Forested Communities of the Upper

Montane in the Central and Southern

Sierra Nevada

United States

Department

of Agriculture

Forest Service

Pacific Southwest

Research Station

General Technical Report

PSW-GTR-169

Donald A. Potter
Abstract

Potter, Donald A. 1998. Forested communities of the upper montane in the central and southern

Sierra Nevada. Gen. Tech. Rep. PSW-GTR-169. Albany, CA: Pacific Southwest Research

Station, Forest Service, U.S. Department of Agriculture; 319 p.

Upper montane forests in the central and southern Sierra Nevada of California were classified into

26 plant associations by using information collected from 0.1-acre circular plots. Within this region,

the forested environment including the physiographic setting, geology, soils, and vegetation is

described in detail. A simulation model is presented for this portion of the Sierra Nevada that refines

discussions of climate, and disturbance regimes are described to illustrate the interaction between

these features of the environment and vegetation in the study area. In the classification, plant

associations are differentiated by floristic composition, environmental setting, and measurements

of productivity. Differences in elevation, aspect, topographic setting, and soil properties generally

distinguish each plant association described. A detailed description is presented for each plant

association, including a discussion of the distribution, environment, vegetation, soils, productivity,

coarse woody debris, range, wildlife, and management recommendations. A complete species list

and tables for cross referencing specific characteristics of each association are provided.

Retrieval Terms: Vegetation classification, ecological classification, potential natural vegetation,

plant association, red fir (Abies magnifica), white fir (Abies concolor), sugar pine (Pinus

lambertiana), Jeffrey pine (Pinus Jeffreyii), lodgepole pine (Pinus contorta), mountain hemlock

(Tsuga mertensiana), western white pine (Pinus monticola), western juniper (Juniperus

occidentalis), quaking aspen (Populus tremuloides).

Useful English/metric conversions for this classification are:

1 inch = 2.54 centimeters 1 centimeter = 0.39 inch

1 foot = 0.30 meters 1 meter = 3.28 feet

1 square foot = 0.09 square meters 1 square meter = 10.76 square feet

1 cubic foot = 0.03 cubic meters 1 cubic meter = 35.31 cubic feet

1 acre = 0.41 hectares 1 hectare = 2.47 acres

The Author

Donald A. Potter is Province Ecologist for the Sequoia, Sierra, and Stanislaus National Forests,

Pacific Southwest Region, USDA Forest Service. He is located on the Stanislaus National Forest,

19777 Greenley Road, Sonora, California 95370.

Publisher:

Albany, California

Mailing address:

PO Box 245, Berkeley CA

94701-0245

(510) 559-6300

http://www.psw.fs.fed.us

September 1998

Pacific Southwest Research Station

Forest Service

U.S. Department of Agriculture

Acknowledgments

No work of this size and scope could have been completed without the assistance of many people.

Specialists in ecology, botany, genetics, silviculture, soil science, geology, hydrology, wildlife

biology, range conservation, and fuels management enthusiastically offered their observations,

insights, and advice from the field. It was a genuine pleasure to work with and learn from all of them.

A collective round of thanks is truly offered to all. I would also like to thank Michael Barbour,

Edward Stone, and Alan Taylor for reviewing the manuscript, and special thanks go to the following

for their exemplary and dedicated efforts in the field and office: Botanists—John Rivera, Kathy

Burnett, Susan Urie, and Tom Beck; Soil Scientists—Ben Smith, Alex Janicki, Randy Westmoreland,

Ken Roberts, Calvin Pratt, Elise Pendall, and Wayne Verrill; Field Technicians—Wyrita Myster,

and Charles Whitehead; Data Entry and Office Support—Thelma Joslin. Final drafts of the

manuscript were edited by Laurie J. Dunn, and the layout produced by Kathy Stewart, both of the

Pacific Southwest Research Station, USDA Forest Service, Albany, California.
Forested Communities of the Upper

Montane in the Central and Southern

Sierra Nevada

Donald A. Potter

Pacific Southwest

Research Station

USDA Forest Service

General Technical

Report

PSW-GTR-169

September 1998

Contents:

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Classification Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Potential Natural Community. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Evolutionary Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Classification Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

The Forest Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Physiographic Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Disturbance Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Data Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

General Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

North-South Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

East-West Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Ordination of Trees and Shrubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Using the Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Use of the Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Key to Plant Associations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Association Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Bolander’s Locoweed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Quaking Aspen/Mountain Pennyroyal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Quaking Aspen/California Corn Lily . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Western Juniper/Sagebrush . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Western Juniper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Red Fir/Mountain Mule Ears . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Mountain Hemlock//Steep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Mountain Hemlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Red Fir-Western White Pine/Pinemat Manzanita . . . . . . . . . . . . . . . . . . . . . . . 121

Red Fir-Western White Pine/Sierra Chinquapin . . . . . . . . . . . . . . . . . . . . . . . . 129

Red Fir-Western White Pine-Lodgepole Pine . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Red Fir-Western White Pine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

White Fir-Sugar Pine-Red Fir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Jeffrey Pine/Huckleberry Oak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

Jeffrey Pine/Greenleaf Manzanita-Snowbrush . . . . . . . . . . . . . . . . . . . . . . . . . 169

Jeffrey Pine/Mountain Whitethorn-Sagebrush . . . . . . . . . . . . . . . . . . . . . . . . . 177
USDA Forest Service Gen. Tech. Rep. PSW-GTR-169. 1998.

Red Fir-White Fir-Jeffrey Pine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

Jeffrey Pine-Red Fir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

Lodgepole Pine/Sagebrush . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

Lodgepole Pine/Gray’s Lovage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

Lodgepole Pine//Woodlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

Lodgepole Pine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

Red Fir-Lodgepole Pine/White Flowered Hawkweed . . . . . . . . . . . . . . . . . . . 233

Red Fir-White Fir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

Red Fir/Pinemat Manzanita . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

Red Fir. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

Appendices

A-Classification Hierarchy of Plant Associations . . . . . . . . . . . . . . . . . . . . . . . 265

B-Soil Taxonomy by Plant Association . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

C-Variables Used in the Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

D-Autecological Relationships of Selected Plants . . . . . . . . . . . . . . . . . . . . . . 274

E-Environmental Summary by Plant Association . . . . . . . . . . . . . . . . . . . . . . . 289

F-Vegetation Summary by Plant Association . . . . . . . . . . . . . . . . . . . . . . . . . . 290

G-Soil Summary by Plant Association . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291

H-Productivity Summary by Plant Association. . . . . . . . . . . . . . . . . . . . . . . . . 292

I-Common Plants of the Upper Montane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307

Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311

ii
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PSW-GTR-169

General Technical ReportResearch StationPacific SouthwestForest Serviceof AgricultureDepartmentUnited States

the Central and Southern Sierra NevadaForested Communities of the Upper Montane in
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 1

Introduction

Ecological classifications generally describe several elements of naturalresource information such as vegetation, soils, geology, and physiography.

They are designed to provide users with site specific information on species

composition, environmental setting, productivity, and expected responses to

management. Such classifications are not new. Systems such as habitat types

(Daubenmire 1952) and community types (Hall 1973) have been used throughout

the west since the early 1950’s; however, none of these contain information

specific to California ecosystems or Sierra Nevada forested plant communities in

particular (Wellner 1987). Several descriptions of California vegetation also

include broad-based discussions of plant communities in upper montane forests

(Bailey 1995, Eyre 1980, Hickman 1993, Holland 1986, Kuchler 1964, Mayer and

Laudenslayer 1988, McNab and Avers 1994, Munz and Keck 1959, Rundle and

others 1988, U.S. Department of Agriculture 1981). However, these descriptions

generally do not recognize the variety of plant communities that are encountered

in the upper montane, and they do not provide detailed discussions of

composition, structure, environmental setting, productivity, or management

specific to those communities.

Classifications attempt to group similar plant communities and distinguish

them from dissimilar ones. The process of classifying is usually arbitrary at some

point, because often the distinctions between classified units are not sharp. This

is particularly true in natural systems. Thus, classifications remain tentative and

subject to change as hypotheses are tested and knowledge obtained. This study is

an initial effort to classify upper montane forests in the central and southern

Sierra Nevada with the following objectives:

• To identify and describe the major plant communities within the upper

montane forests of the central and southern Sierra Nevada.

• To provide an understanding of the relationships between vegetation

and environment in these communities.

• To develop a dynamic classification scheme that incorporates current

theories about the role of disturbance in succession.

• To provide interpretations of the ecological relationships among and

between plant communities that will guide vegetation management of

these same communities.

• To provide a framework for describing research results and to serve as

a basis for defining future research needs.

This report integrates information about the floristic composition of forested

stands with physical site characteristics to provide an ecological classification of

upper montane forested ecosystems in the central and southern Sierra Nevada of

California and western Nevada.

Study Area

The project area encompassed the upper elevations of the Sierra Nevada between

Lake Tahoe in Eldorado County and Lake Isabella in Kern County (fig. 1). It

covered both westside and eastside slopes of the range. On the north the

boundary followed a line between the American River and McKinney Creek on

the west side of Lake Tahoe and Highway 50 at Spooner Summit on the eastside.

Latitudes in the north were about 39°7'. The southern boundary was a line that
2 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

crossed Sunday Peak and Little Cannell Meadow on the Sequoia National Forest

at latitude 35°45'. Longitudes ranged between 120°25' on the west and 118°9’on

the east.

These forests are generally dominated by red fir (Abies magnifica), and this

species was used in the classification to distinguish upper montane forests. On the

western slopes of the range, the study commenced at elevations where red fir was

first encountered. It continued upward until red fir was no longer a component of

the stands. Across the crest, it commenced as red fir was again encountered and

progressed down the eastern slopes to elevations at which red fir was no longer

present. In the north, red fir was first encountered in drainages as low as 5,900 feet

on the westside and 7,000 feet on the eastside. In the south, lower elevations

ranged between 6,700 feet on the west and 8,000 feet on the east. The alpine and

subalpine zones at the Sierra Nevada crest were not covered in the classification,

nor were the mixed conifer and ponderosa pine forests at lower elevations on the

westside or the Jeffrey pine forests at lower elevations on the eastside.

Seven National Forests, two National Parks, one National Monument and

state and private lands were included within the boundaries of the study area.

The westside of the Sierra Nevada contained the Eldorado, Stanislaus, Sierra,

and Sequoia National Forests, and the Inyo, Lake Tahoe Basin Management Unit,

and Toiyabe National Forests were located on the eastside. The National Park

System was represented by Yosemite and Sequoia-Kings Canyon National Parks,

and Devil’s Postpile National Monument. Portions of Alpine, Amador, Calaveras,

Eldorado, Fresno, Inyo, Kern, Madera, Mariposa, Mono, Placer, Tulare, and

Tuolumne Counties in California and Douglas County in Nevada were included

in the study area. Overall, the classification applies to nearly 3,000,000 acres in

the central and southern Sierra Nevada.

Figure 1—Upper montane study

area in relation to vegetation type

distribution in California, based on

CALVEG.

STUDY AREA

Upper Montane

UPPER MONTANE

CALVEG TYPE

Douglas Fir

Jeffrey Pine

Juniper/Pinyon-Juniper

Lodgepole Pine

Mixed Conifer

Ponderosa Pine

Redwood

Red Fir

Alpine/Subalpine

Hardwood

Other

Water
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

3

Classification Concepts

Potential Natural Community

The basic unit of classification and description is the forested plant association.

Plant associations can be viewed as potential natural plant communities that

have a definite floristic composition. Generally, they occur within uniform

habitat conditions. A potential natural plant community is defined as the plant

community that would be established if all successional sequences were

completed without human-caused disturbance under existing environmental

conditions (U.S. Department of Agriculture, Forest Service 1991). In a practical

sense, plant community structures have evolved to a dynamic equilibrium in

which individual species are regenerating, competition has stabilized, and a

different future plant community is unpredictable in the absence of major

disturbance (Driscoll and others 1984). This classification also relates the potential

natural plant community to soils and landforms typically occurring in the

landscape. The soil element is patterned after the soil taxonomy system

developed by the U.S. Department of Agriculture, Soil Conservation Service

(1975). Geology and landform elements are those described in standard

references, such as the Glossary of selected geomorphic terms for western soil

surveys compiled by the U.S. Department of Agriculture, Soil Conservation

Service (1984).

The concept of potential natural plant community differs from traditional

views of climax vegetation. Climax vegetation has commonly been considered a

stable final stage of succession. Plant communities at climax were believed to be

determined by regional climate or modification of physical environments by the

plant community (Clements 1936) or by other environmental factors such as soil or

topography. These plant communities were considered to be in equilibrium with

past and future environments, and they were considered self-replacing if disturbed.

Succession was seen as deterministic, predictable, and ending with a final, stable

climax community. The role of natural disturbances such as fire, flood, or insects

and pathogens, or the effect of human activity were not emphasized.

Long-term environmental stability is a key implication of the climax concept;

however, climatic records indicate this is not the case. Recent investigations have

also shown that succession is not deterministic. Often, several vegetation states can

exist at any point on a successional pathway. In many cases a stable, self-replacing

equilibrium state (climax) is rarely achieved because of the persistent role of

natural disturbance in shaping vegetation patterns and the long-term effects of

human activity on plant communities. Thus, the composition and structure of

plant communities are currently viewed as contingent. They depend on initial

conditions and the sequence of events that occur within and outside them.

The concept of potential natural plant community incorporates both views of

succession. The attainment of a relatively stable late-seral community is implied;

however, these communities are viewed as expressing a condition of dynamic

rather than static equilibrium. At a basic level, plant communities are shaped by

climate, soil development, and topographic setting; thus, vegetation is essentially

in balance with the biotic and abiotic factors of the site. However, disturbances at

a variety of spatial and temporal scales modify vegetation response at individual

sites, and succession is not regarded as deterministic. Disturbances can

potentially result in several existing vegetation states at any point along a

successional path. As a consequence, no stand will ever be identical in all

respects to any other. For this reason, the characteristics of potential natural

communities cannot be determined from individual stands. They emerge from

the characteristics of similar stands distributed in similar settings on the

landscape. Succession is also viewed from the perspective of a relatively short

time period, not, for example, from a geologic time scale as may be involved in
4 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

climate change. Thus, the effect of future climatic change or unknown earth

shaping disturbances are removed from consideration.

Evolutionary Perspective

From an evolutionary perspective, plant communities are viewed as responding

to Darwinian selection at the level of the individual to produce species

adaptations to unique environments. Adaptations, in general, may be

morphological or physiological, and they equip species to compete and persist in

specific habitats. Thus, differences in reproductive rates, differences in

competitive abilities through time, response to parasitism, or response to

disturbance are viewed as inherited traits that permit a species to inhabit or

dominate a particular setting.

Species also coevolve with others. The “principle” of competitive exclusion

states that if two species are ecologically identical they cannot simultaneously

inhabit the same ecological space. If two species coexist in a saturated

environment, an ecological difference may exist between them. Thus, the

ecological niche—the sum total of the adaptations of an organism to its particular

environment (Pianka 1988)—is the basis of theory about ecological diversification

and the development of complex biological communities. These concepts define

a species’ evolutionary “fitness” in a particular plant community, and they are

the bases for using similarity in both species composition and environment to

classify samples in this study. Thus, the classification is not based on floristic

differences alone, but includes differences in both species and environment as

the basis for the classification.

The role of humans in the past is acknowledged, but their future role is not

defined. Recently, additional disturbance factors have been added because of

human activities. Thus, the introduction of non-native species such as cheatgrass

(Bromus tectorum) in the 1800’s, the introduction of grazing by cattle and sheep in

the middle 1800’s, the introduction of fire suppression activities in the early

1900’s, the introduction of white pine blister rust in the 1930’s, and, more recently,

changes in air quality as a result of development and industrialization adjacent

to the Sierra Nevada, have brought changes in the vegetation that may not be

realized for substantial periods of time. Although the concept of potential natural

communities does not include future human-caused disturbance, the effects of

past human activity must be included.

Changes in community composition and structure related to these newer

disturbance elements are essentially unknown at this time. If the effects are only

slightly different from historical ones, then differences can be expected to be

relatively small, perhaps involving species abundances. On the other hand, if

they are more catastrophic or exotic in their effect on vegetation, a significant

shift perhaps involving new species complexes may occur (Denslow 1985). For

this classification, attempting to project vegetation changes in response to these

factors was simply too speculative at this time. In general, the present structure

and species composition of the late seral stands sampled was accepted as

reflecting the normal variation that occurs in the potential natural plant

communities of these sites.

Although vegetation often exists in discrete patches across the landscape,

gradual change from one vegetative community to another is a typical pattern in

these forests. This change is seen as a response to the environmental and genetic

heterogeneity between communities. Many environmental factors affect the

normal genetic variation within species to produce gradual rather than abrupt

changes in vegetation patterns. These transitions or ecotones reflect the ability of

a species to maintain a homeostatic balance across a wide range of environmental

conditions. Thus, although the associations classified here are described as

discrete entities, they are more properly viewed as lying along a gradient or
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

5

ecocline with a gradual transition from one community to the next. In some cases

an ecotone may be narrow covering a few feet, while in others it may be broad

and cover many hundreds of acres.

Classification Hierarchy

Because the classification is not designed to be hierarchical, the plant associations

described do not necessarily tier to more broadly or narrowly defined vegetation

units described by others. On the other hand, the ability to aggregate or disaggregate

vegetation patterns for broad regional or national purposes while maintaining the

integrity of the classified units can be useful. Thus, the classification framework

described by Driscoll and others (1984) is most appropriate for the plant associations

described here. This framework defines a hierarchy of potential natural plant

communities from class to formation level, and it describes series and plant

associations which occur at lower levels in the hierarchy.

The series concept has not been consistently applied in the literature on

classification work (Driscoll and others 1984, Hall 1988, Sawyer and Keeler-Wolf

1995). Series have been characterized both by individual dominant or codominant

species of the community, and by the most shade tolerant species regenerating

on the site regardless of current dominance. Neither approach is completely

compatible with the vegetation patterns of the upper montane forests. For

example, western juniper and red fir inhabit fundamentally different

environments. Western juniper is adapted to xeric conditions, and it is relatively

shade intolerant while red fir is adapted to mesic conditions, and it is more shade

tolerant. In stands with both species present, red fir may occur in the understory,

and it may provide the most overstory cover in some cases; however, the presence

of western juniper indicates that environmental conditions have shifted

indicating that it is ecologically advantaged compared to red fir. In this

classification, series are defined by overstory species dominance and

environment. Dominant or characteristic species of the upper montane are used

in conjunction with environmental differences to define series, subseries, and

plant association (appendix A). In cases where environmental differences are not

clear, dominance of cover and shade tolerance were used.

The Forest Environment

Physiographic Setting

The Sierra Nevada is the single largest mountain range in the contiguous United

States (Hill 1975). It extends more than 400 miles along a northwest-southeast

trending axis, and it varies in width between 50 and 80 miles with the widest

dimensions in the north-central portion of the range. The width decreases both

north and south from this region. The height along the crest is impressive. Thirty

peaks exceed 12,000 feet, and the range contains Mount Whitney, which at 14,494

feet, towers as the highest peak in the conterminous United States. Along the

crest, the highest peaks are found in the central portion of the range (fig. 2). From

the north, the elevation of the highest peaks gradually increases until the upper

reaches of the Kern River and Mount Whitney are encountered. Heights then

drop abruptly toward the southern extension of the range. In the north, near

Fredonyer Pass, for example, peaks seldom rise above 8,000 feet, while in the

central portion, the highest peaks are commonly above 11,000 feet, and several

exceed 14,000 feet. South of Olancha Peak, elevations drop rapidly to below 5,000

feet near Tehachapi at the southern limits of the range.

On the westside, the range rises gradually from elevations near sea level to the

crest. At right angles to the crest of the range are three transects: east of Rancho

Cordova near the northern portion of the range; east of Clovis in the central
6 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

portion; and east of Porterville at the southern end of the range (fig. 3). The

average slope on the westside is about 2° or 4 percent. This results in an average

rise in elevation of about 200 feet per mile. Elevations on the westside increase

more abruptly in the south. South of Yosemite Valley, subsidiary ridges whose

height approaches that of the main crest are found progressively closer to the

Great Valley the farther one proceeds. The western slope in a transect from

Porterville to Slate Mountain, for example, is nearly 4° or 7 percent. This results in

a rise of nearly 360 feet per mile and typifies the area south of the Kings River.

Such a regional change in shape suggests a fundamental difference in the pattern

of orogeny. Thus, the northern part of the range is a tilted block; whereas the

southern part is similar to a block that has been bodily uplifted (Christensen 1966).

From the crest, the abrupt drop on the eastern side of the Sierra Nevada is

well known, and changes in elevation are dramatic. Slopes average 9° or 16

percent. This equates to an elevation gain of nearly 850 feet per mile. The crest

drops from over 14,000 feet to elevations below 4,000 feet within 10 miles along a

transect across the southern portion of the range near Lone Pine. Even in the

north the relief is exceptional. Thus, within 7 miles, slopes drop from over 13,000

feet at Mount Dana to 6,700 feet at Lee Vining, and the drop from Freel Peak to

Highway 88 near Lake Tahoe is nearly 6,400 feet within 6 miles. Elevation (feet)

Distance (miles)

Fredonyer Pass

Castle Peak

Highland Peak

Mt Dana

Mt Whitney

Sherman Peak

Tehachapi

15,000

14,000

13,000

12,000

11,000

10,000

9,000

8,000

7,000

6,000

5,000

4,000

0 100 200 300 400

Figure 2—North to south transect

along the crest of the Sierra Nevada

showing the heights of the tallest

peaks.

Figure 3—Three transects from

west to east across the Sierra Nevada

showing change in elevation with

distance.

Elevation (feet)

Distance (miles)

Rancho

Cordova

Merced

Porterville

12,000

8,000

4,000

0

20

40

60

80

100
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

7

Except for the Kern River, which runs almost due south, major rivers flow

generally northeast-southwest at right angles to the axis of the range. These river

systems have all cut major canyons into the underlying rocks. The American,

Cosumnes, Mokelumne, Stanislaus, Tuolumne, Merced, San Joaquin, Kings, and

Kaweah rivers on the westside have all incised canyons several thousand feet

deep into the range, and the drop into the Kings River from the top of Spanish

Mountain is over 7,000 feet, one of the longest continuous mountain slopes in the

United States. River systems on the eastside are less abundant and substantially

shorter than those on the west. Nevertheless, rivers such as the Truckee and

Walker and lesser drainages such as Robinson, Green, Lundy, Lee Vining, Hilton,

and Rock Creek have all incised the range to significant depths. Tributaries to

these drainages on both sides of the range feed into them in a dendritic pattern

and further dissect the landscape. Thus, on a local scale, relief is substantial and

topography complex.

Climate

Generally, climate in the Sierra Nevada is dynamic and always changing. Since the

formation of the range, worldwide climate has varied in response to external forces

that are based on the dynamics of the solar system and structures of the earth.

Currently, the climate of North America is positioned in a warm interglacial

period during a glacial age. This glacial age, or Quarternary period on the geologic

time scale, has extended from about 2 million years ago to the present.

The current interglacial period appears to be drawing to a close. Commencing

with the retreat of the ice sheets that covered large portions of North America until

about 20,000 years ago, temperatures in the interglacial steadily rose until near the

beginning of the present or Holocene epoch around 10,000 years ago. Since then

temperatures have generally fallen, but climatic variation has persisted and

resulted in alternate warm and cool periods throughout this time (Moratto 1984,

Pielou 1991). Within the past 1,100 years for example, climates have fluctuated

between a warm period lasting about 475 years and known as the “Little Climatic

Optimum” followed by a cooler period lasting nearly 400 years and known as the

“Little Ice Age” (Moratto 1984, Woolfenden 1994). The “Little Ice Age” came to a

close only slightly more than 200 years ago at the origins of modern climates.

Modern California climates continue to demonstrate considerable variation.

For example, the periods between 1750 and 1820 and 1860 to 1880 have been

recorded as being generally very dry (U.S. Department of Agriculture 1941).

From the late 1920’s until the late 1930’s, during the “Great Dust Bowl,” and

more recently during the late 1970’s, 1980’s and early 1990’s conditions were

again dry. Presumably, intervening periods were considered “wet.” Floods

recorded in the winters of 1861-62, 1938-39, 1955-56, 1964-65, and 1986-87 in

various portions of the state mark years of extreme precipitation (State of

California 1979). Thus, over the past 240 years, roughly 110 years of extended

drought were offset by 130 years of extended moist or “wet” conditions.

Variations in climate are both long-and short-term, and generally, the transitions

between changes are not abrupt. Thus, the climate experienced today does not

necessarily reflect what has been experienced in the past, and it is unlikely

conditions will remain any more stable in the future.

Pollen and macrofossil studies combined with glacial and tree ring

chronologies have established vegetation changes in the Sierra Nevada that track

the climatic variations over the past 10,000 years (Woolfenden 1994). These

climatic changes can have important consequences for vegetation. Most of the

tree species in these forests are long-lived, and they have grown under a variety

of climatic conditions. Many of the older members of current stands originated

and grew during the latter part of the “Little Ice Age,” but they continue to

survive and grow in the current climate, which is substantially different from
8 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

that earlier period. Most individuals in existing plant communities of the upper

montane, however, have developed since the “Little Ice Age” under the influence

of modern climates. Thus, plant communities in these forests are continually

maintaining short-term homeostatic balance while also responding and adapting

to long-term climatic variation.

The present climate of California is characterized as Mediterranean with

cool, wet winters and warm, dry summers. This basic pattern is the result of a

subtropical high pressure system that lies in the mid-Pacific Ocean and deflect

slow pressure systems originating in the Gulf of Alaska northward during the

summer. In the winter this same high moves south and allows cyclonic storms to

cross the northern portions of the state. Even in winter, however, this high and

an upper level jet stream often deflect storm tracks to the north. This condition

results in a strong north-south moisture gradient in which precipitation decreases

substantially from north to south in the range (fig. 4).

The central and southern Sierra Nevada is surrounded on three sides by arid

lands. To the west is the great central valley which lies in the rain shadow of the

coast ranges. The southern portion of this area, around Bakersfield for example,

is true desert with precipitation as low as 6 inches per year and precipitation

insufficient to recharge soil water (Major 1988). South from Bishop and east of

the range lie the hot deserts of the Mojave, while the cold continental deserts of

the Great Basin are found on the east from Bishop northward.

Figure 4—Isohyetal lines of

precipitation in the central and

southern Sierra Nevada.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 9

Rising from these deserts, the Sierra Nevada exerts a strong orographic effect

upon sites located within the range as well as those located east or “downwind” of

the range. On the western slopes precipitation generally increases with elevation to

the crest where it then decreases at a rapid rate on the east side in the rain shadow

of the range. The effect of this rain shadow is extensive. It persists across the Great

Basin to the Rocky Mountains. The state of Nevada, directly in the lee of the Sierra

Nevada, is the driest state in the nation (U.S. Department of Agriculture 1941). An

arid-humid boundary has been established at about 1,230 feet near Auburn in the

northern Sierra Nevada, 2,450 feet east of Madera in the south, and 7,870 feet above

Mono Lake on the east (Major 1988). Above these elevations precipitation exceeds

potential evapo-transpiration and the climate becomes humid.

Precipitation

Precipitation falls primarily as rain at elevations below 6,000 feet. The rate of

increase is about 7.1 inches per thousand feet of elevation gain on the westside in

the north, 6.1 inches in the south, and 7.3 inches on the eastside (National Oceanic

and Atmospheric Administration 1982). Rainfall apparently peaks from 5,000 to

6,000 feet and declines at higher elevations (fig. 5). However, at these elevations

the form of precipitation begins to change to snow (State of California, Department

of Water Resources 1991), and measurements in areas where both rain and snow

occur are difficult to determine. Differences in measurement techniques probably

result in records that show a decline in precipitation at elevations above 6,000

feet. Stations established to measure rainfall amounts do not often adequately

measure precipitation in the form of snow, and snow course measurements do

not generally account for precipitation falling as rain, particularly in the summer

and fall before a snowpack is established. Few stations account for precipitation

falling in either form, and even fewer have a substantial history. In these transition

elevations, a true estimate for precipitation is probably a composite of both types

of record. At elevations of 7,000 to 9,500 feet, which might be considered typical

for the upper montane, estimates show that between 65 and 90 percent of

precipitation falls as snow (Major 1988, State of California 1979).

The snowpack builds through the winter and generally attains maximum

depth and water content around the end of March (State of California, Department

of Water Resources 1991). Values are recorded on April 1 of each year, and this

date is used as the basis for comparisons. The average April 1 snow depth for

elevations between 7,000 and 9,500 feet are quite different by subregion. Thus,

snowpack depth in the northern portion of the study area on the westside is about

84 inches on April 1, while in the south it is 25 percent less at 63 inches. Maximums

Figure 5—Annual rainfall by

elevation for three subregions in the

central and southern Sierra Nevada.

Elevation (feet)

Annual Rainfall (inches)

North

South

East

60

50

40

30

20

10

0

500 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000
10 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

for the northern and southern portion of the study area are 247 and 219 inches,

respectively. On the eastside the snowpack averages over 71 inches, but there is a

substantial difference between station records in the northeast compared to those

in the southeast. The average on the eastside in the north is about 74 inches while

it is only 28 inches in the south. The maximum snowpack depth recorded in the

central and southern portion of the Sierra Nevada for the 50-year period 1941 to

1990 at all stations was 267 inches (22.25 feet), and this occurred on the eastside.

As elevation increases above 6,000 to 7,000 feet, the April 1 water content

increases until about 8,000 feet in the north and east and 9,000 feet in the south

(fig. 6). The rate of change per thousand feet is about 6.4 inches on the westside in

the north, 3.8 inches in the south, and 5.2 inches on the eastside. Above these

elevations water content apparently declines. A large part of this reduction may

result from redistribution of newly fallen snow by wind and higher levels of

evaporation and melting since vegetation becomes sparse at higher elevations

(Major 1988).

Regional variation in the water content of the snowpack is high in the central

and southern Sierra (State of California, Department of Water Resources 1993)

(fig. 7). The outstanding feature of southern and eastside stations is the high

percentage of sites and years that receive less than 20 inches of water from the

April first snowpack. Northern stations on the westside show a more uniform

distribution of water content over time. Thus, not only do southern and eastern

sites receive less total snowpack, they experience lower water content more

often. Years with high April 1 water content in the snowpack occur less often in

the south and east than in the north.

The location of the red fir dominated upper montane forests is highly

correlated with the snowpack. Over 90 percent of all red fir dominated sample

sites were located between 7,000 and 9,500 feet. These are the zones of maximum

April 1 snow depth and water content. On the west side, Barbour has found good

correlation between elevations of the white fir-red fir ecotone and the altitude of

the freezing level during major storms at latitudes near 39° (Barbour and others

1991). This same study also showed a sharp increase in April 1 water content

within the ecotone at latitudes between 38 and 40°, and it indicated that snow

depth could be a predictor of water content. Within the ecotone, the relative

density of red fir increased with snow depth and April 1 water content. Field

observations indicate the same relationship at somewhat higher elevations on

the westside in the south and on the eastside. The average April 1 water content

in the snowpack at elevations between 7,000 and 9,600 feet is 34.3 inches in the

north In the south it is 24.7 inches, and on the eastside it is 28.1 inches.

An important constituent of summertime weather in the Sierra Nevada is

convective buildup (National Oceanic and Atmospheric Administration 1982).

Moist air rising from the central valley in the afternoons, or warm moist air

masses originating in the Gulf of California and Pacific coast of Mexico condense

at high elevations over the crest to form large cumulonimbus clouds. Often these

clouds are accompanied by lightning, intense localized rainfall, and substantial

drops in temperature. Summertime snowstorms have been recorded in these

upper montane forests. The peak season for such convective activity is June

through September although September also includes precipitation

accompanying the first storms of fall from the Gulf of Alaska and coast of

Mexico. Average monthly summer precipitation levels in inches at representative

elevations by subregion of the upper montane include:

Elevation North South East

7,000 ft. 0.66 0.48 0.56

8,300 ft. 0.75 0.56 0.66

9,500 ft. 0.84 0.63 0.75
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 11

Elevation (feet)

April 1 water content (inches)

North

South

East

0

16

18

20

22

24

26

28

30

32

34

26

38

500 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000

April 1 Water Content (inches)

Percent of Samples

North

South

East

60

50

40

30

20

10

0

0–20 20–30 30–40 40–60 60+

Averages, however, are misleading. Most of the storms originating from

convective activity are infrequent at a specific location. They are often of high

intensity but relatively short duration. Thus, a single 2-inch precipitation event

occurring over a few hours within a 10-year period averages 0.2 inches per year

for the period. Because many of these storms are of high intensity, substantial

surface runoff occurs that is not available for long-term use by plants. The overall

effect on vegetation may therefore not be substantial. Probably as important in

regulating plant activity are the periods of lowered temperatures and higher

humidities that accompany these storms. A rainfall event may or may not occur

at a particular site, but generally cloudiness and cooler temperatures occur over

a larger area when convective storms are present, and these conditions may

persist for several days.

Temperature

Temperatures decrease as elevation increases in each of the major geographic

subregions of the study area (National Oceanic and Atmospheric Administration

Figure 6—April 1 water content of

the snowpack by elevation in three

subregions of the central and

southern Sierra Nevada.

Figure 7—Regional variation in the

April 1 water content of the central

and southern Sierra Nevada

snowpack between elevations of

7,500 and 9,000 feet.
12 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

1982). A rapid drop in temperature with elevation on the eastside as compared to

the westside in both winter and summer is apparent, and the rate of change is

greater in the summer in all areas (fig. 8). Average temperatures for January, July,

and yearlong at representative elevations in the upper montane were determined

from regression values (table 1).

Table 1—Average temperatures (°F) by subregion at

representative elevations in the upper montane.

Subregion Elevation (Feet)

7,000 8,000 9,000

North

January 32.8 30.9 28.9

July 64.0 61.8 59.7

Yearlong 46.0 43.7 41.4

South

January 34.1 32.2 30.3

July 62.5 59.6 56.6

Yearlong 45.7 43.0 40.2

Eastside

January 26.4 23.4 20.3

July 59.3 54.6 49.9

Yearlong 41.5 37.5 33.5

Average lapse rates (change in temperature per 1,000 feet of elevation change)

in degrees Fahrenheit for July (summer) and January (winter) (fig. 8) include:

North South East

January 1.9 1.9 3.0

July 2.1 3.0 4.7

On a 40° day at 4,000 feet in January, ambient air temperatures at 8,000 feet might

lie near 32° on the westside. Such a day on the eastside might be expected to

result in ambient air temperatures at 8,000 feet of 28°. A 100° day during July

near sea level in the central valley would be expected to be near 83° in the north

and 76° in the south at 8,000 feet on the westside. A similar day on the eastside in

Bishop would see a temperature of 81° at 8,000 feet.

Geology

The Sierra Nevada range is a block of uplifted granitic rocks that has been tilted

to the west. In detail, however, the geologic structure of the range is more

complex than this. It results from important events that occurred throughout the

history of the range, and it defines the character of these mountains as they are

viewed today. In the foothills and at scattered locations at higher elevations as

well as along the crest are metamorphic rocks that predate the range. In the

north, volcanic mud and ash flows have covered the granitic batholith over

extensive areas. In addition, the higher elevations have been extensively glaciated

during the Wisconsonian glaciation of North America. Volcanoes, such as those

near Mammoth Mountain, have erupted in recent history, and erosion and

faulting are continual.

Origins of the range date from the Paleozoic era more than 225 million years

ago when sediments were deposited in a shallow sea that covered most of the

range. These deposits were intruded, folded, and metamorphosed as the range

took shape. Uplifting and subsequent erosion have resulted in two major areas of
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 13

Elevation (feet)

Average Termperatures (degrees F)

North

South

April

East

70

60

50

40

30

20

1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

Paleozoic and Mesozoic metamorphic rocks present in the current landscape.

One set of these rocks is found in a belt along the western foothills; the other lies

as roof pendants in a scattered band along the crest. Most of these formations lie

outside the study area; however, scattered throughout the upper montane forests

are isolated outcrops that survived erosion and date from these periods. Within

the study area, more of these rocks were encountered in the southern portions of

the range than the north.

Sedimentary deposition of the Paleozoic era was followed by downfolding

and development of a large syncline along the axis of the range during the

Mesozoic era of 225 to 80 million years ago. This syncline was intruded by the

Sierra Nevada granitic batholith and subsequently uplifted. The granite was

intruded as hundreds of discrete plutons, apparently in several pulses (Bateman

and Warhaftig 1966, Oakeshott 1971). These plutons show differences in

mineralogy and textures that can be recognized at the surface and result from

variations in the orogenic processes that formed the range. They are generally

distributed in belts with the western rocks somewhat older than those on the

crest or eastside, and they vary in size from 1 square mile to over 500 square

miles. Quartz monzonite and granodiorite are the most abundant rocks in the

batholith (Bateman and Wahrhaftig 1966).

Figure 8—Change in temperature with elevation by subregion and time of year for the central and southern Sierra Nevada.

Elevation (feet)

Average Termperatures (degrees F)

North

South

January

East

55

45

35

25

15

1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

Elevation (feet)

Average Termperatures (degrees F)

North

South

July

East

70

60

50

40

30

20

1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

Elevation (feet)

Average Termperatures (degrees F)

North

South

October

East

70

60

50

40

30

1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000
14 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Volcanic eruptions during the Tertiary period covered substantial areas north

of the Middle Fork of the Tuolumne River. The earliest deposits were rhyolitic

tuffs, and ash flows of the Valley Springs formation that date from 30 to 20 million

years ago and range up to 800 feet thick. These were followed in sequence by the

andesitic mudflows (lahars) and latites of the Relief Peak and Stanislaus formations

that were deposited between 19 to 9 million years ago and range up to 3,000 feet in

thickness. The final deposit in the sequence was the Mehrten or Disaster Peak

formation composed of andesites, rhyolites, and basalt ranging in age from 9 to 5

million years ago. This formation is about 1,000 feet thick (Slemmons 1966). The

combination of these formations cap the ridges and upland areas of the northern

portion of the study area except in areas where the granitic batholith rose above

the volcanic flows when they were formed or was exposed by erosion later.

Tilting and further uplift of the range to present heights occurred in the

Pliocene epoch of 10 to 5 million years ago. The amount of uplift appears to be

quite variable. In the north it is estimated at about 6,000 feet, while in the south it

appears to be as high as 14,000 to 19,000 feet (Bateman and Warhaftig 1966).

Faulting, which appears to have accompanied the deformation, also began along

the eastside around 10 million years ago. In response to the uplift and tilting,

rivers incised their drainages to depths of 2,000 to 4,000 feet. From this uplift and

subsequent erosion the range obtained the deep canyons of the westside and the

dramatic relief of the eastern escarpment. Most of this downcutting was

completed before the end of the Pliocene about 2 million years ago (Bateman and

Warhaftig 1966).

Pleistocene glaciation began in the Sierra Nevada about 3 million years ago

at the same time it was occurring throughout the northern portions of the

continent and other high mountain ranges of the world. At the height of glaciation

the range bore an icecap nearly 270 miles long and 20 to 30 miles wide (Warhaftig

and Birman 1965). It extended from near the Middle Fork of the Feather River to

areas between Mount Whitney and Olancha Peak. While the icecap was large in

extent, it did not cover continuous areas, and many peaks, ridges, and aretes

were left uncovered as refugia. On the eastside glaciers extended to the adjacent

lowlands, and attained depths of over 1,000 feet. On the westside the ice

descended to elevations as low as 3,000 to 4,000 feet, but it attained much greater

depths. For example, a depth of 4,000 feet has been estimated for the glaciers of

the Grand Canyon of the Tuolumne, and the Merced glacier appears to have

attained a depth of 6,000 feet (Bateman and Warhaftig 1966). This great icepack

gradually diminished during the subsequent interglacial period until it

disappeared around 20,000 years ago.

Glaciation provided a major force that shaped the current landscape of the

Sierra Nevada. Although most of the large drainages appear to have attained

their present depths before the Pleistocene epoch, glaciers carved many of these

drainages into the characteristic “U-shaped” profiles observed in canyons

throughout the range. Other drainages retained their “V-shaped” pattern but

were downcut further. Broad areas were scraped free of weathering rock and

developing soil. Deep basins, often filled with alluvium such as Yosemite Valley,

were formed in drainage bottoms. Trenches were etched and many times filled

with debris along joints that occurred in the granitic batholith. Moraines were

formed, and this material was deposited along the sides and bottoms of canyons

as the glaciers retreated. In other places glacial till not deposited from moraines

was left scattered on the landscape. Finally, as the glaciers moved they carried

deposits from higher elevations to lower or across surfaces developing from

different parent materials. As a result, morainal ridges and glacial till were often

found to be mixtures of volcanic, metamorphic, and granitic rock types. This was

particularly common in the northern part of the study area.

More recently, during the Pleistocene and Holocene epochs, volcanic activity

has occurred on the eastside and in the southern portion of the range. Much of
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 15

this within the upper montane is located near Mammoth Mountain and Mono

Lake. Basaltic andesites, quartz-latite, and rhyolitic tuff range in age from 370,000

to as recent as 6,000 years, and possible dates as recent as 500 to 850 years ago

have been obtained from the Inyo Craters (Bateman and Warhaftig 1966). In

several areas these flows are overlain with pumice erupted from a line of craters

extending south from the Mono Craters to the Red Cones. This pumice mantle

extends as far as Kaiser Pass near Huntington Lake, and it often covers soils that

were developing at the time of eruption. Further south, along the headwaters of

the South Fork of the Kern River, are several basaltic cinder cones and flows,

including the latite domes of Monache Mountain and Mount Templeton that

appear to date from mid-Pleistocene.

Soils

Soils in the upper montane are weakly developed. Erosion from steep slopes, the

relatively short period of time since Pleistocene glaciation, and a Mediterranean

climate have limited the degree of soil development. These soils are typically

medium to coarse textured, and they often do not contain a zone of clay

accumulation or B horizon.

Soil Classification

Soils are classified into orders, suborders, great groups, subgroups, families, and

series on the basis of properties that distinguish genetic processes. Differentiating

criteria at higher levels of the taxonomy, such as soil order, are broad and general

in importance; whereas those at lower levels are more specific. Taxonomically,

upper montane soils are characterized by four orders: Entisols, Inceptisols,

Alfisols, and Mollisols. Entisols are those soil groups that show no signs of

profile development while Inceptisols are those with some development. Alfisols

and Mollisols are developed soils. Alfisols contain an argillic or clay horizon

while Mollisols have a dark, thick topsoil with high levels of organic matter.

Most samples in this study were Inceptisols. Entisols were also encountered in

substantial numbers, but Alfisols and Mollisols were uncommon (fig. 9).

The results of this study showed that Entisols occurred in higher proportions

on the eastside than elsewhere in the study area. Nearly 50 percent of the eastside

samples were Entisols. Many of these came from the cindery deposits near

Mammoth Mountain and from flow rocks on the eastside, but the highest

proportion of these sites overall came from the granitic rocks of the Sierran

batholith. Entisols also occurred in high numbers in the southern portion of the

westside. This appears to coincide with the steeper topography and drier climate

of this region.

Within the four dominant orders, Umbrepts and Ochrepts were predominant

suborders in the Inceptisols (fig. 10). Umbrepts are dark, reddish brown, acidic

soils that are freely drained and organic matter-rich. They typically occur in areas

with a Mediterranean climate. Ochrepts are light brown colored soils that are

freely drained and occur in a wide moisture and temperature range. They often

occur on steep slopes. Psamments, which are sandy soils with low available water

holding capacity (AWC; see Glossary), and orthents, which occur on erosional

surfaces and generally do not have diagnostic horizons, were common in the

Entisols. Xeralfs were the major suborder on sites with Alfisols. These are reddish

soils of Mediterranean climate that experience extended periods of summer

dryness. They often have an abrupt boundary between the A and B horizon.

Xerolls occurred more often in the few Mollisols. They, too, occur in areas with a

Mediterranean climate and are dry for extended periods in the summer.

In this study the most commonly encountered features differentiating soil

families were particle size class, mineralogy, and temperature class. As much as

50 percent of the samples were classified as skeletal in particle size class
16 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

indicating the high proportion of sites with greater than 35 percent of the volume

in rock fragments. Of the remaining samples nearly 30 percent had a loamy

particle size class, and over 10 percent were sandy. Ashy, medial, cindery, and

contrasting particle size classes were also encountered. Almost all sites were in

the mixed mineralogy class. Soil temperatures were mostly in the frigid and cryic

regimes. Over 80 percent of the sites were classified as frigid implying that mean

annual soil temperatures at 20-inches depth were estimated to be below 47° F (8°

C) but with summer temperatures warmer than cryic soils. A substantial number

of sites (14 percent) were classified in the cryic regime with mean annual

temperatures between 32 and 47° F (0 to 9° C ). Less than 5 percent of the samples

were classified in the mesic temperature regime.

Soil colors were predominantly yellow-red (YR). Essentially all of the topsoils

occurred in hues of 7.5 YR, 10 YR, or 2.5 Y. Over 90 percent of the topsoils were 10

YR in hue alone. These were yellow-red to yellow soils when moist. Few

occurrences of redder soils were encountered in surface horizons. Topsoils were

also strongly mollic in value and chroma. Over 90 percent were very dark brown,

mollic colors. Subsoils showed similar patterns. Ninety-eight percent of the

subsoils were 7.5 YR, 10 YR, 2.5 Y and 5 Y in hue. These were also yellow-red to

yellow in color when moist. Subsoils varied more in value and chroma than

topsoils. They were almost evenly distributed between high value and low value

Suborder

Percent

Umbrepts Orthents Xeralfs Xerolls Orchrepts Psamments Boralfs Borolls

50

40

30

20

10

0

Soil Order

Percent

Entisols Inceptisols Alfisols Mollisols

80

70

60

50

40

30

20

10

0

Figure 9—Percent of soil samples

by soil order in the central and

southern Sierra Nevada.

Figure 10—Percent of soil samples

by soil suborder in the central and

southern Sierra Nevada.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 17

showing wide ranges in light versus dark colored soils. Chroma was also variable

and showed uniform distributions between soils that were strongly colored and

those that were not.

Parent Materials

Parent materials originated from six different rock types: granitic, volcanic flows,

lahars, tephra and ash deposits, and metamorphic sources. A small portion came

from sources in which rock types had been mixed either through glacial activity

or gravity. A very few sites were derived from sedimentary rocks. Granitic

sources far surpassed all other parent materials. The two largest soil orders,

Inceptisols and Entisols, were found mainly on these granitic rocks as might be

expected. Among the extrusive volcanic type parent materials, Inceptisols and

Alfisols were found almost exclusively on the lahars; whereas Entisols were

found more commonly on volcanic flows, tephra, and ash deposits. Soils derived

from metamorphic rocks and mixed rocks were most commonly Inceptisols.

Soil Development

As elevation increased, soil classification changed at the order level and

additional differences in soil characteristics were found. Together these features

seemed to reflect climate change with increased elevation. The relationship was

not direct because soil formation generally depends upon other factors such as

parent material, topography, vegetation, and time, and their influence was not

usually equal for a given soil. However, as elevation increased, the proportion of

Entisols increased while the proportion of Inceptisols correspondingly decreased

(fig. 11). Surface horizons also became more ochric, or pale colored, and

subsurface horizons became lighter (higher values in the Munsell color chart)

and less gray (higher chromas). AWC tended to decrease, and textures in both

the surface and subsurface horizons became sandier and more coarse textured as

elevation increased. These observations reflect results found in other

mountainous regions of the world (Birkeland 1974, Wilde 1958).

Topographic setting often plays an important role in soil formation. The

results showed that aspect was an important topographic feature of the study

area that is correlated with the occurrence of plant communities. Other studies

have indicated that aspect is a significant factor in soil development, assuming

that higher temperatures accelerate soil reactions and therefore soil formation

(Birkeland 1974). However, a strong correlation between aspect and soil

temperature was not observed in the study area. In these forests, soil

temperatures are correlated primarily with tree cover and less so with aspect or

Elevation (feet)

Percent of Samples

LT 7,500 7,500–8,000 7,000–8,500 GT 8,500

Inceptisols

Entisols

50

60

70

80

90

40

30

20

10

0

Figure 11—Percent of Inceptisols

and Entisols on granitic and volcanic

parent materials in relation to

elevation.
18 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

elevation. Many sites on south aspects in the upper montane have dense stands

of trees. In such stands soil temperatures were generally cool; whereas open

sites, regardless of aspect, were generally warmer. AWC, soil taxonomy, and

topsoil depth were also found to be uncorrelated with aspect when parent

materials were held constant.

Topographic position, such as ridge top or toeslope, was correlated with soil

development. Thus, surface horizon colors became more ochric or pale colored on

upper slopes while soil depth and AWC increased on lower slope positions. Textures

in both surface and subsurface horizons were sandier and more coarse textured on

ridges and upper slope positions and loamier on lower slopes and benches.

Taxonomically, soils were more skeletal in ridgetop and upper slope positions

indicating a higher proportion of coarse fragments encountered in the profiles.

Soils and Vegetation

The relationship of soil classification to plant association is difficult to assess

because of the dependence of each on several other factors as well as the

interaction between soils and vegetation. In most cases in this study, when plant

association was compared with soil classification at the family or series level,

correlation was low. Practically every association occurred on soils of at least

three different great groups and many more families (appendix B). However,

when vegetation at a broader level such as plant series or subseries (appendix A)

was compared with soil order or suborder, some patterns did emerge. Thus,

while all plant associations in the upper montane occurred on Inceptisols, some

plant communities at the subseries level were found more frequently on Entisols.

These were the lodgepole pine and Jeffrey pine series, and the red fir-western

white pine subseries. A second group also occurred in significantly higher

proportions on Alfisols and Mollisols. These were some of the lodgepole pine,

mountain hemlock, and quaking aspen series, and the white fir-sugar pine-red

fir and red fir/mountain mule ears subseries.

Although the relationship between soil taxonomy and vegetation

classification was often not clear, several soil properties were found to exhibit

correlations with vegetation in these communities. Most important were soil

depth, thickness of the topsoil, coarse fragment content, AWC, summertime soil

temperature at 20 inches, soil texture, and pH. Plant communities generally

occur on a continuum with a range of values for each of these soil characteristics.

Rarely do they occur on soils with a limited range of values. Broad relationships

were found, however, between vegetation composition and each of these soil

properties, and comparisons can be made between plant communities at a series

or subseries level.

Nearly two-thirds of all samples had soil depths greater than 35 inches;

however, the mountain hemlock, Jeffrey pine, and western juniper series had

high occurrences on soils of less than 35 inches. The western juniper series in

particular contained the shallowest depths overall with a significant number of

stands occurring on sites with less than 20 inches of soil. The red fir/mountain

mule ear plant association fell into two major groups: those with soil depths less

than 25 inches, and those with depths greater than 35 inches. Floristically,

however, stands in this association were similar. These differences in depth

reflected variation across the landscape and implied that factors other than soil

depth may be regulating stand composition and structure in this association. The

deepest soils were encountered in the quaking aspen series and the red fir-white

fir, red fir-lodgepole pine, and red fir subseries. The Bolander’s locoweed

association also occurred on sites with deep soils.

Topsoil depths averaged over 9 inches on all sites; however, a fairly large

number of stands had topsoils of less than 7 inches. The mountain hemlock

series, the red fir-western white pine, and a high proportion of the red fir

subseries were in this group—all forested sites occurring at higher elevations.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 19

The deepest topsoils were found in the quaking aspen and western juniper

series and the Bolander’s locoweed association. Most of these communities had

high forb and grass cover and (except for quaking aspen) low tree densities.

These results correlated with the observations on soils in forest-prairie

transitions wherein forested sites had relatively shallow surface horizons and

grass and forb dominated sites had deeper topsoils (Birkeland 1974).

Coarse fragment content in topsoils were substantially less than in subsoils

on most sites. Coarse fragments increased from about 20 to nearly 40 percent

with depth in average stands. Soils in the red fir-white fir and red fir-lodgepole

pine subseries and the quaking aspen series had large numbers of samples with

less than 35 percent coarse fragment contents throughout the profile. At the

opposite end of the spectrum, the western juniper, Jeffrey pine, and mountain

hemlock series had relatively high occurrences on sites with coarse fragments

exceeding 35 percent throughout the profile. The western juniper subseries in

particular had more than 35 percent coarse fragments in nearly one-third of the

topsoil and two-thirds of the subsoil samples.

AWC ranged up to 6.9 inches for the 40-inch profile with an average of about 3

inches. The quaking aspen series and the red fir-white fir and red fir-lodgepole pine

subseries typically were found on soils with the highest water holding capacity,

while low values were commonly encountered in the mountain hemlock, Jeffrey

Pine, and western juniper series and the red fir-western white pine subseries.

Plant associations with naturally lower stocking levels under undisturbed

conditions tended to have the warmest soils. High numbers of samples with

warm soils occurred in the Jeffrey pine and western juniper series and the

Bolander’s locoweed association. Summertime temperatures on these sites

generally exceeded 50° F. Except for the Bolander’s locoweed association, these

are also the plant communities that often occur on south facing aspects. The

coldest soils were found in the mountain hemlock series, as might be expected

from their generally dense tree cover, north aspects, and steep slopes. The red fir

and red fir-white fir subseries also contained cooler soils. Soil temperatures were

typically less than 49° F in these stands.

Soil textures were typically sandy loams and loams throughout the profiles.

In general, soils in the upper montane can be considered moderately-coarse to

moderately-fine textured. Soils in the red fir series contained high proportions of

sandy loams while significantly higher numbers of loams were encountered in

the lodgepole pine series. A substantial number of sites also occurred in coarse

textured sands. The red fir-western white pine subseries and the Jeffrey Pine

series, for example, have a significantly higher proportion of sites on these coarse

textured soils. Soils in these stands were often modified further with high gravel

content throughout the profile. The quaking aspen series, on the other hand, had

higher levels of sandy clay loams and clay loams in the profiles, which were

considered moderately fine textured soils. Few sites with clay textures were

encountered in these forests.

Soil pH was basically acid in both topsoil and subsoil. Averages overall were

about 5.8. The quaking aspen and western juniper series, and the white fir-sugar

pine subseries had the highest average pH in surface horizons at 6.0 to 6.2, with

ranges up to 7.1. Conversely, the lowest pH was encountered in the mountain

hemlock series with an average of 5.3, and individual sites in this association

were recorded as low as 4.3. The Bolander’s locoweed plant association also had

consistently low pH values. The higher pH under quaking aspen was probably

because many hardwood stands have more basic soil reactions (Birkeland 1974,

Wilde 1958), but the results did not explain the higher pH levels under stands in

the western juniper and white fir-sugar pine subseries, although the shrub

component on these sites could be a contributing factor. The western juniper

subseries usually has a consistently high shrub component, and many stands in

the white fir-sugar pine subseries also have substantial shrub understories;

however, other stands with high shrub levels do not show a similar response.
20 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Vegetation

Overview

From elevations below 1,000 feet to those above 14,000 feet, the Sierra Nevada is

broadly zoned into vegetation bands within which characteristic plant

communities occur. At the lowest elevations on the westside are annual grassland

steppes mixed with blue oak (Quercus douglasii) occurring in savannah-like

woodlands. At slightly higher elevations a sclerophyllous evergreen shrub and

tree component commonly referred to as chaparral emerges, while at still higher

elevations the beginnings of a coniferous forest dominated by ponderosa pine

(Pinus ponderosa) is found. These communities are followed by forests of mixed

coniferous species known as the Sierra Nevada mixed conifer type (Eyre 1980)

and dominated by mixes of ponderosa pine, sugar pine (Pinus lambertiana), white

fir (Abies concolor), and incense cedar (Calocedrus decurrens). Above, the upper

montane forests are found. They are generally characterized by the presence of

red fir and lodgepole pine (Pinus contorta). They are followed at still higher

elevations by the coniferous forests and woodlands of the subalpine zone typified

in most cases by pure stands of lodgepole pine and whitebark pine (Pinus

albicaulis) in the north or lodgepole pine and foxtail pine (Pinus balfouriana) in the

south. At the highest elevations of the range an alpine zone of low forb and grass

communities predominates. As the summits are crested and the descent down

the steep eastern side of the range proceeds, the patterns of the westside repeat

except at elevations below the upper montane: a Jeffrey pine (Pinus Jeffreyii)

dominated forest emerges, followed at still lower elevations by pinyon pine

(Pinus monophylla) woodlands mixed with sagebrush (Artemesia tridentata)

shrublands at the edge of the Great Basin.

One species provides a common thread throughout the upper montane

forest of the Sierra Nevada: red fir. This species, more than any other,

distinguishes the upper montane from the mixed conifer forests at lower

elevations and the subalpine forests above (Barbour and Major 1988, Rundle and

others 1977). However, not all forested or woodland stands in the upper montane

are dominated by red fir, and many do not even contain red fir. Eyre (1980) for

example, documents at least 10 vegetation types that contain red fir as an

associated species. Nevertheless, in most stands red fir is present, or it lies within

adjacent stands at similar elevations.

Red fir is present in the central and southern Sierra Nevada as two varieties:

California red fir (Abies magnifica var. magnifica) and Shasta red fir (Abies magnifica

var. shastensis). During the study a line of demarcation could not be precisely

determined between the two; however, a latitudinal division occurs near the

Middle Fork of the Kings River at latitude 36°50'. South of the Middle Fork,

stands contain Shasta red fir. Just to the north, near Wishon Reservoir, scattered

individual Shasta red fir have been found, but further north, as far as the limits of

the study area along the Middle Fork of the American and Rubicon Rivers,

stands appear to contain only California red fir. Whether stands on the Monarch

Divide between the Middle and South Fork of the Kings River contain Shasta red

fir is unknown at this time.

Red fir is seldom encountered south of Mammoth Mountain on the eastern

escarpment until the Kern Plateau is reached. Canyons south of Mammoth

Mountain such as Convict Creek and Hilton Creek contain extremely small stands,

and one small stand growing in association with foxtail pine occurs near Onion

Valley west of Independence, but no others were found in this portion of the range.

A smaller break in the northern distribution on the eastside apparently lies between

Reversed Peak near June Lakes and Green Creek southwest of Bridgeport.

Other species also demonstrate strong latitudinal or longitudinal gradients or

occupy unique settings within the study area. Mountain hemlock (Tsuga

mertensiana), for example, lies predominantly north of the South Fork of the Kings
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 21

River. Stands lie as far south as Mount Silliman at latitude 36°3' (Parsons 1972).

However, north of Yosemite near latitude 38°, stands begin to become a common

feature in the upper montane forests. Sugar pine and incense cedar are two species

that essentially do not occur in eastside stands. Huckleberry oak (Quercus

vaccinifolia) is found primarily north of the Kaiser Pass area on the San Joaquin

River on the westside, and north of Sonora Pass on the eastside. This species

occurs primarily on granitic parent materials as does Sierra chinquapin (Castanopsis

sempervirens). Snowbrush (Ceanothus velutinus) and sticky-leaved rabbit brush

(Chrysothamnus viscidiflorus) are located only on the eastside. Mountain mule ears

(Wyethia mollis) is an herb that forms distinctive communities on the volcanic soils

of the Merhten formation from north of Yosemite National Park through the

northern limits of the study area. Gray’s lovage (Ligusticum Grayii), a common forb

in some lodgepole pine communities, is rare in the southern portion of the

westside, and it is essentially absent on the eastside south of Ebbetts Pass.

Quaking aspen (Populus tremuloides) is one of the most widely distributed

species in North America (Jones 1985, U.S. Department of Agriculture 1965). It

occurs on moist habitats throughout the upper montane, but stands are often

widely scattered on the westside, particularly in the south. Westside stands are

typically quite small. Many are less than one acre and most are less than 5 acres.

Often small aspen patches finger through larger communities to form a mosaic

across a hillside. Barry (1971) has found sharp ecotones between communities in

this arrangement. Eastside locations south of Mammoth Mountain Lake are also

widely separated, but north of Mono Lake, and particularly north of Conway

Summit on Highway 395, stands become more common and larger than those on

the westside. Fairly large stands reminiscent of those in the Rocky Mountains are

present in the northeastern part of the study area around Hope Valley near

Carson Pass. Many aspen stands in the Sierra are being invaded by conifers. In

some cases, these invasions appear to be the result of the combined effects of

long-term fire suppression and grazing. In other cases, causes do not appear to

be so directly related.

Quaking aspen stands may also contain some of the oldest organisms in the

Sierra Nevada. Sexual reproduction is rare in the west, and most stands reproduce

vegetatively by suckering. Individual clones resulting from this process can persist

for thousands of years, and it has been suggested that most current clones in the

Great Basin are at least 8,000 years old (Jones and DeByle 1985).

At lower elevations on the westside, white fir, sugar pine, and incense cedar

generally grow in association with red fir, and in scattered instances, such as at

the Freeman Creek and Tuolumne Groves, Giant Sequoia grows in association

with red fir. Western white pine (Pinus monticola), mountain hemlock, and

lodgepole pine are common associates at higher elevations. At the upper

boundary with the subalpine zone, whitebark pine and, in the south, limber pine

(Pinus flexilis) and foxtail pine begin to appear in stands. They can be used as

indicators of the transition to subalpine. Jeffrey pine and western juniper

(Juniperus occidentalis) form communities with red fir on shallow sandy soilsover

a wide range in elevation. Lodgepole pine and quaking aspen occupy moist sites

on lower slope positions and benches.

For all samples in the study area elevation ranges include:

Elevation (ft)

Latitude (degrees) Westside Eastside

38+ 5,780-9,160 5,860-9,100

37-38 6,160-9,200 7,800-9,520

37- 6,680-9,460 8,120-9,640

Dense, essentially pure red fir stands (stands with tree cover exceeding 50

percent) occupy an elevational band of about 2,000 feet throughout the range
22 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

although actual elevations vary by subregion. Elevations encountered by these

stands in the north, for example, were between 6,660 and 9,120 feet while in the

south, they occurred between 7,240 and 9,240 feet. Eastside stands lie between

7,180 and 9,200 feet.

Community Structure

Individual stand physiognomy is variable in the upper montane because of

substantial variation in height, diameter, and density of species dominating or

characteristic of each association. Tree height falls naturally into three categories.

Species such as red fir, white fir, sugar pine and Jeffrey pine can be quite tall.

These species commonly averaged taller than 130 feet, and the tallest individuals

exceeded 200 feet. Lodgepole pine, western white pine, and mountain hemlock by

comparison, are mid-height trees that usually average around 90 feet with the

tallest individuals exceeding 125 feet. Western juniper and quaking aspen are the

shortest species with heights averaging between 50 and 70 feet. The tallest western

juniper was measured at 72 feet, and the tallest quaking aspen measured 121 feet.

Diameters generally follow these same patterns. Larger red fir, white fir,

sugar pine, and Jeffrey pine will usually have diameters at breast height that

exceed 40 inches. The largest red fir was measured at 74 inches diameter. Larger

individuals of western white pine and mountain hemlock can be as large as 45 to

50 inches with averages around 32 inches. Lodgepole pine is generally taller than

western white pine and mountain hemlock, but diameters are generally smaller.

Lodgepole averages 27 inches in larger individuals, although the largest diameter

measured was 44 inches. Western juniper is a short tree with quite large

diameters. Averages for large individuals are around 48 inches, but the largest

tree measured was substantially larger at 92 inches. Quaking aspen, on the other

hand, is much smaller with the larger members of a stand averaging near 16

inches. The largest individual was measured at 27 inches.

Stand densities are quite variable depending on plant community. The red

fir plant association is dominated by red fir. It has one of the highest average

stand density indexes at 517 (Reinecke 1933), and several stands exceeded 1,000

in this study. Tree cover averaged 77 percent. The red fir/pinemat manzanita

plant association, on the other hand, is also dominated by red fir, but has an

average stand density index of only 290 and tree cover averages 50 percent. A

further example of a plant association dominated by another species is western

juniper with a stand density index of 225 and tree cover that averages 33 percent.

Essentially this community is an open woodland, whereas red fir communities

are closed canopy forests.

Individual trees of each species can be quite old. Western juniper, western

white pine, and Jeffrey pine appear to be among the oldest of the upper montane

species. In fact, one individual western juniper was measured at older than 1,500

years with an estimated age of more than 2,200 years. The oldest western white

pine was over 720 years, and the oldest Jeffrey pine measured was in excess of

650 years. Red fir, white fir, mountain hemlock, and lodgepole pine are also longlived species with ages exceeding 400 years. The oldest of this group was a red fir

measured at 586 years. Lodgepole pine is commonly seen as a relatively shortlived species; however, the average age of trees measured was about 220 years,

and the oldest was measured at 443 years. The shortest lived of the upper

montane species appear to be sugar pine and quaking aspen. The oldest sugar

pine was only 248 years. Although quaking aspen clones may be quite old,

individual trees commonly do not exceed 130 years (Jones and Schier 1985). The

oldest quaking aspen measured in this study was 135 years.

Understory cover values are often a reflection of environmental conditions

within an association more than tree cover. Generally, shrub cover decreases as

tree cover increases in late seral stands, but this is not always the case, and shrub
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 23

cover within an association often does not correlate well with tree density in these

forests. For example, the Jeffrey pine/huckleberry oak plant association has an

average shrub cover of 55 percent, and stands typically have low tree density.

Conversely, the red fir association averages 2 percent shrub cover, and stands are

typically quite dense. These two associations lie at opposite ends of the spectrum.

When compared, there is a strong correlation with cover and density between

these two associations; however, within each, shrub cover is poorly correlated

with tree density. This results from environments within each that are unique.

With forbs and grasses this relationship is also tenuous. Many densely forested

communities in the upper montane have high forb and grass components.

Quaking aspen and some lodgepole pine stands are examples of such

communities with high tree cover and well developed forb and grass understories.

Species diversity is relatively uniform among all regions of the study area

although the northern portions had higher values for the Hill diversity indices

than the southern (Ludwig and Reynolds 1985). This could be expected with the

north-south, east-west distributions of many of the species. Thus, distributions

of species such as mountain hemlock, huckleberry oak, or Gray’s lovage in the

north, and the strong correlations between mountain mule ears and the volcanic

soils of the north or the occurrence of snowbrush in the northeast, provide

additional species in many northern stands that result in higher levels of diversity

as compared to the south. This seems to agree with what can be seen on the

ground, as stands in the northwestern and northeastern portions of the study

area appear more diverse in all layers.

An average of 11 species were encountered in these stands, but typically, a

few species comprised most of the cover. Thus, the average number of abundant

species on most sites was only three. This is not surprising in these high elevation

forests, for often the species with highest cover are represented by just a few tree

species. Many understories are open with few additional species, and these have

low cover values.

In addition to variation in individual stand physiognomy, the plant

associations are arranged across the landscape in patchy, spatially complex

patterns. This results primarily from variation in geology, aspect, soil

development, topography, drainage patterns, and relief among others, but it

leads to stands that are relatively small. A high proportion are less than 25 acres

in size, and few are larger than 100 acres (Potter and others 1992a). Rundle and

others (1977) describe stands ranging in size from a fraction of an acre to several

acres, and Richards (1959) has found more than 50 percent of the Sierra Nevada

montane forests to be covered with rock outcrops, meadows, shrub patches, and

lakes. Thus, the upper montane forests of the Sierra Nevada are a mosaic of

relatively small stands composed of discrete plant associations intermingled

with non-forested areas.

Disturbance Elements

Disturbances such as avalanche, wind, lightning, insects, pathogens, and fire

have long been significant features of upper montane forests. More recently,

humans as well have made substantial impacts on the processes and functions of

these same plant communities. Disturbances operate on scales of a single

organism to entire ecosystems over time frames that vary from a matter of

minutes to decades. An avalanche may occur at a given location annually, or it

may occur once during a period of a century or longer. The entire event may last

less than a minute. At each occurrence, however, several plant communities can

be affected. Few of these disturbances have been quantified, and their effect on

plant community composition and structure during long time periods is largely

speculative. This study did not examine these factors in detail; however,

descriptions of the more important disturbance elements of the upper montane
24 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

are presented, as well as documentation of the current knowledge regarding

each of these, and logical inferences of the effects on vegetation patterns.

With few exceptions, these disturbances have occurred for millennia, and

plant species and communities have evolved and adapted to them over time.

Disturbance performs important functions within the Sierran ecosystem. An

avalanche chute that effectively eliminates a stand of conifers can become a

refuge for shrubs, herbs, and grasses that otherwise would not be able to compete

in dense forests, and this can add to the overall species and structural diversity of

the area. An insect outbreak within a stand not only regulates species composition

and structure by thinning individuals and creating openings, it creates spatial

diversity across the landscape, and it can provide opportunities for shrubs, forbs,

and other low vegetation to maintain species diversity through time. Mortality

and damage from insects provides habitat for wildlife and secondary consumers,

and it can provide a critical link in the recycling of nutrients. Because of these

types of interactions, disturbances cannot be viewed as necessarily destructive or

damaging. They are major processes that develop resources for use by other

components of the ecosystem and establish system structure.

Avalanche, Wind, and Lightning

Avalanche, wind, and lightning are important disturbance elements; however,

they are often quite localized in effect. These forests are the major zone of snowfall

and snow accumulation in the state, and avalanches are not an uncommon event.

Muir (1894) noted that “avalanche chutes are of common occurrence in all the

upper forests.” Field observation indicates this is the case. Avalanches can trigger

on any slope over 30 percent in the zone of snow accumulation, but they seem to

occur more often on slopes exceeding 40 percent. Most avalanches occur in

“chutes” or gullies that have been in place for a long time. They are quite obvious

on the landscape, and they are maintained by frequent avalanche activity.

Avalanche can also occur on slopes that show no evidence of past activity.

Often in such situations older forests are damaged. Muir (1894), for example, notes

the complete removal of an older lodgepole pine stand by avalanche, and stands

containing many large older trees that have been destroyed by avalanche are not

uncommon throughout the central and southern Sierra Nevada. Commonly, these

stands lie on lower slope positions below uniform, open slopes that reach into a

zone of snow accumulation above and have few anchoring structures such as

rocks, ledges, or trees. Sometimes these slopes are surprisingly short in length.

Evidence of past avalanches can be seen in steep canyons at higher elevations

throughout the study area. They commonly affect stands across an entire drainage

floor depending on their strength. Tree regeneration layers usually remain intact,

and shrub, herb, and grass layers are undisturbed. These avalanches seem to occur

over large areas in particularly heavy snow years, such as 1986, and they are

probably linked to weather patterns preceding and during the specific event.

Wind damage is highly variable in the upper montane. Long time periods

pass with little damage, then a major event will occur, and extensive damage

results. John Muir records such an event in December of 1874 (Muir 1894). He

notes trees breaking off every few minutes throughout one entire night. In the

northern Sierra Nevada wind speeds of 70 to 78 miles per hour were recorded for

the Columbus Day storm of October 12, 1962 that also caused major damage in

red fir and white fir stands. Intervening years showed little damage from wind

(Gordon 1973a). This storm was felt the entire length of the Sierra Nevada. For

example, a localized patch of windthrow in a red fir stand on the Sequoia

National Forest was dated to that storm during field investigations for this

study. Taylor and Halpern (1991) examined radial growth patterns within two

red and white fir stands in the southern Cascades, and they found releases in the

early 1970’s and 1980’s that were attributed to windstorms.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 25

In general, however, damage from wind is light. The only study of the effect

of wind damage on upper montane forests in the Sierra Nevada illustrates

several points (Gordon 1973a). Over a 6-year period damage affected only 9

percent of the stand volume, and most of this occurred in two wind storms. The

study also found most of the damage resulted from uprooting and breaking of

individual trees rather than groups, and intermediate crown class trees were

more affected than any other tree class. As might be expected, the amount of rot

and wind damage were strongly correlated. On the other hand, tall dominants

that have been exposed to winds for long time periods, withstood high winds

very well. Finally, effects were often very localized and not related to the direction

of prevailing winds. These results seem to correlate with observations throughout

the Sierra Nevada and indicate that in the upper montane, disturbance from

wind is correlated with small gap formation within most stands.

Lightning kills or damages single trees. It assumes importance in the upper

montane because of the high frequency of lightning strikes. Aside from its role in

fire occurrence, lightning also develops gaps within tree canopies. Often trees

seem to explode and split into pieces that are scattered over wide areas. Muir

(1894) noted trees 200 feet high and 50 to 60 inches in diameter that “were split

into long rails and slivers from top to bottom and scattered to all points of the

compass.” These individuals are often simply killed. White fir and red fir appear

to be particularly suseptible to shattering. In other cases a large groove is created

down the length of the tree, and the tree survives although it is disposed to attack

by insects and pathogens. Finally, lightning often kills the tops of trees. This

predisposes the tree to attack by insects or pathogens, but just as importantly in

the case of true fir, such damage often limits future cone production.

Insects and Pathogens

Insect and pathogen populations are generally active throughout the growing

season across all portions of the forest. Populations increase or decrease

depending on a variety of factors, but commonly they respond to short-term

environmental conditions such as droughts, changes in vegetation, or interactions

between themselves. The effects on a particular plant community are also variable

depending on the plant species, stand structure, stocking levels, and stage of

growth. Many of the insect and pathogens of the upper montane are relatively

species specific. Under low level or background conditions individual trees and

small groups are generally affected, and the effects appear fairly inconspicuous;

however, little is known about the ecological impacts of insect activity during

non-outbreak periods (Mattson and Addy 1975, Moeck and others 1981, Williams

and others 1992). During a population build up and development of “epidemic”

conditions the same effects may be observed but simply on a larger, more

obvious scale. In both cases removal of individuals and groups affects species

composition and stand structure of the remaining stand that can affect future

species composition and structure.

Bark beetles in the order Coleoptera are major contributors to mortality

within the tree component. Several of these affect pine species common in these

forests. The Jeffrey pine beetle (Dendroctonus jeffreyii) affects only Jeffrey pine.

The mountain pine beetle (Dendroctonus ponderosae) affects lodgepole pine, sugar

pine, and western white pine. These two species have the potential to kill large

numbers of trees when conditions allow populations to build. Engraver beetles

in the genus Ips are often associated with bark beetle attack, but occasionally can

kill small-diameter trees and top-kill larger pine as well. The emarginate ips (Ips

emarginatus), and the pine engraver (Ips pini) can attack and kill all of the pine

species found in the upper montane. Red fir and white fir can be killed on a fairly

large scale by the fir engraver (Scolytus ventralis) (Furniss and Carolin 1977).
26 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Several moths of the order Lepidoptera are defoliators that contribute to

mortality and growth loss. The Douglas fir tussock moth (Orgyia pseudotsugata)

attacks white fir in California, and of the defoliating insects in the upper montane,

it has probably the highest potential to cause top-kill, mortality, and short-term

growth loss in stands containing white fir. The western spruce budworm

(Choristoneura occidentalis) is one of the most extensive defoliators in Western North

America, and it occurs principally on white fir. Currently, it has not been reported

from the central and southern Sierra Nevada. The Pandora moth (Coloradia pandora)

affects all of the pine species in the upper montane, but the most recent outbreaks

have involved Jeffrey pine. This species favors habitats with loose upper layers of

duff and soil such as the pumice soils near Mammoth Mountain where recent

outbreaks have occurred. The lodgepole pine needle miner (Coleotechnites milleri)

primarily affects lodgepole pine, but it can also attack western white pine and

mountain hemlock. To date, this species has been observed primarily within a

localized area around Tuolumne Meadows in Yosemite National Park. Mortality

can occur as a result of repeated defoliations by the needle miner, but most often

defoliated trees are attacked and killed by mountain pine beetle.

Pathogens causing substantial damage to trees in these forests include three

main categories: mistletoes, root diseases, and rusts. True mistletoe (Phoradendron

spp.) occurs on several conifer species in the upper montane such as white fir,

western juniper, and incense cedar, but in most cases the effects are not substantial.

By far the most damaging losses are from dwarf mistletoes (Arceuthobium spp.).

Most dwarf mistletoe is host specific and occurs on one or at most a few species. For

example, Arceuthobium abietinum(f.sp. concoloris) occurs only on white fir while

Arceuthobium abietinum(f.sp. magnificae) occurs only on red fir. Together, these two

species are widely distributed, and they constitute one of the most serious forest

disease problems in the management of true fir (Scharpf 1993). The species of dwarf

mistletoe that cause major damage on tree species in the upper montane include:

Dwarf Mistletoe Species Host Tree Species

Arceuthobium abietinum(f.sp. concoloris) White fir

Arceuthobium abietinum(f.sp. magnificae) Red fir

Arceuthobium americanum Lodgepole pine

Arceuthobium californicum Sugar pine

Arceuthobium campylopodum Jeffrey pine

Arceuthobium tsugense subsp. mertensianae Mountain hemlock,

western white pine

In true fir stands, the cytospora canker (Cytospora abietis) is commonly associated

with dwarf mistletoe infections. Branches infected with dwarf mistletoe are

commonly attacked and killed by this cytospera.

Root disease is becoming more important in western forests. This is largely

because of past practices that have increased the incidence and severity of these

pathogens. Of the indigenous species infecting trees in the upper montane,

annosus root disease (Heterobasidion annosum) is clearly the major contributor to

mortality. Worldwide, this has become one of the major disease problems in

managed stands, and it is abundant in the true fir forests in California. The

fungus spreads through root contact or spore dispersal to cut or damaged stems

of adjacent trees. Although many centers die out quickly, the disease has been

recorded as surviving as long as 50 years in a single stump; so that future

generations of trees can be infected. There are two host specific forms: one that

infects mostly pines and incense cedar, and one that infects true fir, hemlock, and

giant sequoia. In pine stands the disease can kill host trees rapidly. In fir stands it

causes a butt rot, but it generally does not kill the host directly. On the eastside it

apparently can cause outright mortality on fir (Scharpf 1993), and it does increase

the susceptibility of host trees to insect attack and windthrow.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 27

White pine blister rust (Cronartium ribicola) is an introduced fungus that has

become the major contributor to tree mortality among the five-needled pines. It

is host specific to this group of pine, and it is known to attack all of the white pine

and all species in the genus ribes, which is its alternate host, in the upper

montane. Although it has caused substantial damage to younger sugar pine trees

at lower elevations of the study area, the disease has not been observed to cause

significant damage to larger sugar pine trees or to higher elevation species such

as western white pine and whitebark pine. Because this species has been

introduced to the central and southern Sierra Nevada probably within the past

30 years, the long-term outcome of its presence in these forests is unknown.

Obviously, there has been little time for host and disease to coevolve in similar

environmental settings and for a more or less stable condition to develop. In the

short run, it now appears as if a substantial change in species composition could

be taking place at least in younger age classes at lower elevations. The ecological

importance of these changes has not been studied extensively.

Fire

The species composition and structure of the upper montane reflects the

ecological adaptation of both species and communities to the fire regime of these

forests. Thus, the fire regime of this particular region contains an underlying

evolutionary significance (Mutch 1970). The fire regime in any area can be

described in terms of the frequency of fires, their size, and their severity (type

and intensity). The red fir and lodgepole pine forests of the southern Cascades

and Sierra Nevada have been characterized as lying in a moderate severity fire

regime (Agee 1990). Forests in this regime tend to have longer (25 to 100 year) fire

return intervals, and fires have a wide range of effects. Evidence for fires is

abundant in the upper montane. About 40 percent of all samples sites in this

study showed signs of the presence of fire through fire scars, burned stumps, or

charcoal on the surface or in soil profiles. Yet, relatively little is known about fire

regimes in this portion of the Sierra Nevada. Gradually, evidence is being

obtained, so that current knowledge of lightning patterns, fire frequency, fire

size, and fire severity can be summarized.

Lightning Patterns—Lightning is a common feature in summer afternoons

during most years, and fire ignitions from this source are higher in the upper

montane than at lower elevations. Van Wagtendonk (1993a) documents a higher

proportion of lightning strikes in relation to area of upper montane in Yosemite

National Park over a 5 year period. The maximum number of strikes were

observed between 9,000 and 10,000 feet in lodgepole pine and subalpine forests.

Fire starts from lightning are also higher in the upper montane than at lower

elevations. For example, in Sequoia National Park red fir forests cover 13 percent

of the park lands, but 21 percent of all lightning fires occurred in this vegetation

type (Taylor, pers. comm.). Similarly, in Yosemite National Park approximately 70

percent of all lightning fires occurred between 6,000 and 9,000 feet elevation, and

the maximum number of fires occurred in the red fir type (van Wagtendonk

1993a). Vankat (1985) noted that fires in the upper montane have been most

common in elevations between 6,600 and 9,800 feet. On the six National Forests

within the study area about 60 percent of all lightning fires occurred above 6,500

feet on the westside and 7,500 feet on the eastside. Significant differences have

been found in the distribution of these upper elevation fires by subregion. Fires

occur at upper elevations on the eastside and southern portion of the study area

more commonly than in the north. In the north, for example, only 46 percent of the

fires occurred at elevations above 6,500 feet; whereas, in southern forests on the

westside, 64 percent occurred at higher elevations, and on the eastside 60 percent

started at elevations higher than 7,500 feet (Bailey, pers. comm.).
28 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Fire Frequency—The actual number of fires starting per million acres per year is

quite variable. One study in the Emigrant Basin Wilderness Area, which covers

about 112,000 acres, averaged nearly three fires per year between 1951 and 1973

(Greenlee 1973). Another study in the Natural Fire Management Zone of SequoiaKings Canyon National Park averaged six fires per year between 1950 and 1973 (no

acreage reported), and a 14,700 acre drainage in the same area averaged three per

year (U.S. Department of Interior 1975). Kilgore (1971) reported 13 fires less than

one-fourth acre in size over 20 years within a 5,000 acre area of Sequoia-Kings

Canyon National Park. Van Wagtendonk (1986) recorded 17 fires per year on

355,540 acres over a 53-year period. National Forest records indicated 6,865 fires

in upper montane elevations over a 22-year period on an estimated 2 million acres

of the study area (Bailey, pers. comm.). Most of these fires were small and many

occurred that were not reported (Greenlee 1973, Vankat 1985). Comparatively, the

results of these reports can be summarized as:

Study No. Fires/Million Acres/Year

Kilgore (1971) 130.0

Greenlee (1973) 26.8

U.S. Dept. of Interior (1975) 204.1

van Wagtendonk (1986) 44.0

Bailey (pers. comm.) 156.0

Fire return intervals have been approximated from five studies. These estimates

are based on fire frequency or the interval between fires at a single point or small

piece of ground. In the southern cascades a fire return has been estimated at 40

years in low elevation red fir (Agee 1990). Taylor and Halpern (1991) also estimated

a 41-year average with a range of 5 to 65 years based on 17 trees in 2 stands in the

southern cascades. Further study in the same area by Taylor (1993), however,

indicated average fire return intervals of about 13 years for small fires with a range

of from 1 to 57 years and 26 years with a range of from 5 to 47 years for larger fires.

Intervals appear to lengthen in the central and southern Sierra Nevada. On the

basis of a sample of 16 trees adjacent to three stands in the southern Sierra Nevada,

Pitcher (1987) estimated an average return interval of 65 years with a range of 5 to

126 years. On the basis of 117 trees within 68 stands in the central and southern

Sierra, an interval of 53 years with a minimum of 7 years and a maximum of 141

years was estimated.1

 These differences seem consistent with fuel patterns in the

two areas. In the north, topography is more gentle and vegetation is more

continuous; whereas, in the south, the landscape is more fragmented, natural

fuelbreaks are more common, and the vegetation less continuous.

These estimates contain inherent difficulties. First, not all trees are scarred in

a fire. This is particularly true in the upper montane; for example, Kilgore and

Taylor (1979) estimated only 20 percent of the trees were scarred in lower

elevation red fir types, and only 15 percent of the trees in any one stand that were

scarred.1 Second, scarring may not record all fires in a stand. Low intensity fires

may cause little to no scarring while intense fires may kill all the trees in an area

and leave no scars. This is particularly true on very young trees or on older trees

that carry long records. Because of thick bark, other trees may not scar for several

fires until the cambium is killed and the bark peels away. Then several fires may

be recorded, but after the bark regrows and insulates the cambium from further

damage or the tree dies, records become lost once again. Thus, individual trees

are often not accurate gauges of fire frequency, and estimates based on them

must be considered “first approximations” at this point. Nevertheless, the pattern

does seem to contrast with those at lower elevations where intervals average

between 8 to 10 years and range between 2 to 25 years (Kilgore and Taylor 1979,

van Wagtendonk 1985).

1 Unpublished data on file at

Supervisor’s Office, Stanislaus

National Forest, Calif.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 29

Fire Size—Fire size in the upper montane ranges widely; however, the

overwhelming majority of fires appear to be small. Thus, of 39 lightning-caused

fires reported in the Emigrant Basin Wilderness Area between 1951 and 1973,

nearly 80 percent were less than 

1⁄4 acre, and none were larger than 10 acres

(Greenlee 1973). Of the 6,865 fires on the 6 National Forests in the study area

between 1970 and 1992, 85 percent were smaller than 0.25 acre and 99 percent were

smaller than 10 acres (Bailey, pers. comm.) In Sequoia-Kings Canyon National

Park between 1968 and 1973, 80 percent of the fires were smaller than 

1⁄4 acre, 87

percent were smaller than 10 acres, and only 13 percent were larger than 10 acres

(U.S. Department of Interior 1975). Similar results were noted by van Wagtendonk

(1993a) in Yosemite National Park where 56 percent of the fires occurring at higher

elevations between 1972 and 1993 were less than 0.25 acre, and 82 percent were

smaller than 10 acres (fig. 12). Kilgore (1971) reports a fire in the upper montane

that was suppressed at 

1⁄4 acre in 1968, but he indicates the fire would have had

little impact and probably would have gone out at a small acreage even if it had

not been suppressed. He reports another that burned 2 months and covered less

than 2 acres. Reporting on prescribed natural fire areas in Sequoia-Kings Canyon

National Park, Kilgore and Briggs (1972) note that out of 53 fires in a 4-year period

all but 4 burned less than 10 acres. Most of these fires were less than 1 acre and went

out in a few days.

Fires reported on National Forest lands occurred under fire suppression

policies. Whether they were actually suppressed at reported acreages or

suppressed at all is unknown; access is difficult in much of the upper montane,

and many of these fires had grown to near their maximum size by the time

suppression efforts were initiated. Those reported for Sequoia-Kings Canyon

and Yosemite National Parks occurred in prescribed natural fire areas where

generally no suppression effort is initiated, and they appear to substantiate this

view of fire size at higher elevations.

Moderate size fires are also an important feature of the upper montane. In

fact, the largest amount of acreage burned at higher elevations in Yosemite

National Park between 1972 and 1993 was from fires that were between 10 and

1,000 acres in size (van Wagtendonk 1993b) (fig. 13). For example, in the red fir

type, 7,774 acres were burned in fires larger than 1,000 acres; whereas fires

between 10 and 1,000 acres burned 13,136 acres, and only 307 acres were burned

in fires that were less than 10 acres. The average size fire larger than 10 acres was

estimated at 258 acres in the red fir type and about 168 acres in the lodgepole

pine type (van Wagtendonk 1993a). Of two fires in red fir forests within SequoiaKings Canyon National Park, one grew to 452 acres over the course of a month

before going out. Another burned for 3 months and eventually reached 115 acres

before going out against natural barriers (Kilgore and Briggs 1972).

Fires larger than 1,000 acres are not rare. In a single drainage of SequoiaKings Canyon National Park 3 fires in lower elevation upper montane stands

burned about 7,300 acres in consecutive years (U.S. Department of Interior 1975).

In 1977 another series of lightning fires in the same general area consumed more

than 10,000 acres. These fires started in July and burned into September

(DeBenedetti and Parsons 1979). Three recent fires in Yosemite burned areas in

the upper montane that ranged in size from 1,126 to 1,357 acres. They were part

of larger fires that burned in lower elevation forests as well (van Wagtendonk,

pers. comm.).

Often moderate and large fires appear to occur at the interface with the lower

montane (mixed conifer) forests where fires may start at lower elevations, move

into the upper montane, and cover substantial acreages before eventually dying

out. A dramatic example of this occurs on south facing aspects in practically all of

the major river canyons that dissect the Sierra. The steep sidewalls of these

canyons are shrub dominated, but typically above a major break in slope they

become dominated by conifers. If elevations are high enough, the species
30 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

composition is dominated by upper montane taxa. Because the shrub fields

gradually succeed to conifers, it is surmised that fire plays a major role in

maintaining them as shrub dominated communities. At the break in slope and

above, fire climate changes and fire intensity and severity is reduced.

Depending on fire weather and fuel conditions, fires moving from lower

slopes may burn for extended periods and can cover large acreages at higher

elevations. Recent National Forest fire history supports this view. Thus, the

Stormy and Clover fires on the Sequoia National Forest, the Rock Creek fire on

the Sierra National Forest, the Dardanelle fire on the Stanislaus National Forest,

the Wright’s fire on the Eldorado National Forest, the Rainbow fire on the Inyo

National Forest, and the Acorn fire on the Toiyabe National Forest were all large

fires that originated at lower elevations under extreme fire weather, and they

were suppressed as they reached the upper montane forests.

Fire Effects—Large stand-replacing fires are not common, but fires often burn

with varying intensities and severity within stands and between stands in the

upper montane. Thus, within a single stand areas with little damage to vegetation

may be interspersed with areas in which all vegetation is killed, or one stand may

be severely burned while another is burned lightly. The effects vary depending on

combinations of several different environmental factors such as temperature,

Fire Size (acres)

Percent of Area Burned

0–.25 .25–9.9 10–99 100–299 300–999 1–5,000 >5,000

40

30

20

10

0

Fire Size (acres)

Percent of Fires

0–.25 .25–9.9 10–99 100–299 300–999 1–5,000 >5,000

50

60

40

30

20

10

0

Figure 12—Percent of fires by size

class in red fir and lodgepole pine

vegetation types in prescribed natural

fire zones in Yosemite National Park

between 1972 and 1993.

Figure 13—Percent of total area

burned by fire size class in red fir and

lodgepole pine vegetation types in

Yosemite National Park between

1972 and 1993.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 31

wind, and humidity, but they are also highly dependent on the species

composition, stand structure, and topographic setting of individual plant

associations.

Burning season, aspect, and topographic setting are important components

of fire occurrence and effect in these higher elevation forests as elsewhere. Most

lightning fires are concentrated in the middle to late summer in upper montane

forests. Greenlee (1973) notes that most fires in the Emigrant Basin Wilderness

occurred after July, and Vankat (1985) records 85 percent of all lightning fires in

Sequoia National Park in one study occurring between July and September.

Lightning caused fires also appear to occur with higher frequency on ridges and

upper slopes and on south to west aspects in these forests. Thus, Greenlee (1973)

observes that more than 70 percent of the fires in the Emigrant Basin Wilderness

within a 23-year period lie on south to west aspects. Similarly, over a 63-year

period Vankat (1985) records the highest number of fires in Sequoia National

Park lying on SE, S, SW, W, and NW aspects. Nearly 30 percent of these same

fires occurred on ridge top positions. Fires in Yosemite National Park follow the

same pattern with 55 percent of the lightning fires occurring on SE, S, SW, W, and

NW aspects; furthermore, fires on south and west facing slopes became larger

because 89 percent of the fires larger than 50 acres occurred there. The hotter and

drier conditions of these sites appear to account for these differences (van

Wagtendonk 1986).

Fire intensity in these forests reflects plant community structure and species

composition. John Muir, for example, noted that on calm days of fall in lodgepole

pine forests, fires crept quietly along the ground until a larger lodgepole pine

tree was encountered then the entire tree often burned. This pattern repeated

itself at irregular intervals for “weeks at a time” (Muir 1894). Five studies have

documented differences in fire intensity and severity in upper montane forests.

Pitcher (1987) described variable impacts from fires in three stands of red fir

mixed with western white pine. No evidence was found for extensive crown

fires, but individual trees and groups of trees of about 0.5 ha were killed. Kilgore

(1971) noted that fire in red fir dominated stands had little effect on the species

composition and stand structure. He observed that little crowning took place in

these fires, and although many red fir seedlings and saplings were killed, few

older red fir were affected. Mature lodgepole pine were killed, but lodgepole

pine regeneration was stimulated. Kilgore and Briggs (1972) observed a 452-acre

fire burning in Jeffrey pine over a shrub layer of manzanita. They estimated that

80 percent of the manzanita layer burned, but few pines more than 10 feet were

killed. This fire was extinguished when it reached a moist draw with quaking

aspen, a rocky ridge, a rocky escarpment, and sparsely vegetated bluffs. They

also observed a 115-acre fire spreading slowly in red and white fir with scattered

Jeffrey pine and little understory. This fire was limited in size by a wet draw, a

grassy glade, and fuel discontinuities. Many small trees, snags, and older trees

with open catfaces or decayed interiors were consumed completely, but few

instances were observed in which the fire burned in the crowns. Agee (1990)

noted that variable effects resulting from fire behavior in natural fires burned in

1978 and 1986 seemed to be characteristic of red fir forests. Although much of the

burned areas he observed had moderate severity, areas of high and low intensity

were also noted.

In a study of lower elevation upper montane forests in Sequoia-Kings Canyon

National Park, vegetation patterns were grouped into three categories: open (30

percent cover), closed (60-90 percent cover), and brush habitats (50 percent

cover) (U.S. Department of Interior 1975). Fire effects were highly variable

depending on type of habitat. Fires in open habitats burned with low intensity

and severity. Those in closed stands were more variable and unpredictable with

areas of intense heat and severe damage (especially in areas of fuel buildup)

alternating with areas of low intensity and little damage. Brush habitats
32 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

experienced the highest intensity and damage to conifers particularly on slopes.

In addition to climate, these responses were attributed to differences in cover,

species composition, stand structure, distribution and buildup of fuels, and

topographic setting of each of the habitats. Microclimate was fundamentally

different in each habitat, and burning in general was patchy and related to fuel

continuity. These observations correlate well with the observations of Mutch

(1970) who hypothesized that plant species and communities possess specific

burning properties related to fire adaptations.

Recent prescribed burning programs in the upper montane have confirmed

those observations. For example, fire effects in an August burn on the Stanislaus

National Forest were reflective of plant association. Within a Jeffrey pine/

huckleberry oak association on a south facing slope, over 75 percent of the shrub

layer and most of the smaller conifer seedlings and saplings were consumed.

Scattered large dominants were lightly damaged. Within dense stands of the red

fir and white fir-sugar pine-red fir associations, understory trees and shrubs

were largely consumed in some cases but bypassed in others depending on

factors such as slope position, fuel accumulations, and fire intensity in adjacent

stands. Surprisingly, little effect occurred in stands with pinemat manzanita

understories. Gaps in which all trees were killed and ranging in size as large as

about 1 acre were created in dense stands of the red fir association. Finally, fire

effects in the lodgepole pine/Gray’s lovage association were minor. After

reaching the stand, flame heights lowered and intensity diminished. A month

later, the fire was creeping in litter and fine fuels, but little damage was observed

on trees or most understory species in this stand.

Small-scale fire effects appear to dominate these forests. Evidence for this

view is supported by several sources. First, higher elevations experience shorter

burning seasons and cooler temperatures. In addition, fires in the upper montane

are often accompanied by rain and higher humidities, and they occur in a

fragmented landscape. For example, Potter and others (1992a) found stand sizes

to be significantly distributed toward stands with smaller acreage in the upper

montane. Most fires are therefore small. When fires do reach large size, burning

patterns are patchy, and many relatively small scale disturbances of varying

intensity are created within a stand. Spatial relationships within stands appear to

support this view. For example, many have related the patchy distribution of

different size trees in red fir stands to gap phase regeneration in response to

disturbance (Barbour and Woodward 1985, Gordon 1978c, Hallin 1957, Oosting

and Billings 1943, Parker 1992). Taylor and Halpern (1991) found regeneration,

saplings, and small trees clumped at scales similar to canopy openings in support

of this idea. Finally, distributions of tree size classes in most of the plant

associations presented in this study are similar to an irregular structure or the

reverse “J” shape structure of uneven-aged stands, indicating that gaps have

been filled with regeneration over time, and there is a lack of large scale stand

replacement.

In summary, current knowledge of upper montane fire regimes indicate that

more lightning strikes occur than at lower elevations, and these strikes cause

more fires than at lower elevations. Most of these fires are less than 10 acres;

however, most of the acreage burned occurs in fires of moderate size between 10

and 1,000 acres. Occasional large fires do occur. The intensity and effect of fire in

the upper montane varies with overall burning conditions, but they heavily

depend on the topographic setting and the composition and structure of

individual plant associations burned.

Native-American Influence on Fire Patterns

Humans have influenced the fire regime of these forests for at least the last 10,000

years and perhaps longer (Moratto 1984). Most of the forest stands we see today

originated after 1200 A.D., a time when relatively large, stable Native-American
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 33

populations occupied sites along major streams and tributaries at lower

elevations (Woolfenden 1994). But, the impact of this long-term occupancy on

vegetation patterns is largely unknown at this time.

Relatively little is known about the details of manipulation of vegetation by

Native-American populations at lower elevations in the Sierra Nevada, and even

less is known about higher elevations (Anderson 1993, Lewis 1973). Most

descriptions of Native-American burning are from low elevation areas. Lewis

(1973), for example, notes that little information is available on higher elevation

communities such as red fir and lodgepole pine, and he observes that ”since

plant and animal resources are reduced as altitude increases and growing seasons

shorten we may expect that Indians [sic] affected those environments to lesser

degrees.” Bonnickson (1975) also believes that fires at higher elevations are the

result of escapes from lower elevations. Climatic changes alone have fluctuated

between cool/wet and warm/dry periods several times over the past several

thousand years (Moratto 1984, Pielou 1991, Woolfenden 1994), and this obscures

the effects of Native-American burning patterns even further. Thus, it is difficult

to piece together the specific vegetation patterns that might have emerged from

the interaction of native burning over such a long time period. Most insights

must be gained from circumstantial evidence and inference.

Native-American populations were present and wide-ranging at all

elevations in the Sierra including the upper montane. Because of the heavy

snowpack and short growing season, most use at higher elevations was

undoubtedly seasonal, but abundant evidence of occupation by all Sierra tribes

in the upper montane exists. National Forest archeological surveys consistently

show the presence of native populations throughout the range, and evidence for

use of the upper montane forests is more widespread than expected. Populations

were concentrated away from low elevation permanent village sites to a belt

between 4,000 and 9,000 feet during the summer (Anderson 1993), and well-used

trading routes across the Sierra were established (Anderson 1993, Reynolds

1959). Both John Muir and Joseph LeConte describe contacts made with small

groups of Native-Americans near Mono Pass in the 1870’s on an obviously wellestablished trade route (LeConte 1930, Muir 1894).

Generally, even at higher elevations, if favorable sites for occupation are

located, then evidence of occupation is also found (Balen, pers. comm.). Bedrock

grinding sites are not uncommon in the upper montane, and they were probably

used for typical acorn processing. John Muir (1911), for example, notes the heavy

loads of acorns carried by Native-Americans 60 to 70 miles across Mono pass.

But most likely higher elevation grasses and bulbs were also used as a readily

available food source while the higher elevation sites were occupied (Anderson

1993, Lewis 1973). During sampling for the classification, obsidian flakes and

arrowheads were found at several widely scattered sites in the sample area

indicating movement throughout the upper montane.

Some compelling reasons have been posited to support the idea that NativeAmericans made extensive use of higher elevation sites. First, deer migrate

upward into feeding and fawning areas in the upper montane in early summer.

By summer’s end herds are commonly found at elevations above 6,000 feet.

Second, additional plant materials become available along an elevational gradient

as summer progresses. Flowering often persists into late summer at higher

elevations; whereas at lower elevations, plants have long dried up. Third, the

most extensive meadow systems in the Sierra Nevada lie at elevations above

6,000 feet, and they are prime sources of many food materials. Fourth, high

elevation sites placed Native-Americans in close contact with trading partners

on the other side of the mountains. Finally, the coolness of higher elevations is an

attractive alternative to the heat of a California summer at lower elevations.

Thus, because this evidence shows that Native-Americans were attracted to

higher elevations, then they also likely used techniques learned at lower elevations
34 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

to shape vegetation for their use at higher elevations. Such techniques would

undoubtedly have included the use of fire. However, the details of this burning at

higher elevations is unclear, such as their frequency, size, and timing, and to what

extent such fires supplemented the patterns established by lightning fires.

Many studies have described how native populations used fire as a tool to

control vegetation. Evidence shows that almost every tribe in the western United

States used fire to modify its environment, and the magnitude of such burning in

the Sierra Nevada may have been substantial (Kilgore and Taylor 1979, Lewis

1973). Burning was used to drive game and improve hunting and access;

encourage resprouting, establishment, and production of plants used for food

and tools; aid food gathering; control insects and pathogens harmful to food

supplies; maintain plant community diversity and allow prediction of resource

availability; and to prevent fuel buildup that could lead to disastrous fires

around villages, water sources, and cultivated areas (Anderson 1993, Lewis

1973). Thus, fire was used in an integrated, highly skilled, and ecologically

significant way to shape specific plant communities within the Sierran landscape

as a whole (Anderson 1993, Lewis 1973, McCarthy 1993, Vankat 1977).

Although the use of fire may have been widespread in general, the actual

application often appears to have been directed at very specific plant or animal

communities that could have been quite small in size. Small bands and families

frequented traditional sites where plant or animal resources could be gathered

on a predictable basis for many generations (Anderson 1993). For example, many

of the species collected for food are found primarily in meadow situations at

higher elevations (Anderson 1990, 1993). Vegetation management in these

habitats probably involved tilling by hand, coppicing, and the use of fire. The use

of fire to encourage production of mule ear seeds (Wyethia spp.) has been

described at lower elevations in the Sierra Nevada (Anderson 1993), and it can

logically be inferred that such techniques would also have been used at higher

elevations in the unique communities of mountain mule ears (Wyethia mollis).

Often burning was done to create openings that would increase both plant and

animal resources (Burcham 1974, Lewis 1973). In other cases burning appears to

have been done on a very local scale around areas of long-term residency

(Burcham 1974), and the spottiness and higher frequency of such local burning

probably affected vegetation patterns on a much finer scale than would have

been obtained with natural fire (Lewis 1973).

On the other hand, burning was also applied over larger areas to enhance

hunting opportunities or to encourage development of understory plants within

a general area. If this is accurate then fire use could have covered substantial

areas and created patterns similar to large natural fires. Lewis (1973) notes in a

report on burning for acorn gathering, that no underbrush remained in the

valleys or on the hillsides and that one side of a valley was burned, and then, a

year later, the other side. Reynolds (1959) found that natural ignition alone was

inadequate to explain the vegetation patterns that existed at contact. He showed

that Native-Americans supplemented the frequency of natural fires greatly.

Kilgore and Taylor (1979) concluded that natural ignitions alone were not

adequate to account for the historic fire frequency in mixed conifer forests.

McCarthy (1993) reports that in the south central Sierra Nevada large acreages

were burned over to kill the brush and that in the early days of European

settlement the forest floor was clear and a horse could be ridden anywhere

through the woods. John Muir (1894) also comments on the open patchy nature

of the early Sierra Nevada forests.

In summary, it appears Native-American burning was applied to Sierra

Nevada forests in a highly sophisticated way over thousands of years. Because

evidence shows they inhabited the upper montane forests on a seasonal basis, we

can infer that such occupancy involved the use of practices learned elsewhere,

including the use of fire. The details of such use are relatively unknown, and the
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 35

influence on higher elevation forests is also not known, but the use of fire was

probably planned to accomplish specific results and fire frequencies and

vegetation patterns observed today must include consideration of these practices

along with those described for naturally occurring lightning fires.

Influence of European Settlement on Fire Patterns

Reconstructing fire patterns is difficult from the time of Native-American contact

with European settlers in the 1850’s until the beginning of fire suppression

around 1900 because few reliable records are available. Even after fire

suppression policies were started, record keeping was poor—particularly at

higher elevations. Only in the most recent periods since about the 1930’s have

reliable records been available, and few of these detail the effects of fire on

specific plant communities.

After European settlers became established in the mid-1800’s, they began

using the Sierra Nevada for a variety of purposes. Grazing, in particular, was

common throughout the range, and herders used fire for many of the same

reasons that native populations did (Kilgore and Taylor 1979). Muir (1894)

comments that “running fires are set everywhere (by sheepherders),” and “the

entire forest belt is thus swept and devastated from one extremity of the range to

the other.” Contemporary newspaper accounts document fires as large as 30,000

acres that were set by sheepherders, and many felt that the greatest percentage of

the large destructive fires in the Sierra Nevada were caused by sheepherders

“during the thirty years preceding the establishment of the Forest Reserves”

(West 1935). Fires were usually set in the fall as the herds were removed from the

range. This practice was adopted to improve access and encourage sprouting

and establishment of favored species the following year.

The details of the use of fire, its influence on forest composition and structure,

and how such burning combined with simultaneous grazing interfaced with the

decline of Native-American burning or supplemented lightning fires is unknown

at this time. By analyzing fire scars, Kilgore and Taylor (1979) estimated that the

fire record for the period between European settlement and about 1875 was

similar to the previous 165 years. This work supports the view of Vankat (1977),

who concluded that much of the burning done by sheepherders was a

continuation of burning by Native-American populations.

Fire suppression policies by government agencies became widespread in the

early 1900’s. These policies became effective at lower elevations soon after their

inception, but because of the problems of access, the effect was not as immediate

at higher elevations. Kilgore (1971) notes, for example, that early fire suppression

efforts were directed towards the lower elevation mixed conifer types, and he

estimates the ecological importance of fire suppression efforts before 1940 was

questionable at higher elevations. Kilgore and Taylor (1979) and DeBenedetti

and Parsons (1979) found that fire suppression became effective at higher

elevations in the mid 1920’s in Sequoia National Park, and Taylor (1990) estimates

effective fire suppression around 1926 in upper montane forests in the southern

Cascades. Currently, throughout most of the National Forest and private lands

in the study area, fire suppression policies remain in effect; however, on most

National Park lands a prescribed natural fire policy is now being used at least at

higher elevations.

Studies have indicated that the impact of fire suppression policies has

resulted in an increase of the amount of shade tolerant species. The loss of

quaking aspen stands to shade tolerant conifers in many parts of North America,

including the upper montane, has been attributed to fire suppression (Kauffman

1990). Kilgore and Taylor (1979) relate the increase of white fir understory in the

sequoia-mixed conifer forest type to the absence of fire. Vankat and Major (1978)

relate increased tree density at lower elevations in the upper montane to fire

suppression, but at higher elevations increased tree density appears to be the
36 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

result of reduced grazing pressure. For example, mixed, white fir and giant

sequoia stands showed increases in white fir density and cover since the initiation

of fire suppression. Red fir stands also showed an increase in red fir density and

cover, and, where it is associated with lodgepole pine, a decrease in lodgepole

pine cover and density. These results agree with other studies that have examined

changes in these forests since fire suppression policies were enacted (Biswell

1989, Gruell, pers. comm., Heinselman 1981, Kilgore 1971, Kilgore 1973, Kilgore

1981, Rundel and others 1977, Van Wagtendonk 1974, Weatherspoon and others

1992). On the other hand, in lodgepole pine communities at higher elevation,

increases in lodgepole pine density and cover appeared to be related to a decrease

in grazing pressure. In low density communities, such as those dominated by

Jeffrey pine, little change was observed.

Thus, changes in upper montane forests since the adoption of fire

suppression policies vary by the species composition and density of a particular

plant association as well as the temporal scale. Because many forested stands in

the upper montane are dominated by shade tolerant species, changes more often

involve modification of density rather than species replacement. Stands

dominated by shade intolerant species, especially those of naturally low density,

also seem to maintain their species composition for long periods. Stands of

mixed species appear to be most subject to change in species composition, and

generally shade tolerant species have been favored in the relatively short time

since suppression became effective in these higher elevations.

In addition to possible changes in species composition, fire suppression has an

effect on fuel loads and stand structure that influences fire behavior. Little work,

however, has been done on these relationships in the upper montane. This

classification report attempts to describe the density and distribution of coarse

woody debris as it currently exists. However, information to compare these values

in a historic sense is unavailable; thus, the results of this study are cast against a

background that includes both recent management practices as well as climatic

changes of the past several thousand years. In a general way, fire suppression has

probably increased the fuel loads and increased the potential fire severity in dense,

closed canopy plant communities in the upper montane. The accumulation of fine

fuels and larger logs at the surface and the creation of a fuel ladder into the crowns

of larger, older trees has probably increased the possibility of larger and more

intense fires in current forests. In more open communities, probably little has

changed in the time fire suppression has been in effect.

Grazing

Grazing history in the upper montane can be divided into two time periods:

before and after formation of the Forest Reserves. The period before formation of

the Reserves generally encompasses the time from occupation by the Spanish in

the late 1700’s through the early 1900’s, while the second encompasses the time

between formation of the Forest Reserves and the present. Grazing practices and

impacts differed substantially between these two periods. From an ecological

viewpoint, the most significant grazing use probably occurred between the

1850’s and the 1900’s.

Grazing began as soon as the Spanish arrived. Most of this use was limited to

coastal areas in conjunction with mission activities, and it only spread gradually

into the interior valleys. The great influx of grazing use in the Sierra Nevada

began with the gold rush of 1849. Cattle use, for example, increased from an

estimated 250,000 head in 1850 to 1,000,000 head in 1860, and by 1862 the number

was 3,000,000. An estimated 40 percent were located in the Sacramento and San

Joaquin Valleys adjacent to the range. Sheep became important for food and

wool in the mining camps between 1852 and 1860, and flocks expanded and

eventually peaked in the mid-1870’s at about 6,400,000 head statewide (Ratliff

1985). In 1880, 2,864,000 sheep were estimated in the Sacramento and San Joaquin
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 37

Valleys alone (West 1935), and a few large ranches located in the central valley

had herds of 100,000 to 200,000 sheep.

Grazing use was limited to the central valley and foothills until about the

1860’s. In 1861, for example, cattle were first introduced to the current SequoiaKings Canyon National Park (Vankat and Major 1978), and the droughts of

1862-63 and 1876-77 added impetus to summer grazing in the mountains (Ratliff

1985). Grazing increased dramatically, and while cattle use was widespread,

sheep soon became dominant (Ratliff 1985, Vankat and Major 1978). Often great

circuits were made with sheep from the south being moved up the eastside of the

range early in the year, across the many passes during the summer, and down

the westside to the central valley in the fall. On the westside great numbers were

driven across the crest throughout the summer and then returned over the same

route to the central valley in the fall.

Few records exist to document the early numbers of sheep and cattle present

during summer seasons in the upper montane, but the herds must have been

abundant. In the southern Sierra Nevada many large flocks of sheep came from

Orange County in southern California and the large ranches in the San Joaquin

Valley. These flocks were moved into the mountains from the eastside as soon as

melting winter snows permitted. Similar patterns were repeated on the westside.

John Muir (1911) noted that in the 1870’s large flocks of sheep were moved

upcountry gradually as the snow melted, and they often spent several weeks at

the best places until the snow at higher elevations cleared. Muir travelled with a

flock of more than 2,000 sheep into Tuolumne Meadows in 1873, and while

camped in the area he noted the presence of several other camps with large

herds. One camp on Porcupine Creek had “thousands of sheep” in it. He also

observes (1894) that “incredible numbers of sheep are driven to mountain

pastures every summer. Everything is eaten and the woods are burned.” LeConte

(1930) reported the presence of 12,000 to 15,000 sheep in Tuolumne Meadows in

August of 1870, and other studies acknowledge that the numbers of sheep must

have been in the range of hundreds of thousands to a million (McKelvey and

Johnston 1992).

Throughout the 1880’s, sheep were driven to the mountains “by the hundreds

of thousands and the policy of feed at any cost was well established” (West 1935).

During the drought of 1897-99 the North Fork of the Tule River area was grazed

intensively by about 200,000 sheep, and as late as 1900 this number of sheep were

still grazing in the Sequoia-Kings Canyon region (Vankat 1970).

Early grazing was unregulated. Herders took advantage of any available

forage at any time to graze their stock. During drought years high mountain

forage was used intensively by a wide range of stock including cattle, sheep,

milk cows, horses, goats, and pigs. Early accounts of Sequoia-Kings Canyon

National Park document that most of the park was used to at least some extent,

and most use was, in fact, intensive (Vankat and Major 1978). Entry onto the

range too early caused as many problems as excessive stocking, and often several

herds used the same routes into the mountains over a period of time. The first

herd fed on immature shoots, the next herd chewed these even closer to the

ground, and by the time the final herd arrived the ground was stripped of cover

(Eldorado National Forest 1912).

Overgrazing during this time appears to have been widespread, and erosion

resulting from these practices was extensive. “Tales of damage to resources were

to become legendary” (Ratliff 1985). Burcham (1957) believed that changes in

successional patterns on valley and foothill range lands provided clear indication

of a downward trend in the range resource, particularly soil productivity.

Commenting on sheep use, Muir (1894) observed that “their course is ever

marked by desolation.” Sudworth (1900) complained about difficulty finding

feed for pack stock: “the forest floor is clean” with a “total lack of grass forage.”

Conversely, he recorded “that there was (formerly) an abundance of perennial
38 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

forage grasses throughout the forests of the territory.” In 1909 Eldorado National

Forest records note: “it is generally conceded that the mountain ranges have

greatly deteriorated in feed value since the country has been used for grazing

purposes,” and further that “it is difficult to understand how badly this range

must have been used.” Mud slides in the South Fork of the Kern river, the San

Joaquin river, and the Kaweah river during the 1860’s and 70’s have been

attributed to overgrazing.

After formation of the Forest Reserves and National Parks in the 1890’s and

early 1900’s regulation of grazing practices commenced and use began to decline.

Sheep grazing ended in the National Parks by the 1900’s, and effective control of

grazing through issuance of permits began with the formation of the National

Forest System in 1905 (Ratliff 1985). Early efforts at regulation were often

ineffective, but control was gradually gained. Fences were few, and early day

enforcement was difficult because of terrain and limited personnel. Stock from

private in holdings within and adjacent to National Forests grazed largely

unrestricted on National Forest lands, and even permitted use on National

Forests crossed the borders of adjacent National Forests unless patrolled

adequately (Eldorado National Forest 1912).

Grazing is no longer permitted on National Park lands other than pack stock

used in administration work and recreational travel. On National Forest lands

use has decreased steadily since formation of the National Forest System,

although numbers in individual years have varied in response to a variety of

conditions. For example, most ranges were overstocked by presidential request

to supply more meat during World War I. Conversely, hoof and mouth disease

decimated stock levels on the Stanislaus National Forest during 1924, and no use

was permitted during 1925 (Grace 1965). A substantial downward trend in cattle

use began in 1925, and it has continued to the present as a result of higher costs of

operation, difficulty in finding skilled range labor, changes to feedlot operation,

and relinquishment of permits by larger operators. Sheep use declined from a

peak during World War I to extremely low levels at present. Currently, numbers

of all stock are at roughly 20 to 40 percent of those present at the time of

formation of the National Forest System, and practically all of this is used by

cattle and horses.

Although the numbers of livestock have been reduced greatly and range

conditions are improving in general, the ecological impact of nearly 130 years of

grazing, a major portion of which was concentrated in the 40 year period from

1860 to 1900, can only be speculated. Livestock grazing has been an event never

before encountered by these forests. Changes to the landscape between the

1850’s and early 1900’s must have been particularly dramatic. Many studies

show that, from the time of Spanish settlement until formation of the Forest

Reserves, grazing completely changed the herbaceous layer of the grasslands

and foothill woodlands (Burcham 1957, Vankat and Major 1978). Most detailed

accounts and analysis, however, are from lower elevations in the central valley

and foothills. Whether similar changes also occurred at the higher elevations of

the upper montane is uncertain. For example, Burcham (1957) notes that

replacement by introduced species at higher elevations apparently has not

progressed to the same extent as at lower elevations, and he believes this is

probably due to climatic differences. Vankat and Major (1978) believe that

increased tree densities in the blue oak, lodgepole pine, and subalpine forests of

the region resulted from reduction of grazing pressure in the early 1900’s.

Leiberg (1902) records areas that had been heavily grazed and subsequently

contained 10,000 to 15,000 red fir trees per acre.

Some observations from the field may be helpful in understanding changes

that may have occurred in the upper montane. First, more than 80 percent of all

sample sites in this study outside of the National Parks showed the presence of

livestock. This condition simply means that while cattle and sheep tend to
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 39

congregate in riparian areas, they still range widely in the upland portions of the

forest. Thus, the grazing patterns observed during sampling probably occur over

a broader area. This theory is further substantiated with palatability estimates

(U.S. Department of Agriculture 1969). Cattle and sheep generally do not feed on

conifers and many of the shrubs in the upland portions of the upper montane.

White fir and quaking aspen are the only two tree species in which browsing—

particularly on seedlings—was consistently observed. Lotan and Critchfield

(1990) also note that sheep browse new growth of lodgepole pine in the spring

and “nibble needles and small branches if other feed is not abundant”; however,

widespread evidence of such browsing was not observed in current stands

containing young lodgepole pine. Most of the shrubs that are browsed have

regeneration strategies such as sprouting and long-term storage of seed in the

soil that permit rapid reestablishment after disturbance. Further, they tend to

grow in dense clumps or patches and discourage browsing except at the edges.

Many of the common species in the herbaceous layer are not palatable to

livestock.

Of the herbaceous and graminoid species observed in the study, the

overwhelming majority are native annuals and perennials. Introduced species

do not dominate the upper montane. This condition would indicate most native

species persisted under the early grazing practices, and that more than isolated

refugia would be involved. In other words, recovery was sufficient each year to

provide enough feed to carry livestock in succeeding years without depleting

long-term seed availability or sprouting capability. Such recovery must have

come from propagules that remained on or adjacent to most sites in sufficient

numbers to revegetate sites annually.

Thus, the assemblage of species in the upland landscape today suggests that

at least enough residual population of native species persisted to permit

reestablishment once the grazing pressure eased. The spatial distribution, relative

densities and cover values, the ratio of annuals to perennnials, and the genetic

makeup of the historic assemblage are currently unknown. And, of course,

species now missing from the landscape or that were pushed closer to extinction

because of the grazing pressure are unknown. But most of the species currently

found in the study area have been subject to other disturbances for millenia, and

they have developed a degree of plasticity in response to changing environmental

conditions that allows persistence despite unusual events.

Timber Harvest

Timber harvesting began as soon as humans arrived in the Sierra Nevada.

Native-Americans and early Spanish settlers used whatever trees were available

for construction, tools, and fuel. Such use was probably restricted primarily to

lower elevations, and it was probably not significant in comparison to existing

growth rates of the time. Heavy demands for wood began with settlement

during the discovery of gold in 1849: early timber harvesting centered around

the mines and towns that grew with them. As demand increased, harvesting

extended further and required more sophisticated means to transport raw

materials to centers of production. By the mid-1920’s extensive railroad logging

was in place in most of the lower and mid-elevations of the Sierra Nevada, and

large acreages were harvested. During the 1940’s technology changed from

railroad logging to the use of tractors and trucks. Roads and harvesting extended

even further. However, in most cases harvesting operations did not begin on the

lands in the upper montane until the mid-1950’s.

Early harvesting used sanitation and salvage cutting, release cutting, and

improvement cuttings based on the concepts of “poor risk” (Salman and

Bongberg 1942). Harvesting covered large areas since yield per acre was generally

low using these cutting methods, and emphasis was placed on roading the
40 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

ownership for future management. Although pine species were favored in

cutting, the most obvious changes in stands during this time were structural as

many of the larger trees were removed, densities were lowered, openings were

created, large logs increased, and snags were reduced.

By the late 1960’s road systems were generally established, and more formal

silvicultural systems were used. On better sites even-aged silviculture used the

clearcutting method. In suitable stands thinnings were conducted, and in many

adjacent stands salvage and sanitation and improvement cuttings were repeated

depending on stand condition. On poorer sites sanitation and salvage methods

were generally used.

In clearcuts, essentially all the trees were removed, the debris resulting from

the logging operation, including large logs and snags, was disposed of, and sites

were then planted, in most cases, to Jeffrey pine. Few clearcuts were larger than

25 to 30 acres, and most were smaller than 10 acres. In stands that were thinned,

densities were lowered, but other structural features and species composition

remained little changed. The practice of removing all large logs and falling all

snags in logged areas to lower fire hazards also began during this time.

In many of the clearcuts survival of planted Jeffrey pine was spotty, and

species from adjacent stands seeded the sites. In some cases red fir, white fir, and

Jeffrey pine became established naturally, and often lodgepole pine dominated

the early regeneration on more mesic sites. Where Jeffrey pine planting was

successful, particularly on south facing slopes or drier sites, plantations as old as

20 years now exist. Structurally, these successfully regenerated sites will emerge

as even-aged stands in the immediate future. Where regeneration was

unsuccessful sites are often occupied with persistent layers of shrubs, herbs, or

grasses. Little clearcutting has been done at the highest elevations of the upper

montane, but in those areas where it has occurred, the same practices were often

followed, and most commonly, regeneration of tree species has been unsuccessful.

More recently, clearcutting has been less emphasized in the upper montane.

Although harvesting under formal, uneven-aged silvicultural systems has been

little tried, shelterwood cutting has been substituted for clearcutting where stand

conditions permit, and the practice of removing all large logs and snags has been

modified to meet wildlife needs. Clear patterns of regeneration success with the

shelterwood method in the upper montane have not yet emerged, and so it is

difficult to foresee long-term changes in species composition and structures

under this cutting practice. Other methods such as sanitation and salvage and

improvement cuttings continue with the exception that large logs and snags are

retained at higher levels for wildlife needs. The general consensus seems to be

that intensive harvesting in the upper montane has been of insufficient duration

and scope to have made substantial long-term changes in the species composition

and major structural elements of these forests. Field observations made during

this study confirm this view.

Methods

Sampling

Before sampling, a preliminary reconnaissance of each major geographic region

in the study area was performed to recognize variation in species composition

and environmental setting of the more obvious plant communities and to guide

placement of sample sites. During this initial phase, it became evident that the

presence of red fir in the stands could be used in most cases to differentiate the

upper montane from the lower montane and subalpine zones. The presence of

this species was then used to establish the upper and lower elevational limits of

each major area that was sampled.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 41

Sampling was performed in late-seral stands of homogeneous cover and

species composition with no evidence of recent disturbance. Tree cover was

generally greater than 10 percent. Sites were selected based on variation in

species composition, life form, structure, geology, soils, and general

environmental setting to provide the basis for estimating species response to

environment.

Individual sites were selected “subjectively without preconceived bias”

(Mueller-Dombois and Ellenberg 1974). Although this method loses some of the

strength of statistical interpretation that random and systematic sampling can

provide, it is a practical solution to sampling the variation present in vegetation

over an area as large as the study area. Initially, 75 to 100 samples were taken

within each of the westside forests to develop an understanding of the nature

and variation of the plant communities present. Refinements and adjustments

were made in the sampling strategy as field work progressed, and plant

communities that needed further sampling to build redundancy or provide

definition became the focus for subsequent rounds of sampling. The final

classification includes 757 sample sites distributed over the study area. Sampling

generally followed an elevational transect using existing road and trail networks

to provide coverage. Sample sites were well-separated to ensure that samples

were independent and that vegetation patterns were similar over larger

geographic areas and did not represent localized phenomenon.

The information collected at a particular site focused on five main areas of

concern: location, environmental setting, geology and soils, species composition

and cover, and productivity. Thirty variables described the location and

environmental setting, 17 described the geologic setting and soil profile, 10 were

used to describe the tree layer, and 4 variables were used for each of the shrub,

forb, and grass layers. Eight variables describing site productivity were calculated

as described in the USDA Forest Service’s Forest Inventory and Analysis User’s

Guide (1992a). In addition, 4 derived variables were developed from the raw data

taken with each sample. In total, 81 variables were measured or developed for each

sample site (appendix C). In addition, cover and abundance values were recorded for

each plant species. Cover values for 104 species were used in the final analysis.

The first derived variable, solar radiation index (SRI), was a measure of the

solar energy incident on a site. It was determined using tables by Frank and Lee

(1966). The SRI was based on measures of latitude, aspect, and slope at each site.

The second, stress index, was patterned after the topographic relative moisture

index (Parker 1982). It combines SRI, the available water holding capacity (AWC)

of the soil profile, elevation, and slope position. Conceptually, this index varies

anticipated moisture stress to reflect changes in solar radiation levels and

available water holding capacity. It also adjusts for elevation differences

reflecting the adiabatic cooling effect of the atmosphere, and it accounts for slope

position by assuming that moisture stress is reduced the further downslope a site

is located due to subsurface water flow. The equation used for stress index is

described in appendix C.

The remaining derived variables were measures of plant species diversity:

Simpson’s lambda and three Hill numbers (Ludwig and Reynolds 1985).

Simpson’s index varies from 0 to 1 and is based on the probability that two

individuals drawn at random from a population belong to the same species. Hill

number “N0” is the number of all species in a sample. Hill number “N1” is the

number of abundant species, and Hill number “N2” is the number of very

abundant species.

Description of environmental setting, composition and cover of shrubs, forbs,

and grass, and geology and soils were based on samples from a 

1⁄10-acre circular

plot. Tree species composition, density, diameter distributions, and volume

estimates were obtained from variable radius plots located in a 3 or 5 point “L”-

shaped cluster situated around the centerpoint of the 

1⁄10-acre plot in accordance
42 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

with forest inventory standards of the Pacific Southwest Region (U.S. Department

of Agriculture, Forest Service 1992a). Snag species and diameters were measured

as part of the variable radius plot sample for the tree inventory on 604 sample

sites. In addition, during some years of the sampling it was also possible to

obtain additional information on snags and downed logs. During 2 years, snags

smaller than 10 inches DBH and logs smaller than 10 inches diameter on the large

end were measured for height or length, species, and decay class on the 

1⁄10-acre

plot. Snags and logs larger than 10 inches were measured on a 

1⁄2-acre circular

plot for these same variables. This data set provided information from 180

sample sites on 881 snags and 1,640 logs.

A separate data set was constructed to develop an understanding of climate

relationships in the study area. Precipitation data came primarily from the

monthly normals of temperature and precipitation from 1951 to 1980 (National

Oceanic and Atmospheric Administration 1982). In addition, the California Data

Exchange Center (CDEC) database was accessed to identify stations that had

substantial long-term records but did not meet the criteria for a 30-year normal

due to missing records within the period. From these sources, 72 stations covering

both the westside and eastside were selected for precipitation records, and 43

were selected for temperature records. Snowpack and water content information

was obtained from the California Cooperative Snow Surveys from 1941 through

1990. Records were selected for those drainage basins in the study area. In total,

11 basins from the American to the Kern River covered the westside, and 5 basins

from the Truckee to the Owens River covered the eastside. In the 16 drainage

basins, 193 snow courses were represented.

Precipitation and temperature records are scant at higher elevations,

resulting in difficult analysis of the transition from rain to snow. To capture as

much information as possible from the sparse data and to provide a more local

perspective on precipitation and temperature, the study area was divided into

subregions for analysis. Westside stations were divided at latitude 37°20'. to

illustrate differences between north and south. All stations east of the Sierra

Nevada crest were combined as the eastside subregion.

Data Analysis

Overview

Data analysis followed a concept of successive refinement. Essentially it involved

examining the data first from a broad perspective and then on successively finer

scales as the analysis proceeded. Typically a “cycle” of analysis began with an

ordination or classification that would be examined for samples or species that

clustered together. These clusters formed the basis for testing differences in

environment through gradient analysis. If the environmental gradients

separating clusters were substantial enough, the samples were separated and the

process was repeated with each of the clusters to either further refine that cluster

or define new clusters.

Ordination and classification attempts to summarize community structure in

low dimensional space. Typically, relationships between samples or species are

shown on one or two axis coordinate systems. Ordination attempts to portray the

individuality of each stand; whereas classification groups individual stands into

categories (Mueller-Dombois and Ellenberg 1974). Both techniques were used to

identify samples with similar species composition, show relationships between

samples and species, summarize redundancy in the data set, and identify outliers.

Gradient analysis attempts to uncover the relationships between species composition

and environment by assuming that species integrate environmental variables and

can be used to understand environmental relationships on specific sites.

The computer programs used in ordination and classification were primarily

DECORANA (Hill 1979a) and TWINSPAN (Hill 1979b). DECORANA is an
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 43

ordination technique based on reciprocal averaging with detrending and axis

rescaling. TWINSPAN is a hierarchical, divisive classification technique. Both

programs are robust in their handling of complex data sets, and, in the present

case, similar patterns and relationships generally emerged from the use of each

technique. The Pacific Southwest Region’s series of computer programs known

as FIA (U.S. Department of Agriculture, Forest Service 1992a) and the

PROGNOSIS stand model (Wykoff and others 1982) were used to estimate stand

inventory attributes such as stand volumes, density, stocking levels, diameter

distributions, and site index. Statistical analysis performed to understand

gradients used the BMDP series of statistical software programs (Dixon 1990).2

The methods used in sampling for community classification limit statistical

comparisons that can be made. Large data sets compensate for this in some

degree, but analysis performed to determine gradients must be considered

exploratory in nature (Jongman and others 1987). Also, commonly used data sets

often contain variables with highly skewed distributions, and useful data

transformations cannot be made in many cases. In addition, many of the variables

used are nominal or categorical rather than continuous; consequently, no single

statistical procedure was used throughout the analysis. Both multivariate and

univariate techniques were used depending on the questions explored at a

particular stage of analysis.

An approach that was consistently used in gradient analysis began with the

examination of histograms and contingency tables to understand distributions of

the data. Data transformations would then be performed on continuous variables

as needed, and this would generally be followed by multivariate analysis by

using principal component analysis, multiple regression, and discriminant

analysis. Univariate techniques such as analysis of variance (ANOVA) were used

to compare differences between continuous and categorical variables or between

groupings of continuous variables. Non-parametric chi-square evaluation of

frequency tables was used to test the goodness of fit of categorical variables. An

exhaustive list of comparisons and their results will not be presented. Examples

are presented to illustrate use of particular techniques during the analysis.

The most commonly used data transformations were logarithmic for bare

ground, surface gravel, surface rock, overstory age, and litter thickness. Natural

logarithms were used in transformation of forb, grass, and shrub cover, surface

horizon depth, and coarse fragment content. Arcsin square root transformations

were useful for litter cover and SRI. All subsets regression was used and results

were evaluated using the adjusted R square and the standard error of the

estimate. Jacknife results were used to evaluate the classification matrix from

stepwise discriminant analysis. Statistical significance was assessed at the 5

percent level of probability. The F test in conjunction with the Tukey studentized

range method for pairwise mean comparisons were used to evaluate significance

in the ANOVA model. Levene’s test was used to compare equality of group

variability, and the Welch and Brown-Forsythe tests of significance were used if

the Levene test indicated group variance was not equal. Yates corrected chisquare was used in evaluation of frequency tables.

Procedures

The first phase of analysis emphasized understanding the environmental

gradients present in the study area by using information from all sites regardless

of species composition. The intent was to uncover broad scale relationships in

the environment that could provide insights during classification. This phase

began by examination of a correlation matrix to identify important linear

relationships among continuous variables. The matrix, for example, showed

correlation coefficients greater than 0.50 between AWC and subsoil coarse

fragments and between AWC and soil depth.

2 Trade names or products are

mentioned solely for information and do not imply endorsement by the U.S. Department of

Agriculture.
44 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Principal component analysis was then used to identify which group of

variables were strongly correlated and accounted for most of the variation

observed in the data. These groups, or factors, were retained so that collectively

they accounted for less variance than a single variable. As an example, factors

describing productivity and soil moisture relationships accounted for more than

50 percent of the variation between all factors. The variables underlying each of

them include:

Factor 1 Factor 2

(Productivity) (Soil Moisture)

Available water holding capacity Available water holding capacity

Total basal area Topsoil coarse fragments

Total vegetative cover Subsoil coarse fragments

Bare ground Slope

Surface gravel Total soil depth

Slope position Surface rock

Total forb cover

Total soil depth

Selected variables (such as AWC) were then explored in more detail through

multiple regression to highlight which group of variables best explained the

variation in the selected variable. For example, variation in AWC could be

described (adjusted R-squared = 0.62; S.E.= 0.89) through a combination of

elevation, total basal area, total forb cover, total soil depth, topsoil coarse

fragments, and subsoil coarse fragments.

ANOVA was then used to examine relationships between continuous and

categorical variables. For example, AWC was compared to topsoil textures, and a

significant difference (F = 64.8; df = 4/294) was obtained between sandy and

loamy soil textures. Finally, comparisons were made between categorical

variables using the chi-square statistic. As an illustration, soil textures were

compared to parent material, and granitic and cindery soils were found to

contain significantly higher proportions of sandy soils than those derived from

other parent materials in the study area (chi-square statistic = 110.5; df = 8).

The analysis was repeated for geographic subregions of the study area as a

way of identifying environmental differences between each subregion. Division

into subregions was based on differences in species composition and

environment that were noted during sampling. The westside was separated from

the eastside at the crest of the range, and the northern portion of the westside

was separated from the southern at latitude 37°20', or roughly an east-west line

just north of the Kaiser Wilderness on the Sierra National Forest near Huntington

Lake. In this comparison stepwise discriminant analysis was substituted for

multiple regression because interest at this point was in identifying

environmental differences between subregions. Samples from the westside were

compared to those from the eastside, and those from the northern portion of the

westside were compared to those from the southern. As a result of this analysis,

for example, AWC was found to be significantly higher on westside samples

than on eastside samples (F = 10.2; df = 2/645).

Next, the entire set of samples were classified, based on floristic composition,

with TWINSPAN. The data set was first “weeded” of species occurring less than

three times. In subsequent iterations, species that seemed to have little affinity

for any classified group and thus provided little information to the classification

were also eliminated. The classification was finally based on 104 species. From

this initial classification, several species groups emerged that were similar in
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 45

floristic composition and defined the major plant communities in the study area.

This effort provided insights into the major species that influenced the

classification.

A subsequent classification and ordination was then performed by subregion

on just the tree and major shrub species. This examination used trees and shrubs

because they were major elements of the initial classification. They are longlived, able to capture site resources and dominate stands, relatively resistent to

minor disturbances, and are believed to reflect major environmental differences

reasonably well. The intent was twofold: to separate sample sites based on tree

and shrubs as a basis for defining communities to the series and subseries level;

and to examine whether these species displayed similar environmental responses

in each subregion. To assist in this second objective, an ordination was performed

to provide values or “scores,” on the basis of weighted average species cover

values, for each sample site. These values were used in indirect gradient analysis

to examine relationships between species distribution and environment by

subregion. Results were then compared across subregions. In this way the major

environmental differences expressed by cover of tree and shrub species were

identified and could be used in refinement of the classification.

The analysis continued by examining each series separately and in detail

using a concept of progressive fragmentation (Peet 1980). Samples that occurred

in series that were identified in the previous classification were separated from

the larger data set and classified and ordinated separately. For example, samples

that had originally been grouped based on the presence of a characteristic species

such as Jeffrey pine and considered to represent the Jeffrey pine series were

isolated and reclassified. The result was a refinement in classification of the

series that highlighted species groupings and provided the basis for further

subdivision of the series into plant associations. The Jeffrey pine series might

thus be characterized by sites with huckleberry oak and those with greenleaf

manzanita in the understory as proposed plant associations within the series.

Proposed plant associations identified in this way were tested for differences

in environment concurrently with ordination and classification. Samples within

a series were generally first examined by comparing ordination scores to

distinguish overall gradients underlying the series. Generally, gradients

expressed by linear relationships of species to environment within a series were

weak. Potential associations were often environmentally unique from others in

the series, but these differences were not expressed along the continuum

described by the ordination scores. Univariate comparisons through ANOVA

and chi-square evaluations often provided the most valuable understanding of

differences between tentative plant associations. If an association was considered

sufficiently homogeneous in species composition and different from others in

environmental conditions, it was removed from the data set, and the process was

repeated with the remaining samples if necessary. Further classification ceased

when species composition and environmental conditions were not considered

sufficiently unique, or too few samples remained. Potential plant associations

were generally not divided into smaller groups if less than 10 samples remained.

In those few cases where less than 10 samples remained, scientific judgement

was used to determine if the association existed but was simply dispersed on the

landscape and difficult to sample.

The final phase of analysis compared environmental conditions typified by

some of the more common species. This phase was a separate analysis from those

performed for classification. It was designed to examine autecological

relationships on a broad scale for these species (appendix D). The analysis involved

examining environmental differences for samples with the species present versus

those in which the species was absent. This analysis provided a basis for

considering if a species reflected unique site conditions and could be used to

characterize specific plant associations. Forbs and grasses were tested using a
46 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

presence/absence approach while trees and shrubs were tested generally using a

cutoff value of 5 percent cover for the species. In other words, samples that

contained more than 5 percent cover of a tested tree or shrub species were

compared to those that contained less than 5 percent of the species. This level

was chosen based on experience indicating that levels above this point showed

species that appeared to reflect definite changes in both species composition and

environmental condition. The small size and wide distribution of many of the

forbs and grasses, on the other hand, indicated presence/absence as a more

appropriate measure.

Results

General Relationships

Several patterns were found in the data that are important in understanding the

overall physical setting of the study area. Although these general patterns are

not consistent across all plant communities as the descriptions of individual

plant associations illustrate, they can be used as a reasonable “initial

approximation” of conditions observed on a specific site.

First, important relationships were observed between measures of

productivity, site openness, and soil characteristics. Stocking levels, vegetation

cover, measures of site openness (bare ground, surface gravel, surface rock, and

litter cover), and soil characteristics such as AWC, soil depth, and soil

temperature tend to be highly correlated. In general, sites with shallow soils,

lower levels of AWC, and warmer soil temperatures are reflected in lower tree

densities, less forb cover, and higher shrub cover. Surfaces on these sites are

characterized by higher levels of bare ground, gravel, and surface rock.

In addition, soil coarse fragments and soil depth influence AWC and

moisture stress. As might be expected, rocky sites with large amounts of soil

coarse fragments or sites with shallow soil depths have lower water holding

capacities and higher levels of moisture stress.

Next, a general trend was noted of increasing elevation as latitude and

longitude decrease. Both latitude and longitude are important in understanding

changes in plant communities correlated with elevation. The rise and subsequent

fall in elevation from west to east across the crest is obvious; however, there is

also an increase in elevation of upper montane forest communities from north to

south. Thus, similar plant communities occupy higher elevations on the eastside

as compared to the westside, and they also occur at higher elevations in the

southern than in the northern end of the Sierra Nevada. This rise in elevation

appears to be nearly 500 feet per degree of latitude on both the westside and

eastside. A 3° change in latitude can result in almost 1,500 feet of elevation

difference up and down the range for the same plant community. Other broad

scale effects are increases in soil coarse fragments and a general decrease in AWC

and productivity with increasing elevation.

SRI, which is a measure of the radiant energy received at a particular site, is

strongly correlated with aspect and, to a lesser degree, slope. Because aspect,

slope, and latitude are components of the SRI, a correlation between these

variables would be expected; however, the strong correlation with aspect

indicates aspect can be used as a reasonable approximation of SRI at these

latitudes, and it can be used to understand the typical north-south aspect changes

in vegetation that is characteristic of these forests. Vegetation on steep, north

facing slopes receives substantially less radiant energy than flatter or more

southerly facing stands. Examples of this relationship occur in communities

containing mountain hemlock that often occupy north facing slopes as compared

to Jeffrey pine communities that commonly occupy south facing slopes.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 47

Important relationships were also found between certain soil properties,

slope position, and slope steepness. As might be anticipated, soil depth increases

as sites are located progressively further down the slope or as benches are

encountered. Similarly, AWC tends to increase as moisture stress decreases with

increasing soil depth and location on lower slopes and benches. Slope steepness

also influences soil moisture relationships. Steeper slopes in these forests tend to

have shallower soils with lower AWC and higher moisture stress. In addition,

soil textures in both surface and subsurface horizons are significantly more

sandy on slopes greater than 40 percent while they are more loamy on slopes less

than 20 percent. Sites that occupy steep slopes can also generally be expected to

have excessive drainage as compared to those that occur on shallower slopes.

Generally, stands that appear to be naturally open with high proportions of

bare ground, gravel, or surface rock, or those with a substantial shrub component,

lie on southerly aspects, occupy steeper slopes, or that occur in upper slope

positions can be expected to have lower productivity and vegetative cover. The

open conditions of these plant communities reflect the shallow soils, excessive

drainage, lower AWC, warmer soil temperatures, and higher levels of moisture

stress that is often present.

Parent materials also show important correlations with soil characteristics.

In these forests, granitic soils have high proportions of sandy soil textures and

drainage is often excessive. Even though subsurface horizons are often gravelly,

cobbly, and stoney, coarse fragments are generally lower than soils derived from

other parent materials. Soils derived from pyroclastic materials, such as the

cinder deposits around Mammoth Mountain, have significantly lower levels of

AWC resulting from sandy textures and high proportions of coarse fragments in

the form of gravels throughout the profile. These soils also tend to be excessively

drained; they have higher summertime soil temperatures, and they are generally

less productive. Soils that develop from metamorphic parent materials also have

lower AWC. This appears to result from cobbly coarse fragments in the profiles

because they are well drained and have loamy textures that usually tend to

increase water holding capacity. Flow rocks and lahars produce soils with higher

AWC due to higher levels of loamy textures and good drainage despite high

proportions of gravelly coarse fragments throughout the profile.

From a geomorphic perspective, colluvial and alluvial soils also have

important characteristics influencing plant growth. Soils developed in colluvial

deposits tend to have lower AWC resulting from sandy textures, excessive

drainage, and high levels of gravel and cobbles. These deposits generally lie on

steep slopes. Alluvial deposits, in contrast, also have sandy textures and excessive

drainage, but they are deep soils with low coarse fragment content and high

AWC. They lie on lower slopes, benches, and bottom locations.

North-South Relationships

Variables that describe most of the variation within the total data set also describe

most of the variation in each subregion (north, south, and east). Thus, most of the

factors influencing plant communities outlined above are important in each of

the subregions, and they influence vegetation in similar ways.

Samples in the southern portion of the range lie at significantly higher

elevations, indicating the gradual rise in elevation as latitude and longitude

decrease. Slopes in the samples were significantly steeper and bare ground was

higher in the south as well. Steepening of slopes became particularly noticeable

south of the Middle Fork of the Kings River near the boundary between the

Sierra and Sequoia National Forests. Understories in the north contained higher

levels of grass cover than samples from the south. However, other than climatic

and elevation differences, the major difference between northern and southern

samples was found in soil variation.
48 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Volcanic parent materials (lahars, andesitic and rhyolitic ash and mud flows,

and basalt deposits) and the soils derived from them occupied the northern

portion of the central and southern Sierra Nevada. They were seldom

encountered south of the Stanislaus National Forest. Parent materials in the

south were predominantly granitic. Samples in the north also occurred more

commonly on glacial deposits such as glacial till and outwash.

Taxonomically, soils in the south had a higher proportion of Entisols. These

were less developed soils. A significantly higher portion were Orthents and

Psamments. Orthents were typical of steeper, less stable slopes while the Psamments

were reflective of the sandy subsurface textures derived from higher portions of

granitic parent materials. Particle size classes in the north were more commonly

medial and medial-skeletal whereas those in the south were more often skeletal.

In the north, topsoils were better developed. Surface horizon thickness was

generally deeper in the north, which reflected the higher percentage of

Inceptisols. Samples from the south contained a higher percentage of Ochrepts—

Inceptisols with light colored, and presumably less developed, profiles. Soil

reactions were strongly acidic (pH less than 5.0) more often in the south due to

the presence of the volcanic flow rocks, lahars, and ash deposits in the north

which tended to have higher proportions of pH greater than 6.5. Soils in the

north tended to be darker in color. A higher proportion of subsurface colors were

dark gray to very dark brown in the north while they tended to be light gray and

yellow to dark yellow-brown in the south. This difference may be attributed to

higher rates of weathering in the north. Coarse fragment content was more

gravelly, cobbly, and stoney throughout the profile in the north due to the higher

percentages of volcanic soils encountered in northern samples. Soil textures were

finer and clay development appeared to be higher in these same soils; thus,

subsoil textures were more often loamy in the north and sandy in the south.

East-West Relationships

Samples from the Kern Plateau on the southern tip of the project area were

included as part of the eastside samples because conditions there were similar to

the eastside. Elevations of samples on eastside sites were substantially higher than

the westside, and slopes were steeper. Bare ground and surface gravel were

significantly higher, but shrub, forb, and grass cover were also higher. Conversely,

westside forests contained a greater moss component, and tree cover, litter cover,

and litter depths were higher compared to the drier conditions on the eastside.

Soils derived from pyroclastic deposits such as pumice and cinders were

located only on the eastside in the vicinity of Mammoth Mountain, which has

experienced such deposits in relatively recent times. Flow rocks, and ash deposits

were also sampled in higher proportions on the eastside while those derived

from granitic and metamorphic parent materials as well as the lahars were

sampled in higher proportions on the westside. Soils from eastside samples were

formed incolluvial and alluvial deposits in significantly higher proportions

because of the steeper slopes. Finally, glacial outwash deposits were encountered

more often on the eastside.

Soil taxonomy was similar to the north-south relationships. Inceptisols were

found in higher numbers on westside samples, and Entisols were found in

higher numbers on eastside samples, indicating the drier climatic conditions for

soil formation on the eastside that is comparable to the southern portion of the

study area. Of the soils classified as Entisols, Orthents and Psamments were

found in significantly higher proportions due to the steeper slopes and sandy

textures of eastside samples.

Soil reactions showed higher pH (greater than 6.5) in surface horizons on the

eastside. Although the relationship was not strong, this possibly reflects the

effect of lower precipitation with possible reduced leaching of cations. Soil pH
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 49

was probably not affected by differences in parent material nor the presence of

hardwoods (quaking aspen, for example) because significant differences were

not found in eastside versus westside samples when differentiated by these

variables. Eastside soil temperatures were substantially higher apparently in

response to more open sites and lower vegetative cover. Soils were darker in

color on the westside. Soil colors tended to range from dark brown to very dark

red brown on the westside and light gray to yellow on the eastside, suggesting

possibly higher levels of weathering on the westside.

Soil textures were sandy in both topsoil and subsoil on eastside samples.

Surface horizon coarse fragments were somewhat higher in content as compared

to westside sites. Subsurface horizons were also more gravelly as opposed to the

cobbly, stoney soils of the westside. Eastside samples were excessively drained,

and they had significantly lower AWC in general. These results are consistent

with the higher soil component derived from tephra deposits.

Ordination of Trees and Shrubs

DECORANA ordination was used for trees in each of the subregions (north,

south, and east) (fig. 14). The results showed that the relative position of species

from each subregion was similar even though the solution to each ordination

was unique. Although several variables were important in defining the position

of a species in each ordination, only three consistently explained the distribution

of tree species across all subregions as plotted on two axes.

On the first axis, species distributions were correlated with elevation and SRI.

As scores increased there was a general decrease in elevation and an increase in

SRI. Mountain hemlock, for example was a high elevation species that occurred on

sites with low SRI’s while, quaking aspen was a moderate to lower elevation

species occurring on sites with high SRI’s. On the second axis correlations were

considerably less well defined, and distributions were consistently explained

between subregions only by elevation and moisture stress. Elevation and moisture

stress increased with increasing scores in the northern and eastern ordinations

while they decreased with increasing scores on the southern ordination. Higher

order axes, such as axis 3 or 4, yielded no consistent pattern among variables. Thus,

the results showed that the observable patterns in tree species within these upper

montane forests that can be used to describe plant communities to a series level are

related in large measure to changes in elevation, SRI, and moisture stress.

To illustrate these relationships, plots comparing importance values3

 with

elevation and SRI are shown for several major tree species by subregion (fig. 15a).

Curves were smoothed with a locally weighted least squares algorithm to show

overall patterns. The shape of the curves among species in each of the subregions

was similar, and red fir was dominant in these forests between elevations of

about 7,000 and 9,000 feet on the westside and 7,700 to 9,500 feet on the eastside.

The upper elevations of red fir dominance were unclear from the samples in

the eastern portions of the range. Observation in the field indicate they were

similar to southern situations. Western white pine and lodgepole pine both

increased and white fir and Jeffrey pine decreased as elevation increased. Mountain

hemlock, while not plotted, showed patterns similar to western white pine. The

patterns of Jeffrey pine at lower elevations in the south were not as distinct as the

northern and eastside samples. Based on field observations, it was suspected this

may represent sampling distribution more than a real effect. SRI patterns were also

quite consistent, with red fir occupying mid-range values and other species

occupying more extreme positions (fig. 15b). The ability of white fir to maintain its

status among a wide range of SRI values was an interesting feature of this species.

Comparisons were also made using ordinations of shrub species (fig. 16). The

patterns were less defined with shrubs. In contrast to the ordination of tree

species, shrubs did not result in similar positions in the ordination space.

3 Importance values were calculated from relative cover and

relative frequency of tree species within a given elevation or

SRI band using the following

equation:

IV = Sum ((x/T) + (y/F)),

in which:

IV = Importance value of a

species in a sample.

x = Tree cover of the species

on a sample.

T = Total tree cover on a

sample.

y = Occurrence of a species in

a sample.

F = Sum of all species

occurring in a sample.
50 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Elevation (feet)

Importance Value

Red fir

East

Western white pine

Lodgepole pine

White fir

White fir

Jeffrey pine

Jeffrey pine

Lodgepole pineWestern white pine

Red fir

8060

100

90705040302010

0

6,000 7,000 8,000 9,000 10,000

Elevation (feet)

Importance Value

Red fir

North

Western white pine

Lodgepole pine

White fir

White fir

Mountain hemlock

Jeffrey pine

Jeffrey pine

Lodgepole pineWestern white pineMountain hemlock

Red fir

8060

140120100

4020

0

6,000 7,000 8,000 9,000 10,000

Elevation (feet)

Importance ValueRed fir

South

Western white pine

Lodgepole pine

White fir

White fir

Jeffrey pine

Jeffrey pine

Lodgepole pineWestern white pine

Red fir

8060

160140120100

4020

0

6,000 7,000 8,000 9,000 10,000

Figure 15a—Importance value by elevation and subregion for tree species in the central and southern Sierra Nevada.

Figure 14—DECORANA ordination by subregion for tree species in the central and southern Sierra Nevada.

First Axis Score

NORTH

LODGEPOLE PINE

WESTERN JUNIPER

JEFFREY PINE

WESTERN WHITE PINE

MOUNTAIN HEMLOCK RED FIR

WHITE FIR

QUAKING ASPEN SUGAR PINE

INCENSE CEDAR

Second Axis Score

0 100 200 300 400 500 600

600500400300200100

0

First Axis Score

SOUTH

LODGEPOLE PINE

JEFFREY PINE

WESTERN WHITE PINE

MOUNTAIN HEMLOCK

RED FIR

WHITE FIR

QUAKING ASPEN SUGAR PINE

INCENSE CEDAR

Second Axis Score

0 100 200 300 400 500 600 700

500400300200100

0

First Axis Score

EAST

LODGEPOLE PINE

WESTERN JUNIPER

JEFFREY PINE

WESTERN WHITE PINE

MOUNTAINHEMLOCK

RED FIR WHITE FIR

QUAKING ASPEN

Second Axis Score

0 100 200 300 400 500 600

600500400300200100

0
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 51 Figure 15b—Importance value by solar radiation index and subregion for tree species in the central and southern Sierra Nevada. Solar Radiation Index

Importance Value Red fir

North

Westernwhite pine Lodgepole pine

White fir

White fir

Jeffrey pine

Jeffrey pine

Lodgepole pineWestern white pine

Red fir

8060

140120100

4020

0

0.30 0.35 0.40 0.45 0.50 0.55 0.60

Solar Radiation Index

Importance Value

Red fir

South

Westernwhite pine

Lodgepole pine

White fir

White fir

Jeffrey pine

Jeffrey pine

Lodgepole pineWestern white pine

Red fir

8060

140120100

4020

0

0.30 0.35 0.40 0.45 0.50 0.55 0.60

Solar Radiation Index

Importance Value Red fir

East

Westernwhite pine

Lodgepolepine

White fir

White fir

Jeffrey pine

Jeffrey pine

Lodgepole pineWestern white pine

Red fir

9080706050

110

100

40302010

0

0.30 0.35 0.40 0.45 0.50 0.55 0.60

First Axis Score

NORTH

MOUNTAIN SNOWBERRY

SQUAW CURRANT

PINEMAT MANZANITA SAGEBRUSH

MOUNTAIN WHITETHORN SIERRA CHINQUAPIN

HUCKLEBERRY OAK

GREELEAF MANZANITA

Second Axis Score

0 100 200 300 400 500

500400300200100

0

First Axis Score

SOUTH

SQUAW CURRANT

PINEMAT MANZANITA

MOUNTAIN WHITETHORN

SIERRA CHINQUAPIN

HUCKLEBERRY OAK

GREELEAF MANZANITA

Second Axis Score

0 100 200 300 400 500

250200150100

50

0

First Axis Score

EAST

MOUNTAIN SNOWBERRY

SNOWBRUSH

SQUAW CURRANT

PINEMAT MANZANITA

SAGEBRUSH

MOUNTAINWHITETHORN

SIERRA CHINQUAPIN

HUCKLEBERRY OAK

GREELEAF MANZANITA

Second Axis Score

0 100 200 300 400

400300200

100

0

Figure 16—DECORANA ordination by subregion for selected shrub species in the central and southern Sierra Nevada.
52 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Furthermore, examination of gradients, as was done for tree species, was

performed for shrubs, and only moisture stress defined positions on the first axis

among all subregions. Moisture stress increased with increasing scores in the

northern ordination, while stress decreased with increasing scores in the southern

and eastern ordinations. No overall gradients emerged from second axis scores.

Thus, elevation increased on the second axis in the north; it decreased with

increasing scores on the eastside; and no pattern with elevation emerged in the

south. Similar to the analysis of tree species, shrub species were often

differentiated by several variables; however, none formed linear relationships

across all subregions.

Ordinations were also performed for each series. These were conducted to

define plant associations within a series. The results of these ordinations and

analysis within series are not presented here. They are included with the

description of each association. Generally, gradients expressed by linear

relationships within a single series were not strong, and a multivariate approach

often did little to adequately describe important relationships. Plant associations

within a series were often unique from others in the series, but these differences

were not expressed along the continuum of the ordination axis in an indirect

analysis. Direct gradient analysis using ANOVA and chi-square evaluations

often provided the understanding of differences between plant associations that

aided classification to plant association.

Using the Classification

This classification is designed for use in forested plant associations of the upper

montane where tree cover is generally greater than 10 percent. In some cases

individual sample sites contained less than 10 percent cover because they

represented the variation encountered within the association, and in one

association, Bolander’s locoweed, tree cover values in general were less than 10

percent due to the nature of the plant communities involved.

The classification includes a key for field identification of each plant

association, a description of each, and summary tables for cross referencing

features between plant associations (appendices E-H). The description of each

association includes comments on the distribution, environment, vegetative

composition and structure, soils, productivity, and management implications.

Species names are based on the flora described by Munz and Keck (1959). An

updated version of the taxonomy is now available in the Jepson Manual

(Hickman 1993), and name changes have occurred; however, the original

identification and analysis of the taxa were completed before the Jepson Manual

became available. Furthermore, before the classification was initiated, each

species was assigned a code for field data entry and analysis. These codes follow

Munz and Keck (1959), and they were not revised to incorporate the changes

resulting from the new flora at the time of preparation of the classification. In

those instances in which name changes have occurred in important upper

montane taxa, serious users should consult both references and be aware of the

changes. Some of the more obvious changes for the upper montane are a shift in

family for pyrola species (wintergreen), and a shift in genera for pyrola secunda,

sitanion (squirreltail), and stipa (needlegrass). Pyrola species are now placed in

the Ericaceae, and pyrola secunda is orthilia secunda in the Jepson Manual while

sitanion is placed in the genus Elymus, and the stipa are now listed in the genus

Achnatherum. Common names follow those of Abrams and Ferris (1975) and

McMinn (1939) in most cases.

Codes assigned to each species follow those in electronic data processing

codes for California wildland plants (Reed and others 1963). They were

supplemented by codes from the Plants of California—Alphabetical Listing (U.S.

Department of Agriculture, Soil Conservation Service 1994), for cases in which
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 53

the former reference did not contain codes. Each species code is a five-unit

alphanumeric combination of Latin names and numbers (appendix I). They consist

of the first two letters of the genus followed by the first two letters of the specific

epithet (species). A fifth letter code is used to distinguish between variety or

subspecies. A fifth number code is added if species duplications occur or to

indicate unidentified species of a genera. Thus, Sierra arnica, arnica nevadensis, is

coded as ARNE1 to distinguish it from pinemat manzanita, arctostaphylos

nevadensis, which is coded as ARNE2.

The title of each association is identified by four elements. First, a title

consisting of common names is presented for communication among users who

are familiar with the vegetation and setting. Second, a title consisting of the

complete Latin names of the indicator species is provided to allow cross

referencing and use in other studies. Third, a title consisting of the five-unit

species codes for the indicator species in the association is used; and fourth, a

regional code is used for correlation with other surveys and identification in

large data bases.

Association names are subdivided by life form first. This is followed by an

abiotic component if necessary. A slash (/) is used to represent a change in life

form, while a hyphen (-) is used to separate species in the same life form. For

example, ABMA-PIMO3/ARNE2 represents a plant association with indicator

species in two life forms (trees and shrubs) and two tree species (ABMA and

PIMO3) in the same life form. The order of species listing in the name is ranked by

cover, and it further identifies the vegetation series and subseries. The first name

indicates the species with highest cover and the series. The second and third name

identifies those species with the next lowest cover and the subseries. In forested

associations the tree layer identifies the series and subseries. The abiotic component

is separated by two slashes (//). Thus, TSME//STEEP represents a single species

association with an important topographic element of slope steepness.

Association descriptions attempt to highlight important differences or

features of each association that are not presented or readily apparent in the

tabular material. Extremes and statistically significant (p>0.05) relationships are

noted where applicable. The term “mean” is the arithmetic average of the values

sampled for a variable, while the term “mode” is the value or category that

occurs most frequently. Median values are those that occur halfway between the

range of observations. The species lists included with each description are not

comprehensive. Only species with greater than 20 percent constancy are listed.

Constancy is the percentage occurrence of a species in the samples used to

describe the association. For example, a constancy of 50 refers to the presence of

a plant in 50 percent of the samples. A complete listing of all species encountered

during sampling is included in appendix I.

Cover values are the average cover values, expressed as a percent of the

sample plot surface, where the species occurred. For example, a cover value of 20

means 20 percent of the sample plot was covered by that species. It does not

include areas within the stand that contained no cover of the species. This is

important when species are widely spaced in stands. To obtain a reasonable

estimate of the average cover of such species throughout a stand, one can

multiply the cover values by the constancy in decimal form. If a species occurred

on 50 percent of the samples and the cover value was reported as 10, the average

cover in a typical stand would be approximately 5 percent. The minimum value

recorded for species cover was 1 percent. For small forbs and grasses such values

are really indications of presence or absence, and they do not reflect the actual

cover of these species which, in many cases, are less than 1 percent.

Management implications are based on field observation of different

treatments throughout the range over several years, review of the literature, and

interpretation of data from the classification.
54 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

In the descriptions certain adverbs are used to indicate the degree of

occurrence of a particular feature and to avoid a graphical presentation or a

complete listing of distributions for all variables. The use of defined adverbs

attempts to portray modal situations or more closely describe the range of

conditions one can expect to see in the field. The terms used together with the

range of values expressed in percent are:

Occurrences

Less than 20 21-40 41-60 61-80 Greater than 80

Rare Occasional Usual Common General

Seldom Some Often Typical Characteristic

Few Uncommon Normal Most Predominant

Infrequent Ordinary Frequent Majority

Tend Many

Use of the Key

• A “stand,” as used in the classification, is considered to be a contiguous

group of plants sufficiently uniform in species composition, arrangement

of age and size classes, and condition to be a homogeneous and

distinguishable unit. No size is specified or implied in the use of the

word “stand” in the classification. A stand is defined by the user and

generally will be size-sufficient for use in management applications.

• Inclusions, or small areas with a different vegetative composition, may

lie within a stand. For purposes of classification, the user will have to

decide whether the area is small enough to represent the normal

variation in species within a stand or whether it is large enough to

merit recognition as a different plant association within a larger stand.

• Presence in the stand does not require a minimum percent of cover.

Occurrence is sufficient to establish presence.

• Time of year must be considered when identifying plants used as

indicator species. Plant identification early in the spring or late in the

fall is often difficult; however, familiarity with the plants and their

environment will often aid in the keying of a plant association during

these times. If a critical decision must be reached it is best to schedule

identification during early to midsummer for the associations described

in this classification.

• Canopy cover, as used in the classification, means the estimated vertical

projection on the ground of the area covered by those species used to

determine or describe the association.

• The convention used to key associations does not necessarily rely on

the most “common” or obvious species in the stand. It relies on those

species or life forms that distinguish the stand from others in the upper

montane forest. In some cases the difference may be obvious, but often

the plants will not be conspicuous. Thus, a PICO/LIGR1 association

will contain a large component of lodgepole pine and a somewhat

consistent but often inconspicuous component of Gray’s lovage.

• The key is self-referential in that sometimes a key step will lead to a

series or group of associations depending on overstory composition

and then lead back out of that group into another based on understory
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 55

composition. This is most noticeable in associations with large shrub

components, and it was done to allow stands with variation in

overstory composition but a similar understory to be keyed to the

appropriate association. For example, there were samples in which the

overstory was composed predominantly of red fir but with a

huckleberry oak understory. These cases occurred seldom enough that

insufficient samples were obtained to separately classify or describe

such an association. During analysis, these samples were classified

with the Jeffrey pine/huckleberry oak association. Descriptions of plant

associations include the resulting variation in stand composition.

• Suggested procedures that can be used to determine the associations

identified in the classification include:

- Walk the stand completely noting the species present and

approximate cover values by life form and crown position.

- Make an “initial approximation” of the series or association for the

stand. This approximation is designed to focus the classification on

the more likely associations that will be examined, to reinforce

decision points as they are reached, and to prevent major errors in

keying.

- Start at the beginning of the key for each stand and follow the steps

exactly to the final classification.

- Compare your classification with the description of the plant

association. Note constancy and cover values and compare them with

your observations of the stand.

- Return to the last decision point that seemed questionable if the

description does not correspond to your observations. Verify your

analysis at this point by taking the alternative choice in the Key.

Proceed with this choice to a new description, and again compare it

with the stand. Choose the description that best fits the stand.

- Remember that variation in vegetation across the landscape is

continuous, and many ecotonal areas will not fit neatly into any

particular association. Such areas should be classified with the most

similar association. In most cases, similar types have similar

characteristics and management properties.
56 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Key to Plant Associations

A. Red fir (Abies magnifica) present in the stand or adjacent stands . . . . . . . . . . . . B

AA. Red fir absent from stand or adjacent stands . . . . . . . . . . . . . . . . . Not Classified

B. Bolander’s locoweed (Astragalus Bolanderii) cover greater than 5 percent:

BOLANDER’S LOCOWEED ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . 59

BB. Bolander’s locoweed cover less than 5 percent. . . . . . . . . . . . . . . . . . . . . . . . . . C

C. Quaking aspen (Populus tremuloides) cover greater than 5 percent . . . . . . . . . . a

a. Western juniper (Juniperus occidentalis) and/or mountain mule ears (Wyethia

mollis) and/or sagebrush (Artemesia tridentata) and/or mountain pennyroyal

(Monardella odoratissima) and/or Jessica’s stickseed (Hackelia jessicae) and/or

Sierra wallflower (Erysimum perenne) and/or Brewer’s angelica (Angelica

Brewerii) present:

QUAKING ASPEN/MOUNTAIN PENNYROYAL ASSOCIATION . . . . . . 65

b. Not as above:

QUAKING ASPEN/CALIFORNIA CORN LILY ASSOCIATION . . . . . . . . 73

CC. Quaking aspen cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D

D. Western juniper (Juniperus occidentalis) cover greater than 5 percent . . . . . . . . a

a. Sagebrush and/or mountain mule ears cover greater than 5 percent:

WESTERN JUNIPER/SAGEBRUSH ASSOCIATION . . . . . . . . . . . . . . . . . . 81

b. Not as above:

WESTERN JUNIPER ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

DD. Western juniper cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E

E. Lodgepole pine (Pinus contorta) cover greater than 5 percent. . . . . . . . . . . . . . . a

a. Sagebrush and/or bitterbrush (Purshia tridentata) and/or mountain mule ears

cover greater than 5 percent:

LODGEPOLE PINE/SAGEBRUSH ASSOCIATION . . . . . . . . . . . . . . . . . . 201

b. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F

EE. Lodgepole pine cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F

F. Mountain mule ears cover greater than 5 percent:

RED FIR/MOUNTAIN MULE EARS ASSOCIATION . . . . . . . . . . . . . . . . . . 97

FF. Mountain mule ears cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . G

G. Tree cover greater than 10 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H

GG. Tree cover less than 10 percent:

(Talus, rock outcrops, shrub, forb, grass, meadow,

and riparian communities) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Not classified

H. Mountain hemlock (Tsuga mertensiana) cover greater than 5 percent . . . . . . . . a

a. Slope greater than 30 percent:

MOUNTAIN HEMLOCK//STEEP ASSOCIATION. . . . . . . . . . . . . . . . . . . 105

b. Slope less than 30 percent:

MOUNTAIN HEMLOCK ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . 113

HH. Mountain hemlock cover less than 5 percent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . I

I. Western white pine (Pinus monticola) cover greater than 5 percent . . . . . . . . . a

a. Pinemat manzanita (Arctostaphylos nevadensis) cover greater

than 5 percent:

RED FIR-WESTERN WHITE PINE/PINEMAT

MANZANITA ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

b. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c

c. Bush chinquapin (Castenopsis sempervirens) cover greater than 5 percent:

RED FIR-WESTERN WHITE PINE/SIERRA

CHINQUAPIN ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 57

d. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . e

e. Lodgepole pine cover greater than 5 percent:

RED FIR-WESTERN WHITE PINE-LODGEPOLE PINE ASSOCIATION. 137

f. Not as above:

RED FIR-WESTERN WHITE PINE ASSOCIATION. . . . . . . . . . . . . . . . . . 145

II. Western white pine cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . J

J. Sugar pine (Pinus lambertiana) and/or incense cedar (Calocedrus decurrens)

present:

WHITE FIR-SUGAR PINE-RED FIR ASSOCIATION . . . . . . . . . . . . . . . . . 153

JJ. Sugar pine and/or incense cedar absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . K

K. Jeffrey pine (Pinus Jeffreyii) cover greater than 5 percent . . . . . . . . . . . . . . . . . . . a

a. Huckleberry oak (Quercus vaccinifolia) cover greater than 5 percent:

JEFFREY PINE/HUCKLEBERRY OAK ASSOCIATION . . . . . . . . . . . . . . . 161

b. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c

c. Greenleaf manzanita (Arctostaphylos patula) and/or snowbrush

(Ceanothus velutinus) cover greater than 5 percent:

JEFFREY PINE/GREENLEAF MANZANITA-SNOWBRUSH

ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

d. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . e

e. Mountain white thorn (Ceanothus cordulatus) and/or Fresno ceanothus

(Ceanothus fresnensis), and or sagebrush and/or bitterbrush and/or sticky

leaved rabbit brush (Chrysothamnus viscidiflorus) cover greater than 5 percent:

JEFFREY PINE/MOUNTAIN WHITETHORN-SAGEBRUSH

ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

f. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . g

g. Pinemat manzanita cover greater than 5 percent:

RED FIR/PINEMAT MANZANITA ASSOCIATION . . . . . . . . . . . . . . . . . . 249

h. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

i. White fir (Abies concolor) cover greater than 5 percent:

RED FIR-WHITE FIR-JEFFREY PINE ASSOCIATION . . . . . . . . . . . . . . . . 185

j. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . aa

aa. Lodgepole pine cover greater than 5 percent. . . . . . . . . . . . . . . . . . . . . . L

bb. Not as above: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

JEFFREY PINE-RED FIR ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

KK. Jeffrey pine cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L

L. Lodgepole pine cover greater than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . a

a. Pinemat manzanita cover greater than 5 percent:

RED FIR-WESTERN WHITE PINE/PINEMAT MANZANITA

ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

b. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c

c. Sagebrush and/or bitterbrush and/or sticky leaved rabbit brush cover

greater than 5 percent:

LODGEPOLE PINE/SAGEBRUSH ASSOCIATION . . . . . . . . . . . . . . . . . . 201

d. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . e

e. Gray’s lovage (Ligusticum grayii) and/or Parish’s yampa (perideridia parishii)

and/or one sided wintergreen (Pyrola secunda) and/or arrowhead butterweed

(Senecio triangularis) and/or clover (Trifolium spp.) present:

LODGEPOLE PINE/GRAY’S LOVAGE ASSOCIATION . . . . . . . . . . . . . . 209
58 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

f. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . g

g. Stand basal area less than 225 square feet per acre, and/or total

tree cover less than 50 percent:

LODGEPOLE PINE//WOODLANDS ASSOCIATION . . . . . . . . . . . . . . . 217

h. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

i. Red fir cover greater than 5 percent:

RED FIR-LODGEPOLE PINE/WHITE FLOWERED

HAWKWEED ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

i. Not as above:

LODGEPOLE PINE ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

LL. Lodgepole pine cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M

M. White fir cover greater than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a

a. Huckleberry oak cover greater than 5 percent:

JEFFREY PINE/HUCKLEBERRY OAK ASSOCIATION . . . . . . . . . . . . . . . 161

b. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c

c. Greenleaf manzanita and/or snowbrush cover greater than 5 percent:

JEFFREY PINE/GREENLEAF MANZANITA-SNOWBRUSH ASSOCIATION 169

d. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . e

e. Mountain whitethorn and/or sagebrush and/or bitterbrush and/or sticky

leaved rabbit brush cover greater than 5 percent:

JEFFREY PINE/MOUNTAIN WHITETHORN-SAGEBRUSH

ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

f. Not as above:

RED FIR-WHITE FIR ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

MM. White fir cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N

N. Red fir cover greater than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a

a. Pinemat manzanita cover greater than 5 percent:

RED FIR/PINEMAT MANZANITA ASSOCIATION . . . . . . . . . . . . . . . . . . 249

b. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c

c. Huckleberry oak cover greater than 5 percent:

JEFFREY PINE/HUCKLEBERRY OAK ASSOCIATION . . . . . . . . . . . . . . . 161

d. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . e

e. Greenleaf manzanita and/or snowbrush cover greater than 5 percent:

JEFFREY PINE/GREENLEAF MANZANITA-SNOWBRUSH

ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

f. Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . g

g. Sagebrush and/or bitterbrush and/or sticky leaved rabbit brush

cover greater than 5 percent:

JEFFREY PINE/MOUNTAIN WHITETHORN-SAGEBRUSH

ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

h. Not as above:

RED FIR ASSOCIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

NN. Red fir cover less than 5 percent . . . . . . . . . . . . . . . . . . . . . . . . . . . Not classified
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 59

Association Descriptions

Bolander’s Locoweed Association

Astragalus bolanderii

ASBO

FBLFBL11

Sample size: 10

Distribution

The Bolander’s locoweed plant association occurs only on the westside in widely

separated locations between latitudes of 36°59' and 38°50'. It was sampled on the

Sierra, Stanislaus, and Eldorado National Forests. It is found at several locations

on the Sierra National Forest near Dinkey Creek and as far north as Wrights Lake

on the Eldorado National Forest. Although the dominant forb, Astragalus

bolanderii, occurs in small populations scattered throughout westside forests,

it becomes dominant only in the relatively small patches occupied by this

plant association. These communities are small in total area, but they form an

important component of the landscape diversity in upper montane forests.

Stands exceeding 10 acres have been observed; however, most stands are less

than 5 acres in size.

Environment

Elevations average nearly 8,000 feet; however, a high proportion of sites lie at

elevations above 8,000 feet on northeast and northwest aspects. They generally

occupy upper slope positions, and microrelief is characteristically uniform to

gently undulating. Slopes are usually less than 20 percent. Shallow slopes and

northerly aspects result in SRI levels that are moderate to low. Locoweed stands

have significantly more bare ground and surface gravel than most other sites,

while litter cover and litter depths are substantially less than surrounding
60 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

forested stands. The location of many sites on upper slopes results in stress

indexes that are moderate to high for the upper montane.

Variable Mean Range

Elevation (feet) 7,962 7,060-8,800

Slope (pct.) 19 8-31

Solar radiation index 0.475 0.399-0.574

Bare ground (pct.) 43 21-80

Surface gravel (pct.) 24 6-42

Surface rock (pct.) 3 0-15

Litter (pct.) 25 1-58

Litter depth (inches) 0.4 0.1-1.0

Stress index 0.51 0.42-0.57

Aspect: NE, NW.

Range: All.

Position: Upper slopes.

Range: Ridgetops, upper and middle slopes, benches.

Vegetation

Sites in this association are basically low forb dominated communities with

scattered trees. Adjacent stands are commonly dense forests. Total vegetative

cover is among the lowest of the forested communities of the upper montane. It

is significantly lower than most adjacent forest stands due to low tree cover and

the somewhat open growth habit of locoweed. This association has the lowest

tree cover of any in the upper montane, but sites carry high forb and grasscover

compared to other associations. Interestingly, species diversity is low given the

open conditions of this association. The total number of species is low compared

to most other sites, and stands tend to be dominated by a few species in the forb

layer which are relatively evenly distributed.

Red fir is the dominant tree species although trees are typically widely

scattered. A shrub layer is nonexistent. In addition to Bolander’s locoweed, the

forb layer is dominated by pussy paws and spurry eriogonum. These particular

forbs occur in these communities at higher cover levels than any other observed

in the upper montane. Sites have the appearance of open, dry environments, but

species such as pussy paws and Coville’s gayophytum are indicative of

moderately moist conditions, and soil conditions indicate relatively moderate

habitats.

Conifer regeneration is the lowest of all the associations in the forested

portions of the upper montane. No conifer species is regenerating well on these

sites. The average number of seedlings is less than 45 per acre, and regeneration

is absent over much of the area within a stand. The regeneration layer is

characterized by widely scattered red fir and lodgepole pine.

Average stand ages are relatively young compared to ages for other late seral

communities, and this would indicate these stands may be in transition to

occupation by conifers. Ages of the oldest trees on the sites were +321 years for

red fir and +176 years for lodgepole pine. These are comparable to ages achieved

by these same species in adjacent stands.

Examination of aerial photos from the 1940’s indicate these communities

have maintained their basic size, shape, and cover since that time. Ages of older

trees in adjacent forested stands would indicate there has been ample seed sources

and time for development of forested communities if such were possible. This has

not occurred, and future successional direction is difficult to predict at this time.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 61

Cover (percent) Mean Range

Total vegetative 64 25-90

Tree 4 0-15

Shrub 6 0-55

Forb 44 9-85

Grass 14 0-41

Moss 0.2 0-1

Stand age (years) 159 54-249

Diversity index

Simpson 0.39 0.14-0.87

Hill numbers

N0 8.9 3.0-16.0

N1 4.22 1.41-8.46

N2 3.58 1.16-7.22

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

ABMA Red fir 60 6 1-15

II. Understory trees

ABMA Red fir 20 1 1-1

PICO Lodgepole pine 20 1 1-1

III. Shrubs None

IV. Forbs

ASBO Bolander’s locoweed 100 29 2-80

CAUM2 Pussy paws 100 17 1-60

ERSP2 Spurry eriogonum 80 10 1-40

GAER Coville’s gayophytum 70 2 1-7

STTO Mountain streptanthus 50 3 1-7

MOOD Western pennyroyal 30 1 1-1

ERBR2 Brewer’s daisy 20 6 2-10

VIPU Mountain violet 20 1 1-1

V. Grasses and grass-like

SIHY Bottle brush squirreltail 40 2 1-5

STOC1 Western needlegrass 40 1 1-2

STCA1 California needlegrass 30 1 1-2

STCO1 Columbia needlegrass 30 14 1-4

Soils

Soils in this association are primarily Umbrepts in the Inceptisol order. Particle

size classes are varied and almost evenly divided between skeletal, sandy, loamy,

and medial. These size classes are indicative of the generally lower levels of rock

fragments in these profiles. One sample originated from metamorphic quartzite,
62 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

and a few samples in the north originated from lahar and tuff; however, soils

were typically formed in place from granitic parent materials.

These soils are deep. Generally, they are deeper than 35 inches, and often

they exceed 40 inches. Topsoil depths are varied, but they also tend to be quite

deep. Depths usually exceed 12 inches, and on average they are the deepest of all

plant associations in the upper montane. Conversely, coarse fragments are low

throughout the profile. Average coarse fragment contents in both the topsoil and

subsoil are the lowest of any in these high elevation forests, and coarse fragments

in both the topsoil and subsoil are characteristically less than 25 percent. Usually

both topsoil and subsoil are medium and moderately coarse textured sandy

loams with occasional sands and loams.

AWC ranges from moderately low to high in almost equal proportions, and

sites are not substantially different from other forested stands in the upper

montane. Commonly, these soils are well drained, and they often lie over bedrock

formations that are massive and unrootable. Erodibility is low to moderate on

most sites due to gentle slopes and moderately coarse soil textures. Soil

temperatures are significantly higher than most other sites. In spite of generally

lower solar radiation levels, the open conditions of this association apparently

allows average soil temperatures to reach the highest of any in the upper

montane. All stands had summertime soil temperatures which exceeded 54°

Fahrenheit. This is consistent with temperatures experienced by other open sites

in the study area.

Variable Mean Range

Depth of soil sample (inches) 38 30-40+

Topsoil

Depth (inches) 17 4-40+

Coarse frag. (pct.) 13 7-20

pH 5.4 4.8-6.2

Subsoil

Coarse frag. (pct.) 18 6-30

pH 5.8 5.1-6.6

AWC (inches) 3.7 2.1-6.5

Temp (20 inches) (Fahrenheit) 58 54-59

Productivity

These are essentially non-forested plant communities; consequently, potential

yields are low. Stand structures are irregular. Several tree size classes are usually

present; however, overall stand density is quite low, and smaller size classes are

under-represented (fig. 17). Pacific Southwest Region (Region 5) site index

averages 3, and site indexes are usually 3 or 4. The average stand density index is

the lowest of any forested association in the upper montane. Stand density

indexes are generally less than 165 in these stands, and values are only 15 percent

of those attained by denser stands such as the Red fir-white fir association. Basal

area stocking levels and cubic foot and board foot yields are also the lowest of

any of the forested associations.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 63

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

5

4

3

2

1

0

 Variable Mean Range

Region 5 site index 3 1-4

Forest survey site class 4 2-5

Stand density index 76 0-167

Quadratic mean diameter 21.8 0-46.0

Softwood volume (mcf/ac) 2.1 0-4.8

Softwood volume (mbf/ac) 14.7 0-33.3

Softwood basal area (sq ft/ac) 48 0-140

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Figure 17—Number of trees by

diameter class in the Bolander’s

locoweed plant association.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 87 - 9 - 4 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snags and down logs are not a common feature of this plant association since sites

are essentially open herbaceous communities. Some coarse woody debris falls into

the stand from adjacent vegetation types and occasionally from scattered trees

growing on the sites themselves, but contributions from these sources are rare.

Wildlife

Bolander’s locoweed communities are moderately foraged by large game. Several

species such as locoweed, squirreltail, western needlegrass, and columbia

needlegrass are used by large game as staple foods; however, except for locoweed

and columbia needlegrass, constancy and cover of most of these species are often

low. Deer use was commonly observed, but no pocket gopher activity was

observed on any of the sample sites.
64 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Range

These are transitional range sites that are used by livestock to access primary

range sites such as meadows and other moist habitats. Occasional cattle use was

observed. Bottle brush squirreltail and California needlegrass are primary forage

species, while western needlegrass, and columbia needlegrass are secondary

species in this association. All other species commonly occurring on these sites

are of low forage value.

Management Recommendations

Even though stands in this plant association are open, forb dominated

communities, they are not substantially different from other forested stands in

the upper montane, and they are commonly surrounded by dense forests. This

association has the environmental characteristics to produce denser stands of

trees and other vegetation, but this has not occurred. It is possible that factors

such as allelopathy, past fire severity, past grazing practices, or prehistoric use

patterns are influencing these sites, but such conclusions are speculative.

Attempts to convert these sites and change species composition to conifers or

other shrub, forb, or grass dominated communities should be treated with

caution. This association is best suited to providing general wildlife habitat,

plant species richness, and landscape level diversity in the upper montane.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 65

Quaking Aspen/Mountain Pennyroyal Association

Populus tremuloides/Monardella odoratissima

POTR/MOOD

HQAHQA12

Sample size: 19

Distribution

Quaking aspen is one of the most widely distributed trees in North America, and

it is present throughout the central and southern Sierra Nevada. Stands become

more extensive north and east in the range. The quaking aspen/mountain

pennyroyal plant association extends north generally from the John Muir and

Kaiser Wilderness on the Sierra National Forest near latitude 37°19’. Longitude

of the samples all lie west of 119°. It is best developed on the eastside of the Sierra

Nevada north of Bridgeport on the Toiyabe National Forest. Stands are never

very large or extensive except near Carson Pass and Hope Valley, and most

stands, particularly on the westside, are less than 5 acres in size.

Environment

This association is typically located on middle and lower slopes; a few stands are

found adjacent to wetlands and meadows, and some occur on benches and high

on slopes where subsurface water appears to be plentiful. In general, a

significantly higher proportion of sites lie on lower slope positions compared to

other forested plant associations. Slopes are gentle. Most sites occur on slopes

that are less than 25 percent. This association is not substantially different from

the quaking aspen/California corn lily association in general position on the

landscape; however, it does occur more often in upland settings. Environments

do not appear to be substantially different from other forested plant communities

in the upper montane; however, this plant association is often found on southeast

and southwest facing aspects where SRI levels are frequently moderately high to

high. Stress indexes range widely from low to high reflecting differences in AWC

and slope position of specific stands.
66 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,046 6,920-9,100

Slope (pct.) 18 3-33

Solar radiation index 0.503 0.442-0.560

Bare ground (pct.) 4 0-12

Surface gravel (pct.) 7 0-55

Surface rock (pct.) 3 0-25

Litter (pct.) 81 5-98

Litter depth (inches) 1.0 0.2-1.9

Stress index 0.44 0.33-0.55

Aspect: SE, SW, NW.

Range: All.

Position: Middle and lower slopes.

Range: Upper, middle, and lower slopes, toeslopes and benches.

Vegetation

Stands are mixed hardwood-conifer forests. In the north, stands are sometimes

interspersed within the red fir/mountain mule ears and western juniper/

sagebrush associations. Total vegetation cover is high resulting from

combinations of high tree, forb, and grass cover. Stands are characterized by the

presence of quaking aspen that may be present as either overstory or middle

layer trees. Red fir is common in the stands, although western juniper, a dry site

indicator, is usually a member of the tree canopy, particularly in eastside stands.

Other species are less well represented. Quaking aspen is indicative of moist

sites generally in upper montane forests; however, this association is not

significantly different in this regard than most other forested sites.

A shrub layer is characteristically present, and it occurs in higher amounts than

in many other associations. On most sites at least one of three species of snowberry

are present. Thus, either creeping snowberry, mountain snowberry, or Parish’s

snowberry are generally present on these sites. Creeping snowberry suggests mesic

conditions, although sagebrush, mountain snowberry, and Parish’s snowberry

suggest moderate to dry conditions. Forb and grass cover are substantially higher

than other forested associations. The species present also reflect the moderate to

dry conditions. Mountain pennyroyal, Coville’s gayophytum, and bottle brush

squirreltail indicate dry to moderate habitats although mountain mule ears,

mountain sweet cicely, and Fendler’s meadow rue reflect moderate to moist

conditions. Among the grasses, Bolander’s bluegrass indicates moist sites while

large mountain brome reflects moderate to dry conditions.

The total number of tree seedlings in these stands averages over 1,400 per

acre, and stands typically have more than 500 per acre. Overall, tree regeneration

is more common in the quaking aspen/mountain pennyroyal association than

on most other sites. This difference results from an abundance of aspen sprouts.

Tree regeneration is dominated by quaking aspen, but red fir is also common in

this layer. Western juniper is usually present, and lodgepole pine is sometimes

present as well. Both quaking aspen and western juniper are regenerating

significantly more often in this association than on most other sites.

Plant species diversity is high. It is among the highest in the forested

communities in the upper montane, and it is substantially higher than most other

forested stands except those in the western juniper series. This plant association

has many total species as well as a relatively large number of species with high

cover values. Abundant species are distributed among several life forms.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 67

The average age of stands in this association is significantly lower than most

others in the upper montane. Aspen trees are generally relatively young in the

Sierra Nevada; breast height ages of this species are commonly less than 90 years.

Aspen ages in these late seral stands ranged from 53 to 135 years for the oldest

trees. On the other hand, scattered predominants of conifer species, especially

western juniper, are considerably older. For example, the oldest tree measured

was a western juniper estimated at +710 years, and the ages of older trees were

usually greater than 200 years. The scattered nature of the older conifers in these

stands, and the relatively uniform sizes of the younger aspen middle layer would

appear to indicate that quaking aspen undergoes relatively constant turnover in

these stands. In general, the ages of the current aspen component in many stands

corresponds relatively well with the end of intensive grazing pressures in the

late 1800’s and the institution of fire suppression policies in the early 1900’s.

Stands appear to be following a successional sequence that would result in

dominance by conifers—usually red fir. Several samples, in fact, had a few

remnant aspen below an almost closed canopy of conifers, and usually many

aspen logs littered the forest floor in these cases. This condition appears to result

from both suppression of fire over the past several decades and grazing pressure

that keeps aspen sprouts severely hedged to the favor of conifers which are not

grazed as heavily. Before widespread fire suppression and the introduction of

grazing, aspen was favored on these sites due to available moisture and fire that

opened stands, encouraged aspen sprouting, and killed competing conifer

seedlings. Clearly, regeneration potential in the long-term lies with aspen in the

presence of fire and the absence of grazing. In the absence of fire and with

continued grazing pressure many of these stands will probably experience

reduction in the aspen component.

 Cover (percent) Mean Range

Total vegetative 94 70-100

Tree 71 33-85

Shrub 13 0-55

Forb 50 8-90

Grass 43 1-90

Moss 0.1 0-1

Stand age (years) 188 32-428

Diversity index:

Simpson 0.20 0.08-0.67

Hill numbers

N0 20.9 10.0-27.0

N1 8.86 2.44-14.57

N2 6.40 1.49-12.26

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

POTR Quaking aspen 100 48 16-81

ABMA Red fir 63 21 1-52

JUOC Western juniper 42 9 1-30

PICO Lodgepole pine 37 8 1-20

PIJE Jeffrey pine 32 2 1-2
68 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

II. Understory trees

POTR Quaking aspen 95 4 1-15

ABMA Red fir 63 2 1-20

JUOC Western juniper 42 1 1-1

PICO Lodgepole pine 32 1 1-1

ABCO White fir 26 1 1-2

III. Shrubs

SYAC Creeping snowberry 47 9 1-50

ARTR Sagebrush 32 4 1-10

RICE Squaw currant 26 1 1-2

ZRIMO Alpine prickly currant 21 22 1-55

RIRO Sierra gooseberry 21 2 1-3

SYVA Mountain snowberry 21 6 2-9

IV. Forbs

COTOW Wright’s blue eyed mary 58 14 1-60

DERII Mountain tansy mustard 58 2 1-30

MOOD Mountain pennyroyal 58 5 1-30

OSCH Mountain sweet cicely 58 6 1-70

THFE Fendler’s meadow rue 58 11 1-30

CIAN1 Anderson’s thistle 53 5 1-40

COLI2 Narrow leaved collomia 47 3 1-30

HAJE Jessica’s stickseed 47 4 1-15

GAER Coville’s gayophytum 42 4 1-50

SEAR California butterweed 42 1 1-2

ANBR2 Brewer’s angelica 37 1 1-2

ERPE3 Sierra wallflower 37 1 1-2

PODO3 Douglas’ knotweed 37 8 1-30

WYMO Mountain mule ears 37 5 1-13

ALCA2 Sierra onion 32 1 1-3

COTO1 Torrey’s blue eyed mary 32 10 1-40

CAAP Indian paint brush 26 1 1-2

LIGR1 Gray’s lovage 26 2 1-3

OSOC Western sweet cicely 26 1 1-3

PHHY Waterleaf phacelia 26 1 1-2

ALOB Red sierra onion 21 1 1-2

PESE3 Pine woods lousewort 21 1 1-1

VECA1 California corn lily 21 3 1-40

VIPU Mountain violet 21 6 1-20

V. Grasses and grass-like

POBO1 Bolander’s bluegrass 68 5 1-15

BRMA3 Large mountain brome 63 11 1-80

Characteristic Vegetation, continued

Percent cover

 Code Common name Constancy Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 69

ELGL Blue wildrye 47 26 3-80

SIHY Bottle brush squirreltail 47 9 1-40

STCA1 California needlegrass 42 7 1-20

CARO1 Ross’ sedge 32 2 1-10

STCO1 Columbia needlegrass 26 2 1-3

Soils

Soils are commonly Inceptisols. Most are Xerumbrepts and Cryumbrepts, but a

few Xerochrepts are also encountered. Alfisols and Mollisols are present in rare

cases; most often these are boralfs and borolls. Throughout the profile, particle

size classes are normally skeletal, but loamy size classes are not uncommon. Soils

are usually derived from either volcanic, granitic, or mixed parent materials.

Mixed lithologies are most commonly granitic-volcanic combinations

characteristic of parent materials found in the northern portion of the range

where this association occurs most often. These soils are usually formed in place

from bedrock, but many are also formed from material that has been moved. Soils

on nearly 50 percent of the samples were formed in alluvial and colluvial deposits

characteristic of locations on lower slopes. A few occurred in glacial deposits.

These soils are quite deep. Occasionally samples were less than 35 inches,

but most were greater than 40 inches deep. Textures in the topsoil are usually

loams with occasional sandy loams and sandy clay loams and a few sands.

Subsoil textures are varied, but they tend to be finer textured than the topsoils.

Thus, sands and sandy loams are encountered, but loams, sandy clay loams, clay

loams, and clays occur just as often, and a significantly higher proportion of the

soils in this plant association are medium and moderately fine textured compared

to adjacent forested communities. A significantly higher portion of the subsoils

are also 10 YR in hue with low chroma. These subsoils are essentially grayer in

color than most other sites.

AWC and stress indexes on these sites are not substantially different from

many other stands, but AWC is considerably less than those of the quaking

aspen/California corn lily association indicating drier conditions in this closely

related community. Topsoil pH values are significantly higher than most other

sites reflecting the presence of aspen and a tendency for hardwood litter to

decrease surface acidity. Soils usually lie over parent materials that are hard but

fractured and therefore rootable. These soils are essentially well-drained, and

erodibility is low to moderate due to finer soil textures and moderate slopes.

Variable Mean Range

Depth of soil sample (inches) 36 28-40+

Topsoil

Depth (inches) 12 4-38

Coarse frag. (pct.) 22 5-80

pH 6.4 5.7-7.1

Subsoil

Coarse frag. (pct.) 38 5-98

pH 6.0 5.4-7.6

AWC (inches) 3.4 0.5-5.1

Temp (20 inches) (Fahrenheit) 50 41-59

Characteristic Vegetation, continued

Percent cover

 Code Common name Constancy Mean Range
70 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Productivity

Site indexes show more variation than the quaking aspen/California corn lily

association, and they generally tend to be lower. Typical Pacific Southwest

Region (Region 5) site indexes are 3 and lower, and often they are less than 4.

Uncommon stands will have site indexes of 1 or 2. Stand densities are moderate,

and sites will usually have stand density indexes that exceed 400. Based on stand

density indexes, the average stocking is over 75 percent of fully stocked red firwhite fir stands, which is one of the densest upper montane associations. Most

stands had basal area stocking levels of less than 200 square feet per acre. Tree

height in this type is also significantly less as a result of the abundance of aspen

that seldom exceeds 80 feet. In conjunction with lower site indexes and the

smaller heights and diameter of aspen, these stands carry substantially less basal

area, cubic, and board foot volume than most other forested sites.

Stand structures are typically two-storied, with scattered large conifers over

a middle layer of aspen mixed with conifer saplings and young trees.

Substantially more trees less than 11 inches DBH occur than in most stands in the

upper montane, and size classes larger than 18 inches DBH are also less than

most other stands (fig. 18). This structure reflects the high number of aspen stems

present. Aspen in the Sierra Nevada does not typically exceed 24 inches DBH,

and the average diameter of aspen in these late seral stands was 15 inches.

Quadratic mean diameters for these stands are substantially lower than most

other forested sites in the upper montane. An equally important component of

the stocking in smaller size classes in this association is red fir which, as noted

earlier, appears to be successionally dominant. Larger trees in these stands are

often western juniper.

 Variable Mean Range

Region 5 site index 3 1-5

Forest survey site class 4 2-6

Stand density index 401 163-711

Quadratic mean diameter 12.2 1-23.2

Softwood volume (mcf/Ac) 6.4 1.9-10.6

Softwood volume (mbf/Ac) 26.6 0-77.0

Softwood basal area (sq ft/ac) 117 7-240

Hardwood volume (mcf/ac) 7.6 1.4-18.2

Hardwood basal area (sq ft/ac) 124 26-266

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

100

200

300

Figure 18—Number of trees by 400

diameter class in the quaking aspen/

mountain pennyroyal plant

association.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 71

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 26 4 7 2 - -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent 11 - - - 50 -

Coarse Woody Debris

Snag numbers are moderate. In general, mortality is concentrated in trees less

than 18 inches in diameter, reflecting the aspen component of these stands. Snag

numbers in large diameter classes are low. Most snags are shorter than 50 feet in

length, which also reflects the presence of aspen that tends to topple rather than

break off when dead. Snags tend to be sound. The majority occur in decay classes

between 1 and 3. Logs are short as well and evidence higher levels of decay.

Decay classes between 3 and 5 predominate.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 4.4 3.7 1.5 0 0.2 0.1 9.9

Snag height (feet)

<20 2.1 0.9 0.5 - - - 3.5

20-50 2.3 2.2 0.5 - 0.1 0.1 5.2

>50 - 0.6 0.5 - 0.1 - 1.2

Snag decay class

1 - 0.9 0.5 - - - 1.4

2 0.8 0.9 0.5 - 0.1 - 2.3

3 2.6 1.6 0.5 - - 0.1 4.8

4 0.8 0.3 - 0.1 - 1.2

5 0.2 - - - - - 0.2

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 8.7 5.0 1.0 0.3 15.0

Log length (feet)

<20 5.4 1.7 1.0 - 8.1

20-50 3.3 2.7 - 0.3 6.3

51-100 - 0.6 - - 0.6

>100 - - - - -

Log decay class

1 - -- - -

2 0.7 0.4 - - 1.1

3 5.4 3.0 - 0.3 8.7

4 2.3 1.3 0.3 - 3.9

5 0.3 0.3 0.7 - 1.3
72 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Wildlife

Wildlife forage appears to be moderate to high. Aspen is a preferred large game

forage species, and it is readily available from sprouts that are usually heavily

browsed. Mountain snowberry, mountain tansy mustard, Brewer’s angelica,

large mountain brome, and Bolander’s bluegrass are all staple foods in the large

game diet. They appear to be occurring often enough and in sufficient quantity to

be a component in the large game diet. Deer presence on these sites was moderate

to high, and pocket gopher presence was common.

Range

Stands sometimes occur adjacent to meadows and other moist areas where

livestock congregate in the summer season for shade, forage, and access to water.

Occasional stands are primary range sites, and use of range forage plants on

these sites can become heavy. Of the more common range species in these stands,

aspen appears to be a primary browse species. In most of the stands aspen

seedlings are heavily browsed by livestock, and this seriously reduces the ability

of aspen to regenerate. Only through continual resprouting can aspen escape

browsing enough times to permit it to eventually develop into tree form. Brewer’s

angelica and mountain sweet-cicely are secondary forb species. Large mountain

brome and California needlegrass are primary forage species, while bottle brush

squirreltail and blue wildrye are secondary species that occur with enough

frequency and high enough cover values to contribute to livestock forage.

Management Recommendations

Fire is an effective tool in the regeneration of these stands (Schier and others

1985). Examples from wildfires demonstrate abundant aspen regeneration after

stand replacing fires. Alternate prescriptions and results from efforts to convert

these stands to conifers is unknown at this time.

Except on the eastside, late seral stands in this plant association are often

small. Most are much less than 5 acres, and they are somewhat widely spaced

across the landscape. However, these stands appear to be important wildlife

habitat forage areas, and they are important elements in landscape diversity.

They may be among the oldest organisms in the Sierra Nevada. It would seem

appropriate at this time to maintain this association as a small but important

component of these forests. To accomplish this, however, will require

management emphasis to reduce grazing pressure and encourage aspen

establishment and growth most likely through the reintroduction of fire.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 73

Quaking Aspen/California Corn Lily Association

Populus tremuloides/Veratrum Californicum

POTR/VECA1

HQAHQA11

Sample size: 16

Distribution

The quaking aspen/California corn lily plant association is represented

throughout the Sierra Nevada. However, it is more common on the westside and

as one travels north through the range. More than 80 percent of the samples lay

north of 37°30’ latitude and west of 119° longitude or essentially from the Middle

Fork of the San Joaquin River north to the study area boundary. Stands are

widely spaced across the landscape generally in drainage bottoms. Best

development of the association occurs on the northern forests of the Stanislaus,

Eldorado, and Toiyabe. Except on the eastside, for example near Carson Pass,

stands are never very large or extensive, and most are less than 10 acres in size.

Environment

This is a lower elevation plant community. Sites are generally found at elevations

less than 8,000 feet, and the lowest stand sampled was at 6,500 feet on the Eldorado

National Forest. The lower elevations of this association result both from the

occurrence on northern forests in which upper montane plant associations in

general lie at lower elevations as well as its setting in lower slope positions on the

landscape. Aspects are varied and not significant in differentiating this type.

Slopes, however, are significantly less than other associations. The majority of sites

have slopes of less than 15 percent, and they are often less than 10 percent. Stands

characteristically lie on the lower one-third of slopes, on benches, and in toeslope

or bottom situations as part of a meadow or riparian complex. It differs from the

quaking aspen/mountain pennyroyal association that occurs more often in upland

settings. There is abundant moisture available to these sites. Their location on
74 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

lower slope positions probably results in high water tables. They have the lowest

stress index of any association in the upper montane.

 Variable Mean Range

Elevation (feet) 7,417 6,500-8,600

Slope (pct.) 12 2-31

Solar radiation index 0.486 0.378-0.536

Bare ground (pct.) 2 0-12

Surface gravel (pct.) 2 0-15

Surface rock (pct.) 3 0-10

Litter (pct.) 93 63-99

Litter depth (inches) 1.1 0.2-2.9

Stress index 0.40 0.31-0.54

Aspect: All.

Range: All.

Position: Lower slopes.

Range: Middle and lower slopes, toeslopes, benches.

Vegetation

Stands are generally mixed hardwood-conifer forests with high forb and grass

cover. Total vegetative cover is quite high; stands are usually quite dense. The

tree canopy is distinguished by relatively high levels of aspen cover particularly

in size classes between 6 and 18 inches in diameter. Aspen is mixed typically

with red fir and white fir which is indicative of lower elevations. Lodgepole pine

is an occasional component in the smaller size classes. Aspen is typically present

as a middle layer beneath a scattered upper layer of predominant conifers, but in

many cases late seral stands contain aspen as part of the upper tree canopy as

well. All of these species, but particularly quaking aspen, are indicative of

moderate to quite moist sites.

A shrub layer is generally not dominant in the association. Sierra gooseberry,

a moist site indicator is usually present as scattered shrubs, but the constancy

and cover of other shrubs is usually low. Understories of this plant association

are overwhelmingly defined by the presence of a relatively large number of

moist site indicators in the forb layer. Thus, mountain sweet-cicely, Fendler’s

meadow rue, Gray’s lovage, arrowhead butterweed, and California corn lily are

all indicators of the substantial moisture available on these sites. Although

California corn lily does not carry the high frequency sought in indicator species

for which an association is generally named, it is a constant, although sometimes

scattered, member of many stands, and it is used in the name to aid in

distinguishing the central concept of this association.

In general, there are significantly higher levels of tree regeneration in this

plant association than most others in the upper montane. The average number of

seedlings is over 1,800 per acre. Distributions in the samples are somewhat

skewed, but typically seedling counts will exceed 500 per acre. Regeneration is

dominated by quaking aspen, usually in the form of sprouts, which reflects

overstory species composition, but white and red fir are also present in relatively

high numbers. Both quaking aspen and white fir are significantly more abundant

as regeneration in this association compared to many others.

Plant species diversity is moderately high. It is significantly higher than most

other forested communities in the upper montane although it does not attain as

high a level as the species rich western juniper/sagebrush and quaking aspen/
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 75

mountain pennyroyal plant associations. Most stands have moderately high

numbers of total species and moderate levels of species with high cover values.

Quaking aspen and red fir tend to dominate, but cover is usually distributed

somewhat uniformly among species of all life forms.

These stands are significantly younger than most others. This results from

the younger ages of aspen in general in the Sierra Nevada, and from the presence

of younger age classes in the conifer component. Aspen ages in these late seral

stands ranged from 79 to 129 years for the oldest individuals, although the oldest

conifer measured was a Jeffrey pine at +526 years. Ages for the oldest

predominant red and white fir were +277 and +379 years, respectively. The

majority of the stems on these sites, particularly those in the smaller size classes,

however, are younger aspen. The scattered nature of the older conifers in this

type, and the relatively uniform size of the younger aspen in the middle layer

would appear to suggest that quaking aspen undergoes a relatively constant

turnover in these stands. The ages of the current aspen component appears to

correspond relatively well with the end of intensive grazing pressures in the late

1800’s and the institution of fire suppression policies in the early 1900’s.

Stands in the quaking aspen/California corn lily plant association appear to

be following a successional sequence that would result in dominance by

conifers—usually red fir. Evidence from this study indicate an increase in conifer

cover as stand age increases. This pattern appears to result from both suppression

of fire over the past several decades and grazing pressure that keeps aspen

sprouts severely hedged and favors conifers that are not grazed as heavily. Prior

to widespread fire suppression and the introduction of grazing, aspen was

favored on these sites due to the abundance of available moisture and fire that

opened stands, encouraged aspen sprouting, and killed competing conifer

seedlings. Clearly, regeneration potential in the long run lies with aspen in the

presence of fire and the absence of grazing. In the absence of fire and with

continued grazing pressures many of these stands will experience reductions in

the aspen component.

 Cover (percent) Mean Range

Total vegetative 94 82-99

Tree 78 49-96

Shrub 12 0-60

Forb 36 0-95

Grass 18 0-80

Moss 0.1 0-4

Stand age (years) 162 73-517

Diversity index

Simpson 0.29 0.09-0.67

Hill numbers

N0 15.3 7.0-26.0

N1 6.16 1.99-12.57

N2 4.48 1.49-10.48
76 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

POTR Quaking aspen 94 36 7-80

ABMA Red fir 81 28 7-82

ABCO White fir 69 18 1-51

PICO Lodgepole pine 38 16 2-73

II. Understory trees

POTR Quaking aspen 100 4 1-15

ABCO White fir 62 3 1-15

ABMA Red fir 56 2 1-7

PICO Lodgepole pine 31 1 1-2

III. Shrubs:

RIRO Sierra gooseberry 44 5 1-22

SYAC Creeping snowberry 31 15 1-55

IV. Forbs

OSCH Mountain sweet cicely 75 4 1-40

THFE Fendler’s meadow rue 56 2 1-5

SETR Arrowhead butterweed 50 4 1-20

VECA1 California corn lily 50 6 1-35

KEGA Kellogg’s bedstraw 38 1 1-2

LIGR1 Gray’s lovage 38 1 1-1

ACLA2 Common yarrow 31 5 2-10

BRLU2 Yellow brodiaea 25 1 1-2

ERPEA Wandering daisy 25 2 1-5

HIAL White flowered hawkweed 25 1 1-1

PESE3 Pine woods lousewort 25 2 1-3

PEPA5 Parish’s yampa 25 2 1-3

PTAQ Western bracken fern 25 17 2-60

VIPU Mountain violet 25 1 1-1

V. Grasses and grass-like

ELGL Blue wildrye 56 17 1-70

POBO1 Bolander’s bluegrass 56 1 1-3

CARO1 Ross’ sedge 44 3 1-10

BRMA3 Large mountain brome 31 6 1-20

Soils

Soils are typically Inceptisols. Rare sites contain Alfisols or Mollisols. The

Inceptisols characteristically lie in the Xerumbrept great group, and the Alfisols

and Mollisols are generally represented by Haploxeralfs and Haploxerolls.

Particle size classes are commonly loamy, indicative of the lower levels of rock

fragments in the profiles. These soils are usually derived from granitic parent

materials although sites occasionally develop from volcanic substrates, and a

few developed from mixed lithologies involving both granitic and volcanic

materials on the same site. These parent materials are those typically found in the
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 77

northern portion of the range where this association occurs most often. The

majority of these soils are formed in material that is transported from other areas

as alluvium and colluvium or glacial till and glacial outwash.

Soil depths can be considered deep. These soils commonly exceed 40 inches,

and only occasionally are they less than 35 inches. Textures in the topsoil are

most often loams with some sandy loams; a few sites contain clay loams. A

significantly higher proportion of the soils in this plant association have medium

and moderately fine textures in the surface horizons compared to adjacent

forested communities. Subsoil textures are similar. Usually, they are loams or

sandy loams with a few sandy clay loams and clay loams. Subsoils tend to carry

a higher proportion of sandy loams than topsoils. Coarse fragments in both the

topsoil and subsoil are low, and the average coarse fragment content throughout

the profile is among the lowest in the upper montane. Topsoils typically contain

less than 15 percent coarse fragments, and subsoils commonly contain less than

35 percent. Subsoil colors contain significantly higher proportions of 7.5 YR hues

than most other sites. Most of these have low value and high chroma. These soils

tend to be redder in hue, and they are usually darker and more strongly colored

as well.

These communities have the highest AWC of all associations in the upper

montane. It is substantially and significantly higher than most others in these

forest communities. This reflects the deep soils, finer soil textures, and low levels

of coarse fragments throughout the soil profile. Water holding capacities are

significantly higher than those in the quaking aspen/mountain pennyroyal

communities with which it is commonly associated. Soils are essentially welldrained, and erodibility is moderate due to the fine textures and shallow slopes.

They commonly overlie parent materials that are hard but fractured and rootable

and therefore able to provide additional sources of moisture to sites. Soil

temperatures are moderate for the upper montane; often they are less than 49°

Fahrenheit throughout the summer.

 Variable Mean Range

Depth of soil sample (inches) 37 27-40+

Topsoil

Depth (inches) 12 2-37

Coarse frag. (pct.) 15 1-55

pH 6.1 5.5-7.0

Subsoil

Coarse frag. (pct.) 27 7-55

pH 5.9 5.0-6.8

AWC (inches) 4.7 1.7-6.3

Temp (20 inches) (Fahrenheit) 50 42-57

Productivity

Pacific Southwest Region (Region 5) site indexes are characteristically better than

2, and many stands have site indexes better than 1. Stand densities are normally

greater than 400, and they are among the highest in the upper montane. Although

there is more variation in stand density in this association, they are comparable,

on average, to the densest stands in the study area. Based on stand density index

these stands are fully stocked. Tree height, as might be expected, is significantly

less than other major forested associations such as red fir and red fir-white fir.

Aspen tree heights ranged between 69 and 121 feet in this association compared

to the tallest conifer, a white fir, at nearly 180 feet. Thus, although densities may

be high, individual aspen trees do not carry as much volume as conifers, and
78 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

lower values are observed for measures of productivity. Basal area, cubic foot

volume, and board foot volume are significantly less than denser stands

elsewhere in these forests.

Stand structures are typically even-aged or two storied with scattered

predominant conifers over a layer of aspen mixed with conifer saplings and

young trees (fig. 19). In many stands aspen clearly dominates the middle layer

and few conifers occur. There are significantly higher numbers of trees smaller

than 18 inches in diameter compared to dense stands in the rest of the study area.

There are also significantly fewer stems larger than 24 inches DBH. This structure

reflects the high number of smaller aspen stems present and the fact quaking

aspen in the Sierra Nevada does not generally exceed 24 inches in diameter. The

average diameter of aspen in these late seral stands was approximately 16 inches.

Larger trees are usually red and white fir, and these are characteristically widely

distributed in stands. Quadratic mean diameters for these stands are substantially

lower than typical conifer associations in these late seral forests reflective of the

high aspen component.

 Variable Mean Range

Region 5 site index 1 0-3

Forest survey site class 2 1-4

Stand density index 519 119-1124

Quadratic mean diameter 14.5 6.6-24.0

Softwood volume (mcf/ac) 11.5 5.6-28.8

Softwood volume (mbf/ac) 43.7 7.1-125.3

Softwood basal area (sq ft/ac) 229 20-547

Hardwood volume (mcf/ac) 7.4 1.7-23.9

Hardwood basal area (sq ft/ac) 110 24-440

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

100

80

60

40

20

200

180

160

140

120

220

240

Figure 19—Number of trees by

diameter class in the quaking aspen/

California corn lily plant association.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 32 21 14 2 - -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - 31 -
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 79

Coarse Woody Debris

Snag numbers in this association are among the highest in the upper montane. In

particular, the number of snags less than 11 inches diameter is substantially

higher than most other stands. Most of the snags come from the smaller diameter

aspen. Snag heights are frequently taller than 50 feet reflecting the presence of

aspen that tends to topple rather than break off when dead. These snags tend to

be sound; the majority are decay classes 1 and 2. Log diameters are also smaller

in general, but lengths are variable. Commonly, they lie between 20 and 100 feet.

Logs are more decayed than snags, and typical decay classes in these logs is

distributed between 3 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 36.7 4.8 1.5 0.6 0.1 0.5 44.2

Snag height (feet)

<20 2.2 - 0.2 - 0.1 0.2 2.7

20-50 12.9 1.1 0.3 0.1 - 0.1 14.5

>50 21.6 3.7 1.0 0.5 - 0.2 27.0

Snag decay class

1 17.3 2.4 0.3 0.4 - 0.1 20.5

2 16.2 2.4 0.8 0.1 - 0.1 19.6

3 3.2 - 0.1 0.1 0.1 0.1 0.4

4 - - 0.1 - - 0.1 0.2

5 - - 0.2 - - 0.1 0.3

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 12.0 5.3 0.7 0.3 18.3

Log length (feet)

<20 4.0 1.6 - - 5.6

20-50 6.0 1.7 - - 7.7

51-100 2.0 2.0 0.4 0.3 4.7

>100 - - 0.3 - 0.3

Log decay class

1 1.0 - 0.4 - 1.4

2 2.7 0.3 - - 3.0

3 5.3 3.0 - - 8.3

4 2.7 2.0 0.3 0.3 5.3

5 0.3 - - - 0.3

Wildlife

Wildlife forage appears to be moderate to high since aspen is a preferred large

game food, and it is readily available from sprouts that are usually heavily

browsed. Common yarrow, western bracken fern, Bolander’s bluegrass, Ross’

sedge, and large mountain brome are all staple foods that occur with enough

frequency and cover to be important components of the large game diet. These

sites appear to also provide high values for hiding and thermal cover since they
80 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

are generally quite dense and often located near streams and meadows. Deer and

pocket gopher presence was common in this association.

Range

These stands often lie adjacent to meadows and other moist areas where

livestock congregates in the summer season for shade, forage, and access to

water. Many of these stands are primary range, and use of forage plants can

become heavy. Of the more common species, aspen appears to be a preferred

browse species. In many of these stands, aspen seedlings are browsed severely

by the end of the grazing season, and this seriously reduces the ability to

regenerate. Only through continual resprouting can aspen eventually escape

browsing enough times to permit it to develop into tree form. Mountain

sweet-cicely and California corn lily are secondary forage species in the forb

layer, and blue wildrye is a secondary grass forage species that occurs with

sufficient constancy and cover value to be important livestock forage.

Management Recommendations

The quaking aspen/Californian corn lily plant association is one of the wettest

habitats in the upper montane forests, and it is probably one of the more fragile.

These may be among the oldest organisms in the Sierra Nevada. Stands are

small; often they are less than 5 acres. They are somewhat widely spaced, subject

to replacement by conifers, and, at the present time, they are impacted by cattle

use. Species composition is somewhat varied. Often conifers make up a

substantial part of the stocking, and it appears this may be the result of

successional pressures on these sites as they develop into stands dominated by

conifers. Continued grazing seems to exacerbate this situation since the conifers

commonly associated with these stands are not preferred browse species. Thus,

grazing pressure favors conifer establishment and growth over aspen.

In a few instances, management has been applied in these stands. Timber

harvesting has been tried in a few scattered cases. This harvesting was primarily

a form of partial tree removal designed to remove part of the conifer component

and leave aspen. Smaller sub-merchantable conifers were also left on these sites.

In such stands aspen regeneration has not seemed to increase, partially due to

continued grazing pressure. Fire has been an effective tool in the regeneration of

these stands (Jones and DeByle 1985a). One site was observed in which the stand

was pushed over by mechanical means and the area broadcast burned. This was

very successful in establishing aspen, and several thousand aspen saplings per

acre now occupy this site. A few examples from wildfires also demonstrate

abundant aspen regeneration after stand replacing fires.

Because of the small size and widely separated nature of these stands, it

would seem reasonable at the present time to attempt to maintain the association

as an important component in the upper montane forest. The main contributions

of the quaking aspen/California corn lily association appear to be as wildlife

habitat, maintenance of plant species diversity, and contributing to landscape

level diversity. To maintain stands, however, will take management emphasis to

reduce grazing pressure and encourage aspen regeneration and growth, most

likely through the reintroduction of fire.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 81

Western Juniper/Sagebrush Association

Juniperus occidentalis/Artemesia tridentata

JUOC/ARTR

CJOCJO12

Sample size: 17

Distribution

The western juniper/sagebrush plant association occurs in the northeast portion

of the study area. It is best developed on the Toiyabe and Eldorado National

Forests near Carson Pass. It was sampled on the westside from Sonora Pass

north, and it has been observed south as far as the Kaiser Pass area. All samples

occurred north of 38° latitude, and longitudes were west of 119°30’. Stands can

cover extensive areas, but usually they are less than 25 acres due to normal

landscape patchiness.

Environment

This is a middle to high elevation plant association. Stands are generally found

between 7,500 and 8,500 feet elevation on southeast and southwest aspects.

These are higher elevations in the northern portion of the range where this

association commonly occurs. Slopes are commonly less than 30 percent. The

community is typically found on upper slopes and ridges, with occasional

occurrences on lower slope positions. Microrelief is commonly quite uniform.

The southerly aspects and slope positions result in considerably higher levels of

solar radiation compared to other sites in the study area. This association has

substantially more bare ground, surface gravel, and surface rock than most

others in the upper montane, and litter cover and depth are correspondingly less

than more mesic types. These are dry sites. Stress indexes are higher than most

other plant communities in these forests.
82 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,117 7,600-8,720

Slope (pct.) 26 8-42

Solar radiation index 0.533 0.470-0.580

Bare ground (pct.) 15 3-30

Surface gravel (pct.) 24 5-50

Surface rock (pct.) 13 0-62

Litter (pct.) 50 12-87

Litter depth (inches) 0.6 0.2-1.1

Stress index 0.54 0.44-0.64

Aspect: SE, SW.

Range: SE, SW, NW.

Position: Upper slopes.

Range: Ridgetops, upper, middle, and lower slopes.

Vegetation

Western juniper/sagebrush stands are open woodlands with a shrubby understory

of sagebrush. Total vegetative cover is high due to an abundant understory, and

although tree cover is low, sites have considerably higher levels of shrub, forb, and

grass cover. Patches of quaking aspen/mountain pennyroyal and the red fir/

mountain mule ears plant associations are often interspersed within this

association, indicating the variation of site conditions across the landscape. In

addition to sagebrush, individual sites may have high cover of mountain mule

ears which also indicates the association in these cases. Stands will sometimes

transition into and lie adjacent to the western juniper, quaking aspen/mountain

pennyroyal, and lodgepole pine/sagebrush plant associations, and on the eastside,

this association will transition into the sagebrush dominated shrublands of the

Great Basin which can cover large areas. Usually, however, stands are surrounded

by dense forested types as mesic site conditions are encountered. Western juniper

is the most abundant conifer in these communities, and it is the most dominant in

terms of tree cover. Jeffrey pine is a common associate, while red fir, western white

pine, and lodgepole pine are occasional components in the conifer overstory. Tree

distribution is often clumped and patchy.

Understories are a mixture of moderate to dry site indicators. Thus, the

understory is composed largely of sagebrush although other moderate to dry site

shrubs such as Parish’s snowberry, mountain whitethorn, mountain snowberry,

and bitter cherry are sometimes present as well. In the forb layer, Coville’s

gayophytum, and broad seeded rock cress are common indicators of dry sites,

and mountain pennyroyal is indicative of moderate to dry conditions. Mountain

mule-ears is indicative of mesic conditions, but few of the more common

moderate to moist site indicators are present. Bottle brush squirrel tail, large

mountain brome, Ross’ sedge, and Western needlegrass are the most common

grass species, and these are usually associated with moderate to dry conditions.

The presence of mountain mule ears in this association is reflective of the location

of many sites on the volcanic soils in the northern portion of the study area.

Conifer regeneration is extremely low in this association. Western juniper is

the most common species regenerating; occasional red fir and Jeffrey pine are

found, but the total number per acre of all species is typically less than 100, and

the median value is only 40 trees per acre. Conifer seedlings are often clumped in

patches around existing overstory trees rather than evenly distributed

throughout the stand. Western juniper and Jeffrey pine are regenerating

significantly more often on these sites.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 83

Plant species diversity is the highest of any plant community in the upper

montane. The association has the highest average total number of species. Low

tree cover in combination with a relatively uniform cover of several shrub, forb,

and grass species results in the distribution of abundant species among several

life forms.

The oldest trees in these stands typically exceed 250 years. Stands have high

proportions of older trees, and average stand ages are substantially older than

most other sites. This results from the relatively older ages that seem to be

attained by western juniper. The oldest tree sampled was a western juniper

estimated to be in excess of 2,000 years. The oldest Jeffrey pine was estimated at

+478 years, and the oldest red fir was +362 years.

Stand replacing disturbances are probably uncommon in this association.

Shrubby understories and southerly aspects favor larger, more intense fires.

Conversely, the noncontinuous nature of the understory, widely spaced trees, the

presence of large, somewhat fire resistant individuals, higher elevations, and the

natural patchiness of upper elevation landscapes all tend to preclude stand

replacing fires. The wide spacing of many of the existing individuals results in

uneven coverage and some level of survival by most species after fire. These

stands probably experience patchy burns that leave portions of the stand little

damaged while others are burned intensely. Isolated large and small trees

probably escape damage in most cases. Other disturbance elements such as

windthrow or avalanche are not common features of these stands. Insects, disease,

and lightning are more common, but they generally occur in localized situations

or on select species, and they do not generally result in stand replacement.

Reproductive strategies such as sprouting, widespread seed dispersal, or

delayed germination until seeds are scarified by fire is present in many of the

species on these sites. Sagebrush burns readily, but it is not a sprouter, and it does

not use fire to enhance seed germination. Often sagebrush does not reoccupy sites

for a considerable period after fire—perhaps as long as 50+ years. Future

occupancy of these sites by sagebrush is uncertain, and sites will probably change

into persistent forb and grass dominated communities in the understory. The

patchiness and wide spacing of many of the existing trees also results in uneven

coverage by disturbance elements, and many plants are left undamaged. In most

cases, future composition is largely determined by species currently on these sites.

Stand development appears to be sporadic as regeneration and growth

opportunities arise in response to disturbance. Disturbance creates opportunities

for regeneration, but many microhabitats are unsuitable for conifer reproduction,

and conifer establishment is a prolonged process on these sites. Disturbance also

provides opportunities of surviving individuals to increase growth. Isolated

patches of conifer vegetation escape many disturbances and proceed through a

period of crown closure and self-thinning. Isolated trees and small patches that

escape repeated disturbance eventually mature into larger members of the stand.

In time, an irregular structure develops reflecting numerous disturbances and

containing scattered large trees as residuals from several stand modifying events.

 Cover (percent) Mean Range

Total vegetative 74 35-99

Tree 31 4-75

Shrub 30 1-92

Forb 33 8-70

Grass 16 2-60

Moss 0.1 0-1

Stand age (years) 331 155-999
84 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Diversity index

Simpson 0.14 0.06-0.27

Hill numbers

N0 21.4 14.0-30.0

N1 11.08 6.40-20.19

N2 8.29 3.76-16.70

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

JUOC Western juniper 100 16 2-43

 PIJET Jeffrey pine 53 10 1-20

ABMA Red fir 41 8 2-23

PIMO3 Western white pine 29 5 1-10

PICO Lodgepole pine 24 16 1-45

II. Understory trees

JUOC Western juniper 59 1 1-4

ABMA Red fir 41 2 1-8

PIJE Jeffrey pine 35 1 1-1

PICO Lodgepole pine 24 1 1-1

III. Shrubs

ARTR Sagebrush 100 16 1-50

RICE Squaw currant 41 4 1-20

SYPA Parish’s snowberry 41 8 1-18

CECO2 Mountain whitethorn 35 8 1-25

PUTR Bitter brush 35 5 1-14

SYVA Mountain snowberry 35 1 1-2

PREM Bitter cherry 24 2 1-5

RIRO Sierra gooseberry 24 3 1-5

SYAC Creeping snowberry 24 6 1-22

IV. Forbs

MOOD Mountain pennyroyal 76 4 1-15

ERPE3 Sierra wallflower 71 1 1-1

GAER Coville’s gayophytum 71 6 1-30

CAAP Indian paint brush 65 2 1-5

WYMO Mountain mule ears 65 9 1-30

ARPL Broad seeded rock cress 53 2 1-10

COTOW Wright’s blue eyed mary 47 12 1-30

ERBR2 Brewer’s daisy 47 5 1-20

PESE3 Pine woods lousewort 47 1 1-1

SEAR California butterweed 41 1 1-3

 Cover (percent) Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 85

ERSP2 Spurry eriogonum 35 2 1-5

PODO3 Douglas’ knotweed 35 3 1-10

ALOB Red Sierra onion 24 4 1-6

CIAN1 Anderson’s thistle 24 10 1-20

COLI2 Narrow leaved collomia 24 1 1-3

CRY2 Cryptantha 24 4 1-10

ERNUD Naked stemmed eriogonum 24 1 1-2

KEGA Kellogg’s bedstraw 24 1 1-2

LUAN2 Anderson’s lupine 24 5 3-10

PHRA2 Branching phacelia 24 1 1-2

V. Grasses and grass-like

SIHY Bottle brush squirreltail 100 4 1-10

BRMA3 Large mountain brome 53 3 1-20

CARO1 Ross’ sedge 53 2 1-8

STOC1 Western needlegrass 53 2 1-3

MEBU Western oniongrass 41 1 1-2

POGR1 Pacific bluegrass 41 9 1-40

POBO1 Bolander’s bluegrass 29 3 1-10

STEL1 Elmer’s needlegrass 24 1 1-2

Soils

Soils are predominantly Inceptisols, and they typically belong to the Xerumbrept

great group. Occasional Cryumbrepts are also present. Particle size classes on

most sites are skeletal reflecting relatively high coarse fragment contents. Rare

samples are derived from metamorphic parent materials, and occasional samples

are derived from granite; however, the most common parent materials found are

the volcanic lahars, andesitic and rhyolitic flow rocks, and ash deposits common

in the northern portion of the range, and there is a significant relationship

between the presence of this plant association and soils derived from these

geologic substrates. Soils are typically formed in place from bedrock, but some

are formed in material which was deposited through glaciation or as alluvium.

Soil depths are variable, but basically they are shallow. Average depths are

among the shallowest of all plant associations in the upper montane Typical soils

were less than 35 inches deep, and often they were less than 25 inches. Topsoil

depths, on the other hand, are among the deepest in these upper elevation

forests. Topsoil textures are usually sandy loams and loams; whereas subsoil

textures are often cobbly or gravelly sandy loams with occasional loams. Coarse

fragments throughout the profile are significantly higher than most other

associations. Topsoils generally have greater than 15 percent coarse fragments,

and subsoils commonly exceed 35 percent. Subsoil colors contain significantly

higher portions of 5 Y hue or yellow soils in the Munsell color chart. They also

carry substantially higher numbers of soils which are 10 YR in hue but of low

value and chroma. Such soils tend to be very dark grayish brown.

The AWC in soils typical of this association are among the lowest in these

forests. Shallow soils, higher coarse fragment content throughout the profile, and

somewhat coarse textures result in the drier conditions experienced in these

stands. Soils on these sites typically occur over bedrock which is fractured and

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
86 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

rootable. Soil drainage is usually excessive, and erodibility is moderate to high

based on soil textures and slopes commonly experienced on these sites.

Summertime soil temperatures are substantially warmer than in most other

associations reflecting the southerly aspects and open conditions of many stands.

Most have temperatures which exceed 53° Fahrenheit.

 Variable Mean Range

Total soil depth (inches) 26 7-40+

Topsoil

Depth (inches) 12 4-28

Coarse frag. (pct.) 32 14-60

pH 6.0 5.2-6.5

Subsoil

Coarse frag. (pct.) 47 15-79

pH 6.0 5.4-6.7

AWC (inches) 2.3 0.4-5.7

Temp (20 inches) (Fahrenheit) 54 40-63

Productivity

Pacific Southwest Region (Region 5) sites indexes are moderate to low. Typical

indexes lie between 4 and 5. Stand densities are also low. Stand density indexes

are typically less than 300, and stocking levels based on average stand density

index are less than 45 percent of values attained in typical stands of the red firwhite fir association. Because of the presence of western juniper, which rarely

exceeds 65 feet in the Sierra, average tree heights are substantially lower than

most adjacent forested stands. The combination of lower site indexes, lower stand

densities, and shorter tree heights, result in basal areas and cubic and board foot

volumes which are considerably lower than well-stocked stands elsewhere in the

upper montane.

Stand structures are irregular. The most characteristic feature of these stands

are the low number of trees per acre, and the uniform distribution of trees in size

classes greater than 12 inches (fig. 20). Commonly, there are less than 100 trees per

acre, and the number of trees in all size classes are substantially less than most

other forested communities of the upper montane.

 Variable Mean Range

Region 5 site index 4 3-5

Forest survey site class 5 4-6

Stand density index 242 117-438

Quadratic mean diameter 21.8 11.0-39.5

Softwood volume (mcf/ac) 4.5 1.6-7.7

Softwood volume (mbf/ac) 29.9 10.7-84.1

Softwood basal area (sq ft/ac) 159 48-267

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 87

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 15 2 9 19 2 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent 54 - - - - -

Coarse Woody Debris

Snag numbers are among the lowest in the upper montane. They reflect the

open conditions of most stands. Snags are concentrated in the larger size classes.

Most are less than 50 feet tall, and they are distributed among several decay

classes. Logs were commonly less than 30 inches in diameter. All the samples in

this association were less than 50 feet in length, and most were less than 20 feet.

Logs showed more decay than snags. Log decay classes between 3 and 5 were

generally encountered.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0 0 0 0.1 0.3 0.4

Snag height (feet)

<20 - - - - - 0.1 0.1

20-50 - - - - 0.1 0.1 0.2

>50 - - - - - 0.1 0.1

Snag decay class

1 - - - - - 0.1 0.1

2 - - - - - --

3 - - - - 0.1 0.1 0.2

4 - - - - - 0.1 0.1

5 - - - - - --

Figure 20—Number of trees by

diameter class in the western juniper/

sagebrush plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

70

60

40

50

20

10

30
88 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 0.7 2.3 1.0 0 4.0

Log length (feet)

<20 0.7 1.6 0.3 - 2.6

20-50 - 0.7 0.7 - 1.4

51-100 -----

>100 - ----

Log decay class

1 -----

2 -----

3 - 1.0 0.7 - 1.7

4 0.4 0.7 0.3 - 1.4

5 0.3 0.6 - - 0.9

Wildlife

Western juniper/sagebrush stands are moderate to highly foraged by wildlife.

Bitter cherry and bitter brush are preferred species by large game, and sagebrush,

squaw currant, and sierra gooseberry are all staple foods in the shrub component.

All are present in at least moderate quantities. Indian paintbrush, Anderson’s

lupine, naked stemmed eriogonum, and branching phacelia are staples from the

forb layer, and bottle brush squirreltail, large mountain brome, Ross’s sedge,

Western needlegrass, Western onion grass, and Bolander’s bluegrass are

frequently occurring staples from the grass layer. Deer use was moderate, and

pocket gophers were often found on these sites.

Range

Range potential appears to be transitory as livestock move to primary range sites

such as meadows and other moist habitats. Cattle use is common on these sites.

These stands appear to be moderately productive for livestock. Bitter brush and

mountain snowberry are secondary forage species, and although few forbs in

this association are primary livestock forage, several of the grass species are

valuable as forage. Large mountain brome and bottle brush squirreltail are

primary grass species, and Western needlegrass and Pacific bluegrass are

secondary species. All occur with reasonable frequency and cover in this

association.

Management Recommendations

These sites have limited productive capacity and flexibility for stand management.

The open nature of the stands indicates that regeneration and establishment is a

lengthy and variable process under most conditions. Recommendations for

harvesting at the present time would be to treat stands with caution and expect

that results can be uncertain. Limited opportunities exist for salvage when it

occurs, but under the open conditions of most sites it would appear that woody

debris left in the form of snags and logs for wildlife or part of the nutrient pool

would be better direction for this association. Management emphasis should

provide for existing wildlife habitat, plant species richness, and the landscape level

diversity this association provides to the upper montane forests.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 89

Western Juniper Association

Juniperus occidentalis

JUOC

CJOCJO11

Sample size: 12

Distribution

The western juniper plant association is generally located at higher elevations in

the northern and eastern portions of the study area where it occurs in somewhat

widely separated patches across the landscape. Samples were located north of the

Kern Plateau near Monache mountain on the east and the Kings River on the west.

Longitudes were generally greater than 119°, reflecting locations in the north.

Individual stands tend to be small; most appear to be less than 10 acres in size.

Environment

Elevations typically lie between 7,500 and 8,500 feet. This association can be

considered a higher elevation community in the northern portions of the range

where it is commonly found. Occasional stands are found at elevations above

8,500 feet, but rarely do they occur below 7,500 feet. Sites are typically located on

southeast and southwest aspects where SRI levels are high, and they occur

generally on upper and middle slopes that are steeper than 20 percent. Site

microrelief is undulating to hummocky and broken. Surface features indicate

dry conditions with significantly more bare ground and surface rock than most

other associations. Surface rock is generally greater than 15 percent, and

individual stands sometimes have more than 50 percent rock covering the ground

surface. Stress indexes are the highest of any association in the upper montane.
90 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,133 7,560-8,960

Slope (pct.) 32 19-58

Solar radiation index 0.512 .361-.566

Bare ground (pct.) 6 1-20

Surface gravel (pct.) 13 2-65

Surface rock (pct.) 27 1-65

Litter (pct.) 58 6-96

Litter depth (inches) 0.9 0.3-2.9

Stress index 0.54 0.46-.60

Aspect: SE, SW.

Range: All.

Position: Upper slopes.

Range: Upper, middle, and lower slopes.

Vegetation

Stands are characteristically open, shrubby woodlands. Tree cover is

substantially lower than most other sites, and shrub, forb, and grass cover are

considerably higher than most other sites. Tree distribution is often clumped and

patchy. Overstories are dominated by western juniper, lodgepole pine, and

Jeffrey pine that are adapted to dry sites. Red fir, white fir, and western white

pine are occasional components in the overstory. These stands are often

surrounded by dense forested communities where conditions become more mesic.

Understories are dominated by species that favor dry habitats. In the shrub

layer pinemat manzanita and huckleberry oak are usually present. In addition,

moderate to dry site indicators such as mountain whitethorn, bittercherry, and

mountain snowberry are sometimes present as well. The forb layer contains dry

site species such as broad seeded rockcress and naked stemmed eriogonum as

well as dry to moderate indicators such as western pennyroyal and Coville’s

gayophytum. Finally, the grass component typically contains bottle brush

squirreltail and western needlegrass, both dry site indicators.

Conifer regeneration is extremely low. Except for the Jeffrey pine-red fir and

Jeffrey pine/mountain whitethorn-sagebrush associations, this plant association

has the lowest conifer regeneration of any of the forested communities in the

upper montane. Sites typically had less than 100 seedlings per acre, and seedlings

are often clumped in patches around existing overstory trees rather than evenly

distributed throughout the stand. Western juniper and lodgepole pine

regeneration are present significantly more often than in other associations,

whereas red fir is present significantly less often.

Plant species diversity is one of the highest in the upper montane forests.

Stands often have only a few less species on average than diverse communities

such as the quaking aspen/mountain pennyroyal and Western juniper/

sagebrush associations. Lower tree cover in combination with relatively uniform

cover of several shrub, forb, and grass species results in the distribution of

abundant species among several life forms.

The oldest trees in these stands are typically greater than 250 years although

average stand ages are comparable to others in these forests. Western juniper

attains greater ages than most other tree species in the upper montane, and the

oldest tree sampled in this association was a western juniper at about 630 years.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 91

This compares to ages for the oldest Jeffrey pine at +577 years and western white

pine at +506 years. The oldest lodgepole pine was estimated at +333 years.

Stand replacing disturbances are probably uncommon in these stands. Fire

patterns appear to be different from dense, forested associations. Shrubby sites

and southerly aspects favor larger, more intense fires. Conversely, large diameter,

widely spaced trees, and the noncontinuous distribution of the understory

provide uneven coverage and some level of survival by most species after fire.

Individual stand replacing fires may occur, but most stands probably experience

patchy burns with some portion of the stand completely consumed and others

left with little damage. Isolated large and small trees probably escape damage in

most cases. Other disturbance elements such as windthrow and avalanche are

not common features of these stands. Insects, disease, and lightning are more

common, but they generally occur in localized situations or on select species, and

they do not result in large scale stand replacement.

Reproductive strategies such as sprouting, widespread seed dispersal, or

delayed germination until seeds are scarified by fire is present in many of the

understory species on these sites. As examples, huckleberry oak is a rapid

sprouter after fire, and mountain whitethorn germinates profusely from seed

that has been scarified by fire. These species can rapidly reoccupy sites. Isolated,

undisturbed trees also provide a conifer component to the species occurring on a

site. In most cases, the species composition of future stands is largely determined

by species currently on these sites.

Stand development appears to be sporadic as opportunities arise in response

to disturbance. Disturbance creates opportunities for regeneration, but many

microhabitats are unsuitable for conifer regeneration, and conifer establishment

can be a prolonged process. Disturbance also provides opportunities for

surviving individuals to increase growth. Isolated patches of conifers that escape

repeated disturbance proceed through periods of crown closure and selfthinning. Isolated trees and small patches that escape disturbance eventually

mature into larger members of the stand. In time the stand develops an irregular

structure with several age classes reflecting numerous disturbances and

containing scattered large trees as the survivors of multiple disturbances.

 Cover (percent) Mean Range

Total vegetative 66 24-99

Tree 33 3-79

Shrub 31 3-65

Forb 24 1-80

Grass 13 1-80

Moss 0.7 0-2

Stand age (years) 288 129-625

Diversity index

Simpson 0.16 0.08-0.34

Hill numbers

N0 20.1 9.0-29.0

N1 9.63 4.27-14.78

N2 7.48 2.94-13.0
92 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

JUOC Western juniper 92 12 3-26

PICO Lodgepole pine 58 12 3-31

PIJE Jeffrey pine 50 9 3-22

II. Understory trees

JUOC Western juniper 67 1 1-1

PICO Lodgepole pine 58 1 1-1

PIJE Jeffrey pine 25 1 1-1

III. Shrubs

ARNE2 Pinemat manzanita 58 14 2-40

QUVA Huckleberry oak 50 21 1-60

CECO2 Mountain whitethorn 42 12 1-30

PREM Bitter cherry 42 2 1-5

RIRO Sierra gooseberry 42 2 1-6

SYPA Parish’s snowberry 33 1 1-2

SYVA Mountain snowberry 25 4 1-9

IV. Forbs

ERBR2 Brewer’s daisy 67 5 1-23

MOOD Mountain pennyroyal 67 3 1-10

ARPL Broad seeded rock cress 58 1 1-2

ERPE3 Sierra wallflower 58 1 1-1

ERNUD Naked stemmed eriogonum 50 1 1-3

SEAR California butterweed 50 2 1-4

GAER Coville’s gayophytum 42 2 1-3

CAAP Indian paint brush 33 1 1-2

COTOW Wright’s blue eyed mary 33 11 1-30

KEGA Kellogg’s bedstraw 33 1 1-3

ACLA2 Common yarrow 25 1 1-1

BRLU2 Yellow brodiaea 25 1 1-1

CHBR3 Brewer’s golden aster 25 4 1-10

CIAN1 Anderson’s thistle 25 2 1-3

CRY2 Cryptantha 25 1 1-1

LUAN2 Anderson’s lupine 25 6 1-15

PESE3 Pine woods lousewort 25 1 1-2

SIGL Glaucous sidalcea 25 3 2-4

STTO Mountain streptanthus 25 1 1-1

VIPU Mountain violet 25 1 1-1

WYMO Mountain mule-ears 25 1 1-1
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 93

VI. Grasses and grass-like

SIHY Bottle brush squirreltail 83 2 1-4

CARO1 Ross’ sedge 67 2 1-9

STOC1 Western needlegrass 58 2 1-3

PONE1 Hooker’s bluegrass 42 4 1-10

POGR1 Pacific bluegrass 33 10 1-30

POBO1 Bolander’s bluegrass 25 2 1-3

STCO1 Columbia needlegrass 25 3 1-6

Soils

The majority of soils in this association are Inceptisols. Most often they are

Umbrepts with occasional Ochrepts. Entisols classified as Psamments are

encountered on a few sites. Particle size classes in most stands are skeletal

reflecting relatively high coarse fragment content in the profile. A few samples

were derived from metamorphic and volcanic rocks, but soils were typically

formed from granitic parent materials. These soils are generally formed either

from alluvial deposits or weathered in place from bedrock.

Soils are moderately deep. They commonly exceed 25 inches in depth.

Occasionally they are deeper than 35 inches, but rarely are they deeper than 40

inches. Textures in both the topsoil and subsoil are generally sands or gravelly

sandy loams with rare occurrences of loams or clay loams. Coarse fragments in

the topsoil commonly range between 15 and 65 percent. They are significantly

higher than the western juniper/sagebrush association in the same series

although they are not substantially different from most other sites. Average

subsoil coarse fragments, on the other hand, are among the highest in the upper

montane. They often exceed 35 percent, and occasional stands contain more than

65 percent.

The average AWC of these soils is the lowest of any association in the upper

montane. Low values result from coarse textures and high coarse fragments.

High stress indexes reflect the combination of high SRI levels resulting from

southerly aspects and lower AWC. Soils commonly lie over parent materials that

are fractured and rootable. They are typically excessively drained, and erodibility

is moderate to high due to the coarse textures and moderately steep slopes of

most sites. Summertime soil temperatures are among the highest in the upper

montane. Temperatures characteristically lie above 53° Fahrenheit, and they

reflect the open stand conditions, steeper slopes, and higher SRI levels present.

 Variable Mean Range

Depth of soil sample (inches) 30 11-40+

Topsoil

Depth (inches) 11 3-16

Coarse frag. (pct.) 25 10-46

pH 6.0 5.2-7.1

Subsoil

Coarse frag. (pct.) 49 13-75

pH 6.0 5.2-7.1

AWC (inches) 2.1 0.5-3.8

Temp (20 inches) (Fahrenheit) 57 50-64

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
94 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Productivity

Productivity is low. Pacific Southwest Region (Region 5) site indexes are commonly

4 and lower, and only rare stands will have a site index greater than 3; these values

are significantly less than denser stands located on more mesic sites. Stand densities

are also low; stand density indexes are typically less than 300, and stocking levels

based on average stand densities are less than 45 percent of those attained in wellstocked stands elsewhere in the upper montane. Tree heights are substantially

shorter than in most other associations due to the presence of western juniper,

which is generally a shorter tree in the upper montane. In terms of basal area

stocking, cubic, and board foot volumes these stands carry considerably less

volume than most other forested associations due to poor site indexes, low

densities, and shorter heights. Average cubic foot volumes, for example are 28

percent of volumes in typical red fir-white fir stands.

Stand structures are irregular, but a characteristic feature of these stands is

the few trees per acre (fig. 21). Commonly, stands will contain less than 200 trees

per acre in all size classes. Trees smaller than 11 inches DBH are reasonably well

represented compared to sites with higher stocking levels; however, trees in size

classes greater than 12 inches are substantially less than in denser forested

associations.

 Variable Mean Range

Region 5 site index 4 2-5

Forest survey site class 5 3-6

Stand density index 225 44-464

Quadratic mean diameter 18.2 9.2-35.9

Softwood volume (mcf/ac) 4.2 1.7-8.8

Softwood volume (mbf/ac) 18.6 4.9-49.0

Softwood basal area (sq ft/ac) 129 40-320

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Figure 21—Number of trees by

diameter class in the western juniper

plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

70

60

80

90

40

50

20

10

30
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 95

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 8 19 20 23 - -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent 30 - - - - -

Coarse Woody Debris

Snag numbers are low reflecting the open stand conditions characteristic of the

association. Most snags sampled were larger than 25 inches DBH but less than 50

feet tall. Snags generally lie in decay classes 3 and 4. Downed logs are commonly

less than 30 inches in diameter and 50 feet long. Often they are less than 20 feet

long. Logs evidence higher levels of decay than snags. Most logs in these stands

lie in decay classes 4 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0 0.5 0.2 1.9 0.4 3.0

Snag height (feet)

<20 - - - 0.2 1.0 0.2 1.4

20-50 - - 0.5 - - 0.1 0.6

>50 - - - - 0.9 0.1 1.0

Snag decay class

1 - - - - - --

2 - - - - - 0.1 0.1

3 - - 0.5 0.2 1.0 0.1 1.8

4 - - - - 0.9 0.1 1.0

5 - - - - - 0.1 0.1

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 2.8 3.2 2.0 0.8 8.8

Log length (feet)

<20 2.0 2.4 - 0.4 4.8

20-50 0.8 0.4 2.0 0.4 3.6

51-100 - 0.4 - - 0.4

>100 - - - - -

Log decay class

1 - - -- -

2 - - -- -

3 - 0.8 - - 0.8

4 1.2 0.8 1.2 - 3.2

5 1.6 1.6 0.8 0.8 4.8
96 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Wildlife

These sites appear to be moderate to good for large game forage production.

Western juniper is a staple, and mountain whitethorn and bitter cherry are

preferred large game shrubs, and Indian paint brush, common yarrow, and

Anderson’s lupine are staple foods that occur frequently enough to supply a

consistent food source. Most of the grass species that are present in these sites are

staples in the large game diet, and Hooker’s bluegrass is a preferred grass

species. Sites in the western juniper plant association often showed signs of deer

and pocket gopher presence.

Range

Range potential appears to be transitory as livestock move to primary range sites

such as meadows and other moist habitats. Livestock use was common on these

sites. Bottle brush squirreltail and Hooker’s bluegrass are primary forage species.

Anderson’s lupine, western needlegrass, and Columbia needlegrass are all

secondary species. They occur with enough frequency and cover to be important

contributors to livestock forage.

Management Recommendations

These are dry habitats, and most stands should not be considered suitable for

timber production. Sites are harsh and not generally suitable for reforestation.

Rocky soils on sites with very low AWC and high moisture stress would indicate

low success rates with natural seeding or planting of nursery grown stock.

These stands have limited productive capacity and flexibility for stand

management. Poor regeneration and the open nature of these stands indicates

that conifer regeneration and establishment is a lengthy and variable process

under most conditions. Recommendations for harvesting at the present time

would be to treat stands in this type with caution and expect results to be

uncertain. Limited opportunities exist for salvage as it occurs, but on these open

sites it would appear that woody debris left in the form of snags and logs for

wildlife or part of the nutrient pool on the site would be better direction for these

stands. This is one of the most diverse plant associations in the upper montane

forests, and it provides an important contribution to landscape diversity.

Management emphasis should provide for existing wildlife habitat, plant species

richness, and the landscape level diversity this association provides to upper

montane forests.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 97

Red Fir/Mountain Mule Ears Association

Abies magnifica/Wyethia mollis

ABMA/WYMO

CFRFME11

Sample size: 14

Distribution

The red fir/mountain mule ears plant association occurs only in the northern

portion of the central and southern Sierra Nevada, and it is somewhat limited in

extent within that region. It was sampled on the Eldorado and Stanislaus National

Forests and the Lake Tahoe Basin Management Unit, and it has been observed on

the Toiyabe National Forest. It occurs primarily from the Pinecrest Peak area on

the Stanislaus north to an area east of Loon Lake on the Eldorado National

Forest. Latitudes in the samples were all north of 38° and longitudes were most

frequently west of 120°. Individual stands can cover large acreages such as those

near Mt. Reba in Alpine County, but most stands are less than 50 acres in size.

Environment

Stands commonly lay between 7,500 and 8,500 feet elevation. They

characteristically occupy southeast and southwest aspects on ridges and

upperslope positions where site microrelief is generally quite uniform. Slopes

are typically moderate; all samples were less than 35 percent. This plant

association has the highest solar radiation levels of any in the upper montane,

and it reflects the moderate slopes and southerly aspects typically encountered.

Mountain mule ears communities have significantly higher levels of bare ground

and surface gravel, and litter cover and litter depth are substantially less than

most other sites. Sites have high stress index resulting from high levels of solar

radiation and upper slope positions.
98 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 7,899 6,940-8,340

Slope (pct.) 22 5-38

Solar radiation index 0.534 0.498-0.570

Bare ground (pct.) 10 0-30

Surface gravel (pct.) 23 0-99

Surface rock (pct.) 4 0-14

Litter (pct.) 66 0-99

Litter depth (inches) 0.6 0.1-1.5

Stress index 0.53 0.38-.64

Aspect: SE, SW.

Range: SE, SW.

Position: Upper slopes.

Range: Ridgetops, upper and middle slopes, benches.

Vegetation

Stands are characteristically open, forested woodlands with an understory

dominated by mountain mule ears. Adjacent stands are composed of open

stands of western white pine, western juniper, and scattered lodgepole pine on

ridges alternating with dense forests elsewhere. Total vegetative cover on these

sites is high due to the high cover of mountain mule ears. Tree cover is

considerably less than most other sites, and tree distribution is often clumped

and patchy. Shrub cover is low, but forb and grass cover are substantially higher

than associated communities.

Red fir and Jeffrey pine are the dominant overstory tree species. Lodgepole

pine, western white pine, and western juniper are also encountered on some

sites. Except for an occasional creeping snowberry or mountain snowberry, the

shrub layer is essentially absent. Species composition in the forb and grass layers

are dominated by mountain mule ears, mountain pennyroyal, and bottlebrush

squirreltail. Mountain pennyroyal and squirreltail are often associated with dry

sites, and mountain mule ears, Bolander’s bluegrass, and blue wildrye are

indicative of moderately moist conditions.

Given the open character of these sites, it is interesting that species diversity

is only moderately high when compared to other plant associations in the upper

montane. The total number of species is often not high, and treecover is low due

to the relatively wide spacing of individual trees on most sites. The forb and

grass layers often have cover values which match or exceed those in the tree

layer. The number of abundant species is relatively high compared to other plant

associations, and the cover is somewhat uniformly distributed among the tree,

forb, and grass layer.

Conifer regeneration is among the lowest of all forested associations in the

upper montane. The average number of seedlings per acre is 160, but

distributions are skewed, and the median is only 50. Stands typically have less

than 100 seedlings per acre. Red fir is the only conifer species consistently

regenerating on these sites, and densities are usually very low.

The oldest trees in these stands are typically greater than 250 years. Ages of

the oldest trees encountered on these sites were +760 years for western juniper,

+726 years for western white pine, +369 years for red fir, and +311 years for

lodgepole pine. These ages are comparable to those for the same species in dense

forested stands adjacent to these sites.

A review of aerial photos from the 1940’s indicate these communities have
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 99

maintained their basic size, shape, and cover since that time. Ages of older trees

from adjacent forested stands can exceed 400 years; thus, seed sources probably

have been in place and sufficient time would appear to have passed for forested

communities to develop if such were the successional direction these stands were

headed. The root system of mountain mule ears contains a substantial taproot,

almost tuberous in character, and the ability of this species to persist is evident.

Early grazing or Native American burning may have created or maintained these

communities, but work has not been done in support of these ideas, and there are

arguments against such a hypothesis; consequently, the future successional

direction of these communities is difficult to predict at this time.

 Cover (percent) Mean Range

Total vegetative 79 52-99

Tree 25 0-89

Shrub 5 0-45

Forb 54 6-98

Grass 19 1-98

Moss 0 0

Stand age (years) 190 36-344

Diversity index

Simpson 0.28 0.10-0.72

Hill numbers

 N0 13.8 4.0-20.0

 N1 6.11 1.68-11.81

 N2 4.66 1.38-9.80

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

ABMA Red fir 50 24 5-48

PIJE Jeffrey pine 43 17 1-37

PIMO3 Western white pine 29 6 2-12

II. Understory trees

ABMA Red fir 57 2 1-2

ABCO White fir 21 2 1-2

PIJE Jeffrey pine 21 1 1-1

PIMO3 Western white pine 21 1 1-1

III. Shrubs

SYAC Creeping snowberry 29 4 1-10

IV. Forbs

WYMO Mountain mule ears 100 36 25-98

MOOD Mountain pennyroyal 79 8 1-25

COTOW Wright’s blue eyed mary 43 13 1-60

ERPE3 Sierra wallflower 43 1 1-1

GAER Coville’s gayophytum 36 2 1-5

LUAN2 Anderson’s lupine 36 1 1-2
100 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

IV. SIGL Glaucous sidalcea 36 12 1-30

ALCA2 Sierra onion 29 1 1-1

BRLU2 Yellow brodiaea 29 2 1-5

CAAP Wavy leaved Indian paint brush 29 3 1-10

CHBR3 Brewer’s golden aster 29 2 1-5

CRY2 Cryptantha 29 1 1-1

PHHY Waterleaf phacelia 29 3 1-10

ARPL Broad seeded rock cress 21 6 1-15

CAUM2 Pussy paws 21 1 1-1

V. Grasses and grass-like

SIHY Bottle brush squirreltail 79 3 1-10

BRMA3 Large mountain brome 29 1 1-2

ELGL Blue wildrye 29 9 1-30

POBO1 Bolander’s bluegrass 29 3 1-10

STCA1 California needlegrass 29 4 1-8

Soils

Soils are characteristically Inceptisols which occur as Xerumbrepts and

Cryumbrepts. Rare sites contain Alfisols. One sample originated from granitic

parent material, and one originated from mixed lithologies; however, parent

materials are predominantly the volcanic lahars of the Mehrten formation which

are common in the northern portion of the range. Soil from the mixed lithology

profile was a combination of volcanic and granitic parent materials that were

mixed through glaciation. There is a significant correlation between the

occurrence of this plant association and soils derived from volcanic parent

materials. Typically, these soils are formed in place from bedrock, and rarely are

they formed from deposited materials such as glacial till and colluvium.

These soils are often deep. Commonly, they exceed 35 inches although

occasional sites can be less than 25 inches. Topsoil coarse fragments tend to be

low; usually they are less than 15 percent. Subsoil coarse fragments, on the other

hand, are high, and they often exceed 35 percent. Topsoil textures are usually

sandy loams with occasional loams and sands. Subsoil horizons are finer textured

and usually contain loams, sandy clay loams, and clay loams. Occasional sites

contain sands and sandy loams.

The AWC of these soils is variable, but it clusters at two extremes: sites with

high to moderately high water holding capacity, and those with low water

holding capacity. There appears to be no landscape pattern to these differences.

They reflect differences in soil depth, soil texture, and coarse fragment content

that represent the normal variation within these plant communities. Soils lie over

bedrock formations which are both fractured and rootable and unfractured and

unrootable in equal portions. Similarly, the soils in this plant association are

either well or excessively drained, and they are usually moderately erodible. Soil

temperatures are substantially higher than most other sites reflective of the open

stand conditions and southerly aspects. Summertime soil temperatures are

typically higher than 49° Fahrenheit.

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 101

Variable Mean Range

Depth of soil sample (inches) 34 15-40+

Topsoil

Depth (inches) 11 3-22

Coarse frag. (pct.) 19 3-46

pH 5.9 5.5-6.7

Subsoil

Coarse frag. (pct.) 40 6-92

pH 5.8 5.3-6.7

AWC (inches) 3.2 0.8-5.9

Temp (20 inches) (Fahrenheit) 54 46-67

Productivity

Although Pacific Southwest Region (Region 5) site indexes are widely distributed,

they rate as 3 and lower in most stands. Stand densities are also low. Stand

density indexes are commonly less than 200, and stands will typically contain

less than 50 trees per acre. Stocking levels average around 30 percent of those

attained in the red fir-white fir plant association which is one of the densest of

upper montane forested communities. Stocking in these late seral stands also

resides in the larger individuals of the stand. Average quadratic mean diameters

approach those of typical red fir stands which carry much of their stocking in

larger size trees. Tree heights reflect the moderate to lower site indexes

experienced on these sites. The tallest red fir measured 164 feet, but the tallest

lodgepole measured only 87 feet, the tallest western white pine 70 feet, and the

tallest western juniper 48 feet. Moderate to low site indexes coupled with lower

stocking levels result in low basal area stocking and cubic and board foot

volumes.

Stand structures are irregular, and smaller size classes are poorly represented.

In general, stands are open, and there is a rather uniform distribution of trees in

all size classes reflecting a lack of trees in size classes below 25 inches (fig. 22).

 Variable Mean Range

Region 5 site index 3 1-5

Forest survey site class 4 2-6

Stand density index 171 50-401

Quadratic mean diameter 23.6 8.6-32.0

Softwood volume (mcf/Ac) 5.4 1-16.6

Softwood volume (mbf/Ac) 33.6 4.0-111.6

Softwood basal area (sq ft/ac) 122 32-344

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
102 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 66 7 4 13 7 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent 3 - - - - -

Coarse Woody Debris

Snag numbers are among the lowest in the upper montane. They reflect the

open nature of these stands and the concentration of trees in larger size

classes. Snags less than 30 inches DBH are few and widely scattered. Mortality

in the larger size classes appears to be related to senescence and is randomly

distributed among all species. Snag heights are variable, but typically they

are shorter than 50 feet indicating a tendency for standing snags to break off

over time. The majority of snags are decay class 3 and lower. Log diameters

are also variable, but lengths are frequently less than 20 feet. They exhibit

higher levels of decay than the snags. All logs sampled in these stands were

decay classes 4 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0 0 0 0.1 0.5 0.6

Snag height (feet)

<20 - - - - 0.1 - 0.1

20-50 - - - - - 0.3 0.3

>50 - - - - - 0.2 0.2

Snag decay class

1 - - - - - 0.2 0.2

2 - - - - - --

3 - - - - 0.1 0.3 0.4

4 - - - - - --

5 - - - - - --

Figure 22—Number of trees by

diameter class in the red fir/mountain

mule ears plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

9

8

7

6

5

4

3

2

1

11

12
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 103

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 0.3 0.9 0.3 0.6 2.1

Log length (feet)

<20 0.3 0.9 0.3 - 1.5

20-50 - - - 0.6 0.6

51-100 -----

>100 - ----

Log decay class

1 -----

2 -----

3 -----

4 0.3 0.6 - 0.3 1.2

5 - 0.3 0.3 0.3 0.9

Wildlife

Large game forage possibilities appear moderate. Of the more abundant and

commonly occurring forage, Indian paint brush, waterleaf phacelia, bottle

brush squirreltail, and Bolander’s bluegrass are considered staple foods for

large game; however, except for bottle brush squirreltail, most of these species

are of relatively low constancy and cover. In general, deer use and pocket

gopher activity on these sites were observed to be low.

Range

Range potential appears to be transitory as livestock move between primary

forage sites such as meadows and other moist habitats. Cattle presence was often

observed, but sites in this association do not appear to be highly used. Bottle

brush squirreltail, large mountain brome, and California needlegrass are primary

forage species for livestock.

Management Recommendations

Red fir/mountain mule ears sites have many environmental characteristics that

are similar to more heavily forested communities in the upper montane, but they

do not have higher levels of tree cover. Soil properties are similar to many stands

with dense forest cover, and other features of the environmental setting are

similar to stands with much higher levels of tree cover. These sites do share

higher solar radiation levels and warmer soil temperatures with other opencanopied plant communities such as those in the western juniper and Jeffrey pine

series. Additional factors such as competition during seedling establishment,

allelopathy, past fire severity, past grazing practices, or prehistoric use patterns

may influence these sites, but such conclusions are speculative at this time.

Limited opportunities exist for salvage when it occurs, but on these open

sites, retaining woody debris in the form of snags and logs for wildlife or part of

the nutrient supply would be better management for this association. Attempts

to change species composition to conifer or other shrub, forb, or grass dominated

communities should be treated with caution. Management emphasis should

provide for existing wildlife habitat, plant species richness, and the landscape

level diversity this association contributes to upper montane forests.

USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 105

Mountain Hemlock//Steep Association

Tsuga mertensiana//steep

TSME//STEEP

CHMCHM11

Sample size: 17

Distribution

The mountain hemlock//steep plant association is located in the northwestern

and northeastern portions of the study area. In general, mountain hemlock does

not extend south of latitude 37° in the Sierra Nevada although isolated small

stands are reported as far south as latitude 36°37’. The most southerly stand in

this association was sampled west of Margaret Lake on the Sierra National

Forest. Latitude at this point is slightly greater than 37°. Most samples occurred

north of Latitude 37°30’, and west of longitude 119°. Some were located on the

Inyo and Toiyabe National Forests and the Lake Tahoe Basin Management Unit.

Stands are usually smaller than 10 acres in size, and in many cases they cover but

a small portion of an acre.

Environment

This association occurs over a wide range of elevations in the upper montane

although stands characteristically lie above 7,500 feet. Stands often signal the

transition into subalpine forests above. Some stands lie above 8,500 feet especially

in the south and on the eastside. Aspects are predominantly northeast to

northwest, and slopes exceed 30 percent. Microrelief is frequently broken and

hummocky. SRI values on these steep north facing slopes are the lowest of any in

the upper montane, and winter snow packs often linger for a considerable period

into the summer season as one effect of these lower solar radiation levels. Stands

typically lie on upper slopes. Most often they are found just below ridge tops on

very steep north facing aspects. Stress indexes in this association are low due to

lower solar radiation levels resulting from north aspects and steep slopes.
106 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,241 7,120-9,360

Slope (pct.) 45 30-60

Solar radiation index 0.355 0.273-0.478

Bare ground (pct.) 1 0-3

Surface gravel (pct.) 5 1-20

Surface rock (pct.) 13 0-49

Litter (pct.) 82 45-99

Litter depth (inches) 1.8 0.2-8.0

Stress index 0.49 0.37-0.57

Aspect: NE, NW.

Range: NE, NW.

Position: Upper slopes.

Range: Upper, middle, lower slopes, bottoms.

Vegetation

Stands are dense forests with open understories. The overstory is dominated by

mountain hemlock, but western white pine and red fir are also important

components in the overstory layer. Lodgepole pine is a rare member of this

association. Stands are often found associated with the red fir-western white

pine and red fir associations on mesic sites at high elevations.

Understories are sparse, and a shrub layer is essentially nonexistent. In the

forb layer a range of species from mesic to dry site indicators are typical; however,

none are abundant. Thus, both a mesic site indicator such as white-flowered

hawkweed, and a dry site indicator such as broad-seeded rockcress can be present

in the same stand. The grasses suggest a similar character with the presence of a

mesic to dry indicator such as Ross’ sedge, and a moist site indicator such as

Bolander’s bluegrass sometimes occurring in the same stand. More often,

however, these species indicate differences between sites. Moss is present in these

stands significantly more often compared to many other associations.

Conifer regeneration is moderate. Often more than 500 seedlings per acre are

present, and the average is almost 800. Although regeneration is predominantly

red fir, both mountain hemlock and western white pine are regenerating with

significantly higher frequency than in other upper montane stands.

Plant species diversity is moderate to low. This association has few species in

general, and sites are dominated by relatively few tree species that outweigh the

cover values of the shrub, forb, and grass layers. Abundant species are few in

number, and they are concentrated in the tree layer.

The oldest trees in these stands are typically greater than 250 years. Average

stand ages are significantly older than most other stands in the upper montane

although the age of the oldest trees are comparable to those found in other

associations. The oldest mountain hemlock in the sample was +394 years, and the

oldest red fir was estimated at +449 years.

Large scale, stand replacing disturbances are probably uncommon in this

association. Although they may occur, field observation and examination of

stand structures indicates they do not appear to be widespread phenomenon.

The setting of many stands on cooler, north aspects at high elevations, the

structure of many stands with open understories, the presence of relatively large,

somewhat fire resistant individuals, and the natural patchiness of the landscape

tend to preclude fire-caused stand replacing events. Most stands probably

experience patchy burns with portions of the stand being completely consumed,
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 107

and others are left with little damage. Avalanche can replace stands on these

steep slopes. Most of these appear to be infrequent and occur at scattered

locations across the landscape. Understories, including smaller trees, generally

remain intact. Other disturbance elements such as windthrow, insects, disease,

and lightning do not appear to affect large areas in these stands. In most cases

disturbance occurs continuously at various scales, and this results in the creation

of gaps of various sizes with constantly changing structures through time.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. It does not appear these stands go

through a prolonged period in a grass/forb or shrub phase following disturbance,

but it also appears conifer establishment is a process that can occupy a

considerable period of time. Eventually regeneration becomes established in

openings created through disturbance, and it grows, self-thins, and matures

while other portions of the stand continue to undergo disturbance. In time,

several size classes, including a substantial portion of larger trees, are

represented, and the stand exhibits an irregular structure with many small

relatively even-aged patches. As stands occupy sites for longer periods,

successive disturbances continue to develop and maintain stand structures until

an infrequent stand replacing event occurs and a new stand emerges.

 Cover (percent) Mean Range

Total vegetative 68 38-85

Tree 65 37-81

Shrub 1 0-2

Forb 2 0-5

Grass 1 0-8

Moss 1 0-4

Stand age (years) 261 134-359

Diversity index

Simpson 0.44 0.27-0.86

Hill numbers

N0 8.6 4.0-14.0

N1 4.29 1.56-6.49

N2 2.49 1.17-3.68

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

TSME Mountain hemlock 100 37 10-74

PIMO3 Western white pine 82 11 1-27

ABMA Red fir 76 23 2-60

II. Understory trees

TSME Mountain hemlock 100 2 1-5

PIMO3 Western white pine 94 1 1-1

ABMA Red fir 82 3 1-13

PICO Lodgepole pine 24 1 1-1

III. Shrubs

None

IV. Forbs

ARPL Broad seeded rock cress 53 1 1-1
108 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

IV. PHHY Waterleaf phacelia 41 1 1-1

PESE3 Pine woods lousewort 35 1 1-1

HIAL White flowered hawkweed 29 1 1-1

V. Grasses and grass-like

POBO1 Bolander’s bluegrass 29 1 1-1

CAR-1 Sedge 24 1 1-1

CARO1 Ross’ sedge 24 1 1-1

POGR1 Pacific bluegrass 24 3 1-8

Soils

The predominant soils in this association are Inceptisols. Entisols were sampled

in a few cases. Most of the Inceptisols are Xerumbrepts and Xerochrepts, and the

most common great group in the Entisols are Cryorthents. Samples were typically

described as skeletal reflecting high coarse fragment contents in the profiles.

Samples occurred almost equally on granitic and volcanic parent materials; rare

samples occurred in metamorphic rocks and mixed materials. Soils are formed in

place from bedrock in about equal portions with those that are formed from

transported material such as alluvial and colluvial deposits and glacial tills.

Soils are moderately deep to deep. Most often depths exceed 40 inches, and

only on occasion are they less than 30 inches. Average topsoil depth is among the

lowest in the upper montane; many stands had topsoils of less than 7 inches, and

often they were less than 4 inches. Topsoils commonly contained more than 15

percent coarse fragments, and subsoils typically contained more than 35 percent

coarse fragments. Subsoil coarse fragments are considerably higher than those

on most other sites in the upper montane. Textures in the topsoil were evenly

distributed between gravelly sands, gravelly sandy loams, and gravelly loams.

Subsoils were usually sandy loams with some sands and loams.

The AWC of these soils is typically low. It results from coarse textures and

higher coarse fragment contents in the subsoils. Topsoil pH is substantially more

acid than many other sites. They reflect similar conditions in the mountain

hemlock association. Soils commonly lie over bedrock that is fractured and

rootable. They are often excessively drained, and erodibility is moderate to high

due to the steep slopes. These are cold soils; soil temperatures are considerably

lower than most other sites, and they are only slightly higher than temperatures

in the mountain hemlock association which has the lowest of any in the upper

montane. Summertime soil temperatures are often less than 49° Fahrenheit.

 Variable Mean Range

Depth of soil sample (inches) 35 22-40+

Topsoil

Depth (inches) 6 1-20

Coarse Frag. (pct) 32 1-75

pH 5.4 4.3-6.5

Subsoil

Coarse Frag. (pct) 48 1-88

pH 5.8 5.2-6.8

AWC (inches) 2.3 0.5-5.4

Temp (20 inches) (Fahrenheit) 47 39-54

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 109

Productivity

Pacific Southwest Region (Region 5) site indexes range from 2 to 5, but site

indexes in most stands are 2 or 3. Stand densities can be quite high. Generally,

stand density indexes are greater than 400, and they compare to those found in

dense red fir-white fir stands that are some of the densest in the upper montane.

Tree heights, however, are substantially shorter than most other associations due

to the presence of mountain hemlock, western white pine, and lodgepole pine,

which are shorter trees in the Sierra Nevada. Mountain hemlock ranged between

83 and 122 feet for larger individuals in these stands compared to the tallest red

fir of 152 feet. The net effect of shorter trees but higher densities is basal area

stocking and cubic and board foot volumes that are comparable to most other

densely forested stands in the upper montane although they are substantially

less than highly productive associations such as red fir or red fir-white fir.

Stands are irregular in structure. Quadratic mean diameters reflect the

presence of smaller trees in many stands. Compared to a balanced uneven-age

distribution with comparable stocking levels, trees up to 18 inches are well

represented, but the number of trees in size classes above 18 inches are excessive

(fig. 23). When compared to even-aged structures, trees smaller than 24 inches

and those larger than 30 inches are over represented. Diameters of large mountain

hemlock averaged 31 inches, and none were sampled that exceeded 45 inches.

Quadratic mean diameters averaged 18 inches, which is substantially below that

of most other dense, forested stands in the upper montane.

 Variable Mean Range

Region 5 site index 3 2-5

Forest survey site class 4 3-6

Stand density index 523 295-816

Quadratic mean diameter 17.8 12.1-31.8

Softwood volume (mcf/ac) 10.0 4.2-16.5

Softwood volume (mbf/ac) 59.8 22.5-118.9

Softwood basal area (sq ft/ac) 353 213-507

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Figure 23—Number of trees by

diameter class in the mountain

hemlock//steep plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

100

120

60

80

40

20

140
110 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 33 - 5 - 14 48

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag numbers are low in this association. Snags are distributed somewhat

uniformly among all size classes and species. Most are less than 20 feet tall, and

they appear to be sound. Snags in these stands generally lie in decay classes

between 1 and 3. Logs are commonly less than 30 inches in diameter reflecting

the presence of mountain hemlock. They are generally less than 50 feet long, and

often they are less than 20 feet in length. Logs exhibit higher levels of decay than

snags, and the majority occur in decay classes between 3 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0.6 0.3 0.5 0.4 0.8 2.6

Snag height (feet)

<20 - 0.6 0.2 0.5 - 0.4 1.7

20-50 - - - - - 0.1 0.1

>50 - - 0.1 - 0.4 0.3 0.8

Snag decay class

1 - - - - 0.4 0.2 0.6

2 - - - - - 0.5 0.5

3 - 0.3 0.2 0.5 - - 1.0

4 - 0.3 0.1 - - - 0.4

5 - - - - - 0.1 0.1

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 4.0 10.0 2.0 3.3 19.3

Log length (feet)

<20 2.7 6.0 0.7 1.3 10.7

20-50 1.3 4.0 0.7 0.7 6.7

51-100 - - 0.6 1.3 1.9

>100 - ----

Log decay class

1 -----

2 -----

3 2.0 4.0 0.7 0.7 7.4

4 1.3 2.0 0.7 1.3 5.3

5 0.7 4.0 0.6 1.3 6.6
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 111

Wildlife

Large game forage production appears to be quite low. Of the species present in

these stands only Ross’ sedge and Bolander’s bluegrass are staples, and it is

doubtful there is enough cover to provide any real forage. Deer use of these

stands, however, was common, and pocket gophers were observed in the

majority of stands.

Range

Range potential in this association appears to be transitory as livestock move to

primary range sites such as meadows and other moist habitats. The mountain

hemlock//steep plant association appears to be marginal from a range forage

standpoint. None of the more commonly found species on these sites are primary

or secondary forage species. In addition, the steep slopes that characterize these

stands would appear to preclude use by livestock. On the other hand, signs of

cattle use were common on these sites.

Management Recommendations

Most late seral stands have moderate levels of natural conifer regeneration

present, but in the few cases where logging or other disturbance has occurred, it

has had little effect on increasing conifer stocking levels. Stocking on many of

these sites generally results from established seedlings and saplings that survive

disturbance. It appears that stand establishment can be a fairly lengthy process in

this association. Time periods may exceed 25 to 30 years or more. Techniques for

planting mountain hemlock, western white pine, and red fir on these sites has

not been developed, and currently success rates from planting can be expected to

be low. Research has not been directed at appropriate cutting methods or stocking

levels for these stands, and early successional sequences after disturbance are not

well understood.

Stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable, but species composition and site

indexes are limiting, and the ability of sites to respond to treatment is uncertain.

The ability to predict results of treatment are not based on wide experience or

research results at this time. Intensive timber production is not recommended for

these sites. Where harvesting is scheduled, recommendations for cutting methods

would be those that rely on natural regeneration, and it appears best at this time

to conduct any silvicultural treatments in this type on a small scale and with

caution.

This plant association provides landscape level diversity through differences

in species composition and stand structures even though the species diversity

within a stand is not high. Appropriate management emphasis would maintain

this difference and the processes that create it as essential components in upper

montane forests.

USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 113

Mountain Hemlock Association

Tsuga mertensiana

TSME

CHMCHM12

Sample size: 32

Distribution

The mountain hemlock plant association is located throughout the range of

mountain hemlock in the Sierra Nevada; however, stands occur predominantly

north of the Kings River. In general, mountain hemlock as a species does not

extend much south of latitude 37° in the Sierra Nevada although isolated small

stands are reported as far south as latitude 36°37’. Samples in this association lay

generally north of latitude 37°30’ and west of longitude 119°. The most southerly

stand sampled was near Hatch lake east of Dinkey Creek on the Sierra National

Forest. This association then extends northward though the Eldorado National

Forest and the Lake Tahoe Basin Management Unit. In the north stands become

more common and larger in size. The association typically occurs as scattered,

relatively small stands that seldom exceed 25 acres and may be as small as a

fraction of an acre.

Environment

This is a higher elevation association. Although average elevations are not

unusually high for the range of the upper montane, it is located in the northern

portion of the study area where elevations of most plant communities are lower

than those to the south. Stands generally lie above 8,000 feet, and usually above

8,500 feet. Aspects are typically northeast, and most sites lie between northeast and

northwest. Few stands occur on south aspects. Slopes are gentle; all are less than 30

percent, and often they are less than 20 percent. Microrelief is commonly broken

and hummocky. Sites occur uniformly from upper to lower slope positions. Rarely,

however, are they located on ridge tops. These stands have significantly less bare
114 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

ground than stands in most other associations. SRI values are characteristically low

reflecting lower radiation levels from northerly aspects; however, this association

has substantially higher radiation indexes than the mountain hemlock//steep

association with which it often occurs. Stress indexes on these sites is typically

moderately high to high. This results in most cases from a combination of lower

AWC on specific sites in conjunction with locations on upper slopes.

Variable Mean Range

Elevation (feet) 8,390 7,380-9,160

Slope (pct.) 18 2-29

Solar radiation index 0.437 0.385-.533

Bare ground (pct.) 1 0-20

Surface gravel (pct.) 4 0-32

Surface rock (pct.) 9 0-43

Litter (pct.) 85 27-99

Litter depth (inches) 1.3 0.4-3.0

Stress index 0.50 0.38-0.60

Aspect: NE, NW.

Range: All.

Position: Upper, middle, lower slopes.

Range: All positions.

Vegetation

This association is a dense forest with open understories. The overstory is

dominated by mountain hemlock mixed with red fir and western white pine.

Lodgepole pine is an occasional member of the overstory. Both mountain

hemlock and western white pine are indicators of moderate to dry habitats. Trees

larger than 40 inches in diameter are generally predominant red fir which rise

above the main forest canopy. Stands in this association are often found

associated with the mountain hemlock//steep, red fir-western white pine, and

red fir associations on mesic sites.

Understory vegetation is sparse and dominated by moderate to moist site

indicators. Shrub and grass cover are considerably less than most other sites. Of the

few shrubs present, sierra gooseberry and alpine prickly currant are both moist site

indicators. Brewer’s golden aster and white flowered hawkweed in the forb layer

are common indicators of mesic sites, and Bolander’s bluegrass also indicates

somewhat moderate moisture regimes. Broad seeded rockcress and Ross’ sedge

are indicators of moderate to dry conditions. Moss occurs in this association

significantly more often compared to many other sites in the upper montane.

Conifer regeneration is high. The average number of seedlings per acre is

more than 1,000, and stands usually have more than 500 per acre. Red fir dominates

the regeneration followed by substantially lower numbers of mountain hemlock.

Western white pine and lodgepole pine are present in lesser amounts. Mountain

hemlock, western white pine, and lodgepole pine, on the other hand, are

regenerating with significantly higher frequency than in most other associations.

Plant species diversity is moderate. This association has a moderate number

of species overall, and sites are dominated by a relatively few tree species that far

outweigh cover values of the shrub, forb, and grass layers. Abundant species are

concentrated in the tree layer.

Most late seral stands contain trees that are older than 250 years, but average

stand ages were not substantially different than other stands in the upper

montane. The oldest tree sampled was a red fir estimated at +507 years although

a western white pine was estimated at +431 years, and a mountain hemlock was

recorded at +427 years.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 115

Large scale, stand replacing disturbances are probably uncommon in this

association. Although such events may occur, they do not appear to be widespread

phenomenon. The setting of many stands on cooler north aspects at high

elevations, the structure of stands with open understories, the presence of

relatively large, somewhat fire resistant individuals, and the natural patchiness of

the landscape tend to preclude fire-caused stand replacing events and ensure

some level of survival by most species after a fire. Most stands probably experience

patchy burns with portions of the stand being completely consumed, and others

are left with little damage. Avalanche can replace stands on middle and lower

slope positions, but it appears to be infrequent in late seral stands, and it occurs at

scattered locations across the landscape. Understory trees generally remain intact.

Other disturbance elements such as windthrow, insects, disease and lightning are

more common, but they generally occur in localized situations or on select species

and do not cause stand replacement in most cases. It is probable that disturbance

occurs continuously on various scales, and this results in the creation of various

sized gaps with constantly changing structures through time.

Stand development appears to be sporadic as opportunities for growth and

regeneration arise in response to disturbance. After disturbance, stands do not

appear to go through a prolonged period in a grass/forb or shrub phase. On the

other hand, it also appears conifer establishment is a process that can occupy a

considerable period of time. Regeneration generally becomes established in

openings created through disturbance, and it grows, self-thins, and matures as

other portions of the stand continue to undergo disturbance. In time, several size

and tree classes, including a substantial portion of larger trees, are represented,

and the stand exhibits an irregular structure with many small relatively evenaged patches. As stands occupy sites for longer periods, successive disturbances

continue to develop and maintain stand structures until an infrequent stand

replacing event occurs and a new stand emerges.

 Cover (percent) Mean Range

Total vegetative 77 23-97

Tree 68 22-88

Shrub 1 0-15

Forb 7 0-35

Grass 5 0-45

Moss 2 0-13

Stand age (years) 229 99-440

Diversity index

Simpson 0.37 0.12-0.71

Hill numbers

N0 11.2 4.0-21.0

N1 5.79 2.21-13.68

N2 3.27 1.40-8.69

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

TSME Mountain hemlock 100 23 4-75

ABMA Red fir 88 30 1-76

PIMO3 Western white pine 62 13 2-44

PICO Lodgepole pine 53 21 1-54
116 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

II. Understory trees

TSME Mountain hemlock 94 2 1-7

ABMA Red fir 78 4 1-17

PIMO3 Western white pine 75 1 1-2

PICO Lodgepole pine 38 1 1-2

III. Shrubs

RIMO Alpine prickly currant 22 1 1-1

RIRO Sierra gooseberry 22 1 1-2

IV. Forbs

CHBR3 Brewer’s golden aster 66 2 1-10

PESE3 Pine woods lousewort 50 1 1-3

HIAL White flowered hawkweed 34 2 1-12

ARPL Broad seeded rockcress 31 1 1-1

ERPEA Wandering daisy 28 5 1-16

V. Grasses and grass-like

CARO1 Ross’ sedge 56 2 1-8

LUCO1 Common woodrush 31 2 1-5

POGR1 Pacific bluegrass 31 2 1-10

POBO1 Bolander’s bluegrass 28 2 1-5

Soils

Typical soils are Inceptisols. Entisols and Alfisols are encountered in a few cases.

Most Inceptisols are Umbrepts; the remainder are Ochrepts. Entisols are usually

described as Psamments, and the Alfisols are distributed between Xeralfs and

Boralfs. Particle size classes were normally skeletal although a significantly

higher proportion of the samples were loamy compared to most other

associations. These soils developed primarily from granitic parent materials;

however, a few samples in the north were derived from volcanic or mixed

materials. The association occurs equally on soils that are formed in place from

bedrock or from deposited materials such as colluvium, alluvium, or glacial tills.

Soil depths are somewhat variable although modal sites are moderately deep

to deep. Profiles often exceed 35 inches in depth although, on occasion, they can

be less than 25 inches. Soil textures in the topsoil are typically sandy loams or

loams with occasional sands. Subsoil textures are usually sandy loams with some

sands and occasional loams. A significant portion of the topsoils in this

association are ochric, and a significant number of the subsoils are 7.5 YR with

low values and high chroma. Topsoils tend to be brownish yellow, and subsoils

tend to range from strong brown to light gray when moistened.

The AWC is usually low to moderately low but not substantially different

from most other sites in the upper montane. Topsoil pH is significantly more

acid than those in most other associations, and they reflect similar conditions in

the mountain hemlock//steep association. In most cases, stands lie over bedrock

formations that are fractured and rootable thus increasing potential rooting

depth and moisture supply. Sites are often well drained, but a relatively high

number are also excessively drained. Erodibility on these moderate slopes ranges

from low to high primarily in response to differences in soil textures. Average

summertime soil temperatures are the lowest of any in the upper montane. Soil

temperatures are typically less than 49° Fahrenheit.

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 117

 Variable Mean Range

Depth of soil sample (inches) 32 14-40+

Topsoil

Depth (inches) 8 0-26

Coarse frag. (pct.) 19 2-65

pH 5.3 4.5-6.4

Subsoil

Coarse frag. (pct.) 32 2-70

pH 5.9 4.8-6.7

AWC (inches) 2.8 0.7-5.3

Temp (20 inches) (Fahrenheit) 45 39-56

Productivity

These stands have a wide range of site indexes reflective of the variation in soil

depths. Most often Pacific Southwest Region (Region 5) site indexes are 2 and 3.

Rare stands have site indexes greater than 2, but occasional sites will have site

indexes of 4 or 5. Stand density can be quite high. This plant association has one of

the highest stand density indexes in the upper montane. Index values often exceed

500, and average values are exceeded only by the red fir-lodgepole pine/whiteflowered hawkweed association, which carries the highest density of any forested

association in the upper montane. Lower quadratic mean diameters reflect the

high number of trees in smaller size classes, and average heights of dominant trees

are significantly shorter than other dense forested plant associations due to the

presence of mountain hemlock, western white pine, and lodgepole pine in the

stands. The tallest mountain hemlock recorded was an estimated 123 feet tall, and

the tallest western white pine and lodgepole pine were measured at 126 and 110

feet respectively. These are compared to the tallest red fir measured at 174 feet.

Average stand diameters are also less than other high density forested stands. The

net effects of high stand density and shorter trees distributed on smaller diameter

trees are basal areas and cubic and board foot volumes that are comparable to

other forested stands in the upper montane, although they are somewhat less than

highly productive associations such as red fir and red fir-white fir.

Stand structures in general are irregular, although individual late seral stands

range from even to uneven-age distributions. Typically, they contain more trees

in both the smaller and larger size classes than would be the case in an even-aged

distribution, and they contain more trees in the larger size classes and fewer in

the smaller size classes than would be the situation in balanced uneven-age

distributions of similar stocking (fig. 24). Overall, stands approach an unevenaged distribution with excessive trees in size classes less than 18 inches.

 Variable Mean Range

Region 5 site index 3 1-5

Forest survey site class 4 2-6

Stand density index 541 141-1239

Quadratic mean diameter 18.6 7.2-34.6

Softwood volume (mcf/ac) 10.2 1.3-21.0

Softwood volume (mbf/ac) 64.1 11.9-124.8

Softwood basal area (sq ft/ac) 364 116-680

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
118 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 40 - 18 - 11 31

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag numbers are moderate. Mortality in late seral stands is concentrated in size

classes below 25 inches and appears to be related to thinning of suppressed

individuals. Mortality in the larger size classes seems to be related to senescence

and is randomly distributed among all species. Snags in the samples were

typically shorter than 50 feet, indicating a tendency of standing snags to break off

over time. They lie predominantly between decay classes 1 and 3. Logs are

commonly smaller than 30 inches reflecting the presence of mountain hemlock.

Most are less than 50 feet in length, and they show higher levels of decay than

snags. Log decay classes generally lie between 3 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 6.9 3.1 2.3 1.4 0.6 0.9 15.2

Snag height (feet)

<20 4.6 0.5 0.7 0.4 0.3 0.3 6.8

20-50 2.3 0.7 0.5 - - - 3.5

>50 - 1.9 1.1 1.0 0.3 0.6 4.9

Snag decay class

1 2.9 0.5 - 0.4 - 0.4 4.2

2 2.9 1.7 1.1 0.7 0.3 0.1 6.8

3 1.1 0.9 0.7 0.3 0.3 0.2 3.5

4 - - 0.5 - - 0.2 0.7

5 - - - - - --

Figure 24—Number of trees by

diameter class in the mountain

hemlock plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

100

120

60

80

40

20

140

160

180

200
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 119

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 6.2 13.1 4.7 1.8 25.8

Log length (feet)

<20 3.1 4.5 1.1 0.7 9.4

20-50 2.0 6.2 2.5 0.2 10.9

51-100 1.1 2.4 1.1 0.7 5.3

>100 - - - 0.2 0.2

Log decay class

1 0.2 - 0.2 - 0.4

2 - 0.9 0.4 0.4 1.7

3 2.9 3.8 1.6 - 8.3

4 1.8 4.2 1.6 0.7 8.3

5 1.3 4.2 0.9 0.7 7.1

Wildlife

These stands may offer some hiding and thermal cover to large game, but forage

possibilities appear transitory. Of the species present, only Ross’ sedge and

Bolander’s bluegrass are staples in the large game diet. They occur consistently

enough and with sufficient cover value to provide forage for marginal big game

use. Observation of deer sign was common, and evidence of pocket gopher use

was generally high in these stands.

Range

These are transitional range sites that are used by livestock to access primary

range sites such as meadows and other moist habitats. Sign of cattle use was

present in typical stands; however, none of the more commonly occurring species

on these sites are primary or secondary range forage species, and it would

appear range forage potential is low in these late seral stands.

Management Recommendations

Little harvesting has occurred in the mountain hemlock plant association. Where

harvesting has occurred, it has had little effect on increasing conifer stocking

levels. Stocking on many of these sites generally results from established seedlings

and saplings that survive timber harvest and site preparation. It appears that

natural regeneration and stand establishment can be a fairly lengthy process. Time

periods may exceed 25 to 30 years or more. Techniques for planting mountain

hemlock, western white pine, and red fir have not been developed in this

association, and currently success rates from planting attempts can be expected to

be low. Research has not been directed at appropriate cutting methods or stocking

levels for these stands, and early successional sequences are not well understood.

These stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable, but species composition is limiting,

and the ability of sites to respond to treatment is uncertain. The ability to predict

results of treatment are not based on wide experience or research at this time.
120 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Management for intensive timber production is not recommended. Where

harvesting is scheduled, recommendations for cutting methods and regeneration

strategies would be those that rely on natural regeneration. It would appear best

at this time to conduct any silvicultural treatments in this association on a small

scale and with caution.

This association provides landscape level diversity in these forests through

differences in species composition and stand structures even though the species

diversity within a stand is not high. It would therefore seem appropriate to

maintain this diversity and the processes that create it as essential components of

upper montane forests.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 121

Red Fir-Western White Pine/Pinemat Manzanita Association

Abies magnifica-Pinus monticola/Arctostaphylos nevadensis

ABMA-PIMO3/ARNE2

CFRCPW12111

Sample size: 31

Distribution

The red fir-western white pine/pinemat manzanita plant association is located

throughout the study area on both the westside and eastside of the range. All

stands were located north of 36° latitude and generally west of 118° longitude.

Stand size is usually not large; however, some sites were observed that appear to

be in the range of 100 acres or larger.

Environment

This is a high elevation association. Although the elevation range is wide, sites

characteristically lie above 8,000 feet, and seldom do they occur at lower elevations.

Stands do lie at significantly lower elevations than others in the western white

pine subseries, however. It differs from the red fir/pinemat manzanita plant

association with which it is comparable in many respects by occupying generally

higher elevation sites. Aspects are varied. Sample stands were generally quite

evenly distributed between aspects although a slightly higher portion was located

on southeast-and southwest-facing slopes. Stands lie predominantly on ridges

and upper to middle slope positions on sites with broken and varied microrelief.

Slopes commonly occur between 20 and 40 percent. Bare ground and surface rock

are both significantly higher than most other sites. Surface rock usually occupies

between 5 and 25 percent of the ground surface. Litter depths are also considerably

less than in many other associations. Stress indexes are characteristically high.

These reflect variations of shallow soils, lower water holding capacities, upper

slope positions, and solar radiation levels on specific sites.
122 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,364 7,200-9,120

Slope (pct.) 28 6-59

Solar radiation index 0.484 0.308-.565

Bare ground (pct.) 6 0-25

Surface gravel (pct.) 5 0-40

Surface rock (pct.) 11 0-65

Litter (pct.) 79 25-99

Litter depth (inches) 1.0 0.2-3.5

Stress index 0.54 0.42-0.65

Aspect: SE, SW.

Range: All.

Position: Upper and middle slopes.

Range: Ridgetops, upper and middle slopes, benches.

Vegetation

Stands are open woodlands with a picturesque understory of pinemat manzanita.

Total vegetation and shrub cover are higher than most other plant associations

due to the abundance of this species. Conversely, these stands have the lowest

tree cover of any western white pine association, and tree cover is substantially

lower than most other associations in the upper montane. Overstory composition

is characterized by higher levels of western white pine mixed with red fir which

serves to differentiate it from the red fir/pinemat manzanita plant association

that it resembles. Western white pine along with pinemat manzanita, broad

seeded rock cress, mountain pennyroyal, squirrel tail, and western needlegrass

are indicators of the generally dry habitats encountered on these sites.

Conifer regeneration is moderate to low, and it is usually clumped rather

than evenly distributed in the stand. The average number of seedlings is 450 per

acre, and seedling counts were commonly higher than 100. Occasional stands

contain more than 500 seedlings per acre. Regeneration is dominated by red fir

although western white pine is typically present. In some cases lodgepole pine is

also a component of conifer regeneration. Western white pine is regenerating

significantly more often than in most other associations.

Plant species diversity is also moderate. Most stands have a moderate

number of species overall compared to other forested stands in the upper

montane. Sites are dominated by relatively few tree species and a major shrub

layer. Together these outweigh cover values of the remaining forb and grass

layers. Abundant species are relatively few in number, and cover values are

somewhat uniformly distributed between trees and shrubs.

The oldest trees in these stands are generally older than 250 years. This

association carries high proportions of older trees, and average stand ages are

substantially older than most others in the upper montane. The oldest tree

sampled was a red fir at +519 years, and the oldest western white pine and

lodgepole pine were measured at +453 and +319 years, respectively.

Stand replacing events probably occur in this association, but they do not

appear to be frequent or large scale phenomena. The setting of many stands at

higher elevations, the structure of the stands with stocking concentrated in

widely spaced, relatively large, somewhat fire resistant individuals and the

discontinuous cover and low growth form of pinemat manzanita would tend to

preclude stand replacing fires. These stands probably experience patchy burns

with portions of the stand being consumed and others left with little damage.

Isolated large trees probably escape damage in most cases. Disturbance elements

such as windthrow, insects, disease, lightning, or avalanche do not appear to

affect large areas in these stands. It is likely that disturbance is occurring
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 123

continuously on various scales, and this results in the creation of various sized

gaps with constantly changing structures through time.

Reproductive strategies such as consistent seed production, sprouting, or

delayed germination of seed until scarified by fire is present in some of the species

on these sites. Red fir and western white pine are reasonably consistent seed

producers. Pinemat manzanita sprouts from stems, but it does not crown sprout.

Thus, patchy burns would ensure survival of at least some of these stems to allow

reoccupation of disturbed sites. In addition, the patchy distribution and wide

spacing of many of the existing trees would result in uneven coverage of sites by

most disturbance elements.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. Disturbance creates opportunities

for regeneration, but many microhabitats are unsuitable for regeneration, and

conifer establishment is often a prolonged process. Disturbance provides

opportunities for surviving individuals to increase growth. Isolated patches of

conifers that escape repeated disturbance proceed through periods of crown

closure and self thinning. Other portions of the stand continue to undergo

disturbance although there are probably always isolated trees and small patches

that escape and mature into larger individuals. In time, the stand develops an

irregular structure reflecting numerous disturbances, and containing scattered

large trees as survivors of these disturbance events.

 Cover (percent) Mean Range

Total vegetative 69 30-100

Tree 43 11-79

Shrub 31 2-82

Forb 3 0-25

Grass 2 0-9

Moss 0.2 0-2

Stand age (years) 275 168-410

Diversity index

Simpson 0.37 0.11-0.74

Hill numbers

N0 9.6 3.0-20.0

N1 4.03 1.85-9.50

N2 3.12 1.35-8.76

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

PIMO3 Western white pine 94 12 1-41

ABMA Red fir 90 29 3-68

II. Understory trees

ABMA Red fir 84 2 1-20

PIMO3 Western white pine 61 1 1-1

PICO Lodgepole pine 23 1 1-2

III. Shrubs

ARNE2 Pinemat manzanita 100 28 1-78

CASE3 Sierra chinquapin 23 3 1-7
124 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

IV. Forbs

ARPL Broad seeded rock cress 77 1 1-2

PESE3 Pine woods lousewort 61 1 1-2

MOOD Mountain pennyroyal 32 1 1-5

CHBR3 Brewer’s golden aster 29 2 1-5

V. Grasses and grass-like

SIHY Bottle brush Squirreltail 40 2 1-5

STOC1 Western needlegrass 40 1 1-2

CARO1 Ross’ sedge 30 1 1-2

Soils

Soils are predominantly Inceptisols and Entisols although stands include a

substantially higher proportion of Entisols than most other associations in the

upper montane. Considerable variation occurs among these soils below the

suborder level. Samples were distributed evenly between Umbrepts, Ochrepts,

Orthents, and Psamments. Particle size classes are commonly skeletal and

indicate somewhat higher levels of coarse fragments throughout the profile.

Parent materials are predominantly granite, and soils are usually formed in place

from bedrock. A few soils are formed from materials that have been deposited

such as glacial till or alluvium.

Soil depths are moderately deep to deep, but average depths are considerably

less than in many other associations. Typical depths were less than 35 inches,

and, some were less than 25 inches. Topsoil depths are also shallow. Topsoils

were commonly less than 7 inches, and occasionally they were less than 4 inches

deep. These are coarse to moderately coarse textured soils. Most frequently

topsoil textures were sands or sandy loams. Loams were seldom encountered.

Subsoil textures were also evenly divided between sands and sandy loams.

Subsoil colors are significantly different from most other associations. They

characteristically have 10 YR hues, but values are consistently high, and colors

range from gray to brownish yellow when moist.

The AWC in these stands is among the lowest in the upper montane. It is

significantly lower than on most other sites. Bedrock formations were usually

fractured and rootable thus supplying additional sources of moisture to the site.

Many sites are well drained, but drainage can also be excessive. Erodibility is low

to moderate reflecting coarse soil textures and moderate slopes. Stress indexes

are considerably higher than most other sites in the upper montane due to lower

AWC resulting from coarse textured and somewhat shallow soils, and the upper

slope positions common to these sites.

 Variable Mean Range

Depth of soil sample (inches) 31 8-40+

Topsoil

Depth (inches) 6 2-11

Coarse frag. (pct.) 19 5-38

pH 5.7 4.4-6.5

Subsoil

Coarse frag. (pct.) 45 10-86

pH 5.9 4.7-6.8

AWC (inches) 2.1 0.3-4.4

Temp (20 inches) (Fahrenheit) 51 41-60

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 125

Productivity

Pacific Southwest Region (Region 5) site indexes are considerably lower than

dense, well-stocked stands elsewhere in these forests. No site index was higher

than 2, and commonly samples had site indexes of 4 and 5. Stand densities are

moderately low. Stand density indexes are typically less than 300. They are

substantially lower than adjacent dense forested stands. Based on stand density

indexes stocking levels attain about 50 percent of values reached in dense forested

types in the upper montane. Stocking resides in the larger individuals of the

stand. The average quadratic mean diameter is larger in this association than

typical red fir stands that are stocked with many large trees per acre. Average

tree heights are also considerably less than many other associations reflecting

overall lower site quality and the presence of western white pine, a shorter tree,

in stands. The tallest red fir in this association was 159 feet compared to the

tallest western white pine at 115 feet. This combination of factors result in lower

cubic and board foot yields from this association.

Stands tend to be open with few trees per acre overall and stocking that is

concentrated in large trees (fig. 25). Compared to an uneven-aged stand with a

balanced diameter distribution and similar stocking levels, these stands have too

few trees in size classes smaller than 18 inches, and an excess of trees in size

classes larger than 30 inches. Compared to an even-age distribution, they have an

excess of trees in both smaller and larger size classes.

 Variable Mean Range

Region 5 site index 4 2-5

Forest survey site class 5 3-6

Stand density index 274 124-482

Quadratic mean diameter 25.4 11.7-37.9

Softwood volume (mcf/ac) 6.1 2.5-12.9

Softwood volume (mbf/ac) 39.9 15.1-94.9

Softwood basal area (sq ft/ac) 196 5-400

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Figure 25—Number of trees by

diameter class in the red fir-western

white pine/pinemat manzanita plant

association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

14

16

8

6

10

12

4

2

18

20

22

24

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 63 - 10 2 25 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -
126 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Coarse Woody Debris

Snag numbers are moderate to low, but they are distributed more or less

uniformly across all size classes. Mortality is distributed among all species.

Snags are typically shorter than 50 feet in height indicating a tendency of large

standing snags to break off over time. All decay classes are represented but most

snags sampled occurred in classes 3 to 5. Logs are usually smaller than 30 inches,

and lengths less than 50 feet predominate. Logs evidence somewhat higher levels

of decay compared to snags, and decay classes 4 and 5 are typical.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0.8 0.9 0.8 0.6 0.7 0.7 4.5

Snag height (feet)

<20 0.8 0.2 0.2 0.2 0.5 - 1.9

20-50 - 0.2 0.3 - 0.2 0.7 1.4

>50 - 0.5 0.3 0.4 - - 1.2

Snag decay class

1 - - 0.3 0.2 - - 0.5

2 - 0.7 - - 0.1 - 0.8

3 0.8 0.2 0.3 0.2 0.2 - 1.7

4 - - 0.1 0.2 0.2 0.7 1.2

5 - - 0.1 - 0.2 - 0.3

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 4.7 14.0 5.8 1.1 25.6

Log length (feet)

<20 4.3 7.5 2.0 0.9 14.7

20-50 0.4 5.8 2.5 - 8.7

51-100 - 0.7 1.3 0.2 2.2

>100 - ----

Log decay class

1 -----

2 - 0.7 - 0.2 0.9

3 0.7 2.2 1.6 - 4.5

4 2.4 4.7 1.8 0.7 9.6

5 1.6 6.4 2.4 0.2 10.6

Wildlife

Forage values appear to be low and concentrated in the scattered grass component.

Of the species occurring on these sites, bottle brush squirreltail, western

needlegrass, and Ross’ sedge are staples in the big game diet. They occur with

moderate frequency but low cover values, and they would appear not to be major

contributors to the large game diet. On the other hand, deer use was generally

observed on these sites, and pocket gophers were usually present as well.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 127

Range

These are transitional range sites that are used by livestock to access primary

range sites such as meadows and other moist habitats. Nevertheless, cattle

evidence was common on these sites. Squirreltail and western needlegrass are

secondary livestock forage species; however, the moderate constancy and low

cover would appear to preclude these sites from heavy livestock use. It appears

livestock forage potential is low in these late seral stands.

Management Recommendations

Relatively few stands in this type have been harvested. As a consequence,

silvicultural systems, cutting methods, regeneration strategies, early successional

sequences, and stocking levels important in the management of any forested

type are relatively unknown. Where stands have been harvested and disturbance

has occurred, regeneration patterns are unclear at this time. No sites were

observed where stands were harvested, sites prepared, and planting has occurred

with any systematic approach.

These stands have limited productive capacity and flexibility for stand

management. The open nature of these stands indicates that regeneration and

establishment is a lengthy and variable process under most conditions.

Recommendations for harvesting at the present time would be to treat stands in

this association with caution and the expectation that results can be uncertain.

Limited opportunities exist for salvage when it occurs, but on these open sites it

would appear that woody debris left in the form of snags and logs for wildlife or

part of the nutrient pool would be better direction for this association.

Management emphasis should provide for existing wildlife habitat, plant species

richness, and the landscape level diversity this association provides to upper

montane forests.

USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 129

Abies magnifica-Pinus monticola/Castanopsis sempervirens

ABMA-PIMO3/CASE3

CFRCPW14

Sample size: 11

Distribution

The red fir-western white pine/Sierra chinquapin plant association is located at

higher elevations primarily in the southern and eastern portions of the study

area. Sample sites were located on the Sequoia, Inyo, and Toiyabe National

Forests, but it is likely the association extends further, and sites have been

observed but not sampled in Yosemite National Park on the westside. Stand size

is usually quite small. In many cases stands cover only fractions of an acre on

rock outcrops; however, some sites appear to be larger than 50 acres such as

those near Sherman Pass on the Sequoia National Forest.

Environment

This is a high elevation plant association. Stands characteristically lie above 8,000

feet, and many occur above 8,500 feet. Higher elevations reflect locations in the

southern and eastern portions of the study area. Aspects are predominantly

northeast and northwest, and the majority of stands are located on upper and

middle slopes that exceed 30 percent. Average slopes are considerably steeper

than most other associations in the upper montane. Solar radiation levels are

generally moderately low to low reflecting steeper slopes and northerly aspects.

Micro relief is evenly distributed between sites that are uneven and broken and

those which are uniform. Stress indexes are moderately high to high resulting

from lower AWC and upper slope positions.

Red Fir-Western White Pine/Sierra Chinquapin Association
130 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,696 8,000-9,200

Slope (pct.) 39 25-65

Solar radiation index 0.438 0.328-.552

Bare ground (pct.) 3 0-10

Surface gravel (pct.) 6 0-15

Surface rock (pct.) 18 1-60

Litter (pct.) 73 28-89

Litter depth (inches) 1.3 0.5-2.7

Stress index 0.52 0.46-0.56

Aspect: NE, NW.

Range: All.

Position: Upper and middle slopes.

Range: Ridgetops, upper and middle slopes.

Vegetation

Stands are open woodlands with a prominent shrub understory. Shrub cover is

significantly higher than most other associations due to the abundance of Sierra

chinquapin. Overstory composition is characterized by western white pine mixed

with red fir. In some stands western white pine may attain cover as high as 30

percent, but in most cases red fir is the dominant species. Jeffrey pine and white

fir are occasional members of stands. Western white pine indicates the drier

conditions within this association.

Understories are dominated by Sierra chinquapin in the shrub layer. In some

cases greenleaf manzanita is present, and understories appear as a mixed shrub

plant community. Both Sierra chinquapin and greenleaf manzanita, however,

indicate the drier conditions that prevail on these sites. The forb layer is

composed of widely scattered rock cress and an occasional Sierra wallflower.

These two species also indicate dry to moderately dry habitats. A single grass

species, western needlegrass, occurs with reasonably high constancy, and it, too,

indicates drier conditions.

Conifer regeneration is low. The average number of seedlings per acre is

slightly more than 125, and often seedling counts are less than 100 trees per acre.

Red fir is generally present, but western white pine is only present on some sites,

and it occurs in low numbers. Nevertheless, western white pine is regenerating

significantly more often in this association.

Plant species diversity is also low. Stands tend to have few species overall,

and sites are dominated by relatively few tree species and a shrub layer. The

species in these two layers outweigh the cover values of the forb and grass layers.

Abundant species are few in number and distributed somewhat uniformly

between trees and shrubs on these sites.

The oldest trees in these stands are generally older than 250 years although

the average age of stands is not substantially different from most others in the

upper montane. The oldest tree sampled was a western white pine at +364 years,

and the oldest red fir was estimated at +360 years.

Stand replacing disturbances are probably uncommon in this association.

The shrub layer favors larger more intense fires, but non-uniform cover in the

shrub layer, the setting of many stands on cooler north aspects at high elevations,

the structure of the stands with stocking concentrated in relatively large, widely

spaced trees, and the natural patchiness of upper elevation stands, tends to

preclude large scale, intense fires. These stands probably experience patchy

burns with portions of the stand being completely consumed and others left with

little damage. Isolated large trees probably escape damage in most cases.

Disturbance elements such as windthrow, insects, disease, lightning, or avalanche
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 131

do not appear to affect large areas in these stands, and they do not generally

result in stand replacement.

Reproductive strategies such as consistent seed production or sprouting are

present in some species on these sites. Both western white pine and red fir

consistently produce seed crops from relatively early ages, and Sierra chinquapin

is a sprouting species in the shrub layer. The patchy nature of vegetation within

stands results in uneven coverage of sites by many of the disturbance elements,

and many plants are left undamaged.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to multiple disturbances. Disturbance creates

opportunities for regeneration, but many micro habitats are unsuitable for conifer

regeneration, and conifer establishment can be a prolonged process on these sites.

Isolated patches of conifers that escape repeated disturbance proceed through

periods of crown closure and self-thinning. Isolated trees and small patches that

escape disturbance eventually mature into larger members of the stand. In time,

the stand develops an irregular structure reflecting numerous disturbances, and

containing large trees as the survivors of several stand-altering events.

Cover (percent) Mean Range

Total vegetative 70 40-95

Tree 51 26-81

Shrub 29 2-85

Forb 9 0-40

Grass 1 0-4

Moss 0.3 0-1

Stand age (years) 248 142-362

Diversity index

Simpson 0.31 0.15-0.51

Hill numbers

N0 8.8 4.0-19.0

N1 4.49 2.37-9.56

N2 3.72 1.98-6.48

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

PIMO3 Western white pine 100 13 2-27

ABMA Red fir 100 27 12-52

PIJE Jeffrey pine 36 9 3-19

ABCO White fir 27 22 1-54

II. Understory trees

ABMA Red fir 100 1 1-1

PIMO3 Western white pine 36 1 1-1

III. Shrubs

CASE3 Sierra chinquapin 91 19 3-45

IV. Forbs

ARPL Broad seeded rock cress 73 1 1-1

PECA5 Cushion penstemon 36 1 1-2

PYPI White veined wintergreen 36 1 1-1

ERPE3 Sierra wallflower 27 1 1-2

V. Grasses and grass-like

STOC1 Western needlegrass 55 2 1-4
132 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Soils

Soils are predominantly Entisols, and they normally fall into two great groups:

Xerorthents and Xeropsamments. Particle size classes are commonly skeletal with

the remainder being sandy. These classifications are indicative of the relatively

high level of coarse fragments throughout the profiles but particularly in the

subsoils. Parent materials are generally granitic, but occasional tephra deposits

and metamorphic parent materials are also encountered reflecting locations in the

south and eastside. Soils in this association are evenly distributed between those

formed in place from bedrock and those formed from materials that were deposited

as alluvium.

Soil depths are moderately deep to deep. Profiles often exceeded 35 inches, but

only on occasion were they deeper than 40 inches. Average topsoil depths are

among the shallowest of any in the forested portions of the upper montane.

Commonly, topsoils are less than 7 inches, and sometimes depths are less than 4

inches. Textures in all horizons are typically sands with an occasional sandy loam.

Coarse fragments in the subsoils tend to be high. Normally they exceed 50 percent.

The AWC on these sites is characteristically low. This association has the

lowest average AWC of any in the upper montane. Bedrock is generally fractured

and rootable thus supplying additional sources of moisture to the site. Generally,

soils in this association are also excessively drained. Erodibility is moderate due to

the coarse textures in the surface soils. These soils are substantially more acid in

the subsoil than most other sites. Average summertime soil temperatures are

significantly warmer than most other forested sites in the upper montane. They

often exceed 53° Fahrenheit.

 Variable Mean Range

Depth of soil sample (inches) 33 25-40+

Topsoil

Depth (inches) 6 2-8

Coarse frag. (pct.) 24 2-60

pH 6.2 5.8-6.9

Subsoil

Coarse frag. (pct.) 43 7-75

pH 5.6 4.8-6.3

AWC (inches) 2.0 0.9-2.8

Temp (20 inches) (Fahrenheit) 53 45-57

Productivity

Site indexes are considerably lower than dense stands elsewhere in these forests.

Pacific Southwest Region (Region 5) site indexes are commonly 3 or 4, but few are

higher than 2. Stand densities are low. Sites generally carry fewer than 100 trees

per acre in all size classes. Stand density indexes are usually less than 300, and

stocking levels in this association reach only about 50 percent of the stocking

attained in dense forests of the upper montane. This stocking resides on the larger

individuals of the stand. Average quadratic mean diameters are among the largest

in the upper montane indicative of stocking that is concentrated in larger trees on

most sites. Tree heights are also substantially shorter, reflecting overall lower site

quality and the presence of western white pine, a shorter tree, in the stands. The

combination of lower site index, lower stand density, and shorter trees results in

moderately low basal area stocking and cubic and board foot yields.

These stands tend to be open with few trees per acre (fig. 26). Compared to

uneven-age distributions with similar stocking levels, these stands have far
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 133

too few trees in size classes smaller than 18 inches, and an excess of trees in

size classes larger than 30 inches. Compared to an even-age distribution,

these stands have an excess of trees in both smaller and larger size classes.

 Variable Mean Range

Region 5 site index 3 1-5

Forest survey site class 4 2-6

Stand density index 287 196-417

Quadratic mean diameter 26.2 13.4-35.3

Softwood volume (mcf/ac) 7.3 3.5-10.6

Softwood volume (mbf/ac) 48.4 21.8-72.6

Softwood basal area (sq ft/ac) 229 120-320

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Figure 26—Number of trees by

diameter class in the red fir-western

white pine/Sierra chinquapin plant

association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

14

8

6

10

12

4

2

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 60 11 3 5 21 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag numbers are low indicating the open stand conditions of this association.

Snags are distributed primarily in two size classes: those between 18 and 25

inches and those larger than 30 inches, but this is reflective of a generally low

number of sample snags in these open stands. Mortality appears to be randomly

distributed among all species. Most snags are less than 50 feet in height indicating

a tendency for large standing snags to break off over time. They frequently occur

in decay classes between 1 and 3. Logs are distributed across all size classes, but

most occurred in size classes less than 30 inches. The majority of logs are less

than 50 feet in length, and they show higher levels of decay than snags. Log

decay classes are typically 4 and 5.
134 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0 0.7 0 0.2 0.4 1.3

Snag height (feet)

 <20 - - 0.4 - - 0.2 0.6

20-50 - - - - 0.2 0.1 0.3

>50 - - 0.3 - - 0.1 0.4

Snag decay class

1 - - - - - --

2 - - 0.4 - - 0.2 0.6

3 - - - - 0.2 0.1 0.3

4 - - 0.3 - - 0.1 0.4

5 - - - - - --

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 7.0 7.0 2.0 4.0 20.0

Log length (feet)

<20 5.0 3.0 - 2.0 10.0

20-50 1.0 2.0 2.0 2.0 7.0

51-100 1.0 2.0 - - 3.0

>100 - ----

Log decay class

1 -----

2 1.0 1.0 - - 2.0

3 2.0 2.0 - - 4.0

4 2.0 2.0 - 2.0 6.0

5 2.0 2.0 2.0 2.0 8.0

Wildlife

Forage values appear to be low. Of the species commonly occurring on these

sites only western needlegrass is a staple in the big game diet. It occurs with

moderate frequency and cover, and it appears to offer only transitory forage

possibilities for large game. On the other hand, evidence of deer presence was

generally observed in these stands, and signs of pocket gophers were usually

encountered as well.

Range

These are transitional range sites that are used by livestock to access primary

range sites such as meadows and other moist habitats. Cattle evidence was

common in these stands. Western needlegrass is a secondary range species that

occurs with moderate constancy and cover. Other shrub, forb, and grass species

occurring on these sites, however, are of low value for forage, and it would

appear range forage potential is low in these late seral stands.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 135

Management Recommendations

Relatively few stands in this plant association have been harvested. As a

consequence, silvicultural systems, cutting methods, regeneration strategies,

successional sequences and stocking levels important in the management of any

forested stand are relatively unknown. Where stands have been harvested and

disturbance has occurred, regeneration patterns are unclear at this time. No sites

were observed where harvesting, site preparation, and planting has occurred

with any systematic approach.

These stands have limited productive capacity and flexibility for stand

management. The open nature of these stands indicates that regeneration and

establishment is a lengthy and variable process under most conditions.

Recommendations for harvesting at the present time would be to treat stands in

this association with caution and the expectation that results can be uncertain.

Limited opportunities exist for salvage when it occurs, but on these open sites it

would appear that woody debris left in the form of snags and logs for wildlife or

part of the nutrient pool would be better direction. Management emphasis

should provide for existing wildlife habitat, plant species richness, and the

landscape level diversity this association provides to upper montane forests.

USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 137

Red Fir-Western White Pine-Lodgepole Pine Association

Abies magnifica-Pinus monticola-Pinus contorta

ABMA-PIMO3-PICO

CFRCPW13

Sample size: 25

Distribution

The red fir-western white pine-lodgepole pine plant association straddles the

Sierra crest at high elevations throughout the range. Most samples were located

on the Inyo and Toiyabe National Forests, but they also occurred at high

elevations on the westside. Latitudes were generally north of 37°, and longitudes

were generally west of 119°. The most southerly sample was located on the Kern

Plateau near Monache Meadows. Stands can be extensive in size, but in most

cases, they are smaller than 100 acres.

Environment

Elevations commonly lie above 8,500 feet. This association differs from other

stands in the western white pine subseries by occurring at significantly higher

elevations, and it occurs at higher elevations than most other plant associations

in the upper montane in general. The lowest stand sampled was at 7,640 feet on

the Toiyabe National Forest, and the highest was at 9,640 feet on the Inyo

National Forest. Most frequently, aspects are northeast and northwest, but south

aspects are not uncommon. Slopes are varied and evenly distributed between

those that are less than 20 percent and those that are steeper; however, stands can

occupy slopes that are quite steep in some cases, and a substantial proportion lie

on slopes greater than 40 percent. Stands are typically located on ridges and

upper to middle slopes. Rarely are they located on lower slope positions.

Microrelief is variable and evenly distributed between sites that are uneven and

broken and those that are uniform. This association has significantly higher

levels of exposed gravel compared to most other sites. Solar radiation levels are

considerably lower than other sites reflecting steep north aspects in many stands.
138 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,602 7,360-9,640

Slope (pct.) 24 3-65

Solar radiation index 0.441 0.319-0.541

Bare ground (pct.) 2 0-12

Surface gravel (pct.) 10 0-55

Surface rock (pct.) 9 0-50

Litter (pct.) 76 17-99

Litter Depth (inches) 1.1 0.6-2.2

Moisture index 0.83 0.52-1.13

Stress index 0.50 0.39-0.60

Aspect: NE, NW.

Range: All.

Position: Ridges and upper and middle slopes.

Range: Ridgetops, upper, middle, lower slopes, and benches.

Vegetation

Stands are moderately dense forests with sparse understories. Tree cover is

generally less than other dense forested stands, and total shrub and forb cover

are substantially less than other plant associations in the upper montane. The

overstory is a mix of western white pine and lodgepole pine with scattered red fir

predominants. Western white pine or lodgepole pine rarely have cover values

greater than 30 percent individually, but it is the mix of species, and the higher

cover of both that distinguishes these stands from other associations. Stands

commonly occur with the mountain hemlock and lodgepole pine plant

associations on mesic sites, and together they mark the transition into the

subalpine forests above. Western white pine is generally a dry site indicator, but

lodgepole pine and red fir generally indicate mesic conditions. It is the presence

of all species that indicate the dry to mesic conditions present on these sites.

The shrub layer is essentially nonexistent. The forb and grass cover are also

quite low, but the species present are indicative of dry to moderate conditions.

Thus, broad seeded rock cress occurs on drier sites, and white veined wintergreen

indicates moderate sites. Ross’ carex, a moderate to dry site indicator, is usually

present in the grass layer as well as western needlegrass, a dry site indicator.

Conifer regeneration is moderate to high. The average number of seedlings

per acre is nearly 900, and stands generally have some regeneration present. Red

fir is the most common species regenerating, and western white pine and

lodgepole pine are present in substantially lower numbers. Nevertheless, western

white pine and lodgepole pine are regenerating significantly more often on these

sites compared to most other associations. Both species are also regenerating

with higher frequency than in any other western white pine association.

Plant species diversity in this plant association is moderate. Most stands

have a moderate number of species overall; however, stands are dominated by

relatively few tree species, and these outweigh the cover values of the shrub,

forb, and grass layers in the majority of cases. Abundant species are relatively

few in number and distributed predominantly in the tree layer.

The oldest trees in these stands are typically older than 250 years, but average

stand ages are not substantially different than most others in the upper montane.

The oldest tree sampled was a red fir at +459 years. This compares with the oldest

western white pine at 399 years and the oldest lodgepole pine at 308 years.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 139

Stand replacing events probably occur in this association, but they do not

appear to be frequent or large scale phenomena. The setting of many stands on

cooler north aspects at high elevations, the structure of the stands with open

understories, the presence of relatively large, somewhat fire resistant individuals,

and the natural patchiness of the landscape tend to preclude stand replacing

fires. Stands probably experience patchy burns with portions of a stand being

completely consumed while others are left with little damage. Avalanche can

replace stands on middle slopes in this association. Most of these appear to be

infrequent and occur at scattered locations across the landscape. Understories

generally remain intact. Other disturbance elements such as windthrow, insects,

disease, or lightning also do not appear to affect large areas in these stands.

Reproductive strategies such as reasonably constant seed production are

present in most of the tree species on these sites. Red fir and western white pine are

reasonably consistent seed producers, and lodgepole pine often produces abundant

seed. Shade intolerant species such as western white pine and lodgepole pine are

undoubtedly maintained by disturbances that open stands and provide seed beds.

Few trees in this association appear to originate as a result of a single

disturbance event that uniformly covers the site. Stand development appears to

be sporadic as opportunities for regeneration and growth arise in response to

disturbance. After disturbance, stands do not go through a prolonged period in a

grass/forb or shrub phase, but in most cases conifer regeneration is a process

that can occupy a considerable period of time. Once regeneration is established,

it grows, self thins, and matures. In time, several size and tree classes, including

a substantial portion of larger trees, are represented, and the stand exhibits an

irregular structure with many small relatively even-aged patches. As stands

occupy sites for longer periods, successive disturbance continues to maintain

stand structures until an infrequent stand replacing event occurs and a new

stand emerges.

 Cover (percent) Mean Range

Total vegetative 73 48-99

Tree 63 37-91

Shrub 1 0-12

Forb 9 1-40

Grass 5 0-33

Moss 0.2 0-2

Stand age (years) 242 109-369

Diversity index

Simpson 0.36 0.19-0.65

Hill numbers

N0 10.2 3.0-19.0

N1 4.11 1.74-7.50

N2 3.10 1.54-5.31

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

PIMO3 Western white pine 96 16 4-33

PICO Lodgepole pine 88 21 2-48

ABMA Red fir 84 33 1-84
140 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

II. Understory trees

PIMO3 Western white pine 88 1 1-2

ABMA Red fir 88 4 1-25

PICO Lodgepole pine 72 1 1-3

III. Shrubs

None

IV. Forbs

ARPL Broad seeded rock cress 72 1 1-5

PESE3 Pine woods lousewort 52 2 1-15

PYPI White veined wintergreen 32 1 1-1

CHBR3 Brewer’s golden aster 24 1 1-2

LUAN2 Anderson’s lupine 20 10 1-35

V. Grasses and grass-like

CARO1 Ross’ sedge 64 2 1-10

STOC1 Western needlegrass 36 2 1-8

POGR1 Pacific bluegrass 32 5 1-25

PONE1 Hooker’s bluegrass 20 1 1-2

Soils

Soils are Entisols and Inceptisols, and although Inceptisols are often present,

significantly higher proportions of Entisols are encountered compared to most

other associations. Taxonomically, these soils are variable at the suborder and

great group levels. Orthents occurred in the highest number of samples with

nearly 38 percent, but the remaining samples were distributed between Umbrepts,

Ochrepts, and Psamments. Particle size classes show similar variation. They tend

to be skeletal, but sandy, loamy, and ashy size classes also occur often, and

collectively they are more common than skeletal size classes. Parent materials too

are derived from a variety of sources. Thus, samples were often found on granitic

parent materials, but a significant proportion occurred on the volcanic flows and

lahars of the north and the tephra and ash deposits of the Mammoth Mountain

region. Soils are formed in place from bedrock or in almost equal portions from

colluvial deposits.

These soils are moderately deep to deep. Seldom were they less than 25

inches, and commonly they were deeper than 40 inches. Topsoil depths, however,

are among the shallowest of any in the forested portions of the upper montane.

Topsoils are commonly less than 7 inches, and on some sites depths were less

than 4 inches. Textures in the topsoil are usually gravelly sands with occasional

sandy loams. Subsoil textures are similar except they contain an even higher

proportion of sands. Soils in this association are significantly sandier in all

horizons than most others in the upper montane. Subsoil colors are primarily 10

YR in hue, but they have significantly higher values than most other associations.

Such subsoils range from light brownish gray to brownish yellow when moist.

The AWC of these sites is frequently low due to the coarse textured soils,

although average water holding capacities are not substantially lower than in

many other associations. Parent materials are characteristically fractured and

rootable and provide additional sources of moisture to these stands. The majority

of sites are excessively drained, and erodibility is low to moderate due to coarse

soil textures. As slopes increase above 30 percent, erodibility on these soils

becomes moderate to high.

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 141

 Variable Mean Range

Depth of soil sample (inches) 35 19-40+

Topsoil

Depth (inches) 6 3-16

Coarse frag. (pct.) 28 5-95

pH 5.9 4.8-6.5

Subsoil

Coarse frag. (pct.) 38 1-87

pH 5.9 5.0-7.2

AWC (inches) 2.7 0.6-5.5

Temp (20 inches) (Fahrenheit) 50 34-64

Productivity

Site indexes are variable, but they are generally lower than most other stands in

the study area. Pacific Southwest Region (Region 5) site indexes were commonly

3 or 4, but often they were as low as 4 or 5, and rarely better than 3. Stand

densities are moderate to high compared to other dense forested stands in the

upper montane. Stand density indexes are usually greater than 400, and based on

stand density indexes, stocking levels can be as high as 80 percent of those

reached in fully stocked stands of the red fir-white fir association, one of the

densest in these forests. Tree heights and average stand diameters are

considerably smaller than many other stands, reflecting the presence of shorter

and smaller diameter western white pine and lodgepole pine. The tallest western

white pine and lodgepole pine, for example, measured 110 feet and 100 feet,

respectively, compared to the tallest red fir of 150 feet. The quadratic mean

diameter is also substantially less than most other dense forested stands reflecting

a higher number of small trees that is often present. Yields resulting from this

combination of factors are considerably lower than typical red fir or red fir-white

fir stands in the study area.

Although many stands appear even-aged, this association in general

approximates an uneven-aged distribution (fig. 27); however, as is typical for

most stands in these forests, when compared to uneven-aged stands with similar

stocking levels and balanced diameter distributions, they have a deficit of trees

in size classes smaller than 18 inches. Compared to an even-age distribution with

equivalent stocking levels, both smaller size classes and larger size classes are

over-represented.

 Variable Mean Range

Region 5 site index 4 2-5

Forest survey site class 5 3-6

Stand density index 425 114-659

Quadratic mean diameter 18.2 8.9-30.7

Softwood volume (mcf/ac) 7.0 2.0-15.2

Softwood volume (mbf/ac) 42.0 11.0-105.3

Softwood basal area (sq ft/ac) 287 88-453

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
142 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 43 1 31 - 23 1

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - 1 - -

Coarse Woody Debris

Snag numbers are moderate to low. Mortality is distributed across all size classes

and species. It appears to be related to thinning in smaller size classes and

senescence in larger size classes. Snags are commonly shorter than 50 feet

indicating a tendency of larger standing snags to break off over time. Most lie in

decay classes between 1 and 3. Logs are distributed in all size classes as well, but

many are smaller than 30 inches, indicating losses from smaller western white pine

and lodgepole pine. Generally, logs are less than 50 feet in length, and they show

higher levels of decay than snags. Decay classes 4 and 5 are relatively common.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 1.3 0.8 0.6 0.4 1.0 1.1 5.2

Snag height (feet)

<20 1.1 0.4 0.2 0.1 - 0.8 2.6

20-50 0.2 0.3 0.2 0.1 0.6 - 1.4

>50 - 0.1 0.2 0.2 0.4 0.3 1.2

Snag decay class

1 0.6 - 0.1 0.1 0.4 0.2 1.4

2 - 0.3 0.2 0.1 0.2 0.3 1.1

3 0.6 0.3 0.1 0.1 0.2 0.2 1.5

4 0.1 0.2 0.1 0.1 0.2 0.4 1.1

5 - - 0.1 - - - 0.1

Figure 27—Number of trees by

diameter class in the red fir-western

white pine-lodgepole pine plant

association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

30

40

50

60

70

80

90

100

110

120
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 143

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 3.5 15.2 3.5 3.0 25.2

Log length (feet)

<20 1.5 5.5 0.8 1.0 8.8

20-50 1.8 7.2 2.0 1.0 12.0

51-100 0.2 2.5 0.7 1.0 4.4

>100 - ----

Log decay class

1 -----

2 - 1.0 0.2 0.5 1.7

3 1.3 5.0 0.7 0.8 7.8

4 1.2 3.7 1.3 0.7 6.9

5 1.0 5.5 1.3 1.0 8.8

Wildlife

Big game forage appears to be moderate to low. Shrubs are absent, and Anderson’s

lupine is the only staple forage species occurring in the forb layer. Hooker’s

bluegrass is a preferred forage species that occurs with low frequency and cover in

the grass layer. Ross’ sedge and western needlegrass are staple forage species for

large game that occur with higher levels of frequency and cover and may provide

a reliable source of forage. Evidence of deer presence was generally observed on

these sites, and pocket gopher presence was usually observed as well.

Range

These are transitional range sites that are used by livestock to access primary range

forage sites such as meadows and other moist habitats. Cattle evidence on these sites

was quite common. The only primary forage species is Hooker’s bluegrass that

occurs with low frequency and cover. Western needlegrass, a secondary range

species, is also present on occasion, and it may provide a part of the diet when

available. Other shrubs, forbs, and grasses occurring on these sites are of low value

for range forage, and it appears range forage potential is low in these late seral stands.

Management Recommendations

Few stands in this association have been harvested, and a clear picture of

regeneration strategies, successional sequences, and stocking levels important in

management have not been developed. Early succession does not appear to

result in high shrub or grass cover in most cases.

These stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable, but the ability of sites to respond to

treatment is uncertain, and the ability to predict results of treatment are not

based on wide experience or research results at this time. Recommendations for

harvesting at present would be to treat stands with caution by keeping harvest

units small and seed supply close. Natural regeneration of existing species

should be encouraged whether sites are planted or not, and extensive time

periods should be expected for regeneration success. Jeffrey pine would not be a

preferred species to plant. Particularly on sites with low site index, management

emphasis directed at maintaining existing wildlife habitat, species richness, and

the landscape level diversity this association provides may be more appropriate.

USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 145

Red Fir-Western White Pine Association

Abies magnifica-Pinus monticola

ABMA-PIMO3

CFRCPW11

Sample size: 35

Distribution

The red fir-western white pine plant association is located at higher elevations

throughout the central and southern Sierra Nevada. It becomes more common

on the landscape south of Kaiser pass in a region where mountain hemlock

begins to diminish in abundance, and it appears to replace mountain hemlock in

the landscape as one continues south. Stands can be somewhat extensive, but in

most cases they appear to be less than 50 acres in size.

Environment

This association is commonly located at elevations above 8,000 feet. This reflects

somewhat higher occurrences in the southern portion of the range where

elevations for similar plant associations in general tend to be higher. The lowest

elevation sampled was on the Eldorado National Forest; whereas, the highest

elevation sampled was on the Sequoia National Forest. Aspects can be varied,

but sites typically face northeast and northwest. Slopes are generally moderate.

Most stands lie on slopes of less than 35 percent, and often they lie on slopes less

than 20 percent. Stands occur generally on ridges and upper to middle slope

positions where microrelief is smooth and uniform. SRI values are moderately

low to low reflecting northerly aspects. Stress indexes are moderately high and

reflect combinations of drier soils but lower SRIs.
146 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Variable Mean Range

Elevation (feet) 8,465 7,140-9,520

Slope (pct.) 25 2-60

Solar radiation index 0.458 0.301-0.542

Bare ground (pct.) 4 0-36

Surface gravel (pct.) 7 0-75

Surface rock (pct.) 8 0-63

Litter (pct.) 80 15-99

Litter depth (inches) 1.2 0.2-3.8

Stress index 0.51 0.33-.61

Aspect: NE, NW.

Range: All.

Position: Ridges, upper and middle slopes.

Range:All.

Vegetation

Stands are moderately dense forests with little understory vegetation. Tree cover

is substantially higher than other western white pine associations. Overstory

layers are characterized by the presence of western white pine in mix with red fir.

In rare stands western white pine may comprise nearly 50 percent of the crown

cover, but generally red fir has the highest cover values. Nevertheless, it is the

relatively higher cover values for western white pine that distinguishes stands

from other associations. Western white pine in general is a dry site indicator, and

it differentiates this association which is a drier habitat than many others.

Understories are quite open. The shrub layer is essentially absent. On a few

sites in the northwestern portion of the study area, huckleberry oak or, on the

eastside, snowbrush constitute a substantial shrub layer, but generally this is not

the case. The sparse forb component is distinguished by the presence of Brewer’s

golden aster and broad seeded rock cress, which are dry site indicators.

Occasionally, western pennyroyal and Sierra wallflower which also indicate

drier sites are present. The grass layer is also very sparse, but it is characterized

by dry site indicators such as bottle brush squirreltail and western needlegrass.

Conifer regeneration is relatively high. The average number of seedlings per

acre was over 900, and usually there are more than 500 seedlings per acre

occurring naturally. Regeneration is dominated by red fir which is almost always

present. Western white pine is often present as well, but this species occurs in far

fewer numbers than red fir. Both red fir and western white pine, however, are

regenerating significantly more often than in other associations.

Plant species diversity is low. Stands often have few species overall, and sites

are commonly dominated by relatively few tree species with cover values that

far outweigh those in the shrub, forb, and grass layers. Thus, abundant species

are few in number and concentrated in the tree species.

The oldest trees in these late seral stands are commonly older than 250 years,

although average stand ages are not substantially different than most other

associations in the upper montane. The oldest tree sampled was a red fir at +585

years, and the oldest western white pine was +359 years.

Stand replacing disturbance events probably occur in this association, but

they do not appear to be frequent or large scale phenomena. The setting of many

stands on cooler north aspects at high elevations, the structure of the stands with

open understories, the presence of relatively large, somewhat fire resistant

individuals, and the natural patchiness of the landscape tend to preclude such fire
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 147

related events over large areas. Stands probably experience patchy burns with

portions of a stand being completely consumed and others left with little damage.

Avalanche can replace stands in this association on middle and lower slopes.

Most of these appear to be somewhat infrequent and occur at scattered locations

across the landscape. Understories, including smaller trees, generally remain

intact. Other disturbance elements such as windthrow, insects, disease, and

lightning also do not appear to affect large areas in these stands. It is likely that

disturbance occurs continuously at various scales, and this results in the creation

of various sized gaps with constantly changing structures through time.

Reproductive strategies such as reasonably constant seed production are

present in most of the tree species on these sites. Since red fir is shade tolerant,

understory trees can occupy sites for long periods of time. Shade intolerant

species such as western white pine are undoubtedly maintained by disturbance

that open stands and provide seed beds.

Few trees in this association appear to originate as a result of a single disturbance

that uniformly covers the site. Stand development appears to be sporadic as

opportunities for regeneration and growth arise in response to disturbance. After

disturbance stands do not seem to go through a prolonged period in a grass/forb or

shrub phase, but in most cases it also appears conifer regeneration is a process that

can occupy a considerable period of time. Once regeneration is established it grows,

self-thins, and matures while other portions of the stand continue to undergo

disturbance. In time, several size and tree classes, including a substantial portion of

larger trees, are represented, and the stand exhibits an irregular structure with many

small relatively even-aged patches. As stands occupy sites for longer periods,

successive disturbance continues to maintain stand structures until an infrequent

stand replacing event occurs and a new stand emerges.

Cover (percent) Mean Range

Total vegetative 75 24-99

Tree 66 20-91

Shrub 2 0-35

Forb 7 0-47

Grass 2 0-13

Moss 0.1 0-2

Stand age (years) 255 100-448

Diversity index

Simpson 0.51 0.16-0.80

Hill numbers

N0 8.9 2.0-19.0

N1 3.17 1.58-8.82

N2 2.36 1.25-6.32

Characteristic Vegetation

Percent cover

Code Common name Constancy Mean Range

I. Overstory trees

PIMO3 Western white pine 100 15 5-56

ABMA Red fir 100 50 10-84

II. Understory trees

ABMA Red fir 97 4 1-25

PIMO3 Western white pine 54 1 1-1

III. Shrubs

None
148 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

IV. Forbs

PESE3 Pine woods lousewort 60 1 1-3

ARPL Broad seeded rock cress 49 1 1-3

CHBR3 Brewer’s golden aster 49 1 1-2

MOOD Mountain pennyroyal 34 2 -18

PHHY Waterleaf phacelia 31 1 1-1

ERPE3 Sierra wallflower 23 1 1-1

PYPI White veined wintergreen 23 1 1-3

V. Grasses and grass-like

SIHY Bottle brush squirreltail 23 2 1-10

STOC1 Western needlegrass 23 1 1-2

CARO1 Ross’ sedge 20 1 1-3

Soils

Most soils are Inceptisols. Entisols are occasionally encountered. Inceptisols are

normally described as Xerumbrepts or Xerochrepts, and most of the Entisols are

Xerorthents. This association differs from other western white pine associations

in containing a higher frequency of soils classified as Inceptisols. Particle size

classes are essentially skeletal indicating the somewhat higher levels of coarse

fragment contents in the subsoils. Parent materials are usually granite; however,

volcanic, metamorphic, or mixed parent materials can be encountered in some

cases. These soils are often formed in place from bedrock, but occasional sites are

formed from materials that have been deposited as alluvium or glacial till.

The majority of soils in this association are moderately deep to deep. Depths

in nearly one-half of the samples exceeded 40 inches, and rarely were depths of

less than 25 inches encountered. Topsoils, on the other hand, are shallow.

Average topsoil depths are some of the lowest in the upper montane, and usually

they are less than 7 inches in this association. Topsoil textures are commonly

sandy loams with occasional gravelly sands and gravelly loams. Typical subsoils

are sandy loams that are often stoney, cobbly, and gravelly. Occasional subsoils

are also gravelly sands, and a few are gravelly loams. Average coarse fragment

contents in subsoils are among the highest in the upper montane. They commonly

exceed 35 percent. Subsoil pH is also substantially more acid in this association

compared to many other upper montane sites.

The AWC of these sites is moderately low to low reflecting coarser and sandier

soil textures. Soils in this association are uniformly distributed between those that

are well drained and those that are excessively drained. Erodibility is often

moderate due to the coarse soil textures. Parent materials are also evenly divided

between those that are unfractured and unrootable and those which are fractured

and rootable. Stress indexes reflect coarser textured soils and lower levels of AWC.

Variable Mean Range

Depth of soil sample (inches) 34 16-40+

Topsoil

Depth (inches) 7 3-15

Coarse frag. (pct.) 22 2-55

pH 5.9 4.5-6.8

Subsoil

Coarse frag. (pct.) 49 10-98

pH 5.5 4.5-6.4

AWC (inches) 2.5 0.4-5.0

Temp (20 inches) (Fahrenheit) 49 39-57

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 149

Productivity

The average Pacific Southwest Region (Region 5) site index is 3 in this association.

However, stands are frequently less than 3, and rarely are they higher. Stand

densities are moderately high. Stand density indexes are usually greater than

400. Stocking levels based on stand density indexes can be nearly 80 percent of

those attained in fully stocked red fir-white fir stands which are some of the

densest in the upper montane. Quadratic mean diameters are among the largest

in the upper montane and reflect the presence of many large trees in these stands.

Tree heights, however, are substantially lower than dense forested stands

elsewhere in the study area. They reflect the presence of both western white pine,

a shorter tree, as well as generally lower site indexes. Cubic foot and board foot

volumes are moderate reflecting the interaction of higher stand density and

shorter trees. Compared to other stands in the western white pine subseries, this

association carries considerably higher stocking levels and yields.

Stand structures in many individual sites appear even-aged; however, overall

stands approach an uneven-age distribution (fig. 28). Compared to a balanced

uneven-age distribution with similar stocking levels, trees in size classes below

18 inches are under-represented, and trees in size classes larger than 30 inches

are over-represented. They contain more trees in both the smaller and larger size

classes than would be appropriate with an even-age distribution.

Variable Mean Range

Region 5 site index 3 1-5

Forest survey site class 4 2-6

Stand density index 411 135-723

Quadratic mean diameter 24.8 11.0-35.8

Softwood volume (mcf/ac) 10.3 2.8-25.7

Softwood volume (mbf/ac) 69.0 17.5-185.7

Softwood basal area (sq ft/ac) 316 80-600

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Figure 28—Number of trees by

diameter class in the red fir-western

white pine plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

30

40

50

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 76 1 3 - 20 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -
150 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Coarse Woody Debris

Snag numbers are moderate to high, and they are distributed among all size

classes. Snags in size classes less than 11 inches are abundant reflecting selfthinning within small patches of sapling and pole size trees. Mortality is

distributed randomly among the species present. Snag heights and decay classes

are also distributed among all classes, but snags in this association are typically

less than 50 feet in height, and they occur in decay classes 1 and 2. Logs are also

distributed among all size classes. They are generally shorter than 50 feet in

length, and they show higher levels of decay than snags. Decay classes between 3

and 5 predominate.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 8.5 1.1 1.6 0.6 0.5 0.8 13.1

Snag height (feet)

<20 7.1 - - 0.3 0.3 - 7.7

20-50 1.4 0.5 - 0.1 0.1 0.5 2.6

>50 - 0.6 1.6 0.2 0.1 0.3 2.8

Snag decay class

1 7.1 - - 0.1 - - 7.7

2 - 1.1 1.6 0.1 0.1 0.3 3.2

3 1.4 - - 0.2 0.2 0.5 2.3

4 - - - 0.1 0.1 - 0.2

5 - - - 0.1 0.1 - 0.2

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 2.5 7.5 3.5 2.0 15.5

Log length (feet)

<20 1.5 5.0 2.0 1.5 10.0

20-50 0.5 1.0 1.0 - 2.5

51-100 0.5 1.5 0.5 - 2.5

>100 - - - 0.5 0.5

Log decay class

1 -----

2 - - - 0.5 0.5

3 1.5 3.0 - - 4.5

4 1.0 4.0 3.0 1.5 9.5

5 - 0.5 0.5 - 1.0
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 151

Wildlife

These stands may offer hiding and thermal cover to large game, but forage

possibilities appear transitory. Of the species occurring in this type few are

preferred wildlife forage. Waterleaf phacelia in the forb component and bottle

brush squirreltail, western needlegrass, and Ross’ sedge in the grass component

are staple parts of the large game diet. Constancy and cover values for these

species, however, are relatively low. On the other hand, evidence of deer and

pocket gopher presence was common in these stands.

Range

These are transitional range sites that are used by livestock to access primary

range such as meadows and other moist habitats. Bottle brush squirreltail and

western needlegrass are secondary forage species, but constancy and cover

values are low. No other commonly occurring species in this association are of

primary or secondary range value. Range forage potential is low in these late

seral stands although cattle presence in this association was quite common.

Management Recommendations

Relatively few stands in this association have been harvested for long enough

periods to develop a clear picture of appropriate silvicultural systems, cutting

methods, regeneration techniques, successional sequences, and stocking controls

important in management. In a few cases clearcutting under the even-age

silvicultural system has been used. Practices on these sites included planting

Jeffrey pine. In general, Jeffrey pine plantings have not been successful.

Regeneration strategies for planting red fir or western white pine have not been

developed for this association. Natural regeneration from both red fir and western

white pine seems to be abundant as long as stand sizes are kept small. Early

succession does not seem to result in high shrub or grass cover in most cases.

These stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable, but the ability of sites to respond to

treatment is uncertain, and the ability to predict results of treatment are not

based on wide experience or research results at this time. Recommendations for

harvesting on high sites at present would be to treat such stands with caution by

keeping stand size small and adjacent seed supply close. Topsoils can be shallow

on many sites, and site preparation should be done with care. Jeffrey pine would

not be a preferred species to plant. Natural regeneration of existing species

should be encouraged whether sites are planted or not. On poorer sites

management emphasis may be more appropriately directed at maintaining

existing wildlife habitat and the landscape level diversity this association

provides.

USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 153

White Fir-Sugar Pine-Red Fir Association

Abies concolor-Pinus lambertiana-Abies magnifica

ABCO-PILA-ABMA

CFWCPR11

Sample size: 33

Distribution

The white fir-sugar pine-red fir plant association is widespread at lower

elevations in the upper montane. Stands are located only on westside forests, and

they define the transition into upper montane forests from white fir-sugar pine

dominated communities that lie at lower elevations. Latitudes and longitudes

span the range of the study area. Stands can be quite extensive such as those near

Crane Flat in Yosemite National Park, but most are smaller and probably cover

less than 50 acres.

Environment

This association occurs at the lowest elevations in the upper montane, and it often

serves to identify the transition into the upper montane from lower elevations. It

typically occurs below 7,500 feet. The lowest elevation observed was at 5,860 feet

on the Eldorado National Forest, and the highest was on the Sequoia National

Forest at 7,880 feet. Aspects and slopes are varied, but solar radiation levels are

among the lowest in the upper montane. Typically, sites are located on middle

and lower slope positions, reflecting a tendency for stands to be located in cold air

drainages at lower elevations. Microrelief is commonly undulating or hummocky.

This association has significantly less bare ground and surface gravel than most

other sites, and litter depths are among the highest of the upper montane forests,

reflecting higher levels of tree cover and debris on the forest floor which is

characteristic of these stands. Stress indexes are not substantially different than

most other sites, and they indicate moderate levels of moisture stress.
154 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 6,881 5,860-7,880

Slope (pct.) 27 3-60

Solar radiation index 0.477 0.326-0.582

Bare ground (pct.) 0.8 0-3

Surface gravel (pct.) 0.9 0-10

Surface rock (pct.) 3 0-20

Litter (pct.) 95 80-99

Litter depth (inches) 1.9 0.2-5.5

Stress index 0.51 0.35-0.62

Aspect: All.

Range: All.

Position: Middle and lower slopes.

Range: All.

Vegetation

Stands are dense multilayered forests with a moderate cover of understory

shrubs and forbs. Total vegetative cover is high in conjunction with tree cover,

which is considerably higher than most associated stands. These stands are often

adjacent to and interspersed with the red fir-white fir and redfir-white fir-Jeffrey

pine associations on mesic sites. The overstory is characterized by red fir in mix

with several other conifer species. White and red fir are generally dominant both

in frequency of occurrence and cover. Sugar pine is a characteristic species,

although it typically occurs as widely scattered predominants, resulting in lower

constancy. Jeffrey pine and incense cedar are occasionally present as well, and

incense cedar can be used as an indicator of the association when present. Black

oak is a seldom occurring but useful hardwood indicator of the association as

well. Often sugar pine, incense cedar, or black oak are all present, but it is the

occurrence of sugar pine or incense cedar in mixture with red fir that indicates

the association.

Understories are a mix of species indicating variation in site conditions from

dry to mesic. Understory shrubs commonly occupy between 5 and 25 percent

cover as scattered individuals and patches. This layer is typically characterized by

relatively high constancy and cover of Sierra chinquapin, which is a dry site

indicator. Individual sites can be dominated by Sierra chinquapin, or on occasion,

pinemat or greenleaf manzanita. Although these species occur less often, they are

also indicators of drier conditions when present. The occasional appearance of

creeping snowberry and Sierra gooseberry confirm mesic conditions when present.

White-veined wintergreen, Kellogg’s bedstraw, white flowered hawkweed, and

western bracken fern are all forb species that are usually present in moist habitats.

The grass cover is essentially absent, but the rare occurrences of Bolander’s

bluegrass or blue wildrye are useful in distinguishing moderate conditions.

An important element in the understory of these stands is the presence of

several shrub and forb species that occur at low constancy and can dominate sites

after disturbance. In the shrub layer these are species such as mountain whitethorn,

bittercherry, and Sierra chinquapin. In the forb layer western bracken fern, Drew’s

silky lupine, Anderson’s lupine, and broad leaved lupine are further examples.

Conifer regeneration is moderate. The average number of seedlings is 448

per acre, and stands commonly contain more than 100 per acre. The majority of
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 155

sites have white and red fir regeneration occurring at relatively high levels and

in equal abundance. Sugar pine and incense cedar are occasionally present but in

numbers substantially below those of white and red fir. Jeffrey pine is a rare

occurrence in the regeneration layer, reflecting lower presence in the overstory

and the effects of high cover on this shade intolerant species. White fir, sugar

pine, and incense cedar are regenerating significantly more often than in other

plant associations.

Plant species diversity is moderate. When compared to other associations in

the upper montane, the total number of species is mid-range. Diversity in these

stands resides in the overstory tree species that far outweigh cover values of the

shrubs, forb, and grass layers. Abundant species are moderate in number, and

they are concentrated in the trees species.

The oldest trees in these stands are often older than 250 years, but the

average age of stands is significantly younger than most other associations in

these forests. The oldest tree sampled was an incense cedar at +530 years Other

older individuals in these stands were a white fir at +348 years, a redfir at +252

years, and a sugar pine at +248 years. These ages are typical of upper montane

forests in general. The reason for the relatively younger average stand ages is

unclear. Higher numbers of younger trees in the overstory obviously contributes

to this, but the origin of these younger trees is somewhat obscure at present. It is

possible that historically higher fire frequency associated with lower elevations

maintained a substantial number of young trees in these stands.

Since stands lie adjacent to lower montane forests with high fire frequency and

intense burns, stand replacing fires probably occur in this association more

frequently than many others in the upper montane. However, the location of many

stands on lower and middle slope positions or along drainage bottoms, and the

structure of the stands with relatively large, somewhat fire resistant individuals

tend to preclude large scale loss of all individuals from most fires. Stands probably

experience both small scale patchy burns with occasional large scale stand

replacing fires. Both patterns can be observed in existing stand structures.

Other disturbance elements such as windthrow and avalanche are not

widespread features of these stands. Insects, disease, and lightning are more

common, but mortality from these factors often occurs in localized situations or

in select species. Disturbance occurs continuously on various scales in these

stands. This results in the creation of various sized gaps with constantly changing

structures through time.

Reproductive strategies such as reasonably constant seed production is present

in most of the tree species in these stands. Other reproductive strategies, such as

sprouting or delayed germination of seed until scarified by fire, are also present in

many of the shrub species on these sites. Sierra chinquapin is a sprouting species

for example. Shade intolerant species such as Jeffrey pine are undoubtedly

maintained by disturbances that open stands and provide seed beds.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. After disturbance, the most likely

successional sequence involves early dominance by shrubs, forbs, and grass.

These early communities can be quite persistent, and replacement by trees can be

a prolonged process. Once regeneration is established, however, it grows, selfthins, and matures while other portions of the stand continue to undergo

disturbance. In time, a patchy distribution of trees emerges with several size and

tree classes represented, including a substantial portion of larger trees. The stand

exhibits an irregular structure with small relatively even-aged patches distributed

throughout. As stands occupy sites for longer periods, successive disturbance

continues to develop and maintain these structures until an infrequent stand

replacing event occurs and a new stand emerges.
156 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Cover (percent) Mean Range

Total vegetative 85 62-98

Tree 76 37-93

Shrub 12 0-66

Forb 7 0-41

Grass 0.5 0-2

Moss 0.3 0-3

Stand age (years) 187 76-379

Diversity index

Simpson 0.39 0.16-0.73

Hill numbers

N0 10.7 3.0-21.0

N1 4.76 1.67-8.97

N2 3.14 1.37-6.23

Characteristic Vegetation

Percent cover

Code Common name Constancy Mean Range

I. Overstory trees

ABCO White fir 97 33 3-81

ABMA Red fir 97 32 1-81

PILA Sugar pine 61 13 1-34

PIJE Jeffrey pine 21 19 7-41

LIDE3 Incense cedar 15 13 7-21

II. Understory trees

ABMA Red fir 85 1 1-8

ABCO White fir 82 1 1-6

PILA Sugar pine 45 1 1-1

LIDE3 Incense cedar 30 1 1-1

III. Shrubs

CASE3 Sierra chinquapin 67 10 1-65

SYAC Creeping snowberry 27 5 1-19

RIRO Sierra gooseberry 21 1 1-4

IV. Forbs

PYPI White veined wintergreen 67 1 1-2

KEGA Kellogg’s bedstraw 42 1 1-4

PTAQ Western bracken fern 42 6 1-35

HIAL White flowered hawkweed 36 1 1-4

PESE3 Pine woods lousewort 36 1 1-1

COMA4 Spotted coral root 30 1 1-1

APMEF Western dogbane 27 1 1-1

CHBR3 Brewer’s golden aster 27 1 1-2

PHHY Waterleaf phacelia 24 1 1-1

V. Grasses and grass-like

None
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 157

Soils

Soils are commonly Inceptisols. These soils usually lie in the Xerumbrept great

group, but Xerochrepts can be encountered on occasion. Entisols and Alfisols are

of minor occurrence, and most are Orthents, Psamments, and Xeralfs. Particle

size classes are distributed almost evenly between skeletal and loamy, indicative

of moderate levels of larger sized coarse fragments in the profile. Typical soils

are derived from granitic parent materials and rarely from volcanic,

metamorphic, or sedimentary substrates. Most of these soils are formed in place

from bedrock. Glacial till and colluvial deposits occur on infrequent sites.

Soils are deep. More than 50 percent of the sample sites had soils that

exceeded 40 inches. Rare sites had depths less than 30 inches. Soil textures in the

topsoil are characteristically sandy loams or loams with rare sands and sandy

clay loams also present. Topsoils, however, contain a significantly higher

proportion of cobbles and gravels in the horizon. Subsoil textures are similar to

topsoils, but they contain higher proportions of sands and fewer loams, and they

also have higher proportions of cobbles and gravels.

The AWC of these sites ranges considerably; average values, however, are

not substantially different from most other sites. They can be considered to be

moderate and reflect the variation in soil textures and coarse fragment content of

individual sites. Bedrock below the soil profile is typically fractured and rootable

providing additional sources of water, and most sites are well drained. Stands

with excessive drainage often lie on steep slopes with sandy textures. Erodibility

ranges from moderate to high in response to soil textures or slope steepness.

 Variable Mean Range

Depth of soil sample (inches) 37 26-40+

Topsoil

Depth (inches) 10 3-24

Coarse fragments (pct.) 23 5-75

pH 6.2 5.1-7.2

Subsoil

Coarse fragments (pct.) 38 5-80

pH 6.0 5.3-7.0

AWC (inches) 3.4 0.8-6.6

Temp (20 inches) (Fahrenheit) 49 42-59

Productivity

Site indexes are very high. They are substantially higher than most others, and

they are comparable to the red fir-white fir association that consistently has some

of the highest site indexes in the upper montane. Commonly, Pacific Southwest

Region (Region 5) site indexes are 1 or better. Rare stands had site indexes lower

than 2. Stand densities are also high. Stand density indexes frequently exceed

400, and average stocking levels based on stand density indexes are nearly 90

percent of those attained in a fully stocked red fir-white fir stand. Trees are also

considerably taller than those in most associated stands reflecting better site

indexes. Heights of the tallest trees measured in this association, for example,

were 212 feet for red fir, 203 feet for white fir, and 174 feet for the tallest sugar

pine. Cubic and board foot yields are among the highest in the upper montane,

and they compare favorably to values attained in the most productive

associations in these forests.

Most stands are irregular in structure, and distributions tend to approach

those of an uneven-aged stand (fig. 29). Compared to uneven-aged stands with

similar stocking and balanced diameter distributions, trees in size classes
158 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

smaller than 18 inches are higher in number than expected, although they also

carry more trees in size classes larger than 35 inches. Compared to an evenaged distribution with similar stocking levels, both smaller and larger size

classes are over-represented. Stands closely parallel the distributions of trees in

the red fir association.

Variable Mean Range

Region 5 site index 1 0-3

Forest survey site class 2 1-4

Stand density index 458 99-824

Quadratic mean diameter 24.4 11.3-39.8

Softwood volume (mcf/ac) 13.5 1.1-24.3

Softwood volume (mbf/ac) 97.3 20.1-175.8

Softwood basal area (sq ft/ac) 347 88-587

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

30

40

50

60

70

80 Figure 29—Number of trees by

diameter class in the white fir-sugar

pine-red fir plant association.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 41 41 - 6 - -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - 9 3 - - -

Coarse Woody Debris

Snag numbers are high. Snags in the 6 to 11 inch size class are among the highest

in the upper montane, and snags in the 25 to 30 inch size class and those larger

than 40 inches in diameter occur in substantially higher numbers than most other

stands. Mortality in smaller size classes appears to be related to thinning of

suppressed individuals, and mortality in the larger size classes appears to be

related to senescence of large individuals. Mortality is uniformly distributed

among species. Most snags are less than 50 feet tall indicating a tendency of large

standing snags to break off over time. They typically lie in decay classes between

1 and 3. Logs commonly are less than 30 inches in large end diameter, but larger

sizes are well represented in some stands. The majority of logs are shorter than

50 feet in length, and they evidence higher levels of decay than snags. Decay

classes 3 through 5 are most common.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 159

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 16.0 1.6 1.6 1.1 1.0 2.3 23.6

Snag height (feet)

<20 11.0 0.7 - - 0.2 0.3 12.2

20-50 2.5 0.1 0.8 - 0.3 1.0 4.7

>50 2.5 0.8 0.8 1.1 0.5 1.0 6.7

Snag decay class

1 0.8 0.1 - 0.7 - 0.1 1.7

2 6.7 0.7 0.8 0.4 0.5 0.8 9.9

3 2.5 0.3 0.8 - 0.3 1.2 5.1

4 6.0 0.5 - - 0.2 - 6.7

5 - - - - - 0.2 0.2

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 5.3 6.5 3.8 2.5 18.1

Log length (feet)

<20 3.9 3.3 2.5 0.2 9.9

20-50 1.0 2.5 0.5 0.8 4.7

51-100 0.4 0.7 0.8 1.2 3.0

>100 - - - 0.5 0.5

Log decay class

1 0.3 0.2 - - 0.5

2 0.7 1.9 0.7 0.5 3.8

3 2.3 1.1 1.3 1.0 5.7

4 1.7 2.4 1.1 0.7 5.9

5 0.3 0.9 0.7 0.3 2.2

Wildlife

These stands may offer some hiding and thermal cover to large game, but forage

possibilities appear transitory. Stands provide few staples for the large game diet.

Western bracken fern and waterleaf phacelia are staples, but constancy and cover

values for phacelia in particular are low. Grass is generally a major constituent of

large game diets, but this taxon is essentially missing from the association.

Evidence of deer and pocket gopher presence, however, was common.

Range

These stands are transitional range forage sites that are used by livestock to

access primary forage sites such as meadows and other moist habitats, although

cattle were generally present in these stands. Grass is generally a major

constituent of the range diet, but this group is missing from the association.

Other shrubs and forbs that are present are low value forage. It appears forage

production on these sites is low.
160 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Management Recommendations

Many stands in this plant association have been harvested in the upper montane.

Early harvests were directed at improvement cuttings, but in recent years a

variety of harvests designed to create essentially even-aged stands has been

practiced. Little reliance has been placed on obtaining natural regeneration in

these cuttings. Many sites have been planted to Jeffrey pine and sugar pine.

Occasionally white fir has been planted as well. Results in most cases are good

with many well stocked and growing plantations. Recent failures with sugar

pine planting can be attributed to a rise in the presence of white pine blister rust

in the region, with a corresponding increase in sugar pine mortality. White fir

plantings have also not done as well in some cases. This seems to result from

problems with early survival rather than competition at a later stage of

development. The low levels of natural Jeffrey pine regeneration in the dense

stands typical of this association are probably in direct relationship to high stand

densities. This species seems to do well once stand density is lowered.

These sites also produce high levels of shrub and forb cover when disturbed.

Except for Sierra chinquapin, the original cover values for competing shrub and

forb species are low; however, through resprouting and germination of stored

seed, early succession on these sites can be dominated by persistent shrub and

forb competition. Squaw currant, bitter cherry, and Sierra chinquapin in the

south, and mountain whitethorn elsewhere can quickly dominate a specific site.

Western bracken fern, Anderson’s lupine, Drew’s silky lupine and broad leaved

lupine in the forb component can do the same.

These stands have tremendous productive capacity and flexibility for stand

management. Stand structures are variable, and options for silvicultural systems

and cutting methods can vary to take advantage of the shade tolerance and high

stand densities attainable in these stands. Natural regeneration can be a viable

option. Stand openings should be kept small and seed source near. On northfacing slopes small clearcuts can be utilized, but on south aspects shelterwood

cutting or a silvicultural system that maintains constant tree cover is

recommended. High levels of shrub, forb, and grass competition should be

anticipated when openings are created. In particular sites at lower elevations on

south aspects can become occupied with species that offer serious competition to

new seedlings. Most reforestation prescriptions in this type should plan for

vigorous vegetation control early in the life of any plantation.

These sites also have the potential to contribute to wildlife values. In their

present condition they are an important source of snags, and through

management, they can continue to provide snags for a period of time after

harvest. Many of the species expected to offer competition to conifer seedlings

are also preferred or secondary large game food sources. Mountain whitethorn

and bitter cherry are preferred forage. Careful vegetation management early in

the life of plantations can probably maintain wildlife forage and not seriously

impact reforestation efforts.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 161

Jeffery Pine/Huckleberry Oak Association

Pinus Jeffreyii/Quercus vaccinifolia

PIJE/QUVA

CPJCPJ12

Sample size: 32

Distribution

The Jeffrey pine/huckleberry oak plant association is located in the northwestern

portion of the study area. In general, huckleberry oak does not extend south of

latitude 37° in the Sierra Nevada, and this association characteristically occurs

north of latitude 37°30’. The most southerly stand sampled was on the Sierra

National Forest near Chilkoot Lake. As one travels north these communities

become more common. This is predominantly a westside association. Longitudes

were generally greater than 119°30’, and few stands were sampled on the eastside.

Stands are often quite extensive and can cover areas of 100 acres or more.

Environment

This is a lower elevation plant association. This reflects distributions in the northern

portion of the study area in which similar associations commonly appear at lower

elevations than further south, but it also is a typically lower elevation association

even in the north. Stands often mark the transition into the upper montane from

lower elevation forests. Slopes are varied, but normally they are steeper than 20

percent, and a few exceed 40 percent. Stands generally occupy ridges and upper

and middle one-third slope positions. They commonly face southeast to southwest

where SRI levels are substantially higher than most other sites. Typical stands have

more surface gravel than most other sites, and site microrelief is frequently

hummocky and broken. These are dry sites, and this is reflected in stress indexes

which are considerably higher than most other associations.
162 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 7,320 6,300-8,320

Slope (pct.) 27 4-58

Solar radiation index 0.517 0.392-0.594

Bare ground (pct.) 3 0-15

Surface gravel (pct.) 4 0-20

Surface rock (pct.) 13 1-46

Litter (pct.) 80 32-96

Litter depth (inches) 1.2 0.2-2.4

Stress index 0.56 0.45-0.64

Aspect: SE, SW.

Range: All.

Position: Ridges and upper slopes.

Range: All.

Vegetation

Stands are open woodlands with a characteristically heavy cover of huckleberry

oak and pinemat manzanita. Total vegetative cover is high due to the substantial

cover of shrubs, but tree cover is significantly lower than most other associations,

and trees tend to occur as scattered clumps and individuals.

The overstory is characterized by the presence of Jeffrey pine which is a dry

site indicator. Both white and red fir are typical associates although western

white pine, western juniper, and lodgepole pine occur as rare, scattered

individuals. Occasional stands are dominated by red or white fir, and Jeffrey

pine can be a scattered or missing component in these cases, but the understory is

dominated by huckleberry oak which indicates the association. The presence of

white fir and Jeffrey pine are generally indicative of the lower elevations of this

association. These stands often lie adjacent to white fir-sugar pine-red fir, red firwhite fir, and red fir-white fir-Jeffrey pine plant associations as conditions

become mesic at lower elevations.

The understory is predominantly a mix of huckleberry oak and pinemat

manzanita with an occasional mountain whitethorn in the shrub layer. Both

huckleberry oak and pinemat manzanita are dry site indicators, and mountain

whitethorn inhabits moderate to dry sites. Broad seeded rock cress, naked

stemmed eriogonum, Coville’s gayophytum, and mountain pennyroyal in the

forb layer all indicate the drier conditions in this association. Bottle brush

squirreltail and western needlegrass in the grass component are also dry site

indicators.

Conifer regeneration is moderate to low. The average number of seedlings

per acre is 376, but distributions are skewed, and the median value is only 85 per

acre. Over 50 percent of the samples had less than 100 seedlings per acre, and

only on occasion did sites carry more than 500 per acre. White and red fir

dominate the regeneration layer. Interestingly, Jeffrey pine is present

infrequently, and it occurs in very low numbers, but both white fir and Jeffrey

pine are regenerating significantly more often than in other associations.

Plant species diversity is moderate to high for these upper montane forests,

and sites are considerably more diverse than many associated stands. They have

moderate to high numbers of species overall. The number of tree species present

is higher than on many other sites, and tree cover is relatively low because of the

wide spacing of individuals. Several species are present in the shrub layer, and

although shrubs can dominate the understory, several forb and grass species also
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 163

generally occupy sites. Overall, the number of abundant species is somewhat

higher than in many other stands, and these species are somewhat uniformly

distributed between trees and shrubs.

The oldest trees in these stands were typically older than 250 years. Although

they are not substantially older than other stands in these forests on average,

Jeffrey pine, as a species, can attain a considerable age. Often it is older than most

other species when it occurs in combination in these late seral stands, and the

older ages of many stands appears to lie in the greater ages attained by Jeffrey

pine. The oldest tree measured in this association was a Jeffrey pine at +631

years. By comparison, the oldest white fir was +298 years, and the oldest red fir

was estimated at +246 years.

Stand replacing disturbance events probably occur in this association at

somewhat higher frequencies than others in the upper montane. Shrubby sites

on somewhat steeper slopes and drier, southerly aspects with irregular tree

distributions would indicate a different fire regime than many others in these

forests. High shrub cover and south aspects favor larger more intense fires;

however, shrub cover is seldom continuous, and the structure of most stands

with stocking concentrated in widely spaced, relatively large, somewhat fire

resistant individuals would tend to ensure some level of tree survival after a fire.

Burns are probably patchy, and portions of the stand are left with little damage

while others burn intensely. Isolated large trees probably escape damage in most

cases. Other disturbance elements such as windthrow and avalanche are not

common features of these stands. Insects, disease, and lightning are more

common, but they generally occur in localized situations or on select species and

do not cover large areas.

Reproductive strategies such as consistent seed production, germination on

mineral soil, sprouting, widespread seed dispersal, or delayed germination until

seeds are scarified by fire is present in species on these sites. Jeffrey pine is a

consistent seed producer that does well on mineral seedbeds. Huckleberry oak

and mountain whitethorn are sprouting species, and pinemat manzanita sprouts

from stems, but it does not crown sprout. In most cases the species composition

of future stands is largely determined by species currently on these sites.

Disturbance creates opportunities for regeneration, but many microhabitats

are unsuitable for establishment, and regeneration is often a prolonged process

on these sites. Disturbance also provides opportunities for surviving individuals

to increase growth. Scattered patches of trees probably escape many disturbances

and proceed through a period of crown closure and self thinning. Isolated trees

and small patches that escape repeated disturbance eventually mature into

larger members of the stand. In time, stands develop an irregular structure

reflecting numerous disturbances and containing large trees that are the

survivors of multiple disturbances.

Cover (percent) Mean Range

Total vegetative 83 38-99

Tree 36 8-67

Shrub 55 13-90

Forb 10 0-80

Grass 1 0-8

Moss 0.4 0-3

Stand age (years) 243 112-496

Diversity index

Simpson 0.28 0.12-0.50
164 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Hill numbers

N0 13.0 7.0-24.0

N1 5.50 2.71-11.09

N2 4.25 2.00-8.65

Characteristic Vegetation

Percent cover

Code Common name Constancy Mean Range

I. Overstory trees

PIJE Jeffrey pine 88 15 1-52

ABCO White fir 69 16 1-45

ABMA Red fir 59 19 4-41

II. Understory trees

ABCO White fir 78 2 1-8

ABMA Red fir 75 1 1-4

PIJE Jeffrey pine 38 1 1-1

III. Shrubs

QUVA Huckleberry oak 100 30 1-81

ARNE2 Pinemat manzanita 62 29 1-89

CECO2 Mountain whitethorn 38 4 1-17

PREM Bitter cherry 31 1 1-3

SYAC Creeping snowberry 28 3 1-10

IV. Forbs

PESE3 Pine woods lousewort 44 2 1-10

ARPL Broad seeded rockcress 41 1 1-3

ERNUD Naked stemmed eriogonum 38 1 1-80

GAER Coville’s gayophytum 38 4 1-30

CHBR3 Brewer’s golden aster 34 1 1-1

APMEF Western dogbane 31 1 1-1

ERBR2 Brewer’s daisy 31 2 1-40

ALOB Red Sierra onion 28 1 1-2

PYPI White veined wintergreen 28 1 1-1

MOOD Mountain pennyroyal 25 2 1-20

SEAR Woody butterweed 25 1 1-30

V. Grasses and grass-like

SIHY Bottle brush squirrletail 31 1 1-3

STOC1 Western needlegrass 25 1 1-3

Soils

Soils in this association are predominantly Inceptisols with occasional Entisols.

Alfisols are encountered in rare cases. The Inceptisols lie typically in the

Xerumbrept great group, but Xerochrepts are sometimes encountered as well.

Entisols are evenly divided between Orthents and Psamments. Particle size

classes are commonly skeletal indicating the higher levels of coarse fragments

in the profile. These soils are generally derived from granitic parent material,

Cover (percent) Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 165

and although they are normally formed in place from bedrock, they are

occasionally formed from glacial tills and glacial outwash materials. Glacial

deposits form a significant component in these stands when compared to

other associations.

Soils are moderately deep to deep. Usually they exceed 35 inches in depth,

and some were greater than 40 inches. Depths of less than 25 inches were

uncommon.

Compared to depths in dense forested stands in the upper montane, these

soils are shallow. Soil textures in both the topsoil and subsoil are often sandy

loams with occasional sands. Loams are seldom encountered. Topsoil sands are

typically gravelly or cobbly, and overall there are significantly higher proportions

of cobbly textures in the topsoil, and stoney textures in the subsoil. Topsoils have

a considerably higher portion of sites with coarse fragments between 35 and 65

percent compared to most other sites. Subsoils have among the highest average

coarse fragment contents of all the upper montane plant associations. Sites

typically have more than 35 percent coarse fragments in these lower horizons.

These features are reflective of sites that lie on glacial deposits.

The AWC of these sites is lower than most other plant associations in the

study area. Stress indexes are high due to both lower AWC and locations on

upper slope positions. Soils frequently occur on substrates that are fractured and

rootable and able to supply additional sources of moisture to stands. These sites

also differ substantially from many others in that drainage is typically excessive

and reflects the coarse textures present in the soil. Erodibility is moderate as a

result of these same soil textures.

 Variable Mean Range

Depth of soil sample (inches) 32 13-40+

Topsoil

Depth (inches) 9 2-38

Coarse fragments (pct.) 25 3-65

pH 5.7 5.0-6.5

Subsoil

Coarse fragments (pct.) 46 5-85

pH 5.9 5.0-6.9

AWC (inches) 2.4 0.6-5.4

Temp (20 inches) (Fahrenheit) 52 44-66

Productivity

Pacific Southwest Region (Region 5) site indexes tend to be lower than dense

well-stocked stands in the study area. In general, site indexes were evenly

distributed between higher and lower sites; however, these stands have a high

proportion of sites with indexes of 4 and 5. Stand density is also low. Average

stand density indexes are typically lower than 300, and stocking levels based on

average stand density indexes are less than 45 percent of those reached in the red

fir-white fir association, which is one of the densest in the upper montane.

Stocking resides in the larger individuals of the stand. The average quadratic

mean diameter is similar to those in the red fir-white fir association, which is

stocked with many large trees per acre. Tree heights are significantly lower than

associations with higher site index. The tallest tree measured was a Jeffrey pine

at 172 feet. The tallest white fir encountered was 156 feet, and the tallest red fir

was 141 feet. The majority of heights on dominant trees in this association were

less than 150 feet. The combination of lower site indexes, lower stand densities,
166 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

and shorter tree heights result in less basal area stocking and lower cubic foot

and board foot yields from these stands.

Structures in individual stands are irregular. Considered as a whole,

however, the association has the appearance of an uneven-age structure (fig. 30).

Stands tend to be open with few total trees per acre. They commonly carry fewer

than 100 trees per acre. Compared to an uneven-aged structure with a balanced

diameter distribution and similar stocking levels, these stands have too few trees

in size classes smaller than 18 inches and an excess of trees larger than 30 inches.

When compared to even-aged distributions, they have an excess of trees in both

smaller and larger size classes.

Variable Mean Range

Region 5 site index 3 2-5

Forest survey site class 4 3-6

Stand density index 224 50-592

Quadratic mean diameter 23.0 9.7-39.7

Softwood volume (mcf/ac) 5.2 1.2-14.2

Softwood volume (mbf/ac) 36.9 8.9-98.8

Softwood basal area (sq ft/ac) 155 40-320

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

30

40

50

60

70

80

90

Figure 30—Number of trees by

diameter class in the Jeffrey pine/

huckleberry oak plant association.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 32 36 2 28 1 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent 1 - - - - -

Coarse Woody Debris

Snag density is low reflecting the open stand conditions that are common. Most

snags were larger than 25 inches DBH. Overall, mortality was distributed more

heavily in red and white fir on these sites. This was particularly so in the smaller

size classes. Snags taller than 50 feet are well represented and reflect the presence
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 167

of both larger diameter snags and the presence of Jeffrey pine, which decays

slowly and can remain standing for long periods. Snags generally lie in decay

classes 1 to 3. Logs were typically less than 30 inches in diameter. They were

predominantly less than 50 feet in length and demonstrate higher levels of decay

than snags. Decay classes of the samples were characteristically between 3 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0.2 0.1 0.5 0.7 0.6 2.1

Snag height (feet)

<20 - 0.1 - 0.2 0.2 - 0.5

20-50 - 0.1 0.1 0.2 0.2 - 0.6

>50 - - - 0.1 0.3 0.6 1.0

Snag decay class

1 - - 0.1 0.2 0.1 - 0.4

2 - - - - 0.3 - 0.3

3 - - - 0.2 0.3 0.6 1.1

4 - 0.2 - 0.1 - - 0.3

5 - - - - - --

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 2.4 4.0 1.4 1.0 8.8

Log length (feet)

<20 2.0 3.2 0.8 - 6.0

20-50 0.4 0.8 0.6 0.6 2.4

51-100 -----

>100 - - - 0.4 0.4

Log decay class

1 -----

2 0.6 0.2 0.2 0.2 1.2

3 1.0 2.4 - 0.2 3.6

4 0.4 0.8 0.6 0.6 2.4

5 0.4 0.6 0.6 - 1.6

Logs per acre 2.4 4.0 1.4 1.0 8.8

Wildlife

Forage values appear to be moderate since several species are present that can

provide large game forage. Mountain whitethorn and bittercherry are preferred

species, and naked stemmed eriogonum and Brewer’s daisy are staples in the

large game diet. These species occur with reasonable constancy and cover values

and would appear to contribute to forage values on these sites. Bottle brush

squirreltail and western needlegrass are also staples, but they occur with lower

constancy and cover. Deer sign was often observed in these stands, but

observations were lower than on many other sites. Gophers were common.
168 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Range

Range potential in this association appears to be transitory as livestock move to

nearby primary range sites such as meadows and other moist habitats.

Nevertheless, cattle presence was observed in a majority of the stands. Bottle

brush squirreltail and western needlegrass are secondary forage species, but

frequency of occurrence and cover values are low. Other shrub, forb, and grass

species occurring on these sites are of low value for range forage, and it would

appear that contributions to range forage from this association are also low.

Management Recommendations

This plant association has not been extensively harvested. The harvesting that

has occurred has generally been a form of partial cutting with no clearly defined

silvicultural system other than salvage. Management in many cases has relied on

established stocking to regenerate sites, but most late seral stands have low

levels of natural regeneration, and disturbance due to harvesting has not

increased conifer stocking. Competition from existing shrubs appears to be

severe, and trees can be under stress for long periods. Mortality rates in seedlings

is probably high, and seed flow into the site is low due to the low density of

mature trees. Long time periods can be expected to establish stocking through

natural regeneration. Techniques for reforestation strategies involving planting

have not been developed on these sites at this time, and success rates from such

attempts can be expected to be low with current experience.

These stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable, but species composition, site index,

or stand density is often limiting, and the ability to predict results of treatment is

not based on wide experience at this time. The open nature of these stands

indicates that regeneration and establishment is a lengthy and variable process

under most conditions. Recommendations for harvesting at the present time

would be to treat stands in this type with caution and expect that results can be

uncertain. Appropriate management should be directed at maintaining the

landscape level diversity such plant communities provide through treatments

which maintain the species composition experienced in these stands.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 169

Jeffrey Pine/Greenleaf Manzanita-Snowbrush Association

Pinus jeffreyii/Arctostaphylos patula-Ceanothus velutinus

PIJE/ARPA

CEVE3 CPJCPJ13

Sample size: 32

Distribution

The Jeffrey pine/greenleaf manzanita-snowbrush plant association is widespread

at middle to upper elevations in the Sierra Nevada. It was sampled on most

National Forests and Parks in the study area, but the association was encountered

more often under southern and eastside conditions. Longitudes were typically

east of 119°30’. On the west side from the Sierra, north through the Eldorado

National Forest, the association appears to diminish in occurrence, but it is still

represented at these latitudes on the Toiyabe and Lake Tahoe Basin Management

Unit. Stands can be quite extensive and cover areas of several hundred acres, but

in most cases they are moderate in size and cover a few tens of acres.

Environment

Elevations are wide ranging and evenly distributed above and below 7,500 feet.

A high proportion of stands occur above 8,500 feet reflecting locations in the

south and on the eastside portions of the study area where elevations for similar

plant communities are generally higher. It was sampled as high as 9,520 feet on

the Inyo, and the lowest site was at 5,920 feet on the Stanislaus National Forest.

Aspects commonly face southeast through southwest. Slopes are significantly

steeper than other types. Most are steeper than 20 percent, and occasionally they

exceed 40 percent. The combination of steep slopes and southerly aspects result

in SRI levels that are among the highest in the upper montane and significantly

higher than most other forested plant associations. Sites are characteristically

located on ridge tops and the upper and middle thirds of slopes. Significantly

higher levels of bare ground, surface gravel, and bare rock are present compared
170 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

to most other plant associations in the upper montane. These features are

indications of dry habitats. Stress indexes in these sites is substantially higher

than most other associations.

 Variable Mean Range

Elevation (feet) 8,255 6,660-9,520

Slope (pct.) 30 4-64

Solar radiation index 0.516 0.357-0.591

Bare ground (pct.) 8 1-49

Surface gravel (pct.) 9 0-43

Surface rock (pct.) 7 0-30

Litter (pct.) 77 30-96

Litter depth (inches) 1.1 0.3-2.2

Stress index 0.55 0.39-0.64

Aspect: SE, SW.

Range: All.

Position: Ridges, upper slopes.

Range: Ridgetops, upper, middle and lower slopes, benches.

Vegetation

Stands are characteristically open woodlands with a prominent shrub layer. Tree

cover is among the lowest of any of the upper montane associations. Conversely,

shrub cover is significantly higher than most other sites. The overstory is

characterized by a relatively high component of Jeffrey pine, a dry site indicator.

Red fir is commonly present, and white fir is sometimes a member of stands as

well. In some cases, Jeffrey pine may be the only member of the overstory

although other stands are dominated by red or white fir, and Jeffrey pine becomes

a scattered or missing component. In these cases, the understories are dominated

by greenleaf manzanita or snowbrush and indicate the association.

In most cases, understories show a high abundance of greenleaf manzanita

and Sierra chinquapin. On the Inyo, Toiyabe, and Lake Tahoe Basin Management

Unit a variation of this association occurs that is dominated by snowbrush. There

is no environmental difference, other than location, between these communities,

and they have been combined in the classification. On these sites greenleaf

manzanita, pinemat manzanita, and Sierra chinquapin are usually present to

help verify the association. These species are all dry site indicators in these

forests. Broad seeded rock cress, Coville’s gayophytum, and naked stemmed

eriogonum are dry site indicators in the forb layer, and pussy paws, mountain

pennyroyal, and Sierra wallflower inhabit moderate to dry sites. Bottle brush

squirreltail and western needlegrass are dry site indicators in the grass layer.

Conifer regeneration is low. Although the average was 150 per seedlings per

acre, distributions are skewed, and the median value is only 30. Late seral stands

typically had less than 100 seedlings per acre. Red fir is the most common species

present in the regeneration layer, while white fir and Jeffrey pine occur less often

and in substantially lower numbers. Jeffrey pine regenerates significantly more

often compared to other associations.

Plant species diversity is moderate; however, stands tend to be more diverse

generally than many others in the upper montane. Stands have a moderate

number of species overall, and sites are not dominated by a tree canopy alone.

Several species are often present in the shrub layer, and although shrubs

dominate the understory, several forb species also occupy sites. The number and
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 171

distribution of abundant species is moderate for these forests, and they are

somewhat uniformly distributed between trees and shrubs.

The oldest trees in these stands are typically older than 250 years. Although

average stand ages are not substantially different than many others in these

forests, Jeffrey pine, as a species, can attain a considerable age. Often, it is older

than most other species when it occurs in combination with other species in late

seral stands, and the older average age of many stands appears to lie in the

greater ages attained by Jeffrey pine. The oldest tree measured in this association

was a Jeffrey pine at +427 years. By comparison, the oldest red fir was +396 years,

and the oldest white fir was estimated at +252 years.

Stand replacing disturbance events probably occur in this association at

somewhat higher frequencies than others in the upper montane. Shrubby sites

on steeper, drier, south-facing aspects with irregular tree distributions would

indicate a different fire regime than others in these forests. Shrub layers and

south aspects generally favor larger more intense fires. Conversely, the structure

of the stands with stocking concentrated in relatively large, widely spaced,

somewhat fire resistant individuals and the noncontinuous distribution of the

shrub layer would tend to ensure some level of survival for most species after a

fire. These stands probably experience patchy burns that leave portions of the

stand with little damage while other portions are burned intensely. Isolated large

trees probably escape damage in many cases.

Disturbance elements such as windthrow and avalanche are not common

features of these stands. Insects, disease, and lightning are more common, but

they generally occur in localized situations or on select species. In most cases

disturbances occur continuously at various scales, and this results in the creation

of various sized gaps as well as a persistent shrub understory that is continually

changing through time.

Reproductive strategies such as consistent seed production, germination on

mineral soil, sprouting, or delayed germination of seed until scarified by fire is

present in species on these sites. Jeffrey pine is a consistent seed producer that

does well on mineral seedbeds for example, and greenleaf manzanita, Sierra

chinquapin, and snowbrush are all sprouting species. Snowbrush establishes

well from seed after burns.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance events. Disturbance creates

opportunities for regeneration, but many microhabitats are unsuitable for

regeneration, and conifer establishment is a prolonged process on these sites.

Disturbance also provides opportunities for surviving individuals to increase

growth. Scattered patches probably escape many disturbances and proceed

through a period of regeneration followed by crown closure and self thinning.

Isolated trees and small patches that escape repeated disturbance eventually

mature into larger members of the stand. In time, stands develop an irregular

structure reflecting numerous disturbances and containing large trees that

remain from several stand altering events.

 Cover (percent) Mean Range

Total vegetative 74 30-99

Tree 40 10-79

Shrub 41 1-82

Forb 7 0-53

Grass 4 0-40

Moss 0.4 0-6

Stand age (years) 236 95-402
172 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Diversity index

Simpson 0.28 0.12-0.46

Hill numbers

N0 12.0 4.0-20.0

N1 5.11 2.33-10.25

N2 3.88 2.20-8.64

Characteristic Vegetation

Percent cover

Code Common name Constancy Mean Range

I. Overstory trees

PIJE Jeffrey pine 84 25 3-72

ABMA Red fir 69 20 2-52

ABCO White fir 34 13 1-42

II. Understory trees

ABMA Red fir 56 1 1-6

ABCO White fir 41 1 1-4

PIJE Jeffrey pine 41 1 1-1

III. Shrubs

ARPA9 Greenleaf manzanita 72 19 1-58

CEVE3 Snowbrush 41 24 1-53

CASE3 Sierra chinquapin 38 11 1-37

CECO2 Mountain whitethorn 28 8 1-30

ARNE2 Pinemat manzanita 25 22 1-51

PREM Bitter cherry 25 2 1-10

IV. Forbs

ARPL Broad seeded rock cress 62 1 1-2

GAER Coville’s gayophytum 50 2 1-8

PESE3 Pine woods lousewort 34 1 1-1

CAUM2 Pussy paws 31 1 1-1

ERBR2 Brewer’s daisy 31 2 1-3

ERNUD Naked stemmed eriogonum 31 1 1-2

MOOD Mountain pennyroyal 28 2 1-30

ERPE3 Sierra wallflower 22 1 1-1

V. Grasses and grass-like

SIHY Bottle brush squirreltail 47 3 1-15

STOC1 Western needlegrass 38 2 1-10

Soils

Soils are almost evenly distributed between Inceptisols and Enitsols. In a few

instances Mollisols are present. Most of the Inceptisols are Xerumbrepts with

occasional Xerochrepts. Entisols are typically Xeropsamments and Xerorthents.

Particle size classes are commonly skeletal and sandy, indicating higher levels of

coarse fragments in the profiles. Granitic parent materials are most frequent in

these stands. Some are derived from volcanic materials from a wide range of

 Cover (percent) Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 173

sources such as the andesitic and rhyolitic flow rocks and lahars typical of the

northern portion of the study area and the tephra and tuff deposits from the

eastside near Mammoth Mountain. Soils formed from these substrates are

commonly weathered in place from bedrock, although some are formed from

alluvial and colluvial materials.

Soil depths are moderately deep to deep. Almost 40 percent of the sample

sites had depths greater than 40 inches, and depths less than 25 inches were

infrequent. Topsoil textures are usually sands with some sandy loams and a few

loams. Subsoil textures are similar, but they contain a higher proportion of sands

and fewer loams. These are coarse textured soils that contain significantly higher

proportions of sands than most other sites in the upper montane.

The average AWC of these soils is among the lowest in the forested portions

of the upper montane. Soils typically lie over parent materials that are fractured

and rootable thereby increasing the available moisture supply to vegetation.

Drainage is characteristically excessive reflecting locations on slopes with coarse

textured soils. Erodibility is low to moderate on slopes because of these coarse

textured soils. Soils are significantly warmer than those in most other

associations in the study area. Summertime soil temperatures are commonly

higher than 53°.

 Variable Mean Range

Depth of soil sample (inches) 32 5-40+

Topsoil

Depth (inches) 8 2-23

Coarse fragments (pct.) 22 2-55

pH 6.0 4.7-7.0

Subsoil

Coarse fragments (pct.) 43 3-92

pH 5.9 4.9-7.2

AWC (inches) 2.2 0.2-5.2

Temp (20 inches) (Fahrenheit) 56 38-72

Productivity

Pacific Southwest Region (Region 5) site indexes are significantly less than

dense, well-stocked stands in the study area. Site indexes were generally 3 or 4;

no site index was better than 2. Stand density is also low. Stand density indexes

are characteristically less than 300, and stocking levels are only 34 percent of

values reached in the red fir-white fir association, which is one of the densest in

the upper montane. Stocking also resides in the larger individuals of the stand.

The average quadratic mean diameter for these stands is among the highest of

any of the forested associations in the study area. Tree heights are also

considerably shorter than associations with better site index. The tallest tree

measured was a red fir at 150 feet, while the tallest white fir was 133 feet, and the

tallest Jeffrey pine was 118 feet. The combination of lower site indexes, lower

stand densities, and shorter tree heights result in substantially lower basal area

stocking and cubic and board foot yields in these stands.

Stand structures are irregular. These are open stands with few trees per acre

(fig. 31). The total number of trees per acre is substantially lower than most other

sites. Stands in this association generally carry fewer than 100 trees per acre, and

often they contain less than 50 trees per acre. This stocking is concentrated in a

few large trees. Compared to an uneven-aged structure with a balanced diameter

distribution and similar stocking levels, these stands have far fewer trees in

smaller size classes and an excess of trees in larger size classes. Compared to
174 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 41 14 3 41 1 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag numbers are low, reflecting the open conditions of most stands. Snags

smaller than 11 inches DBH are sparse, but otherwise mortality is somewhat

uniformly distributed among all size classes. Mortality appears to occur more

often in red and white fir in this association. This was particularly so in size

classes smaller than 25 inches. Snags are uniformly distributed between height

classes, but decay classes typically lie between 1 and 3. Logs are commonly

smaller than 30 inches in large end diameter, and most of these are less than 20

feet in length. Logs evidence higher levels of decay than snags. Decay classes

generally lie between 3 and 5.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

25

15

5

30 Figure 31—Number of trees by

diameter class in the Jeffrey pine/

greenleaf manzanita-snowbrush plant

association.

even-aged distributions, they have an excess of trees in both smaller and larger

size classes.

 Variable Mean Range

Region 5 site index 3 2-4

Forest survey site class 4 3-5

Stand density index 177 50-324

Quadratic mean diameter 26.1 9.8-40.7

Softwood volume (mcf/ac) 4.3 1.6-12.9

Softwood volume (mbf/ac) 28.0 10.5-92.6

Softwood basal area (sq ft/ac) 122 27-307

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 175

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0.5 0.6 0.2 0.7 0.5 2.5

Snag height (feet)

<20 - - 0.2 - 0.3 0.2 0.7

20-50 - 0.5 0.2 0.1 0.1 - 0.9

>50 - - 0.2 0.1 0.3 0.3 0.9

Snag decay class

1 - 0.5 0.2 0.1 0.2 - 1.0

2 - - - - 0.2 0.2 0.4

3 - - - - 0.2 0.3 0.5

4 - - - 0.1 - - 0.1

5 - - 0.4 - 0.1 - 0.5

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 2.7 4.0 1.7 1.0 9.4

Log length (feet)

<20 2.3 2.1 1.0 0.4 5.8

20-50 0.3 1.3 0.6 - 2.2

51-100 0.1 0.6 0.1 0.6 1.4

>100 -----

Log decay class

1 -----

2 0.3 0.6 0.1 - 1.0

3 0.6 1.6 0.3 0.3 2.8

4 0.7 1.2 0.6 0.4 2.9

5 1.1 0.6 0.7 0.3 2.7

Wildlife

Forage values in these stands appear to be moderate. Several species are preferred

or staple species in the large game diet, and constancy and cover values seem to

be high enough to provide a reasonable food source. In the shrub layer, mountain

whitethorn and bittercherry are preferred species, and greenleaf manzanita and

snowbrush are staples. In the forb layer naked stemmed eriogonumand Brewer’s

daisy are staples, and bottle brush squirreltail and western needlegrass are

staples in the grass layer. Evidence of deer and pocket gopher was commonly

observed in this association.

Range

Range potential appears to be transitory as livestock move to primary range sites

such as meadows and other moist habitats. Cattle presence was generally

observed in these stands. Forage values lie primarily in the grass layer. Bottlebrush squirreltail and western needlegrass are secondary forage species.
176 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Constancy is reasonably high for these species, although cover values appear to

be moderate to low. All other species commonly occurring in the association are

of low range value, and overall contributions to the range diet are probably low.

Management Recommendations

This association has been harvested only in the southern portion of the range.

Harvesting has generally been a form of improvement cutting done either as

salvage or stand improvement. In a few instances clearcutting was applied on

some of the better sites. Where this was accomplished, planting with Jeffrey pine

has succeeded in reforesting the stand in most cases. Few red fir naturals appear

in such stands, and it is important to observe that only the better sites appear to

have received this treatment.

These stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable, but species composition, site index,

or stand density are limiting, and the ability of sites to respond to treatment are

uncertain as slopes increase and site indexes decrease. The ability to predict

results of treatment under these conditions are not based on wide experience or

research at this time.

The open nature of these stands in combination with high shrub cover indicates

that natural regeneration and establishment is a lengthy and variable process

under most conditions. Competition from existing shrubs appears to be

potentially severe, and trees can be under moisture stress for long periods.

Mortality rates in seedling classes are probably high, and seed flow onto sites is

low due to the low density of trees. Because site indexes are lower, planting

success and stand establishment can be expected to diminish. Under any cutting

method, these sites will require follow up vegetation control for conifer

establishment in reasonable time frames, and needed vegetation control can be

anticipated until the stand is established. Cutting methods relying on natural

regeneration can be expected to result in erratic stocking and require long time

periods for establishment.

Silvicultural systems, cutting methods, stocking levels, or regeneration strategies

appropriate for stands in this plant association have not been determined, and

successional sequences are not well understood. Recommendations for

harvesting better sites at the present time would be to treat stands in this type

with caution and expect that results can be uncertain. Management emphasis on

poorer sites may be more appropriately directed at maintaining existing wildlife

habitat, species richness, and the landscape level diversity such plant

communities provide.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 177

Jeffrey Pine/Mountain Whitethorn-Sagebrush Association

Pinus Jeffreyii/Ceanothus cordulatus-Artemesia tridentata

PIJE/CECO2-ARTR

CPJCPJ14

Sample size: 18

Distribution

The Jeffrey pine/mountain whitethorn-sagebrush plant association lies

throughout the central and southern Sierra Nevada. The most southerly stands

sampled were on the Sequoia and Inyo National Forests near Onion Meadow

Peak and Brown Cow Camp, but locations generally lie north of the San Joaquin

River near latitude 37o30’. As one travels north and east through the Sierra the

association becomes more common. Longitudes typically lie between 119o

 and

120o30’. Stands can be somewhat extensive such as near Luther Pass, but they

appear to lie in the range of 5 to 50 acres in most cases.

Environment

Elevations for this plant association are wide ranging, but it commonly occurs at

middle to lower elevations. Sites are found most frequently below 8,000 feet, and

the lowest stand sampled was on the Eldorado National Forest at 6,820 feet. Aspects

characteristically face southeast through southwest on slopes that are generally

less than 30 percent. Similar to other Jeffrey pine associations, SRI levels are among

the highest in the upper montane. Stands frequently occupy middle and lower

slope positions; and as one ascends, a transition to other Jeffrey pine associations,

such as Jeffrey pine/greenleaf manzanita-snowbrush or Jeffrey pine/huckleberry

oak, often occur. These stands have significantly more bare ground and surface

gravel than most other sites, and litter thickness is substantially less. These features

are indicative of drier habitats. Microrelief is characteristically uniform.
178 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Variable Mean Range

Elevation (feet) 7,967 6,820-9,360

Slope (pct.) 20 1-51

Solar radiation index 0.533 0.488-0.594

Bare ground (pct.) 12 1-35

Surface gravel (pct.) 14 1-40

Surface rock (pct.) 3 0-12

Litter (pct.) 69 20-96

Litter depth (inches) 0.8 0.2-1.6

Stress index 0.52 0.38-0.62

Aspect: SE, SW.

Range: NE, SE, SW.

Position: Ridges and slopes.

Range: Ridgetops, upper, middle, and lower slopes, benches.

Vegetation

Stands are commonly open woodlands with scattered patches of shrubs. Total

tree cover is among the lowest of any of the forested associations. Conversely,

shrub cover is considerably higher than most other sites. The overstory is

characterized by the presence of Jeffrey pine. Red fir is generally present as well,

and occasionally lodgepole pine and white fir are part of the stand composition.

Red fir, lodgepole pine, and white fir are often mesic site indicators, and Jeffrey

pine is indicative of somewhat drier conditions. In a few cases Jeffrey pine may

be the only member of the overstory, but other stands can be dominated by red

fir, white fir, or, in some cases, Lodgepole pine. In these cases understories are

dominated by mountain whitethorn, sagebrush, bitter brush, or rabbit brush and

indicate the association.

The shrub layer is often a mix of species; however, they can generally be

separated into two distinct types of communities that occur on westside or

eastside forests. Westside stands are dominated by mountain whitethorn

sometimes mixed with sagebrush. Eastside stands, on the other hand, can be

dominated by any one of four species: mountain whitethorn, sagebrush, bitter

brush, and sticky-leaved rabbit brush. Usually two of the four species occur on

any particular site, but eastside stands dominated by sagebrush, bitter brush,

and rabbit brush often do not contain mountain whitethorn. Thus, westside

stands tend to be clearly dominated by mountain whitethorn; whereas eastside

stands are mixed shrub communities, and mountain whitethorn may actually

become a rare component in some cases. Two plant associations may actually

exist in this complex, but environmentally they are similar except for the eastwest geographic separation. They have been combined at this time in the

classification and named to indicate the two possible communities. All of these

shrub species indicate moderate to dry moisture regimes.

There is also a westside plant community that visually looks like the Jeffrey

pines/mountain whitethorn-sagebrush association but contains Fresno

ceanothus (ceanothus fresnensis) instead of mountain whitethorn in the shrub

layer. It has been observed, but not sampled, in small areas near Liberty Hill on

the Stanislaus National Forest. It occurs only on soils derived from volcanic

lahars, and in all other respects appears to be similar environmentally to the

Jeffrey pine/mountain whitethorn-sagebrush association. It is an uncommon

plant community in the central and southern Sierra, and stands should be

classified as a part of the Jeffrey pine/mountain whitethorn-sagebrush

association at this time.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 179

Broad seeded rockcress, Coville’s gayophytum, and naked stemmed

eriogonum in the forb layer are indicative of drier sites; mountain pennyroyal

and Sierra wallflower generally occupy moderate to dry habitats; and mountain

violet and Kellogg’s bedstraw occupy moderate habitats. Bottle brush squirreltail

and western needlegrass are dry site species present in the grass layer. The

overall mix of common species in each life form of this association is indicative of

moderate to somewhat dry conditions.

Conifer regeneration is among the lowest of any association in the upper

montane. The average number of seedlings per acre is 100, but distributions are

skewed, and median values are only 60. Stands typically have less than 100

seedlings per acre, and they are generally clumped rather than distributed

evenly within the stand. Red fir is typically present in the tree regeneration;

Jeffrey pine is present less often, and white fir is occasionally present, but no

species is dominating the regeneration layer on most sites. Jeffrey pine

regenerates with significantly higher frequency compared to other associations.

Plant species diversity is one of the highest in the upper montane. It has only a

few less species on average than the Quaking aspen/mountain pennyroyal and

western juniper/sagebrush associations which have some of the highest numbers

of species in these forests. Although several tree species are often present, lower

tree cover and high numbers of shrub, forb, and grass species with relatively

uniform cover result in abundant species that are distributed in several life forms.

The oldest trees in these stands are typically older than 250 years. Although

average ages of these stands are not substantially different from many others in

these forests, Jeffrey pine, as a species, can attain a considerable age. Often, it is

older than most other species when it occurs in combination with other species in

these late seral stands, and the older average stand ages of many stands appears

to lie in the greater ages attained by Jeffrey pine. The oldest tree sampled was a

Jeffrey pine at +457 years compared to the oldest red fir at +310 years, the oldest

white fir at +270 years, and the oldest lodgepole pine at +257 years.

Stand replacing events probably occur in this association at somewhat higher

frequencies than many others in the upper montane. Shrubby sites on south

aspects with patchy tree distributions would indicate a different fire regime than

others in these forests. Shrub layers and south aspects favor larger, more intense

fires. Conversely, the structure of stands with stocking concentrated in relatively

large, widely spaced, somewhat fire resistant individuals and the non-continuous

distribution of the shrub layer would tend to ensure some level of survival of

many species after fire. Thus, although stand replacing fires may occur, these

stands probably experience patchy burns with some portions of the stand

completely consumed, and others are left with little damage. Isolated large trees

probably escape damage in many cases. Disturbance elements such as windthrow

and avalanche are not common features of these stands. Insects, disease, and

lightning are more common, but they generally occur in localized situations or

on select species and seldom are involved in stand replacement.

Reproductive strategies such as consistent seed production, widespread

seed dispersal, germination on mineral soil, sprouting, or delayed germination

of seed until scarified by fire is present in many species on these sites. Jeffrey

pine is a consistent seed producer that does well on mineral seedbeds for

example, and both mountain whitethorn and bitter brush tend to be sprouters

after fire. Sagebrush, on the other hand, is a non-sprouter that appears to maintain

dominance through competition. It may lose dominance on sites after fire, and it

may actually indicate sites that have not experienced a recent fire. In many cases

the species composition of future stands is determined by species currently on

these sites.

Disturbance in these stands creates opportunities for regeneration, but in most

cases it appears that stand regeneration is a prolonged process. Disturbance also

provides opportunities for surviving individuals to increase growth. Scattered
180 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

patches of trees probably escape repeated disturbances and proceed through

periods of crown closure and self thinning. Isolated individuals and small patches

that escape disturbance eventually mature into larger members of the stand. In

time, the stand develops an irregular structure reflecting numerous disturbances,

and containing large trees as the survivors of multiple disturbances events.

Cover (percent) Mean Range

Total vegetative 76 30-97

Tree 36 1-63

Shrub 28 1-77

Forb 19 1-65

Grass 15 1-55

Moss 0.1 0-1

Stand age (years) 243 96-409

Diversity index

Simpson 0.20 0.03-0.41

Hill numbers

N0 15.3 10.0-25.0

N1 7.64 3.82-16.43

N2 6.94 2.46-31.50

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

PIJE Jeffrey pine 94 16 1-37

ABMA Red fir 89 15 1-48

PICO Lodgepole pine 28 9 2-17

ABCO White fir 22 17 2-36

II. Understory trees

ABMA Red fir 67 1 1-3

PIJE Jeffrey pine 50 1 1-2

ABCO White fir 28 1 1-1

III. Shrubs

CECO2 Mountain whitethorn 56 20 1-77

ARTR Sagebrush 39 14 1-30

CHVI4 Sticky leaved rabbit brush 22 10 5-15

PUTR Bitter brush 22 16 1-60

IV. Forbs

ARPL Broad seeded rock cress 72 1 1-5

GAER Coville’s gayophytum 61 3 1-60

ERBR2 Brewer’s daisy 44 4 1-25

MOOD Mountain pennyroyal 44 7 1-25

ERNUD Naked stemmed eriogonum 39 2 1-5

ERPE3 Sierra wallflower 33 1 1-1

PESE3 Pine woods lousewort 33 1 1-1

VIPU Mountain violet 33 1 1-1

PHHY Waterleaf phacelia 28 1 1-2

PHRA2 Branching phacelia 28 1 1-1

KEGA Kellogg’s bedstraw 22 3 1-8
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 181

V. Grasses and grass-like

SIHY Bottle brush squirreltail 72 7 1-40

STOC1 Western needlegrass 61 7 1-25

BRMA3 Large mountain brome 33 6 1-23

CARO1 Ross’ sedge 33 4 2-15

STEL1 Elmer’s needlegrass 28 9 1-20

ELGL Blue wildrye 28 3 1-8

POBO1 Bolander’s bluegrass 22 1 1-1

STCA1 California needlegrass 22 8 1-15

Soils

Soils in this association are commonly Inceptisols, but occasional Entisols and

rare Mollisols are also encountered. Most of the Inceptisols lie in the Xerumbrept

great group with a few Cryumbrepts and Cryochrepts also present. Entisols are

usually Xeropsamments. Particle size classes are often skeletal, but sandy, loamy,

and medial soils can also be present in a some cases. Parent materials are usually

granitic; however, some of these soils are derived from volcanic lahars, and a few

developed from other volcanic sources such as the andesitic and rhyolitic flow

rocks and tuff deposits typical in eastern portions of the study area. Rare samples

were derived from metamorphic deposits. These soils are usually formed in

place from bedrock although occasional stands occur on soils formed from

alluvium and a few are formed from glacial till and glacial outwash deposits.

Soil depths are generally moderately deep to deep. In some cases they can be

quite deep. Approximately two-thirds of the samples had depths greater than 40

inches although rare sites had depths less than 25 inches. Topsoil textures are

usually sandy loams with occasional sands. Loams are seldom encountered.

Subsoils are also sandy loams with some sands and loams.

The AWC of these sites is variable, but, in general, they are not substantially

different from many moderate sites in the study area. Bedrock formations were

typically fractured and rootable and therefore able to supply additional moisture

to these stands. Sites are often excessively drained due to a combination of coarse

textures and locations on slopes. Erodibility is low to moderate due also to the

coarse soil textures and moderate slopes. These are warm soils. Temperatures

are among the warmest in these forests, and they are significantly higher than

those in most other associations. Summertime soil temperatures on many sites

exceed 53o

 Fahrenheit.

Variable Mean Range

Depth of soil sample (inches) 35 17-40+

Topsoil

Depth (inches) 10 3-22

Coarse fragments (pct.) 20 2-80

pH 6.0 5.5-6.5

Subsoil

Coarse fragments (pct.) 37 4-90

pH 6.1 5.0-7.0

AWC (inches) 2.8 0.1-5.3

Temp (20 inches) (Fahrenheit) 56 44-66

Characteristic Vegetation (continued)

Percent cover

 Code Common name Constancy Mean Range
182 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Productivity

Pacific Southwest Region (Region 5) site indexes are considerably lower than

other well stocked stands in the upper montane. Typical site indexes were 3. In a

few cases they were 2 or 4. Stand density is also substantially lower than other

dense stands in the study area. Most stand density indexes are less than 300, and

average stocking levels based on stand density indexes are only 48 percent of

those attained in fully stocked stands such as the red fir-white fir association,

which is one of the densest in the study area. Tree heights are commonly shorter

than those on better sites. The height of the tallest Jeffrey pine was measured at

147 feet, and the height of the tallest red and white fir was 132 and 127 feet

respectively. As a result of lower site classes, shorter heights, and lower stand

densities, cubic and board foot volumes are moderate to low.

Stand structures are irregular. These are open stands with lower numbers of

trees per acre (fig. 32). Stands characteristically carry less than 200 trees per acre

distributed among all size classes. Compared to an uneven-aged structure with a

balanced diameter distribution and similar stocking levels, these stands have too

few trees in size classes below 24 inches and an excess of trees in size classes above

30 inches. When compared to an even-age distribution, trees in size classes less than

24 inches and larger than 30 inches are higher than needed at similar stocking levels.

Variable Mean Range

Region 5 site index 3 2-4

Forest survey site class 4 3-5

Stand density index 252 106-491

Quadratic mean diameter 19.4 8.2-29.7

Softwood volume (mcf/ac) 5.5 2.5-8.7

Softwood volume (mbf/ac) 34.4 12.5-58.8

Softwood basal area (sq ft/ac) 157 56-280

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

30

40

50

60

70

80

90

100

110

Figure 32—Number of trees by

diameter class in the Jeffrey pine/

mountain whitethorn-sagebrush plant

association.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 45 13 6 31 3 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent 1 1 - - - -
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 183

Coarse Woody Debris

Snag densities are moderate compared to other plant associations in the upper

montane. Mortality appears to be distributed among all size classes, although higher

levels of snags less than 11 inches and between 30 and 40 inches DBH occurred in the

sample. Mortality was also distributed more heavily in red and white fir particularly

in size classes smaller than 25 inches. Snags occurred uniformly in all height classes,

but decay classes generally lie between 1 and 3. Logs typically were smaller than 30

inches in large end diameter, and they were characteristically less than 50 feet in

length. Log decay classes were 4 and 5 in the samples.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 2.0 0.5 0.3 0.4 2.6 0.8 6.6

Snag height (feet)

<20 0.8 - - 0.2 1.3 0.3 2.6

20-50 1.2 - - 0.2 - - 1.4

>50 - 0.5 0.3 - 1.3 0.5 2.6

Snag decay class

1 1.4 0.5 - - 1.3 - 3.2

2 0.6 - 0.3 - - 0.3 1.2

3 - - - - 1.3 0.5 1.8

4 - - - 0.4 - - 0.4

5 - - - - - --

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 1.0 1.3 0.7 0.7 3.7

Log length (feet)

<20 0.3 1.0 0.4 0.4 2.1

20-50 0.7 - 0.3 - 1.0

51-100 - 0.3 - 0.3 0.6

>100 - - - - -

Log decay class

1 -- - - -

2 -- - - -

3 -- - - -

4 1.0 1.0 0.7 0.4 3.1

5 - 0.3 - 0.3 0.6

Wildlife

These stands appear to offer good forage possibilities for large game. Mountain

whitethorn and bitter brush are preferred forage species, and sagebrush,

Brewer’s daisy, and naked stemmed eriogonum are staples in the shrub and forb

layer. Bottle brush squirreltail, western needlegrass, large mountain brome, and

Ross’ sedge are all staples in the grass layer. All of these species appear to be
184 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

occurring with high enough constancy and cover to contribute to the large game

diet. The open shrubby nature of the stands together with good forage possibilities

would appear to make them preferred sites for big game, but observations of deer

presence were only occasional. Sign of gophers was also uncommon on these sites.

Range

Range potential appears to be transitory as livestock move to primary range sites

such as meadows and other moist habitats. Cattle presence was common on

these sites. Large mountain brome is a primary forage species, and bottle brush

squirreltail and western needlegrass are secondary forage species. Most of the

shrub and forb component, however, are low value forage species, and it appears

that range forage potential is low in these late seral stands.

Management Recommendations

Some harvesting has taken place in these stands, particularly on the eastside.

Most harvests have been in the form of improvement or salvage cutting with no

defined regeneration plan. In recent years clearcutting has been practiced in

some cases to create even-aged stands. Planting with Jeffrey pine has been

performed in most of these. Results are mixed, and the reason for failures appear

to be variable. On some sites competition from whitethorn appears to be

significant, and seedlings can be under moisture stress for long periods. Early

successional sequences in this association are not well understood, and

regeneration patterns are unclear. Techniques for incorporating red fir as part of

the species mix on these sites have not been developed, and it does not seem to be

regenerating these stands naturally. Until experience is gained, caution should

be exercised in treating these stands, and prolonged periods to achieve acceptable

stocking should be expected on many sites.

These stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable, but species composition, site index,

and stand density are limiting, and the ability of sites to respond to treatment are

uncertain. The ability to predict results of treatment are not based on wide

experience or research results at this time. The open nature of these stands

indicates that regeneration and establishment is a lengthy and variable process

under most conditions.

Recommendations for harvesting on high sites can involve both even- and

uneven-aged silvicultural systems and a variety of cutting methods. Due to

possible competition from shrub species such as mountain whitethorn, unevenaged systems relying on single tree selection and natural regeneration is not

recommended. Openings for regeneration should be kept small, probably less

than 5 to 10 acres. A regeneration strategy recommended at this time would

involve site preparation to reduce the shrub component, planting with Jeffrey

pine as a preferred species and follow up vegetation treatment to control shrub

competition, and developing the species composition that occurs in late seral

stands. In stands with low site index, limited opportunities exist for salvage

when it occurs, but in such stands it would appear that woody debris left in the

form of snags and logs for wildlife or part of the nutrient pool would be better

direction. Management emphasis on low sites should provide for existing wildlife

habitat, plant species richness, and the landscape level diversity this association

provides to the upper montane.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 185

Red Fir-White Fir-Jeffrey Pine Association

Abies magnifica-Abies concolor-Pinus Jeffreyii

ABMA-ABCO-PIJE

CFRCFW12

Sample size: 31

Distribution

The red fir-white fir-Jeffrey pine plant association is widespread in the central

and southern Sierra Nevada; however, it was sampled primarily on the westside

of the range. Latitudes and longitudes spanned the range of the study area.

Stands generally vary in size from smaller than 5 acres to over 100 acres.

Environment

This association is located at middle to lower elevations. Elevations generally lie

between 6,500 feet and 8,000 feet. The lowest elevation encountered was on the

Eldorado National Forest near Robbs Valley, and the highest was located on the

Kern Plateau near Beer Keg Meadow. These locations reflect the gradual rise in

elevation of similar plant communities from north to south. Aspects are varied,

but a large portion lie on south facing slopes where solar radiation levels are

substantially higher than many other sites. Stands often occur on upper slopes

with a few located on ridgetops. Slopes are moderately steep. They usually lie

between 20 and 35 percent. Stands have significantly less surface gravel and

deeper litter than drier sites commonly encountered in these forests. Stress

indexes are typically high due to locations at lower elevations and occurrences

on upper slope positions.
186 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 7,507 6,300-8,800

Slope (pct.) 25 0-57

Solar radiation index 0.498 0.333-0.567

Bare ground (pct.) 5 0-40

Surface gravel (pct.) 2 0-10

Surface rock (pct.) 4 0-20

Litter (pct.) 89 52-99

Litter depth (inches) 1.9 0.2-6.0

Stress index 0.49 0.42-0.59

Aspect: SE, SW.

Range: All.

Position: Upper slopes.

Range: All.

Vegetation

These are moderately dense forested stands with light understory vegetation.

Overstory layers are characterized by the presence of white fir and Jeffrey pine in

mix with red fir. The mix appears to reflect long term response to environmental

conditions such as different fire regimes resulting from lower elevations and

southerly aspects. In such environments shade intolerant species such as Jeffrey

pine are able to establish and grow in combination with shade tolerant species

such as red and white fir.

Understories are somewhat sparse. Sierra chinquapin can occasionally

become a major component in the shrub layer and dominate understories, but in

most cases shrubs occur as scattered patches and individuals. Sierra chinquapin

and infrequent occurrences of greenleaf manzanita indicate drier conditions, and

creeping snowberry occurs in moderate habitats. The forb layer usually contains

Kellogg’s bedstraw, white flowered hawkweed, mountain violet, and white

veined wintergreen as indicators of mesic sites. The sparse grass layer is

composed of both dry and mesic species all occurring at low constancy. An

important element in these understories is the presence of several shrub and forb

species which occur at low constancy, but can dominate sites in early successional

sequences. In the shrub layer these are species such as mountain whitethorn,

bitter cherry, and snowbrush. In the forb layer bracken fern, Drew’s silky lupine,

and Anderson’s lupine are further examples.

Conifer regeneration is moderate. The average number of seedlings exceeds

500 per acre, and sites usually have more than 250 per acre. Regeneration is

usually composed of both red and white fir, but Jeffrey pine is an infrequent

component in the regeneration layer, and numbers of this species are low.

However, both Jeffrey pine and white fir are regenerating significantly more

often than in most other upper montane associations.

Plant species diversity is moderately low. Compared to other associations in

the upper montane, the total number of species is mid-range and influenced by

the presence of relatively few species in the shrub, forb, and grass layers.

Abundant species reside in the tree component that far outweigh cover values in

other life forms.

The oldest trees in these stands are usually older than 200 years. Average ages

of these stands are not substantially different in age than others in these forests;

however, individual Jeffrey pine can attain a considerable age in the Sierra Nevada.

Often Jeffrey pine is older than most other species when it occurs in combination in

these late seral stands, and the older average stand ages attained in many cases

appear to lie in the greater ages acquired by this species. The oldest tree sampled in

this association was a Jeffrey pine at +556 years. The oldest white fir was estimated
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 187

at +375 years, and the oldest red fir sampled was +251 years.

Since stands lie adjacent to lower montane forests with high fire frequency and

more intense burns, stand replacing fires probably occur more often in this

association than many others in the upper montane. The location of many stands

on warm south aspects near ridges and upper slopes would further indicate a high

fire frequency. On the other hand, large relatively fire resistant individuals tend to

preclude the loss of all individuals from many fires, and no clear picture of larger

more intense fires emerges from these stands. Stand structures indicate a fire

regime characteristic of other dense stands in the upper montane with small gap

formation and few stand replacing events. Stands probably experience both small

scale patchy burns with infrequent large scale stand replacing fires typical of the

upper montane in most cases. Other disturbance elements such as windthrow and

avalanche are not widespread features of these stands. Insects, disease, and

lightning are more common, but mortality from these factors often occurs in

localized situations or in select species. Disturbance from all elements occurs

continuously on various scales in these stands, and this appears to result in the

creation of various sized gaps and constantly changing structures through time.

Reproductive strategies such as consistent seed production are present in

most of the tree species in these stands. Sprouting or delayed germination of seed

until scarified by fire is present in many of the shrub species. Sierra chinquapin

and greenleaf manzanita are sprouting species for example. Mountain

whitethorn, several lupine species, and western bracken fern are not common

understory species in this association; nevertheless, they all have the ability to

reoccupy disturbed sites rapidly through long term storage of viable seeds or

rhizomes. Shade intolerant species such as Jeffrey pine are undoubtedly

maintained by disturbances that open stands and provide seed beds.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. After disturbance, the most likely

successional sequence involves early dominance by shrubs, forbs, and grass.

These early communities can be quite persistent on the landscape, and replacement

by trees can be a prolonged process. Once regeneration is established, however, it

grows, self-thins, and matures while other portions of the stand continue to

undergo disturbance. In time, a patchy distribution of trees emerge with mixed

species. Several size and tree classes are represented, including a substantial

portion of larger trees. The stand exhibits an irregular structure with many small

relatively even-aged patches. As stands occupy sites for longer periods, successive

disturbances continue to develop and maintain stand structures until an infrequent

stand replacing event occurs and a new stand emerges.

 Cover (percent) Mean Range

Total vegetative 76 39-97

Tree 65 30-90

Shrub 10 0-78

Forb 13 0-90

Grass 2 0-40

Moss 0.6 0-15

Stand age (years) 208 75-379

Diversity index

Simpson 0.37 0.13-0.85

Hill numbers

N0 11.9 3.0-22.0

N1 4.58 1.48-9.19

N2 3.36 1.18-7.71
188 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

ABCO White fir 90 26 1-80

PIJE Jeffrey pine 90 18 2-50

ABMA Red fir 84 29 1-70

II. Understory trees

ABMA Red fir 81 2 1-5

ABCO White fir 68 1 1-6

PIJE Jeffrey pine 29 1 1-1

III. Shrubs

CASE3 Sierra chinquapin 32 17 1-78

ARPA9 Greenleaf manzanita 23 2 1-4

SYAC Creeping snowberry 26 5 1-15

IV. Forbs

PESE3 Pine woods lousewort 55 1 1-6

KEGA Kellogg’s bedstraw 52 1 1-60

HIAL White flowered hawkweed 32 2 1-11

PHHY Waterleaf phacelia 32 1 1-5

VIPU Mountain violet 32 1 1-70

COMA4 Spotted coral root 29 1 1-1

PYPI White veined wintergreen 29 1 1-1

APMEF Western dogbane 26 1 1-1

CHBR3 Brewer’s golden aster 26 1 1-1

GAER Coville’s gayophytum 26 3 1-15

V. Grasses and grass-like

None

Soils

Soils are predominantly Inceptisols and typically classified as Xerumbrepts or

occasional Xerochrepts. Entisols are rarely encountered in this association.

Particle size classes are often loamy and indicate lower levels of large coarse

fragments in the profile. These soils are characteristically formed from granitic

parent materials, and volcanic or other parent materials are rarely encountered.

These soils form from a variety of sources. They usually develop in place from

bedrock; however, they are often formed from deposited materials such as

colluvium, alluvium, or glacial tills.

Soils in these stands are deep. They are among the deepest in the upper

montane, and they are substantially deeper than most other sites. Typical depths

exceed 40 inches, and rarely are they less than 35 inches. Topsoil textures are

commonly sandy loams with rare sands and loams. These top soils have a

considerably higher proportion of sandy loams than soils in most other

associations. Subsoils show a similar distribution to the topsoils except sands

occur more frequently. Coarse fragments in both topsoil and subsoil are very low.

The average coarse fragment content in the topsoil is the lowest of the forested

associations in the upper montane. Topsoils commonly contain less than 15 percent

coarse fragments. Coarse fragments in the subsoil are typically less than 35 percent.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 189

The AWC of these sites is one of the highest of these forested associations.

This reflects the deep soils, finer textures, and lower coarse fragment contents

experienced on these sites. Soils are typically well drained. Occasional sites with

excessive drainage tend to lie on coarse textured soils with steeper slopes.

Bedrock formations were typically fractured and rootable thereby providing

additional access to stored water. Erodibility is moderate to high based on soil

textures and slopes encountered on individual sites.

 Variable Mean Range

Depth of soil sample (inches) 39 28-40+

Topsoil

Depth (inches) 8 3-20

Coarse fragments (pct.) 13 1-52

pH 6.0 5.2-6.9

Subsoil

Coarse fragments (pct.) 26 5-80

pH 5.8 5.0-6.8

AWC (inches) 3.8 1.2-6.4

Temp (20 inches) (Fahrenheit) 50 40-62

Productivity

Site indexes average 2. In the majority of stands they are 2 and better, and they are

substantially higher than in many other stands of the upper montane. Stand

densities are moderate. They are usually higher than 300, and stocking levels

based on stand density indexes average as much as 75 percent of those attained in

fully stocked stands of the red fir-white fir plant association, which is one of the

densest in the upper montane forests. Average heights of dominant trees are as tall

as those attained in stands of the red fir association. The tallest tree in this

association, for example, was a Jeffrey pine measured at 198 feet, while the tallest

white fir was 195 feet, and the tallest red fir measured 190 feet. Cubic foot and

board foot yields are quite high, but they are somewhat lower than those in the red

fir or red fir-white fir plant associations because of relatively lower stand densities.

Stand structures are irregular. In general, however, distributions approach

those of an uneven-aged stand (fig. 33). As is typical for most stands in these

forests, when they are compared to uneven-aged stands with similar stocking

levels and balanced diameter distributions, they carry a deficit of trees in size

classes smaller than 18 inches and an excess of trees larger than 30 inches.

Compared to an even-aged distribution with equivalent stocking levels, both

smaller size classes and larger size classes are over-represented. They closely

parallel the distributions of typical late seral red fir dominated stands.

Variable Mean Range

Region 5 site index 2 0-4

Forest survey site class 3 1-5

Stand density index 386 101-870

Quadratic mean diameter 23.9 9.6-37.9

Softwood volume (mcf/ac) 12.0 4.7-25.5

Softwood volume (mbf/ac) 77.5 11.4-187.6

Softwood basal area (sq ft/ac) 287 56-560

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
190 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 39 38 2 20 1 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag numbers are moderately high. Snags less than 18 inches diameter are

abundant reflecting mortality related to thinning of smaller suppressed

individuals. Mortality is distributed relatively uniformly among the remaining

size classes, and although all species experience losses they are more than twice

as large in red fir compared to other species. Snags are commonly shorter than 50

feet reflecting a tendency of large standing snags to break off with increasing

age. They are relatively sound; the majority lie in decay classes 1 and 2. Logs are

somewhat uniformly distributed among size classes, and logs larger than 30

inches in large end diameter are relatively abundant. Most logs are less than 50

feet in length, and they lie in decay classes between 3 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 8.9 4.2 1.4 0.6 1.4 1.4 17.9

Snag height (feet)

<20 4.5 0.8 0.5 0.2 0.3 0.5 6.8

20-50 2.2 1.7 0.5 0.2 0.6 0.5 5.7

>50 2.2 1.7 0.4 0.2 0.5 0.4 5.4

Snag decay class

1 - 0.9 0.5 0.2 0.3 0.3 2.2

2 8.9 2.5 0.5 - 0.6 0.2 12.7

3 - 0.8 0.4 0.4 0.4 0.9 2.9

4 - - - - - --

5 - - - - 0.1 - 0.1

Figure 33—Number of trees by

diameter class in the red fir-white firJeffrey pine plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

30

40

50

60

70
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 191

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 3.0 7.3 7.0 5.3 22.6

Log length (feet)

<20 1.0 4.6 3.7 1.3 10.6

20-50 1.3 2.0 2.3 1.7 7.3

51-100 0.7 0.7 0.7 1.6 3.7

>100 - - 0.3 0.7 1.0

Log decay class

1 - - 0.3 - 0.3

2 1.0 1.3 1.3 1.0 4.6

3 1.3 4.0 2.7 0.7 8.7

4 0.7 1.7 1.7 2.3 6.4

5 - 0.3 1.0 1.3 2.6

Wildlife

Stands in this association may offer some hiding and thermal cover to large

game, but forage possibilities appear transitory. Of the species occurring in this

association only occasional greenleaf manzanita or waterleaf phacelia are staples

in the large game diet, and constancy and cover values for these species are low.

Nevertheless, deer sign on these sites was common, and pocket gopher were

often observed as well.

Range

These are transitional range forage sites that are used by livestock to access

primary range such as meadows and other moist habitats. Cattle presence was

generally observed within stands. Grass is essentially absent, and all other

species occurring with reasonable constancy and cover are low value forage

species. These late seral stands appear to offer only marginal livestock forage

potential.

Management Recommendations

Many stands have been harvested in the study area. Early harvests were directed

at improvement cuttings, but more recently, harvests in the form of clearcutting to

develop even-age stands has been practiced. Little reliance has been placed on

obtaining natural regeneration in such situations. Most sites have been planted to

Jeffrey pine. Results are varied, and this practice has diminished in recent years.

Many well stocked and growing Jeffrey pine plantations are present in the study

area. Failures are probably due to a variety of factors; however, these sites are some

of those in the upper montane forests that have the potential for serious competition

from shrubs and, in some cases, forbs such as lupine and bracken fern.

Although original cover values are rarely high, several understory species

have the ability to rapidly occupy freshly disturbed sites through germination of

seed stored in the soil or resprouting. Sierra chinquapin, greenleaf manzanita,

mountain whitethorn, bitter cherry, squaw currant, several lupine species, and

bracken fern are such species, and all are present in varying degrees in these

stands. In some cases they are already major understory components of existing

stands, and they can quickly dominate a specific site.

Stands have high productive capacity and flexibility for management. Stand

structures are variable, and options for silvicultural systems and cutting methods

can vary to take advantage of the shade tolerance and high stand densities
192 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

attainable. Natural regeneration can be a viable option. Stand openings should

be kept small and seed source near. Topsoils on some sites can be shallow, and

site preparation should be done with care. On north facing slopes small clearcuts

can be utilized, but on south aspects shelterwood cutting or a silvicultural

system that maintains constant tree cover is recommended. Early shrub, forb,

and grass competition should be anticipated when openings are created. In

particular, sites at lower elevations on south aspects can become occupied with

species that offer serious competition to new seedlings. Most reforestation

prescriptions in this association should thus plan for vigorous vegetation control

early in the life of any plantation. As techniques for successfully planting white

and red fir under field conditions improve, species composition in reforestation

should begin to reflect the natural species distributions on these sites.

These sites also have the potential to contribute to wildlife values. In their

present condition they are an important source of snags especially in smaller size

classes, and through management, they can continue to provide high levels of

snags for a period of time after harvest. Many of the species expected to offer

competition to conifer seedlings are also preferred or secondary large game food

sources. Mountain whitethorn and bitter cherry are preferred forage, and

snowbrush and greenleaf manzanita are staples in the large game diet. Under

some circumstances, careful vegetation management early in the life of

plantations in this association can contribute to wildlife forage while not seriously

impacting reforestation efforts.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 193

Jeffrey Pine-Red Fir Association

Pinus jeffreyii-Abies magnifica

PIJE-ABMA

CPJCPJ11

Sample size: 8

Distribution

The Jeffrey pine-red fir plant association is primarily an eastside plant

community. It was sampled on the Inyo National Forest and the Lake Tahoe

Basin Management Unit, but it occurs at all latitudes on the eastside. The most

southerly stand sampled was near Casa Vieja Meadows on the Kern Plateau. The

most northerly stand occurred near Emerald Bay in Lake Tahoe. Stands can be

somewhat extensive, but they lie in the range of 10 to 50 acres in most cases.

Environment

This association occurs at high elevations reflecting locations on the eastside.

Stands occur at the highest elevations of all the Jeffrey pine dominated

communities. They are typically located above 8,500 feet. The lowest stand

sampled was on the Lake Tahoe Basin Management Unit at 7,340 feet although

the highest was at 9,520 feet on the Kern Plateau. Aspects typically face southeast

through southwest on slopes that commonly exceed 35 percent. With this

combination of aspect and slope, SRI levels are frequently high. These stands

characteristically occupy upper and middle slope positions. They have

significantly more bare ground than dense forested types such as the red fir or

red fir-white fir associations. Microrelief is variable; some locations are broken

and hummocky, and others are quite uniform.
194 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,607 7,340-9,120

Slope (pct.) 33 12-47

Solar radiation index 0.509 0.386-0.576

Bare ground (pct.) 10 0-43

Surface gravel (pct.) 11 1-35

Surface rock (pct.) 5 0-24

Litter (pct.) 76 39-96

Litter depth (inches) 1.5 0.2-2.2

Stress index 0.52 0.46-0.58

Aspect: SE, SW.

Range: NE, SE, SW.

Position: Upper slopes.

Range: Upper, middle, and lower slopes.

Vegetation

Stands are somewhat open forests with sparse understories composed of

scattered shrub, forb, and grass patches. The overstory is characterized by the

presence of Jeffrey pine. Red fir is generally present as well, but it sometimes

occurs in the middle and lower layers of the tree canopy. Lodgepole pine is an

infrequent component of the species composition. Red fir is often a moist to

mesic site indicator, but Jeffrey pine in most of these stands indicates the

somewhat drier conditions that prevail.

A shrub layer occurs at very low levels on most sites; however, in the southern

portion of the range stands can be dominated by Sierra chinquapin, a dry site

indicator. In the north, sagebrush, bitter brush, and sticky-leaved rabbit brush are

present reflecting dry to moderate eastside conditions. Broad seeded rock cress

and naked stemmed eriogonum in the forb layer and western needlegrass in the

grass layer are all indicators of drier habitats. The overall mix of species in each life

form of this association are indicative of moderate to dry conditions.

Conifer regeneration is among the lowest of any sites in the upper montane.

The average number of seedlings per acre is 85, but distributions are skewed and

the median value is only 15. Stands typically have less than 100 seedlings per

acre. Red fir is usually present, but Jeffrey pine is only present on occasional

sites. When both species are present, red fir occurs in somewhat higher

proportions, but neither species is dominating the sparse regeneration layer.

Plant species diversity is among the lowest of all associations in the upper

montane. These communities have few species overall. Even though they are

somewhat open sites, stands are dominated by two tree species that far outweigh

the cover values of the shrub, forb, and grass layers. Abundant species are few in

number and concentrated in the tree layer.

The oldest trees in these stands are commonly older than 250 years. Although

stands are not substantially older than others in these forests, Jeffrey pine, as a

species, can attain a considerable age. Often, it is older than most other species

when it occurs in combination with other species in these late seral stands, and

the older ages attained by many stands appear to lie in the greater ages attained

by Jeffrey pine. The oldest tree sampled in this association, however, was a red

fir at +409 years, and the oldest Jeffrey pine sampled was +392 years.

Stand replacing disturbances are probably not frequent in this association.

Southerly aspects, steeper slopes, and upper slope positions favor larger, more
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 195

intense fires. On the other hand, these factors are moderated by higher elevations,

lower stand densities, large fire resistant individuals, open understories, and

landscape fragmentation. Evidence from the field during sampling indicates low

occurrence of fire in this association, and stand structures indicate smaller fires as a

normal pattern. Stands in this association probably experience patchy burns with

some portions of the stand completely consumed and others left with little damage.

Disturbance elements such as windthrow and avalanche are not common

features of these stands. Insects, diseases, and lightning are more common, but

they generally occur in localized situations or on select species and seldom

involve replacement of a stand. In most cases disturbance is occurring

continuously on various scales, and this results in the creation of various sized

gaps with constantly changing structures through time.

Reproductive strategies such as consistent seed production, widespread

dispersal of seed, germination on mineral seedbeds, sprouting, or delayed

germination of seed until scarified by fire is present in some species on these

sites. Jeffrey pine is a consistent seed producer that does well on mineral seedbeds

while Sierra chinquapin and bitterbrush are sprouting species.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. After disturbance, stands may go

through a period in a grass/forb phase, and it appears conifer establishment is a

process that can occupy a considerable period of time. Eventually, however,

conifer regeneration becomes established in openings. These trees grow, self

thin, and mature while other portions of the stand undergo disturbance. As

crowns close and tree cover increases, shade tolerant species such as red fir

become established. These species continue to seed in and grow, and without

further disturbance, they can dominate the overstory. Generally, however,

disturbance occurs before the stand is dominated by fir, and Jeffrey pine

reestablishes its position in the stand. In time, a patchy distribution of trees

emerges with several size and tree classes, including a substantial portion of

larger trees. Eventually the stand exhibits an irregular structure with relatively

even-aged patches and large individuals scattered throughout. As stands occupy

sites for longer periods, successive disturbances maintain these stand structures

until an infrequent stand replacing event occurs and a new stand emerges.

 Cover (percent) Mean Range

Total vegetative 72 18-98

Tree 54 17-83

Shrub 10 0-50

Forb 19 1-83

Grass 5 0-30

Moss 0 0

Stand age (years) 270 90-390

Diversity index

Simpson 0.43 0.29-0.91

Hill numbers

N0 7.2 2.0-14.0

N1 3.15 1.21-4.13

N2 2.59 1.10-3.44
196 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

PIJE Jeffrey pine 100 26 4-73

ABMA Red fir 100 30 9-79

II. Understory trees

ABMA Red fir 50 1 1-2

PIJE Jeffrey pine 38 2 1-3

III. Shrubs

CASE3 Sierra chinquapin 25 26 25-26

PUTR Bitter brush 25 1 1-1

IV. Forbs

ARPL Broad seeded rock cress 88 1 1-4

ERNUD Naked stemmed 62 2 1-3

 eriogonum

APMEF Western dogbane 25 1 1-1

V. Grasses and grass-like

STOC1 Western needlegrass 38 1 1-2

STEL1 Elmer’s needlegrass 25 3 3-30

Soils

Soils in this association are Entisols. Most are Psamments indicative of sandy

soils, and the remainder are Orthents. Particle size classes are usually sandy, and

the association has a significantly higher proportion of sites with sandy particle

size classes compared to most others in the upper montane. Occasional samples

from the eastside near Mammoth Mountain are cindery. Soils in these stands are

derived from two parent materials. A portion occur on granitic substrates, and

an equal portion are derived from tephra deposits. These soils differ substantially

from most other sites in that they are commonly formed from alluvial deposits

and less often from bedrock.

Soils are characteristically deep. The majority of sites had soil depths that

exceeded 40 inches, and only one sample had a soil depth of less than 25 inches. On

the other hand, these soils are coarse textured. Textures in both the topsoil and

subsoil are essentially gravelly sands. This association differs from many others in

containing significantly higher levels of gravels in the topsoil. Coarse fragments

are also significantly higher throughout the profile than most other sites. Topsoil

coarse fragments, for example, are often greater than 35 percent, and occasionally

they are greater than 65 percent. Subsoil coarse fragments commonly range

between 15 and 35 percent, but they occasionally exceed 65 percent as well. Topsoil

colors are typically 10 YR in hue and mollic in chroma and value although a

significantly high portion were ochric. Such soils are light yellowish brown. Subsoil

colors are also 10 YR in hue, but they have a significantly higher proportion that

are high value compared to most other sites. Colors on such sites range from light

brownish gray to brownish yellow when moist.

The AWC of these sites is wide ranging. The average AWC is among the

lowest in the upper montane forests although there is substantial variation in

values and this may not be true on specific sites. Bedrock contacts are commonly

unfractured and unrootable, and drainage is frequently excessive. Subsoil pH is

considerably more neutral than on most other sites. These soils are warm.

Summertime temperatures commonly exceed 58o

 Fahrenheit.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 197

 Variable Mean Range

Depth of soil sample (inches) 38 17-40+

Topsoil

Depth (inches) 9 4-16

Coarse fragments (pct.) 36 6-80

pH 5.9 4.8-6.5

Subsoil

Coarse fragments (pct.) 36 5-85

pH 6.1 5.5-6.7

AWC (inches) 2.2 0.5-3.9

Temp (20 inches) (Fahrenheit) 56 40-64

Productivity

Site indexes are moderate. Pacific Southwest Region (Region 5) site indexes

are usually 3. None were encountered that were less than 3 nor higher than 2.

Stand density is also moderate. Stand density indexes are commonly greater

than 300, but few exceed 500. They are substantially less than stocking levels

attained in the densest stands such as those in the red fir-white fir association,

but commonly they will attain stocking levels that are more than 60 percent of

those values, and occasionally values will reach more than 95 percent. Stocking

in these late seral stands also resides in the larger individuals of the stand.

Average quadratic mean diameters approach those of typical red fir stands that

carry much of their stocking in larger size trees. Tree heights reflect the moderate

site indexes experienced on these sites. The tallest red fir measured 162 feet, and

the tallest Jeffrey pine measured 143 feet in this association. Moderate site

indexes and stocking levels results in moderate cubic and board foot yields for

these stands.

Stand structures are irregular; however, more than most other stands in the

upper montane, they tend to approach an even-aged or two storied distribution

in this association (fig. 34). Trees larger than 24 inches are distributed almost

evenly by size class, and trees smaller than 24 inches are present in substantially

fewer numbers than in other associations, giving a relatively uniform distribution

across all size classes. Compared to the balanced diameter distribution of an

uneven-age stand with similar stocking levels, trees in size classes up to 24

inches are substantially fewer in number, and those in size classes above 30

inches are somewhat over-represented. When compared to a balanced even-age

distribution, trees in size classes less than 24 inches and larger than 30 inches are

higher in number than needed at similar stocking levels.

 Variable Mean Range

Region 5 site index 3 2-3

Forest survey site class 4 3-4

Stand density index 324 92-647

Quadratic mean diameter 23.7 13.1-40.9

Softwood volume (mcf/ac) 8.0 3.4-12.8

Softwood volume (mbf/ac) 49.8 21.4-91.4

Softwood basal area (sq ft/ac) 234 88-413

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
198 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 46 - - 53 1 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag densities are moderate to high. Most mortality occurred in size classes

below 18 inches in diameter. This concentration appears to result primarily

from self thinning as stands develop. Mortality is distributed evenly among

species. Snag heights are concentrated in the 20 to 50 foot class reflecting the

higher numbers of smaller size snags. Decay classes generally lie between 1 and

3. Logs from the samples were all less than 30 inches in large end diameter, and

the majority were less than 50 feet in length. Log decay classes also differed

from most other associations in containing an unusually high number between

classes 1 and 3.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 15.8 2.8 2.0 1.7 0.5 0.3 23.1

Snag height (feet)

<20 4.7 0.7 0.8 0.8 0.2 0.1 7.3

20-50 9.5 0.7 0.4 0.9 0.1 - 11.6

>50 1.6 1.4 0.8 - 0.2 0.2 4.2

Snag decay class

1 3.2 1.4 - - - - 4.6

2 6.3 - 2.0 - 0.2 0.1 8.6

3 6.3 1.4 - 1.7 0.2 0.2 9.8

4 - - - - - --

5 - - - - 0.1 - 0.1

Figure 34—Number of trees by

diameter class in the Jeffrey pine-red

fir plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

30

40

50

60
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 199

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 16.0 8.0 0 0 24.0

Log length (feet)

<20 12.0 4.0 - - 16.0

20-50 4.0 2.0 - - 6.0

51-100 - 2.0 - - 2.0

>100 - ----

Log decay class

1 4.0 - - - 4.0

2 6.0 6.0 - - 12.0

3 2.0 2.0 - - 4.0

4 4.0 - - - 4.0

5 -----

Wildlife

Stands appear to offer marginal forage possibilities for large game. Bitter brush is

a preferred forage species, but it occurs somewhat infrequently and with low

cover. Naked stemmed eriogonum in the forb layer, and western needlegrass are

staples in the large game diet that may provide some contribution to the large

game diet. Deer use was observed to be uncommon, although a majority of sites

had pocket gophers present.

Range

These are transitional range sites that are used by livestock to access primary

sites such as meadows and other moist habitats. Evidence of cattle presence

was observed on all sample sites in this association. Although most of the

shrub component contains low value forage, bitter brush is a secondary forage

species; however, constancy and cover values are low. Western needlegrass is a

secondary range species in the grass layer. It occurs with sufficient frequency,

but cover values are also low. It appears range forage potential is low in these

late seral stands.

Management Recommendations

Some harvesting has taken place in this association. Most harvests have been

in the form of improvement or salvage cutting, but in some cases clearcutting

was practiced to create even-aged stands. Site preparation appears to have

been marginal, planting was uncertain, and poor conifer establishment has

resulted. The reasons for failure are unclear. Early successional sequences are

poorly understood, and they have not been investigated closely at this time.

On most sites, neither red fir nor Jeffrey pine seem to be naturally regenerating

these stands. Until more experience is gained, caution should be exercised in

treating these stands, and prolonged periods to achieve acceptable stocking

should be expected.

These stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable. Recommendations for harvesting

can involve both even- and uneven-aged siliv cultural systems and a variety of

cutting methods, but the ability of sites to respond to treatment is uncertain,
200 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

and the ability to predict results of treatment are not based on wide experience

or research results at this time. The open nature of these stands indicates that

regeneration and establishment is a lengthy and variable process under most

conditions. Openings for regeneration should be kept small, probably less than

5 acres. A regeneration strategy recommended at this time would involve site

preparation to prepare a mineral seedbed to encourage natural seeding,

followed by planting with both Jeffrey pine and red fir as preferred species for

early stocking of these sites. Future treatments should emphasize continued

development of this species mix.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 201

Lodgepole Pine/Sagebrush Association

Pinus contorta/Artemesia tridentata

PICO/ARTR

CPLCPL14

Sample size: 11

Distribution

The lodgepole pine/sagebrush plant association is predominantly an eastside

plant community occurring at middle to upper elevations near the Sierra Nevada

crest. It was sampled primarily on the eastside, but a few stands were located just

west of the crest on westside forests. The association spans the full range of

latitudes in the central and southern Sierra Nevada, but longitudes reflect the

eastern setting of most samples. Along with the lodgepole pine and red fir-western

white pine-lodgepole pine associations, these are the stands in the upper montane

forest that transition into subalpine vegetation at still higher elevations. Stands

can often cover extensive areas, but usually they are less than 50 acres due to

natural patchiness of the landscape.

Environment

Elevations typically lie above 8,500 feet. The lowest stand sampled was at 7,560 feet

on the Toiyabe National Forest, and the highest was in the Inyo National Forest at the

southern limit of the upper montane on the Kern Plateau. Southeast and southwest

aspects are common, but occasional northwest facing slopes are also encountered.

Stands are often located on moderate slopes between 20 and 30 percent. They

commonly occur on middle to lower slopes, but a high proportion are also found on

upper slopes and broad ridge top locations. Microrelief is frequently uniform and

relatively smooth. This association has substantially higher levels of surface gravel

and shallower litter depth compared to most other sites in the upper montane.
202 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

 Variable Mean Range

Elevation (feet) 8,510 7,560-9,480

Slope (pct.) 22 11-40

Solar radiation index 0.505 0.380-0.552

Bare ground (pct.) 10 2-25

Surface gravel (pct.) 13 2-30

Surface rock (pct.) 3 0-20

Litter (pct.) 74 48-86

Litter depth (inches) 0.6 0.2-1.0

Stress index 0.48 0.39-.59

Aspect: SE, SW.

Range: SE, SW, NW.

Position: Middle and lower slopes.

Range: Upper, middle, lower slopes, toeslopes.

Vegetation

Stands are open woodlands with a shrubby understory of sagebrush. Tree cover

is low compared to many other sites in these forests, and trees tend to occur as

scattered clumps and individuals. Sites are generally dominated by lodgepole

pine. Red fir is often present as a member of the stand, but in most cases

lodgepole pine is the only component of the overstory, and red fir occurs as

scattered individuals in the understory. Other species such as western white

pine, and Jeffrey pine are present in rare instances. These sites are often

interspersed with western juniper/sagebrush and quaking aspen/mountain

pennyroyal associations and sagebrush shrublands at the edge of the Great

Basin. They usually lie adjacent to denser forested stands of the red fir-western

white pine-lodgepole pine and lodgepole pine associations.

Understories are characterized by an open shrub layer dominated by

sagebrush. Forb cover is among the highest in the upper montane, and both the

shrub and forb layers are substantially higher than most other associations. The

open growth habit of sagebrush in these forests moderates cover values, and as

are sult, total vegetative cover is not much different from many other stands.

Sagebrush generally indicates the moderate to dry conditions occurring on these

sites. Squaw currant and mountain snowberry are usual members of the shrub

component. They also indicate the moderate to drier conditions that prevail. The

forb layer is composed of a mix of species which, in general, reflect moderate to

dry conditions. Thus, broad-seeded rock cress, mountain pennyroyal, Sierra

wallflower, and Coville’s gayophytum generally inhabit drier sites, and

mountain mule-ears and Kellogg’s bedstraw occur on sites with moderate

conditions. Mountain sweet cicely and Fendler’s meadow rue tend to occupy

moist sites. In the grass layer bottle-brush squirreltail and western needlegrass

favor dry sites, and Ross’ sedge is often indicative of dry to moderate habitats.

Conifer regeneration is moderate to low. Although the average is 513 seedlings

per acre there is considerable variation between sites, and individual stands typically

carry fewer than 250 seedlings per acre. Median values are only 80 per acre. Red fir

and lodgepole pine are generally present , but red fir dominates this layer when it

occurs. Western white pine, Jeffrey pine, and very rarely western juniper, are also

present, but they occur in greatly reduced numbers. Lodgepole pine is regenerating

significantly more often compared to other associations in the upper montane.

Plant species diversity is among the highest in these forests. It has only a few less

species on average than the quaking aspen/mountain pennyroyal and western

juniper/sagebrush associations. Lower tree cover in conjunction with higher cover

of shrubs, forbs, and grass species result in relatively uniform distributions among

high numbers of abundant species. Vegetative cover is spread somewhat uniformly

among species of several life forms.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 203

The oldest trees in these stands are typically older than 250 years. This

includes the lodgepole pine, which although smaller in diameter, is not

substantially different in age from other conifers in these forests. These stands

are comparable in age to other upper montane associations. The oldest trees

sampled were a lodgepole pine at +303 years and a red fir at +282 years.

Stand replacing events may occur in this association at somewhat higher

frequencies than others in the upper montane. Shrubby sites on drier southerly

aspects with irregular tree distributions would indicate a different fire regime

than many others in these forests, and these factors would certainly favor larger,

more intense fires. Conversely, the structure of stands with widely spaced

individuals and the non-continuous distribution of the shrub layer would tend

to ensure some level of tree survival after a fire. These stands probably experience

patchy burns with portions of stands being completely consumed and others left

with little damage. Isolated large and small trees probably escape damage in

most cases. Disturbance elements such as windthrow, insects, disease, lightning,

or avalanche are often localized or affect select species, and they do not appear to

result in large scale stand replacement in the upper montane.

Reproductive strategies such as consistent seed production, widespread

seed dispersal, germination on mineral soil, sprouting, or delayed germination

of seed until scarified by fire are present in many of the species on these sites.

Lodgepole pine is a consistent seed producer that does well on mineral seedbeds.

Sagebrush burns readily, but it is a non-sprouter that may lose dominance on

sites for as long as 50+ years after fire. It may actually indicate sites that have not

experienced a recent fire. Future occupancy of these sites by sagebrush is

uncertain for periods of 50+ years, and they will probably change into persistent

forb and grass dominated communities in the understory. The patchiness of

vegetation and the wide spacing of existing trees would result in uneven coverage

of sites by many disturbance elements. In most cases the species composition of

future stands is determined by species currently on these sites.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. Disturbance creates opportunities

for conifer regeneration, but early succession on these sites may involve a

persistent grass phase, and in most cases it appears conifer establishment can

occupy a considerable period of time. Disturbance also provides opportunities

for surviving individuals to increase growth. Isolated patches of conifers

probably escape many disturbances and proceed through periods of crown

closure and self thinning. Isolated trees and small patches that escape repeated

disturbance eventually mature into larger members of the stand. In time, the

stand develops an irregular structure reflecting numerous disturbances, and

containing large trees that are the survivors of several stand altering events.

Cover (percent) Mean Range

Total vegetative 83 70-99

Tree 44 18-68

Shrub 26 3-52

Forb 37 2-70

Grass 25 4-75

Moss 0.1 0-1

Stand age (years) 176 95-300

Diversity index

Simpson 0.21 0.10-0.36

Hill numbers

N0 17.7 9.0-28.0

N1 7.83 4.07-13.47

N2 5.79 2.80-10.10
204 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

PICO Lodgepole pine 100 31 10-57

ABMA Red fir 54 21 8-34

II. Understory trees

PICO Lodgepole pine 64 1 1-1

ABMA Red fir 64 4 1-17

PIJE Jeffrey pine 27 1 1-1

III. Shrubs

ARTR Sagebrush 91 18 1-50

RICE Squaw currant 64 3 1-11

SYVA Mountain snowberry 45 4 2-6

PUTR Bitter brush 36 1 1-2

SYPA Parish’s snowberry 36 2 1-5

CHVI4 Sticky leaved rabbit brush 27 1 1-2

IV. Forbs

ARPL Broad seeded rock cress 73 3 1-15

MOOD Mountain pennyroyal 64 6 1-15

PESE3 Pine-woods lousewort 64 1 1-1

ERPE3 Sierra wallflower 55 2 1-5

CAAP Indian paint brush 45 1 1-1

WYMO Mountain mule ears 45 17 1-33

ERSP2 Spurry eriogonum 36 2 1-5

GAER Coville’s gayophytum 36 2 1-5

CHBR3 Brewer’s golden aster 27 9 1-18

CIAN1 Anderson’s thistle 27 3 1-6

COTOW Wright’s blue eyed mary 27 13 3-30

HACA1 California stickseed 27 2 1-3

HAJE Jessica’s stickseed 27 1 1-2

KEGA Kellogg’s bedstraw 27 1 1-2

OSCH Mountain sweet cicely 27 1 1-1

SIGL Glaucous sidalcea 27 7 1-30

THFE Fendler’s meadow rue 27 9 1-25

V. Grasses and grass-like

SIHY Bottle brush squirreltail 82 5 1-15

CARO1 Ross’ sedge 45 4 1-10

MEBU1 Western oniongrass 36 2 1-5

STOC1 Western needlegrass 36 3 1-10

STCA1 California needlegrass 27 2 1-3

Soils

Usual soils are Inceptisols, but occasional and significantly higher levels of

Alfisols are also encountered. Entisols and Mollisols seldom occur. The majority

of Inceptisols are Umbrepts with occasional Ochrepts. Alfisols are commonly

Xeralfs with a few Boralfs. Particle size classes are distributed between skeletal

and loamy, with skeletal soils usually occurring more often and reflecting the

higher levels of coarse fragments throughout the profiles. Parent materials are

also somewhat varied. Normally, these soils are derived from volcanic substrates

such as the andesitic and rhyolitic flow rocks and lahars of the northern portion

of the study area, but some are derived from granitic parent materials, and it is

suspected that overall in the range, granitic parent materials constitute a
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 205

substantial part of the bedrock formations under this association. Soils are usually

weathered in place from bedrock; however, some are formed in deposited

materials such as glacial till, alluvial, and colluvial deposits.

These soils are generally deep. Samples were generally deeper than 35

inches, and rarely were they less. Average topsoil depths are also quite deep;

they are among some of the deepest in the upper montane forested plant

communities, and they are significantly deeper than most other sites. Topsoil

textures are usually loams with some gravelly sandy loams. Subsoil textures

tend to be more variable. Here sandy loams are encountered more often, and

loams are less common. Textures are also more gravelly. Sands, sandy clay

loams, and clay loams were also encountered in a few cases in the subsoils.

Topsoil coarse fragments also tend to be high. They are substantially higher than

soils in most other associations in the study area. Generally, coarse fragments

exceeded 15 percent, and sites with greater than 35 percent coarse fragments in

the topsoil were not uncommon. Soil colors in both the topsoil and subsoil are

essentially 10 YR in hue. Subsoil colors, however, have significantly higher

proportions of high values compared to most other sites in the upper montane.

Such soils are basically lighter; most range from light brownish gray to brownish

yellow when moist.

The AWC of these sites ranges considerably; however, they are not

substantially different from most other sites. Most can be considered to be

moderately high, and they reflect the combination of deeper soils with finer

textures. Bedrock formations below the soil profile are generally fractured and

rootable providing additional sources of water to these stands. Typical sites are

well drained, and erodibility is moderate to high as a result of the finer textured

surface horizons and somewhat steeper slopes. Even though stands lie at

somewhat higher elevations, summertime soil temperatures are warm reflecting

the more open stand conditions and southerly aspects. They are significantly

warmer than most other associations with dense tree cover, and temperatures

commonly exceed 53

o

 Fahrenheit.

 Variable Mean Range

Depth of soil sample (inches) 37 26-40+

Topsoil

Depth (inches) 12 8-20

Coarse frag. (pct.) 30 10-75

pH 5.9 5.3-6.5

Subsoil

Coarse frag. (pct.) 38 15-55

pH 5.9 5.2-7.1

AWC (inches) 3.3 1.9-4.6

Temp (20 inches) (Fahrenheit) 55 42-62

Productivity

Site indexes are moderate to low. In the majority of stands, Pacific Southwest

Region (Region 5) site indexes are 3 or poorer. Most frequently they are 3 and 4.

Stand densities are also quite low. Stand density indexes are characteristically

less than 300. Based on average stand density indexes, these sites carry 40

percent of the stocking that can be carried by the red fir-white fir plant

association, which is one of the densest in the upper montane. Tree heights are

also substantially shorter than those in many other forested associations. This

reflects both lower site indexes and the presence of lodgepole pine. The tallest

tree was a red fir which measured 153 feet compared to the tallest lodgepole pine

measured at 103 feet. Stocking is concentrated in the larger individuals of the

stand. Quadratic mean diameters for stands in the association indicate the
206 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

presence of relatively large trees. They compare reasonably well with forested

stands of the red fir association that retains high stocking levels in larger trees.

The largest lodgepole pine was measured at 43 inches. The combination of

moderate site indexes and shorter trees in relatively open stands results in cubic

and board foot yields that are among the lowest in the upper montane and less

than 30 percent of stands in associations such as red fir or red fir-white fir.

Stand structures in late seral stands are irregular. These are open stands with

low numbers of trees per acre, and individual stand structures appear variable.

When examined collectively, the distribution of stems overall approximates that

of an uneven-aged structure to a large degree (fig. 35). Considering the low

stocking levels of these stands, they fit an uneven-aged distribution quite well.

When compared to uneven-aged structures in stands with similar stocking and

balanced diameter distributions, they generally carry appropriate numbers of

trees in all size classes below 40 inches and excess trees only in regeneration.

Compared to the normal distribution of an even-aged stand, there are far too

many trees in size classes below 24 inches and more trees in size classes larger

than approximately 30 inches than would be appropriate. The largest portion of

trees in all size classes is lodgepole pine. Red fir dominates only the regeneration

layer and the largest size classes.

Variable Mean Range

Region 5 site index 4 2-5

Forest survey site class 5 3-6

Stand density index 225 99-429

Quadratic mean diameter 21.7 10.6-35.5

Softwood volume (mcf/ac) 4.3 1.5-9.8

Softwood volume (mbf/ac) 25.7 8.1-68.2

Softwood basal area (sq ft/ac) 154 56-240

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Figure 35—Number of trees by

diameter class in the lodgepole pine/

sagebrush plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

10

20

30

40

50

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 33 - 54 8 1 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent 4 - - - - -
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 207

Coarse Woody Debris

Snag numbers are low indicating the open conditions of this association. snags

are apparently concentrated in the larger size classes, but this may be reflective

of a low number of sample snags in these open stands. Mortality occurs randomly

among species on these sites. Logs are characteristically less than 30 inches in

large end diameter and less than 50 feet in length. Logs are distributed among all

decay classes, but most occur in classes 4 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0 0 0 0 0.3 0.3

Snag height (feet)

<20 - - - - - 0.3 0.3

20-50 - - - - - - -

>50 - - - - - - -

Snag decay class

1 - - - - - --

2 - - - - - --

3 - - - - - --

4 - - - - - --

5 - - - - - 0.3 0.3

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 3.0 4.0 0.5 1.0 8.5

Log length (feet)

<20 2.0 2.5 0.5 0.5 5.5

20-50 1.0 1.0 - - 2.0

51-100 - 0.5 - 0.5 1.0

>100 - ----

Log decay class

1 0.5 0.5 - - 1.0

2 0.5 - - - 0.5

3 - 0.5 - 0.5 1.0

4 2.0 0.5 - - 2.5

5 - 2.5 0.5 0.5 3.5

Wildlife

Forage values appear moderate to high for large game. Several species in this

association are preferred and staple species in the large game diet. Thus,

mountain snowberry and bitterbrush are preferred species in the shrub layer,

and sagebrush is a staple. In the forb and grass layers, Indian paint brush,

spurry eriogonum, bottle brush squirreltail, Ross’ sedge, western oniongrass,

and western needlegrass are all staples. They occur with enough frequency and
208 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

cover to be reasonable sources of food. Surprisingly, evidence of deer and

pocket gophers on these open sites was uncommon.

Range

Range potential appears to be transitory as livestock move to primary range sites

in meadows or other moist habitats. Bitter brush and mountain snowberry are

secondary forage species in the shrub component. In the grass layer California

needlegrass is a primary species, and bottle brush squirreltail and western

needlegrass are secondary species. The moderate levels of occurrence and cover

of these species would appear to contribute to their potential as range sites.

Evidence of cattle use was observed on these sites but at surprisingly lower

levels than in other associations that appear to be less desirable for range forage.

Management Recommendations

Few stands in this association have been harvested. These have occurred

primarily on the eastside as salvage and improvement cuttings. Formal

silvicultural systems have apparently not been applied although varied stand

structures are present. Establishment of natural regeneration is uncertain.

Successional sequences are not well understood, but high levels of shrub

competition would seem to be a factor in regeneration success. This association

occupies large areas along the crest. It is felt they will continue to be dominated

by lodgepole pine.

This is one of the more diverse plant associations in the upper montane

forests, and it provides an important contribution to landscape diversity.

Harvesting in these stands at the present time should be conducted with caution.

Results from the application of formal silvicultural systems are uncertain at

present. Limited opportunities exist for salvage when it occurs, but on these

open sites management should emphasize existing wildlife habitat in

combination with plant species richness and landscape level diversity.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 209

Lodgepole Pine/Gray’s Lovage Association

Pinus contorta/Ligusticum Grayii

PICO/LIGR1

CPLCPL11

Sample size: 23

Distribution

The lodgepole pine/Gray’s lovage plant association is widespread in the Sierra

Nevada. Latitudes and longitudes span the range of the study area, and it was

sampled in every National Forest and Park in the study area except for the

Toiyabe. This association generally occurs on moister sites, and stands often

cover extensive areas bordering drainage bottoms and adjacent to meadows.

Stands are often narrow; usually they are smaller than 10 acres, and in some

cases, they can be less than an acre.

Environment

Lodgepole pine has a wide elevational distribution in the Sierra Nevada. Both

the lowest and some of the highest elevations for this association occurred in the

north reflecting this distribution. Aspects are varied, but frequently northeast

and northwest facing slopes are encountered. The average SRI is among the

lowest in the upper montane. Slopes are quite shallow, and stands

characteristically occupy lower slope positions. Typical locations are adjacent to

flat areas such as meadows, on toeslopes, or in gently undulating terrain where

slope angles are typically less than 10 percent. Benches and shallow drainages

higher on slopes are frequent locations. Microrelief on many sites is hummocky

and broken reflecting the presence of small scale drainage patterns that often

dissect these communities. This association has considerably less surface gravel

than most others in the upper montane. There is abundant moisture available to

these sites, and stress indexes are among the lowest of all forested sites in the

upper montane.
210 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Variable Mean Range

Elevation (feet) 7,973 6,660-8,920

Slope (pct.) 11 3-32

Solar radiation index 0.487 0.438-0.561

Bare ground (pct.) 1 0-4

Surface gravel (pct.) 1 0-6

Surface rock (pct.) 4 0-25

Litter (pct.) 91 61-99

Litter depth (inches) 1.4 0.4-2.4

Stress index 0.43 0.28-.56

Aspect: NE,NW.

Range: All.

Position: Lower slopes, benches.

Range: All.

Vegetation

Stands are dense forests with a rich understory of forbs. Along with stands in the

quaking aspen series, this association has the highest average total vegetative

cover of any in the upper montane. Tree, forb, and grass cover are all substantially

higher than most other associations, and moss occurs significantly more often in

these stands. The overstory is dominated by lodgepole pine, but red fir is usually

present as well. These are moderate to moist site species that indicate the basically

moist conditions within stands. In some stands lodgepole pine or red fir may be

the only member of the overstory, but the characteristically dense understory of

forbs and grass aids in identifying the association. Stands often lie adjacent to the

red fir-lodgepole pine/white-flowered hawkweed association.

Understory vegetation, particularly in the forb and grass component, can be

quite lush. Sierra gooseberry and alpine prickly currant are moist site indicators

that are present as occasional shrubs, and a large assemblage of forbs such as

Gray’s lovage, serrated wintergreen, Parish’s yampa, arrowhead butterweed,

mountain sweet cicely and California corn lily are usually present as indicators

of moist conditions. Finally, Bolander’s bluegrass, and common woodrush are

mesic to moist site indicators in the grass layer that are typically present.

Important variations of the forb species occupying these sites occur in the south

and on the eastside. In these locations, the more typical members of the

association such as Gray’s lovage and Parish’s yampa are not as common or

simply do not occur. In most of these situations, serrated wintergreen is present,

but where it is missing arrowhead butterweed, broad petaled strawberry or

clover can often be used to identify the association.

Conifer regeneration is high in these stands. Late seral stands average 1,340

seedlings per acre, and they typically carry more than 500 per acre. Both red fir

and lodgepole pine are generally present, but the number of lodgepole pine

seedlings is often less than one-third that of red fir. Both species are regenerating

in significantly higher frequencies than in other associations.

Plant species diversity is moderately high for upper montane forests. The

total number of species is moderate, and diversity is influenced by the relatively

high number of forb species. Stands compare with associations such as quaking

aspen/California corn lily, the Jeffrey pine/mountain whitethorn, and red fir/

mountain mule ears as far as total number of species present; however, abundant

species are concentrated in a relatively few tree species which dominate the

cover in these stands.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 211

The oldest trees in these stands are typically greater than 150 years. Average

stand ages are significantly younger than most other forested stands in the upper

montane. This results from high numbers of younger trees in smaller size classes.

Scattered throughout most stands are predominant lodgepole pine and red fir

that are as old as those in the upper montane in general. The oldest tree sampled

in this association, for example, was a lodgepole pine at ±354 years, and the

oldest red fir sampled was ±202 years.

Stand replacing disturbance events probably occur in this association, but

they do not appear to be frequent or large scale phenomenon. The location of

many stands along cooler drainage bottoms, the gentle topography of most sites,

the structure of the stands with abundant herbaceous understories, and the

presence of relatively large, somewhat fire resistant individuals results in uneven

coverage by fire. These features tend to preclude fire caused stand replacement.

Other disturbance elements such as windthrow, insects, disease, lightning, or

avalanche also do not appear to affect large areas in these stands. It is likely that

disturbance from several elements occur continuously on various scales, and this

results in the creation of various sized gaps with constantly changing structures

through time.

Reproductive strategies such as reasonably constant seed production is

present in most of the tree species on these sites. Lodgepole pine is a prolific

seeder with rapid early height growth, but red fir is shade tolerant, and it can

assume dominance as stands develop. Lodgepole pine is shade intolerant, but it

can be maintained by disturbances that open stands and provide seed beds. In

most cases the species composition of future stands is largely determined by

species presently on these sites.

After disturbance it does not appear that these stands go through a prolonged

period in a shrub phase during early succession; however, a forb/grass phase

can often persist for long periods. Lodgepole pine can occupy grass dominated

communities such as those in meadows. Once regeneration is established, it

grows, self thins, and matures, but other portions of the stand continue to

undergo disturbance. As tree cover increases, shade tolerant species such as red

and white fir become established. These species continue to seed in and grow in

height until they overtop the lodgepole pine. In time, and without further

disturbance, they can dominate the overstory. Generally, however, disturbance

will occur before the stand is dominated by fir, and this will allow an increase in

the lodgepole component. In time, several size classes, including a substantial

portion of larger trees, are represented, and the stand exhibits an irregular

structure with many small relatively even-aged patches. As stands occupy sites

for longer periods, multiple disturbances continue to be important in maintaining

structures and species composition until an infrequent stand replacing

disturbance occurs, and a new stand emerges.

Cover (percent) Mean Range

Total vegetative 94 82-99

Tree 76 61-95

Shrub 4 0-30

Forb 43 1-99

Grass 17 2-45

Moss 4 0-35

Stand age (years) 172 76-336

Diversity index

Simpson 0.35 0.14-0.65
212 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Hill numbers

N0 14.1 7.0-22.0

N1 4.99 2.43-10.20

N2 3.41 1.54-7.25

Characteristic Vegetation

Percent cover

Code Common name Constancy Mean Range

I. Overstory trees

PICO Lodgepole pine 100 55 13-89

ABMA Red fir 61 33 4-72

II. Understory trees

PICO Lodgepole pine 83 1 1-5

ABMA Red fir 83 6 1-56

ABCO White fir 22 4 1-18

PIMO3 Western white pine 22 1 1-1

III. hrubs

RIMO Alpine prickly currant 30 9 1-30

RIRO Sierra gooseberry 30 2 1-4

IV. Forbs

LIGR1 Gray’s lovage 74 5 1-50

PYSE2 Serrated wintergreen 56 3 1-10

PESE3 Pine woods lousewort 52 1 1-3

PEPA5 Parish’s yampah 43 1 1-6

SETR Arrowhead butterweed 43 2 1-50

ACLA2 Common yarrow 39 5 1-16

ERPEA Wandering daisy 39 5 1-30

HIAL White flowered hawkweed 39 3 1-15

VIPU Mountain violet 35 2 1-6

THFE Fendler’s meadow rue 30 4 1-15

VECA1 California corn lily 30 2 1-5

LULAC Broad leaved lupine 26 8 3-20

OSCH Mountain sweet cicely 26 6 1-20

BRLU2 Yellow brodiaea 22 2 1-4

V. Grasses and grass-like

POBO1 Bolander’s bluegrass 83 2 1-4

CARO1 Ross’ sedge 70 8 1-35

LUCO1 Common woodrush 57 3 1-20

AGTH Thurber’s bent grass 43 2 1-5

Soils

Typical soils in this association are Inceptisols. Entisols, Mollisols, and Alfisols

are encountered in a few cases. The Inceptisols are distributed between

Xerumbrepts and Xerochrepts. Entisols commonly occur as Orthents. Particle

size classes are also somewhat divided between skeletal and loamy, but usually

they are loamy and indicate lower levels of rock fragments in profiles. The

Cover (percent) Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 213

majority of these soils are derived from granitic rocks, and rarely do they occur

on other substrates. Soils in this association are usually weathered in place from

bedrock; however, they occasionally are formed from material that has been

deposited such as glacial till, colluvium, or alluvium.

These soils are moderately deep to deep. Usually they are deeper than 35

inches; some exceed 40 inches, and few are less than 25 inches. Textures in the

topsoil are typically loams with occasional sandy clay loams and sandy loams.

Subsoils are usually loams as well, but they are coarser textured with higher

proportions of sandy loams and sands. Overall, soils in this association are finer

textured than most others in the upper montane. They can be considered medium

to moderately coarse textured soils. Average coarse fragment contents in the

topsoil are among the lowest of any in these forests. Colors in the topsoil are

commonly 10 YR in hue and mollic in value and chroma. Basically these are dark

brown soils when moist; however, topsoil colors show a wider range in hues

than most other sites. Occasional samples had 5 YR and 7.5 YR hues with mollic

value and chroma or 10 YR hues with ochric value and chroma. Subsoil colors are

also considerably more variable in hue than most other sites, and samples with 5

YR, 7.5 YR, and 5 Y hues are sometimes encountered.

The average AWC of these soils is one of the highest in the upper montane. It

reflects the moderately deep soils with finer textures and few topsoil coarse

fragments. A noticeable feature of these stands is the abundance of forbs and

grasses present throughout the season suggesting high water tables. This appears

to be true even in cases where soil depths are shallow or AWC is low. Most sites

lie over parent materials that are massive and unrootable, and although many

sites are well drained, a significantly high proportion are also poorly drained.

This indicates a tendency to retain water in the soil profiles. Lodgepole pine is

known to be tolerant of persistently high water tables and is capable of stocking

sites under these conditions. Erodibility ranges from moderate to high. Shallow

slopes reduce erodibility, but this is often counterbalanced by the high proportion

of loamy soil textures in this association. Summertime soil temperatures are cool.

Average temperatures in this association are the lowest of any in these higher

elevation forests, and they characteristically lie below 49

o

 Fahrenheit.

Variable Mean Range

Depth of soil sample (inches) 35 22-40+

Topsoil

Depth (inches) 9 3-31

Coarse frag. (pct.) 14 1-42

pH 5.6 4.4-6.5

Subsoil

Coarse frag. (pct.) 32 1-86

pH 5.9 4.3-6.7

AWC (inches) 3.8 1.7-5.7

Temp (20 inches) (Fahrenheit) 45 38-54

Productivity

Site indexes are moderate. In the majority of stands, Pacific Southwest Region

(Region 5) site indexes are 2 or 3. Rarely are they better than 2 or less than 3.

Stand densities, on the other hand, are quite high. Stand density indexes

commonly exceed 400 in these stands. Based on average stand density indexes

these sites can hold over 90 percent of the stocking of the red fir-white fir plant

association, which is one of the densest in the upper montane. Tree heights,

however, are substantially shorter than those in other dense forested plant
214 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

associations. This reflects the presence of large numbers of lodgepole pine,

which is generally a shorter tree in the Sierra Nevada. The tallest tree in the

association was actually a lodgepole pine that measured 144 feet compared to the

tallest red fir measured at 132 feet. Quadratic mean diameters are small in

comparison to those in other late seral forested stands and reflect the presence of

many smaller lodgepole pine. The combination of moderate site indexes and

shorter, smaller diameter trees with higher stand densities results in cubic and

board foot yields that are moderate for the upper montane, but about half those

in highly productive associations such as red fir or red fir-white fir.

Individual stands often have the appearance of an even-aged or two storied

structure; however, stands frequently exhibit other structures, and taken

collectively they can be considered irregular. Distributions actually approximate

those of an uneven-aged stand to a large degree (fig. 36). Compared to unevenaged structures in stands with similar stocking and balanced diameter

distributions they tend to carry too many trees in size classes below 30 inches;

however, the number of trees in size classes larger than 30 inches is appropriate

for uneven-aged structures. When these stands are compared to an even-age

structure, there are too many trees in size classes below 24 inches and more trees

in size classes larger than 30 inches than would be appropriate. Lodgepole pine

carries the largest portion of trees in size classes between 6 and 24 inches in most

of these stands, and viewed as a separate component of the stand, distributions

for this species appear even-aged.

Variable Mean Range

Region 5 site index 3 1-5

Forest survey site class 4 2-6

Stand density index 489 223-951

Quadratic mean diameter 17.2 9.1-28.2

Softwood volume (mcf/ac) 8.6 3.0-21.2

Softwood volume (mbf/ac) 47.0 13.1-141.5

Softwood basal area (sq ft/ac) 333 220-600

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Figure 36—Number of trees by

diameter class in the lodgepole pine/

Gray’s lovage plant association.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

20

40

60

80

100

120

140

160
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 215

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 28 - 70 - 2 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Total snag numbers are among the highest in upper montane forests. In particular,

the number of snags with diameters less than 18 inches are substantially higher

than most other sites. Mortality occurring in these size classes is predominantly

lodgepole pine and represents a substantial amount of thinning within sapling

and pole size trees. Most snags are less than 50 feet in height reflecting the

presence of lodgepole pine in the stands. Snags taller than 50 feet are also well

represented and indicate the presence of both red fir and lodgepole pine, which

often topples intact rather than breaking down from above. Snag decay classes

commonly lie between 1 and 2. Logs are typically less than 30 inches in large end

diameter, and usually they are less than 20 feet in length. Logs are more decayed

than snags; most logs lie between decay class 3 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 21.6 9.2 3.1 1.0 1.0 0.6 36.5

Snag height (feet)

<20 10.3 1.4 - 0.1 0.1 0.3 12.2

20-50 0.1 4.6 0.3 0.2 0.3 - 14.5

>50 2.2 3.2 2.8 0.7 0.6 0.3 9.8

Snag decay class

1 8.1 1.7 0.7 0.2 - 0.3 11.0

2 9.2 5.7 1.5 0.4 0.6 - 17.4

3 3.2 1.2 0.4 0.1 0.2 - 5.1

4 1.1 0.3 0.4 0.1 0.1 0.3 2.3

5 - 0.3 0.1 0.2 0.1 - 0.7

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 7.5 7.2 3.2 1.3 19.2

Log length (feet)

<20 4.0 3.9 0.8 0.8 9.5

20-50 2.8 2.8 1.7 0.3 7.6

51-100 0.7 0.5 0.5 0.2 1.9

>100 - - 0.2 - 0.2

Log decay class

1 0.2 - 0.2 - 0.4

2 1.0 0.3 0.1 0.3 1.7

3 3.0 1.9 0.7 0.2 5.8

4 1.3 3.2 1.2 0.6 6.3

5 2.0 1.8 1.0 0.2 5.0
216 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Wildlife

These stands may offer hiding and thermal cover to large game, but forage

possibilities appear to be transitory. Most of the shrub and forb species occurring

on these sites are low value components of the large game diet. Thus, of the

substantial number of species occurring in these stands, wandering daisy and

possibly broad leaved lupine are the only real staples in the forb layer that occur

with reasonable frequency and cover. Bolander’s bluegrass and Ross’ sedge are

also staples from the grass layer that occur with enough frequency and cover to

provide reasonable amounts of forage. Evidence of deer and pocket gopher was

common on these sites

Range

These are transitional range sites that are used by livestock since they often lie

adjacent to primary range sites such as meadows and other moist habitats. In the

forb layer, California corn lily, mountain sweet cicely, and possibly broad leaved

lupine are secondary range forage species. Thurber’s bent grass is a primary

species in the grass layer. The moderate levels of occurrence and cover of the

primary and secondary species probably provide important contributions to

range use. Cattle use was often observed on these sites, and their locations near

wet areas such as meadows and streams would encourage range utilization of

available forage.

Management Recommendations

Few stands have been treated in this type. Where they have, silvicultural systems,

cutting methods, and regeneration patterns are unclear. A few were treated as

part of meadow restoration projects. In some cases lodgepole pine dominates

early natural regeneration; in other cases the high water tables presumed to exist

on these sites seems to preclude regeneration for a considerable period of time.

Early stand development is poorly understood. Successional sequences after

disturbance seem to indicate movement toward somewhat persistent forb and

grass communities that are replaced in time with lodgepole pine forests. Over

longer periods as crowns close, lodgepole pine becomes mixed with shade

tolerant red fir, but lodgepole often continues to dominate these sites.

Stands have moderate productive capacity and flexibility for stand

management. Stand structures are variable, but species composition is somewhat

limiting, and the ability of sites to respond to treatment are uncertain. The ability

to predict results of treatment are not based on wide experience or research

results at this time. Recommendations for harvesting at the present time would

be to treat stands in this association with caution. Any treatment planned in

these stands should be done with the realization that a high degree of uncertainty

must accompany expected results. Management may be more appropriately

directed at maintaining the landscape level diversity this association provides.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 217

Lodgepole Pine//Woodlands Association

Pinus contorta//woodlands

PICO//WOODLANDS

CPLCPL12

Sample size: 10

Distribution

The lodgepole pine//woodlands plant association is located at middle to upper

elevations throughout the central and southern Sierra. Latitudes and longitudes

span the range of the study area. Sample sites occurred in higher proportions on

the Inyo National Forest but from two widely separated sources. One group was

located on the Kern Plateau adjacent to the Sequoia National Forest on the

southeastern side of the study area, and the other was located near Mammoth

Mountain in the central portion of the eastside. Stands range in size from less

than an acre to as much as 50 acres or larger, but most are less than 25 acres due

to natural patchiness in the landscape.

Environment

Elevations are wide ranging, but generally stands lie above 7,500 feet. Aspects

are varied and evenly distributed across the landscape on moderate to gentle

slopes that characteristically are less than 20 percent. Stands occur in two

somewhat disparate locations. Commonly, they lie on lower slopes and benches.

These locations are characteristic of many lodgepole stands; however, a high

proportion of this association also occurs on broad, somewhat rounded, ridge

tops. Few appear to be located on middle slopes. Bare ground and surface gravel

occur in these plant communities at significantly higher levels, and litter cover

and litter depth are significantly less than on most other sites Microrelief is

typically uniform and smooth; however, on occasional sites, surfaces are broken

and hummocky due to large amounts of surface rock. Sites in this association

have characteristics of dry habitats. Stress indexes are moderate to high and
218 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

reflect dry conditions overall. Stands with abundant surface rock indicate there

may be considerable subsurface variation in water availability that affects plant

distribution in these stands. Thus, within the same stand, some soils are deep,

and moisture supply is adequate, but in others depths are shallow and moisture

supplies are low. The end result is variation of site conditions within a stand, and

a patchy distribution of vegetation.

Variable Mean Range

Elevation (feet) 8,174 7,360-9,080

Slope (pct.) 12 5-30

Solar radiation index 0.490 0.445-.536

Bare ground (pct.) 28 3-80

Surface gravel (pct.) 15 1-55

Surface rock (pct.) 10 0-53

Litter (pct.) 44 3-88

Litter depth (inches) 0.6 0.1-1.0

Stress index 0.50 0.38-0.66

Aspect: All.

Range: All.

Position: All.

Range: All.

Vegetation

Stands are open woodlands with an understory of scattered forbs and grass. This

association has the lowest average total vegetative cover and some of the lowest

tree and shrub cover of all the forested associations in the upper montane.

Overstory composition is characterized by lodgepole pine usually mixed with

scattered red fir. These species usually indicate moderate to moist sites in most

cases and, as noted, their dispersed distribution within the community may

indicate a patchy nature to the moisture supply.

The shrub component is essentially missing or occurs at very low levels, but

the forb layer is characterized by species that indicate generally dry habitats.

Thus, pussy paws, broad seeded rock cress, naked stemmed eriogonum, and

Coville’s gayophytum are all reflective of generally drier habitats. The grass

layer, too, contains moderate to dry site indicators such as bottle brush

squirreltail, Ross’ sedge, and western needlegrass. Bolander’s bluegrass is present

in some cases to indicate moderate to somewhat moist conditions at specific

locations within stands.

Conifer regeneration is somewhat low. The average number of seedlings in

over 300 per acre, but distributions are skewed, and the median is 115. Usually,

seedling counts are higher than 100 per acre; but only occasionally will sites have

more than 250. Red fir is the dominant species in the regeneration layer; lodgepole

pine is commonly present as well, but it occurs in substantially fewer numbers

than red fir. Other species are rarely encountered. Compared to other

associations, lodgepole pine is regenerating on a significantly higher proportion

of sites, and red fir is regenerating on a significantly lower proportion.

Plant species diversity is quite low. It is among the least diverse of the upper

montane plant associations. Stands have a low number of species overall, and

these are concentrated in the overstory tree layer. Sites are dominated by few tree

species, which outweigh cover values of the shrub, forb, and grass layers.

Abundant species are few in number and concentrated in the tree layer.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 219

The oldest trees in these stands are typically older than 250 years, but

average stand ages are comparable to most other late seral forested plant

communities in the upper montane. Lodgepole pine, although somewhat smaller

in diameter in general, is not substantially different in age from the red fir which

occupies these sites. The oldest tree sampled was a lodgepole pine at +443 years,

and the oldest red fir sampled was +392 years. The oldest western white pine

sampled in the association was +250 years old.

Stand replacing fires probably occur in this association, but they do not

appear to be a widespread or frequent phenomenon. Open stands with widely

separated trees, the natural patchiness of upper elevation landscapes, and the

presence of larger, somewhat fire resistant individuals, tends to preclude fire

caused stand replacement and results in uneven coverage and some level of

vegetation survival in most cases. These stands probably experience patchy

burns with little overall damage. Isolated large and small trees escape fire

damage in most cases. Other disturbance elements such as windthrow, insects,

disease, lightning, or avalanche are not common features of these stands, and

they do not generally result in stand replacement.

Disturbance creates opportunities for regeneration, but many microhabitats

are unsuitable for regeneration, and conifer establishment is a prolonged process

on many sites. Disturbance also provides opportunities for surviving individuals

to increase growth. Isolated patches of conifers probably escape many

disturbances and proceed through periods of crown closure and self thinning.

Isolated trees and small patches that escape repeated disturbance eventually

mature into larger members of the stand. In time, the stand develops an irregular

structure reflecting numerous disturbances, and containing large trees that are

the survivors of several stand altering events.

Cover (percent) Mean Range

Total vegetative 49 18-72

Tree 33 16-48

Shrub 1 0-2

Forb 12 1-30

Grass 7 0-30

Moss 2 0-18

Stand age (years) 226 120-345

Diversity index

Simpson 0.50 0.22-0.89

Hill numbers

N0 8.5 2.0-17.0

N1 3.47 1.22-7.48

N2 2.42 1.12-4.54

Characteristic Vegetation

Percent cover

Code Common name Constancy Mean Range

I. Overstory trees

PICO Lodgepole pine 100 26 4-48

ABMA Red fir 50 15 1-38

PICO Lodgepole pine 70 1 1-3

ABMA Red fir 70 1 1-2
220 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

III. Shrubs

RICE Squaw currant 20 1 1-1

IV. Forbs

CAUM2 Pussy paws 50 2 1-5

PESE3 Pine woods lousewort 50 1 1-1

ARPL Broad seeded rockcress 40 1 1-1

ERNUD Naked stemmed eriogonum 30 3 1-5

BRLU2 Yellow brodiaea 20 2 1-2

ERSP2 Spurry eriogonum 20 1 (1-2

GAER Coville’s gayophytum 20 10 1-20)

LUADU Drew’s silky lupine 20 1 1-1

STTO Mountain streptanthus 20 1 1-1

V. Grasses and grass-like

CARO1 Ross’ sedge 50 1 1-2

SIHY Bottle brush Squirreltail 50 5 1-20

STOC1 Western needlegrass 40 3 1-8

POBO1 Bolander’s bluegrass 30 1 1-1

STEL1 Elmer’s needlegrass 20 10 1-20

Soils

Soils are typically Entisols with occasional Inceptisols; however, stands in this

association differ from most others in containing significantly higher proportions

of Entisols. Most of these are Psamments although occasional Orthents are also

encountered. Particle size classes are usually sandy, but loamy, ashy, and

contrasting size classes are also present in some cases. Parent materials are

typically granitic; however, soils formed from tephra and ash deposits are also

present, reflecting locations near the Mammoth Mountain region. Soils are

predominantly weathered in place from bedrock, and only rarely are they formed

from deposited materials such as alluvium.

Soil depths are moderately deep to deep. Often they exceed 35 inches, but

rarely are they less than 25 inches. Topsoils are shallow; average topsoil depths

are some of the lowest in the upper montane plant communities. Usually they are

less than 7 inches. Textures in both topsoils and subsoils are usually sands, but

sandy loams also often occur in topsoils. Soils in this association differ

significantly from those on most other sites in containing a proportionately

higher number of sandy textures throughout the profile. Average subsoil coarse

fragments are the lowest of all sites in the upper montane forested communities.

Usually stands contain less than 15 percent coarse fragments in the subsoil.

The AWC of these soils is among the lowest in the upper montane, and it

reflects the influence of the coarse textured soils commonly encountered. Bedrock

formations underlying soil profiles were usually massive and unrootable thus

limiting additional sources of moisture to the site. As would be expected from

the sandy soil textures, soil drainage is typically excessive. Erodibility is low to

moderate also as a result of the coarse soil textures and moderate slopes. These

soils are also interesting from the standpoint they are among a small group that

Characteristic Vegetation (continued)

Percent cover

Code Common name Constancy Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 221

consistently contain strongly acid topsoils. Summertime soil temperatures are

wide ranging, but they are usually high, and compared to most other sites, they

have substantially higher occurrences of temperatures that exceed 53° Fahrenheit.

Variable Mean Range

Depth of soil sample (inches) 33 13-40+

Topsoil

Depth (inches) 7 2-15

Coarse frag. (pct.) 15 2-45

pH 5.3 4.6-6.0

Subsoil

Coarse frag. (pct.) 18 2-40

pH 5.8 5.0-7.0

AWC (inches) 2.7 0.5-4.6

Temp (20 inches) (Fahrenheit) 54 42-65

Productivity

Pacific Southwest Region (Region 5) site indexes are substantially lower than

dense, well-stocked forested stands in the upper montane. No site index was

higher than 3, and typically stands had site indexes of 4 or 5. Stand densities are

also low. Stand density indexes are generally less than 300, and occasionally they

are less than 200. These values are considerably lower than adjacent dense

forested stands, and stocking levels in this association attain only about 40

percent of the values reached in a fully stocked stand in the red fir-white fir

association, which is one of the densest in the upper montane. Average tree

heights are also substantially lower, reflecting the overall lower site quality and

the presence of lodgepole pine, a shorter tree in the Sierra Nevada. The tallest

tree measured was a red fir at 140 feet, but the tallest lodgepole pine was only 105

feet. Quadratic mean diameters are also small compared to those in other late

seral forested stands, and it reflects the presence of smaller lodgepole pine on

these sites. The combination of low site indexes, low stand densities, and shorter

trees results in cubic and board foot yields that on average are among the lowest

in these forests. Average values are only 25 percent of those in well-stocked plant

associations.

Stands generally have the appearance of an uneven-aged distribution of

trees, and considered collectively stands do approach this distribution, but stands

also tend to be very open (fig. 37). They commonly carry less than 100 trees per

acre, and the basal area stocking is concentrated in scattered large diameter trees.

When compared to uneven-aged stand structures with a balanced diameter

distribution and similar stocking levels, they have an excess of trees in size

classes below 18 inches, and nearly appropriate numbers of trees in size classes

larger than 24 inches. Trees larger than 40 inches in diameter are few. Compared

to an even-age distribution, stands have an excess of trees in size classes below

about 24 inches. Lodgepole pine carries the largest portion of trees in size classes

between 10 and 30 inches in most stands, and when viewed as a separate

component of the stand, distributions for this species appear even-aged. Red fir

constitutes most of the stocking in size classes below 10 inches and larger than 35

inches, but it is poorly represented in intermediate size classes.
222 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIM03 TSME

Percent 28 - 67 l 4 -

Species JUOC PILA LIDE3 PIAL POTR OUKE

Percent

Coarse Woody Debris

Snag numbers are low. When compared to many other sites in the upper

montane, snags smaller than 11 inches diameter are particularly sparse.

Otherwise, mortality appears more or less uniformly distributed in the remaining

size classes. Snags taller than 50 feet are well represented reflecting a tendency

for lodgepole pine to topple rather than break apart with time. These snags

commonly lie in decay classes l to 3. Logs are characteristically less than 30

inches in large end diameter, reflecting the presence of lodgepole pine. They are

typically less than 50 feet in length, and evidence higher levels of decay. Most

logs in these stands lie in decay classes between 3 and 5.

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

20

40

60

80

70

50

30

10

Figure 37—Number of trees by

diameter class in the lodgepole pine//

woodlands plant association.

Variable Mean Range

Region 5 site index 4 3-5

Forest survey site class 5 4-6

Stand density index 212 53-390

Quadratic mean diameter 18.7 7.8-34.1

Softwood volume (mcf/ac) 3.8 1.4-9.0

Softwood volume (mbf/ac) 20.1 1.7-64.6

Softwood basal area (sq ft/ac) 139 32-248

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 223

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0.8 1.6 1.4 0.8 0.3 4.9

Snag height (feet)

<20 - 0.4 0.8 0.3 - - 1.5

20-50 - 0.4 0.8 - - - 1.2

>50 - - - 1.1 0.8 0.3 2.2

Snag decay class

1 - - - 0.3 - 0.3 0.6

2 - 0.4 0.4 0.7 0.6 - 2.1

3 - - - 0.4 0.2 - 0.6

4 - 0.4 1.2 - - - 1.6

5 - - - - - --

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 2.4 5.2 0.8 0.8 9.2

Log length (feet)

<20 1.6 2.4 - - 4.0

20-50 0.4 0.8 0.4 0.8 2.4

51-100 0.4 1.6 0.4 - 2.4

>100 - 0.4 - - 0.4

Log decay class

1 --- - -

2 0.8 0.8 0.2 - 1.8

3 0.8 2.4 0.3 - 3.5

4 0.4 0.4 - 0.4 1.2

5 0.4 1.6 0.3 0.4 2.7

Wildlife

Wildlife forage values appear to be moderate. Of the species occurring on these

sites naked stemmed eriogonum, spurry eriogonum, and Drew’s silky lupine in

the forb layer are all staples. Ross’ sedge, bottle brush squirreltail, western

needlegrass, and Bolander’s bluegrass are also staples in the grass layer. Except

for Ross’ sedge, bottle brush squirreltail, and western needlegrass, however, the

other forb and grass species occur as scattered members of this association. Deer

sign was generally observed on these sites, but pocket gophers tended to be

infrequent.

Range

Range potential in this association appears to be transitory as livestock move

between primary range sites such as meadows and other moist habitats. Cattle

use was usually observed in these stands. Drew’s silky lupine is perhaps a

secondary forage species in the forb layer, but frequency and cover are low. Bottle
224 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

brush squirreltail and western needlegrass are secondary livestock forage species

that occur with reasonable frequency and cover in this association. Other shrub,

forb, and grass species occurring on these sites are of low value for livestock, and

it would appear forage potential is generally low in these late seral stands.

Management Recommendations

Relatively few stands in this association have been harvested. Silvicultural

systems, cutting methods, regeneration strategies, and stocking levels used in

the management of any forested stand are relatively untried. Where stands have

been harvested and disturbance has occurred, regeneration patterns were

unclear. No sites were observed where stands were harvested, prepared for

planting, and planted with any systematic silvicultural approach. Occasional

sites have large quantities of boulders and surface rock that severely limit

treatment options, and many of these sites should not be considered suitable for

timber production.

Species composition, stand structure, and yields in these late seral stands is

felt to reflect site capability. The open nature of these stands indicates that

regeneration is a lengthy and variable process under most circumstances. Limited

opportunities exist for salvage as it occurs, but on these open sites it would

appear the sparse woody debris that accumulates would better serve as part of

the nutrient pool and as wildlife habitat. Recommendations for treatment at the

present time would be to enter stands in this type with caution and expect that

results can be uncertain. Management emphasis should provide for existing

wildlife habitat, plant species richness, and the landscape level diversity such

stands provide.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 225

Lodgepole Pine Association

Pinus contorta

PICO

CPLCPL13

Sample size: 8

Distribution

The lodgepole pine plant association is widespread at higher elevations in the

Sierra Nevada. These are the stands that are found at the highest elevations of the

upper montane. They often share this position with the red fir-western white

pine-lodgepole pine and lodgepole pine/sagebrush associations, and in

combination they straddle the crest at higher elevations. The association was

sampled only on the Inyo and Toiyabe National Forests, but it has been observed

throughout the range as the upper montane transitions into the subalpine above.

Stands can cover extensive areas, but most are less than 100 acres because of

natural patchiness in the landscape.

Environment

Elevations lie predominantly above 8,500 feet, and average elevations are the

highest of any association in the upper montane. The lowest stand sampled, for

example, was at 8,300 feet on the Toiyabe National Forest. Aspects are varied.

Northeast and northwest facing slopes are typical, and solar radiation levels are

commonly low due to the northerly aspects; however, south facing aspects are not

uncommon. Slopes are substantially less than most other associations in the upper

montane, and stands commonly occupy slopes less than 20 percent. Stands are

typically found at the bottom of slopes or on benches where they join open alpine or

subalpine vegetation above. This association has considerably higher levels of surface

gravel compared to other sites, although litter cover is generally high as well. Stress

indexes tend to be lower, reflecting the effects of higher elevation settings.
226 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Variable Mean Range

Elevation (feet) 8,877 8,300-9,320

Slope (pct.) 16 4-30

Solar radiation index 0.471 0.381-0.527

Bare ground (pat.) 3 0-5

Surface gravel (pct.) 11 2-36

Surface rock (pct.) 2 0-5

Litter (pct.) 85 64-99

Litter depth (inches) 1.0 0.6-1.4

Stress index 0.45 0.38-0.57

Aspect: All.

Range: All.

Position: Lower slopes.

Range: Ridgetops, upper, middle, and lower slopes, benches.

Vegetation

Stands are moderately dense forests with open understories. Tree cover is

moderate, but it is substantially less than many of the forested associations that

lie at lower elevations. On most sites lodgepole pine is the only member of the

overstory. This association marks the transition into the subalpine forests at

higher elevations in the Sierra Nevada, and red fir occurs as widely scattered

remnants in otherwise lodgepole pine dominated forests. Western white pine is

rarely a member of the stand. These communities are often interspersed with the

red fir-western white pine-lodgepole pine, lodgepole pine/sagebrush, and

lodgepole pine//woodland associations in higher elevation settings. They are

mesic sites as indicated by the presence of both lodgepole pine and red fir.

A shrub layer is essentially absent, although Sierra gooseberry occurs to

indicate mesic conditions in rare cases. Forb cover is among the lowest in the

upper montane forested plant associations, but the species present indicate a mix

of moderate to dry conditions. Thus, broad seeded rock cress usually indicates

drier sites, and white veined wintergreen indicates more moderate conditions

and Fendler’s meadow rue indicates moist sites. Grass cover is moderate, and the

mix of species present also indicate moderate to dry sites. Ross’ sedge indicates

the mesic conditions occurring in most stands, but western stipa, generally a dry

site indicator, is frequently present as well.

Conifer regeneration is moderate to low. The average number of seedlings is

over 500 per acre, and sites usually had more than 250 per acre. Whitebark pine,

red fir, and western white pine are present on occasion, but the regeneration

layer is dominated by lodgepole pine; it carries substantially higher numbers of

regeneration than any other species. Lodgepole pine is regenerating significantly

more often on these sites compared to others in the upper montane. Red fir is

regenerating at significantly lower levels when compared to other plant

associations.

Plant species diversity is extremely low. It has few species overall, and most

sites are dominated by a single tree species. The shrub layer is essentially absent,

and the tree cover far outweighs cover values of the shrub, forb, and grass layers.

Abundant species are relegated to little more than a single species in most

stands.

The oldest trees in these stands are generally older than 250 years. This

includes the lodgepole pine which is smaller in diameter than most associated

species but not significantly different in age. Average stand age of these stands is
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 227

also not substantially different from most others in these forests. Most stands

have a uniform size distribution since lodgepole pine rarely attains large

diameters, and many trees cluster in size classes between 18 and 30 inches.

However, age differences among the individuals in a stand are often

considerable, and ages of dominant trees commonly differ by more than 100

years in a +300 year old stand. The oldest tree sampled in this association was a

lodgepole pine at +377 years.

Stand replacing events undoubtedly occur in this association, but they do

not appear to be frequent or cover large areas. Fire would be the most likely

cause of large scale mortality, and lodgepole pine is highly susceptible to fire

damage. However, the setting of many stands on lower slopes with gentle

topography, cooler north aspects, at high elevations, the isolation of many stands

on the landscape, and the structure of the stands with open understories, tend to

mitigate against large fires. These stands probably experience infrequent, patchy

burns with some portion of the stand being completely consumed, while others

are left with little damage. Avalanche can replace stands located on lower and

middle slope positions. Most of these appear to be infrequent and occur at

scattered locations across the landscape. Understories, including smaller trees,

generally remain intact. Other disturbance elements such as windthrow, insects,

disease, and lightning do not appear to cause stand replacement over large areas.

It is likely that disturbance occurs continuously at various scales in these stands,

and this results in the creation of various size gaps that constantly change

structure.

Reproductive strategies such as reasonably constant seed production are

present in the tree species on these sites. Lodgepole pine in the Sierra Nevada

appears to be a prolific seeder, and in most cases the species composition of

future stands is largely determined by the occurrence of this species in the

overstory. Stand development is not fully understood in this association. It

appears to, be sporadic as opportunities for regeneration and growth arise in

response to disturbance. Many stands have an even-aged structure with the

implication of a common regeneration event; however, as noted, several widely

separated age classes are often present, and when several stands are viewed

collectively, an irregular structure is apparent that suggests gap processes are

important. Stands apparently do not go through a prolonged early successional

period in a grass/forb or shrub phase, but in most cases conifer establishment is

a process that can occupy a considerable period of time. It is likely that

regeneration becomes established in gaps, grows, self-thins, and develops to

maturity similar to other associations in the upper montane, but the narrower

distribution of diameters in lodgepole pine gives the appearance of uniform ages

in late seral stands. In time, several size and tree classes are represented, and the

stand exhibits an irregular structure. As stands occupy sites for longer periods,

successive disturbances continue to develop and maintain stand structures until

an infrequent stand replacing event occurs and a new stand emerges.

Cover (percent) Mean Range

Total vegetative 67 42-90

Tree cover 59 39-73

Shrub 0.4 0-1

Forb 3 1-9

Grass 10 0-61

Moss 0.1 0-1

Stand age (years) 250 186-328
228 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Diversity index

Simpson 0.71 0.38-0.94

Hill numbers

N0 8.1 3.0-11.0

N1 1.97 1.15-3.24

N2 1.50 1.06-2.60

Characteristic Vegetation

Percent cover

Code Common name Constancy Mean Range

I. Overstory trees

PICO Lodgepole pine 100 57 31-73

ABMA Red fir 25 6 4-8

II. Understory trees

PICO Lodgepole pine 100 3 1-16

PIAL Whitebark pine 62 1 1-2

ABMA Red fir 37 1 1-1

PIMO3 Western white pine 37 1 1-1

III. Shrubs

RIMO Sierra gooseberry 25 1 1-1

IV. Forbs

ARPL Broad seeded rock cress 75 1 1-1

PYPI White veined wintergreen 50 1 1-1

PESE3 Pine woods lousewort 25 3 1-5

THFE Fendler’s meadow rue 25 1 1-1

V. Grasses and grass-like

CARO1 Ross’ sedge 75 1 1-1

STOC1 Western needlegrass 62 1 1-60

CAR-1 Sedge 25 1 1-1

PONE1 Hooker’s bluegrass 25 1 1-2

SIHY Bottle brush squirreltail 25 1 1-1

STCO1 Columbia needlegrass 25 1 1-1

STEL1 Elmer’s needlegrass 25 1 1-1

Soils

Soil are Entisols, Inceptisols, and Mollisols. The Entisols and Inceptisols occur in

equal abundance, but this association contains significantly higher proportions

of Entisols and Mollisols than most other sites. Within these taxonomic

groupings, Umbrepts, Orthents, and Borolls are encountered most frequently.

Particle size classes show similar variation indicating soil profiles with significant

differences in rock fragment content compared to most other sites. Some are

skeletal but loamy, medial, ashy, cindery and contrasting size classes also occur,

and collectively they are more common than the skeletal size classes. Parent

Cover (percent) Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 229

materials also come from a variety of sources. They are commonly volcanic and

derived from tephra deposits and andesitic and rhyolitic flow rocks reflecting

the location of sample sites in the north and on the eastside. Granitic and mixed

parent materials also occur, and throughout much of the range such bedrock

material probably occupies more of the landscape where this association occurs.

Regardless of parent materials, however, most of these soils are formed from

alluvial deposits reflecting locations on lower slope positions.

Soils in this association are deep. Samples were commonly deeper than 40

inches, and seldom were they less than 35. Textures in the topsoils were usually

sandy loams with some gravelly sands and a few loams and clay loams. Subsoil

textures were similar except they contain fewer sandy loams and more sandy

clay loams and clays. Subsoils differed significantly from those in other plant

associations in containing higher proportions of finer textures such as clay

loams, and clays. Topsoil coarse fragment content is variable, but it tends to be

high. Coarse fragments in these horizons are among the highest in the upper

montane on average, and some sites contain more than 65 percent coarse

fragments in the topsoil.

The AWC in these sites is moderately high, but it is not substantially different

from most other forested sites in the range. Although soils are deep in general,

the effect of sites with coarse soil textures and high coarse fragments moderates

the water holding capacity in general. Parent materials were commonly fractured

and rootable thereby increasing the available moisture supply to these stands.

Sites are typically well drained, but they can be excessively drained on occasion.

Erodibility is low to moderate due to coarse soil textures and moderate slopes.

Even though these stands occur at higher elevations, soil temperatures are

moderately warm. Typical stands have soil temperatures that exceed 49°

Fahrenheit, reflecting the more open stand conditions and occasional south

aspects of some sites.

Variable Mean Range

Depth of soil sample (inches) 39 31-40+

Topsoil

Depth (inches) 11 4-23

Coarse fragments (pct.) 33 8-95

pH 5.8 4.5-6.5

Subsoil

Coarse fragments (pct.) 38 8-85

pH 5.9 5.2-6.9

AWC (inches) 3.4 1.2-5.8

Temp (20 inches) (Fahrenheit) 51 46-60

Productivity

Site indexes are low. Pacific Southwest Region (Region 5) site indexes for all

stands sampled were 4 or 5. Stand densities, on the other hand, were moderately

high. Based on average stand density indexes these sites carry nearly 85 percent

of the stocking that can be carried by the red fir-white fir plant association, which

is one of the densest in the upper montane; stand density indexes commonly

exceed 400 in these stands. Tree heights, however, are substantially shorter than

those in other dense forested plant associations. This reflects the presence of

large numbers of lodgepole pine, which is generally a shorter tree in the Sierra

Nevada. The tallest tree in the association was a lodgepole pine which measured

95 feet. Quadratic mean diameters are among the lowest in upper montane
230 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

forests, reflecting the abundance of lodgepole pine in these stands. The

combination of low site indexes and proportionately shorter trees overrides the

effect of higher stand densities, resulting in cubic and board foot yields that are

about 30 percent of those in the red fir or red fir-white fir associations.

When some stands are viewed in the field they often have the appearance of

an even-aged or two-storied structure with very scattered predominant red fir

over an even-aged stand of lodgepole pine; however, others exhibit different

structures, and taken collectively the distribution approximates that of an

uneven-aged stand (fig. 38). When compared to uneven-aged structures in stands

with similar stocking and balanced diameter distributions, these stands generally

carry too many trees in size classes below 40 inches. The number of trees in size

classes between 18 and 30 inches approximates an even-aged distribution.

Viewed as a separate component of the stand, distributions in these size classes

impart a characteristic even-aged appearance to many stands. When compared

to an even-aged distribution, however, stands carry too many trees in size classes

below 18 inches and more trees in size classes larger than 30 inches than would

be appropriate.

Variable Mean Range

Region 5 site index 4 4-5

Forest survey site class 5 5-6

Stand density index 448 341-606

Quadratic mean diameter 14.4 8.7-21.8

Softwood volume (mcf/ac) 4.6 2.8-5.7

Softwood volume (mbf/ac) 22.8 9.9-28.3

Softwood basal area (sq ft/ac) 275 208-360

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

40

80

120

160

140

100

60

20

Figure 38—Number of trees by

diameter class in the lodgepole pine

plant association.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIM03 TSME

Percent 1 - 93 - - -

Species JUOC PILA LIDE3 PIAL POTR OUKE

Percent - - - 6 - -
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 231

Coarse Woody Debris

Snag numbers are moderate. They are comparable to those found in other dense

stands such as the red fir association. Snags are concentrated in size classes less

than 25 inches, which reflects continued thinning of suppressed individuals and

the presence of lodgepole pine. Snags are distributed among all height classes;

however, they are typically less than 50 feet tall. Snags taller than 50 feet are

indicative of the tendency of lodgepole pine snags to topple rather than break

apart from the top with the passage of time. Snags are distributed among all

decay classes, but commonly they occur in classes 1 to 3. Most logs are smaller

than 30 inches in large end diameter. Log lengths are commonly less than 50 feet,

but a high proportion also occur between 50 and 100 feet indicating the presence

of lodgepole pine that have fallen as complete trees. Decay classes between 3 and

5 predominate in these logs.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 4.0 2.8 4.1 0.4 0.4 0 11.7

Snag height (feet)

<20 2.5 - 4.1 - - - 6.6

20-50 1.5 1.1 - 0.1 - - 2.7

>50 - 1.7 - 0.3 0.4 - 2.4

Snag decay class

1 0.6 - - 0.1 0.4 - 1.1

2 0.9 1.2 - 0.1 - - 2.2

3 1.9 1.6 1.6 0.1 - - 5.2

4 0.3 - 2.5 0.1 - - 2.9

5 0.3 - - - - - 0.3

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 7.3 8.7 2.7 1.3 20.0

Log length (feet)

<20 5.3 2.0 - 0.6 7.9

20-50 2.0 4.0 - 0.7 6.7

51-100 - 2.7 2.7 - 5.4

>100 -----

Log decay class

1 - 0.7 - - 0.7

3 2.0 4.0 1.4 - 7.4

4 3.3 0.7 1.3 0.6 5.9

5 2.0 3.3 - 0.7 6.0

Wildlife

These stands may offer hiding and thermal cover to large game, but presence is

probably transitory in nature as animals move to areas with more abundant

forage. Forage is concentrated in the grass layer. Hooker’s bluegrass is a preferred
232 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

large game species that occurs in low cover on a few sites, but Ross’ sedge, other

sedge species, bottle brush squirreltail, western needlegrass, and Columbia

needlegrass are staples that also occur with low cover on these sites. Collectively

these species may constitute a substantial amount of available forage. Other

forage species occurring in these stands are of such low frequency or cover value

that they are not important components of the large game diet. Evidence of deer

and pocket gopher presence was commonly observed on these sites.

Range

Stands are transitional range sites that are used by livestock to access primary

range sites, such as meadows and other moist habitats. Cattle use was generally

observed in these stands. Hooker’s bluegrass is a primary range species, and

western needlegrass is a secondary species that occurs with relatively high

frequency. Columbia needlegrass, and bottle brush squirreltail are secondary

species that collectively occur with reasonable frequency and probably also

contribute to range forage values.

Management Recommendations

Few stands in this association have been harvested. These have occurred

primarily on the eastside where an even-aged silvicultural system was applied

consistent with lodgepole pine management elsewhere in the West.

Establishment of planted Jeffrey pine and lodgepole pine, however, has generally

been poor. In some cases, 15 years elapsed before natural seedlings began to

establish, but after more than 25 years several of these sites appear to have at

least moderate stocking. The species regenerating in most cases is lodgepole pine

and red fir. Successional patterns are not well understood, but high levels of

shrub competition do not seem to be a factor in past regeneration efforts.

Stands have low productive capacity, and they should not be considered for

traditional forest management in most cases. If harvested, options for silvicultural

systems and cutting methods can vary to take advantage of differences in stand

structure and density. Natural regeneration can be a viable option, but long time

periods may be involved in obtaining success. Stand openings should be kept

small and seed sources near to encourage natural regeneration. These stands do

not regenerate abundantly soon after disturbance as do most other lodgepole

pine stands in the Sierra. On north facing aspects small clearcuts can be utilized,

but on south aspects shelterwood cutting or a silvicultural system that maintains

constant seed source is recommended.

Harvesting at the present time should be conducted with caution and the

knowledge that results are uncertain. Limited opportunities exist for salvage

when it occurs, but on these sites it would appear that woody debris left in the

form of snags and logs for wildlife or part of the nutrient pool would be better

direction. Management emphasis should provide for existing wildlife habitat,

plant species richness, and the landscape diversity this association provides to

upper montane forests.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 233

Red Fir-Lodgepole Pine/White Flowered Hawkweed Association

Abies magnifica-pinus contorta/hieracium albiflorum

ABMA-PICO/HIAL

CFRCPL11

Sample size: 48

Distribution

The red fir-lodgepole pine/white flowered hawkweed plant association occurs

throughout the central and southern Sierra Nevada. Although it was sampled

primarily in the central portion of the study area, it occurred in every National

Forest and Park in the range except for the Lake Tahoe Basin Management Unit.

It is a common associate of the lodgepole pine/Gray’s lovage association. Stands

often cover extensive areas in gentle terrain along drainage bottoms.

Environment

In general, lodgepole pine exhibits a wide elevational range in the Sierra Nevada.

This association reflects that distribution, and it can be found at all elevations of

the upper montane. The lowest elevation occurred on the Eldorado National

Forest, and the highest was on the Inyo. Stands reflect the increase in elevation

with decreasing latitude that is characteristic of these forests, and those that

occur in the south will generally occupy higher elevations than those in the

north. Aspects are varied, but frequently northeast and northwest facing slopes

are encountered, resulting in solar radiation levels that are significantly lower

than most other sites. Slopes are shallow. Characteristically, they are less than 20

percent, and often they are less than 10 percent. Stands typically lie on benches,

lower slopes, and in bottom positions adjacent to and somewhat upslope from

flat areas such as meadow complexes or drainage bottoms. Stands in this

association have considerably less bare ground and surface gravel compared to

most others, and microrelief is usually smooth and uniform to gently undulating.

Stress indexes are among some of the lowest in the upper montane and reflect the

generally moderate conditions encountered on these sites.
234 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Variable Mean Range

Elevation (feet) 7,831 6,540-9,520

Slope (pct.) 13 2-40

Solar radiation index 0.479 0.359-0.561

Bare ground (pct.) 2 0-40

Surface gravel (pct.) 4 0-37

Surface rock (pct.) 3 0-33

Litter (pct.) 90 45-99

Litter depth (inches) 1.6 0.1-7.0

Stress index 0.44 0.29-0.61

Aspect: NE,NW,SW.

Range: All.

Position: Lower slopes, benches.

Range: All.

Vegetation

Stands are dense multi-layered forests with understories composed of patches of

dense conifer regeneration. Average tree cover is one of the highest in the upper

montane. The overstory is dominated by red fir in mix with lodgepole pine.

Rarely does lodgepole pine equal or exceed the stocking levels of red fir, but

together these two species occupy most of the growing space in late seral stands.

White fir is an occasional member of some stands indicating lower elevation

sites. All of the overstory tree species present are adapted to moderate and moist

sites. This association often lies adjacent to, and upslope from, lodgepole pine/

Gray’s lovage sites. Conditions in these two associations are similar, except the

red fir-lodgepole pine/white flowered hawkweed plant association generally

occupies drier habitats. Often the two occur adjacent to each other as conditions

change from moist to drier sites.

Understories are sparse. Shrub cover is among the lowest in upper montane

forests, and shrubs often occur as isolated patches and individuals scattered in

the understory. Sierra gooseberry and alpine prickly currant are moist site

indicators that are present in a few cases. The forb layer, on the other hand,

usually has an assemblage of moderate site indicators. White flowered hawkweed

and mountain violet, for example, are mesic site indicators. Mountain sweet

cicely, Kellogg’s bedstraw, and Bolander’s bluegrass are indicators of moderate

to moist habitats. Although white flowered hawkweed does not carry the high

frequency usually attributed to indicator species for which an association is

named, it is a constant but widely scattered member of most stands. It becomes

absent with increase in elevation or in most eastside stands, but it is used in the

name to aid in distinguishing the central concept of this association from others

with mixed red fir and lodgepole pine.

Conifer regeneration is high in these stands. Late seral stands average over

1,200 seedlings per acre, and they often carry more than 500 per acre. White fir

and lodgepole pine are usually present in the regeneration layer, but natural

regeneration is dominated by red fir, and the number of natural lodgepole pine

seedlings is far fewer than red fir in most instances. The high numbers of red fir

seedlings often impart a characteristic appearance to many stands in which an

overstory of mixed red fir and lodgepole pine occur over a dense understory of

red fir seedlings and saplings. Red fir, white fir, and lodgepole pine are all

regenerating more frequently than in other associations.

Plant species diversity is moderately high for upper montane forests.

Compared to other plant associations the total number of species is moderate.

This results from the lack of forb and grass species that are able to frequent the
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 235

dense forested cover. Shrub species are also sparse. Sites are dominated by a few

tree species that outweigh the cover values in the forb and grass layers. Abundant

species are few in number, and they are concentrated in the tree layer.

The oldest trees in these stands are commonly greater than 200 years. These

stands are essentially the same average age as other forested associations in the

upper montane, and lodgepole pine, although smaller in diameter, is not

substantially different in age from the larger red and white fir. The oldest tree

sampled in this type was a red fir at +470 years. The oldest lodgepole pine

encountered was estimated at +364 years, and the oldest white fir was estimated

at +375 years.

Stand replacing events probably occur in this association, but they do not

appear to be frequent or large scale phenomenon. The setting of many stands on

cooler north aspects or along drainage bottoms with gentle topography, and the

structure of the stands with open understories and the presence of large

individuals tend to preclude fire caused stand replacement. Other disturbance

elements such as windthrow, insects, disease, lightning, or avalanche also do not

appear to affect large areas in these stands. It is likely that disturbance from

several elements occur continuously on various scales, and this results in the

creation of various sized gaps with constantly changing structures through time.

Reproductive strategies such as reasonably constant seed production is

present in most of the tree species in these stands. Lodgepole pine, at the

elevations commonly encountered in this association, is a prolific seeder with

rapid early height growth. Red fir is a shade tolerant species that can assume

dominance in these stands as they develop; however, lodgepole pine, which is

shade intolerant, is undoubtedly maintained by disturbances that open stands

and provide seed beds. In most cases the species composition of future stands is

largely determined by species presently on the site.

After disturbance these stands do not go through a prolonged period in a

grass/forb or shrub phase. Often lodgepole pine occupies sites in abundance

soon after disturbance. Once regeneration is established it grows, self thins, and

matures, and other portions of the stand continue to be affected by disturbance.

As patches close and tree cover increases, shade tolerant species such as red and

white fir become established. These species continue to seed in and grow in

height until they overtop the lodgepole pine. In time, and without further

disturbance, they can dominate the overstory. Generally, however, disturbance

will occur before the stand is completely dominated by fir, and this allows an

increase in the lodgepole component once again. In time, several size classes,

including a substantial portion of larger trees and mixed species, are represented,

and the stand exhibits an irregular structure with many small relatively evenaged patches. As stands occupy sites for longer periods, multiple disturbances

continue to be important in maintaining structures and species composition until

an infrequent stand replacing disturbance occurs, and a new stand emerges.

Cover (percent) Mean Range

Total vegetative 80 47-99

Tree 73 43-95

Shrub 2 0-40

Forb 8 0-95

Grass 2 0-25

Moss 1 0-10)

Stand age (years) 198 102-318

Diversity index

Simpson 0.48 0.17-0.76
236 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Hill numbers

N0 10.4 5.0-24.0

N1 3.31 1.78-7.36

N2 2.37 1.32-5.77

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

PICO Lodgepole pine 100 20 5-83

ABMA Red fir 98 49 6-99

ABCO White fir 27 23 5-53

II. Understory trees

ABMA Red fir 96 6 1-46

PICO Lodgepole pine 67 1 1-2

ABCO White fir 38 2 1-23

III. Shrubs

None

IV. Forbs

PESE3 Pine woods lousewort 65 1 1-4

HIAL White flowered hawkweed46 3 1-20

VIPU Mountain violet 35 1 1-2

COTOW Wright’s blue eyed mary 27 1 1-2

ARPL Broad seeded rock cress 23 1 1-1

KEGA Kellogg’s bedstraw 23 1 1-4

OSCH Mountain sweet cicely 21 3 1-20

COMA4 Spotted coral root 21 1 1-1

V. Grasses and grass-like

POBO1 Bolander’s bluegrass 44 1 1-2

CARO1 Ross’ sedge 33 2 1-8

CAR-1 Sedge 31 2 1-10

Soils

Common soils in this association are Inceptisols, and they occur in the Xerumbrept

and Xerochrept great groups with almost equal frequency. Occasional Entisols,

and rare Alfisols, and Mollisols are also encountered. Particle size classes are

distributed between skeletal and loamy and indicate relatively moderate levels of

rock fragments in the profile. These soils are usually derived from granitic parent

materials although occasional soils are derived from volcanic substrates such as

the flow rocks and lahars of the Mehrten formation, and the tephra deposits of the

eastside. A few sites developed from metamorphic parent materials. Soils are

usually formed in place from bedrock, but occasionally they are formed from

glacial till or alluvial deposits.

Soils are deep. Typically, they exceed 40 inches, and rarely are they less than

25 inches. These are medium to moderately coarse textured soils. Textures in

Cover (percent) Mean Range
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 237

both the topsoil and subsoil exhibit similar distributions. They are usually sandy

loams, although occasional loams and a few sands can be encountered.

The average AWC of these soils is among the highest in the upper montane.

It reflects the deep soils present in most stands. Bedrock conditions below lithic

contacts are commonly fractured and rootable thereby increasing the available

water supply to these sites. Soils are typically well drained, and erodibility

ranges from moderate to high, reflecting differences in soil texture on individual

sites. Soil temperatures are somewhat wide ranging, but overall averages are

cooler than most other associations in the upper montane, and they often lie

below 49° Fahrenheit.

Variable Mean Range

Depth of soil sample (inches) 37 24-40+

Topsoil

Depth (inches) 9 2-28

Coarse fragments (pct.) 20 1-95

pH 5.6 4.5-6.8

Subsoil

Coarse fragments (pct.) 30 4-87

pH 5.7 4.7-6.5

AWC (inches) 3.7 1.0-6.0

Temp (20 inches) (Fahrenheit) 47 36-64

Productivity

Site indexes are wide ranging. Typically, however, Pacific Southwest Region

(Region 5) site indexes are 2 or better, and only rarely are they less than 3. Average

stand densities are among the highest of the upper montane forested associations.

Stocking levels based on average stand density indexes are as high as fully stocked

stands in the red fir or red fir-white fir associations, and they usually exceed 500 in

late seral stands. Average tree heights are somewhat lower due to the presence of

lodgepole pine, which is generally a shorter tree in the Sierra Nevada. This is

counterbalanced to large degree, however, by red fir heights that are quite tall due

to higher site indexes. The tallest tree in the association was a red fir which

measured 182 feet compared to the tallest white fir of 177 feet and the tallest

lodpepole pine of 130 feet. Quadratic mean diameters for stands in this association

are also lower compared to those in other late seral forested stands, and this

reflects the presence of smaller lodgepole pine in the stands. The combination of

higher site indexes, high proportions of the stocking in red fir, and high densities

result in stands that are among the most productive in the upper montane.

Many individual stands have the appearance of a two storied structure;

however, they commonly exhibit other structures, and taken collectively they

can be considered irregular (fig. 39). The distribution of stems overall actually

approximates those of an uneven-aged structure to some degree. Compared to

uneven-aged structures in stands with similar stocking and balanced diameter

distributions, however, they usually contain too many trees in smaller size

classes, and too many trees in size classes larger than 35 inches. Compared to an

even-aged distribution, there are far too many trees in size classes below 24

inches and more trees in size classes larger than 30 inches than would be

appropriate. Red fir carries the largest portion of trees in size classes smaller than

24 inches, conveying their characteristic uneven-age structure. Lodgepole pine

between seedling size and 10 inches are largely absent.
238 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Variable Mean Range

Region 5 site index 2 0-5

Forest survey site class 3 1-6

Stand density index 531 272-953

Quadratic mean diameter 18.3 7.4-35.5

Softwood volume (mcf/ac) 11.6 4.4-23.4

Softwood volume (mbf/ac) 73.6 22.0-165.6

Softwood basal area (sq ft/ac) 354 187-560

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

40

80

120

160

140

100

60

20

Figure 39—Number of trees by

diameter class in the red fir-lodgepole

pine/white flowered hawkweed plant

association.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 63 8 28 1 - -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag numbers are quite high. In particular, the number of snags less than 11

inches in diameter is large. Snags are distributed across all size classes, but those

between 18 and 25 inches are significantly higher in number than most other

stands. Small snags occur primarily in the lodgepole pine component, while

snags larger than 25 inches are generally the result of mortality in red fir. Snag

heights are often higher than 50 feet, reflecting both the taller heights of red fir

and the tendency of lodgepole pine to topple as an entire tree rather than break

off. These snags are quite sound and decay classes are generally either 1 or 2.

Logs are typically less than 30 inches in large end diameter reflecting the effects

of thinning of suppressed individuals and the presence of lodgepole pine in the

stands. Lengths are commonly less than 50 feet although logs longer than this are

well represented. Logs evidence higher levels of decay than snags. The majority

of logs occur in decay classes between 3 and 5.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 239

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 13.2 2.6 2.3 0.8 0.9 0.9 20.7

Snag height (feet)

<20 6.6 - - 0.4 0.6 0.3 7.9

20-50 - - 0.4 0.3 - 0.2 0.9

>50 6.6 2.6 1.9 0.1 0.3 0.4 11.9

Snag decay class

1 - - - 0.5 - - 0.5

2 13.2 2.6 1.5 - 0.2 0.4 17.9

3 - - 0.4 0.1 0.3 0.4 1.2

4 - - 0.4 0.1 0.2 0.1 0.8

5 - - - 0.1 0.2 - 0.3

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Log length (feet)

<20 4.8 2.4 4.0 0.4 11.6

20-50 7.6 3.6 3.6 2.4 17.2

51-100 2.0 4.8 0.4 0.8 8.0

>100 0.4 1.2 0.4 - 2.0

Log decay class

1 0.4 0.4 - 0.4 1.2

2 2.8 2.0 0.4 - 5.2

3 4.4 2.4 1.6 1.2 9.6

4 5.6 5.6 3.6 0.8 15.6

5 1.6 1.6 2.8 1.2 7.2

Wildlife

These stands may offer some hiding and thermal cover to large game, but forage

possibilities appear transitory. Bolander’s bluegrass is a staple in the diet as is

Ross’ sedge and other sedges occurring in these stands. Other species occurring

on these sites are sparse or of low value for forage. The dense nature of these

stands and their location in bottom type situations, often near meadows or

streams, probably makes them valuable as hiding and thermal cover. Evidence

of deer and pocket gopher is common in these stands.

Range

These are transitional range sites that are used by livestock to access primary

forage sites such as meadows and other moist habitats. None of the more

commonly occurring species in these stands are primary or secondary forage

species, and it appears that range forage potential is low in these late seral

stands. On the other hand, signs of cattle presence is common probably due to

locations adjacent to more suitable range habitat.
240 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Management Recommendations

Many stands in this plant association have been harvested throughout the

study area. Both even-aged and uneven-aged silvicultural systems have been

tried. Although successional sequences have not been studied in detail, a notable

pattern has emerged from these past cuttings: the establishment of abundant

lodgepole pine natural regeneration after harvest. Clearcutting, heavy

improvement cuttings, or heavy selection cutting can all create the open

conditions that favor natural regeneration of lodgepole pine. Seed cone

periodicity in lodgepole pine throughout the Sierra Nevada appears to be

frequent and regular, and a steady supply of lodgepole pine seed is provided

these sites. Seed cone periodicity for other conifers, notably red and white fir, are

less frequent and probably more irregular thereby reducing the number of seed

from these species reaching a site in a given period. If residual stand densities are

kept high red fir can establish on these sites more rapidly than lodgepole pine,

and in these cases successional sequences seem to favor dominance by red fir;

however, for periods of less than 100 years lodgepole pine can often be dominant.

Many stands harvested in the past were planted to Jeffrey pine. Results are

varied and use of this practice has diminished in recent years, but Jeffrey pine

can never carry the density nor match the yields of these stands in the mix of

species usually encountered. Reforestation practices designed to regenerate these

stands with a heavier component of red fir have not been developed in detail at

this time. Most likely, strategies designed to increase the abundance of red fir

would involve planting red fir early in the reforestation sequence with thinning

at an early age to release both natural and planted red fir and control stocking of

lodgepole pine.

These stands have tremendous productive capacity and flexibility for stand

management. Stand structures are variable, and options for silvicultural systems

and cutting methods can vary to take advantage of differences in shade tolerance

and the high stand densities attainable in these stands. Natural regeneration can

be a viable option. Stand openings should be kept small and seed source near. On

north facing slopes small clearcuts can be utilized, but on south aspects

shelterwood cutting or a silvicultural system that maintains constant tree cover

is recommended. High levels of shrub, forb and grass competition are not

anticipated in most cases; however, high levels of lodgepole pine natural

regeneration should be anticipated in openings.

These sites also have the potential to contribute to wildlife values. In their

present condition they are an important source of snags especially in smaller size

classes, and through proper management, they can probably continue to provide

high levels of snags for a period of time after harvest and plantation

establishment.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 241

Red Fir-White Fir Association

Abies magnifica-abies concolor

ABMA-ABCO

CFRCFW11

Sample size: 69

Distribution

The red fir-white fir plant association is widespread in the central and southern

Sierra Nevada. Latitudes and longitudes span the study area, and samples were

located on all National Forests and Parks in the central and southern Sierra

Nevada. Stands can cover extensive areas. Individual stands can range in size

from smaller than 5 acres to a few hundred acres.

Environment

This association is located at middle and lower elevations. Average elevations

are among the lowest in these forests, and the association often identifies the

transition into the upper montane as one ascends from lower elevations. Stands

typically occur between 6,500 feet and 8,000 feet. This association reflects the

increase in elevation with decreasing latitude that is characteristic of these forests,

and stands in the south will lie at substantially higher elevations than in the

north. Aspects are varied, but northeast to northwest facing slopes are common.

The average SRI is among the lowest in these forests. Slopes range from very

gentle to quite steep, but generally they are less than 40 percent. Stands are

located on all slope positions; however, upper and middle slopes are more

common. Microrelief also varies considerably from relatively uniform

surfaces to those that are broken and hummocky. Most are somewhat uniform.

This association has significantly less bare ground and surface gravel than

most other sites. Litter cover and litter depths are substantially higher and

reflect the higher levels of tree cover and debris on the forest floor that is

characteristic of these stands.
242 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Variable Mean Range

Elevation (feet) 7,319 5,780-8,800

Slope (pct.) 26 4-57

Solar radiation index 0.469 0.351-0.575

Bare ground (pct.) 1 0-12

Surface gravel (pct.) 2 0-63

Surface rock (pct.) 5 0-45

Litter (pct.) 91 44-99

Litter depth (inches) 2.0 0.5-5.3

Stress index 0.49 0.36-0.63

Aspect: All.

Range: All.

Position: Upper and middle slopes.

Range: All.

Vegetation

Stands are dense, multilayered forests with somewhat open understories. Total

vegetative cover is high due to substantial tree cover. Overstories are

characterized by the presence of white fir in mix with red fir, and together these

two species dominate the stands.

Red fir generally was more abundant in the stands sampled, but white fir is a

prominent species that indicates the moderate site conditions found, and it can

dominate individual stands. These stands are often adjacent to and interspersed

with the white fir-sugar pine-red fir and red fir-white fir-Jeffrey pine associations

on mesic sites.

Understory shrub cover is considerably lower than most other associations

in late seral stands. Creeping snowberry and Sierra gooseberry are occasional

indicators of the moderate to moist conditions on these sites, and Sierra

chinquapin is an infrequent indicator of drier habitats. Mountain whitethorn is

an uncommon but important member of the understory due to its ability to

rapidly occupy sites after disturbance. The forb layer is composed of an

assemblage of species that normally occupy moderate to moist habitats. Thus,

white veined wintergreen, white flowered hawkweed, Kellogg’s bedstraw, and

mountain violet are indicators of middle to lower elevation mesic sites. Mountain

sweet cicely and western bracken fern frequent moist habitats. The grass layer is

sparse, but it occasionally contains Bolander’s bluegrass which also indicates the

mesic conditions on these sites.

Conifer regeneration is moderately high. Stands averaged 785 seedlings per

acre in late seral conditions, and sites regularly have more than 250 seedlings per

acre. These are typically clumped together as patches in openings. Red fir is

present on the majority of sites, and it dominates the regeneration layer. White fir

is typically present as well, but numbers are less than one-third those of red fir.

Both red fir and white fir are regenerating with significantly higher frequency

than in other associations.

Plant species diversity is moderate to low. Compared to other associations in

these forests, the total number of species is only moderate, and diversity is

influenced by the relatively low cover of shrubs, forb, and grass species that

occurs in these dense forests. Sites are dominated by two tree species that far

outweigh the cover values of the shrub, forb, and grass layers. Abundant species

are few in number and concentrated in the tree layer.

The oldest trees in these stands are commonly older than 200 years, but only

occasionally were individual trees greater than 250 years. The average age of
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 243

stands in this association is significantly younger than most others in these

forests. The oldest tree sampled was a red fir at +422 years, and the oldest white

fir was an estimated +383 years. These ages are typical of upper montane forests

in general. The reason for the relatively younger average stand ages is unclear,

but they are comparable to other low elevation plant associations. Higher

numbers of younger trees in the overstory obviously contributes to this, but the

origin of these younger trees remains somewhat obscure. It is possible that

historically higher fire frequency associated with lower elevations maintained a

substantial number of young trees in these stands.

Since stands often lie adjacent to lower montane forests where fire frequency

and intensity are considered higher, stand replacing disturbance events probably

occur more frequently than many others in the upper montane. Conversely, the

setting of many stands in this association on cooler north aspects, the structure of

the stands with open understories, and the presence of relatively large, somewhat

fire resistant individuals tend to preclude the large scale loss of all individuals

from fire. Observation of stand distributions and structure indicate stands

probably experience both small scale patchy burns and occasional large scale

stand replacing events.

Avalanche is not a common feature of most of these stands. Other disturbance

elements such as windthrow, insects, disease, and lightning are more common,

but mortality from these factors often occurs in localized situations or select

species. Disturbance from all elements appears to occur continuously on various

scales in these stands, and this results in the creation of various sized gaps with

constantly changing structures through time.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. After disturbance the most likely

successional sequence involves early dominance by shrubs, forbs, and grass.

These early communities can be quite persistent on the landscape, and

replacement by trees can be a prolonged process. Once conifer regeneration is

established, however, it grows, self-thins, and matures while other portions of

the stand continue to undergo disturbance. In time, a patchy distribution of trees

emerges with several size and tree classes, including a substantial portion of

larger trees. The stand eventually exhibits an irregular structure with many

small relatively even-aged patches distributed throughout. As stands occupy

sites for longer periods, successive disturbances continue to develop and

maintain these stand structures until an infrequent stand replacing event occurs

and a new stand emerges.

Cover (percent) Mean Range

Total vegetative 85 52-99

Tree 78 48-97

Shrub 3 0-32

Forb 13 0-80

Grass 2 0-35

Moss 0.2 0-3

Stand age (years) 192 77-319

Diversity index

Simpson 0.47 0.15-0.87

Hill numbers

N0 11.3 2.0-22.0

N1 3.36 1.32-8.56

N2 2.46 1.15-6.47
244 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

ABMA Red fir 100 55 14-90

ABCO White fir 94 25 2-71

II. Understory trees

ABMA Red fir 97 2 1-20

ABCO White fir 71 2 1-10

III. Shrubs

RIRO Sierra gooseberry 29 1 1-3

SYAC Creeping snowberry 29 4 1-25

CASE3 Sierra chinquapin 22 5 1-30

IV. Forbs

PYPI White veined wintergreen 49 1 1-3

HIAL White flowered hawkweed48 2 1-30

COMA4 Spotted coral root 43 1 1-1

KEGA Kellogg’s bedstraw 43 1 1-4

PESE3 Pine woods lousewort 43 1 1-3

PHHY Waterleaf phacelia 42 1 1-8

VIPU Mountain violet 39 2 1-30

CHBR3 Brewer’s golden aster 33 3 1-25

MOOD Mountain pennyroyal 30 1 1-5

OSCH Mountain sweet cicely 28 1 1-2

COTOW Wright’s blue eyed mary 23 2 1-10

PTAQ Western bracken fern 22 9 1-75

V. Grasses and grass-like

POBO1 Bolander’s bluegrass 26 1 1-1

Soils

Soils are predominantly Inceptisols. Entisols, Alfisols, and Mollisols are also

encountered as rare occurrences. Inceptisols are typically Xerumbrepts with

some Xerochrepts. Particle size classes are normally loamy, and indicate the

lower levels of coarse fragments in these profiles. Infrequent sites are skeletal.

Typical parent materials are granitic rocks, but occasional sites contain soils that

are derived from volcanic materials and reflect locations in the north. These soils

are commonly formed in place from bedrock. Glacial or alluvial and colluvial

deposits are encountered in few instances.

Soils in these stands are deep. Nearly 75 percent of the samples had soil depths

that exceeded 40 inches, and rarely were depths less than 35 inches. Soil textures in

both the topsoil and subsoil are usually sandy loams with occasional loams but few

sands. Subsoil textures are more often cobbly or gravelly; however, the average

coarse fragment content in both topsoil and subsoil are among the lowest of the

forested soils in the upper montane. Topsoil coarse fragments are typically less

than 15 percent, and subsoil coarse fragments are commonly less than 35 percent.

The average AWC of these sites is one of the highest in the upper montane. It

is substantially higher than most other sites, and it reflects the deep soils and

lower coarse fragments that are common to these stands. Bedrock materials are
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 245

typically fractured and rootable thereby providing access to additional stored

water. The majority of stands are well drained. Those with excess drainage are

commonly coarse textured soils on steeper slopes. Erodibility is moderate to high

in response to loamy textures or steeper slopes. Summertime soil temperatures

are cool. They are substantially lower than most other plant associations. Typical

summertime temperatures are less than 49° Fahrenheit.

Variable Mean Range

Depth of soil sample (inches) 39 19-40+

Topsoil

Depth (inches) 10 2-36

Coarse fragments (pct.) 15 1-65

pH 5.8 5.0-7.0

Subsoil

Coarse fragments (pct.) 26 5-75

pH 5.8 5.0-6.8

AWC (inches) 4.1 0.6-6.9

Temp (20 inches) (Fahrenheit) 47 37-56

Productivity

Site indexes are among the highest in the upper montane. Pacific Southwest

Region (Region 5) site indexes are typically 1 or better, and rarely are they lower

than site 2. Stand densities are also extremely high. On average, this association

has among the highest stand densities in these forests. They are exceeded only by

stands in the red fir and quaking aspen/California corn lily associations. Tree

heights are substantially higher than those in most other stands as well. This

reflects both better site indexes and the presence of white fir, which attains heights

similar to the tallest red fir. The tallest white fir in this association, for example,

was measured at 202 feet compared to the tallest red fir of 207 feet. The combination

of high site index, dense stands, and tall trees result in the highest cubic and board

foot volumes of all forested plant associations in the upper montane.

Individual stands often have the appearance of an even-aged distribution;

however, they frequently exhibit other distributions, and taken collectively stand

structures can be considered irregular. Distributions in many stands approach

those of an uneven-aged stand (fig. 40). Compared to an uneven-aged stand with

comparable stocking and a balanced diameter distribution, however, they carry

too few trees in size classes between approximately 14 and 30 inches, and they

carry too many trees in size classes larger than 30 inches. When compared to

even-aged distributions with equivalent stocking, both smaller and larger size

classes are over-represented. They closely parallel distributions of late seral

stands in the red fir plant association.

Variable Mean Range

Region 5 site index 1 0-3

Forest survey site class 2 1-4

Stand density index 520 200-948

Quadratic mean diameter 22.0 9.3-38.9

Softwood volume (mcf/ac) 15.1 5.5-29.7

Softwood volume (mbf/ac) 106.5 34.7-224.5

Softwood basal area (sq ft/ac) 372 150-627

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
246 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 65 33 1 1 - -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag numbers are moderate to high. Snags in size classes below 25 inches are

abundant, and snags in size classes larger than 25 inches are substantially more

numerous than many other associations. Mortality is concentrated most heavily

in trees between 6 and 18 inches in diameter and appears related to thinning of

smaller suppressed individuals. Mortality in larger size classes appears to be

related to senescence, and it is randomly distributed among all species. Snags are

generally shorter than 50 feet indicating a tendency of large standing snags to

break off over time. They lie predominantly between decay classes 1 and 3. Logs

are uniformly distributed between size classes. Most are shorter than 50 feet and

show higher levels of decay than snags. Decay classes 4 and 5 predominate.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 11.0 8.8 2.2 0.7 1.3 2.2 26.2

Snag height (feet)

<20 7.0 2.3 0.4 0.6 0.8 0.7 11.8

20-50 4.0 2.9 0.4 - 0.3 0.2 7.8

>50 - 3.6 1.4 0.1 0.2 1.3 6.6

Snag decay class

1 2.0 2.6 1.1 - - 0.3 6.0

2 1.0 3.4 0.4 0.2 0.2 0.5 5.7

3 8.0 2.2 0.4 0.1 0.3 0.7 11.7

4 - 0.5 - - 0.8 0.5 1.8

5 - 0.1 0.3 0.4 - 0.2 1.0

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

40

80

100

60

50

20

10

30

70

90

Figure 40—Number of trees by 110

diameter class in the red fir-white fir

plant association.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 247

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 3.3 6.7 3.3 0.7 14.0

Log length (feet)

<20 2.6 3.0 1.3 0.4 7.3

20-50 0.7 2.4 1.0 - 4.1

51-100 - 1.0 0.7 0.3 2.0

>100 - 0.3 0.3 - 0.6

Log decay class

1 -- - - -

2 - 0.7 - - 0.7

3 - - 1.3 - 1.3

4 1.3 3.7 1.7 0.3 7.0

5 2.0 2.3 0.3 0.4 5.0

Wildlife

Stands may offer hiding and thermal cover to large game, but forage possibilities

appear limited. Of the species occurring on these sites, only western bracken fern

and Bolander’s bluegrass are staples in the large game diet, and frequency of

occurrence for these species are low. Grass that comprises a major part of the

large game diets is essentially missing from this association. On the other hand,

deer presence was usually observed on these sites. Pocket gopher presence was

also common.

Range

These are transitional range sites that are used by livestock to access primary

range sites such as meadows and other moist habitats. Cattle were present in the

majority of stands, but none of the more commonly occurring species on these

sites are primary or secondary range forage species. It appears range forage

potential is low in these late seral stands.

Management Recommendations

Many stands in this association have been harvested. Early harvests were directed

at improvement cuttings, but more recently harvests in the form of clearcutting

or shelterwood to develop even-age stands have been practiced. Except in

shelterwoods, little reliance has been placed on obtaining natural regeneration.

Most sites have been planted to Jeffrey pine. Results are varied, and this practice

has diminished in recent years. Many well stocked and growing plantations are

present, but a high number of sites with low stocking and poor growth are

present as well. Poor establishment appears to result from a variety of factors not

the least of which is the role of Jeffrey pine in reforesting these sites. In the

southern portion of the study area, Jeffrey pine plantations in the range of 10 to

15 years appear to be well stocked and growing at acceptable rates. Scattered

examples are also present elsewhere in the range; however, as one travels north,

success rates appear to drop and stocking levels and growth rates become

variable. Many stands exhibit high levels of shrub and forb cover after harvest.

Original cover values for competing species are low, but through resprouting

and germination of stored seed early succession can be dominated by persistent

shrubs, such as squaw currant and bitter cherry in the south, snowbrush on the

eastside, and mountain whitethorn and Sierra chinquapin elsewhere. Bracken
248 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

fern, Anderson’s lupine, and Drew’s silky lupine within the forb component can

also dominate some of these sites. In many instances natural red and white fir

regeneration is becoming established even in plantations that are larger than 30

acres. Time periods for such regeneration may exceed 20 years, however.

These stands have very high productive capacity and flexibility for stand

management. Options for silvicultural systems and cutting methods can vary to

take advantage of the shade tolerance and high stand densities attainable in

these stands. Natural regeneration can become a viable option with proper

vegetation management practices. Stand openings should be kept small, and

reductions in stand density should anticipate an increase in shrub cover. Most

reforestation prescriptions in this type should plan for vigorous vegetation

control early in the life of any plantation. Reforestation and stand treatment such

as thinning should maintain species composition expressed in late seral stands.

Late seral stands also have the potential to contribute to wildlife values. In

their present condition they are an important source of snags especially in

smaller size classes, and through management, they can continue to provide

snags for a period of time after harvest and plantation establishment. Many of

the species that compete with conifer seedlings are also preferred or secondary

large game food sources. Thus, mountain whitethorn and bitter cherry are

preferred forage, and snowbrush is a staple in the large game diet. Careful

vegetation management early in the life of plantations can substantially increase

wildlife forage and not seriously impact reforestation efforts.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 249

Abies magnifica/arctostaphylos nevadensis

ABMA/ARNE2

CFRCFR12

Sample size: 28

Distribution

The red fir/pinemat manzanita plant association is common in the upper

montane, but it appears to be primarily a westside community. It was sampled

throughout the study area except for the Inyo National Forest. Other eastside

locations were few. Most eastside stands that are observed are the red firwestern white pine/pinemat manzanita association that resembles red fir/

pinemat manzanita to a large degree but generally lies at higher elevations. In

some areas, as near Trout Creek on the Lake Tahoe Basin Management Unit

stands can cover large acreages; however, in most cases stands are smaller than

10 acres, and many cover areas of less than an acre.

Environment

Environments in the red fir/pinemat manzanita plant association are not

substantially different from many other forested communities in the upper

montane. Elevations are wide ranging, and stands lie almost equally above and

below 8,000 feet. The lowest stand sampled was on the Eldorado National Forest,

and the highest was on the Sequoia, reflecting a characteristic rise in elevation for

these plant communities as one travels south in the range. Aspects are varied and

essentially evenly distributed across the landscape. Slopes are commonly less

than 35 percent. This association is located on all slope positions except toeslopes;

however, stands are typically found on ridge tops and upper and middle slopes.

Litter depths are significantly less than most other associations. The association

is closely related to red fir-western white pine/pinemat manzanita plant

communities in species composition, but the environments of the two, primarily

Red Fir/Pinemat Manzanita Association
250 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

elevation, soil coarse fragment content, and soil textures, differ enough that they

are classified separately at this time.

Variable Mean Range

Elevation (feet) 7,983 7,050-8,800

Slope (pct.) 24 2-47

Solar radiation index 0.498 0.361-0.584

Bare ground (pct.) 3 0-12

Surface gravel (pct.) 4 0-25

Surface rock (pct.) 10 0-45

Litter (pct.) 82 5-99

Litter depth (inches) 1.0 0.2-3.0

Stress index 0.54 0.40-0.64

Aspect: All.

Range: All.

Position: Ridges, upper slopes.

Range: Ridgetops, upper, middle, and lower slopes, benches.

Vegetation

Stands are characteristically open woodlands with a distinctive understory of

pinemat manzanita. Total vegetative cover is high due to the generally abundant

cover of pinemat manzanita, but tree cover is considerably lower than most other

associations, and trees tend to occur as scattered clumps and individuals. The

overstory is predominantly red fir; occasionally Jeffrey pine, lodgeple pine, and

white fir are present, and western white pine is sometimes present as widely

scattered individuals. Some stands in the association are actually dominated by

Jeffrey pine although red fir is typically present in these situations as well. The

presence of Jeffrey pine and white fir are indicative of the lower elevations of the

association, and they often serve to distinguish stands from the higher elevation

red fir-western white pine/pinemat manzanita association.

The shrub layer is typified by pinemat manzanita, but Sierra chinquapin is

also a consistent member of the association. Both species indicate dry conditions

in general. The forb component is often sparse and contains a mix of dry and

moderate site species. Thus, broad seeded rock cress and mountain pennyroyal

are generally indicative of drier conditions, and white veined wintergreen and

mountain violet often inhabit mesic sites. A grass layer is essentially absent.

Conifer regeneration is moderate to low, and it is usually clumped rather

than evenly distributed in the stand. Stands average 420 seedlings per acre, and

most sites contain more than 100. Occasional stands have more than 500 seedlings

per acre. Red fir dominates the regeneration layer. White fir is occasionally

present, and Jeffrey pine and western white pine are encountered in a few cases.

Red fir is regenerating significantly more often compared to other plant

associations.

Plant species diversity is moderate to low for upper montane forests. The

association has a relatively low number of species overall. Stands are dominated

by relatively few tree species and essentially a single shrub species. Together

they outweigh the cover values of the forb and grass layers. The number of

abundant species is among the lowest of any in the upper montane.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 251

The oldest trees in these stands are generally older than 250 years. Stands

contain high proportions of older trees, and average stand ages are substantially

older than dense, forested stands in the upper montane. The oldest tree sampled

was a Jeffrey pine at +663 years, and the oldest red fir was estimated at +440 years.

Although stand replacing events probably occur in this association, they do

not appear to be frequent or large scale phenomenon. The moderate slopes and

the open structure of the stands with a discontinuous, low shrub cover and

conifer stocking concentrated in relatively large, widely spaced, somewhat fire

resistant individuals, would tend to preclude stand replacing fires. Shrub layers

favor larger more intense fires, but the low growing habit of pinemat manzanita

often results in patchy burns of relatively low intensity with some portions of the

stand being consumed and others left with little damage. Isolated large trees

probably escape damage in most cases. Disturbance elements such as windthrow,

insects, disease, lightning, or avalanche do not appear to affect large areas in

these stands.

Reproductive strategies such as consistent seed production, sprouting, or

delayed germination of seed until scarified by fire is present in species on these

sites. Pinemat manzanita sprouts from stems, but it does not crown sprout.

Patchy burns would ensure survival of at least some stems and allow

reoccupation of disturbed sites. The wide spacing of existing trees would result

in uneven coverage of sites by most disturbance elements.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. Disturbance creates opportunities

for regeneration, but many microhabitats are unsuitable for conifer regeneration,

and it appears conifer establishment is a prolonged process. Disturbance provides

opportunities for surviving individuals to increase growth. Isolated patches of

conifers that escape repeated disturbance proceed through a period of crown

closure and self-thinning. Other portions of the stand continue to undergo

disturbance although there are probably always isolated trees and small patches

that escape disturbance and mature into larger individuals. In time, stands

develop an irregular structure with several age classes reflecting numerous

disturbances, and containing widely spaced large trees that are the survivors of

multiple events.

Cover (percent) Mean Range

Total vegetative 84 60-98

Tree 51 17-95

Shrub 52 2-90

Forb 6 0-70

Grass 2 0-40

Moss 0.4 0-9

Stand age (years) 268 106-523

Diversity index

Simpson 0.44 0.11-0.84

Hill numbers

N0 9.5 4.0-18.0

N1 3.57 1.34-9.72

N2 2.86 1.19-8.85
252 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

ABMA Red fir 93 44 5-90

ABCO Jeffrey pine 29 22 3-62

PIJE White fir 21 6 1-10

II. Understory trees

ABMA Red fir 89 1 1-5

ABCO White fir 25 1 1-1

III. Shrubs

ARNE2 Pinemat manzanita 100 43 1-89

CASE3 Sierra chinquapin 43 11 1-60

IV. Forbs

ARPL Broad seeded rock cress 64 1 1-30

PESE3 Pine woods lousewort 57 1 1-80

MOOD Mountain pennyroyal 43 1 1-2

CHBR3 Brewer’s golden aster 32 1 1-2

PYPI White veined wintergreen 29 1 1-1

APMEF Western dogbane 25 1 1-1

VIPU Mountain violet 21 1 1-70

V. Grasses and grass-like

None

Soils

Typical Soils are Inceptisols. In rare cases Entisols and Alfisols are encountered.

The Inceptisols usually occur as Xerumbrepts with some Xerochrepts. Entisols

are typically Orthents. Particle size classes are commonly skeletal, indicative of

higher levels of coarse fragments in the profiles. Granitic parent materials are

commonly encountered, and volcanic and metamorphic substrates are found in

rare instances. The majority of these soils are formed in place over bedrock.

Soils are moderately deep. Occasional sites have depths that exceed 40

inches, but typically depths lie between 25 and 40 inches. Coarse fragment

content in the subsoils are substantially higher than most other sites in the upper

montane. Typically they exceed 35 percent, and some are higher than 65 percent.

Topsoil textures are commonly sandy loams with occasional sands and a few

loams. Subsoil textures are more variable with a higher proportion of sands than

the topsoil and textures that are usually cobbly sandy loams with some sands

and a few loams and clay loams.

The AWC of these soils is variable. In general, sites are not substantially

different from most others. Many sites do, however, have low water holding

capacities, reflecting differences in soil textures and coarse fragment contents

within individual stands. Commonly, parent materials under these sites are

fractured and rootable, but almost as often stands occur on formations that were

massive and unrootable. These soils are excessively drained, reflecting the coarse

textures and location on slopes for most sites. Erodibility is moderate as a

consequence of the coarse soil textures and moderate to gentle slopes. Stress

indexes are characteristically high, indicative of lower AWC as well as locations

on upper slopes.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 253

Variable Mean Range

Depth of soil sample (inches) 30 (11-40+)

Topsoil

Depth (inches) 8 2-17

Coarse fragments (pct.) 25 2-75

pH 5.8 4.6-6.5

Subsoil

Coarse fragments (pct.) 49 6-80

pH 5.6 4.8-6.1

AWC (inches) 2.3 0.4-4.9

Temp (20 inches) (Fahrenheit) 51 44-62

Productivity

Site indexes vary considerably, but they are significantly lower than dense well

stocked stands elsewhere in the study area. Usually Pacific Southwest Region

(Region 5) site indexes were 4 and 5. Stand density is also considerably lower

than other forested stands in the area. Stand density indexes are typically less

than 300, and average stocking levels based on stand density index are about 55

percent of values reached in the red fir-white fir association, which is one of the

densest in these forests. Stocking also resides in the larger individuals of the

stand. The average quadratic mean diameter is among the largest in forested

associations of the upper montane. Tree heights are substantially lower than

most other sites reflecting overall lower site quality. The tallest tree measured in

this association was a Jeffrey pine at 157 feet. The tallest red fir encountered was

estimated at 152 feet, and typically heights of the tallest trees were less than 150

feet. These factors result in less basal area stocking and moderate cubic and

board foot yields for this association.

Stand structures are irregular. Stands tend to be open with few total trees per

acre, and stocking is sometimes concentrated in a few large trees (fig. 41). Stands

often appear to have an even-aged structure in the field; however, when

compared to an even-aged distribution, they have an excess of trees in both

smaller and larger size classes. Compared to an uneven-aged structure with a

balanced diameter distribution and similar stocking levels, these stands have too

few trees in size classes smaller than 18 inches, and an excess of trees in size

classes larger than 30 inches.

Variable Mean Range

Region 5 site index 3 1-5

Forest survey site class 4 2-6

Stand density index 290 118-750

Quadratic mean diameter 24.9 9.4-38.1

Softwood volume (mcf/ac) 7.1 2.9-15.7

Softwood volume (mbf/ac) 47.1 17.3-98.9

Softwood basal area (sq ft/ac) 221 72-493

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
254 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 81 4 3 9 2 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent 1 - - - - -

Coarse Woody Debris

Snag numbers are among the lowest in the upper montane. Snags in size classes

smaller than 25 inches DBH are particularly sparse, but mortality is distributed

among species in proportion to their stocking levels. Snags are distributed among

all height classes, but typically they are shorter than 50 feet reflecting a tendency

for standing snags to break off as they age. Decay classes are between 1 and 3 in

the majority of these snags. Logs are distributed among all size classes. Often

they are less than 30 inches in large end diameter, but size classes larger than 30

inches are also well represented. Logs are characteristically less than 50 feet in

length, and they indicate higher levels of decay than snags. The majority lie in

decay classes between 3 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 0 0 0.5 0.1 1.7 0.5 2.8

Snag height (feet)

<20 - - 0.2 0.1 0.3 - 0.6

20-50 - - 0.1 - 0.8 0.5 1.4

>50 - - 0.2 - 0.6 - 0.8

Snag decay class

1 - - 0.1 - 0.6 - 0.7

2 - - - - 0.3 0.5 0.8

3 - - 0.2 0.1 0.6 - 0.9

4 - - 0.1 - - - 0.1

5 - - 0.1 - 0.2 - 0.3

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

40

50

20

10

30

Figure 41—Number of trees by

diameter class in the red fir/pinemat

manzanita plant association.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 255

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 3.0 11.5 3.0 6.5 24.0

Log length (feet)

<20 2.5 6.3 1.5 3.0 13.3

20-50 0.5 3.1 1.5 3.0 8.1

51-100 - 2.1 - 0.5 2.6

>100 - - - - -

Log decay class

1 - 0.5 - 0.5 1.0

2 0.5 - - - 0.5

3 2.0 5.0 0.5 0.5 8.0

4 0.5 5.5 1.0 4.0 11.0

5 - 0.5 1.5 1.5 3.5

Wildlife

These appear to be transitional forage sites as large game seek preferred habitats.

Forage values appear to be low. None of the more common shrub and forb

species occurring on these sites contribute to the large game diet, and the grass

component is essentially absent. Nevertheless, evidence of deer and pocket

gophers were common in this association.

Range

Range forage potential appears to be transitory as livestock move to primary

range sites such as meadows and other moist habitats. The majority of sites did

show signs of cattle presence, but none of the shrub and forb species occurring

on these sites are primary or secondary range species, and the grass component

is essentially absent. It appears range forage potential is low in late seral stands

of this association.

Management Recommendations

Relatively few stands in this type have been harvested. As a result, silvicultural

systems, cutting methods, successional sequences, and stocking levels important

in the management of any forest type are relatively unknown. Where disturbance

from logging has occurred, regeneration success has been mixed. On small

scales, some success has been noted with red fir natural regeneration, but over

larger areas this is not the case. A portion of this apparent failure may result from

not applying vegetation control for pinemat manzanita or bush chinquapin.

Regeneration strategies involving planting have not been determined for this

association, and no cases were observed where stands were harvested and

planted with any systematic approach.

These stands have limited productive capacity and flexibility for stand

management. The open nature of stands indicates that regeneration and

establishment is a lengthy and variable process under most conditions.

Recommendations for harvesting at the present time would be to treat stands in

this association with caution and the expectation that results can be uncertain. A

broad base of experience in treating these stands does not exist in the field.
256 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Limited opportunities exist for salvage when it occurs, but on these open sites it

would appear that woody debris left in the form of snags and logs for wildlife or

part of the nutrient pool would be better direction for this association.

Management emphasis should provide for existing wildlife habitat, plant species

richness, and the landscape level diversity these plant communities provide to

upper montane forests.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 257

Red Fir Association

Abies magnifica

ABA

CFRCFR11

Sample size: 16

Distribution

The red fir plant association is widespread. It was sampled on all National

Forests and Parks in the study area. Latitudes and longitudes span the range of

upper montane forests in the central and southern Sierra Nevada. Red fir can be

considered the species that defines the location of upper montane forests in this

region. It appears at elevations above the white fir-sugar pine communities that

occur at the upper edge of the lower montane; it becomes dominant within the

upper montane, and it disappears gradually into the subalpine zone above.

Stands in this association are those that reflect optimum sites and maximum

development of red fir. Individual stands range from smaller than 5 acres to

extensive tracts covering large areas. Usually, however, changes in aspect,

topography, geologic formation, soil conditions, and slope position occur

frequently enough in these forests that single stands are of moderate size with

most occupying less than 100 acres.

Environment

This association can occur at all elevations of the upper montane. The lowest

stand sampled was on the Eldorado National Forest at 6,660 feet, and the highest

was at 9,240 feet on the Sequoia National Forest. Eastside stands generally occur

between elevations of 8,000 to 9,200 feet. Aspects are varied, but often northeast

and northwest aspects are encountered, and average solar radiation levels are

among the lowest in the upper montane. Slopes range from gentle to steep, but

the majority of stands occur on slopes of less than 40 percent. Stands are located

on all slope positions; however, upper, middle, and lower slopes are favored,
258 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

and seldom do they occur on ridgetops. Site microrelief varies from relatively

uniform surfaces to those that are broken and hummocky, although most are

smooth and uniform. This association has significantly lower levels of bare

ground and surface gravel than most other sites, and litter cover and litter depth

are correspondingly higher. These features reflect the substantially higher levels

of tree cover and debris on the forest floor that is characteristic of these stands.

Stress indexes are mid-range among all of the upper montane forests.

Variable Mean Range

Elevation (feet) 8,017 6,660-9,240

Slope (pct.) 24 2-60

Solar radiation index 0.475 0.293-0.587

Bare ground (pct.) 3 0-45

Surface gravel (pct.) 4 0-84

Surface Rock (pct.) 5 0-70

Litter (pct.) 87 5-99

Litter depth (inches) 1.6 0.2-5.0

Stress index 0.49 0.33-0.62

Aspect: NE, NW.

Range: All.

Position: Upper and middle slopes.

Range: All.

Vegetation

Stands are characteristically dense forests with open understories. Total tree

cover is one of the highest in the upper montane. The overstory is dominated by

a single species—red fir—and on these sites the high cover of red fir indicates the

moderate site conditions frequently encountered.

Understories are sparse. Shrub and grass layers are essentially absent. In rare

cases Sierra chinquapin, pinemat manzanita, huckleberry oak, and mountain

whitethorn may be present in substantial amounts to indicate drier site

conditions. Mountain whitethorn, often low in constancy, is an important

member of the understory due to its ability to rapidly occupy sites after

disturbance. The forb layer usually contains spotted coral root, but this is a

difficult species to recognize to an untrained eye. Occasionally white veined

wintergreen, mountain violet, or white flowered hawkweed are scattered

throughout the understory. They are also indicators of the moderate site

conditions that prevail in these stands.

Conifer regeneration is moderately high. The average number of seedlings

per acre is about 870, and most sites carry more than 100 per acre. These are

typically clumped together as patches in openings. Rare sites will have over

2,000 seedlings per acre. Red fir is the major species regenerating although white

fir, Jeffrey pine, western white pine, and lodgepole pine are infrequent members

in the regeneration layer. Red fir is regenerating on these sites with significantly

higher frequency than in other plant associations.

Plant species diversity is quite low. Stands have few species overall, and these

are concentrated in the overstory tree layer. Most sites are dominated by a single

tree species and little else. The shrub and grass layers are essentially absent, and

the tree cover far outweighs the cover values of most forb species. Abundant

species are relegated to slightly more than a single species in most stands.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 259

The oldest trees in these stands are commonly greater than 200 years. Almost

50 percent of the dominant trees sampled were older than 250 years. The oldest

tree sampled was a red fir at +531 years. Scattered individuals of other species

show ages that are comparable to ages attained in these forests in general. Thus,

the oldest white fir sampled was +341 years; the oldest Jeffrey pine was measured

at +308 years; and the oldest lodgepole pine was measured at +231years.

Stand replacing disturbances probably occur in this association, but they do

not appear to be a frequent or large scale phenomenon. The setting of many

stands on cooler north aspects, the structure of the stands with open understories,

the presence of relatively large, somewhat fire resistant individuals, and the

natural patchiness of the landscape tend to preclude large scale stand

replacement. Observation of stand distributions and structure indicate stands

probably experience both small scale patchy burns and infrequent large scale

stand replacing events.

Avalanche can replace stands on middle and lower slopes in the association,

but most appear to be infrequent and occur at scattered locations across the

landscape. Understories, including trees, generally remain intact. Other

disturbance elements such as windthrow, insects, disease, and lightning do not

appear to affect large areas in these stands. It is likely that disturbances occur

continuously on various scales, and this results in the creation of various sized

gaps with constantly changing structures through time that are quite

characteristic of these stands.

Stand development appears to be sporadic as opportunities for regeneration

and growth arise in response to disturbance. It does not appear these stands go

through a prolonged period in a grass/forb or shrub phase, although lower

elevation sites on south facing slopes can experience early dominance by

persistent shrubs and forbs such as squaw currant, mountain whitethorn, bitter

cherry, and lupine, and sometimes lodgepole pine occupies sites in abundance

after disturbance. Once regeneration is established, however, it grows, self-thins,

and matures while other portions of the stand continue to undergo disturbance.

In time, a patchy distribution of trees emerges with several size and tree classes

present including a substantial portion of larger trees. The stand eventually

exhibits an irregular structure with many small relatively even-aged patches. As

stands occupy sites for longer periods, multiple disturbances are important in

developing and maintaining structures until the site does encounter a stand

replacing event, and a new stand emerges.

Cover (percent) Mean Range

Total vegetative 82 40-90

Tree 77 29-96

Shrub 2 0-26

Forb 6 0-90

Grass 1 0-46

Moss 0.2 0-8

Stand age (years) 219 79-446

Diversity index

Simpson 0.78 0.16-1.00

Hill numbers

N0 7.9 1.0-20.0

N1 1.88 1.00-8.26

N2 1.42 1.00-6.41
260 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Characteristic Vegetation

Percent cover

 Code Common name Constancy Mean Range

I. Overstory trees

ABMA Red fir 100 76 28-99

II. Understory trees

ABMA Red fir 95 4 0-75

III. Shrubs

None

IV. Forbs

COMA4 Spotted coral root 48 1 1-2

PESE3 Pine woods lousewort 47 1 1-20

PHHY Waterleaf phacelia 43 1 1-80

PYPI White veined wintergreen 36 1 1-5

VIPU Mountain violet 32 1 1-30

ARPL Broad seeded rock cress 30 1 1-6

HIAL White flowered hawkweed 29 1 1-3

CHBR3 Brewer’s golden aster 26 2 1-10

V. Grasses and grass-like

None

Soils

Soils are typically Inceptisols, and usually classified as Xerumbrepts with

occasional Xerochrepts. Occasional Entisols and rare Alfisols are also

encountered. Entisols are evenly distributed between Orthents and Psamments

at the suborder level, and the few Alfisols are represented by Xeralfs. Particle

size classes are usually skeletal, reflective of somewhat higher levels of rock

fragments throughout the profile. Occasional sites are classified as loamy.

Granitic parent materials occur most often, but volcanic substrates are not

uncommon, and represent samples from the northern portion of the study area.

Soils derived from metamorphic, sedimentary, and mixed lithology are rare.

Soils in this association are typically formed in place from bedrock although

occasional soils are developed from deposited materials such as glacial till,

colluvium, or alluvium.

Soils are quite deep. Average depths are considerably deeper than most

other sites. Depths exceeded 40 inches on over two-thirds of the sample sites.

Rare sites had depths less than 35 inches. Topsoil and subsoil textures are nearly

identical. They are usually sandy loams. Occasional sands or loams occurred that

differed from this modal texture, and subsoils had a tendency toward higher

levels of sand. In general, these soils can be considered moderately coarse

textured throughout the profile. Coarse fragment contents in the topsoil are

generally less than 35 percent. Subsoils contain higher levels overall, but they are

often less than 35 percent as well.

The AWC of these stands is somewhat variable, but it can be considered

moderate in most cases. This reflects coarser textures in many of these soils

contrasting with the deeper soils commonly encountered. Bedrock conditions

below lithic contacts show variable rooting conditions, but they are usually

fractured and rootable, thereby increasing the available water supply. Typically,

these soils are well drained, although sites with coarser textured soils and

steeper slopes can sometimes be excessively drained. Erodibility ranges widely
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 261

from low to high, reflecting differences in soil texture and slope on individual

sites. Summertime soil temperatures are cool. They are significantly lower than

in most other plant associations in the upper montane, and typically they lie

below 49° Fahrenheit.

Variable Mean Range

Depth of soil sample (inches) 38 18-40+

Topsoil

Depth (inches) 8 2-25

Coarse fragments (pct.) 20 0-98

pH 5.9 4.5-7.0

Subsoil

Coarse fragments (pct.) 38 0-99

pH 5.8 4.5-7.5

AWC (inches) 3.3 0.7-6.5

Temp (20 inches) (Fahrenheit) 47 36-60

Productivity

Pacific Southwest Region (Region 5) site indexes average 2 in these stands, but

they show considerable variation, reflecting the range of environments occupied.

Typically, however, site indexes are 2 or better, and only rarely are they as low as

4. Stand density is quite high. Stands regularly have stand density indexes that

exceed 500. Index values in the densest stands measured were over 1,100, which

corresponds to values from earlier studies (Reineke 1933). On average, these are

some of the densest stands in the upper montane. Quadratic mean diameters are

also among the largest in these forests and reflect substantial stocking in large

trees. Tree heights are substantially taller than those in most other stands as well.

On the best sites, red fir can attain impressive heights. The tallest red fir was

measured at 232 feet in this association. Yields are also high. The combination of

relatively high site index, dense stands, and tall trees results in average cubic and

board foot yields in these late seral stands that are among the highest of the

upper montane forests.

Many individual stands appear to be even-aged; however, on any scale

larger than a few acres structures approach the irregular distributions

characteristic of other dense late seral stands in upper montane forests (fig. 42).

Considered collectively, structures approach those of uneven-aged stands.

Compared to an uneven-age distribution with similar stocking levels and a

balanced diameter distribution, these stands generally contain too few trees in

size classes smaller than 24 inches and too many in size classes larger than 30

inches. When compared to an even-age distribution, they carry too many trees in

both smaller and larger size classes.

Variable Mean Range

Region 5 site index 2 0-4

Forest survey site class 3 1-5

Stand density index 517 136-1104

Quadratic mean diameter 24.7 8.4-39.4

Softwood volume (mcf/ac) 15.0 2.8-30.5

Softwood volume (mbf/ac) 105.9 17.9-225.1

Softwood basal area (sq ft/ac) 402 93-693

Hardwood volume (mcf/ac) 0 0

Hardwood basal area (sq ft/ac) 0 0
262 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Tree species composition by percent of basal area

Species ABMA ABCO PICO PIJE PIMO3 TSME

Percent 96 2 1 - 1 -

Species JUOC PILA LIDE3 PIAL POTR QUKE

Percent - - - - - -

Coarse Woody Debris

Snag numbers are moderate when compared to other associations. Snags less

than 18 inches DBH are abundant, and those in size classes larger than 25 inches

are substantially more numerous than in most other stands. Mortality in smaller

individuals represents losses to thinning of suppressed individuals; whereas in

the larger members of the stand it is probably related to senescence, and it is

distributed rather uniformly among the larger size classes. The majority of snags

occurring in this association are red fir. Snag heights are distributed among all

classes, but typically they are shorter than 50 feet, reflecting a tendency of large

standing snags to break off with the passage of time. They are relatively sound

and generally lie in decay classes between 1 and 3. Logs are commonly smaller

than 30 inches in large end diameter, although logs larger than 30 inches are also

well represented. Lengths are predominantly less than 50 feet, and logs evidence

more decay than snags. The majority lie in decay classes between 3 and 5.

Snags

Breast Height Diameter Class (inches)

<11 11-17.9 18-24.9 25-29.9 30-39.9 >40 Total

Snags per acre 4.4 3.1 2.5 1.3 1.4 1.9 14.6

Snag height (feet)

<20 1.4 0.8 1.1 0.4 0.7 1.0 5.4

20-50 2.7 1.3 0.4 0.6 0.4 0.3 5.7

>50 0.3 1.0 1.0 0.3 0.3 0.6 3.5

Snag decay class

1 0.9 0.7 0.3 0.3 0.2 0.2 2.6

2 2.7 1.3 0.5 0.1 0.3 0.5 5.4

3 0.8 1.0 1.3 0.7 0.8 0.6 5.2

4 - 0.1 0.4 0.2 0.1 0.4 1.2

5 - - - - - 0.2 0.2

Diameter class

Trees per acre

1–11 12–18 19–25 26–30 GT 40 31–39

0

40

50

60

70

80

20

10

30

Figure 42—Number of trees by

diameter class in the red fir plant

association.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 263

Logs

Large End Diameter Class (inches)

11-20 21-30 31-40 >40 Total

Logs per acre 12.3 12.2 6.6 5.1 36.2

Log length (feet)

<20 6.5 5.7 2.9 1.8 16.9

20-50 5.0 4.3 2.5 2.1 13.9

51-100 0.8 2.2 1.0 0.9 4.9

>100 - - 0.2 0.3 0.5

Log decay class

1 - 0.1 - 0.1 0.2

2 2.1 0.6 0.3 0.3 3.3

3 5.6 4.3 1.8 1.0 12.7

4 3.9 4.0 2.6 2.6 13.1

5 0.7 3.2 1.9 1.1 6.9

Wildlife

Stands may offer some hiding and thermal cover to large game, but forage

possibilities appear sparse. Of the species commonly occurring on these sites

only waterleaf phacelia appears to be a staple that occurs with sufficient

constancy to contribute to the large game diet. Shrubs and grass that comprise a

major part of large game diets are essentially missing from this plant association.

On the other hand, deer and pocket gopher presence was commonly observed in

these stands.

Range

These are transitional range forage sites that are used by livestock to access

primary forage areas such as meadows and other moist habitats. None of the

more commonly occurring species on these sites, however, are of value as

primary or secondary range forage; and grass, which forms a major portion of

the range diet, is essentially missing from this association. Signs of cattle use

were present in the majority of cases, but forage potential for livestock is generally

low in late seral stands.

Management Recommendations

Many stands have been harvested in the study area. Early harvests were directed

at improvement cuttings, but more recently harvests in the form of clearcutting

and shelterwood to develop even-age stands have been practiced. One

observation can be made from this early cutting. If seed sources are left on or

adjacent to these sites, they will eventually regenerate naturally with red fir. In

past cases involving clearcutting, most sites were planted with Jeffrey pine.

Results in general from this approach are mixed, and this practice has diminished

in recent years. Stocking levels were erratic and growth rates were low. On the

other hand, many of these sites have regenerated naturally with red fir,

apparently because of erratic seed production from residual trees and adjacent

stands. This can take some time, perhaps as long as 25 years. Rather sizeable

clearcuts (25+ acres) appear to have been regenerated in this way. In cases

involving shelterwood cutting, good results have been observed in some cases,
264 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

but this practice is still new in this portion of the Sierra Nevada, and broad

patterns are not well established at this time. More recently, regeneration

strategies involving planted red fir are being used. Nursery practices and

planting techniques have been developed, but survival rates are somewhat

erratic at this point, and more time must pass before judgments can be made

about this practice.

Late seral stands on these sites generally do not carry high levels of shrub

and forb cover, particularly on north aspects or at higher elevations; however, in

individual cases shrub, forb, and grass competition can become significant after

treatment. The ability to predict these situations at this time is not good; however,

south aspects should be approached with caution. Early successional sequences

in these stands are not well understood at present.

These stands have high productive capacity and flexibility for stand

management. Options for silvicultural systems and cutting methods can vary to

take advantage of the shade tolerance and high stand densities attainable in

these stands. Natural regeneration can be a viable option. Stand openings should

be kept small and seed source near. On north facing slopes small clearcuts can be

used, but on south aspects shelterwood cutting or a silvicultural system that

maintains constant tree cover is recommended. If shelterwood cutting is used,

care must be directed to selection of seed trees. In many cases in the past,

shelterwood residuals were composed of trees too young to bear many cones, or

trees with damaged and unproductive crowns. High levels of shrub, forb and

grass competition are not anticipated in most cases; however, individual sites,

particularly at lower elevations and south aspects, can become occupied with

species such as mountain whitethorn that offer serious competition to new

seedlings.

Stands in this association also have the potential to contribute to wildlife

values. In their present condition they are an important source of snags especially

in smaller size classes, and through management, they can continue to provide

snags for a period of time after harvest and plantation establishment.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 265 Appendix A Classification Hierarchy of Plant Associations Plant Association Subseries Series Bolander’s Locoweed (Astragalus bolanderii) Bolander’s Locoweed Bolander’s Locoweed ASBO1, FBLFBL112 Red Fir/Mountain Mule Ears (Abies magnifica/Wyethia mollis) Red Fir/MountainMule Ears Red Fir ABMA/WYMO, CFRFME11 Quaking Aspen/California Corn Lily (Populus tremuloides/Veratrum Californicum) Quaking Aspen Quaking Aspen POTR/VECA1, HQAHQA11 Quaking Aspen/Mountain Pennyroyal (Populus tremuloides/Monardella odoratissima) Quaking Aspen Quaking Aspen POTR/MOOD, HQAHQA12 Western Juniper/Sagebrush (Juniperus occidentalis/Artemisia tridentata) Western Juniper Western Juniper JUOC/ARTR, CJOCJO12 Western Juniper (Juniperus occidentalis) Western Juniper Western Juniper JUOC, CJOCJO11 Mountain Hemlock//Steep (Tsuga mertensiana//steep) Mountain Hemlock Mountain Hemlock TSME//STEEP, CHMCHM11 Mountain Hemlock (Tsuga mertensiana) Mountain Hemlock Mountain Hemlock TSME, CHMCHM12 Jeffrey Pine/Huckleberry Oak (Pinus Jeffreyii/Quercus vaccinifolia) Jeffrey Pine Jeffrey Pine PIJE/QUVA, CPJCPJ12
266 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Plant Association Subseries Series Jeffrey Pine/Greenleaf Manzanita-Snowbrush (Pinus Jeffreyii/ Jeffrey Pine Jeffrey Pine Arctostaphylos patula-Ceanothus velutinus) PIJE/ARPA9-CEVE3, CPJCPJ13 Jeffrey Pine/Mountain Whitethorn-Sagebrush (Pinus Jeffreyii/Ceanothus Jeffrey Pine Jeffrey Pine cordulatus-Artemisia tridentata) PIJE/CECO2-ARTR, CPJCPJ14 Jeffrey Pine-Red Fir (Pinus Jeffreyii-Abies magnifica) Jeffrey Pine Jeffrey Pine PIJE-ABMA, CPJCPJ11 Lodgepole Pine/Gray’s Lovage (Pinus contorta/Ligusticum grayii) Lodgepole Pine Lodgepole Pine PICO/LIGR1, CPLCPL11 Lodgepole Pine/Sagebrush (Pinus contorta/Artemisia tridentata) Lodgepole Pine Lodgepole Pine PICO/ARTR, CPLCPL14 Lodgepole Pine//Woodlands (Pinus contorta//woodlands) Lodgepole Pine Lodgepole Pine PICO//WOODLANDS, CPLCPL12 Lodgepole Pine (Pinus contorta) Lodgepole Pine Lodgepole Pine PICO, CPLCPL13 Red Fir-Western WhitePine/Sierra Chinquapin (Abies magnifica-Pinus monticola/ Red Fir-Western White Pine Red Fir Castanopsis sempervirens) ABMA-PIMO3/CASE3, CFRCPW14 Red Fir-Western WhitePine/Pinemat Manzanita (Abies magnifica-Pinus monticola/ Red Fir-Western White Pine Red Fir Arctostaphylos nevadensis) ABMA-PIMO3/ARNE2, CFRCPW12
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 267 Plant Association Subseries Series 1 See appendix I for the key to species codes. See “Using the Classification” in the text for an explanation of the use of slashes and hyphens. 2 Assigned by the U.S. Department of Agriculture, Forest Service, Pacific Southwest Region Ecology Program. Red Fir-Western WhitePine-Lodgepole Pine (Abies magnifica-Pinus monticola-Pinus contorta) Red Fir-Western White Pine Red Fir ABMA-PIMO3-PICO, CFRCPW13 Red Fir-Western WhitePine (Abies magnifica-Pinus monticola) Red Fir-Western White Pine Red Fir ABMA-PIMO3, CFRCPW11 White Fir-Sugar Pine-Red Fir (Abies concolor-Pinus lambertiana-Abies magnifica) White Fir-Sugar Pine White Fir ABCO-PILA-ABMA, CFWCPR11 Red Fir-White Fir-Jeffery Pine (Abies magnifica-Abies concolor-Pinus Jeffreyii) Red Fir-White Fir Red Fir ABMA-ABCO-PIJE, CFRCFW12 Red Fir-White Fir (Abies magnifica-Abies concolor) Red Fir-White Fir Red Fir ABMA-ABCO, CFRCFW11 Red Fir-Lodgepole Pine/White Flowered Hawkweed Red Fir-Lodgepole Pine Red Fir (Abies magnifica-Pinus contorta/Hieracium albiflorum) ABMA-PICO/HIAL, CFRCPL11 Red Fir/Pinemat Manzanita (Abies magnifica/Arctostaphylos nevadensis) Red Fir Red Fir ABMA/ARNE2, CFRCFR12 Red Fir (Abies magnifica) Red Fir Red Fir ABMA, CFRCFR11
268 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Appendix B Soil Taxonomy by Plant Association Soil Taxonomy Plant Association1 POTR/ POTR/ JUOC/ ABMA/ TSME// ASBO MOOD VECA1 ARTR JUOC WYMO STEEP Order Great Group (10)2 (19) (16) (17) (12) (14) (17) Inceptisols Xerumbrepts 6 8 11 10 2 8 5 Cryumbrepts 3 4 5 4 4 2 Haplumbrepts Xerochrepts 3 1 4 3 Cryochrepts 3 Durochrepts Dystrandepts Vitrandepts Humaquepts Entisols Xerorthents Cryorthents 2 Cryofluvents Udifluvents 1 Xeropsamments 1 2 Cryopsamments Cryaquents Mollisols Cryoborolls 1 Paleborolls Haploxerolls 2 Alfisols Haploxeralfs 1 2 2 Cryoboralfs 2 1 2
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 269 Soil Taxonomy Plant Association1 ABMA- ABMA- ABMA- ABCO- PIMO3/ PIMO3/ PIMO3- ABMA- PILA- PIJE/ TSME ARNE2 CASE3 PICO PIMO3 ABMA QUVA Order Great Group (32) (31) (11) (25) (35) (33) (32) Inceptisols Xerumbrepts 8 6 1 2 10 16 19 Cryumbrepts 5 2 5 2 Haplumbrepts 3 Xerochrepts 5 7 1 2 13 10 3 Cryochrepts 3 1 2 1 Durochrepts Dystrandepts 1 Vitrandepts Humaquepts Entisols Xerorthents 2 4 5 5 2 3 Cryorthents 1 5 2 3 1 2 Cryofluvents 1 Udifluvents Xeropsamments 3 6 3 1 2 1 3 Cryopsamments 1 3 1 Cryaquents Mollisols Cryoborolls 1 Paleborolls Haploxerolls Alfisols Haploxeralfs 3 1 1 4 1 Cryoboralfs
270 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Soil Taxonomy Plant Association1 PIJE/ PIJE/ ABMA- ARPA9- CECO2- ABCO- PIJE- PICO/ PICO/ PICO// CEVE3 ARTR PIJE ABMA ARTR LIGR1 WDLNDS Order Great Group (32) (18) (31) (8) (11) (23) (10) Inceptisols Xerumbrepts 12 8 16 4 7 1 Cryumbrepts 2 1 2 1 Haplumbrepts 1 Xerochrepts 3 2 10 1 6 2 Cryochrepts Durochrepts Dystrandepts Vitrandepts Humaquepts 1 Entisols Xerorthents 7 1 4 1 1 1 Cryorthents 2 1 2 2 1 Cryofluvents Udifluvents Xeropsamments 5 3 1 4 4 Cryopsamments 1 1 1 Cryaquents 1 Mollisols Cryoborolls 1 Paleborolls Haploxerolls 2 1 1 Alfisols Haploxeralfs 2 1 Cryoboralfs 1
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 271 Soil Taxonomy Plant Association1 ABMA- PICO/ ABMA- ABMA/ PICO HIAL ABCO ARNE2 ABMA Order Great Group (8) (48) (69) (28) (167) Inceptisols Xerumbrepts 1 16 35 12 84 Cryumbrepts 1 1 1 2 Haplumbrepts Xerochrepts 1 15 22 9 45 Cryochrepts 1 Durochrepts 1 Dystrandepts 1 Vitrandepts 1 Humaquepts Entisols Xerorthents 1 3 5 11 Cryorthents 2 4 7 Cryofluvents Udifluvents Xeropsamments 1 5 4 1 11 Cryopsamments 1 1 4 Cryaquents Mollisols Cryoborolls 1 Paleborolls 1 1 Haploxerolls 1 1 Alfisols Haploxeralfs 1 1 1 2 Cryoboralfs 1 See appendix A for a list of associations and codes. 2 Number of samples.
272 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Appendix C

Variables Used in the Classification

Definitions of variables may be found in the list of references. Definitions for location, environment, soil,

and vegetation can be found in the Ecosystem Classification and Inventory Handbook, FSH 2090.11 (U.S.

Department ofAgriculture 1991). Definitions for productivity can be found in this same reference and the

Forest Inventory and Analysis User’s Guide (U.S. Department of Agriculture 1992).

Location: _______________________________________________________________________________

• Plot identification • National Forest or Park and Ranger District

• Forest map number • Local planning compartment

• Township • Range

• Section

Environment:____________________________________________________________________________

• Elevation (feet) • Aspect (Azimuth)

• Slope (percent) • Landform

• Slope position • Horizontal microrelief

• Vertical microrelief • Percent of bare ground

• Percent of gravel • Percent of surface rock

• Total vegetative cover (percent) • Age of vegetation

• Percent of moss • Percent litter

• Litter thickness (inches) • Total tree basal area (square feet per acre)

• Latitude (degrees and minutes) • Longitude (degrees and minutes)

• Fire evidence (presence/absence) • Insects and disease (presence/absence)

• Grazing (presence/absence) • Logging (presence/absence)

• Wildlife (presence/absence)

Soil:____________________________________________________________________________________

• Type of parent material • Parent material origin

• Total soil depth (inches)1 • Rootability

• Topsoil thickness (inches) • Topsoil texture

• Topsoil coarse fragment content (percent) • Topsoil color

• Subsoil texture • Subsoil coarse fragment content (percent)

• Subsoil color • Soil drainage class

• Available water holding capacity (AWC) (inches) • Soil name

• Topsoil pH • Subsoil pH

• Soil temperature (degrees Fahrenheit)2

1Soil depth was measured from the mineral surface to bedrock, or a layer of material that is impenetrable to roots, or a maximum of

40 inches—whichever was deepest.

2Summertime temperature measured at 20-inch depth.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 273

Tree Layer: _____________________________________________________________________________

• Overstory tree species • Overstory cover by species (percent)

• Total tree cover (percent) • Diameter group

• Dominant height (feet) • Stand age (years)3

• Canopy position of tree species • Understory tree species

• Understory cover by species (percent) • Understory density by species

Shrub Layer: ____________________________________________________________________________

• Shrub species • Shrub cover by species (percent)

• Total shrub cover (percent) • Average height of shrubs by species

Herbaceous Layer: _______________________________________________________________________

• Forb species • Forb cover by species (percent)

• Total forb cover (percent) • Forb abundance by class

Grass and Grass-like Layer: _______________________________________________________________

• Grass and grass-like species • Grass and grass-like cover by species

(percent)

• Total grass and grass-like cover (percent) • Grass and grass-like abundance by class.

Productivity: ____________________________________________________________________________

• Pacific Southwest Region site index • Forest survey site class

• Number of trees per acre • Stand density index4

• Quadratic mean diameter • Basal area (square feet per acre)

• Cubic foot volume (MCF) • Board foot volume (MBF-Scribner)

Coarse Woody Debris: ____________________________________________________________________

• Species of snag • Snag diameter at breast height

• Snag height • Snag decay class

• Species of log • Log diameter at large end

• Log diameter at small end • Log length

• Log decay class

Derived Variables: _______________________________________________________________________

• Solar radiation index (SRI) • Simpson’s index of diversity.

• Hill diversity numbers • Stress index = ((SRI)*0.25)+((AWC/

10)*0.25)+((10000-ELEV/9000)* 0.25)

+((POSN)* 0.25) in which position was

assigned an ordinal value based on

seven slope positions from ridgetop to

draw including benches.

3Stand ages are the average ages of three or more dominant trees at each sample site.

4Reinecke 1993.
274 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Appendix D

Autecological Relationships of Selected Plants

Plant species on a site are often referred to as indicator or characteristic species

because of their particular relationship to environmental conditions. In many

studies these relationships are established from published documents(Abrams

and Ferris 1975, Burns and Honkala 1990, Hickman 1993, McMinn 1939, Minore

1979, Munz and Keck 1959) or from observations made in the field during

sampling. Such relationships were explored in further detail in this study by

using information obtained from the samples to establish the autecological status

of many plants in the upper montane.

The observations offered here are not intended to fully describe the

environmental relationships of all species sampled. Rather, they emphasize most

of the indicator species used in the classification and a few others that are

characteristic of particular settings. The table highlights the environmental

differences on sites containing each of the selected species. Environmental

settings that are not substantially different from the distributions obtained on

other sites in the upper montane are not described. These observations are

intended to assist those using the classification in understanding and interpreting

site conditions based upon floristic composition. Species have been stratified on

the basis of moisture relationships that may be useful in management, and

entries under each moisture regime are listed in order of life form: trees, shrubs,

forbs, and grass.
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 275 Autecological Relationships of Selected Plants –––––––––––––––––––––––––––––––––––––––––––––––––– Dry Site Indicators –––––––––––––––––––––––––––––––––––––––– Feature ------------------------------------------------------------ Trees ----------------------------------------------------------- Juniperus occidentalis Pinus Jeffreyii Pinus monticola Physiognomy of typical community open, shrubby woodland open, shrubby forest ~ Distribution north, eastside ~ ~ Elevation middle, high ~ high Solar radiation index high ~ low Aspect se, sw se, sw ne, nw Position ~ ~ upper slopes, ridges Slope ~ ~ ~ Microrelief hummocky, broken hummocky, broken hummocky, undulating Litter thickness ~ ~ ~ Bare ground high high ~ Gravel high high ~ Rock high ~ high Tree cover low low moderately low Shrub cover high high ~ Forb cover high ~ high Grass cover high ~ ~ Total basal area low low ~ Stand density low low ~ R-5 Site class low low ~ Parent material ~ granite, ash, tephra ~ Parent material origin ~ glacial outwash, alluvium ~ Total soil depth moderately shallow shallow ~ Surface horizon depth deep ~ shallow Surface horizon texture ~ coarse ~ Subsoil texture ~ coarse: gravelly ~ Surface coarse fragments high ~ ~ Subsoil coarse fragments high ~ high Rootability ~ hard, fractured, massive ~ Drainage ~ excessive excessive Available water holding capacity low low low Moisture stress high high ~ Soil acidity ~ ~ ~ Soil temperature high high ~ Soil taxonomy ~ ~ entisols Soil particle size class ~ ~ ~
276 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Autecological Relationships of Selected Plants –––––––––––––––––––––––––––––––––––––––– Dry Site Indicators –––––––––––––––––––––––––––––––––––––––– Feature ----------------------------------------------------------- Shrubs ---------------------------------------------------------- Arctostaphylos nevadensis Arctostaphylos patula Castanopsis sempervirens Physiognomy of typical community open, shrubby forest open, shrubby forest shrubby forest Distribution north ~ south Elevation ~ ~ ~ Solar radiation index high high high Aspect se, sw se, sw se, sw Position ~ ~ upper, middle slopes Slope ~ ~ steep, >40 percent Microrelief ~ ~ hummocky, broken Litter thickness shallow ~ ~ Bare ground high high low Gravel high high ~ Rock high ~ high Tree cover low low ~ Shrub cover ~ high ~ Forb cover low ~ ~ Grass cover ~ ~ ~ Total basal area low low low Stand density ~ ~ ~ R-5 Site class low low low Parent material ~ ~ Granite Parent material origin ~ ~ ~ Total soil depth shallow ~ ~ Surface horizon depth ~ ~ shallow Surface horizon texture ~ moderately coarse, coarse ~ Subsoil texture ~ moderately coarse, coarse coarse: sandy Surface coarse fragments ~ high high, gravelly, cobbly Subsoil coarse fragments high high, gravelly, stoney ~ Rootability hard, fractured, massive ~ ~ Drainage excessive excessive excessive Available water holding capacity low low low Moisture stress high high high Soil acidity ~ ~ ~ Soil temperature high high ~ Soil taxonomy ~ entisols entisols Soil particle size class skeletal skeletal, sandy skeletal, sandy
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 277 Autecological Relationships of Selected Plants –––––––––––––––––––––––––––––––––––––––– Dry Site Indicators –––––––––––––––––––––––––––––––––––––––– Feature ----------------------------------------------------------- Shrubs ---------------------------------------------------------- Quercus vaccinifolia Ceanothus velutinus Prunus emarginata Physiognomy of typical community open, shrubby forest open, shrubby forest open, shrubby forest Distribution north, westside north, eastside ~ Elevation middle, low ~ ~ Solar radiation index high ~ high Aspect se, sw ~ se, sw Position ~ ~ upper, middle slopes Slope ~ steep, >40 percent moderately steep Microrelief hummocky, broken ~ ~ Litter thickness ~ ~ ~ Bare ground high high high Gravel high high high Rock high ~ high Tree cover low low low Shrub cover high high high Forb cover ~ ~ ~ Grass cover ~ ~ ~ Total basal area low low low Stand density ~ ~ ~ R-5 Site class low ~ ~ Parent material granite ~ ~ Parent material origin ~ alluvium, colluvium ~ Total soil depth ~ ~ moderately shallow Surface horizon depth ~ ~ ~ Surface horizon texture ~ coarse: sandy ~ Subsoil texture ~ coarse: sandy ~ Surface coarse fragments high, gravelly, cobbly ~ ~ Subsoil coarse fragments gravelly, cobbly gravelly, cobbly high, cobbly Rootability ~ ~ ~ Drainage excessive excessive excessive Available water holding capacity low low low Moisture stress high ~ high Soil acidity ~ neutral ~ Soil temperature ~ high high Soil taxonomy ~ entisols ~ Soil particle size class ~ sandy ~
278 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Autecological Relationships of Selected Plants –––––––––––––––––––––––––––––––––––––––– Dry Site Indicators –––––––––––––––––––––––––––––––––––––––– Feature ------------------------------------------------------------ Forbs ----------------------------------------------------------- Eriogonum nudum Arabis platysperma Monardella odoratissima Physiognomy of typical community open, shrubby forest open forest open, shrubby forest Distribution ~ ~ ~ Elevation high high ~ Solar radiation index high ~ high Aspect se, sw ~ se, sw Position ~ upper slopes, ridges ~ Slope ~ ~ ~ Microrelief undulating undulating ~ Litter thickness shallow shallow shallow Bare ground high high high Gravel high high high Rock ~ moderately high ~ Tree cover low low low Shrub cover high low high Forb cover high ~ high Grass cover high low high Total basal area low low low Stand density ~ ~ low R-5 Site class ~ low ~ Parent material volcanics ~ ~ Parent material origin ~ ~ ~ Total soil depth ~ moderately shallow moderately shallow Surface horizon depth ~ shallow ~ Surface horizon texture coarse: sandy coarse: sandy ~ Subsoil texture coarse: sandy coarse: sandy ~ Surface coarse fragments high, gravelly, cobbly moderately high high, gravelly, cobbly Subsoil coarse fragments ~ high high, gravelly, cobbly Rootability ~ fractured ~ Drainage excessive excessive ~ Available water holding capacity low low ~ Moisture stress ~ high high Soil acidity ~ ~ ~ Soil temperature high ~ high Soil taxonomy entisols ~ inceptisols Soil particle size class ~ ~ ~
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 279 Autecological Relationships of Selected Plants –––––––––––––––––––––––––––––––––––––––––––––––––– Dry Site Indicators –––––––––––––––––––––––––––––––––––––––– Feature ------------------------------------- Forbs --------------------------------- --- Grass and Grass-like -- Calyptridium umbellatum Gayophytum eriospermum Sitanion hystrix Physiognomy of typical community open forest open forest open forest Distribution ~ ~ ~ Elevation ~ ~ high Solar radiation index high high high Aspect se, sw se, sw se, sw Position upper slopes, ridges upper slopes, ridgetops upper slopes, ridgetops Slope ~ ~ ~ Microrelief undulating hummocky undulating Litter thickness shallow shallow shallow Bare ground high high high Gravel high high high Rock ~ ~ high Tree cover moderately low low low Shrub cover ~ moderately high high Forb cover moderately high high high Grass cover moderately high moderately high high Total basal area low low low Stand density low ~ low R-5 Site class low ~ low Parent material ~ ~ ~ Parent material origin ~ ~ ~ Total soil depth ~ ~ moderately shallow Surface horizon depth ~ ~ deep Surface horizon texture coarse: sandy ~ ~ Subsoil texture coarse: sandy ~ ~ Surface coarse fragments ~ gravelly, cobbly moderately high Subsoil coarse fragments ~ gravelly, cobbly ~ Rootability ~ ~ hard, fractured, massive Drainage excessive excessive excessive Available water holding capacity ~ excessive low Moisture stress high high ~ Soil acidity ~ acid ~ Soil temperature high high high Soil taxonomy ~ ~ mollisols Soil particle size class sandy ~ ~
280 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Autecological Relationships of Selected Plants ––––– Dry Site Indicators –––– ––––––––––––––––––– Moderate Site Indicators ––––––––––––––––––– Feature ----- Grass and Grass-like ------ ------------------------------------ Trees ------------------------------------- Stipa occidentalis Abies magnifica Abies concolor Physiognomy of typical community ~ dense forest dense forest Distribution eastside ~ ~ Elevation high ~ middle, low Solar radiation index ~ ~ ~ Aspect ~ ~ ~ Position upper slopes, ridges, benches ~ ~ Slope ~ ~ ~ Microrelief undulating uniform, undulating ~ Litter thickness shallow ~ deep Bare ground ~ low low Gravel ~ low low Rock ~ ~ ~ Tree cover low high high Shrub cover high low ~ Forb cover high low ~ Grass cover high low low Total basal area low high ~ Stand density ~ high ~ R-5 Site class low high ~ Parent material ~ ~ ~ Parent material origin alluvium bedrock ~ Total soil depth moderately shallow deep deep Surface horizon depth ~ ~ ~ Surface horizon texture coarse: sandy moderately coarse: loamy moderately coarse: loamy Subsoil texture ~ moderately coarse: loamy loamy Surface coarse fragments ~ ~ ~ Subsoil coarse fragments ~ ~ low Rootability fractured ~ ~ Drainage excessive well well Available water holding capacity low high high Moisture stress ~ ~ ~ Soil acidity ~ ~ acid Soil temperature high ~ ~ Soil taxonomy entisols inceptisols ~ Soil particle size class skeletal, sandy ~ ~
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 281 Autecological Relationships of Selected Plants ––––––––––––––––––––––––––––––––––––– Moderate Site Indicators –––––––––––––––––––––––––––––––––––––– Feature ----------------------------- Trees --------------------------------- ------- Shrubs ------ Pinus contorta Tsuga mertensiana Ceanothus cordulatus Physiognomy of typical community open to dense forest dense forest open, shrubby forest Distribution ~ north ~ Elevation middle, high high low Solar radiation index ~ low high Aspect ~ ne, nw se, sw Position lower slopes, toeslopes, benches upper slopes ~ Slope shallow moderately steep moderate Microrelief ~ ~ ~ Litter thickness shallow ~ shallow Bare ground ~ low high Gravel high ~ high Rock ~ ~ ~ Tree cover moderately low high moderately low Shrub cover low low high Forb cover high low high Grass cover high low ~ Total basal area ~ high low Stand density ~ ~ ~ R-5 Site class ~ ~ ~ Parent material ~ ~ ~ Parent material origin ~ ~ ~ Total soil depth ~ ~ ~ Surface horizon depth ~ ~ deep Surface horizon texture ~ ~ ~ Subsoil texture ~ ~ ~ Surface coarse fragments ~ gravelly, cobbly, stoney gravelly Subsoil coarse fragments low ~ ~ Rootability ~ ~ ~ Drainage ~ ~ ~ Available water holding capacity ~ low ~ Moisture stress low low ~ Soil acidity acid ~ ~ Soil temperature ~ low high Soil taxonomy ~ ochrepts ~ Soil particle size class ~ ~ ~
282 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Autecological Relationships of Selected Plants ––––––––––––––––––––––––––––––––––––– Moderate Site Indicators –––––––––––––––––––––––––––––––––––––– Feature ----------------------------------------------------------- Shrubs ----------------------------------------------------------- Artemesia tridentata Symphoricarpos acutus Symphoricarpos vaccinoides Physiognomy of typical community open, shrubby forest moderately dense forest open forest Distribution north, eastside north north Elevation high low middle, high Solar radiation index high ~ ~ Aspect se, sw ~ ~ Position ~ ~ ~ Slope ~ ~ ~ Microrelief ~ ~ ~ Litter thickness shallow ~ ~ Bare ground high ~ high Gravel high ~ high Rock ~ ~ ~ Tree cover moderately low ~ low Shrub cover high high high Forb cover high high high Grass cover high ~ high Total basal area low low low Stand density ~ ~ ~ R-5 Site class ~ ~ ~ Parent material volcanic, mixed ~ volcanic Parent material origin ~ ~ glacial till, outwash, colluvium, alluvium Total soil depth moderately shallow ~ ~ Surface horizon depth deep shallow shallow Surface horizon texture ~ medium ~ Subsoil texture moderately fine: loamy ~ moderately coarse to moderately fine Surface coarse fragments high, gravelly, cobbly ~ high, gravelly Subsoil coarse fragments ~ ~ ~ Rootability fractured ~ ~ Drainage ~ ~ ~ Available water holding capacity high ~ ~ Moisture stress ~ ~ ~ Soil acidity ~ acid ~ Soil temperature high ~ high Soil taxonomy inceptisols inceptisols ~ Soil particle size class ~ ~ ~
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 283 Autecological Relationships of Selected Plants ––––––––––––––––––––––––––––––––––––– Moderate Site Indicators –––––––––––––––––––––––––––––––––––––– Feature ---------------------------- Shrubs ------------------------------ -------- Forbs -------- Chrysothamnus viscidiflorus Wyethia mollis Hieracium albiflorum Physiognomy of typical community open forest open woodlands dense forest Distribution eastside north westside Elevation high middle middle, low Solar radiation index ~ high low Aspect ~ se, sw ~ Position ~ ~ lower slopes, toeslopes, benches Slope ~ ~ ~ Microrelief uniform , undulating ~ ~ Litter thickness shallow shallow moderately deep Bare ground high high low Gravel high high low Rock low ~ low Tree cover low low high Shrub cover high ~ low Forb cover high high ~ Grass cover high high low Total basal area low low high Stand density ~ ~ ~ R-5 Site class ~ ~ ~ Parent material volcanic ~ ~ Parent material origin ~ ~ ~ Total soil depth ~ ~ ~ Surface horizon depth ~ ~ ~ Surface horizon texture ~ ~ ~ Subsoil texture ~ ~ moderately coarse, medium: loamy Surface coarse fragments ~ ~ ~ Subsoil coarse fragments ~ ~ ~ Rootability ~ ~ ~ Drainage ~ ~ well Available water holding capacity ~ ~ high Moisture stress ~ ~ ~ Soil acidity ~ ~ ~ Soil temperature high high ~ Soil taxonomy entisols, mollisols inceptisols ~ Soil particle size class ~ ashy, medial skeletal ~
284 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Autecological Relationships of Selected Plants ––––––––––––––––––––––––––––––––––––– Moderate Site Indicators –––––––––––––––––––––––––––––––––––––– Feature ------------------------------------------------------------ Forbs ----------------------------------------------------------- Viola purpurea Pyrola picta Kelloggia galioides Physiognomy of typical community dense forest dense forest dense forest Distribution westside ~ north, westside Elevation middle,low middle, low middle, low Solar radiation index high low ~ Aspect se, sw ne,nw ~ Position ~ ~ ~ Slope moderate, shallow moderate ~ Microrelief ~ ~ ~ Litter thickness deep ~ deep Bare ground low low ~ Gravel low low ~ Rock ~ ~ ~ Tree cover high high high Shrub cover low low ~ Forb cover ~ ~ ~ Grass cover ~ low ~ Total basal area high high ~ Stand density ~ high ~ R-5 Site class ~ high ~ Parent material ~ ~ volcanic Parent material origin bedrock bedrock ~ Total soil depth ~ ~ ~ Surface horizon depth ~ ~ deep Surface horizon texture ~ ~ moderately coarse, medium Subsoil texture moderately coarse, medium moderately coarse, medium: loamy moderately coarse, medium: loamy Surface coarse fragments ~ ~ ~ Subsoil coarse fragments cobbly, stoney cobbly, stoney ~ Rootability ~ ~ ~ Drainage well ~ well Available water holding capacity high high high Moisture stress ~ ~ ~ Soil acidity acid acid acid Soil temperature low ~ ~ Soil taxonomy inceptisols inceptisols inceptisols Soil particle size class skeletal skeletal coarse loamy, fine loamy
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 285 Autecological Relationships of Selected Plants ––––––––––––––––––––––––––––––––––––– Moderate Site Indicators –––––––––––––––––––––––––––––––––––––– Feature --------------------------------------------------- Grass and Grass-like -------------------------------------------------- Poa Bolanderi Carex rossii Elymus glaucus Physiognomy of typical community dense forest open to dense forest open to dense forest Distribution north, westside north north Elevation middle, low high middle, low Solar radiation index ~ ~ high Aspect ~ ~ se, sw Position lower slopes, toeslopes, benches lower slopes, toeslopes, benches upper, middle, lower slopes Slope shallow shallow ~ Microrelief ~ broken, hummocky ~ Litter thickness ~ shallow ~ Bare ground low high high Gravel ~ high ~ Rock low ~ ~ Tree cover ~ ~ ~ Shrub cover high high high Forb cover high high high Grass cover high high high Total basal area ~ low low Stand density high low low R-5 Site class high low low Parent material volcanic ~ volcanic Parent material origin colluvium, alluvium ~ glacial till, outwash, colluvium Total soil depth deep moderate ~ Surface horizon depth deep ~ shallow Surface horizon texture medium, moderately fine: loamy medium, moderately fine medium, moderately fine, loamy Subsoil texture moderately coarse, medium medium, moderately fine medium, moderately fine, fine: loamy Surface coarse fragments ~ ~ ~ Subsoil coarse fragments low ~ high, gravelly, cobbly Rootability ~ hard ~ Drainage well ~ well Available water holding capacity high ~ high Moisture stress ~ ~ ~ Soil acidity ~ ~ ~ Soil temperature low ~ ~ Soil taxonomy inceptisols entisols inceptisols Soil particle size class ~ ~ medial skeletal
286 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Autecological Relationships of Selected Plants –– Moderate Site Indicators –– ––––––––––––––––––––– Moist Site Indicators –––––––––––––––––––– Feature ----- Grass and Grass-like ----- --------- Trees --------- ------ Shrubs ------ Bromus marginatus Populus tremuloides Ribes roezlii Physiognomy of typical community open forest dense forest dense forest Distribution north north, eastside north, westside Elevation ~ ~ middle, low Solar radiation index high ~ ~ Aspect se, sw ~ ~ Position ~ lower slopes, toeslopes, lower slopes, toeslopes, bottoms, benches benches Slope ~ shallow ~ Microrelief broken, hummocky ~ ~ Litter thickness ~ low deep Bare ground high ~ ~ Gravel high ~ ~ Rock ~ ~ ~ Tree cover low ~ high Shrub cover ~ ~ ~ Forb cover high high high Grass cover high high high Total basal area low ~ high Stand density low ~ high R-5 Site class low ~ high Parent material volcanic ~ ~ Parent material origin ~ glacial outwash, colluvium, alluvium ~ Total soil depth ~ ~ ~ Surface horizon depth shallow ~ deep Surface horizon texture medium, moderately fine, loamy medium, moderately fine, loamy medium, moderately fine, loamy Subsoil texture medium, moderately fine, fine, loamy moderately fine, fine, loamy medium, moderately fine, loamy Surface coarse fragments high, gravelly, cobbly ~ ~ Subsoil coarse fragments ~ ~ ~ Rootability ~ ~ ~ Drainage ~ well drained well drained Available water holding capacity ~ high high Moisture stress ~ low low Soil acidity ~ ~ ~ Soil temperature ~ ~ ~

Soil taxonomy alfisols, mollisols, alfisols, mollisols, inceptisolsSoil particle size class ~ ~ medial, loamy, ashy
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 287 Autecological Relationships of Selected Plants ––––––––––––––––––––––––––––––––––––––– Moist Site Indicators ––––––––––––––––––––––––––––––––––––––– Feature -------- Shrubs ---------- ------------------------------- Forbs --------------------------- Ribes montigenum Ligusticum Grayii Osmorhiza chilensis Physiognomy of typical community dense forest dense forest dense forest Distribution north, eastside north, westside ~ Elevation high ~ middle, low Solar radiation index ~ ~ ~ Aspect ~ ~ ~ Position lower slopes, toeslopes, benches lower slopes, toeslopes, benches lower slopes, toeslopes, benches Slope ~ shallow ~ Microrelief ~ ~ ~ Litter thickness ~ ~ ~ Bare ground ~ low low Gravel ~ low low Rock ~ low low Tree cover ~ high high Shrub cover low low low Forb cover high high high Grass cover high high high Total basal area ~ high high Stand density ~ ~ ~ R-5 Site class ~ ~ ~ Parent material ~ ~ ~ Parent material origin alluvium ~ glacial till, alluvium Total soil depth ~ ~ deep Surface horizon depth ~ medium: loamy ~ Surface horizon texture ~ medium, moderately fine: loamy medium, moderately fine, fine: loamy Subsoil texture ~ ~ medium, moderately fine, fine: loamy Surface coarse fragments ~ low low Subsoil coarse fragments ~ low low Rootability ~ ~ ~ Drainage ~ well drained well drained Available water holding capacity high high high Moisture stress low low low Soil acidity ~ ~ ~ Soil temperature ~ ~ ~ Soil taxonomy entisols inceptisols inceptisols Soil particle size class loamy, ashy loamy, loamy skeletal loamy
288 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Autecological Relationships of Selected Plants ––––––––––––––––––––––––––––––––––––––– Moist Site Indicators ––––––––––––––––––––––––––––––––––––––– Feature ------------------------------------------------------------ Forbs ----------------------------------------------------------- Pyrola secunda Thalictrum fendlerii Pteridium aquilinum Physiognomy of typical community dense forest dense forest dense forest Distribution ~ north, westside north, westside Elevation ~ ~ low Solar radiation index ~ ~ ~ Aspect ~ ~ sw, nw Position lower slopes, toeslopes, benches lower slopes, toeslopes, benches toeslopes, benches Slope shallow shallow ~ Microrelief ~ ~ ~ Litter thickness ~ ~ deep Bare ground ~ ~ low Gravel ~ low low Rock ~ low ~ Tree cover high high high Shrub cover low low high Forb cover high high ~ Grass cover high ~ ~ Total basal area high high high Stand density ~ ~ high R-5 Site class ~ ~ high Parent material ~ ~ granitic Parent material origin ~ ~ glacial till Total soil depth ~ ~ ~ Surface horizon depth ~ ~ ~ Surface horizon texture medium, moderately fine medium, moderately fine: loamy ~ Subsoil texture medium, moderately fine medium, moderately fine: loamy medium, loamy Surface coarse fragments low ~ ~ Subsoil coarse fragments low high ~ Rootability ~ ~ ~ Drainage well to poorly drained well drained well drained Available water holding capacity high high high Moisture stress low low low Soil acidity ~ ~ ~ Soil temperature ~ ~ ~ Soil taxonomy ~ inceptisols ~ Soil particle size class ~ loamy, medial skeletal loamy
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 289 Appendix E Environmental Summary by Plant Association Slope Bare Surface Surface Litter Plant Elevation (ft) Slope (pct) Aspect Position Ground (pct) Gravel (pct) Rock (pct) Depth (in) Association mean/range mean/range mode mode mean/range mean/range mean/range mean/range ASBO 7962 (7060-8800) 19 (8-31) NE, NW Upper 43 (21-80) 24 (6-42) 3 (0-15) 0.4 (0.1-1.0) POTR/MOOD 8046 (6920-9100) 18 (3-33) SE, SW, NW Middle, lower 4 (0-12) 7 (0-55) 3 (0-25) 1.0 (0.2-1.9) POTR/VECA1 7417 (6500-8600) 12 (2-31) All Lower 2 (0-12) 2 (0-15) 3 (0-10) 1.1 (0.2-2.9) JUOC/ARTR 8117 (7600-8720) 26 (8-42) SE, SW Upper 15 (3-30) 24 (5-50) 13 (0-62) 0.6 (0.2-1.1) JUOC 8133 (7560-8960) 32 (19-58) SE, SW Upper 6 (1-20) 13 (2-65) 27 (1-65) 0.9 (0.3-2.9) ABMA/WYMO 7899 (6940-8340) 22 (5-38) SE, SW Upper 10 (0-30) 23 (0-99) 4 (0-14) 0.6 (0.1-1.5) TSME//STEEP 8241 (7120-9360) 45 (30-60) NE, NW Upper 1 (0-3) 5 (1-20) 13 (0-49) 1.8 (0.2-8.0) TSME 8390 (7380-9160) 18 (2-29) NE, NW Upper, middle, lower 1 (0-32) 4 (0-32) 9 (0-43) 1.3 (0.4-3.0) ABMA-PIMO3/ARNE2 8364 (7200-9120) 28 (6-59) SE, SW Upper, middle 6 (0-25) 5 (0-40) 11 (0-65) 1.0 (0.2-3.5) ABMA-PIMO3/CASE3 8696 (8000-9200) 39 (25-65) NE, NW Upper, middle 3 (0-10) 6 (0-15) 18 (1-60) 1.3 (0.5-2.7) ABMA-PIMO3-PICO 8602 (7360-9640) 24 (3-65) NE, NW Upper, middle 2 (0-12) 10 (0-55) 9 0-50) 1.1 (0.6-2.2) ABMA-PIMO3 8465 (7140-9520) 25 (2-60) NE, NW Upper, middle 4 (0-36) 7 (0-75) 8 (0-63) 1.2 (0.2-3.8) ABCO-PILA-ABMA 6881 (5860-7880) 27 (3-60) All Middle, lower 0.8 (0-3) 0.9 (0-10) 3 (0-20) 1.9 (0.2-5.5) PIJE/QUVA 7320 (6300-8320) 27 (4-58) SE, SW Upper 3 (0-15) 4 (0-20) 13 (1-46) 1.2 (0.2-2.4) PIJE/ARPA9-CEVE3 8255 (6660-9520) 30 (4-64) SE, SW Upper 8 (1-49) 9 (0-43) 7 (0-30) 1.1 (0.3-2.2) PIJE/CECO2-ARTR 7967 (6820-9360) 20 (1-51) SE, SW Upper, middle, lower 12 (1-35) 14 (1-40) 3 (0-12) 0.8 (0.2-1.6) ABMA-ABCO-PIJE 7507 (6300-8800) 25 (0-57) SE, SW Upper 5 (0-40) 2 (0-10) 4 (0-20) 1.9 (0.2-6.0) PIJE-ABMA 8607 (7340-9120) 33 (12-47) SE, SW Upper 10 (0-43) 11 (1-35) 5 (0-24) 1.5 (0.2-2.2) PICO/ARTR 8510 (7560-9480) 22 (11-40) SE, SW Middle, lower 10 (2-25) 13 (2-30) 3 (0-20) 0.6 (0.2-1.0 PICO/LIGR1 7973 (6660-8920) 11 (3-32) NE, NW Lower 1 (0-4) 1 (0-6) 4 (0-25) 1.4 (0.4-2.4) PICO//WOODLANDS 8174 (7360-9080) 12 (5-30) All All 28 (3-80) 15 (1-55) 10 (0-53) 0.6 (0.1-1.0) PICO 8877 (8300-9320) 16 (4-30) All Lower, benches 3 (0-5) 11 (2-35) 2 (0-5) 1.0 (0.6-1.4) ABMA-PICO/HIAL 7831 (6540-9520) 13 (2-40) NE, NW, SW Lower, benches 2 (0-40) 4 (0-37) 3 (0-33) 1.6 (0.5-7.0) ABMA-ABCO 7319 (5780-8800) 26 (4-57) All Upper 1 (0-12) 2 (0-63) 5 (0-45) 2.0 (0.5-5.3) ABMA/ARNE2 7983 (7050-8800) 24 (2-47) All Upper, middle 3 (0-12) 4 (0-25) 10 (0-45) 1.0 (0.2-3.0) ABMA 8017 (6660-9240) 24 (2-60) NE, NW Upper, middle 3 (0-45) 4 (0-84) 5 (0-70) 1.6 (0.2-5.0)
290 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Appendix F Vegetation Summary by Plant Association Plant Association Vegetation Tree Shrub Forb Grass Total cover (pct) Cover (pct) Cover (pct) Cover (pct) Cover (pct) mean/range mean/range mean/range mean/range mean/range ASBO 64 (25-90) 4 (0-15) 6 (0-55) 44 (9-85) 14 (0-41) POTR/MOOD 94 (70-100) 71 (33-85) 13 (0-55) 50 (8-90) 43 (1-90) POTR/VECA1 94 (82-99) 78 (49-96) 12 (0-60) 36 (0-95) 18 (0_80) JUOC/ARTR 74 (35-99) 31 (4-75) 30 (1-92) 33 (8-70) 16 (2-60) JUOC 66 (24-99) 33 (3-79) 31 (3-65) 24 (1-80) 13 (1-80) ABMA/WYMO 79 (52-99) 25 (0-89) 5 (0-45) 54 (6-98) 19 (1-98) TSME//STEEP 68 (38-85) 65 (37-81) 1 (0-2) 2 (0-5) 1 (0-8) TSME 77 (23-97) 68 (22-88) 1 (0-15) 7 (0-35) 5 (0-45) ABMA-PIMO3/ARNE2 69 (30-100) 43 (11-79) 31 (2-82) 3 (0-25) 2 (0-9) ABMA-PIMO3/CASE3 70 (40-95) 51 (26-81) 29 (2-85) 9 (0-40) 1 (0-4) ABMA-PIMO3-PICO 73 (48-99) 63 (37-91) 1 (0-12) 9 (1-40) 5 (0-33) ABMA-PIMO3 75 (24-99) 66 (20-91) 2 (0-35) 7 (0-47) 2 (0-13) ABCO-PILA-ABMA 85 (62-98) 76 (37-93) 12 (0-66) 7 (0-41) 0.5 (0-2) PIJE/QUVA 83 (38-99) 36 (8-67) 55 (13-90) 10 (0-80) 1 (0-8) PIJE/ARPA9-CEVE3 74 (30-99) 40 (10-79) 41 (1-82) 7 (0-53) 4 (0-40) PIJE/CECO2-ARTR 76 (30-97) 36 (1-63) 28 (1-77) 19 (1-65) 15 (1-55) ABMA-ABCO-PIJE 76 (39-97) 65 (30-90) 10 (0-78) 13 (0-90) 2 (0-40) PIJE-ABMA 72 (18-98) 54 (17-83) 10 (0-50) 19 (1-83) 5 (0-30) PICO/LIGR1 94 (82-99) 76 (61-95) 4 (0-30) 40 (1-90) 17 (2-45) PICO/ARTR 83 (70-90) 44 (18-68) 26 (3-52) 37 (2-70) 25 (4-75) PICO//WOODLANDS 49 (18-72) 33 (16-48) 1 (0-2) 12 (1-30) 7 (0-30) PICO 67 (42-90) 59 (39-73) 0.4 (0-1) 3 (1-9) 10 (0-61) ABMA-PICO/HIAL 80 (47-99) 73 (43-95) 2 (0-40) 8 (0-95) 2 (0-25) ABMA-ABCO 85 (52-99) 78 (48-97) 3 (0-32) 13 (0-80) 2 (0-35) ABMA/ARNE2 84 (60-98) 51 (17-95) 52 (2-90) 3 (0-70) 2 (0-40) ABMA 82 (40-90) 77 (29-96) 2 (0-26) 5 (0-50) 1 (0-15)
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 291 Appendix G Soil Summary by Plant Association Plant Association Topsoil Subsoil Total soil Topsoil coarse Topsoil coarse Subsoil depth (in) depth (in) fragments (pct) texture fragments(pct) texture) AWC (“) mean/range mean/range mean/range mode mean/range mode mean/range ASBO 38 (30-40+) 17 (4-40+) 13 (7-20) sdl,l 18 (6-30) sdl,l 3.7 (2.1-6.5) POTR/MOOD 36 (26-40+) 12 (4-38) 22 (5-80) sdl,l,sdcl 38 (5-98) sdl,sdcl 3.4 (0.5-5.1) POTR/VECA1 37 (27-40+) 12 (2-37) 15 (1-55) l,sdl 27 (7-55) l,sdl 4.7 (1.7-6.3) JUOC/ARTR 26 (7-40+) 12 (4-28) 32 (14-60) sdl,l 47 (15-79) gsdl,l 2.3 (0.4-5.7) JUOC 30 (11-40+) 11 (3-16) 25 (10-46) sd,sdl 49 (13-75) sd,sdl 2.1 (0.5-3.8) ABMA/WYMO 34 (15-40+) 11 (3-22) 19 (3-46) sdl,l 40 (6-92) sdl,l 3.2 (0.8-5.9) TSME//STEEP 35 (22-40+) 6 (1-20) 32 (1-75) gsd,gsdl,gl 48 (1-88) sd,sdl,l 2.3 (0.5-5.4) TSME 32 (14-40+) 8 (0-60) 19 (2-65) sdl,l 32 (2-70) sd,sdl,l 2.8 (0.7-5.3) ABMA-PIMO3/ARNE2 31 (8-40+) 6 (2-11) 19 (5-38) sd,sdl 45 (10-86) sd,sdl 2.1 (0.3-4.4) ABMA-PIMO3/CASE3 33 (25-40+) 6 (2-8) 24 (2-60) sd 43 (7-75) sd 2.0 (0.9-2.8) ABMA-PIMO3-PICO 35 (19-40+) 6 (3-16) 28 (5-95) gsd 38 (1-87) gsd 2.7 (0.6-5.5) ABMA-PIMO3 34 (16-40+) 7 (3-15) 22 (2-55) sdl 49 (10-98) gsdl 2.5 (0.4-5.0) ABCO-PILA-ABMA 37 (26-40+) 10 (3-24) 23 (5-75) sdl,l 38 (5-80) sdl,l 3.4 (0.8-6.6) PIJE/QUVA 32 (13-40+) 9 (2-38) 25 (3-65) gsd,sdl 46 (5-85) stsd,sdl 2.4 (0.6-5.4) PIJE/ARPA9-CEVE3 32 (5-40+) 8 (2-23) 22 (2-55) sd,sdl 43 (3-92) sd,sdl 2.2 (0.2-5.2) PIJE/CECO2-ARTR 35 (17-40+) 10 (3-22) 20 (2-80) sd,sdl 37 (4-90) sd,sdl,l 2.8 (0.1-5.3) ABMA-ABCO-PIJE 39 (28-40+) 8 (3-20) 13 (1-52) sdl 26 (5-80) sdl 3.8 (1.2-6.4) PIJE-ABMA 38 (17-40+) 9 (4-16) 36 (6-80) gsd 36 (5-85) gsd 2.2 (0.5-3.9) PICO/LIGR1 35 (22-40+) 9 (3-31) 14 (1-42) l 32 (1-86) l 3.8 (1.7-5.7) PICO/ARTR 37 (26-40+) 12 (8-20) 30 (10-75) sdl,l 38 (15-55) sdl,l 3.3 (1.9-4.6) PICO//WOODLANDS 33 (13-40+) 7 (2-15) 15 (2-45) sd,sdl 18 (2-40) sd,sdl 2.7 (1.3-4.6) PICO 39 (31-40+) 11 (4-23) 33 (8-95) sd,sdl 38 (8-85) sd,sdl 3.4 (1.2-5.8) ABMA-PICO/HIAL 37 (24-40+) 9 (2-28) 20 (1-95) sdl,l 30 (10-87) sdl,l 3.7 (1.0-6.0) ABMA-ABCO 39 (19-40+) 10 (2-36) 15 (1-65) sdl,l 26 (5-75) sdl,l 4.1 (0.6-6.9) ABMA/ARNE2 30 (11-40+) 8 (2-17) 25 (2-75) sdl 49 (6-80) csdl 2.3 (0.4-4.9) ABMA 38 (18-40+) 8 (2-25) 20 (0-98) sdl 38 (0-99) sdl 3.3 (0.7-6.5)
292 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. Appendix H Productivity Summary by Plant Association Region 5 Forest Survey Stand Density Cubic Foot Total Basal Site Index Site Class Index Volume Area Plant Association mean/range mean/range mean/range mean/range mean/range ASBO 3 (1-4) 4 (2-5) 76 (0-167) 2.1 (0-4.8) 48 (0-140) POTR/VECA1 1 (0-3) 2 (1-4) 519 (119-1124) 11.5 (5.6-28.8) 229 (20-547) POTR/MOOD 3 (1-5) 4 (2-6) 401 (163-711) 6.4 (1.9-10.6) 117 (7-240) JUOC/ARTR 4 (3-5) 5 (4-6) 242 (117-438) 4.5 (1.6-7.7) 159 (48-267) JUOC 4 (2-5) 5 (3-6) 225 (44-464) 4.2 (1.7-8.8) 129 (40-320) ABMA/WYMO 3 (1-5) 4 (2-6) 171 (50-401) 5.4 (1-16.6) 122 (32-344) TSME//STEEP 3 (3-5) 4 (3-6) 523 (95-816) 10.0 (4.2-16.5) 353 (213-507) TSME 3 (1-5) 4 (2-6) 541 (141-1239) 10.2 (1.3-21.0) 364 (116-680) ABMA-PIMO3/ARNE2 4 (2-5) 5 (3-6) 274 (124-482) 6.1 (2.5-12.9) 196 (5-400) ABMA-PIMO3/CASE3 3 (1-5) 4 (2-6) 287 (196-417) 7.3 (3.5-10.6) 229 (120-320) ABMA-PIMO3-PICO 4 (2-5) 5 (3-4) 425 (114-659) 7.0 (2.0-15.2) 287 (88-453) ABMA-PIMO3 3 (1-5) 4 (2-6) 411 (135-723) 10.3 (2.8-25.7) 316 (80-600) ABCO-PILA-ABMA 1 (0-3) 2 (1-4) 458 (99-824) 13.5 (1.1-24.3) 347 (88-587) PIJE/QUVA 3 (2-5) 4 (3-6) 224 (50-592) 5.2 (1.2-14.2) 155 (40-320) PIJE/ARPA9-CEVE3 3 (2-4) 4 (3-5) 177 (50-324) 4.3 (1.6-12.9) 122 (27-307) PIJE/CECO2-ARTR 3 (2-4) 4 (3-5) 252 (106-491) 5.5 (2.5-8.7) 157 (56-280) ABMA-ABCO-PIJE 2 (0-4) 3 (1-5) 386 (101-870) 12.0 (4.7-25.5) 287 (56-560) PIJE-ABMA 3 (2-3) 4 (3-4) 324 (92-647) 8.0 (3.4-12.8) 234 (88-413) PICO/LIGR1 3 (1-5) 4 (2-6) 489 (223-951) 8.6 (3.0-21.2) 333 (220-600) PICO/ARTR 4 (2-5) 5 (3-6) 225 (99-429) 4.3 (1.5-9.8) 154 (56-240) PICO//WOODLANDS 4 (3-5) 5 (4-6) 212 (53-390) 3.8 (1.4-9.0) 139 (32-248) PICO 4 (4-5) 5 (5-6) 448 (341-606) 4.6 (2.8-5.7) 275 (208-360) ABMA-PICO/HIAL 2 (0-5) 3 (1-6) 531 (272-953) 11.6 (4.4-23.4) 354 (187-560) ABMA-ABCO 1 (0-3) 2 (1-4) 520 (200-948) 15.1 (5.5-29.7) 372 (150-627) ABMA/ARNE2 3 (1-5) 4 (2-6) 290 (118-750) 7.1 (2.9-15.7) 221 (72-493) ABMA 2 (0-4) 3 (1-5) 517 (136-1104) 15.0 (2.8-30.0) 402 (93-693)
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 293

Appendix I

Common Plants of the Upper Montane

Species Code Scientific Name Common Name Constancy

Tree Overstory

ABCO Abies concolor White fir 25

ABMA Abies magnifica Red fir 81

JUOC Juniperus occidentalis Western juniper 4

LIDE3 Calocedrus decurrens Incense cedar <1

PIAL Pinus albicaulis Whitebark pine <1

PICO Pinus contorta Lodgepole pine 24

PIJE Pinus jeffreyii Jeffrey pine 21

PILA Pinus lambertiana Sugar pine 2

PIMO3 Pinus monticola Western white pine 21

POTR Populus tremuloides Quaking aspen 3

QUKE Quercus kelloggii Black oak 1

QUWI Quercus wislizenii Interior live oak 1

TSME Tsuga mertensiana Mountain hemlock 6

Tree Understory

ABCO Abies concolor White fir 29

ABMA Abies magnifica Red fir 82

JUOC Juniperus occidentalis Western juniper 5

LIDE3 Calocedrus decurrens Incense cedar 2

PIAL Pinus albicaulis Whitebark pine 2

PICO Pinus contorta Lodgepole pine 23

PIJE Pinus jeffreyii Jeffrey pine 12

PILA Pinus lambertiana Sugar pine 2

PIMO3 Pinus monticola Western white pine 21

POTR Populus tremuloides Quaking aspen 5

QUKE Quercus kelloggii Black oak 1

TSME Tsuga mertensiana Mountain hemlock 8

Shrubs

ACGLT Acer glabrum torreyi Mountain maple <1

ALTE Alnus tenuifolia Mountain alder <1

AMPA2 Amelanchier pallida Pallid service berry 1

AMPU3 Amelanchier pumila Service berry <1

ARNE2 Arctostaphylos nevadensis Pinemat manzanita 15

ARPA9 Arctostaphylos patula Greenleaf manzanita 6

ARAR Artemisia arbuscula Dwarf sagebrush <1

ARCA8 Artemisia cana Hoary sagebrush <1

ARRO3 Artemisia rothrockii Timberline sagebrush <1

ARTR Artemisia tridentata Sagebrush 7

BESO Berberis sonnei Truckee barberry <1

CAME3 Cassiope mertensiana White heather <1

CASE3 Castanopsis sempervirens Sierra chinquapin 15
294 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Species Code Scientific Name Common Name Constancy

Shrubs, continued

CECO2 Ceanothus cordulatus Mountain whitethorn 10

CEDI3 Ceanothus diversifolius Trailing ceanothus <1

CEFR Ceanothus fresnensis Creeping ceanothus <1

CEPI Ceanothus pinetorum Kern ceanothus 1

CEVE3 Ceanothus velutinus Snowbrush 3

CELE3 Cercocarpus ledifolius Curlleaf mountain mahogany <1

CHNA2 Chrysothamnus nauseosus Common rabbit brush <1

CHPA9 Chrysothamnus parryi Parry’s rabbit brush <1

CHR9 Chrysothamnus sp. (woody shrub) Rabbit brush <1

CHVI4 Chrysothamnus viscidiflorus Sticky-leaved rabbit brush 1

CONU2 Cornus nuttallii Mountain dogwood <1

COST3 Cornus stolonifera American dogwood <1

COCOC Corylus cornuta californica California hazelnut <1

ERPR5 Eriogonum prattenianum Eriogonum <1

HABL Haplopappus bloomeri Bloomer’s goldenbush <1

HOBO2 Holodiscus boursieri Oceanspray 1

HOMI2 Holodiscus microphyllus Rock sprirea <1

KAPOM Kalmia polifolia microphylla Alpine laurel <1

LEDA Leucothoe davisiae Sierra laurel <1

LOCO3 Lonicera conjugialis Double honeysuckle 2

LOIN4 Lonicera involucrata Black twinberry <1

PERO Penstemon rothrockii Rothrock’s penstemon <1

PHBR4 Phyllodoce breweri Red mountain heather <1

PREM Prunus emarginata Bitter cherry 5

PUTR Purshia tridentata Bitter brush 2

QUVA Quercus vaccinifolia Huckleberry oak 10

RHOC Rhododendron occidentale Western azalea <1

RICE Ribes cereum Squaw currant 7

RIDI Ribes divaricatum Straggly gooseberry <1

RIMO Ribes montigenum Alpine prickly currant 5

RINE Ribes nevadense Sierra Nevada currant <1

RIRO Ribes roezlii Sierra gooseberry 12

RIB Ribes sp. (woody shrub) Currant 1

RIVE Ribes velutinum Plateau gooseberry <1

RIVE3 Ribes viscosissimum Sticky currant 7

ROPI1 Rosa pinetorum Pinerose <1

RUPA2 Rubus parviflorus Thimble berry <1

SAEA Salix eastwoodiae Eastwood’s willow <1

SALU Salix lutea Yellow willow <1

SAL11 Salix sp. (woody shrub) Willow <1

SACA4 Sambucus caerulea Blue elderberry <1

SAME5 Sambucus melanocarpa Black elderberry <1

SAMI4 Sambucus microbotrys Mountain red elderberry 1

SOCA3 Sorbus californica Western mountain ash <1

SOSC Sorbus scopulina Mountain ash <1

SPDES Spiraea densiflora splendens Mountain spirea 1

SYAC Symphoricarpos acutus Creeping snowberry 13
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 295

Species Code Scientific Name Common Name Constancy

Shrubs, continued

SYPA Symphoricarpos parshii Parish’s snowberry 7

SYM3 Symphoricarpos sp. (woody shrub) Snowberry <1

SYVA Symphoricarpos vaccinioides Mountain snowberry 5

TECA Tetradymia canescens Gray horsebrush 1

VANI Vaccinium nivictum Dwarf huckleberry <1

Forbs

ACLA2 Achillea lanulosa Common yarrow 3

ACCO2 Aconitum columbianum Columbia monkshood <1

ADBI Adenocaulon bicolor Trail plant 1

AGUR Agastache urticifolia Nettle-leaved horsemint <1

AGUT Agave utahensis Utah agoseris <1

AGEL2 Agoseris elata Tall agoseris <1

AGGLL Agoseris glauca laciniata Short-beaked agoseris <1

AGRE2 Agoseris retrorsa Spear-leaved agoseris <1

AGO3 Agoseris sp. (herb-longevity unk) Agoseris <1

ALCA2 Allium campanulatum Sierra onion 6

ALFIA Allium fimbriatum abramsii Fringed onion <1

ALOB Allium obtusum Red sierra onion 4

ALPA3 Allium parvum Dwarf onion <1

ALL2 Allium sp. herbaceous perennial Onion 2

ALTR2 Allium tribracteatum Three-bracted onion <1

ALVA Allium validum Swamp onion <1

ALDI2 Allophyllum divaricatum Pink false gilia <1

ALIN2 Allophyllum integrifolium Allophyllum <1

ALVI1 Allophyllum violaceum Allophyllum <1

ALVI2 Allotropa virgata Sugar stick <1

ANMA1 Anaphalis margaritacea Pearly everlasting <1

ANBR2 Angelica breweri Brewer’s angelica 3

ANLI Angelica lineariloba Sierra angelica 1

ANCO1 Antennaria corymbosa Meadow everlasting <1

ANRO Antennaria rosea Rosy everlasting 2

APMEF Apocynum medium floribundum Western dogbane 7

APPU Apocynum pumilum Mountain dogbane 1

AQFO Aquilegia formosa Northwest crimson columbine <1

ARBR Arabis breweri Brewer’s rock cress <1

ARDI5 Arabis divaricarpa Bent-pod rock cress 2

ARDR2 Arabis drummondii Drummond’s rock cress <1

ARHIG Arabis hirsuta glabrata Hairy rock cress <1

ARHOR Arabis holboellii retrofracta Holboell’s rock cress 4

ARHOP Arabis holboellii pinetorum Holboell’s rock cress 1

ARIN1 Arabis inyoensis Inyo rock cress <1

ARLE Arabis lemmonii Lemmon’s rock cress <1

ARLY Arabis lyallii Lyal’s rock cress <1

ARMI2 Arabis microphylla Small-leaved rock cress <1

ARPL Arabis platysperma Broad-seeded rock cress 35

ARPLH Arabis platysperma howellii Howell’s rock cress <1
296 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Species Code Scientific Name Common Name Constancy

Forbs, continued

ARPU4 Arabis pulchra Beautiful rock cress <1

ARRE1 Arabis rectissima Bristly-leaved rock cress 1

ARRE2 Arabis repanda Repand rock cress 8

ARA2 Arabis sp. (herb-ann or bien) Rock cress 1

ARA3 Arabis sp. (herb-peren) Rock cress <1

ARSPA Arabis sparsiflora arcuata Elegant rock cress <1

ARSU3 Arabis suffrutescens Woody rock cress <1

ARCOS Arenaria congesta subcongesta Capitate sandwort <1

ARNUG Arenaria nuttallii gracilis Nuttall’s sandwort <1

ARKIG Arenaria kingii glabrescens King’s sandwort 1

ARMO2 Arnica mollis Cordilleran arnica <1

ARPAS Arnica parryi sonnei Nodding arnica <1

ARLUI Artemisia ludoviciana incompta Western mugwort <1

ASC1 Asclepias sp. (herb-peren) Milkweed <1

ASAD Aster adscendens Long-leaved aster <1

ASCAB Aster campestris bloomerii Western meadow aster <1

ASEA Aster eatonii Eaton’s aster <1

ASFO Aster foliaceus Leafy aster <1

ASIN1 Aster integrifolius Entire-leaved aster <1

ASOCI Aster occidentalis intermedius Western mountain aster <1

ASOCY Aster occidentalis yosemitanus Western mountain aster <1

AST2 Aster sp. (herb-peren) Aster 1

ASBO Astragalus bolanderi Bolander’s locoweed 1

ATALA Athyrium alpestra americanum Alpine lady fern <1

BASA1 Balsamorhiza sagittata Arrow-leaved balsam root <1

BEER Berula erecta Cut-leaved water parsnip <1

BREL Brodiaea elegans Harvest brodiaea <1

BRLU2 Brodiaea lutea Yellow brodiaea 6

CAER Calliandra eriophylla Hairy-leaved calliandra <1

CAIN5 Calochortus invenustus Plain mariposa lily <1

CALE6 Calochortus leichtlinii Leichtlin’s mariposa lily 1

CAL5 Calochortus sp. (herb-peren) Mariposa lily 1

CAHO2 Caltha howellii White marsh marigold <1

CAUM2 Calyptridium umbellatum Pussy paws 10

CAPR6 Campanula prenanthoides California harebell <1

CABR8 Cardamine breweri Brewer’s bitter cress <1

CAAP Castelleja applegatei Wavy-leaved indian paint brush 7

CADI3 Castelleja disticha Eastwood’s indian paint brush <1

CALI3 Castelleja linariaefolia Linear-leaved indian paint brush <1

CAMI4 Castelleja miniata Great red indian paint brush <1

CAPR7 Castelleja pruinosa Pruinose indian paint brush <1

CHDO1 Chaenactis douglasii Hoary chaenactis 3

CHNE2 Chaenactis nevadensis Northern sierra chaenactis <1

CHAL3 Chenopodium album Lambs quarters <1

CHAT Chenopodium atrovirens Pigweed <1

CHDE1 Chenopodium desiccatum Narrow-leaved pigweed <1

CHME2 Chimaphila menziesii Little prince’s pine 3
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 297

Species Code Scientific Name Common Name Constancy

Forbs, continued

CHUMO Chimaphila umbellata occidentalis Western prince’s pine 3

CHUBR3 Chrysopsis breweri Brewer’s golden aster 25

CIAN1 Cirsium andersonii Anderson’s thistle 5

CIDR Cirsium drummondii Dwarf thistle <1

CLRH Clarkia rhomboidea Rhomboid clarkia <1

CLLAS Claytonia lanceolata sessilifolia Western spring beauty <1

COGR1 Collinsia grandiflora Large-flowered blue eyed mary <1

COPA2 Collinsia parviflora Small-flowered blue eyed mary 1

COTO1 Collinsia torreyi Torrey’s blue eyed mary 4

COTOW Collinsia torreyi wrightii Wright’s blue eyed mary 16

COGR3 Collomia grandiflora Large-flowerd collomia <1

COLI2 Collomia linearis Narrow-leaved collomia 3

COTI2 Collomia tinctoria Yellow-stanining collomia <1

COMA3 Convolvulus malacophyllus Sierra morning glory <1

COMA4 Corallorhiza maculata Spotted coral root 21

COST1 Corallorhiza striata Striped coral root <1

CORAS Cordylanthus ramosus setosus Much branched bird’s beak <1

CRAC2 Crepis acuminata Long-leaved hawksbeard <1

CRBA1 Crepis bakeri Baker’s hawksbeard <1

CRIN1 Crepis intermedia Intermediate hawksbeard <1

CRMOS Crepis modocensis subacaulis Low hawksbeard <1

CROC Crepis occidentalis Western hawksbeard <1

CRE2 Crepis sp. (herb-peren) Hawksbeard <1

CRY2 Cryptantha sp. (herb-ann or bien) Cryptantha 6

CRY3 Cryptantha sp. (herb-peren) Cryptantha <1

CRTO Cryptantha torreyana Torrey’s cryptantha <1

CRAC1 Cryptogramma acrostichoides American parsley fern <1

CYOC Cynoglossum occidentale Western hounds tongue 1

DENU2 Delphinium nuttallianum Nuttalls larkspur 1

DEPR Delphinium pratense Meadow larkspur <1

DEL1 Delphinium sp. (longevity unk) Larkspur 2

DEL2 Delphinium sp. (herb-peren) Larkspur <1

DEPA3 Dentaria pachystigma Stout-beaked toothwort <1

DECA5 Descurainia californica Sierra tansy mustard <1

DERII Descuraninia richardsonnii incisa Mountain tansy mustard 2

DIUM Dicentra uniflora Steer’s head <1

DIHO2 Disporum hookeri Hooker’s fairy bell 1

DOJE Dodecatheon jeffreyi Jeffrey’s shooting star <1

DRCR1 Draba crassifolia Draba <1

DRSTN Draba stenoloba Alaska Whitlow grass <1

DRAR Dryopteris arguta Coastal wood fern <1

EPAN2 Epilobium angustifolium Fireweed 2

EPBR Epilobium brevistylum Slender willow herb <1

EPEX Epilobium exaltatum Elevated willow herb <1

EPGL1 Epilobium glaberrimum Glaucous willow herb <1

EPLA1 Epilobium lactiflorum White-flowered willow herb <1

EPPA Epilobium paniculatum Panicled willow herb <1
298 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Species Code Scientific Name Common Name Constancy

Forbs, continued

EPI2 Epilobium sp. (herb-peren) Willow herb <1

EQFU Equisetum funstoni California horsetail <1

EQU Equisetum sp. (herb-peren) Horsetail <1

ERBR2 Erigeron breweri Brewer’s daisy 10

ERCO5 Erigeron coulteri Coulter’s daisy <1

ERIN2 Erigeron inornatus California rayless daisy <1

ERPEA Erigeron peregrinus angustifolius Wandering daisy 5

ERI6 Erigeron sp. (herb-peren) Daisy 2

ERBR3 Eriogonum brachyanthum Short-flowered eriogonum <1

ERIN6 Erigonum incanum Hoary erigonum 2

ERLAN Eriogonum latifolium nudum Coast eriogonum 2

ERMA3 Eriogonum marifolium Marum-leaved eriogonum 3

ERNU3 Eriogonum nudum Naked-stemmed eriogonum <1

ERNUN Eriogonum nudum nudum Naked-stemmed eriogonum 1

ERNUD Eriogonum nudum deductum Naked-stemmed eriogonum 13

ERPO2 Eriogonum polypodum Eriogonum <1

ERI11 Eriogonum sp. (herb-longevity unk) Eriogonum <1

ERSP2 Eriogonum spergulinum Spurry eriogonum 5

ERUM Eriogonum umbellatum Sulphur-flowered eriogonum 1

ERUMP Eriogonum umbellatum polyanthum Sulphur-flowered eriogonum 2

ERWRS Eriogonum wrightii subscaposum Wright’s eriogonum <1

ERLA6 Eriophyllum lanatum Common wooly sunflower <1

ERLAM Eriophyllum lanatum monoense Common wooly sunflower 1

ERCA3 Erysimum capitatum Douglas’ wallflower <1

ERPE3 Erysimum perenne Sierra wallflower 17

EUOC1 Eupatorium occidentale Western eupatorium <1

FRCA1 Fragaria californica California strawberry <1

FRPL1 Fragaria platypetala Broad-petaled strawberry 1

FRVIP Fragaria virginiana Mountain strawberry <1

FRSP Frasera speciosa Deer tongue 1

FRTU Frasera tubulosa Kern swertia <1

GAAS Galium asperrimum Tall rough bedstraw 1

GABI Galium bifolium Low mountain bedstraw <1

GABO1 Galium bolanderi Bolander’s bedstraw <1

GAL2 Galium sp. (herb-ann or bien) Bedstraw <1

GAL5 Galium sp. (semiwoody herb) Bedstraw <1

GASP1 Galium sparsiflorum Sequoia bedstraw <1

GATRS Galium trifidum subbiflorum Trifid bedstraw <1

GADE Gayophytum dicepiens Gravel gayophytum <1

GADI2 Gayophytum diffusum Diffuse gayophytum 2

GAER Gayophytum eriospermum Covilles’s gayophytum 20

GAHU1 Gayophytum humile Low gayophytum <1

GANU1 Gayophytum nuttallii Nuttall’s gayophytum 2

GARA1 Gayophytum racemosum Black-foot gayophytum 1

GARA2 Gayophytum ramosissimum Much-branched gayophytum 1

GAY Gayophytum sp. (herb-ann or bien) Gayophytum <1

GEHO Gentiana holopetala Sierra gentian <1
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 299

Species Code Scientific Name Common Name Constancy

Forbs, continued

GECA3 Geranium californicum California geranium <1

GERI Geranium richardsonii Richardson’s geranium <1

GEMA Geum macrophyllum Large-leaved avens <1

GICA3 Gilia capillaris Smooth-leaved gilia <1

GILE1 Gilia leptales Bridge’s gilia <1

GOOB Goodyera oblongifolia Rattlesnake plantain 1

HADIL Habenaria dilatata leucostachys Boreal bog orchid <1

HAEL Habenaria elegans Elegant piperia <1

HAUN1 Habenaria unalascensis Alaska piperia <1

HACA1 Hackelia californica California stickseed 5

HAFL Hackelia floribunda Many-flowered stickseed <1

HAJE Hackelia jessicae Jessica’s stickseed 3

HALO Hackelia longituba Velvety stickseed <1

HAMU Hackelia mundula Pink stickseed 1

HANE Hackelia nervosa Sierra stickseed <1

HAC1 Hackelia sp. (herb-peren) Stickseed <1

HAVE Hackelia velutina Velvety stickseed 6

HAWH Haplopappus whitneyi Whitney’s haplopappus <1

HEHO Helenium hoopesii Tall mountain helenium <1

HELA2 Heracleum lanatum Cow parsnip <1

HERUA Heuchera rubescens alpicola Pink heuchera <1

HIAL Hieracium albiflorum White-flowered hawkweed 22

HIGR1 Hieracium gracile Alpine hawkweed <1

HIHO Hieracium horridum Shaggy hawkweed 1

HUBR Hulsea brevifolia Short-leaved hulsea <1

HYOC Hydrophyllum occidentale California waterleaf 1

IPAG Ipomopsis aggregata Scarlet gilia 2

IVSA Ivesia santolinoides Mouse-tail ivesia <1

KEGA Kelloggia galioides Kellogg’s bedstraw 18

LALA2 Lathyrus lanszwertii Nevada pea <1

LAGL4 Layia glandulosa White layia <1

LEVIP Lepidium virginicum pubescens Wild peppergrass <1

LELE4 Lewisia leana Lee’s lewisia <1

LETR2 Lewisia triphylla Three-leaved lewisia <1

LIGR1 Ligusticum grayi Gray’s lovage 6

LIKE1 Lilium kelleyanum Kelley’s lily <1

LIPA1 Lilium paradalinum Leopard lily <1

LIPA3 Lilium parvum Small tiger lily <1

LIL2 Lilium sp. (herb-peren) Lily <1

LICI Linanthus ciliatus Bristly-leaved linanthus 4

LIHA Linanthus harknessii Harkness’ linanthus <1

LIMO2 Linanthus montanus Mustang clover <1

LINU2 Linanthus nuttallii Nuttall’s linanthus 1

LIN2 Linanthus sp. (herb-ann or bien) Linanthus 1

LIPEL Linum perenne lewisii Western blue flax <1

LIBU Lithophragma bulbiferum Rock star <1

LIHE Lithophragma heterophyllum Hill star <1
300 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Species Code Scientific Name Common Name Constancy

Forbs, continued

LIT2 Lithospermum sp. (herb-ann or bien) Stoneseed <1

LODIM Lomatium dissectum multifidum Fern-leaved lomatium <1

LOMA3 Lomatium macrocarpum Large-fruited lomatium <1

LOPL Lomatium plummerae Plummer’s lomatium <1

LORI1 Lomatium rigidum Inyo lomatium <1

LOM2 Lomatium sp. (semiwoody herb) Lomatium <1

LOTO2 Loamtium toreyi Torrey’s lomatium <1

LOCU Lotus cupreus Copper-flowered bird’s-foot trefoil <1

LONE3 Lotus nevadensis Sierra nevada trefoil <1

LOOB Lotus oblingifolius Narrow-leaved trefoil <1

LUADU Lupinus adsurgens undulatus Drew’s silky lupine 6

LUAL1 Lupinus albicaulis Sickle-keeled lupine 3

LUAN2 Lupinus andersonii Anderson’s lupine 7

LUAL3 Lupinus arbifrons Silver lupine <1

LUAR4 Lupinus arbustus Douglas’ spurred lupine <1

LUBR2 Lupinus breweri Brewer’s lupine <1

LUCA2 Lupinus caudatus Kellogg’s spurred lupine <1

LUDU Lupinus duranii Lupine <1

LUEX Lupinus excubitus Interior bush lupine <1

LUFU Lupinus fulcratus California green-stipuled lupine 2

LUGR1 Lupinus gracilentus Greene’s slender lupine <1

LULAC Lupinus latifolius columbianus Broad-leaved lupine 4

LULO1 Lupinus lobbii Dwarf lupine <1

LULY Lupinus lyallii Lyall’s lupine <1

LUME Lupinus meionanthus Gray’s many-flowered lupine <1

LUBO Lupinus obtusilobus Ornate lupine <1

LUPOS Lupinus polyphyllus superbus Large-leaved lupine <1

LUSE1 Lupinus sellulus Torrey’s lupine <1

LUP3 Lupinus sp. (longevity unk) Lupine <1

LUP2 Lupinus sp. (herb-peren) Lupine 3

LUST Lupinus stiversii Stiver’s annual lupine <1

LUSU5 Lupinus sublanatus Lupine <1

MACA1 Machaeranthera canescens Hoary aster <1

MASHM Machaeranthera shastensis montana Shasta aster <1

MAEX1 Madia exigua Small tarweed <1

MAGL1 Madia glomerata Mountain tarweed <1

MAMI1 Madia minima Hemizonella <1

MEAR3 Mentha arvensis Field mint <1

MEAL2 Mentzelia albicaulis White-stemmed stick leaf <1

MECIS Mertensia ciliata stomatechoides Ciliate lungwort <1

MINU1 Microseris nutans Nodding scorzonella <1

MIGR1 Microsteris gracilis Slender phlox <1

MIAR1 Mimulus arenarius Sand-loving monkey flower <1

MICO1 Mimulus coccineus Sierra monkey flower <1

MIFL1 Mimulus floribundus Floriferous monkey flower 1

MIGU Mimulus guttatus Common large monkey flower <1

MILE1 Mimulus leptaleus Least-flowered monkey flower <1
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 301

Species Code Scientific Name Common Name Constancy

Forbs, continued

MIME Mimulus mephiticus Skunky monkey flower <1

MINA2 Mimulus nasutus Snouted monkey flower <1

MIPR Mimulus primuloides Primrose monkey flower <1

MIM1 Mimulus sp. (herb-ann or bien) Monkey flower <1

MIM2 Mimulus sp. (herb-peren) Monkey flower <1

MIWH2 Mimulus whitneyi Varicolored monkey flower <1

MIBR6 Mitella breveri Brewer’s mitrewort 1

MOOD Monardella odoratissima Mountain pennyroyal 22

MOODP Monardella odoratissima pallida Mountain pennyroyal 3

MOPE2 Montia perfoliata Miner’s lettuce <1

MOSIH Montia sibirica heterophylla Candy flower <1

MYMI2 Myosurus minimus Common mouse tail <1

NEM3 Nemophila sp. (herb-ann or bien) Nemophila <1

NESP Nemophila spatulata Sierra nemophilla <1

NOAL Nothocalais alpestris Alpine lake agoseris <1

ONDE Onychium densum Indian’s dream <1

ORCAC Orobanche californica corymbosa California broomrape <1

ORUNP Orobanche uniflora purpurea Naked broomrape <1

ORTH Orochaenactis thysanocarpha Orochaenactis <1

ORCOC Orthocarpus copelandii cryptanthus Copeland’s orthocarpus 1

ORT Orthocarpus sp. (herb-ann or bien) Orthocarpus <1

OSCH Osmorhiza chilensis Mountain sweet-cicely 12

OSOC Osmorhiza occidentalis Western sweet-cicely 1

OSM Osmorhiza sp. (herb-peren) Sweet-cicely <1

PABR Paeonia brownii Western peony 1

PESE3 Pedicularis semibarbata Pine-woods lousewort 45

PEBR3 Pellaea bridgeii Bridge’s cliff brake <1

PEAZ Penstemon asureus Azure penstemon <1

PEBR4 Penstemon bridgesii Bridge’s penstemon 1

PECA5 Penstemon caesius Cushion penstemon 3

PEGR3 Penstemon gracilentus Slender penstemon <1

PEHE2 Penstemon heterodoxus Sierran penstemon <1

PELA2 Penstemon laetus Gay penstemon 2

PENE3 Penstemon newberryi Mountain pride 3

PEOR1 Penstemon oreocharis Meadow penstemon <1

PEPA8 Penstemon parvulus Small azure penstemon <1

PERY Penstemon rydbergii Rydberg’s meadow penstemon <1

PEN2 Penstemon sp. (herb-peren) Penstemon <1

PEN3 Penstemon sp. (semiwoody-herb) Penstemon <1

PESP1 Penstemon speciosus Showy penstemon <1

PEBO Perideridia bolanderi Bolander’s yampah <1

PEPA5 Perideridia parishii Parish’s yampah 2

PHFR2 Phacelia frigida Timberline phacelia <1

PHHA Phacelia hastata Silverleaf phacelia <1

PHHE1 Phacelia heterophylla Virgate phacelia 5

PHHY Phacelia hydrophylloide Waterleaf phacelia 24

PHIM Phacelia imbricata Imbricate phacelia 1
302 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Species Code Scientific Name Common Name Constancy

Forbs, continued

PHMU2 Phacelia mutablis Changeable phacelia 5

PHPU1 Phacelia purpusii Purpus phacelia <1

PHQU Phacelia quickii Persistent-flowered phacelia <1

PHRA1 Phacelia racemosa Racemose phacelia <1

PHRA2 Phacelia ramosissima Branching phacelia 5

PHA4 Phacelia sp. (herb-ann or bien) Phacelia <1

PHCO4 Phlox covillei Coville’s phlox <1

PHDI4 Phlox diffusa Spreading phlox 5

PHSPO Phlox speciosa occidentalis Showy phlox <1

PHBR4 Phyllodoce breweri Brewer’s mountain heather <1

PLFI Pleuricospora fimbriolata Fringed pine-sap 1

POCAA Polemonium caeruleum amygdalinum Western polemonium <1

POCA4 Polemonium californica Low polemonium 2

POBI3 Polygonum bistortoides Western bistort <1

PODA Polygonum davisiae Davis’ knotweed <1

PODO3 Polygonum douglasii Douglas’ knotweed 3

POKE2 Polygonum kelloggii Kellogg’s knotweed 1

POPH Polygonum phytolaccaefolium Alpine knotweed <1

PODR Potentilla drummondii Drummond’s cinquefoil <1

POFL1 Potentilla flabellifolia Mount Ranier cinquifoil <1

POGL2 Potentilla glandulosa Sticky cinquefoil 2

POGR4 Potentilla gracilis Slender cinquefoil 1

POPES Potentilla pennsylvanica strigosa Pennsylvania cinquefoil <1

POT2 Potentilla sp. (herb-ann or bien) Cinquefoil <1

PRVUL Prunella vulgaris lanceolata Self-heal <1

PTAQL Pteridium aquilinum lanuginosum Western bracken fern <1

PTAQP Pteridium aquilinum pubescens Western bracken fern 6

PTE1 Pteridium sp. (herb-peren) Bracken fern <1

PTAN Pterospora andromedea Pinedrops 4

PTTEC Pteryxia terebinthina californica Terebinth pteryxia <1

PYMI Pyrola minor English wintergreen <1

PYPI Pyrola picta White-veined wintergreen 18

PYPIA Pyrola picta aphylla White-veined wintergreen 1

PYPID Pyrola picta dentata White-veined wintergreen <1

PYPII Pyrola picta integra White-veined wintergreen 7

PYSE Pyrola secunda Serrated wintergreen 3

RASC3 Raillardella scaposa Green-leaved raillardella <1

RAAL1 Ranunculus alismaefolius Water plantain buttercup <1

RAOC Ranunculus occidentalis Western buttercup <1

RAN1 Ranunculus sp. (herb-ann or bien) Buttercup <1

RONA Rorippa nasturtium Water cress <1

ROSU2 Rorippa subumbellata Tahoe water cress <1

RUAN Rumex angiocarpus Sheep sorrel <1

RUPA1 Rumex paucifolius Alpine sheep sorrel <1

SAGR1 Sanicula graveolens Sierra sanicle <1

SATU Sanicula tuberose Tuberous sanicle <1

SASA3 Sarcodes sanguinea Snow plant 6
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 303

Species Code Scientific Name Common Name Constancy

Forbs, continued

SABR1 Saxifraga bryophora Bud saxifrage <1

SANI1 Saxifraga nidifica Peak saxifrage <1

SAPUA Saxifraga punctata arguta Brook saifrage <1

SCR1 Scrophularia sp. (herb-peren) Figwort <1

SEOB Sedum obtusatum Sierra gormania <1

SESP2 Sedum spathuliforium Pacific stonecrop <1

SEWA2 Selaginella watsoni Alpine selaginella <1

SEAR Senecio aronicoides California butterweed 10

SECA3 Senecio canus Woody butterweed <1

SECL1 Senecio clarkianus Clark’s butterweed <1

SECY Senecio cymbalarioides Rocky mountain butterweed <1

SEIN2 Senecio integerrimus Single-stemmed butterweed 4

SEINM Senecio integerrimus major Single-stemmed butterweed 1

SESE1 Senecio serra Tall butterweed <1

SEN3 Senecio sp. (herb-longevity unk) Butterweed <1

SESP3 Senecio spartioides Narrow-leaved butterweed <1

SETR Senecio triangularis Arrowhead butterweed 3

SIGL Sidalicea glaucescens Glaucous checker 3

SIOR1 Sidalicea oregana Oregon checker 1

SIAP Silene aperta Naked campion <1

SIBR Silene bridgesii Bridge’s campion <1

SIDO1 Silene douglasii Douglas’ campion <1

SIIN Silene invisa Short-petaled campion <1

SILE Silene lemmonii Lemmon’s campion 7

SIMED Silene menziesii dorrii Menzies’ campion <1

SIMO Silene montana Mountain campion <1

SIOC Silene occidentalis Western campion <1

SISA Silene sargentii Sargent’s campion <1

SIL1 Silene sp. (herb-ann or bien) Campion <1

SIVEP Silene verecunda platyota Dolores’ campion <1

SIOF Sisymbrium officinale Hedge mustard <1

SMRA Smilacina racemosa False Solomon’s seal 2

SMRAA Smilacina racemosa amplexicaulis False Solomon’s seal 1

SMRAG Smilacina racemosa glabra False Solomon’s seal 2

SMST Smilacina stellata Nuttall’s Solomon’s seal <1

SOXA Solanum xantii Purple nightshade <1

SOMU Solidago multiradiata Alpine goldenrod <1

SPRU Spergularia rubra Purple sand spurry <1

SPCA Sphenosciadium capitellatum Swamp white-heads 1

STAL Stachys albens White hedge nettle <1

STJA Stellaria jamesiana Sticky starwort 3

STLO1 Stellaria longipes Long-stalked starwort <1

STME Stellaria media Common chickweed <1

STE4 Stellaria sp. (herb-longevity unk) Starwort <1

STLA2 Stephanomeria lactucina Large-flowered stephanomeria 1

STTE Stephanomeria tenuifolia Narrow-leaved stephanomeria 4

STCO4 Streptanthus cordatus Perennial streptanthus <1
304 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Species Code Scientific Name Common Name Constancy

Forbs, continued

STGR2 Streptanthus gracilis Alpine streptanthus <1

STTO Streptanthus tortuosus Mountain streptanthus 4

TAOF Taraxacum officinale Common dandelion <1

THFE Thalictrum fendleri Fendler’s meadow rue 11

TRLO Trifolium longipes Long-stalked clover <1

TRMI2 Trifolium microcephalum Small-headed clover <1

TRMO1 Trifolium monanthum Carpet clover <1

TRI9 Trifolium sp. (herb-ann or bien) Clover 1

TRVAP Trifolium variegatum pauciflorum White-tipped clover <1

VACAC Valeriana capitata californica California valerian <1

VECA1 Veratrum californicum California corn lily 2

VETH Verbascum thapsus Wooly mullein <1

VEALA Veronica alpine alterniflora American alpine speedwell <1

VEAM Veronica americana American brooklime <1

VEPEX Veronica peregrina xalapensis Purslane speedwell <1

VESC2 Veronica scutellata Marsh speedwell <1

VESE Veronica serpyllifolia Thyme-leaved speedwell <1

VICA1 Vicia californica California vetch <1

VIAD Viola adunca Western dog violet 1

VIGL Viola glabella Stream violet <1

VILO Viola lobata Pine violet 1

VILO1 Viola lobata integrifolia Pine violet <1

VIMA2 Viola macloskeyi Macloskey’s violet <1

VIPU Viola purpurea Mountain violet 23

VIO3 Viola sp. (herb-longevity unk) Violet <1

WOOR Woodsia oregana Oregon woodsia <1

WYMO Wyethia mollis Mountain mule-ears 6

Grass and Grass-Like

AGTR1 Agropyron trachycaulum Slender wheatgrass <1

AGEX1 Agrostis exarata Western bent grass <1

AGID Agrostis idahoensis Idaho bent grass <1

AGTH Agrostis thurberiana Thurber’s bent grass 2

AGVA Agrostis variablilis Ross’ bent grass <1

BRBR1 Bromus breviaristatus Short brome 2

BRCA1 Bromus carinatus California brome <1

BRLA1 Bromus laevipes Woodland brome 1

BRMA3 Bromus marginatus Large mountain brome 9

BROR1 Bromus orcuttianus Orcutt’s brome 1

BRRI1 Bromus richardsonii Richardson’s brome <1

BRO1 Bromus sp. (ann or bien) Brome 3

BRO2 Bromus sp. (peren) Brome <1

BRSU Bromus suksdorfii Sudsdorf’s brome 3

BRTE Bromus tectorum Cheatgrass <1

CACA1 Calamagrostis canadensis Blue-joint <1

CAIN1 Calamagrostis inexpensa Narrow-spiked reed grass <1

CAAQ Carex aquatilis Water sedge <1
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 305

Species Code Scientific Name Common Name Constancy

Grass and Grass-Like, continued

CAAT2 Carex athrostachya Slender-beaked sedge <1

CABR5 Carex brevipes Shot sedge <1

CABU1 Carex buxbaumii Buxbaum’s sedge <1

CAEX1 Carex exserta Short-grass sedge <1

CAFE2 Carex feta Green-sheathed sedge <1

CAFI1 Carex filifolia Short-grass sedge <1

CAFR1 Carex fracta Fragile-sheathed sedge 1

CAHA3 Carex hassei Hasse’s sedge <1

CAHE3 Carex heteroneura Various-nerved sedge <1

CAIN3 Carex integra Smooth-beaked sedge <1

CAJE Carex jepsonii Jepson’s sedge 1

CALA3 Carex lanuginosa Wooly sedge <1

CALE3 Carex leporinella Sierra hare sedge <1

CALU1 Carex luzulaefolia Luzula-leaved sedge <1

CALU2 Carex luzulina Luzula-like sedge <1

CAMA1 Carex mariposana Mariposa sedge <1

CAMI1 Carex microptera Small-winged sedge <1

CAMU2 Carex multicostata Many-ribbed sedge 1

CANE2 Carex nervina Sierra nerved sedge <1

CAOC1 Carex occidentalis Sedge <1

CAPA1 Carex pachystachya Thick-headed sedge <1

CAPR2 Carex praegracilis Clustered field sedge <1

CARA1 Carex raynoldsii Raynold’s sedge 1

CARO1 Carex rossii Ross’ sedge 24

CARO2 Carex rostrata Beaked-sedge <1

CASI1 Carex simulata Short-beaked sedge <1

CASP1 Carex specifica Narrow-fruited sedge <1

CASP2 Carex spectablis Showy sedge <1

CASU2 Carex subfusca Rusty sedge <1

CATE1 Carex teneraeformis Sierra slender sedge <1

CATU Carex tumulicola Foothill sedge <1

CAUN1 Carex unilateralis One-sided sedge <1

CAVE2 Carex vesicaria Inflated sedge <1

CAWH Carex whitneyi Whitney’s sedge <1

CAR-1 Carex sp. (longevity unk) Sedge 8

DAIN Danthonia intermedia Mountain wild oatgrass <1

DECA1 Deschampsia caespitosa Tufted hairgrass <1

DEEL Deschampsia elongata Slender hairgrass 2

ELCA1 Elymus canadensis Canadian wildrye <1

ELGL Elymus glaucus Blue wildrye 6

ELGLJ Elymus glaucus jepsonii Jepson’s blue wildrye <1

ELTR Elymus triticoides Alkali rye <1

FES3 Festuca sp. (longevity unk) Bunchgrass <1

FEVI Festuca viridula Mountain bunchgrass 1

GLEL Glyceria elata Tall mannagrass <1

GLST Glyceria striata Mannagrass <1

HOJU Hordeum jubatum Squirreltail <1
306 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

Species Code Scientific Name Common Name Constancy

Grass and Grass-Like, continued

JUBA Juncus balticus Baltic rush <1

JUDR Juncus drummondii Drummond’s rush <1

JUME2 Juncus mertensianus Merten’s rush <1

JUNE Juncus nevadensis Sierra rush <1

JUOX Juncus oxymeris Pointed rush <1

JUPA1 Juncus parryi Parry’s rush 2

JUN2 Juncus sp. (peren) Rush <1

LUCO1 Luzula comosa Common woodrush 5

LUDI Luzula divaricata Forked woodrush <1

LUPA1 Luzula parviflora Small-flowered woodrush <1

LUSP1 Luzula spicata Spiked woodrush <1

MEAR1 Melica aristata Awned oniongrass <1

MEBU Melica bulbosa Western oniongrass 3

MEFU Melica fugax Small oniongrasss <1

MEHA Melica harfordii Harford’s oniongrass 1

MEST Melica stricta Nodding oniongrass <1

METO1 Melica torreyana Torrey’s oniongrass <1

MUFI Muhlenbergia filiformis Slender muhlenbergia <1

MURI1 Muhlenbergia richardsonis Richardson’s muhlenbegia <1

ORHU Oryzopsis hymenoides Indian mountain rice <1

PHAL1 Phleum alpinum Mountain timothy <1

POBO1 Poa bolanderi Bolander’s bluegrass 22

POGR1 Poa gracillima Pacific bluegrass 9

POHA Poa hanseni Leidberg’s bluegrass <1

POIN1 Poa incurva Sandberg’s bluegrass 1

POLE2 Poa leptocoma Bog bluegrass <1

PONE1 Poa nervosa Hooker’s bluegrass 4

PONE2 Poa nevadensis Nevada bluegrass <1

POPR1 Poa pratensis Kentucky bluegrass 1

POSA3 Poa sandbergii Sandberg’s bluegrass <1

POA1 Poa sp. (ann or bien) Bluegrass 4

SIHY Sitanion hystrix Bottle-brush squirreltail 20

SIT Sitanion sp. (peren) Squirreltail <1

STCA1 Stipa californica California needlegrass 9

STCO1 Stipa columbiana Columbia needlegrass 6

STEL1 Stipa elmeri Elmer’s needlegrass 4

STLE1 Stipa lemmonii Lemmon’s needlegrass <1

STNE Stipa nevadensis Needlegrass <1

STOC1 Stipa occidentalis Western needlegrass 18

STPI1 Stipa pinetorum Letterman’s needlegrass 1

STI1 Stipa sp. (peren) Needlegrass 2

TRCEP Trisetum cernuum projectum Nodding oat-grass <1

TRSP1 Trisetum spicatum Downy oat-grass 4

TRSPM Trisetum spicatum molle Downy oat-grass 1

TRWO1 Trisetum wolfii Beardless oat-grass <1
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 307

The total number of individuals of a taxon or taxa in an area or

community. Often measured as cover in plants.

The capacity of soils to hold water available for use by most plants. It is

commonly defined as the difference between the amount of soil water at

field capacity and the amount at the wilting point. It is usually expressed

as inches of water per inch of soil.

The area of the cross section of a tree stem at 41⁄2 feet above the ground on

the high side and inclusive of the bark. Basal area per acre is the sum of

the cross sections of trees at 41⁄2 feet on an acre of land.

A large mass of granitic rock measurable by hundreds of miles long, as

much as a hundred or more miles in width, and formed from the slow

cooling of molten magma several miles below the surface.

One-twelfth of a cubic foot; it represents a rough sawn board 1-foot

square and 1-inch thick. Generally expressed as thousands of board feet

and abbreviated “Mbf.”

A more or less stable biotic community that is in equilibrium with

existing environmental conditions and that represents the terminal stage

of an ecological succession.

Soil particles larger than 2 millimeters in diameter.

The ratio of the number of samples with a species present to the total

number of samples.

The proportion of ground occupied by a vertical projection of the aerial

parts of individuals of the species under consideration.

A volume of rough sawn lumber measuring 12 inches by 12 inches by 12

inches. Generally expressed as thousands of cubic feet and abbreviated

“Mcf.”

The number of plants per unit area such as “trees per acre.”

The diameter of a standing tree measured at 41⁄2 feet above the highest

ground.

A measure of the number of species and their relative abundance in a

community.

A measure of the number of species in a community and their relative

abundance. Such measures include the ratio between number of species

and number of individuals.

Glossary

Available Water Holding

Capacity (AWC)

Basal Area

Batholith

Board Foot

Climax

Coarse Fragments

Constancy

Cover

Cubic Foot

Density

Diameter At Breast

Height (DBH)

Diversity

Diversity Index

Abundance
308 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

The extent that a given species predominates in a community because of

its size, abundance, or coverage and affects the fitness of associated

species.

The ability of soils to retain moisture. For purposes of description, three

drainage classes are used in this guide: excessive, well, and poor.

Excessively drained soils are those that have high hydraulic conductivity

and low water holding capacity; well drained soils are those that retain

optimum amounts of moisture; poorly drained soils are those that are

wet close enough to the surface for long enough periods that vegetative

growth is restricted.

Communities formed by trees with a canopy cover of 61 percent or more

at maturity.

The locality, site, and particular type of local environment occupied by

an organism.

Communities dominated by grass, grass-like, or forb vegetation with or

without a tree or shrub component at maturity. The tree or shrub canopy

cover is 25 percent or less at maturity.

A diversity index value that is used to characterize species abundance

relationships in communities.

A habitat characterized by an abundance of moisture available for the

support of plants.

A measure of overall importance of a given species in a community. It is

calculated as the sum of relative frequency, relative density, and relative

dominance.

The characteristic structural features and method of survival of a plant

species.

A habitat characterized by a moderate amount of moisture available for

the support of plants. Neither hydric nor xeric.

Small scale irregularity of the land surface.

That portion of the trees in a forest stand forming the upper crown

cover. The topmost layers in a forest community.

A potential natural plant community of definite floristic composition,

representing a uniform appearance and occurring within uniform habitat

conditions. Associations are groupings of plants that have attained

dynamic equilibrium with local existing environmental conditions.

Future plant communities are unpredictable in the absence of major

disturbance. They are conventionally named for conspicuous dominant

or codominant species in different vegetation layers. A diagnostic

indicator species may be used in the association name to provide a

clearer link between the association characteristic and the name.

Dominance

Drainage

Forest

Habitat

Herbaceous Vegetation

Hill Numbers

Hydric

Importance Value

Life Form

Mesic

Microrelief

Overstory

Plant Association
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 309

An assemblage of plants living and interacting together in a specific

location. No particular ecological status is implied.

The biotic community that would be established if all successional

sequences of its ecosystem were completed without additional humancaused disturbance under existing environmental conditions. Grazing

by native fauna, natural disturbances such as drought, floods, wildfire,

insects, and disease are inherent in the development of potential natural

communities that may include naturalized non-native species.

The breast height diameter of the tree of average basal area. The average

stand diameter weighted by basal area.

Tree seedlings or saplings smaller than 1-inch DBH.

A succession of plant communities in a given habitat leading to a

particular climax association. A stage in a community succession.

The developmental stages of an ecological succession.

An aggregation of taxonomically related plant associations named for

the late seral stage species that dominate or have the potential to

dominate the principal vegetative layer in a time frame appropriate for

the vegetation under consideration. Generally, in this classification,

series were named for the tree species with highest average total cover.

Communities composed of woody perennial shrubs less than 16 feet tall

at maturity with 26 percent or more canopy cover. A tree canopy cover

25 percent or less may be present.

A diversity index value that is used to characterize species abundance

relationships in communities (cf Methods).

A location, place, or position in respect to physical surroundings. An

area considered as to its ecological factors with reference to capacity to

produce forests or other vegetation.

An expression of forest site quality based on the height of the dominant

trees at an arbitrarily chosen age.

A standing dead tree from which the leaves have fallen.

The ratio of the total annual potential solar insolation on a particular

slope to the maximum annual potential solar insolation at the same

location. It compares total potential solar radiation at a site with the

potential radiation at the same site after adjusting for latitude, aspect,

and percent slope.

An aggregation of trees or other vegetation occupying a specific area

and sufficiently uniform in species composition, age arrangement, and

condition as to be distinguishable from the forest or other vegetation on

adjoining areas.

Plant Community

Potential Natural

Community

Quadratic Mean Diameter

Regeneration

Sere

Seral Stage

Series

Shrubland

Simpson Index

Site

Site Index

Snag

Solar Radiation Index

(SRI)

Stand
310 USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998.

The average age of the dominant or codominant trees that compose a

stand.

The ratio of the number of trees in a stand of a certain average diameter

to the number of trees in a fully stocked stand of the same diameter. The

Reinecke stand density index is used in this study. It is independent of

species, site quality, and age. It is used as a measure of stocking for

stands of similar diameter.

An index value used to describe the moisture conditions of a site by

integrating the available water holding capacity, the solar radiation

index, elevation, and slope position.

An aggregation of taxonomically related plant associations within a

series that takes the name of that series followed by related species that

are codominant or have indicator value across multiple plant associations

(Pacific Southwest Region, USDA Forest Service).

The layers of soil beneath the topsoil and overlying the bed rock.

The replacement of one community by another. The gradual process of

community change and replacement leading to a stable climax

community. The process of continuous colonization and extinction of

species populations at a particular site.

The upper soil layer or layers containing some organic matter.

The vegetation in a forest stand below the overstory. The vegetation

layers between the overstory and the ground. In this classification all

trees smaller than 1-inch DBH are considered understory.

Communities composed of trees with a canopy cover of 26 to 60 percent

at maturity.

A habitat characterized by low or deficient amounts of moisture available

for the support of plant life.

Stand Age

Stand Density Index

Stress Index

Subseries

Subsoil

Succession

Topsoil

Understory

Woodland

Xeric
USDA Forest Service Gen.Tech.Rep. PSW-GTR-169. 1998. 311

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