«Á^w SiÁiiCuM'ii^^^ Mi.*»«*»-. i-«^WÄi?i

F-477B69

Pig:ure 24.—Areas of short gn^ass and scattered shrubs and of shrubs with scattered patches of short grass are

characteristic of the southwestern shrubsteppe ecosystem.

41
are not as variable as in ecosystems covering

larger geographic areas. The frost-free season

ranges from slightly less than 180 days in Arizona to more than 240 days at the southeastern

boundary, in Texas. Precipitation, half of which

normally falls in the warmest months, varies

from 10 inches in the west to about 18 inches

at the eastern boundary of the ecosystem.

Potential evaporation is high, being 80-90

inches annually. During the warmest months it

is 4 to 10 times the precipitation.

Vegetation,—-The southwestern shrubsteppe

ecosystem is characterized by vegetation types

ranging from short grass with scattered shrubs

to shrubs with scattered areas of short grasses.

Yucca is one of the most characteristic woody

plants in the ecosystem. Mesquite is abundant

in many areas. Creosotebush and tarbush are

dominant among the shrubs. Black grama,

three-awns, and tobosa dominate the herbs.

Side-oats grama and curly mesquite are also

important. The shrub-grass stands occupy shallow soils with no development or little development. The grass-shrub stands occupy the soils

with more development.

Fauna,—BecanBe of the geographic proximity of the two ecosystems, the fauna of the

southwestern shrubsteppe ecosystem is similar

to that of the desert grasslands ecosystem.

Pronghorn, or antelope, and mule deer are the

most widely distributed large game animals.

The common white-tailed deer occurs in the

eastern portion of the ecosystem, in Texas. The

collared peccary or javelina is common in the

southern part of the ecosystem. The whitewinged dove is locally important in Arizona, as

is the more widespread mourning dove. The

scaled quail and Gambel's quail are present in

most of the area, and the bobwhite reaches the

eastern portion of the ecosystem. The blacktailed jackrabbit, desert cottontail, kangaroo

rat, wood rats, and numerous smaller rodents

compete with domestic and wild herbivores for

available forage and are preyed upon by the

coyote, bobcat, golden eagle, great horned owl,

red-tailed hawk, and ferruginous hawk.

Soils,—In the western portion of this ecosystem, the soils are primarily Aridisols. Some

are Moílisols. The eastern portions, the TransPecos shrub savanna, are mainly on Aridisols in

the north and Entisols in the south. Junipers

occur entirely in the areas of Entisols, according to Küchler.

Land use.—The areas in this ecosystem are

used as rangeland except where they have been

converted to irrigation farming or other uses.

Productivity Classes

Class 1 .—The grama-tobosa shrubsteppe

community that has a low shrub population of

creosotebush and yucca characterizes this productivity class. Herbage production averages

500 pounds per acre, ranging from 450 to 600

pounds. Black grama and tobosa occur most

commonly. The soils are mainly gently sloping

Aridisols that have a loamy horizon of accumulated clay and, usually, a horizon containing

large amounts of calcium carbonate or gypsum.

The Trans-Pecos shrub savanna, where junipers commonly occur, also characterizes this

productivity class. This community occupies the

Stockton Plateau, which is the southwestern

portion of the Edwards Plateau. It is in a belt

of higher rainfall and at a higher altitude than

the grama-tobosa shrubsteppe. The major grass

species of this community are tobosa, curly

mesquite, and buffalo grass. Forbs are of lesser

importance. Soils are mainly gently to moderately sloping Entisols, which are clayey, have a

regular decrease in organic-matter content with

depth, have a gravelly or stony surface in this

area, and are usually less than 2 feet deep above

caliche. Four-fifths of this vegetation community remains as rangeland. The remainder is

under irrigation or in nonfarm uses.

Class 2,—The Trans-Pecos shrub savanna

characterizes this productivity class. Herbage

yields average 300 pounds per acre. Shrubs

such as tarbush and creosotebush are common.

Short grasses such as tobosa, chinograss, and

bush muhley are present. Forbs are few\ The

shrubs and dwarf shrubs occur as stands that

are dense or scattered ; consequently, herbage

production varies. The soils are mainly gently

sloping Aridisols (Calciorthids) that are shallow and have a horizon in which large amounts

of calcium carbonate or gypsum have accumulated. The area of productivity class 2 is used

mainly as rangeland.

Class o .—This class is represented by the

grama-tobosa shrubsteppe community. There is

a relatively common occurrence of Joshua-tree

yucca and other species of yucca, as well as a

grass synusia varying from open to dense. Black

grama and tobosa are the major species in the

grass synusia. Herbage production varies from

150 to 300 pounds per acre and averages

approximately 200 pounds. This vegetative community occupies a smair area in western Arizona, The soils are Aridisols (Durargids) that

have a hardpan cemented with silica and Entisols (Torriorthents) that extend less than 20

inches to bedrock. This area is used as

rangeland.

Class 4,-—^0 one type of vegetation characterizes this productivity class. The class is characterized by areas tending toward the desert

shrub ecosystem; in these areas shrub vegetation is more prevalent, and herbage production

averages 100 pounds per acre. Major shrubs are

42
creosotebush, tarbush, Joshua-tree yucca, and

juniper. Major grasses are tobosa and gramas.

The soils are mainly gently to moderately sloping and have a stony surface. They are Aridisols (Durargids) that have a hardpan and Entisols (Torriorthents) that extend less than 20

inches to bedrock. Class 4 areas are used as

rangeland.

HERBAGE PRODUCTION

A summary of herbage production in the ecosystem follows:

Pounds Productivity Pounds

per acre class per acre

1 450-600 3- .__.- 150-300

2 300-450 4 _ 0-150

Productivity

class

NO. 34.—THE CHAPARRAL-MOUNTAIN SHRUB ECOSYSTEM

Physiography.—The chaparral-mountain

shrub ecosystem occupies mountain areas over

3,000 feet high in northern California and

southern Oregon, areas ranging from sea level

to low mountains (up to 8,000 feet high) in the

southern part of the California Coast Ranges,

mountains over 3,000 feet high in the Middle

Rocky Mountains, low mountains in the Gila

Mountains, and low and high tablelands in the

southern part of the Great Basin.

Climate.—The length of the frost-free season

in much of the California portion is 160 to 200

days, depending on latitude and elevation. However, one area along the southern coast has a

frost-free season of 300 days. In the Middle

Rocky Mountains, the frost-free period is 80 to

120 days, depending on elevation. The Gila

Mountains have a frost-free period of 160 to

180 days. In the southern part of the Basin and

Range province the frost-free season lasts 200

days. Annual precipitation varies from 10 to 28

inches, sometimes more. The California area

receives only 10 to 25 percent of its precipitation in the warmest months. The northern part

of the Great Basin and the part of the ecosystem in the Middle Rocky Mountains get 40 to 50

percent of their precipitation in the warmest

months. The Gila Mountains and the southern

part of the Basin and Range province receive

50 to 66 percent of their annual precipitation in

the warmest months.

Year-round mild temperatures in much of the

California portion of the ecosystem tend to offset some of the disadvantages of lack of rain in

summer. Furthermore, coastal areas receive

some moisture from fog in summer. The precipitation is normally only 20 percent of the

evaporation potential in the Middle Rocky

Mountains, the Gila Mountains, and the southern Basin and Range province. In California

the precipitation is 20 to 40 percent of the

evaporation potential.

Vegetation,—The vegetation of the ecosystem

consists of dense to open brush or low trees.

Deciduous, semideciduous, and evergreen species are represented. Some of the brush types

are so dense that understory vegetation is practically eliminated, while other types support a

highly productive understory. Recent activities

of man have altered the types of vegetation to

such a degree that reconstruction of their original state would be difficult.

Fauna.'—The fauna is quite diverse from

north to south in the chaparral-mountain shrub

ecosystem; however, some species are quite

widespread. Mule deer throughout the ecosystem and white-tailed deer in the south are the

most important large mammals. Other large

mammals, such as the coyote, mountain lion,

bobcat, black-tailed jackrabbit, ringtail, striped

skunk, and spotted skunk, are widespread in

the ecosystem. Some important species, such as

the javelina and the band-tailed pigeon, are

found only in the southern part of the ecosystem. The wood rat is one of the most characteristic animals of the ecosystem. Other small

marnmals include ground squirrels and mice.

Birds are very numerous in the brush types

of the ecosystem throughout the year. More

than a hundred species were identified in the

scrub oak type in Utah. Over 40 resident birds

were noted in the oak-juniper community.

Among the birds in the oak-juniper areas are

the golden-fronted woodpecker, turkey, and bobwhite. Reptile species are quite numerous in the

southern portion of the ecosystem. Two rare

and endangered species are found in the ecosystem, both in the chaparral community. One

of them, the California condor, has its range

partially within the community. The other is

the San Joaquin kit fox. A third endangered

species, the masked bobwhite, has been extirpated from the United States portion of the

ecosystem.

Soils.—In the northern part of California,

the chaparral-mountain shrub ecosystem occupies Ultisols which are low in content of bases

and have subsurface horizons of clay and weatherable minerals. The remainder of the California portion of the ecosystem in the Coast

Ranges occupies Mollisols which are on steep

slopes, are high in content of bases, and lack

accumulations of clay; Alfisols which have

accumulations of clay and sometimes have a

carbonate-cemented horizon; and Entisols

which have no horizons, are low in content of

43
Figure 25.-

F-622877

-Areas of brush and low trees are characteristic of the chaparral-mountain shrub ecosystem.

organic matter, and are less than 20 inches deep

in some places. In the Rocky Mountains, this

ecosystem occupies Mollisols that have a subsurface horizon of clay. In the southern edge of

the Basin and Range province and the upper

Gila Mountains, the ecosystem mainly occupies

Aridisols that have a low content of organic

matter and a loamy horizon of accumulated

clay.

Land use.—Large portions of the California

areas of the ecosystem have been converted to

grass range for livestock and for firebreaks.

Production of range livestock is the principal

enterprise in these places. The vegetation serves

as cover to retard erosion and protect watersheds, thus benefitting croplands, high-value

developments, and urban areas below. Grassed

fuel breaks to retard spread of fires and the

required grazing treatment of them are striking

and may become more common. The conversion of the shrubland has also increased deer

habitats.

The interior and southwestern portions of

the ecosystem are largely used for livestock

grazing. Lands in these places that are suitable

for cropping and irrigation are most often used

for production of forage crops.

Productivity Classes

Class 1.—Productivity class 1 includes the

northern two-thirds of the chaparral community in California and southern Oregon and the

more productive part of the mountain-mahogany-oak scrub community. Precipitation in class

1 areas is as high as anywhere in the ecosystem.

Where a site is not fully occupied by thick

brush, high yields of herbaceous vegetation are

common.

Dominant plants of the chaparral community

44
are chamise, species of manzanita, and species

of California-lilac. Chamise may form a dense,

impenetrable cover in places. Gambel oak is

dominant in this productivity class of the ecosystem but may be associated with substantial

amounts of other species. Herbage production

in the productivity class is 1,500-2,000 pounds

per acre. Forage production may be as high as

900 pounds per acre, or it may be less than 100

pounds, depending on the thickness and species

of the brush.

Class 2,—This productivity class includes

moderately productive sites of the mountainmahogany-oak scrub and the oak-juniper v^oodland communities and the transition between

the two. Gambel oak and other deciduous shrubs

are dominant in the northern areas but give

way to evergreen species in the southern areas.

The dominant species of the oak-juniper woodland are alligator juniper, one-seed juniper,

Emory oak, and Mexican blue oak. Blue and sideoats grama, as well as numerous brush species,

are associated with this community. Herbage

production in the productivity class is 1,000 to

1,500 pounds per acre. Forage production,

depending on the thickness of the brush and

species composition, varies from 100 to 700

pounds per acre.

Class B,—Productivity class 3 encompasses

the less productive areas of the chaparral community, including the part in southern California. The mountain-mahogany phase of the

mountain-mahogany-oak scrub community is

also included. Dominant plants in the chaparral

areas are chamise, manzanita, and Californialilac. The dominant species of the mountainmahogany phase is mountain-mahogaiiy. Herbage production ranges from 500 to 1,000 pounds

per acre. Forage production varies from 50 to

300 pounds per acre.

Class Í,—The coastal sagebrush community

is included in this productivity class. It is characterized by low-growing brush (generally 1 to

2 feet high). Dominant species are California

buckwheat, white sage, and black sage. Herbage

production in this class is from 0 to 500 pounds

per acre. Forage production is from 0 to 100

pounds per acre.

HERBAGE PRODUCTION

A summary of herbage production in the ecosystem follows:

Productivity Pounds Productivity Pounds

class per acre class per acre

1 1,500-2,000 3 500-1,000

2 1,000-1,500 4: 0- 500

NO. 3 5.—THE PINYON-JUNIPER ECOSYSTEM

Physiography.—The pinyon-juniper ecosystem occupies portions of the Basin and Range

province (Utah, Nevada, southern Idaho, and

southeast Oregon) with its intermingled basins

and mountains and also occupies many of the

Colorado Plateaus, where it is often adjacent

to sagebrush sites. Juniper usually occupies

rockier and rougher terrain than sagebrush.

Where sagebrush is common on the plains, terraces, and gentle portions of plateaus, the

pinyon-juniper ecosystem tends to occupy the

adjacent contiguous sites of eroded and rough

dissections.

Climate,—-The normal length of the frostfree season is 120 days. Annual precipitation is

10 inches, 40-50 percent of which occurs during the warmest months in the Great Basin,

whereas 50-66 percent occurs during the warmest months in the Colorado Plateaus.

Precipitation is normally only 20 percent of the

evaporation potential during the frost-free

season.

Vegetation,—The name "pygmy forest" characterizes the pinyon pine and juniper woodlands of this ecosystem. The trees occur as

dense to open woodland and savanna woodland.

They may grow to a height of 30 feet but are

generally less than 15 feet tall. They are bushy,

being almost as wide as they are tall.

Herbage production is determined to a large

extent by the amount of tree canopy. However,

soil factors that affect the moisture supply also

affect the production of herbage. These factors

are texture, development of the B horizon, depth

of solum, stoniness, and nature of the substrata.

Slope or aspect is also a factor.

Fauna,—The major mammalian influents in

the pinyon-juniper ecosystem are the mule

deer, mountain lion, coyote, and bobcat. Elk are

locally important. The less important influents

include the wood rat, white-footed mouse, cliff

chipmunk, jackrabbit, cottontail, rock squirrel,

porcupine, and gray fox. The ring-tailed cat

and spotted skunk occur rarely.

The most abundant resident birds in the pinyon-juniper ecosystem are the gray titmouse,

Woodhouse's jay, western red-tailed hawk,

golden eagle, red-shafted flicker, pinyon jay,

lead-colored bushtit, and rock wren. Summer

residents include the western chipping sparrow,

night hawk, black-throated gray warbler,

northern cliff swallow, western lark sparrow,

Rocky Mountain grosbeak, desert sparrow, and

western mourning dove. The common winter

residents are the pink-sided junco, Shufeldt's

junco, gray-headed junco, red-backed junco.

45
Figure 26.—"Pygmy forests" are characteristic of the pinyon-juniper ecosystem.

r-522878

Rocky Mountain nuthatch, mountain bluebird,

western robin, and long-crested jay. Turkeys

are locally abundant during the winter.

Among the reptiles are the horned lizard,

sagebrush swift, collared lizard, and Great

Basin rattlesnake.

Soils.—In the Basin and Range province, the

pinyon-juniper ecosystem occupies Aridisols

which have pedogenic horizons, are moderate

to low in content of organic matter, and may

have accumulations of carbonates. In the Colorado Plateaus the woodland occupies Aridisols,

Entisols which have no pedogenic horizons, and

Mollisols which have an organic surface horizon and a high content of bases.

Land use.—The pinyon-juniper ecosystem is

used principally for grazing and yields a limited

amount of timber products, mainly pinyon

Christmas trees, pine nuts, and juniper fence

posts.

Productivity Classes

Class 1.—Productivity class 1 is associated

with open or savanna woodlands, the deeper

(depths of 12 inches or more), better developed

soils, and northerly aspects, where moisture

conditions are most favorable to plant growth.

Dominant species are one-seed juniper, Utah

juniper, pinyon pine, singleleaf pinyon, and

western juniper. Important understory species

are big sagebrush, western wheatgrass, bluebunch wheatgrass, blue grama, cliffrose, bitterbrush, and Indian ricegrass. Herbage production varies from 600 to 800 pounds per acre.

Forage production is from 200 to 300 pounds

per acre.

Class 2.—Productivity class 2 occurs on sites

of fairly open woodlands and on soils comparable to those of productivity class 1. The dominants and understory species are the same as

46
those of productivity class 1. Herbage production varies from 400 to 600 pounds per acre.

Forage production is from 150 to 200 pounds.

Class S,—Productivity class 3 occurs on sites

with a moderate cover of woodland or on soils

with lower water-holding capacity than those

of the two higher productivity classes. The

dominant species remain the same, but the

shrubs may be sparse or suppressed. Associated

grasses are thinned out to some extent. Herbage production is from 200 to 400 pounds per

acre. Forage production is from 75 to 150

pounds per acre.

Class 4.—Productivity class 4 occurs on sites

where the woodland cover is heavy; the crown

canopy may cover 50 percent or more of the

land. The class also occurs on the drier soils.

Dominants are the same as those in the other

three classes, but the understory is sparse and

may consist almost entirely of scattered cryptantha and pricklypear. Herbage production is

from 0 to 200 pounds per acre. Forage production is from 0 to 75 pounds per acre.

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows :

Productivity Pounds Productivity Pounds

class per acre class per acre

1 600-800 3 200-400

2 - 400-600 4 ...... 0-200

NO. 36.—THE MOUNTAIN GRASSLANDS ECOSYSTEM

Physiography.—The mountain grasslands

ecosystem of the western Mountain States consists mainly of open, untimbered areas, yet it is

often adjacent to or surrounded by ponderosa

pine, Douglas-fir, or lodgepole pine at moderate

elevations. At high elevations the ecosystem is

subalpine and is on mountain slopes or faces

adjacent to spruce-fir forests and patches of

alpine fir or whitebark pine. It also occupies

some of the best drained soils of valleylike

areas intermingled with mountains, and it occupies various foothills, tablelands, and low

mountains. The higher mountain settings can

be rich with streams and lakes. These beautiful

pastoral openings and exposures commonly provide unobstructed mountain vistas which are not

observable from mountain terrain completely

cloaked in forest.

Climate.—The normal length of the frost-free

season in most of the mountain grasslands ecosystem is 120 days. However, in the mountain

valleys of the Northern Rocky Mountains, it is

less than 120 days, being only 80 days or less at

high elevations. Annual precipitation in much

of the ecosystem is 20 inches, and in the high

mountains it is 30 inches or more. Sixty-six to

75 percent of the precipitation falls during the

warmest months in central Colorado and east

of the Continental Divide in Montana. In the

Northern Rocky Mountain grasslands west of

the Divide, 50 to 66 percent comes during the

warmest months, and in the Palouse hills of the

Northwest, only 25 to 40 percent comes during

this period. Annual precipitation is 30 to 35 percent of the evaporation potential.

Vegetation.—Although the mountain grasslands ecosystem ranges from foothills at northerly latitudes to high mountain sites, it is

characterized throughout by bunchgrasses of

the fescue and wheatgrass groups. An abundance of desirable forbs appears to increase the

productivity of some of the higher sites.

Fauna.—In the foothills portion of the mountain grasslands ecosystem, pronghorn, or antelope, are resident and mule deer are winter

visitors. Where there is an interface with the

sagebrush ecosystem, common animals are the

black-tailed jackrabbit, pygmy cottontail, and

various mice. At low to medium elevations,

various subspecies of ground squirrels are present, as well as the badger. At medium to high

elevations, the grasslands seasonally support

Rocky Mountain elk and mule deer. The pocket

gopher is well distributed throughout the ecosystem. Predators which are well distributed at

high elevations are the bobcat, black bear, and

coyote. Two of the more common birds present

are the robin and horned lark. Marsh hawks,

sparrow hawks, and golden eagles are common

raptors.

Soils.—In central Colorado the ecosystem

occupies Aridisols and Mollisols with developed

horizons. In the Yellowstone River area of

south-central Montana, the grassland soils are

Entisols with no horizon development. In the

grasslands of the Northern Rocky Mountains,

the soils are Alfisols and Mollisols. Mollisols are

also the major soils of the Columbia Plateau's

foothills or Palouse hills. Much of the central

and eastern portion of rolling hill land is locally

termed part of the Palouse Prairie and has

wind-laid soil of great depth.

Land use.—^^Much of the ecosystem at lower

elevations or on foothills was plowed soon after

settlement for production of small grains, most

notably the Palouse Prairie hills of north

central Oregon and the extreme eastern portion

of Washington and adjacent parts of Idaho.

Unbroken portions of the foothill grasslands

on steep slopes and in canyons are used as

spring-fall range for livestock and as winter

range for big game. These areas are a partic47
;f-'*^J^^'

,r¿ ^ K

•fs---'.,

F-502B79

Figure 27.—This open rangeland of fescue and wheatgrass, next to timbered areas, is representative of the mountain

grasslands ecosystem.

ularly critical resource in big-game management. At moderate elevations the mountain

grasslands are sites of livestock ranches in some

places. At higher elevation, as in Colorado,

Wyoming, and Montana, the grasslands are

important summer ranges for big game and

cattle, prime watersheds and recreation areas,

and the traditional mountain settings of sheep

and shepherds.

Productivity Classes

The productivity classes for this ecosystem

are related to total precipitation, the abundance

of precipitation during the growing season, and

soil factors.

Class 1.—This productivity class is commonly

associated with high-elevation lands of subalpine character, or nearly so, where 66 to 75

percent of the precipitation falls in the growing

season. There are many grasses, including Idaho

fescue and five species of wheatgrass. Forbs

may make up 35 percent or more of the cover.

Herbage production varies from about 2,250

pounds to 3,000 pounds per acre.

Class 2.—This class occupies areas that are

at moderate to high elevations and reach subalpine conditions. Desirable forbs constitute 10

to 35 percent of the vegetation in some places.

Several fescues are prominent. Associated

grasses are of the genera Muhlenbergia, Stipa,

Danthonia, and Agropyron. Herbage production

varies from 1,500 to 2,250 pounds per acre.

Class 3.—This class occupies low mountains

and higher foothills in areas where not more

than 40 percent of the precipitation comes in

the growing season. Its dominant grasses are

Idaho fescue and bluebunch wheatgrass. The

larg:e forbs of the genera Balsamorhiza and

Helianthella are conspicuous. Herbage production varies from 750 to 1,500 pounds per acre.

Class 4-—Productivity class 4 occupies foothills at northerly latitudes and, at its lower

edge, is bordered and invaded by big sagebrush.

Bluebunch wheatgrass is the dominant plant.

There are about 300 to 500 bunches of it per

100 square meters. The spaces in between are

sparsely to fairly well covered with Sandberg

bluegrass and small forbs, mostly annuals.

Herbage production varies from 0 to 750

pounds per acre.

HERBAGE PRODUCTION

A summary of herbage production in the ecosystem follows:

Productivity

class

Pounds

per acre

1 2,250-3,000

2 1,500-2,250

Productivity Pounds

class per acre

3 750-1,500

4 0- 750

48
NO. 37.—THE MOUNTAIN MEADOWS ECOSYSTEM

Psysiography.—The mountain meadows ecosystem consists of wet to intermittently wet

sites in the forest zone of mountains in the

Western States. Typically it occurs on almost

flat to gently sloping topography, as in valleys

and basinlike areas along lakes and streams,

where surface or subsurface water accumulates

in the root zone for at least part of the year.

Climate.—Saturation of the soil in this ecosystem during at least part of the growing

season is strongly related to local topography or

geology, rather than to the climate of the ecosystem. However, there must be adequate annual precipitation on the site or runoff from

higher areas to create the soil moisture conditions necessary to the development of the

meadows. The temperature regime of meadows

is generally that of the surrounding areas, yet

in some cases, meadows are the sites of frost

pockets in which temperatures deter establishment of some forest stands as effectively as

intermittent high moisture in the rooting zone.

Vegetation.—Grasses, sedges, rushes, and in

some cases, phreatophytic shrubs dominate the

mountain meadows ecosystem. Under the best

conditions 70 percent of the ground is covered

by vegetation, more than three-fourths of which

may be perennial grasses. Sedges may constitute as much as 15 percent of the cover. Perennial forbs with showy flowers make up only

about 10 percent of the cover. The proportions

of the various growth forms are easily manipulated by the degree and timing of grazing.

Fauna.—In many places this ecosystem contains lakes and streams that provide water for

wildlife, and it is usually more productive of

herbage than surrounding areas. Thus, it

attracts fauna daily from the larger ecosystems

aâ^iiJ

rfil Ml '^1 ) .-tiáto :->.i. f »»..«K.^rv.i.->r^v.«r<-v^v ^^ »^

F-437868

Figure 28.—Rangeland in the mountain meadows ecosystem in the Southwest, surrounded by stand of Engelmann

spruce and subalpine fir in the fir-spruce ecosystem.

49
in which it occurs. The wetter meadows, especially those with streams or permanent lakes,

are a home for such wildlife as beaver, waterfowl, and fish. The fauna of intermittently wet

meadows may shift as moisture conditions

change. For example, the burrowing rodents

and the predators which feed upon them use

the meadows only during the drier periods.

Deer, elk, and moose are among the large

mammals which, though using heavy timber

sites for cover, depend heavily upon meadows

for food. In large expanses of forest and rangeland, the meadows are about the only suitable

habitat for the nesting of migratory waterfowl.

Soils.-—Soils of mountain meadows commonly

have been, and are currently, recipients of

alluviation, illuviation, or glaciation products

from above. Consequently, no classification by

soil orders is attempted for this ecosystem.

Land me.—Small, high-elevation mountain

meadows commonly have not been cultivated.

Only at lower elevations or in more accessible

areas have meadows been converted to hayland

or drained and farmed. On the other hand,

many small mountain meadows have been obliterated by roadbuilding and trails made by

horses used for recreation. Disturbances to

plant cover have, in some cases, resulted in the

cutting of streambeds^ to such depths that the

water table has been lowered. Where this has

happened, the meadows have lost their productive herbaceous cover and have been invaded by

brush or lodgepole pine stands.

Because of the potentially high productivity

of mountain meadows, those of considerable size

warrant sophisticated range management and

investment in physical improvements. Where

water flows or permanent pools occur in the

drainage lines through meadows, consideration

should be given to an intensive form of meadow

management, including provision for wildlife

and certain types of recreation.

Productivity Classes

The length of the wet period and the depth

of soil largely regulate productivity in the

mountain meadows ecosystem. Sedge and hairgrass meadows are the most productive, yielding 3,000 pounds or more of herbage per acre.

Another type of meadow is one dominated by

such shrubs as willow. Such meadows are moderate to poor producers of grass forage but a

good source of brov/se for deer, moose, and

other animals. The least productive meadows

are those on soils whose wet season is short or

on shallow soils or soils that are shallow in

effect because of a tight soil horizon near the

surface which restricts drainage. Such shallow

and temporarily wet sites commonly produce

only unpalatable species of rush.

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows:

ProducMvity Pounds Productivity Pounds

class per acre class per acre

1- -^ - -- 8,000-=4000 3 1,000-2,000

2 -.2,000-3,000 4 0-1,000

NO, 38.—THE PLAINS GRASSLANDS ECOSYSTEM

Physiography,—The plains grasslands ecosystem, also known as the Great Plains, occurs

on a broad belt of high land which slopes gradually eastward and down from an altitude of

5,500 feet near the eastern foothills of the

Rocky Mountains to an altitude of 1,500 feet in

the Central States, where it gives way to the

prairie ecosystem. The most striking feature

of the ecosystem is the phenomenal flatness of

the interstream areas, which make up a great

expansive fluviatile plain or alluvial slope. The

eastern margin has been most exposed to erosion, being near the trunk line of drainage and

in a climate of greater rainfall than the western edge. The plains grasslands ecosystem of

280 million acres is larger than any other

vegetation region in the United States.

Œma^e.—Temperatures vary considerably,

the frost-free season ranging from less than

100 days in the north to more than 200 days in

Texas. The ecosystem is characterized by periodic droughts. Average annual precipitation

ranges from 10 inches in the north to more than

25 inches in the south, 68-80 percent of the

precipitation falling in the warmest months.

Normal annual pan evaporation is roughly four

times the precipitation. Precipitation ranges

from about one-third to one-half of potential

evaporation.

Vegetation,-—Short, warm-season grasses

predominate in this ecosystem, and there is a

minor interspersion of forbs and shrubs. Vast

stretches are dominated almost exclusively by

blue grama, buffalo grass being a companion in

many areas. However, the eastern part of the

ecosystem is dominated by grasses of medium

stature, such as western wheatgrass and needlegrass. The occasional shrubs include juniper,

silver sagebrush, silver buffaloberry, and skunkbush sumac in the northern reaches and rabbitbrush and mesquite in the southern part. Forbs

are generally quite common, but many are

ephemerals.

Fauna,—Kugê herds of American bison once

50
Figure 29.—Cattle on productive rangeland in the phenomenally flat plains grasslands ecosystem.

F-504689

migrated with the seasons across the central

plains. Currently, the pronghorn, or antelope,

is probably the most abundant large mammal,

but mule deer and white-tailed deer are often

abundant where brush cover is available, as

along stream courses. The white-tailed jackrabbit occupies the northern part of the ecosystem and the black-tailed jackrabbit, the area

south of Nebraska. The desert cottontail is

widespread. The lagomorphs, the prairie dogs,

and a variety of small rodents are preyed upon

by the coyote and a number of other mammalian

and avian predators, one of which, the blackfooted ferret, is classed as an endangered

species. The wolf once existed on the plains in

great numbers, feeding to a considerable extent upon bison.

The lesser prairie chicken, formerly abundant, is now classed as a rare species. Sage

grouse, greater prairie chickens, and sharptailed grouse are present in the area. Among the

many smaller birds are the horned lark, lark

bunting, and western meadowlark. The endangered golden-cheeked warbler is in the southeastern portion of the ecosystem in places

where the Ashe juniper is present. Stock pond

construction has created an important "duck

factory" in the northern Great Plains.

Soils.—The soils of this ecosystem are varied.

Mollisols occur from the Canadian border to

the southern boundary of the ecosystem in

Texas, as do Entisols. Alfisols and Aridisols are

less extensive and are mostly in the southern

portion.

Land use.—Large areas of the most productive sites have been converted to crop farming ;

the remainder is rangeland.

Productivity Classes

Class 1.—Productivity class 1 is characterized by the wheatgrass-bluestem-needlegrass

community, which is adjacent to the northcentral part of the prairie ecosystem and receives

more rainfall (about 18 inches) than other

areas of the plains grasslands ecosystem. Western wheatgrass, big bluestem, and needlegrass

are characteristic, medium-tall to tall grasses

being dominant. Woody plants are absent or

grow sparingly along streams. Herbage production ranges up to 2,000 pounds per acre, 70 percent being forage. Fifty percent utilization is

considered appropriate for maximum sustained

yield.

The soils of class 1 areas are Mollisols which

have the characteristic carbonate horizon but

have a weak, thin horizon of accumulated clay

characteristic of Argiustolls; they are gently

sloping. Approximately one-fourth of the land

is in native grasses. The other three-fourths is

used for growing grain as a cash crop.

Class 2.—The wheatgrass-needlegrass community of the western Dakotas is characteristic

of productivity class 2. It occurs as a moderately dense, short or tall, wide expanse of gently

to moderately rolling grassland dissected by

small, deeply eroded, intermittently flowing

streams. The dominants are western wheat61
grass, blue grama, needle-and-thread, and green

needlegrass. Forbs and woody plants oceur

sparingly. Herbage production ranges up to

1,500 pounds per acre; 70 percent being forage.

Fifty percent utilization is considered appropriate for maximum sustained yield.

The soils of class 2 areas are Mollisols, including Argiborolls plus Haplustolls that are

gently sloping. Most of the soils have a subsurface horizon that is high in content of bases and

a subsurface horizon in which clay has accumulated. Precipitation averages 15 inches per year.

Three-fifths to three-fourths of the land is in

native grasses grazed by cattle and sheep. Irrigation is common along streams.

Class 3,-—The grama-needlegrass-wheatgrass and wheatgrass-grama-buffalo grass

communities in the 12-inch precipitation belt

represent this productivity class. Class 3 areas

are rather short, fairly dense grasslands dominated almost exclusively in many places by blue

grama. Associated dominants are western

wheatgrass, needle-and-thread, and buffalo

grass. Juniper occurs in some places. Herbage

production ranges up to 1,000 pounds per acre,

60 percent being forage—-50 percent of the

herbage is short-grass plants. Fifty percent

utilization is considered appropriate for maximum sustained yield.

The soils of class 3 areas are mainly gently

to moderately sloping Mollisols and Entisols

which are intermittently dry for long periods

during the warm season and usually have a horizon of accumulated clay and calcium carbonate.

The areas also include Aridisols. About threefourths of the land is in grass, and about 5

percent is dry-farmed. The remainder is either

irrigated or classiñed as open woodland of

western redcedar.

Class Jf,—T\ÚB production class is characterized by the grama-buffalo grass and the mesquite-buffalo grass communities of the southcentral Great Plains. Annual precipitation

averages 20 inches; exceeding that of northern

areas of this ecosystem. However, high average

annual temperatures cause much of the moisture to evaporate. Blue grama and buffalo grass

are, exclusively, the dominant herbaceous

plants. They form a fairly dense grassland.

Mesquite commonly occurs in the southeastern

portion of this ecosystem. Herbage production

ranges up to 500 pounds per acre, 60 percent

being forage. Sixty percent utilization is possible because of the outstanding resistance of

the native short grasses to damage by grazing ;

this is partly due to their low stature.

The soils are mainly Mollisols and Alfisols,

and there is a scattering of Entisols. The topography ranges from gently sloping to moderately sloping. The most common characteristic

of these soils is that they are intermittently

dry for long periods. The Mollisols and Alfisols

have a subsurface horizon in which salts or

carbonates and clays have accumulated. About

three-fifths of the land is in grass, and onefourth is dry-farmed. The remainder is under

irrigation.

HERBAGE PRODUCTION

A summary of herbage production in the

eGOsystem follows:

Productivity Pounds Productivity Pounds

class per acre class per acre

1.--::.--. .1,500-2,000 3 500-1,000

2 :.::: 1,000-1,500 4 0-500

NO. 39.—THE PRAIRIE EGOSYSTEM

Physiography,—The prairie ecosystem is a

relatively large contiguous grassland which lies

between the deciduous forests of the East and

the short-grass plains of the West, on the flat

to rolling hill land of the Central Lowland.

Topographic relief delineates the boundaries of

this ecosystem/the 1,500-foot contour being the

western boundary and the 500-foot contour, the

eastern boundary. The northern limits extend

into Canada, and the southern limits extend into

southern Texas. Most of the lands of this ecosystem, excluding those south of the Missouri

River, are those of young glacial drifts and

dissected till plains. The area south of the Missouri River is older, has well-developed drainage systems, and is flat to rolling hill land.

Climate,-—The climate varies widely in this

ecosystem. The length of the frost-free season

varies from less than 120 days in the north to

almost 300 days in the south. On the east, from

Texas to Indiana, the prairie boundary lies

close to the 40-inch isohyet. On the west, the

southern boundary is near the 30-inch isohyet ;

while further north, the prairie reaches the 20-

inch isohyet. In general, more precipitation occurs in the warmer part of the year. During the

growing season the amount of precipitation,

on the average, varies from 60 percent of potential evaporation in the west to 100 percent in

the east.

Vegetation,—The pr^i^i^ ecosystem is known

to many as the tall-grass or true prairie. Bluestems constitute about 70 percent of the vegetation and reach heights of 5 to 6 feet in lowland

areas. Large numbers of flowering forbs are

present but are usually overshadowed by the

grasses. Most of the plants are classified as

warm-season plants. Woody vegetation is rare.

Willow occurs in some places in exceptionally

moist areas of the northern part of the ecosys52
tern, and needle-leaved evergreens and broadleaved deciduous trees are scattered in the

southern part. Deciduous trees are common

along permanent streams in the eastern portion.

Fauna.—Bison once grazed at the western

margin of the tall-grass prairie, and the pronghorn, or antelope, is still present there. Jackrabbits are common residents of the prairie,

and cottontails are present where there are

streams and cover. Burrowing rodents include

ground squirrels, prairie dogs, pocket gophers,

and many smaller rodents. Burrowing predators

include the badger and the black-footed ferret,

now considered an endangered species. The

Texas red wolf is classed as an endangered

species on the southern border of the ecosystem.

The coyote is still common.

The northern portion of the prairie ecosystem is an important breeding area for a number

of species of migrating waterfowl. Many of these

migrators winter on the coastal plains of Texas

and Louisiana. Mourning doves have become

abundant as shelterbelt plantings have developed. Among the gallinaceous birds, the sharptailed grouse, greater prairie chicken, and bobwhite are present in fair numbers. However,

the northern greater prairie chicken is considered a rare species, and Attwater's prairie

chicken, on the Gulf coast of Texas, is listed

as an endangered species.

Soils.—The soils of the prairie ecosystem are

primarily MoUisols. There are smaller areas

of Entisols and one small area of Vertisols.

Most of the soils have dark upper horizons.

Land use.—Most of the ecosystem has been

converted to cropland.

F-622879

Figure 30.—The dominant grasses in the lowland areas of the prairie ecosystem—sometimes referred to as the true

prairie or tall-grass prairie—can be taller than a man.

68
Productivity Classes

Class 1.—This productivity class is characterized by lands that are level, have deep, fertile

soils, and receive adequate moisture for maximum production of vegetation. Big bluestem,

little Muestem, switchgrass, Indian grass, and

side-oats grama are the dominant plants. Herbage production ranges from 4,500 to 6,000

pounds per acre on the bluestem prairie.

Seventy percent of the herbage is forage. Fifty

percent utilization is most satisfactory for

maximum sustained yield. The soils are Mollisols and have dark surface horizons that are

rich in organic matter. About 10 to 15 percent

of this area is in permanent pasture of tame

and native grasses. The remainder of the area is

used for growing corn and other feed grains.

Class 2,—This productivity class is characterized by lands that have gently sloping, clayey

soils and receive adequate moisture for the

growth of herbaceous plants. However, summer

droughts are common. Little bluestem and

Texas needlegrass are dominants in the blackland prairie community, in Texas. Seacoast

bluestem and coastal sacahuista are dominant

in the bluestem-sacahuista prairie community

of the coastal plains of Texas and Louisiana.

Herbage production averages 3,000 pounds per

acre, of which 70 percent is forage. Fifty percent utilization is considered satisfactory. The

soils are Vertisols that have a black or darkgray surface horizon. About two-thirds of the

area is in cropland, and one-sixth is in pasture.

The remainder is in abandoned fields or narrow

strips of woodland along streams.

Class 8,—The cedar glades and Nebraska

Sand Hills prairie communities represent this

productivity class of the prairie ecosystem.

They are medium-tall grasslands with an element of dwarf to medium-high shrubs (broadleaved and cedar shrubs). These grasslands

occur on gently to moderately sloping areas.

Dominant species in the cedar glades community include little bluestem, big bluestem, and

Indian grass. Big bluestem, sand bluestem, and

prairie sandreed are dominants on the Nebraska

Sand Hills prairie. Herbage production averages 2,500 pounds per acre, 70 percent of which

is forage. Fifty percent is usable to maintain

maximum sustained yield.

The cedar glades lie in a 42-inch precipitation

belt, but the soils are shallow and droughty. The

soils in the Nebraska Sand Hills show weak

pedogenic development and, consequently, become dry quickly during periods of drought.

The cedar glades soils are Ultisols that have a

thick horizon of accumulated clay, and the soils

of the Nebraska Sand Hills are Entisols that

contain easily weatherable materials. Both

areas are droughty for extended periods each

year. Most of the class 2 areas are in native

grass ranges grazed by livestock.

Class 4»—This productivity class is characterized by grasslands that differ from the typical

prairie ecosystem by having dwarf shrubs and

scattered open groves of deciduous trees. The

sandsage-bluestem prairie and Fayette prairie

communities represent this class. Herbage

yields in these units average 1,500 pounds per

acre. Forage yields are 60 percent of herbage

yields. Forty percent utilization is satisfactory.

The dominant species in the sandsage-bluestem

prairie community are little bluestem, sand

bluestem, sand sagebrush, and hairy grama.

On the Fayette prairie dominant grasses are

little bluestem and buffalo grass, and dominant

trees are oak and hickory. About one-fifth of

the class 4 area remains in native range grazed

by beef cattle. The remainder is used for growing grains as cash crops.

NO. 40.—THE DESERT GRASSLANDS ECOSYSTEM

Physiography,—The desert grasslands ecosystem occurs in scattered areas on tablelands

of moderate to considerable relief in the Colorado Plateaus province in Arizona, New Mexico,

and Utah and on the plains with low mountains

of the Mexican Highland section in southwestern Texas. Elevations range from 5,000 to

7,000 feet. These tablelands or plateaus are

moderately to severely dissected by rugged

canyons.

Climate,—The amount of precipitation in

this ecosystem is low, ranging from 8 to 12

inches annually. Usually more than half falls

in the warmer part of the year. During the

frost-free season, the evaporation potential is

five or more times the normal rainfall. The

frost-free season ranges from over 200 days in

Texas to about 120 in Utah.

Vegetation,—The grass life-form predominates on these plateaus at intermediate elevations, and shrub life-forms are dominant at

higher and lower elevations. In transition zones,

shrubs give way to galleta to black grama to

blue grama. Consociations of these species occur, but almost pure stands are the rule. Tobosa

replaces galleta in the southern extensions in

•Texas of this ecosystem, and three-awn becomes

the dominant in the northern extensions in

Utah. In its northern extensions this ecosystem

is a more open grassland with low shrubs.

Fauna.—Pronghorn, or antelope, are the primary larger mammals in the desert grasslands

ecosystem. Mule deer also occur. The coyote and

bobcat are among the chief animal predators.

54
F-489029

Figure 31.—The grass life-form predominates in the desert grasslands ecosystem, but mismanagement can result in

an increase in the occurence of cactus and desert shrubs.

They prey upon black-tailed jackrabbits, cottontails, wood rats, and a large number of small

rodent species, such as the kangaroo rat and

the deer mouse. Scaled quail range into the

grasslands, especially where brush has made

an invasion. Among the smaller birds of the

ecosystem are the horned lark, several sparrows, the loggerhead shrike, and nighthawks.

Avian predators include the golden eagle, great

horned owl, and various hawks.

Soils.—The soils are almost entirely Entisols

that have no pedogenic horizons and Aridisols

that lack pedogenic horizons and are never

moist for as long as three consecutive months.

LMnd use.—Most of this ecosystem is used as

rangeland.

Productivity Classes

Class 1.—The grama-tobosa prairie community characterizes this productivity class.

It is an open grassland of rather low growth

and scattered succulents. Herbage production is

750 to 1,000 pounds per acre. Woody plants

are absent or occur sparingly. Blue grama and

tobosa are the characteristic dominants. The

soils are mainly Entisols (Torriorthents) that

are shallow (20 inches to bedrock), loamy or

clayey, never moist for as long as three consecutive months, and moderately sloping to

steep. Class 1 areas also include some Aridisols

(Calciorthids plus Torriorthents) that are

gently sloping. The class 1 portion of the desert

grasslands ecosystem is used as rangeland for

livestock.

Class 2.—The grama-galleta steppe community of northern Arizona and New Mexico

characterizes this productivity class. Herbage

production averages 500-750 pounds per acre.

Blue grama and galleta dominate this low to

medium-tall grassland. Woody plants such as

Mormon tea and succulents such as Opuntia

and Yucca spp. occur more commonly than in the

grama-tobosa prairie community. This community is highly responsive to rainfall, so production varies considerably. The soils are mainly Aridisols (Haplargids and other Aridisols

plus Torriorthents) that are gently to moderately sloping and are never moist for as long

as three consecutive months. This class also occupies some areas of Entisols (Torriorthents).

Less than one-third of class 2 land is pri65
vately owned, the remainder being in Indian

reservations or held by the Federal Government. Most of the areas are native rangeland.

About 2 percent of the land is used for irrigation or dryland farming.

Glass 5.—The open grassland with low shrubs

known as the galleta~three-awn shrubsteppe

community of southeastern Utah characterizes

this productivity class. Herbage production

averages 250-500 pounds per acre. Three-awn,

galletta, sand sagebrush, and Mormon tea are

the major species; Numerous other species of

grass, forbs, and woody plants occur, but less

commonly. The soils are mainly Aridisols (Calciorthids plus Torriorthents) which slope gently or moderately and have a horizon in which

large amounts of calcium carbonate or gypsum

have accumulated. In Utah, class 3 areas also

are on Entisols. The class 3 portion of the

desert grasslands ecosystem is used as rangeland for cattle and sheep.

Class ^.—Some parts of the desert grasslands

ecosystem occur on relatively shallow sandy

soils and are droughty. This situation occurs

in grama-tobosa prairie areas and in galletathree-awn shrubsteppe areas. These droughty

areas characterize productivity class 4. The

dominant species remain the same or almost

the same as in class 1 and class 3, but herbage

production drops to 0 to 250 pounds per acre

and the vegetation is usually very sensitive to

hard use. The soils are gently to moderately

sloping Entisols that have no pedogenic horizon, are loamy or clayey, and have a regular

decrease in organic matter content with depth.

Class 4 areas are used as grazing lands for

sheep and cattle.

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows:

Productivity Pounds Productivity Pounds

class per acre class per acre

1 ..........750-^1,000 3 .250- 500

2 - . : - 500- 750 4 0- 250

NO. 41 .—THE WET GRASSEANDS ECOSYSTEM

Physiography,—-The wet grasslands ecosystem is characterized by the narrow belt (1-50

miles wide) of coastal wet prairies and marshes

stretching from the Mexican border to Long

Island, N. Y., exclusive of the coastline of

Florida, Georgia, and the Carolinas. It is also

characterized by the Everglades and the palmetto prairie of southern Florida, the tule

marshes of the low fluviatile plain in the California Trough; and the flood plains of the Great

Salt Lake and other lakes of the Intermontane

Plateaus.

The coastal prairie is a plain of clay alternating with sands and is almost untouched by

erosion, except for the steep-sided channels of

transverse streams, whose bottoms may be 30

to 40 feet below sea level. The Everglades are a

permanent swamp. The palmetto prairie, adjacent and to the north, is slightly drier. Both

occupy an extensive, almost flat, marl and limestone shelf generally covered with a few feet

of muck and a little sand. The tule marshes of

central California are the result of the Sacramento and San Joaquin Rivers forming natural

levees—at low altitudes (10 to 60 feet above

sea level)—which entrap water along these

rivers. There are numerous lakes along these

rivers, and many have been drained and are

used as cropland. These lakes, in the broad, flat

silt floors of basins with internal drainage, are

of the playa type.

Climate.—The wet grasslands ecosystem

varies so greatly geographically that any generar climatic description is of questionable

value. Rainfall in the Central Valley of California may be less than 10 inches; thus, the wet

conditions in the **tule marshes" are due primarily to topography and runoff. Other areas

in the ecosystem receive much more precipitation, which amounts to as much as 60 inches

or more in the Everglades. The length of the

frost-free season ranges from practically all

year in extreme southern Texas and Florida

to less than 200 days in the northern end of the

ecosystem, on the upper Atlantic coast. Potential evaporation ranges from many times the

rainfall in California to less than the annual

rainfall in the eastern portion of the ecosystem.

In the farflung coastal portions of the ecosystem, intrusion of salt water may have more

efliect on the vegetation than does climate or

soil

Vegetation.—The coastal prairies (marshes)

are occupied by cordgrasses, including smooth

cordgrass and saltmeadow cordgrass (the latter being more prevalent on the Atlantic coast),

saltgrass, and a few forbs. The vegetation

forms a medium-tall to very tall grassland,

usually dense. The palmetto prairie and Everglades are dense, medium-tall to tall grasslands.

There are scattered palms and shrubs on the

palmetto prairie and scattered low to mediumtall broad-leaved evergreen trees and shrubs in

the Everglades. The major species of the palmetto prairie are wire-grass and saw-palmetto.

The major plants of the Everglades grassland

are sawgrass and three-awns. The vegetation

of the tule marshes is a tall graminoid vegeta56
tion consisting of tules and other bulrushes,

cattail, and soft flag. Several species of sedges

occur less commonly.

Fauna.—The fauna of the wet grasslands

ecosystem varies as much as its geography. The

ecosystem, especially its open-water and more

marshy areas, serves as a seasonal home for

tremendous numbers of migratory waterfowl.

The Central Valley of California and the coastal

marshes of Texas and Louisiana are prime

examples. Endangered species, including the

whooping crane, the Texas red wolf, and

Attwater's prairie chicken, use the Texas

coastal area, and the American alligator is a

yearlong resident of the Gulf coast and the

Everglades. Other endangered species that formerly made more use of the ecosystem are the

Florida panther of the Southeast and the tule

elk that once ranged into the California tule

marshes. Most of the fauna are tolerant of a

moist or wet environment. Many species from

adjacent prairies and forests make extensive

use of the wet grasslands. Fresh- and brackishwater ñshes, reptiles, and amphibians are abundant and varied.

The Everglades has a wide variety of influent

species from adjacent palmetto prairie, cypress

swamp, magnolia forest, and mangrove areas.

A slight change in the water level causes

marked changes in the habitat and the fauna.

Among the many mammals are the white-tailed

deer, Florida panther, black bear, raccoon, bobcat, opossum, skunks, bats, marsh and swamp

rabbits, cotton rat, and fox squirrel. Avian

fauna is very varied ; many influent species are

cited in descriptions of adjacent areas. Before

the water level in much of the Everglades was

lowered by drainage, the area was the home of

large numbers of herons, egrets, limpkins, mottled ducks. Everglade kites, and other birds.

Now the Florida great white heron is classified

as rare. The Everglades kite is classified as

endangered.

Soils.—Soils in this ecosystem are extremely

varied, all soil orders found in the continental

United States being represented. Entisols are

prevalent in the Central Valley of California.

Land use.—Because of wide variations in site

conditions, there is no consistent pattern of land

use in this ecosystem. It is used for hunting,

fishing, trapping, crop production, improved

pasture, rangeland, and other purposes.

F-622880

Figure 32.—A forest of cabbage palmetto forms the background of this range area in the wet gn^asslands ecosystem

in southern Florida.

57
Productivity Classes

Class i.—Productivity class 1 is characterized by the southern cordgrass prairie community, which is the most productive vegetation

unit in the wet grasslands ecosystem. The

average herbage yield is 10,000 pounds per

acre. Smooth cordgrass is the major species

and is considered highly palatable to cattle.

Other common plants are Carex spp., saltgrass,

and tules. Forbs and shrubs range from none

to few. The construction of ^Svalkway" levees

has greatly improved the accessibility of the

rangeland to livestock.

The soils are mainly Histosols (plant residues

that are moderately decomposed; gently sloping) and Mollisols (Haplaquolls plus Udipsamments and Humaquepts) which are wet and

have a thick, nearly black surface horizon and

gray subsurface horizons.

About 50 percent of the land of the southern

cordgrass prairie is used for growing rice and

tame forage, including alfalfa and grasses.

This part of the ecosystem is also used for hunting, fishing, and trapping.

Class 2.—The Everglades characterizes productivity class 2. Herbage yields range from

6,000 to 9,000 pounds per acre. However, most

of the herbage is Jamaica sav/grass, a species

of little to no value for grazing by cattle. About

10 percent of the Everglades has been converted

to pastures of desirable herbage, which yield

approximately 8,000 pounds per acre. Other

plants in native stands are three-awns, Boelimeria cylindrica, tules, and cattails. Woody

plants occur in the bayheads, the most common

being sweetbay and redbay.

The soils are mainly Histosols (plant residues

moderately decomposed or highly decomposed;

gently sloping) which are wet organic (muck)

soils. About 50 percent of the 7,200 square

miles of the area is in Indian reservations,

National Parks, and game refuges. Hunting,

fishing, and other recreational activities are

major uses of much of the Everglades. About

5 percent is cropland, and 15 percent is in

pasture.

Class 3,—The palmetto prairie and northern

cordgrass prairie characterize this productivity

class. Herbage yields range up to 6,000 pounds

per acre—few data exist for the northern cordgrass prairie, so this is a broad estimate at

best. Most of the class 3 land is intensively

developed for resorts and recreation. The major

plants of the palmetto prairie community are

wiregrass, hairawn muhly, creeping bluestem,

miscellaneous bluestems, and saw-palmetto.

The soils are mainly Entisols (Psammaquents plus Hapiaquads and Quartzipsamments) that are loamy fine sand or coarser

material and are permanently or seasonally

wet. Other soils of class 3 are Alfisols (Ochraqualfs plus Psammaquents) and Spodosols

(Haplaquods plus Quartzipsamments) which

are sandy and have mottles of iron and manganese compounds. Restricted drainage is a

problem.

Most of the class 3 land is used for grazing

by cattle. Thirty to 50 percent of the area in

pastures has adequate water-control systems

and a high cattle-carrying capacity. The trend

is to more improved pastures. Winter vegetable

gardens and citrus and other subtropical fruit

orchards are increasing in importance.

Class i,—The tall, graminoid vegetation of

the tule marshes in the Sacramento and San

Joaquin Valleys and on old beds of the Great

Salt Lake and large lakes in Nevada characterizes this productivity class. Few data are

available on yields of herbage. The major species are tules and other bulrushes and cattails.

Ca7^ex spp. occur in some places.

The soils were primarily Histosols (highly

decomposed plant residues) but are now classified as Entisols (Xerorthents plus Durixeralfs,

Haploxeralfs, Xerofluvents, Palexeralfs, and

Haplaquolls) because of extensive draining and

the use of the land for growing irrigated crops.

Very few of the tule marshes remain. Those

that do are in high demand as places for hunting ducks and geese. Most of the class 4 land is

farmed. Important crops are asparagus, sugar

beets, potatoes, corn and other grains, and hay

—all grown within the levee systems which

protect the land against flooding.

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows :

Productivity Pounds

class per acre

1. :. 9,000-12,000

2 ..... ..6,000- 9,000

Productivity Pounds

class per acre

3 3,000-6,000

4 0-3,000

NO. 42.—THE ANNUAL GRASSLANDS ECOSYSTEM

Physiography.—The annual grasslands ecosystem is characterized by the California steppe

vegetation community, which occupies extensive areas in the Central Valley of California

and along the Pacific Coast. This community is

often referred to as the California annual or

foothill grasslands. These grasslands iorm a

discontinuous zone between the upper limits of

the valley floors and the western hardwoods

ecosystem, which occurs mainly at elevations

between 500 and 2,000 feet above sea level. The

Sierra-Cascade Mountains are on the east, and

58
the California Coast Ranges are on the west.

The California steppe occupies the lower foothills of these ranges. The foothills are rolling

hills interspersed with numerous level valleys.

These lands have their origin in colluvial

material from the mountain ranges and fans of

alluvial material. The flow of alluvial and colluvial material is m.uch stronger from the

Sierra-Cascade Mountains on the east than

from the Coast Ranges. Consequently, the accumulation is much greater and more extensive

on the eastern side of the Central Valley than

on the western side; it is more obvious in the

San Joaquin Valley than in the Sacramento

Valley. Numerous small springs and seeps occur

throughout the ecosystem, the water table being

close to the surface in the bottoms of valleys.

Climate.—Most of the annual grasslands ecosystem has a climate of hot, dry summers and

mild, relatively moist winters. The length of

the frost-free season is 250-300 days. Precipitation ranges from less than 10 inches at low

elevations in the southern portion to more than

40 inches at the higher elevations at the northern border. Little rain falls in the summer. Up

to three-fourths of the annual precipitation

may fall in the period December-March. Potential evaporation during the warmest months is

often many times the precipitation. These

climatic conditions are extremely favorable for

the growth of cool-season annuals, which make

up practically all the herbage.

Vegetation.—The vegetation of the ecosystem is of grass life-form. Annual grasses,

mostly introduced, dominate the cover. The

dominant plants are wild oats, several species

of brome, wild barley, and fescue. Perennial

bunchgrasses, where they occur, include needlegrasses, creeping wildrye, and pine bluegrass.

Perennials are scarce or absent at lower elevations and increase at the upper elevations of

the ecosystem. Forbs, with the exception of

filaree, are numerous but of secondary importance. Many people believe the prehistoric vegetation was perennial, but historical evidence is

meager and reconstruction of the original

perennial vegetation (if it were perennial), if

it can be done at all, is accomplished only with

complete protection and considerable effort. The

earliest references, from the early 1800's, indicate that the California steppe was dominated

by annual grasses. In this ecosystem, annual

plants, with their short life cycle and rather

shallow root system, have probably shown the

most consistent and profitable response to range

fertilization.

Fauna,—Intensive agricultural development

has changed the fauna of the annual grasslands

ecosystem. Many species have been eliminated

or ''moved up in the hills." The California

grizzly, wolf, and pronghorn, or antelope, have

long since disappeared, and the San Joaquin

kit fox is classified as an endangered species.

Several species of mule deer occur in areas

with brush. The California quail is now numerous mainly in areas where brush or rock outcrops provide cover. The mourning dove occurs

throughout the area. Common mammals include

the Beechy ground squirrel, cottontail, blacktailed jackrabbit, mice, and kangaroo rats.

Many species, such as the coyote and bobcat,

occur in, or enter from, the adjacent woodlands.

Common birds include the horned lark, v/estern meadowlark, western kingbird, mockingbird, loggerhead shrike, house finch, lesser goldfinch, red-shafted flicker, and scrub jay. The

rattlesnake is an important predator of rodents.

The roadrunner feeds partly on reptiles. Other

avian predators include the golden eagle, redtailed hawk, and Cooper's hawk. A number of

snakes and lizards are present. Additional species occurring in this ecosystem are found in

the western hardwoods ecosystem.

Soils.—The soils of this ecosystem are mostly

Entisols and Alflsols. In general, the Entisols

are at the lower elevations of the Central Valley, and the Alflsols occur at slightly higher

elevations, away from the valley floor. A small

area of Aridisols occurs in the more arid south»

ern portion of the San Joaquin Valley.

Land use.—The land at the lower elevations

of what was the annual grasslands is mostly

irrigated and makes up the bulk of one of the

richest agricultural areas in the world—the

Central Valley of California. At slightly higher

elevations, some land is dry-farmed, but the

area is mostly used for grazing by cattle. The

area receives very heavy recreational pressure

from nearby metropolitan areas, including Los

Angeles and San Francisco.

Productivity Classes

Herbage production is greater on the northern than on the southern annual ranges of

California. This is due mainly to more precipitation in the north. However, the productivity

classes are basically the same for both areas.

The herbage yields reported in the following

paragraphs are based mostly on research at the

San Joaquin Experimental Range of the USDA

Forest Service, in the Sierra Nevada foothills.

The Experimental Range, 25 miles north of

Fresno, is in the southern part of the ecosystem. The ranges in this ecosystem are very

responsive to rainfall, which varies considerably. Changes in the amount of rainfall can

cause a variation of well over 100 percent in

herbage production from year to year.

Class 1.—The vegetation of the swales characterizes this productivity class. Herbage yields

range up to 4,400 pounds per acre. The swales

comprise roughly 10 to 15 percent of the annual

grasslands. The dominant plants are foxtail

fescue, Mediterranean barley, clovers, filaree,

and rushes. Considerable fluctuation in species

59
F-447499

Figure 33.—Rangeland in the annual grasslands ecosystem in California. Annual grasses dominate the ground cover;

the trees are oak.

composition of the herbage may occur rapidly

as a result of climatic fluctuation. This site is

probably more stable than the other sites in this

ecosystem and usually receives intense use for

grazing.

The soils are mainly Entisols (dark gray,

sandy clay loams with fairly good water-holding capacity, better than those of the slopes).

The swales receive much seepage water, to the

point of being saturated in wet winters.

Class 2.—The vegetation on the gentle slopes

characterizes this productivity class, producing

2,200 to 3,300 pounds of herbage per acre. The

vegetation of this class occupies the area just

above the swales and is on a slope of 10 percent

or less. This class makes up about 10 percent

of the California steppe. The dominant plants

in the southern portion are foxtail fescue, soft

chess, Mediterranean barley, and clovers. Wild

oats are dominant in the northern part. The

land in this class, along with the swales, usually

receives the hardest grazing use.

The soils are Alfisols and Entisols (Xerorthents)—fine sandy loams that represent the

transition from transported soils in the swales

to soils developed in place on the slopes.

Class 3.—Open, rolling upland sites where

herbage production averages 1,850 pounds per

acre represent this productivity class. These

sites are located on slopes with gradients of

10 to 25 percent and have a very open cover of

trees and only scattered rock outcrops. Dominant plants are soft chess, foxtail fescue, filaree,

and clovers. The soils are mainly Alfisols and

Entisols (Xerorthents that are sandy loams,

about 24 inches deep).

Class Jt.—This productivity class is characterized by the vegetation on the rocky, brushy,

rolling-to-steep sites where herbage yields

average 1,000 pounds per acre. These sites have

slopes of 25 percent or more and have numerous

rock outcrops or many shrubs and trees. They

60
differ considerably from place to place, including some productive soils, as well as some thin

sandy soils. This class makes up 60 to 75 percent of the California steppe. The dominant

plants are red brome, soft chess, and filaree.

The soils are Alfisols (Haploxeralfs plus

Xerorthents that are shallow and moderately

sloping to steep).

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows:

Productivity

class

Pounds

per acre

1 3,300-4,400

2 2,200-3,300

Productivity Pounds

per acre

S 1,100-2,200

4 . 0-1,100

NO. 44.—THE ALPINE ECOSYSTEM

Physiography.—The alpine ecosystem occurs

largely as an interrupted chain of stands on the

highest peaks in the Rocky Mountain and

Pacific Mountain Systems. Valley glaciers have

sculptured most alpine areas and provided open,

spectacular landscapes. Cirques, hanging tributaries, and various types of moraine are

common.

Climate.—The climate is rigorous. The average monthly temperature may be 3° C in January and 50° C in July. Frost may occur any

night during the summer. Precipitation is estimated to be 35-50 inches per year, falling

mostly as snow. Evaporation and wind movement are marked.

Vegetation.—Grasses and grasslike species

of rather low stature predominate, but the

number of associated forbs is large. Dwarf

willows occur, in some places, on the moist soils

of protected slopes and valleys.

Fauna.—The pika, pocket gopher, and yellow-bellied marmot are the only permanent

mammalian residents of the alpine ecosystem.

Summer visitors include mule deer, elk, mountain sheep, weasels, marten, chipmunks, and

the golden-manteled ground squirrel. The only

ri^'A».'.'friiA*ttÍÉitf'í'>jíf ^vlsSbfiFigure 34.—^Low grasses and grasslike plants predominate in the alpine ecosystem.

F-386B61

61
nesting birds are the horned lark, water pipit,

black rosy finch, rock wren, white-tailed ptarmigan, and robin.

Soils,—The soils of thiö ecosystem commonly

have no pedogenic horizons (Entisols), have

weakly differentiated horizons (Inceptisols), or

have a low supply of bases and an accumulation of amorphous materials in subsurface horizons (Spodosols). These cold soils normally

belong in the cryic great groups. The terrain

is sometimes referred to. as "fragile,'' because

of the ease with which the soils can be displaced

by horses* hooves on recreation trails or watereroded where ground cover becomes broken.

Land use,—This ecosystem provides summer

grazing for sheep under careful management.

Their deep snowpacks make areas in the ecosystem prime watersheds. The ecosystem provides opportunities for summer and winter

recreation and habitats for wildlife.

Productivity Classes

Class 1.—-Microtopography where moisture

tends to accumulate characterizes this productivity class. Sedges and tufted hairgrass are

characteristic dominants. Dwarf willows may

form an overstory. Herbage production ranges

from 900 to 1,200 pounds per acre. Eighty to

100 percent of the herbage could be considered

to be forage, but only 40-50 percent should be

used by grazing animals. Soils are normally

members of the '*Aqu'' suborders, are seasonally

wet, and are mottled with gray blotches.

Ctoss^.-—Upper and lower slopes fall within

this proäuctivity class. Dominant plants include

kobresia, sedges, alpine avens, tufted hairgrass,

and American bistort. Herbage production is

about 600-900 pounds per acre, of which 40

percent could be used as forage. Soils range

from Inceptisols on the upper slopes to Spodosols on the lower slopes.

Ctoss^.—-This production class is found, generally, on ridge tops and convex land surfaces.

The characteristic dominant plants include

alpine avens, sedges, dryas, moss silène, and

clovers. Herbage production ranges from 300 to

600 pounds per acre. No more than 10-15 percent of the herbage could be used for forage.

In many places, the soils are shallow, stony,

and coarse-textured. Pedogenic horizons are

absent or weakly developed.

Class 4"'—This productivity class occurs on

the shallowest soils of the fell-ñeld and the

boulder-field. It may occasionally include wet

areas where intensive frost action is taking

place. Dominant plants of the boulder-field are

lomatium, mountainsorrel, bluebell, sedges, and

alpine avens. The dominant plants of the fellfield include sedges and such pulvinate species

as alpine clover, Rocky Mountain railwood, and

moss silène.

Herbage production in this productivity class

varies from a few scattered plants to 300

pounds per acre. Forage is limited, but sheep

wander into the rock-field during dry years

to find such forage as bluebell.

HERBAGE PRODUCTION

A summary of herbage production in the

ecosystem follows:

Productivity Pounds pTodtictivity Pounds

class per acre class per acre

1 . ... :.^^^^ 3 ...3Ö0- 600

2... ......600- 900 4 0- 300

62
Appendix A—General References

Austin, M. E.

1965. Land resource regions and major land resource

areas of the United States. USDA Soil Conserv.

Serv., Agrie. Handb. 296, 82 p.

Daubenmire, R., and Jean B. Daubenmire.

1968. Forest vegetation of eastern Washington and

northern Idaho, Wash. State Univ., Wash. Agrie,

Exp. Stn., Tech. Bull. 60,104 p.

Fenneman, N. M.

1931. Physiography oí Western United States. 534 p.

McGraw-Hill Book Co., Inc., New York.

Kelsey, H. L., and W. A. Dayton.

1942. Standardized plant names. 675 p. J. Horace

McFarland Co., Harrisburg, Pa.

Küchler, A. W.

1964. Potential natural vegetation of the conterminous

United States. (Manual and map). Am. Geogr. Soc.

Spec. Publ. 36, 1965 rev., 116 p. New York.

Little, E. L., Jr.

1953. Checklist of native and naturalized trees of the

United States. USDA Forest Serv., Agrie. Handb.

41, 472 p.

1971, Atlas of United States trees. Vol. 1. Conifers

and important hardwoods. USDA Forest Serv.,

Misc. Publ. 1146.

Lull, Howard W.

1968. A forest atlas of the Northeast. USDA Forest

Serv., 46 p.

Miller, D. W., J. J. Geraghty, and R. S. Collins.

1962. Water atlas of the United States. Water Inf.

Cent., Inc., Port Wash., N.Y.

Shelford, V. E.

1963. The ecology of North America, 610 p. Univ. 111.

Press, Urbana, 111.

U.S. Department of Agriculture, Forest Service.

1967. Section 74: geographic forest types. In Forest

survey handbook. USDA Forest Serv. Handb.

4813.1, p. 74-74.2-3.

1973. The outlook for timber in the United States.

USDA Forest Serv. Forest Resour. Rep. 20, 367 p.

U.S. Department of the Interior, Geological Survey.

1967. Potential natural vegetation. USDI Geol. Surv.,

Nati. Atlas Sheet 90.

1969. Classes of land-surface form. USDI Geol. Surv.,

Nati. Atlas Sheet 62.

1969. Distribution of principal kinds of soils: orders,

suborders, and great groups. USDI Geol. Surv.,

Nati. Atlas Sheet 86.

1969. Major forest types. USDI Geol. Surv., Nati.

Atlas Sheet 182.

1969. Potential natural vegetation of Alaska. USDI

Geol. Surv., Nati. Atlas Sheet 89.

1970. The national atlas of the United States of

America. 417 p. USDI Geol. Surv., Wash.

Appendix B—References on Mammals and Birds

Bent, Arthur Cleveland.

1961. Life histories of North American birds of prey.

Part 1. 409 p. Dover Publ., Inc., New York.

1961. Life histories of North American birds of prey.

Part 2. 482 p. Dover Publ., Inc., New York,

1963. Life histories of North American gallinaceous

birds. 490 p. Dover Publ., Inc., New York.

Cadbury, J., and A. D. Cruickshank.

1942. Breeding-bird census, climax red and white

spruce forest. Audubon Mag. Sept.-Oct. 1942 Sect.

2:32

Ely, Alfred.

1939. North American big game. 533 p. Chas. Scribner's Sons, New York.

Johnson, D. W,, and E. P. Odum.

1956. Breeding bird populations in relation to plant

succession on the Piedmont of Georgia. Ecol.

37:50-62.

Kendeigh, S. C.

1946. Breeding birds of the beech-maple-hemlock community. Ecol. 27:226-245.

1961. Animal ecology. 468 p. Prentice-Hall, Inc.,

Englewood Cliffs, N. J.

Palmer, Ralph S.

1954. The mammal guide. 384 p. Doubleday and Co.,

Inc., Garden City, N. Y.

Rasmussen, D. I.

' 1941. Biotic communities of the Kaibab Plateau, Arizona. Ecol. Monogr. 11:229-275.

Shelford, Victor E.

1963. i?he ecology of North America. 610 p. Univ. of

111. Press, Urbana, 111.

Smith, W. P.

1944, Breeding bird census, white pine-hemlock forest.

Audubon Mag. Sept.-Oct. 1944 Sect. 2:24. 24.

Taylor, Walter P.

1956. The deer of North America. 668 p. The Stackpole Co., Harrisburg, Pa., and the Wildl. Manage.

Inst., Wash., D.C.

U.S. Department of the Interior, Bureau of Sport

Fisheries and Wildlife.

1968. Rare and endangered fish and wildlife of the

United States. USDI Bur. of Sport Fish., Resour.

Publ. 34.

63
Appendix C^—References Used in Deseribing Individual Ecosystems

WESTERN RANGE

SAGEBRUSH

Beetle, A, A.

1960. A study of sagebrush: the section tridentatae of

Artemisia, Wyo. Agrie. Exp. Stn. BulL 367.

Fosberg, M. A., and M. Hironaka.

1964. Soil properties affecting the distribution of big

and low sagebrush communities in southern Idaho.

Am. Soc, Agron. Spec. Publ. 5, p. 230-236.

Tisdale, E. W., M. Hironaka, and M. A. Fosberg.

1965. An area of pristine vegetation in Craters of the

Moon National Monument, Idaho. Ecol. 46:349-352.

—^ - ^— - M. Hironaka, and M, A. Fosberg.

1969. The sagebrush region in Idaho: a problem in

range resource management. Univ. of Idaho, Idaho

Agrie, Exp. Stn. Bull. 512, 15 p.

DESERT SHRUB

Bleak, A. T., and N. C. Frischknecht.

1965. Problems in artificial and natui^al revegetation

of the arid shadscale vegetation zone of Utah and

Nevada. J. Range Manage. 18:59-65.

Cable, Dwight R., and Fred H. Tschirley.

1961. Responses of native and introduced grasses following aerial spraying of velvet mesquite in southern Arizona. J. Range Manage. 14:155-159.

Nicho!, A. A.

1952, Natural vegetation of Arizona. Ariz. Agrie.

Exp. Stn. Tech. Bull. 127, p. 189-230.

Reynolds, Hudson G., and S. Clark Martin.

1968. Managing grass-shrub cattle ranges in the

Southwest. USDA Forest Serv., Agrie. Handb. 162.

Rosenzweig, Michael L., and Jerald Winakur.

1969. Population ecology of desert rodent communities: habitats and environmental complexity. Ecol.

50:558-572.

Schmutz, Ervin M., Dwight R. Gabel, and John J.

Warwick.

1959. Effect of shrub removal on the vegetation of a

semidesert grass-shrub range, J. of Range Manage.

12:34-37.

Turner, Raymond M., Stanley M. Alcorn, and George

Clin.

1969. Mortality of transplanted saguaro seedlings,

Ecol 50:835-844.

West, Neal E., and Kama! J. Ibrehim

1968. Soil-vegetation relationships in the shadscale

zone of southeastern Utah. Ecol. 49:445-456.

SOUTHWESTERN SHRUBSTEPPE

Cable, D. R,

1969. Comipetition in the semidesert grass-shrub types

as influenced by root systems, growth habits, and

soil moisture. Ecol. 50:27-38,

Gehlbach, F. R.

1967. Vegetation of the Guadalupe escarpment, New

Mexico-Texas. Ecol. 48:404-419.

Goebel, C.J., and C. W. Cook

1960. Effect of range condition on plant vigor, production, and nutritive value of forage, J. Range

Manage. 13:307-313.

Humphrey, R. R.

1933. The desert grassland: a history of vegetational

changes and an analysis of causes. Bot. Rev. 24:

193-252.

Jameson, D. J,

1962. Effects of burning on a galleta-black grama

range invaded by juniper. Ecol, 43:760-763.

Leithhead, H. L.

1959. Runoff in relation to range condition in the Big

Bend-Davis Mountain section of Texas. J. Range

Manage. 12:83-87.

Paulsen, H. A., and F. N. Ares.

1961. Trends in carrying capacity and vegetation on

an arid southwestern range. J. Range Manage.

14:78-83.

1962. Grazing values and management of blackgrama

and tobosa grasslands and associated shrub ranges

of the Southwest. USDA Forest Serv., Tech. Bull.

1270,56 p.

Potter, L. D., and J. C. Krenetsky.

1967. Plant succession with released grazing on New

Mexico range lands. J. Range Manage. 20:145-151.

Thomas^ G. W., and V. A. Young.

1964. Relation of soils, rainfall, and grazing management to vegetation—western Edwards Plateau of

Texas. Texas Agrie, and Mech. Univ., Texas Agrie.

Exp. Stn. Bull. 786.

Whittaker, R. H., and W, A. Niering.

1965, Vegetation of the Santa Catalina Mountains,

Arizona: a gradient analysis of the south slope,

Ecol. 46:429-452.

CHAPARRAL-MOUNTAIN SHRUB

Same as southwestern shrubsteppe.

PINYON-JUNIPER

Same as southwestern shrubsteppe.

MOUNTAIN GRASSLANDS

Costello, D. F.

1954. Vegetation zones in Colorado. In Introduction to

The manual of the higher plants of Colorado, by

H. D. Harrington. Sage Book Co., Denver, Colo.

Daubenmire, R. P.

1942. An ecological study of the vegetation of southeastern Washington and adjacent Idaho. EcoL

Monogr. 12(Jan.) :53-79.

Hurd, Richard M.

1961. Grassland vegetation in the Bighorn Mountains,

Wyoming. Ecol. 42(3) :459-467.

Johnson, W.M.

1962. Vegetation of high altitude ranges in Wyoming

as related to use by game and domestic sheep. Univ.

of Wyo., Agrie. Exp. Stn. Bull. 387.

Mueggler, W. F., and C. A. Harris. :

1969. Some soil and vegetation characteristics of

mountain grasslands in central Idaho. Ecol. 50(4) :

671-678.

Pickford, G. D., and E. H. Reid.

1942. Basis for Judging subalpine grassland ranges

of Oregon and Washington. USDA, Circ. 655, 37 p.

64
strickler, Gerald S.

1961. Vegetation and soil condition changes on subalpine grassland in eastern Oregon. USDA Forest

Serv. Res. Pap. PNW-40, 46 p. Pac. Northwest

Forest and Range Exp. Stn., Portland, Oreg.

MOUNTAIN MEADOWS

Crane, B. K.

1950. Condition and grazing capacity of wet meadows

on the east slope of the Sierra-Nevada Mountains.

J. of Range Manage. 3(4) :303-307.

Pickford, G, D., and E. H, Reid.

1942. Guides to determine range condition and proper

use of mountain meadows in eastern Oregon. USDA

Forest Serv. Range Res. Rep. PNW-3, 19 p. Pac.

Northwest Forest and Range Exp. Stn., Portland,

Oreg.

Saunderson, H. R.

1967. Herbage production on high Sierra-Nevada

meadows. J. Range Manage. 20(4) :255-256.

DESERT GRASSLANDS

Same as southwestern shrubsteppe.

ANNUAL GRASSLANDS

Bentley, J. R., L. R, Green, and K. A. Wagnon.

1958. Herbage production and grazing capacity on

annual-plant range pastures fertilized with sulphur.

J. Range Manage. 11:133-140.

. and M. W. Talbot.

1951. Efficient use of annual plants on cattle ranges

in the California foothills. USDA, Circ. 870, 52 p.

Burcham, L. T,

1956. Historical backgrounds of rangeland use in California, J. Range Manage. 9:81-86.

Conrad, C, E., E. J. Woolfolk, and D. A. Duncan.

1966, Fertilization and management implications on

California annual-plant range. J. Range Manage.

19:20-26.

Duncan, D. A., and L. 0. Hylton, Jr.

1970. Eifects of fertilization on quality of range

forage. In Range and wildlife habitat evaluation—

a research symposium, p. 57-62. USDA, Misc.

Publ. 1147.

Green, L. R., K. A. Wagnon, and J. R. Bentley.

1958. Diet and grazing habits of steers on foothill

range fertilized with sulphur. J. Range Manage.

11:221-227.

Heady, H. F.

1958. Changes in a California annual plant community

type. Ecol. 39:402-416.

1961. Continuous vs. specialized grazing systems: a

review and application of the California annual

type. J. Range Manage. 14:182-193.

1964. Palatability of herbage and animal preference.

J. Range Manage. 17:76-82.

Jones, M. B.

1960. Response of annual range to urea applied at

various dates. J. Range Manage. 13:188-192.

McNaughton, S. J.

1968. Structure and function in California grasslands.

EcoL 49:962-972.

Naveh, Z.

1967. Mediterranean ecosystems and vegetative types

in California and Israel. Ecol. 48:445-459.

Ratliff, R. A., and H. F. Heady.

1962. Seasonal changes in herbage weight in an

annual grass community. J. Range Manage. 15:

146-149.

Reppert, J. N., M. J. Morris, and C. A, Graham.

1962. Estimation of herbage on California annualtype range. J. Range Manage. 15:318-323.

Stoddart, L. A., and A. D. Smith.

1955. Range management. 433 p. McGraw-Hill Book

Co., Inc., New York.

Wagnon, K. A., H. R. Guilbert, and E. H. Hart.

1959. Beef cattle investigations on the San Joaquin

Experimental Range. Calif. Agrie, Exp. Stn. Bull.

765, 71 p.

Walker, C. F., and W. A. Williams.

1963. Responses of annual-type range vegetation to

sulphur-fertilization. J. Range Manage. 16:64-69.

WilHam, W. A., C. M. McKell, and J. N, Reppert.

1964. Sulphur fertilization of an annual-range soil

during years of below normal rainfall. J. Range

Manage. 17:1-5.

Wood, W. E.

1950. Rangeland use in California. J. Range Manage.

50:204-212.

ALPINE

Johnson, P. L., and W. D. Billings.

1962. The alpine vegetation of the Beartooth Plateau

in relation to cryopedogenic processes and patterns.

EcoL Monogr, 32:105-135.

Paulsen, H. A., Jr.

1960. Plant cover and foliage use of alpine sheep

ranges in the Central Rocky Mountains. Iowa State

Coll., J. Sei. 34:731-748.

Pond, P. W., and D. R. Smith.

1971. Ecology and management of subalpine ranges

on the Big Horn Mountains of Wyoming. Univ. of

Wyo., Wyo. Agrie. Exp. Stn., Res. J. 53, 24 p.

Smith, D. R.

1969. Vegetation, soils, and their interrelationships at

timberline in the Medicine Bow Mountains, Wyoming, Univ. of Wyo., Wyo. Agrie. Exp. Stn., Sei.

Monogr. 17,13 p.

U.S. Department of Agriculture, Forest Service.

1958. Timber resources for America's future. USDA

Forest Serv., Forest Resour. Rep. 14, 713 p.

WESTERN FOREST

DOUGLAS-FIR

Daniel, T. W., and M. E. Ensminger.

1945. Grazing on cutover lands of western Washington, State Coll. of Wash., Wash. Agrie. Exp. Stn.,

Pop. Bull. 179,

Franklin, J. F., and C. T. Dyrness.

1969. Vegetation of Oregon and Washington, US'^A

Forest Serv. Res. Pap. PNW-80, rev. 1973. P. \

Northwest Forest and Range, Exp. Stn., Portlano,

Oreg.

and C. T. Dyrness.

1973. Natural vegetation of Oregon and Washington.

USDA Forest Serv. Gen. Tech. Rep. PNW-8, 417 p.

Pac. Northwest Forest and Range Exp. Stn., Portland, Oreg.

Reid, E. H., L. A. Isaac, and G. D. Pickford

1938. Plant succession on a cutover, burned, and

grazing Douglas fir area, USDA Forest Serv. Res.

Note PNW-26. Pac. Northwest Forest and Range

Exp. Stn., Portland, Oreg.

PONDEROSA PINE

Costello, D. F., and H. E, Schwann.

1946, Conditions and trends on ponderosa pine ranges

in Colorado. USDA Forest Serv. Rocky Mt. Forest

and Range Exp. Stn., Fort Collins, Colo., and Rocky

Mt. Reg. Off., Denver, Colo.

65
Garrison, G. A.

1965. Changing conditions in northwest forested

ranges, Proc. See. Am. Foresters [Denver, Colo.]

1964:67-68.

1969. Challenge of forest grazing in Pacific Northwest. In Abstracts of papers at 22nd annual meeting, Amer. Soc. of Eange Manage. [Calgary, Alberta, 1969]. p. 31. Anier. Soc. of Range Manage.

Pearson, H. A., and D. A. Jameson.

1967. Relationship between timber and cattle production on ponderosa pine range : the Wild Bill Ra,nge.

USDA Forest Serv. Rocky Mt. Forest and Range

Exp, Stn.

Pickford, G. D., and E. H, Reid.

1948. Forage utilization on summer cattle ranges in

eastern Oregon. USDA, Circ. 796, 27 p.

Reid, E.H.

1948. Forest grazing in the Pacific Northwest. Proc.

Soc. Am. Foresters 1947:296-302.

1964. Forage production in ponderosa pine forests.

Proc. Soc. Am. Foresters [Denver, Colo.] 1964.

Rummell, R. S.

1951. Some effects of livestock grazing on ponderosa

pine forest and range in central Washington. Ecol.

32(4): 594-607.

WESTERN WHITE PINE

Same as Douglas-fir and ponderosa pine.

FIR-SPRUCE

Same as Douglas-fir and ponderosa pine.

HEMLOCK-SITKA SPRUCE

Franklin, J, F., and C. T. Dyrness.

1969. Vegetation of Oregon and Washington. USDA

Forest Serv. Res. Pap. PNW-80, rev. 1973. Pac.

Northwest Forest and Range Exp. Stn., Portland,

Oreg.

LARCH

Same as Douglas-fir and ponderosa pine.

LODGEPOLE PINE

Same as ponderosa pine.

WESTERN HARDWOODS

Same as annual grasslands.

GREAT PLAINS

SHINNERY

Allred, B. W.

1949. Distribution and control of several woody

plants in Texas and Oklahoma. J. Range Manage.

2:15-29.

Lotspeich, F. P., and M. E. Everhart.

1962. Climate and vegetation as soil forming factors

on the Llano Estacado. J. Range Manage. 15:134-

141.

Stoddart, L. A., and A. D. Smith.

1955. Range management. 433 p. McGraw-Hill Book

Co., Inc., New York.

Weaver, J. E., and F. E. Clements,

1938. Plant ecology. 601 p. McGraw-Hill Book Co.,

Inc., New York.

TEXAS SAVANNA

Box, T. W.

1960. Herbage production in four range plant communities in south Texas. J. Range Manage. 13:72-

76.

1961. Relationships between plants and soils of four

communities in south Texas. Ecol. 42:794-810.

Fanning, C. D., C. M. Thompson, and Dean Isaacs.

1965, Properties of saline range soils of the Rio

Grande Plain. J. Range Manage. 18:190-193.

Johnston, M.

1963. Past and present grasslands of southern Texas

and N.E. Mexico. Ecol. 44:456-466.

McMahan, C. A., and C. W. Ramsey.

1965. Response of deer and livestock to controlled

grazing in central Texas. J. Range Manage. 18:1-7.

StoddartVL. A., and A. D. Smith.

1955. Range management. 433 p. McGraw-Hill Book

Co., Inc., New York.

Thomas, G. W., and V. A. Young,

1954. Relation of soils, rainfall, and grazing management to vegetation—western Edwards Plateau of

Texas» Texas Agrie, and Mech. Univ., Texas Agrie.

Exp. Stn. Bull. 786.

Thorp, B.C.

1926. Structure of Texas vegetation east of the 98th

meridian, Univ. of Texas Bull, 2606.

PLAINS GRASSLANDS

Bjugstad, A. J., and W. C. Whitman.

1970. Significance of reduced plant vigor in relation

to range condition. J. Range Manage. 23:181-184.

Holscher, C. E., and E. J. Woolfolk.

1953. Forage utilization by cattle on northern Great

Plains ranges. USDA, Circ. 918,

Houston, W.R.

1961. Some interrelations of sagebrush, soils, and

grazing intensity in the northern Great Plains. Ecol.

42:31-38.

Larson, P., and W. Whitman.

1942. A comparison of used and unused grassland

mesas in the Badlands of South Dakota. Ecol. 23:

438-445.

Reed, M. J., and R. A. Peterson.

1961. Vegetation, soils, and cattle responses to stocking and grazing on northern Great Plains ranges.

USDA, Tech. Bull. 1252, 79 p.

Smoliak, S.

1956. Influence of climatic conditions on forage production of shortgrass rangeland. J. Range Manage.

9:89-91.

Weaver, J. E., and F. E. Clements.

1938. Plant ecology. 601 p. McGrav/-Hill Book Co.,

Inc., New York.

PRAIRIE

Aikman, J. M.

1955. Burning in the management of prairie in Iowa.

Iowa Acad. Sei. Proc. 62:53-62.

Buttery, R. F.

1960. Grazed glades can grow good grass. J. Range

Manage. 13:234-235.

Costello, D. F.

1969. The prairie world, 242 p. Crowell Co., New

York.

Ehrenreich, J. H.

1959. Effect of burning and clipping on growth of

native prairie in Iowa. J. Range Manage, 12:133-

137.

:^ and J. M. Aikman,

1963. An ecological study of the effect of certain management practices on native prairie in Iowa. Ecol,

Monogr. 33:113-130.

Hopkins, H.H.

1951. Ecology of the native vegetation of the loess

hills in central Nebraska. Ecol Monogr. 21:125-147.

Hulbert, T.

1969. Fire and litter effects in undisturbed bluestem

in Kansas. Ecol. 50:874-877.

Kelting,R.W.

1954. Effects of moderate grazing on the composition

and plant production of a native tall-grass prairie

in central Oklahoma. Ecol. 35:200-207.

m
Kucera, CL., and J. H. Ehrenreich.

1962. Some effects of annual burning on central Missouri prairie. Ecol. 43:334-336.

and S. C. Martin.

1957. Vegetation and soil relationships in the glade

region of the southwestern Missouri Ozarks. Ecol.

38:285-291.

Martin^ S. C, and J. S. Crosby.

1955. Burning and grazing on glade range in Missouri.

USDA Forest Serv. Tech. Pap. CS-147. Cent. States

Forest Exp. Stn., Columbus, Ohio.

Porter, C. L.

1966. An analysis of variation between upland and

lowland switchgrass, Panicum virgatum L., in central Oklahoma. Ecol. 47:980-992.

Vogel, W. G., and A. J, Bjugstad.

1968. Effects of clipping on yield and tillering of

little bluestem, big bluestem, and Indiangrass. J.

Range Manage. 21:136-140.

Weaver, J. E., and F. E. Clements.

1938. Plant ecology. 601 p. McGraw-Hill Book Co.,

Inc., New York.

EASTERN FOREST

WHITE-RED-JACK PINE

Braun, E. L.

1950. Deciduous forests of eastern North America.

Blakiston Co., Philadelphia, Pa.

SPRUCE-FIR

Same as white-red-jack pine.

LONGLEAF-SLASH PINE

American Society for Range Management, Southern

Section.

1955. Range resources of the South. Univ. of Ga., Ga.

Agrie. Exp. Stn. Bull. N. S. 9, 31 p.

Duvall, V. L., and Norwin E. Linnartz.

1967. Influences of grazing and ñre on vegetation

and soil of longleaf pine-bluestem range. J. Range

Manage. 20:241-247.

and L. B. Whitaker.

1964. Rotation burning: a forage management system for longleaf pine bluestem ranges. J. Range

Manage. 17:322-326.

Gansner, D. A.

1965. Missouri forests. USDA Forest Serv. Resour.

Bull. CS-2. Cent. States Forest Exp. Stn., Columbus, Ohio.

Grelen, H. E., and V. L. Duvall.

1946. Common plants of the longleaf pine-bluestem

range. USDA Forest Serv. Res. Pap. SO-23, 96 p.

South. Forest Exp. Stn., New Orleans, La.

and E. A. Epps, Jr.

1967. Season of burning affects herbage quality and

yield on pine-bluestem range. J. Range Manage.

20:31-33.

Hottel, J. B., and A. P. Arnold.

1965. Crop, pasture, timber, and livestock enterprises

for the Boston Mountain and Ozark Highland areas

of Arkansas. Univ. of Arkansas, Agrie. Exp. Stn.

Rep. Ser. 135.

Nelson, T. C, and W. M. Zillgitt.

1969. A forest atlas of the South. 27 p. USDA Forest

Serv. South. Forest Exp. Stn., New Orleans, La.

Pearson, H. A., L. B. Whitaker, and V. L. Duvall.

1971. Slash pine regeneration and regulated grazing.

^ J. Forestry 69:744-746.

Society of American Foresters.

1954. Forest cover types of North America. 67 p.

Soc. of Am. Foresters, Wash., D. C.

Sternitzke, H. S.

1960. Arkansas forests. 58 p. USDA Forest Serv.

South. Forest Exp. Stn., New Orleans, La.

LOBLOLLY-SHORTLEAF PINE

Duvall, V. L., and Norwin E. Linnartz.

1967. Influences of grazing and fire on vegetation

and soil of longleaf pine-bluestem range. J. Range

Manage. 20:241-247.

and L. B. Whitaker.

1964. Rotation burning: a forage management system for longleaf pine-bluestem ranges. J. Range

Manage. 17:322-326.

Grelen, H. E., and V. L. Duvall.

1946. Common plants of the longleaf pine-bluestem

range. USDA Forest Serv. Res. Pap. SO-23, 96 p.

South. Forest Exp. Stn., New Orleans, La.

and E. A. Epps, Jr.

1967. Season of burning affects herbage quality and

yield on pine-bluestem range. J. Range Manage.

20:31-33.

Pearson, H. A., L. B. Whitaker, and V. L. Duvall.

1971. Slash pine regeneration and regulated grazing.

J. Forestry 69:744-746.

OAK-PINE

Same as loblolly-shortleaf pine.

OAK-HICKORY

Bazzaz, F. A.

1968. Succession on abandoned fields in the Shav/nee

Hills, southern Illinois. Ecol. 49:924-936.

Bjugstad, A. J., and H. S. Crawford.

1967. Cattle in the woods or woods in the pasture.

USDA Forest Serv. Res. Note NC-23. North Cent.

Forest Exp. Stn., St. Paul, Minn.

. and A. V. Dalrymple.

1968. Behavior of beef heifers on Ozark ranges. Univ.

of Mo., Mo. Agr. Exp. Stn. Bull. 870.

. D. A. Murphy, and H. S. Crawford.

1968. Poor returns from Ozark woodland grazing.

USDA Forest Serv. Res. Note NC-60. North Cent.

Forest Exp. Stn., St. Paul, Minn.

Caplenor, D.

1968. Forest composition on loessal and non-loessal

soils in west-central Mississippi. Ecol. 49:322-331.

Clarkson, R. B.

1966. The vascular flora of the Monongahela National

Forest, West Virginia. Castanea 31:1-119.

Crawford, H. S., and A. J. Bjugstad.

1967. Establishing grass range in the southwestern

Missouri Ozarks. USDA Forest Serv. Res. Note

NC-22. North Cent. Forest Exp. Stn., St. Paul,

Minn.

— and R. G. Leonard.

1965. The Sylamon deer study. Proc. 17th Annu.

Conf., Southeast. Assoc. Game and Fish Comm., p.

9-13.

Davis, A. M.

1967. Rangeland development through brush control

in the Arkansas Ozarks. Univ. of Arkansas, Agrie.

Exp. Stn. Bull. 726.

Ehrenreich, J. H., and J. S. Crosby.

1960. Forage production on sprayed and burned areas

in the Missouri Ozarks. J. Range Manage. 13:68-69.

and J. S. Crosby.

1960. Herbage production is related to hardwood

crown cover. J. Forestry 58:564-565.

. and R. A. Ralston.

1968. Forage and timber production alternating on

shallow soils in the Ozarks. Proc. Soc. Am. Foresters [Boston, Mass.], p. 80-83.

Halls, L. K., and H. S. Crawford.

1960. Deer-forest habitat relationships in North Arkansas. J. Wildl. Manage. 24:387-395.

and H. S. Crawford.

1965. Vegetation response to an Ozark woodland

spraying. J. Range Manage. 18:338-340.

67
. R A. Eead, and H. S. Crawford.

1960. Forage and ground-cover conditions in nnmanaged Ozark forests. South. Forest Ees. 1:1-16.

Hottel, J. B., and A. F. Arnold.

1965. Crop, pasture, timber, and livestock enterprises

for the Boston Mountain and Ozark Highland areas

of Arkansas. Univ. of Arkansas, Agrie. Exp. Stn.

Rep, Ser. 135.

Hough, A, F.

1965. A twenty-year record of understory vegetation

changes in a virgin Pennsylvania forest. Ecol. 46:

370-373.

Jones, A. S., and E. G. Patton.

1966. Forest, -'prairie," and soils in the Black Belt

of Sumter County, Alabama, in 1832. Ecol. 47:75-

80.

Martin, S. C.

1955. The place of range livestock in the Missouri

Ozarks. J. Range Manage. 8:105-111.

Murphy, D. A., and J. H. Ehrenreich.

1965. Effects of timber harvest and stand improvement on forage production. J. Wildl. Manage. 29:

734-739.

Pearson, P. R.

1962. Increasing importance of sugar maple on two

calcareous formations in New Jersey, Ecol. 43:711-

718.

Ray, H. C, and M. Lawson.

1955. Site characteristics as a guide to forest and

grazing use in the Ozarks. J. Range Manage. 8:

69-'73.

Read, R. A.

1951. Woodland forage in the Arkansas Ozarks. J.

Range Manage. 4:391-396.

Sherman, R. W.

1967. Economics of sawtimber production in Appalachia, Ohio. Ohio Agrie. Res. and Dev, Cent.

(Wooster, Ohio), Res. Circ. 152.

Society of American Foresters

1954. Forest cover types of North America. 67 p.

Soc. Am. Foresters, Wash., D. C.

Sternitzke, H. S.

1967. East Texas post oak region. USDA Forest Serv.

Resour. Bulk SO-11. South. Forest Exp. Stn., New

Orleans, La.

Whittaker, R. H.

1962. Net production relations of shrubs in the Great

Smoky Mountains. Ecol. 43 :S57-377.

1966. Forest dimensions and productions in the Great

Smoky Mountains. Ecol. 47:103-121.

OAK-GUM-CYPRESS

Beals, E. W., and J.B. Cope.

1964. Vegetation and soils in an eastern Indiana

woods. Ecol. 45:777-792.

Blomquist, H. L.

1940. Introduction to the grasses of North Carolina.

8 p. [Mimeographed] Duke Univ., Durham, N.C,

Caplenor, D.

1968. Forest eomposition on loessal and non-loessal

soils in west-central Mississippi. Ecol. 49:322-331.

Golley, F., H. T. Odum, and R. F. Wilson.

1962. The structure and metabolism of a Puerto

Rican red mangrove forest in May. Ecol. 43:9-19;

Halls,L.K.

1970. Growing deer food amidst southern timber. J.

Range Manage. 23:213-215.

Lemon, P. C.

1945. Wood as a substratum for perennial plants in

the Southeast. Am. Midi. Nat. 34:744-749.

Porter, C. L., Jr.

1967. Composition and productivity of a subtropical

prairie. EcoL 48:937-942.

Williams, R. E,,J.T. Gassady, L. K. Halls, and E. J.

Woolfoik.

1955. Range resources of the South. Univ. of Ga., Ga.

Agrie. Exp. Stn. Bull. N.S.-9, 31 p. [In cooperation

with South. Sect., Am. Soc. for Range Manage.]

ELM-ASH-COTTONWOOD

Beals, E. W'., and J. B. Cope.

1964. Vegetation and soils in an eastern Indiana

woods. Ecol. 45:777-792.

Ganser, D. A.

1965. Missouri forests. USDA Forest Serv. Resour.

Bull. CS-2. Cent. States Forest Exp. Stn., Columbus, Ohio.

Society of American Foresters.

1954. Forest cover types of North America. 67 p. Soc.

of Am. Foresters, Wash., D.C.

MAPLE-BEECH-BIRCH

Same as white-red-jack pine.

ASPEN-BIRCH

Same as white-red-jack pine.

WET GRASSLANDS

Halls, L.K.

1957. Grazing capacity of wiregrass-pine ranges of

Georgia. J. Range Manage. 10:1-5.

Porter, C. L.

1967. Composition and productivity of a subtropical

prairie. EcoL 48:937-942.

Rlimmell, R. S.

1957. Beef cattle production and range practices in

south Florida. J. Range Manage. 10:71-78.

Shelford, V. E.

1963. The ecology of North America. 610 p. Univ. of

111. Press, Urbana, 111.

Shiflet,:T. A.

1963. A conservation program for grazing woodlands

in the Southeast. J. Range Manage. 16:18-21.

Southwell, B. L., and R. H. Hughes.

1965. Beef cattle management practices for wiregrass-pine ranges of Georgia. Univ. of Ga., Ga.

Agrie. Exp. Stn. Bull N.S. 129.

Williams, R.E.

1958. Practical range management in the South. J.

Range Manage. 11:270-274.

—— J. T. Cassady, L. K. Halls, and E. J.

Woolfolk.

1955. Range resources of the South. Univ. of Ga.,

Ga. Agrie. Exp. Stn. Bull. N.S. 9, 31 p. [In Cooperation with South. Sect., Am. Soc. for Range Manage.]

Yarlett,L. L.

1965. Control of saw palmetto and recovery of native

grasses. J. Range Manage. 18:344-345.

— - - and R. D. Roush.

1970. Creeping bluestem (Andropogón stolonifer

(Nash) Hitchc.).J. Range Manage. 23:117-122.

•t^ UJ. GOVERNMENT PRINTING OFFICE : 1977-0-552-756

6B
UNITED STATES DEPARTMENT OF AGRICULTURE FOREST SERVICE