United States 

Department of Agriculture

Forest Service

Pacific Northwest 

Research Station

General Technical Report

PNW-GTR-641

August 2005

Bunchgrass Plant Communities of 

the Blue and Ochoco Mountains: 

A Guide for Managers

Charles Grier Johnson, Jr., and David K. Swanson
The Forest Service of the U.S. Department of Agriculture is dedicated to the principle of multiple use management of the Nation’s forest resources for sustained yields of wood, water, forage, wildlife, and recreation. 

Through forestry research, cooperation with the States and private forest owners, and management of the 

national forests and national grasslands, it strives—as directed by Congress—to provide increasingly greater 

service to a growing Nation.

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basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, 

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Avenue, SW, Washington, DC 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is 

an equal opportunity provider and employer.

Authors

Charles Grier Johnson, Jr. was the area ecologist (retired), and David K. Swanson is the 

area ecologist for the Malheur, Umatilla, and Wallowa-Whitman National Forests, 1550 

Dewey Avenue, Baker City, OR 97814.

Cover photograph: Bluebunch wheatgrass near Bean Creek, Hells Canyon National 

Recreation Area.

Unless otherwise noted, all photographs were taken by Charles G. Johnson.
iii

Abstract

Johnson, Charles Grier, Jr.; Swanson, David K. 2005. Bunchgrass plant communities of 

the Blue and Ochoco Mountains: a guide for managers. Gen. Tech. Rep. PNW-GTR-641. 

Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research 

Station. 119 p.

A classification of bunchgrass vegetation is presented for the Malheur, Ochoco, Umatilla, 

and part of the Wallowa-Whitman National Forests. It includes grassland vegetation as well 

as shrubland and forest land where the herbaceous layer is dominated by bunchgrasses. It is 

based on potential vegetation, with the plant association as the basic unit. Diagnostic keys and 

descriptions are presented for each type. Descriptions include information about plant species 

occurrence, environment and soils, states and transitions, forage productivity, management 

considerations, and relationships to other classifications.

Keywords: Blue Mountains, Ochoco Mountains, plant association, plant ecology, range 

management, steppe.
iv

Contents

 1 Introduction

 1 What Is a Bunchgrass?

 1 History of Bunchgrasses and Livestock Grazing in the Pacific Northwest

 2 Study Area

 2 Physiography and Geology

 2 Climate

 4 Soils

 4 Vegetation Overview

 4 Plant Association Concept

 5 State-and-Transition Concept

 5 Phases and States

 6 Fire Regimes and Fire Effects

 6 Ponderosa Pine Forest

 6 Juniper Woodlands

 6 Shrublands

 7 Grasslands

 8 The Spread or Decline of Woody Plants

 8 Newcomers to Bunchgrass Communities

 9 Indicator Species

 9 Sampling and Field Methods

 10 Classification and Data Analysis Methods

 10 Use of the Management Guide

 10 Cover Percentages

 10 Estimating Cover

 11 Format of the Vegetation Type Descriptions

 12 Keys for Determining the Bunchgrass Plant Associations and 

 Plant Community Types

 12 Limitations in the Use of the Keys

 12 Rules for Use of the Keys

 12 Key to Series

 13 Key to Ponderosa Pine Series Vegetation

 13 Key to Western Juniper Series Vegetation

 14 Key to Shrubland Vegetation

 16 Key to Grassland Vegetation

 18 Ponderosa Pine Series

 18 PIPO/CELE3/FEID-AGSP Plant Association (CPS234)

 20 PIPO/CELE3/PONEW Plant Association (CPS233)

 21 PIPO/PUTR2/FEID-AGSP Plant Association (CPS226)

 22 PIPO/PUTR2/AGSP-POSA12 Plant Association (CPS229)

 24 PIPO/ARTRV/FEID-AGSP Plant Association (CPS131)

 26 PIPO/FEID Plant Association (CPG112)

 28 PIPO/AGSP Plant Association (CPG111)

 29 PIPO/PERA4 Plant Community Type (CPS8)

 29 PIPO-JUOC/CELE3-SYOR2 Plant Community Type (CPC212)

 30 Western Juniper Series

 30 JUOC/CELE3/FEID-AGSP Plant Association (CJS41)

 32 JUOC/PUTR2/FEID-AGSP Plant Association (CJS321)

 34 JUOC/ARAR8/FEID Plant Association (CJS112)

 35 JUOC/FEID-AGSP Plant Association (CJG111)

 36 JUOC/ARRI2 Plant Community Type (CJS811)

 36 JUOC/AGSP Plant Community Type (CJG113)
v

 37 Shrubland Series

 37 CELE3/FEID-AGSP Plant Association (SD4111)

 38 CELE3-PUTR2/AGSP Plant Community Type (SD4115)

 38 CELE3/AGSP Plant Community Type (SD4112)

 39 CELE3/PONEW Plant Community Type (SD4114)

 39 PUTR2-ARTRV/FEID-AGSP Plant Association (SD3124)

 41 PUTR2/FEID-AGSP Plant Association (SD3111)

 42 PUTR2-ARTRV/FEID Plant Community Type (SD3125)

 42 PUTR2/ERDO Plant Community Type (SD3126)

 43 ARTRV/FEID-KOCR Plant Association (SD2929)

 45 ARTRV/FEID-AGSP Plant Association (SD2911)

 47 ARTRV/AGSP-POSA12 Plant Association (SD2918)

 48 ARTRV-SYOR2/BRCA5 Plant Community Type (SD2917)

 48 ARTRV-SYOR2 Plant Community Type (SD2919)

 49 ARTRV/BRCA5 Plant Community Type (SS4914)

 49 ARTRV-PERA4 Plant Community Type (SD3010)

 49 ARTRV/ELCI2 Plant Community Type (SD3011)

 50 ARAR8/FEID-AGSP Plant Association (SD1911)

 52 ARAR8/AGSP Plant Association (SD1924)

 54 ARAR8/POSA12 Plant Association (SD9221)

 55 ARRI2/POSA12 Plant Association (SD9111)

 57 ARRI2/PEGA Plant Community Type (SD9141)

 57 ARTRT4/POSA12-DAUN Plant Community Type (SD2401)

 57 SYOR2 Plant Community Type (SM32)

 57 BERE/AGSP-APAN2 Plant Community Type (GB4915)

 58 Grassland Series

 58 Green Fescue Communities (FEVI-LULA3, FEVI-JUPA, FEVI-PENST)

 58 FEID-GETR Plant Community Type (GB5923)

 59 FEID-AGSP-CYTEF Plant Association (GB5925)

 60 FEID-AGSP-FRALC2 Plant Association (GB5926)

 61 MEBU-STOC2 Plant Community Type (GB5011)

 61 STOC2-SIHY (Alpine) Plant Community Type (GS50)

 62 FEID-KOCR (Mound) Plant Association (GB5912)

 64 FEID-KOCR (Ridge) Plant Association (GB5911)

 66 FEID-AGSP-LUPIN Plant Association (GB5916)

 67 FEID-AGSP-BASA3 Plant Association (GB5917)

 69 FEID-AGSP-PHLOX Plant Association (GB5931)

 71 FEID-AGSP Plant Association (GB59)

 72 FEID-DAUN Plant Community Type (GB5932)

 73 AGSP-POSA12-LUPIN Plant Association (GB4119)

 75 AGSP-POSA12-BASA3 Plant Association (GB4123)

 77 AGSP-POSA12-ERHE2 Plant Association (GB4124)

 78 AGSP-POSA12-ASRE5 Plant Association (GB4125)

 80 AGSP-POSA12-TRMA3 Plant Association (GB4126)

 82 AGSP-POSA12-SCAN3 Plant Association (GB4112)

 83 AGSP-POSA12-APAN2 Plant Association (GB4127)

 84 AGSP-POSA12-DAUN Plant Association (GB4911)

 86 AGSP-POSA12 Plant Association (GB4121)

 87 AGSP-BRCA5 Plant Community Type (GB4131)

 88 AGSP-ERUM Plant Community Type (GB4132)

 88 AGSP-CYTEF Plant Community Type (GB4133)

 88 ERDO-POSA12 Plant Community Type (FM9111)

 88 POBU-MAGL2 Plant Community Type (GB4411)
vi

 89 DAUN-LOLE2 Plant Association (GB9114)

 91 POSA12-DAUN Plant Association (GB9111)

 93 Glossary

 94 Acknowledgments

 94 Metric and English Equivalents

 94 References

 98 Appendix A: Plants Listed by Life Form and Scientific Name

 108 Appendix B: Plants Listed by Common Name

 118 Appendix C: Vegetation Types by Ecoclass Code
1

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Introduction

This management guide is provided for use in determining the bunchgrass plant associations and plant community types encountered on lands administered by the Malheur, 

Ochoco, Umatilla, and Wallowa-Whitman National Forests 

(NF) within the Pacific Northwest Region (Region 6). Classification of new plots along with bunchgrass plots included in Plant Associations of the Blue and Ochoco Mountains 

(Johnson and Clausnitzer 1992) provide the basis of this 

study. The purpose of this publication is to provide the field 

investigator with floristic indicator species that are diagnostic of a particular environment and potential vegetation.

Successional relationships and disturbance effects are 

portrayed by using the state-and-transition approach 

(Westoby et al. 1989), following the current trend in scientific thinking. This way of describing vegetation change on 

rangelands has largely replaced the successional model, in 

which ecological status was described as late seral, mid seral, or early seral based on an assumed successional pathway toward potential natural vegetation. The successional 

model in turn provided an alternative to the earlier condition classes of “good,” “fair,” and “poor” based on suitability for domestic livestock grazing. To assist in conversion to 

the state-and-transition model, the user might consider the 

phases in a state-and-transition model as analogous to seral stages or condition classes, and the transitions as multiple 

pathways between them resulting from succession or disturbance by grazing, fire, and so forth.

What Is a Bunchgrass?

Grasses belong to the grass family Poaceae (Gramineae). 

Bunchgrasses are those grasses that have the characteristic 

growth habit of a clump, tuft, or bunch, in contrast to sodforming grasses that spread via stolons or rhizomes. Bunchgrasses have fibrous root systems that occupy a belowground 

area approximating the aboveground foliar canopy. Studies 

by John Ernst Weaver (1915) gave us the first overall picture 

of the bunchgrass plant—above and below ground—by exhuming them carefully. The rooting depths of our principal 

bunchgrasses are linked to the environments they occupy. 

Following are key bunchgrasses (see apps. A and B for a 

full list of scientific and common names of species) and a 

description of their adaptations to some of the harshest 

sites in eastern Oregon:

Sandberg’s bluegrass (Poa sandbergii, syn. P. secunda)—

This plant relies on lateral roots (3 to 5 in long) to utilize 

surface soil moisture, with deep roots extending down only 

8 in. The root structure explains the plant’s ability to occupy droughty scabland sites. Surface soil moisture is depleted 

more rapidly than moisture in deeper layers, and thus Sandberg’s bluegrass usually matures and dries up earlier than 

more deep-rooted bunchgrasses (Sauer and Uresk 1976). 

Short stature and a brief green period make this grass highly 

resistant to grazing.

Idaho fescue (Festuca idahoensis)—This deep-rooted 

bunchgrass extends to an average depth of 18 in. Because 

this is not a great depth for bunchgrass, Idaho fescue requires relatively moist sites.

Prairie junegrass (Koeleria cristata syn. K. macrantha)—

Similar to Idaho fescue in site requirements, the roots of 

this grass extend downward about 15 in.

Bluebunch wheatgrass (Agropyron spicatum, syn.

Pseudoroegenaria spicata)—This tenacious bunchgrass 

has roots that extend to an average depth of 4 ft, allowing 

it to occupy some of the driest and hottest sites in eastern 

Oregon. Bluebunch wheatgrass is a very nutritious grass 

that is relished by livestock and wildlife. It is, however, 

easily damaged if grazed heavily during its period of active 

growth (Blaisdell and Pechanec 1949, Miller et al. 1986).

Most bunchgrasses in our region are cool-season grasses; 

they accomplish most of their growth during cooler, moister weather before the summer drought. Most cool-season 

grasses are able to grow in the fall if rains occur, go dormant during the winter, then resume growth in early spring. 

They complete their yearly growth and go to seed before 

the extreme drought of late summer begins. Warm-season 

grasses, which grow mainly during midsummer, occur at 

low elevations in the Hells Canyon region (see Johnson and 

Simon 1987) but were not recorded on the plots used in this 

study.

History of Bunchgrasses and Livestock 

Grazing in the Pacific Northwest

Early European explorers gave vivid accounts of the bunchgrass landscape they encountered prior to the arrival of European settlers (the following quotes are from McArdle and 

Costello 1936). In 1841 Commander Wilkes wrote from 

north central Oregon: “These hills, as well as the country 

nearer at hand, were covered with a natural hay or bunchgrass, which affords very nutritious food for cattle.” Captain Fremont wrote when passing through eastern Oregon in 

1843: “The mountains were covered with good bunchgrass.” 

Granville Stuart wrote 

We crossed the Rocky Mountain Divide on the 10th

day of October, 1857. As soon as we had crossed 

the divide a wonderful change appeared in the 

country. Instead of the gray sagebrush covered 

plains of Snake River, we saw smooth rounded hills 

and sloping benchland covered with yellow bunchgrass that waved in the wind like a field of grain.
2

GENERAL TECHNICAL REPORT PNW-GTR-641

Grazing by domesticated livestock in the Blue Mountains 

began with Indian horses in the 1700s, but widespread impacts began with expansion of cattle and sheep ranching after 1870 (Galbraith and Anderson 1971, Humphrey 1943). 

Numbers of cattle and sheep peaked around 1900. This was 

a time of true open range, with no government regulation of 

numbers of animals, season of use, or which livestock owners were entitled to use the land. Today we still observe areas with grazing-resistant and invasive weedy species on 

sites that we believe should support bunchgrass vegetation; 

these are former livestock driveways or bedding areas from 

the early 1900s. Livestock numbers declined after 1906 as 

the USDA Forest Service began to regulate grazing through 

its allotment system. Livestock grazing, primarily by cattle, 

continues to this day on most bunchgrass-dominated plant 

communities in the Blue Mountains.

Study Area

The Blue and Ochoco Mountains of eastern Oregon are 

part of the Blue Mountains physiographic province (Orr 

and Orr 1999). This broad area includes the Ochoco 

Mountains to the west; the Strawberry, Aldrich, and Greenhorn Mountains in the southern part of the Blue Mountains; 

the Elkhorn Mountains and the tristate uplands of the northern Blue Mountains; and the Wallowa Mountains on the east 

end of the province (fig. 1). The Blue Mountains segment 

is a northeast- to southwest-trending axis of geologically 

old mountains that extend south from Pomeroy, Washington, 200 mi to the south near Burns, Oregon. A 50-milelong spur begins west of Ukiah, Oregon, with an east-west 

axis toward Fossil, Oregon. The Ochoco Mountains are another east-west trending axis of ridges that begin west of 

the Aldrich Mountains near Dayville, Oregon, and culminate north of Prineville, Oregon. The study was conducted 

on USDA Forest Service-administered land, including the 

mountains and intervening canyons in the Malheur, Ochoco, 

Umatilla, and Wallowa-Whitman NF. Additional plots were 

installed on the Crooked River National Grasslands between 

Prineville and Madras, Oregon.

The study area was divided into four segments to assist in 

portraying the distribution of vegetation as described in this 

management guide. These segments are as follows with key 

physiographic features listed:

1. Northern Blue Mountains—North of Interstate 84 

(running between La Grande and Pendleton)

• High points—Oregon Butte ( 6,401 ft) and 

Mount Emily (6,064 ft)

• Low points—Tucannon River, Umatilla River, 

Wenaha River

2. Central Blue Mountains—South of Interstate 84 and 

north of U.S. Highway 26 (running between Unity 

and John Day).

• High points—Vinegar Hill (8,131 ft) and Rock Creek 

Butte (9,106 ft)

• Low points—Powder River, Grande Ronde River, 

North Fork John Day River

3. Southern Blue Mountains—South of U.S. Highway 26

• High points—Strawberry Mountain (9,038 ft) and 

Fields Peak (7,363 ft)

• Low points—South Fork John Day River, Malheur 

River

4. Ochoco Mountains

• High points—Round Mountain (6,753 ft) and 

Spanish Peak (6,885 ft)

• Low points—Crooked River

Physiography and Geology

The study area is dominantly an extensive lava plateau at 

elevations of 3,500 to 6,500 ft, punctuated by a few deep 

canyons, with elevations as low as 2,000 ft, and mountains 

rising to about 9,000 ft. Most bunchgrass communities here 

occur over volcanic rocks that erupted during the Cenozoic 

Era—primarily basalt, but also andesite and rhyolite. 

Interbedded in these volcanic rocks are some relatively 

thin layers of tuffaceous sedimentary rocks. Locally in the 

southern half of the study area, the older sedimentary and 

metasedimentary rocks that occur beneath the volcanics are 

exposed. These consist mostly of graywacke, shale, and 

argillite deposited in a marine environment. Included with 

these sedimentary rocks in a few places are ultramafic 

rocks, including serpentine, that originated as deep ocean 

crust. These ultramafic rocks occur in environments with 

bunchgrass vegetation in the Strawberry Mountains and in 

the vicinity of Mine Ridge southwest of Unity, Oregon. One 

large area of granitic rock also occurs in the study area—the 

Bald Mountain batholith—which is centered in the vicinity 

of Anthony Lakes, northwest of Baker City, Oregon. This 

high-elevation area has only incidental occurrences of 

bunchgrass vegetation. (This section is based on Orr and 

Orr 1999 and Walker and McLeod 1991.)

Climate

The climate of bunchgrass plant communities in the Blue 

Mountain region is temperate and semiarid (USDA NRCS 

2004a, Western Regional Climate Center 2004). Precipitation is highly seasonal, with most arriving between November and June; drought conditions are common in late 

summer. Temperatures generally decrease with increasing 

elevation, although low temperature extremes in all seasons 

tend to occur at moderate elevations on valley bottoms 

surrounded by higher terrain. Summer highs are typically 

in the high 70s and 80s °F, and lows in the 40s. Winter 

highs average in the 30s °F and lows in the teens. Summer 
3

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

temperatures in the 90s °F are not unusual, and winter 

temperatures occasionally fall below 0 °F. The lowest 

temperature ever recorded in Oregon or Washington (-54 °F) 

was recorded at both Seneca and Ukiah, not far from our 

bunchgrass study plots. Precipitation is generally lower in 

the south and at lower elevations in our study area. At lower 

elevations (2,000 to 3,000 ft in the north and 4,500 to 5,000 

ft in the south), where bunchgrass communities occur on a 

variety of sites, annual precipitation averages between 10 

and 20 in. Stations at higher elevations in the vicinity of 

bunchgrass communities have annual precipitation of 20 to 

40 in, but effective precipitation on sites where bunchgrass 

communities actually occur is typically reduced by wind, 

which removes snow in winter, and intense solar radiation 

on steep southerly aspects, which greatly increases evaporation.

Daubenmire (1956) investigated in detail the relationship 

of climate to several of the vegetation series that are classified here. The zone dominated by sagebrush with bluebunch wheatgrass is generally drier and has colder winters 

than bluebunch wheatgrass areas without sagebrush, although no simple statistic defines that boundary. The transition from the sagebrush to ponderosa pine zone occurs at 

mean annual precipitation values of about 15 in. The bluebunch wheatgrass and Idaho fescue zones show considerable overlap in precipitation, but the latter are consistently 

cooler (which reduces drought severity) and in some cases 

have higher precipitation also. The July mean temperature 

in all of Daubenmire’s bluebunch wheatgrass zone stations 

was greater than 70 °F, as opposed to less than 70 °F in the 

fescue zone. Note that local site characteristics often allow a 

vegetation type to occur outside of its zone as determined by 

the macroclimate.

������

Pomeroy

Walla Walla

Pendleton

La Grande

Enterprise

Ukiah

Baker City

Unity

John 

 Day Dayville

Seneca

Burns

Prineville

Madras

26

Fossil

84

Heppner

Sample plots

National forest

O R E G O N

0 25 50 Miles

Figure 1—Location of the study area.
4

GENERAL TECHNICAL REPORT PNW-GTR-641

Soils

Soils of bunchgrass plant communities are a mixture of 

loess, volcanic ash, and weathered bedrock. The parent 

materials are noncalcareous, and basalt is the most common 

lithology. Most soils have little or no stone-free loamy 

material at the surface, and coarse fragments increase with 

depth, reaching bedrock or extremely gravelly/cobbly 

material within about 2 ft of the surface. A common soil 

class is Lithic Argixerolls, which are soils with a brown 

surface layer rich in organic matter from herbaceous 

understory plants (a mollic epipedon), a seasonally dry 

(xeric) moisture regime, a clay-enriched subsoil horizon 

(an argillic horizon), and bedrock near the surface (a lithic 

contact). Where bedrock is very close to the surface, one 

or both of the horizons mentioned above may be missing, 

resulting in Lithic Haploxerolls (soils where the clay subsoil 

is thin or absent) or Lithic Xerorthents (soils where both the 

clay subsoil and brown surface layer are thin or absent). For 

more information on these soil classification terms see 

USDA NRCS (1998).

On level to gently sloping sites with shallow soils, both 

the clay-rich subsoil and underlying bedrock retard infiltration of spring meltwater, resulting in temporary soil saturation. However, as a result of the dry summer climate and the 

low available water capacity of these soils, soil moisture is 

depleted during the summer. These strongly contrasting soil 

moisture conditions present a special challenge for plants, 

and the result is sparse vegetation of stiff or low sagebrush 

(Artemisia rigida or A. arbuscula), Sandberg’s bluegrass 

(Poa sandbergii), onespike oatgrass (Danthonia unispicata), 

and occasionally rushes (Juncus spp.).

On soils with better drainage, thanks to a sloping surface, 

well-fractured bedrock, or gravelly colluvial parent material, spring saturation is not a problem, but summer depletion 

of soil moisture is ubiquitous. Plant communities are strongly dependent on the severity of drought as determined by 

the interaction between macroclimate (i.e., precipitation and 

temperature), soil climate/microclimate (as determined by 

slope aspect and steepness, and wind deflation of snow), and 

soil moisture-holding capacity. Thus a plant species may be 

restricted to deeper soils near the climatically dry limit of its 

range.

Vegetation Overview

Climate, elevation, aspect, soils, and disturbance all influence vegetation. In the Blue and Ochoco Mountains, temperature and moisture are fundamental determinants of 

where plant species grow. The bunchgrass vegetation series 

can be arrayed according to their moisture and temperature 

adaptations from “cool, moist” to “hot, dry” as follows:

 FOREST

 Ponderosa pine/bunchgrass

 Western juniper/bunchgrass

 SHRUBLANDS

 Mountain mahogany/bunchgrass

 Bitterbrush/bunchgrass

 Mountain big sagebrush/bunchgrass

 Low sagebrush/bunchgrass

 Stiff sagebrush/bunchgrass

 GRASSLANDS

 Green fescue (subalpine)

 Idaho fescue (subalpine)

 Idaho fescue (montane)

 Bluebunch wheatgrass

 Onespike oatgrass

 Sandberg’s bluegrass

The temperature and moisture environment for plant 

growth is determined by the combination of climate (strongly influenced by elevation) and local soil/site conditions. For 

example, a site at low elevation with very shallow soils will 

be dry for most of the growing season and might support 

stiff sagebrush or Sandberg’s bluegrass series vegetation. 

A site at higher elevation, on a deeper soil, or on north aspects is cooler and moister and may sustain ponderosa 

pine or Idaho fescue series vegetation.

Plant Association Concept

In this study we sampled existing vegetation and the 

environmental attributes of each site to help identify the 

potential natural vegetation, which in turn was used to 

define plant associations. Existing vegetation is the plant 

cover, floristic composition, and vegetation structure 

occurring at a given location at the current time (Winthers 

et al. 2004). Potential natural vegetation (PNV) is that 

plant community that would become established if all 

successional sequences were completed without human 

interference under the present environmental and floristic 

conditions, including those created by man (Winthers et al. 

2004). Historical vegetation is that vegetation believed to 

have existed in the study area prior to the impact made by 

Euro-Americans beginning about 1850 (USDA Forest 

Service 2003). Prior to the arrival of Euro-Americans, the 

primary disturbance agents on bunchgrass sites were fire 

(including fire caused by Native Americans), wild ungulates, small animals, insects, diseases, and slope-driven soil 

movements. As a result of these disturbance factors, 

historical vegetation did not consist entirely of late-successional vegetation; in other words, historical vegetation is not 

synonymous with PNV. Instead the historical vegetation 

landscape generally contained a mix of vegetation communities resulting from disturbance events. The historical 
5

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

range of variability represents this mix of different seral 

conditions that are believed to have occurred in the historical vegetation.

This publication uses the conventions for classifying potential vegetation that have been in use in Region 6 of the 

Forest Service for several decades. The plant association,

the fundamental unit of classification, is identified by determining the potential vegetation of a site. Plant associations 

are named by using both dominant late-seral overstory species and other species that indicate environmental conditions 

such as moisture supply and temperature. A plant association includes the relatively rare pristine late-seral vegetation 

for which it is named and all the disturbed and early seral 

vegetation that would succeed to it.

This definition differs somewhat from the usage of “plant 

association” in the National Vegetation Classification System (Jennings et al. 2003) and the USDA Forest Service 

Terrestrial Ecological Unit Inventory Technical Guide

(Winthers et al. 2004), where plant associations are units 

in the classification of existing vegetation. Our concept of 

a plant association is similar to the “habitat type” concept 

used in Forest Service Northern Region (Region 1) (Pfister 

and Arno 1980). The habitat type is a unit of land classified 

as capable of supporting a specific plant association.

The plant community type is a less formal vegetation 

type, simply an aggregation of plant communities with floristic and structural similarities (Society for Range Management 1989). We established plant community types to 

describe (1) highly disturbed communities where the PNV 

could not be determined, and (2) possible plant associations 

where our sample size was too small to adequately understand the range of variation.

Series are aggregations of plant associations and plant 

community types based on the dominant overstory plants. 

For example, bunchgrass vegetation that occurs with an 

overstory of big sagebrush is placed in the big sagebrush 

series.

The concept of potential natural vegetation can become 

confusing where communities have been greatly altered 

from the historical condition. Two problematic situations 

are particularly common: (1) juniper invasion and (2) replacement of bunchgrasses by introduced species such as 

cheatgrass. In the first case, many sites that historically were 

treeless will succeed to juniper woodland if a seed source 

is available and they are protected from fire. We classify 

shrubland or herbland vegetation into shrubland or herbland plant associations if they currently have few or no trees, 

even if they could theoretically support junipers. Once junipers have become established, we classify the vegetation 

into a juniper plant association, even if historically junipers 

were absent (and we note the latter fact in the plant association description). Secondly, in some cases, severe disturbance combined with invasion by nonnative plants has 

produced communities that no longer would succeed naturally back to the PNV. If the PNV can be determined, these 

communities are classified into a plant association. In a few 

cases where the PNV cannot be identified, we have established plant community types to accommodate them.

State-and-Transition Concept

This study portrays the condition and successional status of 

vegetation by the state-and-transition model (Westoby et al. 

1989). According to this model, the vegetation present on a 

given site is determined by complex interactions of the 

history of disturbance, climate, management, and availability of propagules (e.g., seed). Vegetation is modeled 

as a set of states or phases, and transitions describe how 

vegetation can change from one state to another. Examples 

of transition agents include fire, succession, grazing, and 

invasion by exotic plant species. This model has largely 

superseded the range succession model (Dyksterhuis 1949) 

in range management.

In current usage, “phases” are separated from one another 

by transitions, most of which are reversible. Phases are separated into “states” when a transition crosses an ecological 

threshold that is nearly irreversible (Laycock 1991, Stringham and Kreuger 2001). For example, overgrazing may reduce cover by native grasses somewhat, but after a change 

in grazing regime the bunchgrasses might recover their former dominance; the pristine and somewhat degraded communities would then be considered two phases of a single 

state. If degradation were to proceed to the point where the 

native grasses were eliminated and were replaced by highly 

competitive exotic grasses that would persist even if grazing 

ceased, then a threshold would be crossed and transition to 

a new state would have occurred.

Phases and States

Plant associations were subdivided into phases and states 

that represent significantly different cases from the perspective of ecology and management. For a given plant association we typically recognized four phases of vegetation as 

follows:

A Relatively pristine vegetation close to the hypothetical 

PNV. For some shrubland plant associations with adequate data we were able to subdivide the A phase into 

a transient postfire phase (A1) and a late-successional 

phase with larger and older shrubs (A2).

B Vegetation that has been moderately altered by grazing, 

such that certain grazing-sensitive species have been affected but are still present in substantial amounts.

C Vegetation that has been greatly altered by grazing but 

still retains native species in sufficient amounts that 

they could presumably recover to approximate the PNV 

phase given sufficient time. Some plant associations had 
6

GENERAL TECHNICAL REPORT PNW-GTR-641

more than one phase of this kind (C1, C2, etc.): e.g., a 

phase where bunchgrasses have been partly replaced by 

exotic annuals vs. a phase where they have been partly 

replaced by grazing-resistant perennial forbs. The authors believe that C phases represent communities in 

peril of crossing a threshold into a new state via loss of 

native species, invasion of other species, or soil erosion.

D Vegetation that has been altered by loss of native species 

and invasion of exotics to the point that succession back 

to the original PNV is now unlikely and a new state has 

been established. For some plant associations there are 

more than one of these phases (D1, D2, etc.), depending 

on what invasive species has gained dominance.

Thus A, B, and C represent different phases within a single state (fig. 2). Transitions between them are caused by 

heavy grazing, succession, and fire, and are believed to be 

reversible. The D phases are separated by an ecological 

threshold from the others and thus belong to a different state. 

This threshold is formed by loss of native species, invasion 

of exotic plants, soil erosion, or some combination of these 

factors. There may also be thresholds separating some of the 

D phases from one another, but we have not studied these 

transitions in detail.

Fire Regimes and Fire Effects 

Fire has historically been an important natural disturbance 

process in bunchgrass communities and remains so today. 

Historical fire frequency is difficult to determine in bunchgrass vegetation because of the lack of trees that could provide a record of fires. Fire effects and postfire succession in 

this region are fairly well known thanks to local monitoring 

(see Johnson 1998b, Swanson 2005, and USDA Forest Service 2005 for more information) 

Ponderosa Pine Forest

Considerable fire history work has been done in ponderosa 

pine forests, including locally in the Blue Mountains 

(Heyerdahl et al. 2001). These studies generally agree that 

ponderosa pine forests historically had frequent light 

underburns, with a return interval of about 10 to 20 years 

(Heyerdahl et al. 2001) or even less (Brown and Smith 

2000). However, nearly all of these studies have been in 

more mesic pine communities, such as those with an 

understory of pinegrass (Calamagrostis rubescens), elk 

sedge (Carex geyeri), or snowberry (Symphoricarpos spp.), 

and not in pine forests with a bunchgrass understory. The 

exception is Miller and Rose’s (1999) study in south-central 

Oregon of fire scars on scattered pines in bunchgrass 

ecosystems that were being invaded by juniper. This study 

showed fire-return intervals of 12 to 15 years, i.e., not unlike 

the moister pine sites. Note that such short fire-return 

intervals would make survival of young pines a very rare 

event. A few investigators believe that methodological 

problems have led us to underestimate fire-return intervals 

in pine, and that they could actually have been much longer 

(e.g., Baker and Ehle 2001).

The frequent light underburns of pines probably caused 

little tree mortality except for seedlings and saplings, but 

consumed much of the understory biomass. Fire effects on 

the understory vegetation are similar to those of analogous 

treeless vegetation types discussed below.

Juniper Woodlands

Available evidence suggests that low-severity underburns 

are not common in these woodlands and that most fires kill 

the trees (Baker and Shinneman 2004). Juniper woodlands 

in our study area include (1) woodlands that contain old 

trees and probably existed before the change in fire regimes 

that accompanied European settlers and (2) woodlands that 

are the result of postsettlement juniper invasion (Burkhardt 

and Tisdale 1969, Miller and Rose 1995, Young and Evans 

1981).

The juniper woodlands where juniper has probably been 

present for many centuries contain old trees and are primarily in environments with little fuel because of shallow, 

droughty soils. In our classification, these are the JUOC/

CELE3/FEID-AGSP, JUOC/ARAR8/FEID, JUOC/ARRI2, 

and JUOC/AGSP types. Historically, fires in these types 

were probably not only rare but quite variable in frequency 

and severity. We presume that fire-return intervals were at 

least 50 years, because shorter return intervals would have 

eliminated the junipers (Burkhardt and Tisdale 1976).

The juniper types that have resulted from recent invasion 

are typically on deeper soils with more productive herbaceous layer and hence more fuels: the JUOC/PUTR2/

FEID-AGSP and JUOC/FEID-AGSP types. These sites 

historically had fires frequent enough to exclude junipers; 

mean fire return intervals may have been as low as 12 to 

15 years (Miller and Rose 1999). Reduction of fine fuels 

by juniper competition may have made the vegetation less 

able to carry fires today than before juniper invasion 

(Petersen 2004).

Shrublands

We can subdivide our shrublands into two groups based 

on their fuel characteristics and historical fire regimes: (1) 

those with relatively dense herbaceous understory and historically frequent fires and (2) those with light fuels and rare 

fires. The former group includes most of our bitterbrush and 

big sagebrush plant associations. Historical fire return intervals as low as 12 to 15 years have been estimated for mountain big sagebrush steppe (Miller and Rose 1999). Given the 

rate of sagebrush regeneration, this fire frequency would 
7

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

have resulted in widespread grassland communities with 

little sagebrush. A longer fire return interval of 20 to 70 

years has also been suggested for sagebrush steppe (Brown 

and Smith 2000).

The second group includes all plant associations in the 

mountain mahogany (CELE3), stiff sagebrush (ARRI2), 

and low sagebrush (ARAR8) series, plus PUTR2/ERDO, 

ARTRV/AGSP-POSA12, and ARTR4/POSA12-DAUN. 

Fires were historically (and remain today) infrequent and 

patchy in these communities because the poor soils produce 

little fuel.

Mountain mahogany, sagebrush, and bitterbrush are 

readily killed by fire, although in some environments bitterbrush shows limited ability to resprout (Clark et al. 1982, 

Driscoll 1963) and mature mountain mahogany can survive 

some light fires (Arno and Wilson 1986). All three species recolonize burned areas by seed, generally seed carried from surviving plants by wind (mountain mahogany 

and sagebrush) or by animals (bitterbrush). Thus the rate of 

shrub recolonization depends on the size and severity of the 

burn, and weather for seed production and seedling survival in postfire years. Our monitoring of big sagebrush communities after fire shows that under good conditions, this 

shrub can reestablish 10 percent canopy cover as early as 10 

years after complete kill by fire. Our limited observations 

of bitterbrush and mountain mahogany suggest much slower 

recovery of these species.

Response of the herbaceous layer of shrublands to fire is 

like that of grasslands described below, with one important 

exception. When the shrub canopy is very dense, e.g., in big 

sagebrush with canopy cover of 50 percent or more, fires can 

burn very hot and cause more death of herbaceous plants 

than would otherwise occur. We have observed Idaho fescue 

eliminated from a site by severe fire in dense sagebrush, creating openings for weedier grass and forb species to expand.

Grasslands

Historical fire frequencies in grasslands of the study area remain largely unknown. There is consensus that fires were 

frequent (return intervals less than 35 years) and consumed 

most aboveground plant parts (Brown and Smith 2000). Our 

observations of modern fires show that patchy and light fires 

are not unusual in grasslands, especially on low-biomass 

types.

Plant associations of the Idaho fescue series contain 

enough biomass to burn nearly every year, but actual fires 

were not nearly this frequent because of low flammability 

of the vegetation early in the season and lack of ignitions 

(Agee 1996). Our monitoring shows that Idaho fescue is 

often suppressed for a few years after the fire, after which 

Figure 2—Generalized state-and-transition diagram used in this study. Boxes symbolize phases and arrows are transitions between them. The A, B, 

and C phases result from increasing grazing-related degradation that is probably reversible by natural succession. The D phases are in a second “state” 

separated from the first state by an ecologic threshold. Transitions to D phases are caused by loss of native species, invasion of exotic species, and soil 

erosion; they are probably not reversible by natural succession.

A1 B

A2

C1

C2

C3, etc.

D1

D2

D3, etc.

5 4 1, 2 5

5

1

State 1 State 2

Transitions:

(1) Heavy grazing and trampling

(2) Exotic species invasion

(3) Soil erosion

(4) Fire

(5) Succession

Threshold

1, 2, 3
8

GENERAL TECHNICAL REPORT PNW-GTR-641

it regains its former cover; other species in Idaho fescue 

communities return to prefire cover in the first postfire 

season. There is a flush of annual plants on some sites in 

the first year after fire, but annuals subsequently decline 

to prefire levels.

Response of bluebunch wheatgrass series vegetation to 

fire is even weaker, with plants typically regaining their 

prefire covers in postfire year 1. Occasionally bluebunch 

wheatgrass is suppressed a little and Sandberg’s bluegrass 

or annual forbs increase after fire, but effects are subtle and 

transient.

Some grassland types on very poor soils (AGSP-ERUM, 

AGSP-CYTEF, ERDO-POSA12, DAUN-LOLE2, and 

POSA12-DAUN) produce little biomass and probably had 

less continuous and less frequent fires than the other grassland types. Our limited monitoring suggests that, as in the 

case of the other grassland types, post- and prefire vegetation are very similar.

The Spread or Decline of Woody Plants

As mentioned above, juniper has become more widespread 

than it was in the past. Juniper expansion in our area began in the late 1800s and continues today (Miller and Rose 

1999). The main causes of juniper expansion are exclusion 

of fire, introduction of domestic livestock (which reduces fuels for fires and reduces vegetation that competes with juniper), and possibly an unusually moist climate during some 

recent decades. Burkhardt and Tisdale (1969) believe that 

juniper could potentially colonize any site that currently 

supports big sagebrush and Idaho fescue. Competition by junipers usually causes thinning of understory vegetation, especially shrubs (Miller et al. 2000). This effect has been 

linked to increased soil erosion in ecosystems invaded by 

junipers (Petersen 2004). As mentioned above, our JUOC/

PUTR2/FEID-AGSP and JUOC/FEID-AGSP types have resulted from juniper invasion. The presence of a few seedling 

junipers in several of our big sagebrush types (ARTRV/

AGSP-POSA12, ARTRV/FEID-AGSP, and ARTRV/FEIDKOCR) suggests that local juniper invasion of these types 

is likely in the future.

Big sagebrush is widely believed to be denser today than it 

was prior to settlement by Europeans. Likely reasons for this 

increase include fire suppression and removal of grass competition by livestock grazing. Controversy over this issue 

has been heated (see, e.g., Welch and Criddle 2003). There 

is little information about presettlement sagebrush densities; 

however, one study of old photographs in Wyoming and Idaho showed changes since the 1870s in sagebrush abundance 

to be variable and localized (Johnson 1986). Owing to the 

lower fire frequency today than in the past, there is probably 

proportionally less area of low-density, postfire regenerating 

sagebrush communities in our study area today than there 

was historically.

Some woody species of bunchgrass ecosystems have experienced declines owing to browsing by wildlife and livestock, notably bitterbrush (Purshia tridentata) and mountain 

mahogany (Cercocarpus ledifolius). Seedlings of these species are quite rare in our study area, and existing plants 

are often old and severely hedged, or (in the case of mountain mahogany) defoliated up to the height that animals can 

reach. These species are long lived and quite tolerant of defoliation once they are established (Garrison 1953), but recruitment of new plants is needed because productivity of 

individual plants drops off (after about 80 years in the case 

of bitterbrush) and older plants gradually die off (McConnell and Smith 1977). At least a temporary reduction in densities of all the large ungulates that feed on them—livestock, 

deer, and elk—will probably be needed at some point to ensure the survival of the next generation of these plants.

Newcomers to Bunchgrass Communities

Bunchgrass plant communities in the Western United States 

have undergone major changes as a result of the introduction 

of plants from Eurasia. These newcomers are mostly annuals that colonize disturbed soil. Among the most important 

are the annual bromegrasses, including cheatgrass (Bromus 

tectorum) and several other species (B. japonicus, B. mollis, 

B. brizaeformis, and B. commutatus). These grasses were introduced in the late 1800s, and by about 1930 had colonized 

most of the Pacific Northwest and intermountain region 

(Mack 1981). They are cool-season grasses with a winterannual life cycle: seeds germinate in the fall and grow until 

forced into dormancy by cold weather, then resume growth 

in the spring, flower, and produce seed before dying in early 

to mid summer (Klemmedson and Smith 1964). Cheatgrass 

and its relatives have displaced native annual grasses such as 

the annual fescues, as well as bluebunch wheatgrass, which 

was more successful at colonizing disturbed soil without 

such a strong competitor as cheatgrass (Mack 1981).

Cheatgrass is highly palatable to livestock when green 

and can be kept in check to some degree by spring grazing 

(Daubenmire 1940). Unfortunately, heavy spring and early 

summer grazing will also weaken native perennial bunchgrasses, and if grazing pressure is subsequently decreased, 

cheatgrass will outcompete the native grasses to fill any new 

gaps.

Cheatgrass is known to invade sagebrush communities 

and increase fuels and fire frequency, resulting in annual 

grasslands that are perpetuated by fire (Young and Evans 

1978). We have not observed this cheatgrass-fire cycle in 

our study area. Flushes of annual plants (including annual 

bromes like cheatgrass) sometimes occur in the first year 
9

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

after fires in our bunchgrass communities, but our observations to date show cover by annuals declining back to prefire 

levels within a year or two after the initial postfire flush 

without greatly altering the fire regime. Our densest stands 

of annual bromes occur in communities of the bluebunch 

wheatgrass and Idaho fescue series that have been highly 

disturbed by grazing and trampling, or in a few cases, by 

tillage on abandoned farm fields.

Another aggressive introduced annual grass has appeared 

in bunchgrass communities of our area, Ventenata dubia. 

We have even observed it to displace cheatgrass on some of 

our plots. Ventenata forms a dense thatch that probably inhibits reestablishment of native bunchgrasses. It is short, 

wiry, and unpalatable to livestock. Ventenata appears to be 

spreading in our area, and the limits to conditions it can tolerate are still unknown.

Medusahead (Elymus caput-medusae) is another invasive annual grass that has infested large areas in the Pacific 

Northwest but occurs only in a few places in our study area. 

Medusahead expansion here remains a possibility, at least 

locally on the disturbed, clay-rich soils that it prefers (Dahl 

and Tisdale 1975).

Many introduced perennial grasses are also present in our 

study area, some that were seeded onto burned areas or degraded rangeland, and some that have spread on their own. 

The only one that occurs widely in bunchgrass communities in our study area is Kentucky bluegrass (Poa pratensis). 

This grass is occasionally present in the more mesic bunchgrass plant associations, i.e., those containing Idaho fescue. This grass is highly tolerant of close grazing and can 

invade overgrazed sites if sufficient soil moisture is present 

(Daubenmire 1972, Mack and Thompson 1982). Intermediate or pubescent wheatgrass (Agropyron intermedium) is 

also present at scattered locations in mesic bunchgrass communities, but it does not appear to have spread far beyond 

where it was originally seeded.

Indicator Species

The habitat needs of plant species are evident by the 

environments in which they persist. Some species require 

stable conditions, others thrive on recurring instability. 

Some species have adapted to a particular locale owing 

to long-term climatic conditions of the area; others have 

colonized and thrived owing to changes in the microclimate of a particular site.

Plants that designate thresholds of environmental changes 

along gradients are called indicator plants. The indicator 

plants selected to define the plant community type or the 

plant association are those deemed to be the most diagnostic 

of a particular environment, i.e., those that have a high 

fidelity and constancy to the type. Although they do not 

necessarily indicate the sum of all environmental conditions, they are considered the best candidates of the associated flora within a classified type to indicate the occurrence 

and distribution of that vegetation unit.

The indicator species selected are those sought by field investigators to help determine proper assignment to a given 

plant association or plant community type. These indicator 

plants appear in the keys and in the names of the plant associations and community types. Information on identification 

of these plants may be found in Johnson (1998a).

Sampling and Field Methods

Sampling of bunchgrass plots used in this study began in 

1956 by Fred Hall (Hall 1973) and continued with the senior 

author’s fieldwork from the 1980s until 2004. Beginning in 

1993, the rangelands of the Blue Mountains were systematically covered to more adequately sample vegetation of varying types and conditions. In 1999 and 2000, this study was 

extended to include vegetation in the Ochoco Mountains. To 

assist in interpreting changes over time (trend), many Parker Three-Step Condition and Trend (Parker 1951) sites were 

used for plot locations. A total of 487 plots were sampled.

At each sample site a 375-m2 (72 ft in diameter) circular reconnaissance plot was established. Within this area, a 

total plant species list was derived. Next the canopy coverage was estimated to the nearest 5 percent for all species on 

the list. Additionally ground surface cover was estimated for 

bare ground, bedrock, rock, gravel, erosion pavement, mosses, lichens, and litter. Site environmental attributes were examined and noted as well. These included elevation (feet), 

aspect (degrees), slope (percent), lithology, soil depth, position, and slope shape.

Photopoints were established at each plot by locating a 

steel angle iron stake at the plot center. From this location, 

varying views were taken by using 35mm single lens reflex cameras employing color slide film and black and white 

print film.

The plots were intended for repeated monitoring. Therefore, reference markers and information necessary for relocation are provided for each sample location. Plot locations 

were described on plot cards and marked on U.S. Geological 

Survey quadrangle maps. Reference signs placed at the site 

and on adjacent points of access lead the investigator to the 

plot center stake. In the office, the plot locations were digitized from the topographic maps and the resulting coordinates stored in the plot database and geographic information 

system.
10

GENERAL TECHNICAL REPORT PNW-GTR-641

Plot sizea

Canopy 375 m2 1/10 acre

cover (%) xb r

c x r

 1 1.94 m (6.36 ft) 1.09 m (3.58 ft) 6.6 ft (2.01 m) 3.72 ft (1.13 m)

 5 4.33 m (14.20 ft) 2.44 m (8 ft) 14.76 ft (4.5 m) 8.33 ft (2.54 m)

 10 6.12 m (20.07 ft) 3.45 m (11.32 ft) 20.87 ft (6.37 m) 11.78 ft (3.59 m)

a Radius of 375 m2 circular plot is 10.93 m (35.85 ft); radius of 1/10-acre circular plot is 11.32 m (37.24 ft).

b x is the dimension of one side of a square equal to the coverage in percent.

c

 r is the radius of a circular area equal to the coverage in percent.

Classification and Data Analysis Methods

The present study is a refinement of previous studies (Hall 

1973, Johnson and Clausnitzer 1992, Johnson and Simon 

1987). We incorporated most of the plots used in Hall (1973) 

and Johnson and Clausnitzer (1992); addition of new data 

allowed us to more than double the previous sample size. 

Thirty-seven types defined by the previous publications 

adequately represented plots from this study and were incorporated unchanged, except that we describe them here by 

using more data or data specific to this study area. The other 

33 types are new and represent either subdivisions of types 

that were overly broad in Johnson and Clausnitzer (1992) 

(the FEID-AGSP, AGSP-POSA12, and POSA12-DAUN 

types) or communities that had not been encountered previously. We used multivariate statistical techniques (nonmetric 

multidimensional scaling, cluster analysis, and TWINSPAN; 

McCune and Grace 2002) to explore subdivision of previous 

broad types. The groups produced by these objective techniques were controlled by abundant species that had little indicator value (e.g., cheatgrass), and tended to group together 

plots with disturbed vegetation from a wide variety of environmental conditions. Thus, we found it more useful to define new types subjectively by using species with known 

environmental requirements as indicators. Knowledge of the 

indicator species was derived from the senior author’s field 

experience and Johnson and Simon (1987). Association tables were constructed by using tentative indicator plants; the 

proposed new types were examined for floristic homogeneity, similarity in site conditions (soils and setting), and similarity in response to disturbance. The choice of indicator 

species and their order in the key was then adjusted to produce types that better met these three criteria; this process 

was continued iteratively until the resulting types met the 

criteria to the authors’ satisfaction.

After a plant association was defined, it was further subdivided into phases by a similar process: subjective iterative 

refinement of association tables. We preferred this to multivariate methods both because of the small sample sizes involved and because we could define the phases based on 

species with a known response to the transition factors involved. For example, because large native bunchgrasses decrease with grazing pressure, we emphasized the sum cover 

of these grasses in defining many of the phases.

Use of the Management Guide

This management guide is organized with dichotomous keys 

and vegetation type descriptions for the determination of a 

plant association or a plant community type in the field.

Cover Percentages

The keys employ foliar cover percentages. This requires the 

user to accurately estimate the percentage of cover of a particular plant species in a fixed area, or plot. Indicator plant 

species are used as the best community representatives of 

the environment within the community. It is therefore critical that the investigator knows the flora and is able to estimate foliar cover.

Trees and shrub indicator plants are generally used to indicate their respective types if present at 10 percent or more 

cover. Most grass, sedge, rush, and forb indicators are used 

if present at 5 percent cover or more. Some indicator plants 

are extremely sensitive representatives of their environment 

and are used at cover as low as 1 percent.

Estimating Cover

The table below is provided to help the field investigator in 

making ocular estimates of abundance (crown canopy cover) 

of indicator plants for use in determining the proper vegetation type using the keys.
11

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Format of the Vegetation Type Descriptions

Headings—

Plant associations and plant community types are named 

by using the dominant species of the PNV followed by the 

subordinate indicator species of a different life form. An example is “mountain big sagebrush/Idaho fescue-bluebunch 

wheatgrass.” The life forms of different “layers” are separated by a slash (/). In this example, the sagebrush (a shrub) 

is differentiated from the fescue-bunchgrass (herb). When 

plants are used to name a vegetation type from the same layer and life form, a hyphen (-) is employed. In the example, 

the two bunchgrasses are separated by a hyphen as they are 

both herbs.

The names of the vegetation types are provided in three 

formats:

• Common names (mountain big sagebrush/Idaho 

fescue-bluebunch wheatgrass)

• Scientific names (Artemisia tridentata spp. vaseyana/

Festuca idahoensis-Agropyron spicatum)

• Database codes (ARTRV/FEID-AGSP)

All scientific names follow Hitchcock and Cronquist 

(1973). All computer codes follow the PLANTS National 

Database (USDA NRCS 2004b). All plant species encountered in the study are listed in appendixes A and B with scientific name, common name, PLANTS database code, and 

the former code from USDA Forest Service Region 6.

Photos—

A representative image of the plant community was selected for most major vegetation types. The reference pole 

used is 1 m tall and segmented into decimeters to assist in 

visualizing the size of the vegetation.

Distribution—

The range of the vegetation type in the Blue and Ochoco 

Mountains.

Environmental features—

The elevation range, slope percentage, aspect, slope shape, 

slope orientation, and rock type from sampled plots.

Soils—

A brief description of the soils from sampled plots.

Vegetation composition—

A description of the vegetation based on principal plant 

species found and the percentage composition of those 

plants from sampled plots.

States and transitions—

A listing of the phases and states derived from the classification process.

Management considerations—

Provides the species response to major disturbance activities (grazing, browsing, fire).

Relationship to other studies—

The relationship of this vegetation type to other similar 

classified vegetation types published in the Pacific Northwest.

Table of principal species—

A table containing a species list selected from the complete list of species found for a vegetation type. Only the 

primary species necessary for the description and the keys 

are listed. Mean cover values in percentages and the range 

of cover values in percentages are provided for the selected 

species. Mean cover was computed only for the plots where 

the plant was present. Constancy is the percentage of plots 

on which the species was found.

Table of ground surface features—

Mean percentage of cover and the range of cover values 

are provided for the ground surface features beneath the 

higher plants. Bare ground, bedrock, rock, gravel, erosion 

pavement, mosses and lichens, and litter are the ground surface features.

Table of environmental features—

Sample size (e.g., n = 10), means, and ranges are given 

for elevation, aspect, slope, and soils from sampled plots. 

Geologic information, slope position, and microrelief are 

summarized. In shrub/grass and grassland communities, 

herbage productivity is often provided. Soil available water 

capacity is computed for the upper 40 in of soil.
12

GENERAL TECHNICAL REPORT PNW-GTR-641

Keys for Determining the Bunchgrass Plant Associations and Plant Community Types

The keys that follow were derived to assist in determining 

the plant association or plant community type that best fits 

a particular site.

Limitations in the Use of the Keys

1. The keys are based on 490 sampled plots located in the 

Blue and Ochoco Mountains. This large geographic 

area contains a wide range of plant communities and 

environments. Not all the environmental variation was 

sampled. Therefore, the classification may not describe 

the vegetation occurring on some sites.

2. The natural stands have been, and some continue to be, 

highly modified. Sites exhibiting severe disturbances 

have been incorporated into this study. However, the 

keys are based mainly on less disturbed vegetation 

exemplified by phases A and B rather than C and D. 

Highly disturbed communities where introduced 

species have replaced the native species may be 

difficult to classify.

Rules for Use of the Keys

1. Select portions of stands demonstrating stability. On 

sites where disturbances have been severe resulting 

in vegetation of exotic species or earlier seral stages 

(phases C and D), try to select an adjacent, less disturbed area with the same soil and site conditions 

for determining the proper plant association or plant 

community type.

2. First use the “Key to Series” to determine the series 

and proceed to the proper key. Then choose the correct alternative by comparing choices 1a and 1b and 

follow the correct lead. For example, if a shrub community lacks mountain mahogany, 1b is chosen and 

the user is directed to lead 5. Proceed down through 

the key until the kind of vegetation encountered on 

the site is reached. Then turn to the page number provided and review the type description to verify the 

accuracy of the identification.

Key to Series

1a. Trees present with cover equal to or exceeding 10 percent ............................................................................. 2

1b. Trees absent or present with cover less than 10 percent .................................................................................. 4

2a. Ponderosa pine (PIPO) present and reproducing with 

total cover equal to or exceeding 10 percent ............................ See ponderosa pine series key, p. 13 

2b. Ponderosa pine absent or present with cover less than 10 percent ........................................................ 3

3a. Western juniper (JUOC) present and reproducing 

with total cover equal to or exceeding 10 percent .......................... See western juniper series key, p. 13

3b. Western juniper absent or present with cover less than 10 percent ............................................................... 4

4a. Shrubs present with cover equal to or exceeding 10 percent .......... See shrubland series key, p. 14

4b. Shrubs absent or present with cover less than 10 percent ................. See grassland series key, p. 16
13

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Key to Ponderosa Pine Series Vegetation

Ponderosa pine (PIPO) must be present and successfully reproducing; total cover must equal or exceed 

10 percent.

1a. Squaw apple (PERA4) present with cover equal to or exceeding 10 percent ...........PIPO/PERA4, p. 29

1b. Squaw apple absent or with cover less than 10 percent ................................................................................... 2

2a. Mountain mahogany (CELE3) present with cover equal to or exceeding 10 percent ........................ 3

3a. Mountain snowberry (SYOR2) associated with 

western juniper (JUOC) .......................................................PIPO-JUOC/CELE3-SYOR2, p. 29

3b. Mountain snowberry absent or with cover less than 10 percent .................................................... 4

4a. Idaho fescue and bluebunch wheatgrass present 

with cover equal to or exceeding 5 percent ................... PIPO/CELE3/FEID-AGSP, p. 18

4b. Wheeler’s bluegrass (PONEW) present with 

cover equal to or exceeding 5 percent ................................... PIPO/CELE3/PONEW, p. 20

2b. Mountain mahogany absent or with cover less than 10 percent ............................................................. 5

5a. Bitterbrush (PUTR2) present with cover equal to or exceeding 5 percent .................................................. 6

6a. Idaho fescue and bluebunch wheatgrass present with 

cover equal to or exceeding 5 percent ............................................ PIPO/PUTR2/FEID-AGSP, p. 21

6b. Bluebunch wheatgrass cover greater than 5 percent; 

Idaho fescue absent or with cover less than 5 percent ...........PIPO/PUTR2/AGSP-POSA12, p. 22

5b. Bitterbrush absent or with cover less than 5 percent ....................................................................................... 7

7a. Mountain big sagebrush (ARTRV) present with cover 

equal to or exceeding 10 percent .................................................... PIPO/ARTRV/FEID-AGSP, p. 24

7b. Mountain big sagebrush absent or with cover less than 10 percent ....................................................... 8

8a. Idaho fescue (FEID) present with cover equal to or exceeding 10 percent .................. PIPO/FEID, p. 26 

8b. Idaho fescue absent or with cover less than 10 percent ................................................... PIPO/AGSP, p. 28

Key to Western Juniper Series Vegetation

Western juniper (JUOC) must be present with cover equal to or exceeding 10 percent.

1a. Mountain mahogany (CELE3) present with cover equal to 

or exceeding 10 percent ........................................................................... JUOC/CELE3/FEID-AGSP, p. 30

1b. Mountain mahogany absent or with cover less than 10 percent ..................................................................... 2

2a. Bitterbrush (PUTR2) present with cover equal to 

or exceeding 10 percent ................................................................... JUOC/PUTR2/FEID-AGSP, p. 32

2b. Bitterbrush absent or with cover less than 10 percent ............................................................................. 3

3a. Low sagebrush (ARAR8) present with cover equal to or exceeding 

5 percent ................................................................................................................. JUOC/ARAR8/FEID, p. 34

3b. Low sagebrush absent or with cover less than 5 percent ................................................................................. 4

4a. Stiff sagebrush (ARRI2) present with cover equal to or exceeding 

5 percent ....................................................................................................................... JUOC/ARRI2, p. 36

4b. Stiff sagebrush absent or with cover less than 5 percent ......................................................................... 5

5a. Idaho fescue (FEID) present with cover equal to or exceeding 5 percent ..... JUOC/FEID-AGSP, p. 35

5b. Idaho fescue absent or with cover less than 5 percent .................................................... JUOC/AGSP, p. 36
14

GENERAL TECHNICAL REPORT PNW-GTR-641

Key to Shrubland Vegetation

Shrub cover by diagnostic species must equal or exceed 10 percent.

1a. Mountain mahogany (CELE3) present with cover equal to or exceeding 10 percent ................................ 2

2a. Idaho fescue (FEID) present with cover equal to or exceeding 

5 percent ........................................................................................................... CELE3/FEID-AGSP, p. 37

2b. Idaho fescue absent or with cover less than 5 percent ............................................................................. 3

3a. Bluebunch wheatgrass (AGSP) present with cover equal to or exceeding 5 percent ................. 4

4a. Bitterbrush (PUTR2) present with cover equal to or 

exceeding 10 percent .................................................................. CELE3-PUTR2/AGSP, p. 38

4b. Bitterbrush absent or with cover less than 10 percent .......................... CELE3/AGSP, p. 38

3b. Bluebunch wheatgrass absent or with cover less than 5 percent .......... CELE3/PONEW, p. 39

1b. Mountain mahogany absent or with cover less than 10 percent ..................................................................... 5

5a. Mountain snowberry (SYOR2) present on mounds with cover equal to or 

exceeding 10 percent; Mountain big sagebrush absent .................................................... SYOR2, p. 57

5b. Mountain snowberry absent or with cover less than 10 percent ............................................................ 6

6a. Bitterbrush (PUTR2) present with cover equal to or exceeding 10 percent ................................................ 7

7a. Mountain big sagebrush (ARTRV) present with cover equal to or exceeding 10 percent ................ 8

8a. Idaho fescue (FEID) cover greater than 5 percent; 

bluebunch wheatgrass (AGSP) absent ............................................ PUTR2-ARTRV/FEID, p. 42

8b. Bluebunch wheatgrass codominant with Idaho fescue .. PUTR2-ARTRV/FEID-AGSP, p. 39

7b. Mountain big sagebrush absent or with cover less than 10 percent ............................................................... 9

9a. Idaho fescue (FEID) and bluebunch wheatgrass (AGSP) 

cover greater than 5 percent ................................................................. PUTR2/FEID-AGSP, p. 41

9b. Idaho fescue and bluebunch wheatgrass cover less than 5 percent .......... PUTR2/ERDO, p. 42

6b. Bitterbrush absent or with cover less than 10 percent ................................................................................... 10

10a. Mountain big sagebrush (ARTRV) present with cover equal to or exceeding 5 percent ............... 11

11a. Mountain snowberry (SYOR2) present with cover equal to or exceeding 10 percent ............ 12

12a. Mountain brome (BRCA5) present with cover 

 equal to or exceeding 5 percent .......................................... ARTRV-SYOR2/BRCA5, p. 48

12b. Mountain brome absent or with cover less than 5 percent ............. ARTRV-SYOR2, p. 48

11b. Mountain snowberry absent or with cover less than 5 percent ................................................... 13

13a. Mountain brome (BRCA5) present with cover equal to 

 or exceeding 5 percent .......................................................................... ARTRV/BRCA5, p. 49

13b. Mountain brome absent or with cover less than 5 percent ................................................... 14
15

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

14a. Squaw apple (PERA4) present with cover greater than 10 percent ...... ARTRV-PERA4, p. 49

14b. Squaw apple absent or with cover less than 10 percent ................................................................ 15

15a. Giant wild rye (ELCI2) present with cover greater than 

 5 percent ................................................................................................... ARTRV/ELCI2, p. 49

15b. Giant wild rye absent or with cover less than 10 percent ..................................................... 16

16a. Prairie junegrass (KOCR) present with cover equal to or 

 exceeding 5 percent ........................................................................... ARTRV/FEID-KOCR, p. 43

16b. Prairie junegrass absent or with cover less than 5 percent ........................................................... 17

17a. Idaho fescue (FEID) present with cover equal to or 

 exceeding 5 percent ..................................................................... ARTRV/FEID-AGSP, p. 45

17b. Idaho fescue absent or with cover less than 5 percent ...... ARTRV/AGSP-POSA12, p. 47

10b. Mountain big sagebrush absent or with cover less than 5 percent ...................................................... 18

18a. Low sagebrush (ARAR8) present with cover equal to or exceeding 10 percent ..................................... 19

19a. Idaho fescue (FEID) present with cover equal to or exceeding 

 5 percent ........................................................................................................ ARAR8/FEID-AGSP, p. 50

19b. Idaho fescue absent or with cover less than 5 percent .......................................................................... 20

20a. Bluebunch wheatgrass (AGSP) present with cover equal to or 

 exceeding 5 percent .......................................................................................... ARAR8/AGSP, p. 52

20b. Bluebunch wheatgrass absent or with cover less than 5 percent ........ ARAR8/POSA12, p. 54

18b. Low sagebrush absent or with cover less than 10 percent ............................................................................ 21

21a. Stiff sagebrush (ARRI2) present with cover equal to or exceeding 10 percent ............................... 22

22a. Sandberg’s bluegrass (POSA12) present with cover equal to or 

 exceeding 5 percent ...................................................................................... ARRI2/POSA12, p. 55

22b. Sandberg’s bluegrass absent or with cover less than 5 percent ................ ARRI2/PEGA, p. 57

21b. Stiff sagebrush absent or with cover less than 10 percent .................................................................... 23

23a. Threetip sagebrush (ARTR4) present with cover equal to or greater 

 than 10 percent .............................................................................................. ARTR4/POSA12-DAUN, p. 57

23b. Creeping Oregon-grape (BERE) present with cover equal to or 

 exceeding 10 percent ........................................................................................... BERE/AGSP-APAN2, p. 57
16

GENERAL TECHNICAL REPORT PNW-GTR-641

Key to Grassland Vegetation

Trees and shrubs are absent or their cover is less than 10 percent.

1a. Grasslands above 6,000 ft in elevation (subalpine grasslands) ...................................................................... 2

1b. Grasslands below 6,000 ft in elevation ............................................................................................................ 13

2a. Green fescue (FEVI) present with cover equal to or exceeding 5 percent ........................................... 3

3a. Parry’s rush (JUPA) present with cover equal to or exceeding 5 percent ..... FEVI-JUPA, p. 58

3b. Parry’s rush absent or with cover less than 5 percent ....................................................................... 4

4a. Lupines (LUPIN) present with cover equal to or exceeding 10 percent ........... FEVI-LULA3, p. 58

4b. Lupines absent or cover is less than 10 percent ......................................................................................... 5

5a. Penstemons (PENST) present with cover equal to or exceeding 

10 percent .............................................................................................................. FEVI-PENST, p. 58

5b. Penstemons absent or cover is less than 10 percent .......................................................................... 6

2b. Green fescue absent or with cover less than 5 percent ............................................................................ 7

7a. Idaho fescue (FEID) present with cover equal to or exceeding 5 percent .................................... 8

8a. Red avens (GETR) present with cover equal to or exceeding 

5 percent ......................................................................................................... FEID-GETR, p. 58

8b. Red avens absent or with cover less than 5 percent ................................................................. 9

9a. Cymopterus (CYTEF) present with cover equal to or 

exceeding 1 percent ...................................................................... FEID-AGSP-CYTEF, p. 59

9b. Cymopterus absent ....................................................................................................................... 10

10a. Cusick’s frasera (FRALC2) present with cover 

 equal to or exceeding 3 percent ..................................... FEID-AGSP-FRALC2, p. 60

10b. Cusick’s frasera absent or cover is less than 3 percent ................................................. 11

7b. Idaho fescue absent or relict (less than 5 percent) .......................................................................... 11

11a. Oniongrass (MEBU) present at cover of 5 percent or greater ......... MEBU-STOC2, p. 61

11b. Oniongrass absent or cover less than 5 percent; western 

 needlegrass (STOC2) present at a cover of 5 percent or greater .............................................

........................................................................................................ STOC2-SIHY (Alpine), p. 61

12a. Idaho fescue (FEID) present at cover of 5 percent or greater ...................................................................... 13

12b. Idaho fescue absent or with cover less than 5 percent .................................................................................. 19

13a. Prairie junegrass (KOCR) present at cover of 1 percent or 

greater on mounds ......................................................................................... FEID-KOCR (Mound), p. 

62

13b. Prairie junegrass present (but not on mounds) ....................................................................................... 14

14a. Prairie junegrass present at cover of 5 percent or greater ............... FEID-KOCR (Ridge), p. 

64

14b. Prairie junegrass absent or with cover less than 5 percent ........................................................... 15

15a. Lupines (LUPIN) present at cover of 5 percent or greater ..................... FEID-AGSP-LUPIN, p. 66

15b. Lupines absent or with cover less than 5 percent .................................................................................. 16

16a. Arrowleaf balsamroot (BASA3) present with cover of 

5 percent or greater ................................................................................ FEID-AGSP-BASA3, p. 67

16b. Arrowleaf balsamroot absent or with cover less than 5 percent ................................................. 17

17a. Phloxes (PHLOX) present at cover of 5 percent or greater .................. FEID-AGSP-PHLOX, p. 69

17b. Phloxes absent or with cover less than 5 percent ................................................................................... 18
17

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

18a. Bluebunch wheatgrass (AGSP) present with cover greater than 

 5 percent ................................................................................................................. FEID-AGSP, p. 71

18b. Bluebunch wheatgrass cover less than 5 percent ........................................... FEID-DAUN, p. 72

19a. Bluebunch wheatgrass (AGSP) present at cover of 5 percent or greater ................................................... 20

19b. Bluebunch wheatgrass absent or with cover less than 5 percent ................................................................ 32

20a. Mountain brome (BRCA5) present with cover of 5 percent or greater ........... AGSP-BRCA5, p. 87

20b. Mountain brome absent or with cover of less than 5 percent .............................................................. 21

21a. Lupines (LUPIN) present with cover of 5 percent or greater ................... AGSP-POSA12-LUPIN, p. 73

21b. Lupines absent or with cover of less than 5 percent ...................................................................................... 22

22a. Arrowleaf balsamroot (BASA3) present with cover of 

 5 percent or greater .................................................................................. AGSP-POSA12-BASA3, p. 75

22b. Arrowleaf balsamroot absent or with cover less than 5 percent ......................................................... 23

23a. Creamy buckwheat (ERHE2) present with cover of 5 percent 

 or greater .......................................................................................................... AGSP-POSA12-ERHE2, p. 77

23b. Creamy buckwheat absent or with cover less than 5 percent ...................................................................... 24

24a. Blue Mountain milkvetch (ASRE5) present with cover of 

 5 percent or greater ................................................................................. AGSP-POSA12-ASRE5, p. 78

24b. Blue Mountain milkvetch absent or with cover less than 5 percent ................................................... 25

25a. Bighead clover (TRMA3) present with cover of 5 percent 

 or greater ......................................................................................................... AGSP-POSA12-TRMA3, p. 80

25b. Bighead clover absent or with cover less than 5 percent .............................................................................. 26

26a. Skullcap (SCAN3) present with cover of 5 percent or greater ........ AGSP-POSA12-SCAN3, p. 82

26b. Skullcap absent or with cover less than 5 percent ................................................................................. 27

27a. Dogbane (APAN2) present with cover of 5 percent or greater ................ AGSP-POSA12-APAN2, p. 83

27b. Dogbane absent or with cover less than 5 percent ........................................................................................ 28

28a. Onespike oatgrass (DAUN) present with cover of 5 percent 

 or greater ..................................................................................................... AGSP-POSA12-DAUN, p. 84

28b. Onespike oatgrass absent or with cover less than 5 percent ................................................................ 29

29a. Sandberg’s bluegrass (POSA12) present with cover of 5 percent or greater ........ AGSP-POSA12, p. 86

29b. Sandberg’s bluegrass absent or relict (cover less than 5 percent) ............................................................... 30

30a. Sulfur-flower buckwheat (ERUM) present with cover of 5 percent 

 or greater ..................................................................................................................... AGSP-ERUM, p. 88

30b. Sulfur-flower buckwheat absent or with cover of less than 5 percent ................................................ 31

31a. Cymopterus (CYTEF) present with cover of 5 percent or greater .......................... AGSP-CYTEF, p. 88

31b. Cymopterus absent or with cover of less than 5 percent .............................................................................. 32

32a. Douglas’ buckwheat (ERDO) present with cover of 5 percent or greater ... ERDO-POSA12, p. 88

32b. Douglas’ buckwheat absent or with cover of less than 5 percent ....................................................... 33

33a. Bulbous bluegrass (POBU) present with cluster tarweed ....................................... POBU-MAGL2, p. 88

33b. Bulbous bluegrass and/or tarweed absent or at cover of less than 5 percent ............................................ 34

34a. Slenderfruit lomatium (LOLE2) and rushes (JUNCUS) present 

 with onespike oatgrass dominant .......................................................................... DAUN-LOLE2, p. 89

34b. Slenderfruit lomatium and rushes absent; Sandberg’s 

 bluegrass dominant ................................................................................................ POSA12-DAUN, p. 91
18

GENERAL TECHNICAL REPORT PNW-GTR-641

Ponderosa Pine Series

Alkali Creek, Emigrant Creek RD, Malheur NF.

Distribution—

Central and southern Blue Mountains; Ochoco Mountains.

Environmental features—

This plant association was found on andesite, basalt, pumice, and tuff. Elevations ranged from 4,250 to 5,950 ft (mean 

4,900 ft). Slopes were moderately steep (mean 23 percent). 

Sample sites were on northerly and southerly aspects on convex and concave surfaces. Positions ranged from shoulders 

to backslopes to footslopes. Soils had a sandy loam or silt 

loam surface layer up to 12 in thick (sometimes absent) over 

very to extremely gravelly loamy soil, with bedrock at a 

depth of 1 to 2 ft. Soil pH was slightly acid, and available 

water capacity was low. One study profile had a silty clay 

loam subsoil over bedrock at 2 ft, and moderate available 

water capacity.

Vegetation composition—

This is the warmest and driest of the PIPO/CELE3 plant 

associations. The other PIPO/CELE3 plant associations are 

more mesic, with either elk sedge or Wheeler’s bluegrass 

associated. Ponderosa pine is always present in this association. Western juniper and Douglas-fir may occur as incidental trees. Mountain mahogany is the dominant shrub, 

with mountain big sagebrush and bitterbrush often associated. Grasses are the most abundant herbaceous plants. Idaho 

fescue and bluebunch wheatgrass codominate, with Sandberg’s bluegrass and bottlebrush squirreltail often present. 

Forb composition is usually weak with low coverages. Often present are yarrow, pale agoseris, arrowleaf balsamroot, 

creamy buckwheat, and phlox.

States and transitions—

Three phases were defined as follows:

A Idaho fescue is dominant over bluebunch wheatgrass. 

Disturbances have been either minimal or of short 

duration.

B Bluebunch wheatgrass has increased to codominance 

with Idaho fescue. Disturbances from severe burns, 

ungulate overuse, or climatic change promoting 

warmer, drier microsite conditions promote this stage.

C Bluebunch wheatgrass dominates over all other 

herbaceous plants. Continued site disturbances that 

are frequent or of long duration promote this phase.

Management considerations—

This type is highly valued as deer winter range. Moderate 

to severe burns kill mountain mahogany, and ungulate 

browsing of mountain mahogany may prevent regeneration. 

The bunchgrasses are promoted by light to moderate burns. 

Ponderosa pine/mountain mahogany/Idaho fescue-bluebunch wheatgrass plant association

Pinus ponderosa/Cercocarpus ledifolius/Festuca idahoensis-Agropyron spicatum

PIPO/CELE3/FEID-AGSP CPS234 N = 9

Ground surface features—

Phase

A B C A + B

(n = 5) (n = 2) (n = 2) range

Cover (%)

Bare ground 3 8 4 0–12

Bedrock 3 0 11 0–8

Rock 9 6 20 0–20

Gravel 0 7 0 0–14

Pavement 0 0 11 0

Mosses and lichens 10 9 2 0–11

Litter 75 70 52

 Mean Range

Elevation (feet) 4,900 4,250–5,950

Slope (percent) 23 18–50

Soil pH (n = 5) 6.2–6.8

Soil available water capacity 1.5–6 (low to moderate)

 (inches, n = 5)

Depth to bedrock (inches, n = 9) 12–25

Herbage (pounds/acre, n = 6) 428 303–740

Aspect (number of plots) NW (5), NE (0), SE (3), SW (1)

Lithology Andesite, basalt, pumice, tuff

Position Shoulder, backslope, footslope, 

 summit

Slope shape Convex, concave
19

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Overgrazing tends to promote creamy buckwheat, squirreltail, and annuals. An excellent 

community for visualizing the effects of ungulate use in this type may be found on the 

Emigrant Creek Ranger District (RD) above 

Devine Canyon at the Larsen Spring cattle exclosure (erected in 1963). Here deer use the 

bitterbrush inside the exclosure, while seedlings and saplings of mountain mahogany occur abundantly beside the older shrubs inside 

the exclosure. Few bitterbrush and mountain 

mahogany are present outside the exclosure, 

where domestic and wild ungulates browse 

them heavily.

Relationship to other studies—

This plant association was previously 

classified in the Blue and Ochoco Mountains 

(Johnson and Clausnitzer 1992).

Principal species—

Phase

A B C A + B

Species Code (n = 5) (n = 2) (n = 2) range

Cover (%)/constancy (%) Cover (%)

Trees:

 ponderosa pine PIPO 17/100 34/100 12/100 10–45

 Douglas–fir PSME 2/20 – 3/100 0–2

 western juniper JUOC 8/60 12/100 8/50 0–15

Shrubs:

 mountain mahogany CELE3 29/100 15/100 15/100 5–60

 mountain big sagebrush ARTRV 8/100 5/50 0 1–15

 bitterbrush PUTR2 3/60 6/100 1/50 0–8

 wax currant RICE 15/20 0 2/50 0–15

Grasses:

 Idaho fescue FEID 33/100 12/100 2/50 10–38

 bluebunch wheatgrass AGSP 7/100 10/100 25/100 4–15

 prairie junegrass KOCR 4/40 0 0 0–4

 Sandberg’s bluegrass POSA12 17/80 4/100 8/100 0–30

 bottlebrush squirreltail SIHY 2/80 0 0 0–5

Forbs:

 common yarrow ACMIL 2/60 1/100 2/100 0–2

 pale agoseris AGGL 2/60 0 0 0–3

 arrowleaf balsamroot BASA3 2/60 0 0 0–2

 hawksbeards CREPI 13/60 1/50 0 0–35

 creamy buckwheat ERHE2 2/65 1/100 1/50 0–3

 phloxes PHLOX 2/40 1/50 0 0–2
20

GENERAL TECHNICAL REPORT PNW-GTR-641

Ponderosa pine/mountain mahogany/Wheeler’s bluegrass plant association

Pinus ponderosa/Cercocarpus ledifolius/Poa nervosa var. wheeleri

PIPO/CELE3/PONEW CPS233 N = 7

Distribution—

Ochoco Mountains.

Environmental features—

This vegetation type is found on rhyolitic tuffs in the 

Ochoco Mountains. Elevations ranged from 5,125 to 

5,425 ft (mean 5,304 ft). Slopes were usually gentle 

(mean 5 percent). Sampled sites were on northerly and 

southerly slopes with either convex or straight shape. 

Slope positions were ridgetops or shoulders of ridges. 

Soils were shallow to moderately deep over rhyolite.

Emigrant Butte, Emigrant Creek RD, Malheur NF.

Principal species—

Phase

A B A + B

Species Code (n = 3) (n = 4) range

Cover (%)/constancy (%) Cover (%)

Trees:

 ponderosa pine PIPO 28/100 42/100 23–50

 western juniper JUOC 18/67 9/75 0–25

Shrubs:

 mountain mahogany CELE3 18/100 17/100 10–30

 bitterbrush PUTR2 12/100 6/100 1–25

Grasses and grasslikes:

 Wheeler’s bluegrass PONEW 15/100 10/100 8–15

 Idaho fescue FEID 2/67 2/50 0–2

 bottlebrush squirreltail SIHY 5/33 1/100 0–5

 western needlegrass STOC2 1/100 1/50 0–1

 Ross’ sedge CARO5 4/100 7/100 1–15

Forbs:

 Iomatiums LOMAT 1/100 1/50 0–1

 groundsels SENEC 3/100 2/100 1–6

 western hawkweed HIAL 2/67 1/25 0–2

Mean Range

Elevation (feet) 5,304 5,125–5,425

Slope (percent) 5 2–15

Herbage (pounds/acre, n = 7) 129 60–200

Aspect (number of plots) NW (3), NE (0), SE (2), SW (2)

Lithology Argillite

Position Shoulder, ridgetop

Slope shape Convex, linear/planar

Ground surface features—

Phase

A B A + B

(n = 3) (n = 4) range

Cover (%)

Bare ground 2 3 0–5

Bedrock 2 0 0–5

Rock 2 2 0–5

Gravel 0 0 0

Pavement 5 5 0–10

Mosses and lichens 1 1 0–5

Litter 88 89

Vegetation composition—

Western juniper is usually associated in a forest savannah growing above the mountain mahogany and bitterbrush 

shrubs. Grasses dominate over forbs, with Wheeler’s bluegrass 

the most prominent. Ross’ sedge was always found; Idaho 

fescue and western needlegrass were frequently present. Forb 

diversity and cover were low. Groundsels, hawkweeds, and 

lomatiums were the most frequent forbs.

States and transitions—

Two phases were defined as follows:

A Wheeler’s bluegrass cover is ≥15 percent. 

Disturbances minimal or of short duration.

B Wheeler’s bluegrass cover is <15 percent. 

Disturbances of moderate severity or duration.

Management considerations—

Moderate and severe burns may cause extensive mortality to 

both mountain mahogany and bitterbrush. Disturbances from 

domestic livestock and fires tend to promote juniper, bottlebrush 

squirreltail, western needlegrass, and yarrow. Intensive use may 

severely retard the recruitment of young mountain mahogany 

plants. This community is heavily used by wild ungulates in 

winter rangelands. Herbage production is extremely low (mean 

129 lb/ac). Bitterbrush and mountain mahogany provide key fall 

and winter browse.

Relationship to other studies—

This plant association was previously classified and described 

in the Ochoco Mountains (Johnson and Clausnitzer 1992).

Fred Hall
21

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Ponderosa pine/bitterbrush/Idaho fescue-bluebunch wheatgrass plant association

Pinus ponderosa/Purshia tridentata/Festuca idahoensis-Agropyron spicatum

PIPO/PUTR2/FEID-AGSP CPS226 N = 7

Powder River canyon, Baker RD, Wallowa-Whitman NF.

Distribution—

Central and southern Blue Mountains; Ochoco 

Mountains.

Environmental features—

This plant association was found on basalts and rhyolites. Elevations ranged from 4,000 to 5,260 ft (mean 

4,710 ft). Slopes were gentle to steep (mean 11 percent). 

Sampled sites were on northerly and southerly aspects on 

convex, straight, or undulating surfaces and on all slope 

positions. Soils had 6 to 16 in of loamy surface over very 

to extremely gravelly or cobbly subsoil. One profile had 

silty clay loam subsoil over weathered bedrock at 32 in. 

Soil available water capacity was low to moderate, and 

pH was nearly neutral except for some acid soil near 

the surface.

Vegetation composition—

Ponderosa pine forms an open forest over a shrub layer 

dominated by bitterbrush. Western juniper may be associated. 

Herbaceous vegetation is dominated by grasses. Idaho fescue is 

always present and usually abundant. Other grasses usually 

present at low coverages in these communities are bluebunch 

wheatgrass, Sandberg’s bluegrass, and bottlebrush squirreltail. 

Forbs occur at low coverages.

States and transitions—

Only one phase was defined where vegetation has been relatively undisturbed. More severe or frequent disturbances could 

provide additional phases where increases would occur by rabbitbrush, needlegrass, squirreltail, annual grasses, and yarrow.

Ground surface features—

Phase

A C A + B

(n = 5) (n = 2) range

Cover (%)

Bare ground 9 2 1–25

Bedrock 0 0 0

Rock 4 15 1–5

Gravel 1 1 0

Pavement 6 9 0

Mosses and lichens 5 4 0–5

Litter 75 69

Mean Range

Elevation (feet) 4,699 4,000–5,260

Slope (percent) 11 2–30

Soil pH (n = 2) 5.2–6.8

Soil available water capacity 3.5–8 (low to moderate)

 (inches, n = 2)

Depth to bedrock or extremely 6–32

 gravelly soil (inches, n = 5)

Herbage (pounds/acre, n = 4) 281 132–545

Aspect (number of plots) NW (1), NE (1), SE (0), SW (2)

Lithology Basalt, rhyolite

Position Ridgetops and all slope positions

Slope shape Convex, straight, undulating

Principal species—

Phase

A C A + B

Species Code (n = 5) (n = 2) range

Cover (%)/constancy (%) Cover (%)

Trees:

 ponderosa pine PIPO 19/100 21/100 5–41

 western juniper JUOC 18/40 41/100 0–25

Shrubs:

 bitterbrush PUTR2 14/100 0 5–25

 green rabbitbrush CHVI8 1/40 0 0–1

 creeping Oregon grape BERE 1/40 0 0–1

 mountain mahogany CELE3 6/40 0 0–10

Grasses:

 Idaho fescue FEID 29/100 20/100 20–40

 bluebunch wheatgrass AGSP 2/80 4/100 0–4

 prairie junegrass KOCR 2/60 0 0–5

 Sandberg’s bluegrass POSA12 4/80 2/100 0–10

 bottlebrush squirreltail SIHY 1/60 0 0–1

Forbs:

 common yarrow ACMIL 3/80 0 1–5

 basalt milkvetch ASFI 5/20 12/100 0–5

 twin arnica ARSO2 5/40 0 0–5

 western hawkweed HIAL 1/40 0 0–1

 western groundsel SEIN2 2/40 0 0–3
22

GENERAL TECHNICAL REPORT PNW-GTR-641

Ponderosa pine/bitterbrush/bluebunch wheatgrass-Sandberg’s bluegrass plant association

Pinus ponderosa/Purshia tridentata/Agropyron spicatum-Poa sandbergii

PIPO/PUTR2/AGSP-POSA12 CPS229 N = 3

Distribution—

Southern Blue Mountains; Ochoco Mountains.

Environmental features—

This plant association was found on basalt, volcanic tuff, 

and argillite. Elevations ranged from 4,700 to 5,210 ft (mean 

4,927 ft). Slopes were moderately steep (mean 32 percent). 

Sampled sites were on northerly and southerly aspects on 

convex and concave surfaces. All slope positions were represented. The one soil profile studied consisted of very to 

extremely gravelly sandy loam, with bedrock at a depth of 

16 in. Available water capacity was very low and pH nearly 

neutral.

Jackie Creek, Emigrant Creek RD, Malheur NF.

Ground surface features—

Phase

A B D A + B

(n = 1) (n = 1) (n = 1) range

Cover (%)

Bare ground 5 1 3 1–5

Bedrock 0 0 0 0

Rock 11 20 1 11–20

Gravel 0 40 3 0–40

Pavement 0 0 0 0

Mosses and lichens 1 0 0 0–1

Litter 83 39 90

Mean Range

Elevation (feet) 4,927 4,700–5,210

Slope (percent) 32 20–45

Herbage (pounds/acre, n = 2) 280 150–440

Aspect (number of plots) NW (0), NE (1), SE (1), SW (1)

Lithology Basalt, argillite, tuff

Position All slope positions

Slope shape Convex, concave

Management considerations—

These communities are a valuable part of deer winter 

range in the southern Blue and Ochoco Mountains. Bitterbrush is highly nutritious. Overbrowsing severely hedges 

bitterbrush shrubs, retards recruitment of juvenile bitterbrush seedlings, and imperils the future existence of 

bitterbrush. Light- to moderate-severity fires enhance 

ponderosa pine vitality. Bitterbrush will be retarded if fire 

occurs when soils are too dry. A good example of this plant 

association is found in the Sumpter Three-Way Exclosure 

at the west end of McEwan Valley on the Baker Ranger 

District of the Wallowa-Whitman NF.

Vegetation composition—

This is the warmest and driest of the PIPO/PUTR2 

plant associations. Ponderosa pine is always present and 

dominant over a shrub layer of bitterbrush. Western juniper is usually present. Grasses dominate the forbs in the 

herbaceous layer. Bluebunch wheatgrass, fleabanes, and 

yarrow are prominent.

Relationship to other studies—

This is a widespread plant association in the Pacific 

Northwest first classified by Daubenmire and Daubenmire 

(1968) in eastern Washington. It was subsequently described 

by Pfister et al. (1977) in Montana, Steele et al. (1981) in 

central Idaho, Clausnitzer and Zamora (1987) in northern 

Washington, Volland (1976) and Hopkins (1979a, 1979b) in 

central Oregon, and by Johnson and Clausnitzer (1992) in 

the Blue and Ochoco Mountains.
23

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

States and transitions—

Three phases were defined as follows:

A High cover of bitterbrush and bluebunch 

wheatgrass (both >15 percent).

B Bitterbrush cover is <15 percent.

C Bluebunch wheatgrass <5 percent or absent; 

bare ground is >10 percent.

Management considerations—

Bitterbrush is highly valued deer winter range in the 

southern Blue and Ochoco Mountains. Browsing can be 

severe and impede vitality of the plants. Fire can damage 

bitterbrush plants if a severe burn occurs when soils are 

Principal species—

Phase

A B D A + B

Species Code (n = 1) (n = 1) (n = 1) range

Cover (%) / constancy (%) Cover (%)

Trees:

 ponderosa pine PIPO 12/100 15/100 30/100 12–15

 western juniper JUOC 3/100 — 9/100 0–3

Shrubs:

 bitterbrush PUTR2 21/100 5/100 15/100 5–21

 creeping Oregon grape BERE 1/100 3/100 0 1–3

Grasses:

 bluebunch wheatgrass AGSP 31/100 10/100 0 10–31

 Sandberg’s bluegrass POSA12 1/100 1/100 5/100 1–1

Forbs:

 common yarrow ACMIL 2/100 0 1/100 0–2

 fleabanes ERIGE2 8/100 0 1/100 0–8

 tailcup lupine LUCA 0 0 10/100 0–1

 penstemons PENST 0 1/100 1/100 0–1

dry. Overgrazing in this driest of ponderosa pine/bitterbrush associations can eliminate bluebunch wheatgrass. 

Sandberg’s bluegrass, yarrow, lupines, and penstemons 

will increase with heavy grazing pressure.

Relationship to other studies—

This plant association was first described as an incidental community type in the Wallowa Mountains (Johnson 

and Simon 1987). It was then described as a plant association by Lillybridge et al. (1995) in the eastern Cascades of 

Washington. This is the first description of this plant association in the Blue and Ochoco Mountains.
24

GENERAL TECHNICAL REPORT PNW-GTR-641

Ponderosa pine/mountain big sagebrush/Idaho fescue-bluebunch wheatgrass plant association

Pinus ponderosa/Artemisia tridentata/Festuca idahoensis-Agropyron spicatum

PIPO/ARTRV/FEID-AGSP CPS131 N = 7

Distribution—

Southern Blue Mountains; Ochoco Mountains.

Environmental features—

This plant association was found on basalt, andesite, argillite, and dacite. Elevations ranged from 4,500 to 5,550 ft 

(mean 5,029 ft). Slopes were gentle to moderately steep (5 

to 40 percent). Sampled sites were on northerly and southerly aspects on convex and straight surfaces. Plots were on 

backslope and footslope locations.

Lonesome Exclosure, Gilbert Ridge, Emigrant Creek RD, Malheur NF.

Ground surface features—

Phase

A B C1 C2 A + B

(n = 2) (n = 3) (n = 1) (n = 1) range

Cover (%)

Bare ground 6 13 0 0 0–40

Bedrock 0 9 5 5 0–20

Rock 4 12 15 20 0–35

Gravel 0 1 0 0 0–3

Pavement 0 7 0 0 0–15

Mosses and lichens 4 1 0 0 0–8

Litter 86 57 80 75

Mean Range

Elevation (feet) 5,029 4,500–5,550

Slope (percent) 21 5–40

Herbage (pounds/acre, n = 4) 420 300–620

Aspect (number of plots) NW (0), NE (4), SE (0), SW (3)

Lithology Basalt, andesite, argillite, dacite, rhyolite

Position Backslope, footslope, summit

Slope shape Convex, straight

Vegetation composition—

These communities are a savannah with ponderosa pine 

cover of less than 20 percent; western juniper cover generally less than 10 percent; and a shrub layer dominated by 

sagebrush (generally about 25 percent cover). Bunchgrasses 

dominate the herbaceous layer. Idaho fescue and bluebunch 

wheatgrass codominate, with Sandberg’s bluegrass usually 

associated at lower cover levels. Forbs are few, with yarrow, 

creamy buckwheat, and narrowleaf pussytoes the most 

common.

States and transitions—

Four phases were defined as follows:

A Deep-rooted bunchgrasses (Idaho fescue and 

bluebunch wheatgrass) with combined cover 

≥25 percent. A balance between sagebrush and 

these bunchgrasses is maintained by periodic 

fire and light to moderate grazing pressure.

B Deep-rooted bunchgrasses with combined cover 

<25 percent. This represents an imbalance between 

sagebrush and the bunchgrasses owing to lack of 

fire or to overgrazing.

C1 Dominated by annual bromes (especially cheatgrass). 

A loss of dominance by Idaho fescue and bluebunch 

wheatgrass owing to severe overgrazing and ground 

disturbance.

C2 Dominated by bluegrasses (Poa sandbergii and 

Poa nervosa). Fescue and wheatgrass have lost 

dominance owing to soil compaction, soil loss, 

and overgrazing.
25

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Principal species—

Phase

A B C1 C2 A + B

Species Code (n = 2) (n = 3) (n = 1) (n = 1) range

Cover (%)/constancy (%) Cover (%)

Trees:

 ponderosa pine PIPO 23/100 10/100 18/100 1/100 5–23

 western juniper JUOC 1/50 7/67 13/100 15/100 0–8

Shrubs:

 mountain big sagebrush ARTRV 18/100 23/100 10/100 25/100 10–30

 creeping Oregon grape BERE 2/50 0 0 0 0–2

 mountain mahogany CELE3 1/50 0 0 1/100 0–1

 green rabbitbrush CHVI8 2/100 3/67 1/100 3/100 0–5

 bitterbrush PUTR2 0 3/67 0 3/100 0–5

 wax currant RICE 6/50 1/33 4/100 0 0–6

Grasses:

 bluebunch wheatgrass AGSP 8/100 12/100 10/100 1/100 5/20

 Idaho fescue FEID 38/100 9/100 2/100 5/100 8–50

 prairie junegrass KOCR 10/50 1/33 0 0 0–10

 Sandberg’s bluegrass POSA12 8/50 8/100 5/100 20/100 0–10

Forbs:

 common arrow ACMIL 6/50 3/100 1/100 2/100 0–6

 narrowleaf pussytoes ANST2 2/50 2/33 0 2/100 0–2

 creamy buckwheat ERHE2 2/100 1/100 1/100 0 1–2

 groundsel SENEC 2/100 1/33 8/100 2/100 0–2

Management considerations—

Light to moderate fires tend to reduce juniper and big 

sagebrush without harming ponderosa pine and bunchgrasses. Plants commonly found in this plant association that tend 

to increase with disturbances to the ground surface are 

rabbitbrush, creamy buckwheat, yarrow, bluegrasses, and 

annual bromes. These communities are high in layer 

diversity with resultant wildlife species habitat diversity. 

However, heavy use by ungulates (especially cattle and elk) 

can degrade these communities with compaction to the soils 

and overuse of bunchgrasses and a resultant loss in plant 

vigor. Rabbitbrush, cheatgrass, and bluegrasses often 

increase as a result.

Relationship to other studies— 

Volland’s (1976) classification in the central Oregon 

pumice zone contains a PIPO/PUTR2-ARTRV/FEIDAGSP plant association that is floristically similar to this 

association. Johnson and Clausnitzer (1992) classified and 

described this plant association for the Blue and Ochoco 

Mountains.
26

GENERAL TECHNICAL REPORT PNW-GTR-641

Ponderosa pine/Idaho fescue plant association

Pinus ponderosa/Festuca idahoensis

PIPO/FEID CPG112 N = 22

Sugar Creek, Paulina RD, Ochoco NF.

Distribution— 

Throughout the Blue and Ochoco Mountains.

Environmental features— 

This plant association was found on basalt, andesite, rhyolite, tuff, peridotite, and serpentine rocks. Elevations ranged 

from 3,800 to 5,300 ft (mean 4,592 ft). Slopes were generally gentle to moderate (mean 15 percent). Sampled sites were 

found on all aspects. Soils consisted of a loamy surface layer 

6 to 18 in thick, over very to extremely gravelly loamy soil. 

Bedrock occurred in some profiles, at depths as shallow as 

12 in but often not within 40 in of the surface. Available water capacity varied greatly, and soil pH was slightly acid to 

nearly neutral.

Mean Range

Elevation (feet) 4,592 3,800–5,300

Slope (percent) 15 1–80

Soil pH (n = 13) 6.2–7.2

Soil available water capacity 2–10 (low to high)

 (inches, n = 14)

Depth to bedrock or extremely 12–40+

 gravelly soil (inches, n = 15)

Herbage (pounds/acre, n = 18) 347 200–497

Aspect (number of plots) NW (5), NE (5), SE (5), SW (7)

Lithology Basalt, rhyolite, tuff, andesite, 

 peridotite, serpentine

Position Summit and all slope positions

Slope shape Convex, concave, straight

Ground surface features—

Phase

A B C A + B

(n = 11) (n = 9) (n = 2) range

Cover (%)

Bare ground 7 3 6 0–40

Bedrock 2 2 0 0–12

Rock 4 3 2 0–15

Gravel 1 0 1 0–10

Pavement 2 1 0 0–16

Mosses and lichens 1 2 0 0–10

Litter 83 89 91 0–10

Vegetation composition— 

Idaho fescue dominates beneath ponderosa pine. Western juniper may be associated. Shrubs are absent or present at low coverage; mountain big sagebrush and bitterbrush 

are the most common. Other bunchgrasses frequently found 

with fescue are bluebunch wheatgrass, prairie junegrass, and 

Sandberg’s bluegrass. As this type approaches Douglas-fir 

and grand fir forest, elk sedge may occur on moister microsites within the fescue community. The most common forb 

is yarrow. Also frequent are fleabanes, pussytoes, hawkweeds, and lupines.

States and transitions— 

Three phases were defined as follows:

A Idaho fescue cover >25 percent.

B Idaho fescue cover 15 to 25 percent; annuals 

present in minor amount.

C Idaho fescue cover <15 percent; annuals (e.g., 

annual bromes) and bulbous bluegrass cover 

≥10 percent; perennial forbs (e.g., twin arnica) 

may be abundant also.
27

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Principal species—

Phase

A B C A + B

Species Code (n = 11) (n = 9) (n = 2) range

Cover (%)/constancy (%) Cover (%)

Trees:

 ponderosa pine PIPO 29/100 32/100 28/100 7–60

 western juniper JUOC 1/55 7/67 0 0–33

Shrubs:

 mountain big sagebrush ARTRV 2/36 5/11 0 0–7

 bitterbrush PUTR2 1/45 2/56 0 0–4

Grasses and grasslikes:

 Idaho fescue FEID 36/100 21/100 10/100 15–60

 bluebunch wheatgrass AGSP 10/91 4/67 16/100 0–31

 cheatgrass BRTE 0 1/22 10/50 0–1

 prairie junegrass KOCR 1/55 3/22 2/100 0–4

 Sandberg’s bluegrass POSA12 2/55 1/67 1/50 0–15

 elk sedge CAGE2 4/64 6/22 0 0–6

Forbs:

 common yarrow ACMIL 3/100 2/89 3/100 0–7

 hawksbeards CREPI 1/55 1/33 0 0–2

 pussytoes ANTEN 2/55 1/44 22/100 0–8

 fleabanes ERIGE2 3/55 1/33 1/50 0–5

 lupines LUPIN 2/55 1/44 1/50 0–20

Phase B is probably produced by moderate grazing 

pressure. Overgrazing can take the association to phase 

C where weedy annual grasses or perennial forbs increase 

to the detriment of the bunchgrasses. Fires of light to 

moderate severity do not harm the pines or Idaho fescue, 

whereas severe fires can eliminate both.

Management considerations— 

Prescribed burns can promote new pines and young 

bunchgrass plants. These communities are especially 

valuable to grazing ungulates in the early spring when the 

fescue plants are preferred because of their succulence.

Relationship to other studies—

PIPO/FEID was first described in eastern Washington by Daubenmire and Daubenmire (1968), in the Blue 

Mountains by Hall (1973), in Montana by Pfister et al. 

(1977), in central Idaho by Steele et al. (1981), in northern Idaho by Cooper et al. (1991), in northern Washington by Clausnitzer and Zamora (1987), in the Wallowa 

and Seven Devils Mountains by Johnson and Simon 

(1987), and in the Blue and Ochoco Mountains by 

Johnson and Clausnitzer (1992).
28

GENERAL TECHNICAL REPORT PNW-GTR-641

Deep Creek canyon, Whitman Unit, Wallowa-Whitman NF.

Ponderosa pine/bluebunch wheatgrass plant association

Pinus ponderosa/Agropyron spicatum

PIPO/AGSP CPG111 N = 10

Principal species—

Phase

Species Code A + B (n = 10)

Cover (%)/constancy (%)

Trees:

 ponderosa pine PIPO 20/100

 western juniper JUOC 3/40

Shrubs:

 bitterbrush PUTR2 2/40

 common snowberry SYAL 2/40

Grasses and grasslikes: 

 bluebunch wheatgrass AGSP 31/100

 Idaho fescue FEID 4/60

 Wheeler’s bluegrass PONEW 4/30

 Sandberg’s bluegrass POSA12 7/90

 elk sedge CAGE2 5/50

Forbs: 

 common yarrow ACMIL 5/80

 serrate balsamroot BASE2 2/30

 fleabanes ERIGE2 2/40

 creamy buckwheat ERHE2 1/50

 western hawkweed HIAL 1/40

 lomatiums LOMAT 1/30

 tailcup lupine LUCA 10/40

 false agoseris MITR5 2/30

Distribution— 

Occurs throughout the Blue Mountains; most prominent 

in the northern Blues.

Environmental features— 

This plant association occurs on basalts, andesites, and 

volcanic tuff. Elevations ranged from 2,175 to 4,940 ft (mean 

4,164 ft). Slopes were moderate (mean 24 percent). Sampled 

sites were mostly on convex surfaces. Soils consisted of a 

surface layer of gravelly to very gravelly loamy soil, overlying extremely gravelly soil or weathered bedrock at a depth 

of 8 to 18 in. Available water capacity was low to moderate, 

and soil pH slightly acid to neutral.

Mean Range

Elevation (feet) 4,164 2,175-4,940

Slope (percent) 24 4–50

Soil pH (n = 3) 6.4–7.0

Soil available water capacity 1–5 (low to moderate)

 (inches, n = 8)

Depth to bedrock or extremely 8–18

 gravelly soil (inches, n = 8)

Herbage (pounds/acre, n = 9) 390 200–750

Aspect (number of plots) NW (0), NE (3), SE (5), SW (2)

Lithology Basalt, andesite, tuff

Position Summit, all slope positions

Slope shape Convex

Ground surface features—

Phase

A + B (n = 10)

Cover (%)

Bare ground 3

Bedrock 10

Rock 9

Gravel 0

Pavement 2

Mosses and lichens 1

Litter 75

Vegetation composition— 

Ponderosa pine occurs in open savannah over a bluebunch 

wheatgrass-dominated herbaceous layer. Western juniper 

may be present. Bitterbrush and common snowberry are 

infrequent and have low cover in this type. Bunchgrasses 

often associated with the bluebunch wheatgrass are Sandberg’s bluegrass and Idaho fescue. Elk sedge may be a 

component on mesic microsites adjacent to Douglas-fir or 

grand fir forests. The most common forb is yarrow. Fleabanes, western hawkweed, tailcup lupine, and creamy 

buckwheat often occur.

Fred Hall
29

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Ponderosa pine/squaw apple plant community type

Pinus ponderosa/Peraphyllum ramosissimum

PIPO/PERA4 CPS8 N = 2

This community was found in the central and southern 

Blue Mountains at relatively low elevations (below 4,500 ft). 

These are transitional communities between nonforest and 

forest sites. They contain a rich shrub component beneath a 

savannah of ponderosa pine and western juniper. Squaw apple is dominant with bitterbrush, snowberries, and mountain 

mahogany often associated. Elk sedge and the bunchgrasses occur together as members from adjacent forest and nonforest, respectively. Bluebunch wheatgrass and bottlebrush 

squirreltail are often prominent. Creamy buckwheat is the 

most frequent forb. Squaw apple has a relatively restricted 

and sporadic distribution in northeastern Oregon.

Ponderosa pine-western juniper/mountain mahogany-mountain snowberry plant community type

Pinus ponderosa-Juniperus occidentalis/Cercocarpus ledifolius-Symphoricarpos oreophilus

PIPO-JUOC/CELE3-SYOR2 CPC212 N = 2

This community was found in the southern Blue Mountains at moderate elevations (4,700 to 5,100 ft). The one soil 

studied was very shallow (4 in of gravelly sandy loam over 

bedrock), with very low available water capacity and neutral 

pH. These are transitional communities between open sagebrush-grasslands and forests. Ponderosa pines are scattered 

(10 percent overstory cover) over a shrubland dominated by 

mountain mahogany and mountain snowberry. Three bunchgrasses dominate the herbaceous vegetation: Idaho fescue, 

bluebunch wheatgrass, and prairie junegrass. Forbs are scant 

with yarrow and arrowleaf balsamroot the most frequently found. Mule deer (Odocoileus hemionus) heavily browse 

mountain mahogany shrubs.

States and transitions—

AB The deep-rooted bluebunch wheatgrass dominates 

over the other bunchgrasses. Perennial forbs occur 

at coverages of 5 percent or less.

C Sandberg’s bluegrass, lupines, and yarrow have 

increased owing to grazing disturbance.

Management considerations— 

Fire is often discontinuous in these communities. Fire 

return intervals are 8 to 10 years. Burning maintains 

bunchgrass vigor. Ungulates use these communities in 

spring and early summer for forage and in late summer 

for shading beneath the trees. Ungulates can degrade 

these sites if trampling causes displacement of bunchgrass 

plants on steep slopes early in the growing season when 

soils are saturated with rains and snowmelt.

Relationship to other studies— 

This plant association was first described by Daubenmire 

and Daubenmire (1968) in eastern Washington, in the 

Blue Mountains by Hall (1973), in Montana by Pfister et 

al. (1977), in central Idaho by Steele et al. (1981), in north 

Idaho by Cooper et al. (1991), in northern Washington by 

Clausnitzer and Zamora (1987), in the Wallowa and Seven 

Devils Mountains by Johnson and Simon (1987), and in the 

Blue and Ochoco Mountains by Johnson and Clausnitzer 

(1992).
30

GENERAL TECHNICAL REPORT PNW-GTR-641

Western juniper/mountain mahogany/Idaho fescue-bluebunch wheatgrass plant association 

Juniperus occidentalis/Cercocarpus ledifolius/Festuca idahoensis-Agropyron spicatum 

JUOC/CELE3/FEID-AGSP CJS41 N = 4

Western Juniper Series

Distribution— 

Southern Blue and Ochoco Mountains.

Benchmark site—

Birch Creek Three-Way Exclosure, Blue Mountain RD, 

Malheur NF. Established in 1961.

Environmental features— 

This plant association was found on basalt, rhyolite, and 

argillite. Elevations of sample plots ranged from 4,240 to 

5,270 ft (mean 4,903 ft). Slopes were moderate to steep 

(mean 26 percent). Plots occurred on westerly aspects on 

convex surfaces. Slope positions were on summits, shoulders, and backslopes. The one soil profile studied in detail 

had 8 in of very to extremely gravelly sandy loam over 

bedrock at a depth of 8 in; other brief investigations confirmed that soils were very shallow and had very low 

available water capacity.

Birch Creek exclosure, Blue Mountain RD, Malheur NF.

Mean Range

Elevation (feet) 4,903 4,240–5,270

Slope (percent) 26 12–40

Herbage (pounds/acre, n = 4) 368 240–540

Aspect (number of plots) NW (2), NE (0), SE (0), SW (2)

Lithology Basalt, rhyolite, argillite

Position Summit, shoulder, backslope

Slope shape Convex

Ground surface features—

Phase

A B D A + B

(n = 1) (n = 2) (n = 1) range

Cover (%)

Bare ground 5 8 17 5–10

Bedrock 3 9 0 3–15

Rock 20 12 4 5–20

Gravel 0 0 0 0

Pavement 60 8 6 0–60

Mosses and lichens 5 14 4 0–30

Litter 7 49 68

Vegetation composition— 

Western juniper forms a savannah over mountain mahogany and bunchgrasses. Idaho fescue requires the shading and moisture retention provided by the overtopping 

junipers. Forbs are few and have low coverage. Needlegrasses are the dominant invasive species and increase 

with disturbance. Communities in this association usually 

contain old-growth juniper and reflect long-term juniper 

occupancy.

States and transitions— 

Three phases were defined as follows:

A Idaho fescue dominates over other bunchgrasses, 

with cover >25 percent.

B Bluebunch wheatgrass dominates over other 

bunchgrasses, with cover >25 percent; needlegrasses occur and often codominate with fescue.

D Needlegrasses dominate over other bunchgrasses.
31

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

As the transition occurs from A to B to D, Sandberg’s 

bluegrass increases owing to the effect of disturbances by 

grazing and drought. Soil surface disturbance promotes the 

invasion and subsequent increase by needlegrasses. Herbage levels declined from phase A (450 lb/ac) to B (390 lb/ac) 

to D (240 lb/ac) on sampled plots. This decline mirrors the 

change from the larger, denser fescue and wheatgrass plants 

to the smaller, less dense bluegrass and needlegrass plants 

prominent in stage D.

Principal species—

Phase

A B D A + B

Species Code (n = 1) (n = 2) (n = 1) range

Cover (%)/constancy (%) Cover (%)

Trees:

 western juniper JUOC 10/100 25/100 10/100 10–30

Shrubs: 

 mountain mahogany CELE3 35/100 18/100 20/100 15–35

 bitterbrush PUTR2 0 1/50 1/100 0–1

Grasses:

 bluebunch wheatgrass AGSP 5/100 25/100 0 5–25

 soft brome BRMO2 0 3/50 0 0–3

 cheatgrass BRTE 0 5/100 0 0–5

 Idaho fescue FEID 25/100 8/100 0 5–25

 prairie junegrass KOCR 0 3/100 1/100 0–3

 Sandberg’s bluegrass POSA12 5/100 8/100 14/100 5–10

 needlegrasses STIPA 0 13/100 34/100 0–20

Forbs:

 common yarrow ACMIL 1/100 2/100 2/100 1–3

 pussytoes ANTEN 0 2/100 1/100 0–2

 stonecrops SEDUM 3/100 1/100 29/100 0–3

Management considerations—

This community is important for providing habitat edge 

and cover for wildlife (mammals and birds). The juxtaposition of these communities on the landscape increases habitat 

diversity. Fires may severely damage juniper and mahogany 

owing to their susceptibility to moderate and severe burns. 

Wild browsers and livestock have prevented recruitment of 

young mountain mahogany plants in many places.

Relationship to other studies— 

Western juniper/mountain mahogany/Idaho fescuebluebunch wheatgrass was previously described as an 

incidental community in the Blue and Ochoco Mountains 

by Johnson and Clausnitzer (1992). The findings of this 

study change the status of the vegetation to plant association.
32

GENERAL TECHNICAL REPORT PNW-GTR-641

Western juniper/bitterbrush/Idaho fescue-bluebunch wheatgrass plant association

Juniperus occidentalis/Purshia tridentata/Festuca idahoensis-Agropyron spicatum

JUOC/PUTR2/FEID-AGSP CJS321 N = 13

Skookum Exclosure, Heppner RD, Malheur NF.

Distribution— 

Central and southern Blue Mountains; Ochoco 

Mountains.

Benchmark sites—

Three exclosures contain excellent examples of this 

plant association:

• Skookum Three-Way Exclosures (established 1945); 

Heppner RD, Umatilla NF

• Dry Creek Three-Way Exclosures (established 

1939); Blue Mountain RD, Malheur NF

• Antelope Springs Exclosure (established 1955); 

Blue Mountain RD, Malheur NF

Environmental features—

This plant association was found on basalt, andesite, argillite, rhyolite, dacite, and pumice. Elevations ranged from 

3,650 to 5,140 ft (mean 4,253 ft). Slopes were gentle to steep 

(mean 12 percent). Plots occurred on all aspects on convex, 

straight, and undulating surfaces. Plot locations were on all 

slope positions. Brief soil investigations suggest that soils 

have shallow to moderate depth (6 to 22 in, n = 10).

Vegetation composition— 

These communities consist of a tree-shrub-bunchgrassforb mosaic beneath an open juniper savannah. Three 

bunchgrasses are prominent: Idaho fescue, bluebunch 

wheatgrass, and Sandberg’s bluegrass. Forbs are subordinate 

to the bunchgrasses; yarrow, blepharipappus, and red avens 

are plants frequently associated in the community. These 

deeper soil sites may have been free of western juniper 

prior to the decreased fire frequency and heavy grazing 

of the postsettlement period.

States and transitions— 

Five phases were recognized:

A Idaho fescue cover of at least 20 percent; bare soil 

covers <35 percent of the ground surface.

B Idaho fescue cover of <20 percent or bare ground 

>35 percent.

C1 Bitterbrush and Idaho fescue each with cover 

<5 percent; annual grasses and forbs prominent.

C2 Bitterbrush still present with 10 percent cover or 

more, but Idaho fescue is very weak (<5 percent 

cover) or absent.

D Introduced perennial grasses have replaced Idaho 

fescue and bluebunch wheatgrass.

Animal use has determined the composition and cover of bunchgrasses in these communities. Livestock seek 

shade under the junipers and can destroy the fescue, which 

is then replaced by annual plants, especially cheatgrass and 

Japanese brome. Prolonged heavy grazing combined with 

browsing of the bitterbrush component results in phase C1. 

Where severity or duration of bitterbrush browsing has been 

less severe but fescue has been impacted, phase C2 results. 

Phase D results when the deep-rooted bunchgrasses (FEID, 

AGSP) are overgrazed to the point where natural recolonization is not possible and land managers have seeded exotic 

grasses.

Ground surface features—

Phase

A B C1 C2 D A + B

Species (n = 4) (n = 4) (n = 2) (n = 2) (n = 1) range

Cover (%)

Bare ground 18 24 58 30 25 1–50

Bedrock 0 1 0 0 0 0–3

Rock 2 11 20 8 0 0–30

Gravel 2 3 5 5 10 0–10

Pavement 11 2 0 8 0 0–35

Mosses and lichens 1 2 1 4 0 0–4

Litter 66 57 16 45 65

Mean Range

Elevation (feet) 4,253 3,650–5,140

Slope (percent) 12 3–45

Herbage (pounds/acre, n = 7) 546 300–813

Aspect (number of plots) NW (2), NE (4), SE (4), SW (3)

Lithology Basalt, andesite, argillite, rhyolite, 

 dacite, pumice

Position Summit, shoulder, slopes

Slope shape Convex, straight, undulating
33

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Principal species—

Phase

A B C1 C2 D A + B

Species Code (n = 4) (n = 4) (n = 2) (n = 2) (n = 1) range

Cover (%)/constancy (%) Cover (%)

Trees: 

 western juniper JUOC 13/100 17/100 4/100 8/100 11/100 10–38

Shrubs:

 bitterbrush PUTR2 14/100 12/100 2/100 18/100 20/100 3–20

Grasses:

 bluebunch wheatgrass AGSP 14/100 15/100 15/100 12/100 1/100 1–30

 annual bromes BROMU 5/25 4/50 11/100 8/100 1/100 0–15

 Idaho fescue FEID 25/100 18/100 2/100 0 0 10–35

 prairie junegrass KOCR 2/50 2/50 0 3/50 0 0–3

 Sandberg’s bluegrass POSA12 8/100 8/100 5/100 4/100 10/100 3–20

Forbs:

 common yarrow ACMIL 4/100 6/100 5/100 1/100 3/100 1–15

 blepharipappus BLSC 6/50 3/50 22/100 2/100 0 0–10

 tall annual willowherb EPPA2 1/25 0 5/50 10/100 0 0–1

 sulphur-flower buckwheat ERUM 1/50 1/50 0 0 0 0–1

 red avens GETR 3/50 1/25 0 0 0 0–5

 phloxes PHLOX 2/25 4/50 3/50 2/100 1/100 0–5

Management considerations— 

The bitterbrush-bunchgrass mix provides for highquality wildlife habitat. These communities are heavily 

used by livestock and big game animals for shade. They 

are also primary deer winter range. Deer use is high for 

bedding and for browse (bitterbrush and juniper). 

Retention of viable populations of bitterbrush and 

bunchgrasses is desirable for biological diversity. Fire 

usually reduces the fire-sensitive juniper and bitterbrush; 

fire will promote bunchgrasses if adequate amounts 

remain to colonize the openings created by the death 

of juniper and bitterbrush. Most of these sites probably 

represent postsettlement juniper invasion, and juniper 

density may continue to increase in the future. Juniper 

density could increase to the point where shrubs are 

nearly eliminated.

Relationship to other studies— 

This plant association was originally described by 

Volland (1976) in the central Oregon pumice area. It 

was subsequently described by Johnson and Clausnitzer 

(1992) for the Blue and Ochoco Mountains.
34

GENERAL TECHNICAL REPORT PNW-GTR-641

Western juniper/low sagebrush/Idaho fescue plant association

Juniperus occidentalis/Artemisia arbuscula/Festuca idahoensis

JUOC/ARAR8/FEID CJS112 N = 3

South Fork of Wind Creek, Paulina RD, Ochoco NF.

Distribution— 

Central and southern Blue Mountains; Ochoco 

Mountains.

Environmental features— 

This plant association was found on basalts and andesites at elevations ranging from 4,400 to 4,890 ft (mean 

4,588 ft). Slopes were gentle (mean 5 percent). Plots 

occurred on southerly aspects on convex and straight 

surfaces. The one soil profile studied consisted of loam 

and gravelly loam, over bedrock at a depth of 12 in, with 

low available water capacity and neutral pH.

Mean Range

Elevation (feet) 4,588 4,400–4,890

Slope (percent) 5 4–5

Herbage (pounds/acre n = 3) 550 350–800

Aspect (number of plots) NW (0), NE (0), SE (2), SW (0)

Lithology Basalt, andesite

Position Summit, shoulder, backslope

Slope shape Convex, straight

bunch wheatgrass, Idaho 

fescue, and Sandberg’s 

bluegrass. These communities often were adjacent 

to low sagebrush/Idaho 

fescue-bluebunch 

wheatgrass (ARAR8/

FEID-AGSP) communities or low sagebrush/

Sandberg’s bluegrass 

(ARAR8/POSA12) 

communities. These communities usually contain old-growth 

juniper and reflect long-term occupancy by the species.

Ground surface features—

Phase

A (n = 2) C (n = 1)

Cover (%)

Bare ground 11 40

Bedrock 3 0

Rock 4 15

Gravel 3 15

Pavement 0 0

Mosses and lichens 1 1

Litter 78 29

Principal species—

Phase

Species Code A (n = 2) C (n = 1)

Cover (%)/constancy (%)

Trees:

 western juniper JUOC 19/100 19/100

Shrubs:

 low sagebrush ARAR8 20/100 20/100

Grasses:

 bluebunch wheatgrass AGSP 25/100 1/100

 Idaho fescue FEID 16/100 15/100

 Sandberg’s bluegrass POSA12 18/100 11/100

Vegetation composition— 

Western juniper forms a savannah over low sagebrush 

and bunchgrasses. The principal bunchgrasses are blueStates and transitions— 

Two phases were recognized:

A Bluebunch wheatgrass, Idaho fescue, and 

Sandberg’s bluegrass combined cover >50 percent.

C Combined cover of the three bunchgrasses is 

<50 percent; bare ground >20 percent.

The transition from phase A to C occurs as a result of 

heavy grazing by domestic livestock.

Management considerations— 

Juniper affords shade to livestock and wild ungulates. 

The juniper/low sagebrush/fescue community has high 

value to grazing animals and browsing animals. Deer relish 

the succulent leaders of the sagebrush. The mix of bunchgrasses provides a diverse offering to grazing animals.

Relationship to other studies— 

The JUOC/ARAR8/FEID plant association was first 

described by Hopkins (1979b) on the Fremont NF in southcentral Oregon. This type was previously described as a 

plant community for the Blue and Ochoco Mountains 

(Johnson and Clausnitzer 1992).
35

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Shake Table, Blue Mountain RD, Malheur NF.

Western juniper/Idaho fescue-bluebunch wheatgrass plant association 

Juniperus occidentalis/Festuca idahoensis-Agropyron spicatum

JUOC/FEID-AGSP CJG111 N = 8

Distribution— 

Central and southern Blue Mountains; Ochoco 

Mountains.

Benchmark sites— 

Kelly Creek Butte (proposed research natural area), 

Heppner RD, Umatilla NF; Shaketable (proposed research natural area), Blue Mountain RD, Malheur NF

Environmental features— 

This plant association was found on andesite and 

rhyolite. Elevations ranged from 3,050 to 5,850 ft 

(mean 4,651 ft). Slopes were gentle to steep (mean 27 

percent). Plots occurred primarily on westerly aspects 

on summits, shoulders, and backslopes. Brief soil investigations suggested shallow to moderately deep 

soils (10 to 30 in, n = 3).

Mean Range

Elevation (feet) 4,651 3,050–5,850

Slope (percent) 27 5–70

Herbage (pounds/acre, n = 7) 619 300–948

Aspect (number of plots) NW (3), NE (1), SE (0), SW (4)

Lithology Andesite, rhyolite

Position Summit, shoulder, backslope

Slope shape Convex, straight, undulating

Ground surface features—

Phase

A B C A + B

(n = 3) (n = 4) (n = 1) range

Cover (%)

Bare ground 6 12 15 0–20

Bedrock 1 0 0 0–4

Rock 22 18 30 0–65

Gravel 0 5 0 0–10

Pavement 0 0 10 0

Mosses and lichens 14 12 0 3–25

Litter 57 53 45

deeper soil sites may have been free of western juniper 

prior to the decreased fire frequency and heavy grazing 

of the postsettlement period.

Principal species—

Phase

A B C A + B

Species Code (n = 3) (n = 4) (n = 1) range

Cover (%)/constancy (%) Cover (%)

Trees:

 western juniper JUOC 22/100 27/100 8/100 8–45

Shrubs:

 wax currant RICE 1/33 2/50 0 0–4

Grasses:

 bluebunch wheatgrass AGSP 16/100 10/100 10/100 3–30

 cheatgrass BRTE 1/33 9/75 3/100 0–15

 Idaho fescue FEID 37/100 20/100 5/100 15–50 

 prairie junegrass KOCR 5/33 4/50 0 0–5 

 Sandberg’s bluegrass POSA12 6/67 9/100 7/100 0–20

Forbs:

 common yarrow ACMIL 4/100 1/50 1/100 0–10

 arrowleaf balsamroot BASA3 3/33 2/100 0 0–5

 tall annual willowherb EPPA2 0 2/50 0 0–3

 creamy buckwheat ERHE2 5/33 3/25 0 0–5

 red avens GETR 6/67 0 0 0–10

 tailcup lupine LUCA 6/67 8/75 0 0–20

Vegetation composition— 

Western juniper forms a savannah with bunchgrasses. 

The four principal bunchgrasses (Idaho fescue, bluebunch 

wheatgrass, prairie junegrass, Sandberg’s bluegrass) dominate the herbaceous layer. The most common forbs are 

yarrow, red avens, and tailcup lupine. Adjacent vegetation 

is often of thinner soil communities (stiff sage/Sandberg’s 

bluegrass; Sandberg’s bluegrass-onespike oatgrass). These 

States and transitions—

Three phases were defined as follows:

A Idaho fescue, bluebunch wheatgrass, and prairie 

junegrass cover total ≥50 percent.

B Idaho fescue, bluebunch wheatgrass, and prairie 

junegrass cover total 20 to 49 percent.

C Idaho fescue, bluebunch wheatgrass, and prairie 

junegrass cover total <20 percent.

Livestock seeking shade and grazing impact the bunchgrasses. In phase B, a reduction in cover of large bunchgrasses and increase in Sandberg’s bluegrass is attributed 
36

GENERAL TECHNICAL REPORT PNW-GTR-641

Western juniper/stiff sagebrush plant community type

Juniperus occidentalis/Artemisia rigida

JUOC/ARRI2 CJS811 N = 2

Western juniper is scattered over a xeric shrubland of stiff 

sagebrush with bunchgrasses strongly associated. Juniper 

averaged 11 percent cover; sagebrush averaged 13 percent. 

These communities usually contain old-growth juniper and 

reflect long-term occupancy by the species. The two principal bunchgrasses are bluebunch wheatgrass and Sandberg’s 

bluegrass. In the plot that was lightly impacted by grazing, 

the cover of each grass was 20 percent, and with heavier 

grazing disturbance both bunchgrasses declined. Forbs 

frequently occurring were narrowleaf stonecrop, low 

pussytoes, bighead clover, penstemons, and phlox.

These communities were found in the central and 

southern Blue Mountains on basalt and andesite. Sites 

were rocky (mean cover 50 percent), with gentle slopes 

to grazing pressure. In phase C, Idaho fescue has been 

nearly eliminated by grazing. Forbs that tend to increase 

with disturbance are yarrow, tailcup lupine, and creamy 

buckwheat.

Management considerations— 

Fire usually kills young juniper. Grazing animals use 

these communities for shade and forage. Deer use the 

areas beneath juniper trees for rest and shade. Chukar 

(Alectoris chukar) and quail (Callipepla californica) use 

these communities as well. Most of these sites probably 

(mean 6 percent), and convex slope shape. The one soil 

studied had 10 in of gravelly to very gravelly loamy material 

over bedrock, very low available water capacity, and slightly acid pH. These are hot, dry sites where spring moisture is 

slight and drought severely limits plant growth.

Western juniper/stiff sagebrush communities are often 

ecotonal between ponderosa pine forests or savannahs and 

stiff sagebrush/Sandberg’s bluegrass scablands. Grazing and 

browsing animals use the juniper for shading and the sagebrush for browse. Heavy use of the sagebrush will cause 

hedging of the shrub and possible mortality. Heavy traffic and trampling accelerate frost heaving and soil erosion 

of the scabland soils. Herbage ranged from 75 to 275 lb/ac 

(mean 175 lb/ac), the lowest of any juniper community type. 

Western juniper/bluebunch wheatgrass plant community type

Juniperus occidentalis/Agropyron spicatum

JUOC/AGSP CJG113 N = 3

Western juniper is scattered over a xeric grassland composed of bluebunch wheatgrass and Sandberg’s bluegrass. 

The juniper cover averages 12 percent. The bunchgrasses are thinly scattered in a rocky-gravelly landscape (bluebunch wheatgrass average cover 17 percent; Sandberg’s 

bluegrass cover 8 percent). Other herbaceous plants are relatively few and have low cover. Sparse fuels suggest rare 

fires and possibly long-term juniper occupancy of these 

sites rather than recent juniper invasion.

These communities were found in the southern Blue and 

Ochoco Mountains. Sites were found on basalt and andesite, where rock cover averaged 33 percent and gravel 12 

percent. Elevations ranged from 3,990 to 4,515 ft (mean 

4,235 ft). Slopes were moderately steep (mean 24 percent). 

Plots occurred on southerly aspects on convex surfaces, at 

shoulder and backslope positions. The one soil investigated was just 4 in thick. These are hot, dry sites where spring 

moisture is slight and drought strongly limits plant growth.

These communities receive highest use in late winter to 

early spring when bunchgrasses green up and are available 

for forage before adjacent grasslands. Elk (Cervus elaphus) 

and deer are attracted to these communities when winter 

snow is receding from the mountain rangelands. Herbage 

ranged from 250 to 375 lb/ac (mean 312 lb/ac).

represent postsettlement juniper invasion, and juniper 

density may continue to increase in the future.

Relationship to other studies— 

A juniper/bunchgrass plant association was described 

by Hall (1973) for the Blue Mountains. Johnson and 

Simon (1987) described this plant association for the 

Wallowa Mountains and canyon lands of the Snake and 

Imnaha Rivers in northeastern Oregon. Johnson and 

Clausnitzer (1992) described this plant association for 

the Blue and Ochoco Mountains.
37

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Mountain mahogany/Idaho fescue-bluebunch wheatgrass plant association

Cercocarpus ledifolius/Festuca idahoensis-Agropyron spicatum

CELE3/FEID-AGSP SD4111 N = 5

Distribution—

Blue and Ochoco Mountains (more frequent in central 

and southern Blue Mountains).

Environmental features— 

This plant association was found on basalt, rhyolite, 

and tuff. Elevations ranged from 4,550 to 5,290 ft (mean 

4,931 ft). Slopes were gentle to moderately steep (mean 

14 percent). Plots occurred on northerly and southerly aspects on convex surfaces. Plots were on summit, 

shoulder, and footslope positions. The one soil studied 

consisted of very to extremely gravelly silt loam over 

bedrock at a depth of 15 in. Available water capacity 

was very low and the pH slightly acid.

Capps Mountain, Emigrant Creek RD, Malheur NF.

Mean Range

Elevation (feet) 4,931 4,550–5,290

Slope (percent) 14 4–35

Herbage (pounds/acre, n = 2) 345 280–410

Aspect (number of plots) NW (1), NE (2), SE (2), SW (0)

Lithology Basalt, rhyolite, tuff

Position Summit, shoulder, footslope

Slope shape Convex

Ground surface features—

Phase

A B C A + B 

(n = 1) (n = 2) (n = 2) range

Cover (%)

Bare ground 1 14 14 1–15

Bedrock 10 8 2 0–15

Rock 10 5 4 1–10

Gravel 0 0 0 0

Pavement 0 4 0 0–8

Mosses and lichens 8 16 0 6–25

Litter 71 36 65 35–60

Shrubland Series

Vegetation composition— 

Mountain mahogany, in relatively dense stands (up to 

65 percent cover), dominates over bunchgrasses. Western juniper and ponderosa pine may be present as incidental species. Idaho fescue is always present as the dominant 

deep-rooted bunchgrass in relatively undisturbed vegetation. Other grasses commonly occurring with fescue 

are bluebunch wheatgrass, bottlebrush squirreltail, and 

Wheeler’s and Sandberg’s bluegrasses. The most common 

forbs are yarrow, western hawkweed, western groundsel, 

and fleabanes.

States and transitions— 

Three phases were defined as follows:

A Idaho fescue and bluebunch wheatgrass cover totals 

>45 percent.

B Idaho fescue and bluebunch wheatgrass cover totals 

<45 percent; cover of bluegrasses >20 percent but 

little annual grass.

C Idaho fescue and bluebunch wheatgrass cover totals 

<30 percent and cheatgrass cover is ≥25 percent.

Large bunchgrasses decrease and bluegrasses increase 

with moderate ungulate trampling and traffic in these 

stands, resulting in phase B. Further heavy ungulate use 

continues to diminish the perennial grass cover and leads 

to dense stands of cheatgrass (phase C).
38

GENERAL TECHNICAL REPORT PNW-GTR-641

Mountain mahogany-bitterbrush/bluebunch wheatgrass plant community type

Cercocarpus ledifolius-Purshia tridentata/Agropyron spicatum

CELE3-PUTR2/AGSP SD4115 N = 1

Management considerations— 

These communities add to the overall landscape 

diversity within the coniferous forest and the sagebrush 

rangeland of the Blue and Ochoco Mountain landscapes. Mountain mahogany is preferentially browsed 

by deer, elk, and pronghorns (Antilocapra americana). 

There is very little recruitment of mountain mahogany 

owing to the heavy use of these stands by browsing 

ungulates. High lines or skirting of the mature shrub 

canopies can weaken the mature shrubs and lead to 

mortality. The dense thickets of mahogany provide 

excellent winter cover for deer. Moderate and severe 

fire usually kills mountain mahogany, and then regeneration is often severely curtailed by herbivory. If 

bunchgrass cover was low before the fire, weedy or 

invasive species may colonize the site after fire.

Relationship to other studies—

 Hall (1973) included CELE3/FEID-AGSP in a mountain mahogany-grass plant community type in the Blue 

Mountains. Three mountain mahogany plant community types were described in the Snake River canyon by 

Johnson and Simon (1987). This plant association was 

previously described in the Blue and Ochoco Mountains by Johnson and Clausnitzer (1992).

This community type was probably more common in 

the Blue Mountains prior to the introduction of domestic livestock and the high deer populations of the 1950s. 

Here bitterbrush is dominant beneath an open mahogany 

stand. It is present today owing to exclusion of ungulates 

beginning in 1961 at Birch Creek Three-Way Exclosure 

on the Blue Mountain RD of the Malheur NF. The xeric 

site (soil of gravelly sandy loam just 6 in deep) does not 

support Idaho fescue. The bunchgrasses that codominate 

here are bluebunch wheatgrass, Thurber’s needlegrass, 

and Sandberg’s bluegrass.

Mountain mahogany/bluebunch wheatgrass plant community type

Cercocarpus ledifolius/Agropyron spicatum

CELE3/AGSP SD4112 N = 3

These communities are found on southerly, steep slopes 

(mean 63 percent) on basalt and rhyolite outcrops. Extremely gravelly or stoney material occurs within 10 in of the surface. These sites are too dry for fescue establishment. The 

predominant bunchgrasses are bluebunch wheatgrass and 

Sandberg’s bluegrass. The mountain mahogany stands are 

open (mean cover 14 percent). Snowberries (both common and mountain) are usually associated. Common forbs 

are yarrow, creamy buckwheat, and lanceleaf stonecrop. 

This community occurs on Chicken Hill in the central Blue 

Mountains of the La Grande RD, Wallowa-Whitman NF.

Principal species—

Phase

A B D A + B

Species Code (n = 1) (n = 2) (n = 2) range

Cover (%)/constancy (%) Cover (%)

Trees:

 western juniper JUOC 0 5/50 0 0–5

Shrubs:

 mountain mahogany CELE3 45/100 40/100 68/100 14–65

 gray rabbitbrush CHNA2 10/100 1/50 0 0–10

Grasses:

 bluebunch wheatgrass AGSP 20/100 0 6/100 0–20

 rattlesnake brome BRBR7 0 0 7/50 0

 cheatgrass BRTE 5/100 0 32/100 0–5

 Idaho fescue FEID 30/100 32/100 11/100 23–40

 prairie junegrass KOCR 1/100 5/50 4/100 0–5

 Wheeler’s bluegrass PONEW 1/100 25/50 1/50 0–25

 Sandberg’s bluegrass POSA12 3/100 44/50 10/50 0–3

 bottlebrush squirreltail SIHY 1/100 4/100 5/50 1–8

Forbs:

 common yarrow ACMIL 1/100 1/100 2/100 1–1

 fleabanes ERIGE2 0 2/50 1/100 0–3

 creamy buckwheat ERHE2 0 2/50 1/50 0–2

 western hawkweed HIAL 5/100 0 1/50 0–5

 western groundsel SEIN2 3/100 10/50 4/50 0–10
39

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Mountain mahogany/Wheeler’s bluegrass plant community type

Cercocarpus ledifolius/Poa nervosa wheeleri

CELE3/PONEW SD4114 N = 1

This community in the southern Blue Mountains contains 

a high cover of Wheeler’s bluegrass (60 percent) beneath a 

dense stand of mountain mahogany (60 percent). Few forbs 

are represented. The only other bunchgrasses are bluebunch 

wheatgrass, western needlegrass, and Sandberg’s bluegrass. 

The site is high in elevation for mountain mahogany (6,050 

ft). The soil consists of very to extremely gravelly silt loam 

over bedrock at 18 in.

Bitterbrush-mountain big sagebrush/Idaho fescue-bluebunch wheatgrass plant association

Purshia tridentata-Artemisia tridentata var. vaseyana/Festuca idahoensis-Agropyron spicatum

PUTR2-ARTRV/FEID-AGSP SD3124 N = 6

Cougar Creek Exclosure, Prairie City RD, Malheur NF.

Distribution— 

Southern Blue Mountains; Ochoco Mountains.

Environmental features— 

This plant association was found on rhyolite and volcanic sandstone. Elevations of sample plots ranged from 4,600 

to 5,450 ft (mean 5,103 ft). Slopes were gentle to moderate (mean 7 percent). Plots occurred primarily on southerly 

slopes on straight surfaces near ridgetops. Soils depths were 

9 to 24 in (n = 3). The one profile studied in detail had clayrich subsoil and neutral pH.

Vegetation composition— 

Bitterbrush is always associated with mountain big 

sagebrush as a codominant. Bunchgrasses dominate the 

herbaceous layer. Always present in relatively undisturbed 

vegetation are Idaho fescue, prairie junegrass, bluebunch 

wheatgrass, and Sandberg’s bluegrass. Prominent forbs 

are yarrow, creamy buckwheat, and fleabanes. Ponderosa pine and western juniper may occur as incidental species at low cover. These shrublands are often adjacent to 

mountain big sagebrush communities.

States and transitions— 

Three phases were defined as follows:

A Bitterbrush cover >5 percent; Idaho fescue and 

bluebunch wheatgrass cover total >25 percent.

B Bitterbrush cover >5 percent; Idaho fescue and 

bluebunch wheatgrass cover total <25 percent.

C Bitterbrush cover >5 percent; Idaho fescue absent; 

Sandberg’s bluegrass is the dominant bunchgrass; 

bare ground >30 percent.

D Bitterbrush cover <5 percent.

Mean Range

Elevation (feet) 5,103 4,600–5,450

Slope (percent) 7 2–20

Herbage (pounds/acre, n = 1) 380

Aspect (number of plots) NW (0), NE (0), SE (5), SW (1)

Lithology Rhyolite, volcanic sandstone, tuff

Position Summit

Slope shape Straight

Ground surface features—

Phase

A B C D A + B

(n = 1) (n = 2) (n = 1) (n = 2) range

Cover (%)

Bare ground 15 14 40 18 13–15

Bedrock 0 2 0 0 0–4

Rock 0 8 1 1 0–10

Gravel 0 0 1 5 0–1

Pavement 0 0 0 0 0

Mosses and lichens 2 0 15 0 0–2

Litter 50 40 3 63 
40

GENERAL TECHNICAL REPORT PNW-GTR-641

Principal species—

Phase

 A B C D A + B

Species Code (n = 1) (n = 2) (n = 1) (n = 2) range

Cover (%)/constancy (%) Cover (%)

Trees:

 western juniper JUOC 0 1/50 1/100 0 0–1

 ponderosa pine PIPO 0 4/50 0 0 0–4

Shrubs:

 mountain big sagebrush ARTRV 20/100 9/100 30/100 28/100 9–20

 mountain mahogany CELE3 0 3/50 0 0 0–3

 bitterbrush PUTR2 15/100 12/100 25/100 2/100 8–16

 mountain snowberry SYOR2 0 2/50 0 0 0–2

Grasses:

 bluebunch wheatgrass AGSP 10/100 10/100 10/100 5/100 9–10

 Idaho fescue FEID 25/100 2/100 0 18/100 1–25

 prairie junegrass KOCR 3/100 2/100 0 1/100 1–3

 Sandberg’s bluegrass POSA12 5/100 8/100 15/100 10/100 2–15

 bottlebrush squirreltail SIHY 0 2/50 1/100 1/100 0–2

Forbs: 

 common yarrow ACMIL 1/100 4/100 10/100 1/100 1–6

 fleabanes ERIGE2 6/100 5/100 0 1/50 1–6

 creamy buckwheat ERHE2 1/100 2/100 1/100 10/50 1–2

With overgrazing, phase A will shift toward phase B with 

diminished cover by fescue and wheatgrass. As degradation 

of the bunchgrass community continues, phase C can be 

attained where the shallow-rooted Sandberg’s bluegrass 

dominates the deep-rooted bunchgrasses and Idaho fescue 

is relict or absent. With ungulate overbrowsing, bitterbrush 

is weakened and juvenile plants are killed resulting in relict 

PUTR2 as portrayed in phase D.

Management considerations— 

Bitterbrush is killed by moderately severe to severe burns 

when soil moisture is low and roots are consumed. Bitterbrush and mountain big sagebrush can be regenerated by 

using prescribed fire if burns are accomplished at the time 

soil moisture is adequate to protect the roots from extreme 

heat. Bitterbrush-sagebrush/bunchgrass communities are 

highly desired as winter-spring range for wildlife (especially deer). Mule deer are principal users of bitterbrush during 

winter. Domestic livestock use is focused on the bunchgrass 

component, but bitterbrush is hedged when livestock use is 

heavy. Regeneration of bitterbrush has been seriously compromised in many areas by combined browsing of livestock 

and wildlife.

Relationship to other studies— 

This is the first description of PUTR2-ARTRV/FEID 

AGSP as a plant association.
41

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Distribution— 

Central and southern Blue Mountains; Ochoco Mountains.

Environmental features— 

This plant association was found on basalt and rhyolite. 

Elevations of sample plots ranged from 3,690 to 4,700 ft 

(mean 4,199 ft). Slopes were gentle to moderately steep 

(mean 11 percent). Plots occurred primarily on southwesterly slopes on convex surfaces and on all slope positions. 

Soils consisted of a surface layer of loamy material about 

5 in thick over a clay-rich layer (sometimes stoney), with 

bedrock or extremely gravelly soil 10 to 30 in below the 

surface. Available water capacity was low to moderate, 

and soil pH was slightly acid to neutral.

Bitterbrush/Idaho fescue-bluebunch wheatgrass plant association

Purshia tridentata/Festuca idahoensis-Agropyron spicatum

PUTR2/FEID-AGSP SD3111 N = 7

Shake Table, Blue Mountain RD, Malheur NF.

Ground surface features—

Phase

A B C A + B

(n = 3) (n = 2) (n = 2) range

Cover (%)

Bare ground 18 45 32 3–50

Bedrock 2 0 0 0–4

Rock 4 2 0 0–5

Gravel 0 0 0 0

Pavement 5 2 0 0–15

Mosses and lichens 2 0 0 0–4

Litter 30 42 28

Mean Range

Elevation (feet) 4,199 3,690–4,700

Slope (percent) 11 3–35

Soil pH (n = 5) 6.2–7.3

Soil available water capacity 2–7 (low to moderate)

 (inches, n = 4)

Depth to bedrock or extremely 10–30

 gravelly soil (inches, n = 8)

Herbage (pounds/acre, n = 2) 470 437–502

Aspect (number of plots) NW (2), NE (1), SE (0), SW (4)

Lithology Basalt, tuff

Position Summit, shoulder, backslope, footslope

Slope shape Convex, straight

Vegetation composition— 

Bitterbrush occurs with bunchgrass-dominated herbaceous layer. Idaho fescue, bluebunch wheatgrass, and 

Sandberg’s bluegrass are always present in relatively 

undisturbed vegetation. Onespike oatgrass may be a 

component on shallow soil inclusions within the site. 

Prominent forbs are yarrow, hawksbeard, blepharipappus, 

and cryptantha. Ponderosa pine and western juniper may 

occur at low cover in this association. Bitterbrush/

bunchgrass shrublands are often adjacent to scablands, 

grasslands, juniper/bitterbrush, or pine-juniper/bitterbrush communities.

States and transitions— 

Three phases were defined as follows:

A Idaho fescue and bluebunch wheatgrass cover total 

>25 percent.

B Idaho fescue and bluebunch wheatgrass cover total 

<25 percent or bare ground is >30 percent.

C Sandberg’s bluegrass is the dominant bunchgrass; 

bare ground is >30 percent; annuals have >50 

percent cover.

With overgrazing, phase A will shift toward phase B 

with diminished cover by fescue and wheatgrass and an 

increase in bare ground. As degradation of the bunchgrass community continues, the shallow-rooted Sandberg’s bluegrass and annuals (e.g., blepharippaus, annual 

bromes) dominate over the deep-rooted bunchgrasses 

(phase C).
42

GENERAL TECHNICAL REPORT PNW-GTR-641

Principal species—

Phase

A B C A + B

Species Code (n = 3) (n = 2) (n = 2) range

Cover (%)/constancy (%) Cover (%)

Trees:

 ponderosa pine PIPO 3/33 1/50 0 0–3

 western juniper JUOC 2/33 8/50 0 0–5

Shrubs:

 bitterbrush PUTR2 14/100 18/100 6/100 10–25

 gray rabbitbrush CHNA2 0 5/50 0 0–5

Grasses:

 bluebunch wheatgrass AGSP 23/100 12/100 6/100 10–30

 rattlesnake brome BRBR7 1/33 0 1/50 0–1

 hairy brome BRCO4 1/33 0 0 0–1

 Japanese brome BRJA 0 0 18/100 0

 soft brome BRMO2 0 0 1/50 0

 cheatgrass BRTE 3/33 0 0 0–3

 onespike oatgrass DAUN 6/67 1/50 0 0–10

 Idaho fescue FEID 15/100 12/100 0 3–25

 prairie junegrass KOCR 1/33 1/50 0 0–1

 Sandberg’s bluegrass POSA12 9/100 8/100 18/100 1–15

 bottlebrush squirreltail SIHY 1/33 0 10/100 0–1

 ventenata VEDU 0 5/50 0 0–5

Forbs:

 common yarrow ACMIL 5/100 0 8/100 0–5

 tapertip onion ALAC4 1/33 3/50 0 0–3

 blepharipappus BLSC 10/33 10/50 22/100 0–10

 tapertip hawksbeard CRAC2 8/67 0 3/50 0–10

 cryptantha CRYPT 10/33 2/100 0 0–10

 tall annual willowherb EPPA2 1/33 1/50 22/100 0–1

 creamy buckwheat ERHE2 15/33 0 28/100 0–15

 spurred lupine LULA3 0 0 5/100 0

Management considerations— 

Bitterbrush is killed by moderately severe to severe 

burns when soil moisture is low and roots are consumed. Bitterbrush can be regenerated by using prescribed fire if soil moisture is adequate to protect the 

roots from extreme heat. Bitterbrush/bunchgrass communities are highly desired as winter-spring range for 

wildlife (especially deer). Mule deer are principal users of bitterbrush during winter. Domestic livestock 

use is focused on the bunchgrass component, but bitterbrush is hedged when livestock use is heavy. Regeneration of bitterbrush has been seriously compromised 

in many areas by combined browsing of livestock and 

wildlife.

Relationship to other studies— 

Daubenmire (1970) was the first ecologist to 

describe this vegetation with his PUTR2/FEID habitat 

type in central Washington. Hall (1973) classified a 

bitterbrush/bunchgrass plant community type in the 

southern Blue and Ochoco Mountains. Johnson and 

Simon (1987) described a PUTR2/FEID-AGSP plant 

association in the Wallowa Mountains. Johnson and 

Clausnitzer (1992) described the PUTR2/FEID-AGSP 

plant association of the Blue and Ochoco Mountains.

Bitterbrush-mountain big sagebrush/Idaho fescue plant community type

Purshia tridentata-Artemisia tridentata var. vaseyana/Festuca idahoensis

PUTR2-ARTRV/FEID SD3125 N = 1

This mesic bitterbrush community was found below Bald 

Butte on the old Snow Mountain RD, Ochoco NF (now the 

Emigrant RD, Malheur NF). Here bitterbrush was codominant with mountain big sagebrush. The bitterbrush was 

Bitterbrush/Douglas’ buckwheat plant community type

Purshia tridentata/Eriogonum douglasii

PUTR2/ERDO SD3126 N = 1

vigorous, with growth from 4 to 7 ft tall. Associated with 

the fescue were other mesic graminoids (e.g., mountain 

brome, giant wildrye, and elk sedge). The only prominent 

forb was western groundsel.

The bunchgrasses associated with bitterbrush in this 

community were relict owing to intense overgrazing over 

a long time. This community was dominated by Douglas’ 

buckwheat and desert yellow daisy. The site had lost soil 

to surface erosion as attested by an erosion pavement of 

65 percent. Soil depths averaged only 2.25 in. It was not 

possible to assign this plot to a bitterbrush plant association.
43

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Distribution— 

Central and southern Blue Mountains.

Environmental features— 

This plant association was found on basalt, andesite, 

rhyolite, tuff and graywacke. Elevations of sample plots 

ranged from 4,200 to 5,980 ft (mean 4,995 ft). Slopes were 

gentle to moderate (mean 16 percent). Plots occurred on all 

aspects; mainly on summits, shoulders, and backslopes; and 

primarily on convex or straight surfaces. Soils consisted of

 a sandy loam or silt loam surface, with increasing gravel 

content with depth and bedrock at a depth of more than 22 

in. Available water capacity was low to moderate and pH 

slightly acid to neutral.

Mountain big sagebrush/Idaho fescue-prairie junegrass plant association

Artemisia tridentata var. vaseyana/Festuca idahoensis-Koeleria cristata

ARTRV/FEID-KOCR SD2929 N = 17

Vegetation composition— 

The bunchgrasses—Idaho fescue, prairie junegrass, and 

bluebunch wheatgrass—dominated beneath the sagebrush. 

Frequently associated with them were Sandberg’s bluegrass 

and bottlebrush squirreltail. A diverse group of forbs occurred within the herbaceous layer. Prominent were yarrow, 

fleabanes, creamy buckwheat, tailcup lupine, and phlox. 

This is a highly productive community; herbage production 

averaged 667 lb/ac (the highest of all big sagebrush/bunchgrass plant associations), with one site producing over 1,600 

lb/ac.

States and transitions— 

Four phases were defined as follows:

A1 Sagebrush cover <10 percent; fescue, junegrass, 

and wheatgrass total cover >35 percent.

A2 Sagebrush cover >10 percent but <50 percent; 

fescue, junegrass, and wheatgrass total cover 

>35 percent; forb cover low to moderate.

B Sagebrush cover >10 percent and <50 percent; 

fescue, junegrass, and wheatgrass total cover 

20 to 35 percent; rich in forbs (lupines, paintbrushes, balsamroot).

C Sagebrush cover dense (≥50 percent); fescue, 

junegrass, and wheatgrass total cover <20 percent.

D Sagebrush cover low and Idaho fescue with little 

or no cover, but cover by junegrass and wheatgrass 

is fairly high (>30 percent).

Sagebrush density increases with lack of periodic fire and 

overgrazing. Phase A1 represents the community where 

fire has reduced the sagebrush cover and stimulated bunchgrasses. Phase A2 portrays a fairly dense stand of sagebrush 

where lack of fire has contributed to an increase in sagebrush but moderate grazing has not reduced the bunchgrass 

Bull Run Rock, Prairie City RD, Malheur NF.

Mean Range

Elevation (feet) 4,995 4,200–5,980

Slope (percent) 16 1–50

Soil pH (n = 6) 6.4–7.2

Soil available water capacity 2–7 (low to moderate)

 (inches, n = 6)

Depth to bedrock 22–40+

 (inches, n = 14)

Herbage (pounds/acre, n = 12) 667 275–1,621

Aspect (number of plots) NW (3), NE (4), SE (4), SW (6)

Lithology Basalt, andesite, rhyolite, tuff, 

 graywacke

Position Summit, backslope, shoulder, 

 footslope

Slope shape Convex, concave, straight

Ground surface features

Phase

A1 A2 B C D A + B

(n = 3) (n = 6) (n = 3) (n = 2) (n = 3) range

Cover (%)

Bare ground 17 15 20 5 27 3–25

Bedrock 2 0 0 0 2 0

Rock 9 1 5 8 8 0–2

Gravel 0 1 13 2 0 0–5

Pavement 2 5 0 8 3 0–20

Mosses and lichens 4 4 2 0 4 0–11

Litter 36 74 56 73 66
44

GENERAL TECHNICAL REPORT PNW-GTR-641

cover. Phase B is forb rich from increased grazing pressures. 

Phase C portrays a more degraded condition where heavy 

grazing and fire exclusion have tipped the balance further in 

favor of sagebrush and have further reduced the fescue cover. Phase D is probably caused by grazing or severe fire that 

nearly eliminated fescue but not bluebunch wheatgrass.

Management considerations— 

Mountain big sagebrush is damaged by fires of late summer when moisture is low in the soil. Cool burns when soils 

are moist allow some sagebrush to survive. Bunchgrasses 

Principal species—

Phase

A1 A2 B C D A + B

Species Code (n = 3) (n = 6) (n = 3) (n = 2) (n = 3) range

Cover (%)/constancy (%) Cover (%)

Shrubs:

 mountain big sagebrush ARTRV 6/100 26/100 32/100 55/100 5/100 6–35

 green rabbitbrush CHVI8 1/100 1/67 1/33 1/50 1/67 0–2

 gray horsebrush TECA2 1/33 1/33 1/33 0 1/33 0–1

Grasses:

 bluebunch wheatgrass AGSP 8/100 12/50 6/67 12/100 31/100 0–30

 Idaho fescue FEID 26/100 28/100 22/100 6/100 1/33 10–40

 prairie junegrass KOCR 14/100 8/100 11/100 10/100 10/100 1–20

 Sandberg’s bluegrass POSA12 23/100 5/83 8/100 5/50 12/67 0–38

 bottlebrush squirreltail SIHY 1/100 9/33 1/33 1/50 2/100 0–10

 needlegrasses STIPA 1/33 2/17 0 5/50 0 0–2

Forbs:

 common yarrow ACMIL 2/67 2/83 4/100 3/100 3/100 0–5

 arrowleaf balsamroot BASA3 0 2/17 12/67 1/100 1/33 0–15

 paintbrushes CASTI2 0 8/33 25/33 2/100 0 0–25

 tapertip hawksbeard CRAC2 1/33 1/17 1/67 1/50 0 0–1

 fleabanes ERIGE2 5/67 3/67 2/67 4/100 10/33 0–5

 creamy buckwheat ERHE2 2/100 2/100 1/67 13/100 2/100 0–5

 tailcup lupine LUCA 2/67 5/50 16/100 15/50 1/33 0–40

 phloxes PHLOX 4/67 2/67 1/33 0 0 0–6

 western groundsel SEIN2 1/33 10/17 1/67 1/50 0 0–10 

are stimulated by light and moderate burns. Severe burns in 

communities with dense sagebrush can do serious damage 

to Idaho fescue and allow colonization of the site by more 

disturbance-adapted species, such as western needlegrass. 

Needlegrasses are also promoted by overgrazing. Forbs that 

increase in these communities from disturbance are yarrow, 

paintbrushes, tailcup lupine, and creamy buckwheat.

Relationship to other studies— 

This is the first description of ARTRV/FEID-KOCR as 

a plant association.
45

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Mountain big sagebrush/Idaho fescue-bluebunch wheatgrass plant association

Artemisia tridentata var. vaseyana/Festuca idahoensis-Agropyron spicatum

ARTRV/FEID-AGSP SD2911 N = 44

Distribution— 

Central and southern Blue Mountains; Ochoco Mountains.

Benchmark sites—

Duck Creek Exclosure (1950), Jake Green Exclosure 

(1963), and Skookum Spring Exclosure (1963)—all on 

Emigrant Creek RD, Malheur NF.

Environmental features— 

This plant association was found on basalt, andesite, rhyolite, tuff, serpentine, and graywacke. Elevations of sample 

plots ranged from 4,520 to 7,650 ft (mean 5,615 ft). Slopes 

were gentle to steep (mean 19 percent). Plots occurred on all 

aspects (majority on southerly aspects); on summits, shoulders and backslopes; and on mostly convex surfaces. Soils 

consisted of a sandy loam or silt loam surface, with gravel 

content increasing with depth and extremely gravelly 

material at a depth of 12 to 40 in. Available water capacity 

was moderate and pH slightly acid to neutral.

Vegetation composition— 

Mountain big sagebrush forms an open shrubland with 

bunchgrasses dominating in the herbaceous layer. Green 

rabbitbrush is often associated. Idaho fescue is the most 

prominent bunchgrass. Usually present with it are bluebunch 

wheatgrass, prairie junegrass, and Sandberg’s bluegrass. 

Forbs associated with high frequency are yarrow, creamy 

buckwheat, hawksbeards, fleabanes, and lupines. Herbage 

production is similar to the ARTRV/FEID-KOCR plant association.

States and transitions— 

Seven phases were defined as follows:

A1 Sagebrush cover <20 percent; sum of fescue, 

wheatgrass, and junegrass cover >25 percent.

A2 Sagebrush cover <5 percent; bunchgrass cover 

low (postburn).

B Sagebrush cover 20 to 50 percent; sum of fescue, 

wheatgrass, and junegrass cover >25 percent.

C1 Sagebrush cover dense (>50 percent).

C2 Sagebrush cover moderately dense (10 to 50 

percent); sum of fescue, wheatgrass, and junegrass 

cover <25 percent; high in forbs or bare ground.

C3 Sagebrush cover <5 percent; sum of fescue, 

wheatgrass, and junegrass cover <10 percent; 

high percentage of bare ground and gravel (60 to 

80 percent) after fire in a dense sagebrush stand.

D Sagebrush cover low (<10 percent); needlegrass and 

creamy buckwheat dominant over the bunchgrasses 

(fifth year after a burn of dense sagebrush).

Sagebrush density increases with lack of periodic fire 

and overgrazing. Phase A1 represents the ARTRV/FEIDAGSP community where fire has periodically reduced sagebrush and favored bunchgrasses. Phase A2 portrays the first 

Marking Corrals Basin, Emigrant Creek RD, Malheur NF.

Mean Range

Elevation (feet) 5,615 4,520–7,650

Slope (percent) 19 2–55

Soil pH (n = 8) 6.0–7.0

Soil available water capacity 4–6.5 (moderate)

 (inches, n = 8)

Depth to bedrock or extremely 12–40

 gravelly soil (inches, n = 20)

Herbage (pounds/acre, n = 16) 654 256–1,050

Aspect (number of plots) NW (10), NE (6), SE (11), SW (17)

Lithology Basalt, rhyolite, tuff, andesite, 

 serpentine, graywacke

Position Backslopes, shoulders, summits

Slope shape Mostly convex

Ground surface features

Phase

A1 A2 B C1 C2 C3 D A + B

 (n = 11) (n = 1) (n = 12) (n = 3) (n = 13) (n = 2) (n = 2) range

Cover (%)

Bare ground 11 21 15 5 25 38 16 1–35

Bedrock 1 0 0 0 1 0 0 1–5

Rock 5 1 3 3 3 0 1 1–30

Gravel 8 37 8 8 10 34 26 1–40

Pavement 7 0 10 0 2 0 0 0–55

Mosses and 

 lichens 1 2 1 2 1 0 0 0–5

Litter 53 19 50 53 30 5 58
46

GENERAL TECHNICAL REPORT PNW-GTR-641

year after the fire in a phase A1. Phase B portrays a moderate stand of sagebrush where lack of fire and overgrazing 

have contributed to an increase in sagebrush and a decline in 

bunchgrasses. Phase C1 portrays the community where the 

lack of fire and overgrazing have contributed to a dominance 

by sagebrush over all other plants. In phase C2, overgrazing 

and trampling by livestock have reduced bunchgrasses and 

favored forbs and bare ground. Phase C3 portrays the postburn community (first year after the burn of a C1 community). Phase D is the same community the fifth year following 

the burn, after several new plants have gained dominance.

Management considerations—

Mountain big sagebrush is damaged by fires of late summer when soil moisture is low. Cool burns when soils are 

moist allow some sagebrush to survive. Bunchgrasses are 

stimulated by light and moderate burns. Severe burns in 

communities with dense sagebrush can do serious damage to Idaho fescue and allow colonization of the site by 

more disturbance-adapted species, such as western needlegrass. Sandberg’s bluegrass and needlegrasses increase with 

overgrazing. Forbs that increase in these communities from 

disturbances are yarrow, paintbrushes, tailcup lupine, and 

creamy buckwheat.

Relationship to other studies— 

Schlatterer (1972) described ARTRV/FEID and ARTRV/

AGSP in south-central Idaho, Hopkins (1979b) classified a 

big sagebrush/bunchgrass plant association in south-central 

Oregon that is similar to this type, Mueggler and Stewart 

(1980) described ARTRV/FEID and ARTRV/AGSP habitat 

types in Montana, Hall (1973) incorporated ARTRV/FEID 

and ARTRV/AGSP in the ARTRV/bunchgrass plant community type in the Blue Mountains, Hironaka et al. (1983) 

described the ARTRV/FEID habitat type for southern Idaho, 

and Johnson and Simon (1987) classified ARTRV/FEID in 

northeast Oregon. Johnson and Clausnitzer (1992) described 

this plant association for the Blue and Ochoco Mountains.

Principal species—

Phase

A1 A2 B C1 C2 C3 D A + B

Species Code (n = 11) (n = 1) (n = 12) (n = 3) (n = 13) (n = 2) (n = 2) range

Cover (%)/constancy (%) Cover (%)

Shrubs:

 mountain big sagebrush ARTRV 7/100 1/100 29/100 63/100 25/100 0 6/100 1–50

 gray rabbitbrush CHNA2 0 0 1/25 0 3/31 0 1/50 0–1

 green rabbitbrush CHVI8 1/82 0 3/67 3/33 12/69 10/50 0 0–15

 bitterbrush PUTR2 2/45 0 2/50 0 1/15 0 0 0–10

 mountain snowberry SYOR2 1/9 0 0 0 0 1/50 2/100 0–1

Grasses:

 bluebunch wheatgrass AGSP 18/73 5/100 11/92 7/100 7/85 5/100 6/100 0–40

 mountain brome BRCA5 2/27 5/100 0 2/100 2/15 5/50 7/100 0–5

 Idaho fescue FEID 24/100 7/100 29/100 25/100 12/96 3/100 1/100 3–60

 prairie junegrass KOCR 2/73 4/100 2/58 1/67 3/46 0 0 0–5

 Sandberg’s bluegrass POSA12 8/91 4/100 10/83 5/100 9/92 6/100 1/50 0–53

 bottlebrush squirreltail SIHY 1/64 0 2/33 1/33 3/38 2/100 0 0–5

 western needlegrass STOC2 1/27 1/100 3/8 0 6/15 3/50 15/100 0–3

Forbs:

 common yarrow ACMIL 5/91 1/100 2/92 2/67 2/85 4/100 1/100 0–30

 pale agoseris AGGL 1/18 0 0 0 1/15 1/100 1/100 0–1

 pussytoes ANTEN 6/55 2/100 1/42 1/100 1/38 0 0 0–15

 arrowleaf balsamroot BASA3 3/9 0 6/33 35/33 5/23 1/50 2/100 0–20

 paintbrushes CASTI2 3/18 1/100 1/17 10/100 10/31 1/50 1/50 0–3

 narrowleaf collomia COLI2 3/27 2/100 1/17 1/67 1/8 2/50 1/100 0–5

 hawksbeards CREPI 1/91 2/100 1/58 1/33 1/69 1/100 1/100 0–5

 fleabanes ERIGE2 3/91 3/100 2/58 0 2/69 1/100 1/100 0–5

 creamy buckwheat ERHE2 8/100 5/100 4/83 15/100 8/85 3/100 16/100 0–15

 wayside gromwell LIRU4 0 0 1/25 1/33 1/38 1/100 2/100 0–1

 lupines LUPIN 7/64 10/100 13/50 10/100 18/69 8/100 2/100 0–20

 wiry knotweed POMA9 1/18 1/100 0 0 1/8 3/100 2/100 0–1

 western groundsel SEIN2 1/27 1/100 3/58 10/33 3/62 15/50 0 0–5
47

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Mountain big sagebrush/bluebunch wheatgrass-Sandberg’s bluegrass plant community type

Artemisia tridentata var. vaseyana/Agropyron spicatum-Poa sandbergii

ARTRV/AGSP-POSA12 SD2918 N = 8

Distribution— 

Central and southern Blue Mountains; Ochoco Mountains.

Environmental features— 

This plant community type was found on basalt, rhyolite, 

and tuff. Elevations of sample plots ranged from 2,730 to 

5,290 ft (mean 4,564 ft). Slopes were gentle to steep (mean 

17 percent). Plots mainly on southerly aspects; on summits, 

shoulders, and backslopes; and on mostly convex surfaces. 

Brief soil investigations (n = 4) suggest shallow soils, with 

bedrock or very gravelly material within 6 in of the surface.

Vegetation composition— 

Mountain big sagebrush forms an open shrubland with 

bunchgrasses dominating beneath in the herbaceous layer. 

Green and gray rabbitbrushes are often associated. Severely 

browsed, decadent bitterbrush was present on several plots, 

as were juniper seedlings. Bluebunch wheatgrass is the most 

prominent bunchgrass. Sandberg’s bluegrass and bottlebrush 

squirreltail are associated. Forbs with high frequency are 

yarrow, creamy buckwheat, and hawksbeards. Idaho fescue 

is present only as an incidental species. Herbage production 

appears to be similar to the mountain big sagebrush/bunchgrass plant associations (mean 650 lb/ac; n = 2).

Capps Mountain, Emigrant Creek RD, Malheur NF.

Principal species—

Phase

C1 C2

Species Code (n = 1) (n = 7)

Cover (%)/constancy (%)

Shrubs: 

 mountain big sagebrush ARTRV 65/100 16/100

 gray rabbitbrush CHNA2 0 2/71

 green rabbitbrush CHVI8 1/100 5/51

 bitterbrush PUTR2 0 2/71

Grasses:

 bluebunch wheatgrass AGSP 20/100 17/100

 cheatgrass BRTE 0 9/43

 Idaho fescue FEID 0 2/57

 prairie junegrass KOCR 0 1/43

 Sandberg’s bluegrass POSA12 10/100 6/86

 bottlebrush squirreltail SIHY 0 6/43

Forbs:

 common yarrow ACMIL 1/100 1/43

 hawksbeard CREPI 1/100 1/43

 creamy buckwheat ERHE2 1/100 2/57

Mean Range

Elevation (feet) 4,564 2,730–5,290

Slope (percent) 17 1–45

Herbage (pounds/acre; n = 2) 650 450–850

Aspect (number of plots) NW (1), NE (1), SE (3), SW (3)

Lithology Basalt, rhyolite, tuff

Position Summit, shoulder, backslope, footslope

Slope shape Mostly convex

Ground surface features—

Phase

C1 C2

(n = 1) (n = 7)

Cover (%)

Bare ground 20 25

Bedrock 0 0

Rock 0 10

Gravel 10 10

Pavement 0 4

Mosses and lichens 1 3

Litter 69 58

States and transitions— 

Two phases were defined as follows:

C1 Sagebrush cover dense (>50 percent).

C2 Sagebrush cover less dense (<50 percent); 

bluebunch wheatgrass cover <25 percent; 

bare ground >20 percent.

Phase C1 portrays the community where overgrazing and 

lack of fire have contributed to a dominance by sagebrush 

over all other plants. In phase C2, overgrazing and trampling by ungulates have probably reduced grass cover and 

increased bare ground, but sagebrush has not expanded into 

the gaps. Droughty conditions on this type may hinder 

sagebrush expansion. The amount of wheatgrass cover that 

is possible under ideal conditions on this type is not yet 

known. It is possible that our phase C2 may represent a 
48

GENERAL TECHNICAL REPORT PNW-GTR-641

combination of site limitations (droughty soil) and only 

moderate degradation by grazing.

Management considerations—

 Mountain big sagebrush is damaged by fires of late summer when moisture is low in the soil. Cool burns when soils 

are moist allow some sagebrush to survive. Bunchgrasses 

are stimulated by light and moderate burns. With overgrazing, Sandberg’s bluegrass and needlegrasses are promoted. 

Forbs that increase in these communities from disturbances 

are yarrow, tailcup lupine, and creamy buckwheat.

Relationship to other studies— 

Schlatterer (1972) described ARTRV/AGSP in 

south-central Idaho, Hironaka et al. (1983) described 

an ARTRV/AGSP habitat type for southern Idaho, 

Mueggler and Stewart (1980) described an ARTRV/AGSP 

habitat type in Montana, and Hall (1973) incorporated 

ARTRV/AGSP in the ARTRV/bunchgrass plant 

community type in the Blue Mountains. This is the 

first description of the ARTRV/AGSP plant community 

type for the Blue and Ochoco Mountains.

Mountain big sagebrush-mountain snowberry/mountain brome plant community type

Artemisia tridentata var. vaseyana-Symphoricarpos oreophilus/Bromus carinatus

ARTRV-SYOR2/BRCA5 SD2917 N = 1

Mountain big sagebrush-mountain snowberry plant community type

Artemisia tridentata var. vaseyana-Symphoricarpos oreophilus

ARTRV-SYOR2 SD2919 N = 4

This plant community was found in the central and southern 

Blue Mountains and in the Ochoco Mountains, on granodiorite, rhyolite, volcanic sandstone, and chert. Elevations of 

sample plots ranged from 4,100 to 6,400 ft (mean 5,468 ft). 

Slopes were moderate to steep (mean 31 percent). Plots principally occurred on southerly aspects; on summits and backslopes; and on convex, straight, and undulating surfaces.

Mountain big sagebrush and mountain snowberry codominate an open shrubland. Bunchgrasses occurring with high 

frequency are Idaho fescue, mountain brome, bluebunch 

wheatgrass, and Sandberg’s bluegrass. Creamy buckwheat, 

western hawkweed, and Indian paintbrushes are always 

This plant community type was found in the northern Blue 

Mountains at 5,000 ft elevation on Columbia River basalts. 

It also occurs in the northern Wallowa Mountains (Johnson 

and Simon 1987). Mountain snowberry dominated mountain 

big snowberry. The herbaceous layer was composed of forbs 

that had increased owing to ungulate disturbance. Creamy 

buckwheat, lanceleaf stonecrop, and woodrush pussytoes 

were the dominant forbs. The prominent grass was mountain brome. Bluebunch wheatgrass was relict. These communities are adjacent to Douglas-fir/mountain snowberry 

forest on canyon shoulders adjacent to Idaho fescue-bluebunch wheatgrass grasslands.

found in the herbaceous layer. Other forbs frequently found 

are arrowleaf balsamroot, tailcup lupine, sticky cinquefoil, 

and Bolander’s yampah.

Sagebrush density increases with lack of periodic fire and 

with overgrazing. Mountain big sagebrush is damaged by 

fires of late summer when moisture is low in the soil. Cool 

burns when soils are moist allow some sagebrush to survive. 

Mountain snowberry resprouts vigorously after moderate 

burns. Bunchgrasses are stimulated by light and moderate 

burns. With overgrazing, Kentucky bluegrass and bulbous 

bluegrass invade. Green rabbitbrush also increases following severe grazing in these communities.
49

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Mountain big sagebrush/giant wildrye plant community type

Artemisia tridentata var. vaseyana/Elymus cinereus

ARTRV/ELCI2 SD3011 N = 1

Mountain big sagebrush/mountain brome plant community type

Artemisia tridentata var. vaseyana/Bromus carinatus

ARTRV/BRCA5 SS4914 N = 3

Mountain big sagebrush-squaw apple plant community type

Artemisia tridentata var. vaseyana/Peraphyllum ramosissimum

ARTRV-PERA4 SD3010 N = 1

Squaw apple occurs in plant associations with ponderosa 

pine in the central Blue Mountains (Johnson and Clausnitzer 1992) and with mountain snowberry in the southern Wallowa Mountains (Johnson and Simon 1987). The 

sagebrush-squaw apple plant communities occur on the 

northern edge of the Great Basin at the southern extreme 

of the Blue Mountains. This plot is on Moffit Table at 

4,500 ft elevation on Drinkwater basalt. Here mountain 

big sagebrush was codominant with squaw apple at 20 

percent cover each. Bitterbrush was also well represented 

(10 percent cover). Bunchgrasses were nicely represented 

by Idaho fescue, bluebunch wheatgrass, bottlebrush squirreltail, and Sandberg’s bluegrass. Spurred lupine was the 

most prominent forb.

This plant community was found on welded tuffs in the 

southern Blue Mountains. Mountain big sagebrush formed 

an open shrubland with giant wildrye, bluebunch wheatgrass, 

and Sandberg’s bluegrass. With severe overgrazing, these 

communities become weedy, with cheatgrass and western 

needlegrass increasing. Bluebunch wheatgrass and wildrye 

will both decline with overuse of these sites.

This plant community was found on basalts in the central 

and southern Blue Mountains, and in the Ochoco Mountains. Elevations of sample plots ranged from 5,090 to 6,800 

ft (mean 6,130 ft). Slopes were moderate (mean 17 percent). 

Aspects were southwesterly. Soils were loamy to gravelly 

loamy material over bedrock at a depth of 1 to 2 ft and had 

low water-holding capacity.

Mountain big sagebrush cover averaged 42 percent. 

Common snowberry was usually associated. The bunchgrass associated on deep soils between the shrubs is mountain brome. Tailcup lupine, western hawkweed, and creamy 

buckwheat are often associated with the brome. Western 

needlegrass can increase with ungulate disturbance.

Hironaka et al. (1983) described an ARTRV/BRCA5 

habitat type occurring between 7,000 and 9,500 ft elevation 

in southern Idaho.
50

GENERAL TECHNICAL REPORT PNW-GTR-641

Low sagebrush/Idaho fescue-bluebunch wheatgrass plant association

Artemisia arbuscula/Idaho fescue-Agropyron spicatum

ARAR8/FEID-AGSP SD1911 N = 21

Distribution— 

Central and southern Blue Mountains; Ochoco Mountains.

Benchmark site— 

Shaketable (proposed research natural area), Blue 

Mountain Ranger District, Malheur NF.

Environmental features— 

This plant association was found on basalt, andesite, 

rhyolite, and volcanic tuff. Elevations of sample plots ranged 

from 4,060 to 6,900 ft (mean 5,124 ft). Slopes were gentle 

(mean 5 percent). Plots occurred primarily on southerly 

slopes on mostly flat surfaces on summits, shoulders, and 

backslopes. Soils consisted of a loamy surface layer, 

sometimes gravelly to very gravelly, over a very to extremely gravelly clay loamy subsoil, with bedrock at 8 to 24 in. 

Soils are prone to perching (pooling) of excess water over 

the clayey subsoil in the spring, followed by depletion of 

soil water during the summer drought.

Vegetation composition— 

Low sagebrush shrubs occur with herbaceous vegetation 

dominated by bunchgrasses. Idaho fescue and Sandberg’s 

bluegrass are always present. Other prominent grasses are 

bluebunch wheatgrass, prairie junegrass, and bottlebrush 

squirreltail. Onespike oatgrass may occur as inclusions on 

thinner soils within the site. Bitterbrush frequently occurs 

as an incidental species (<5 percent cover). Common forbs 

found are phlox, fleabanes, yarrow, pussytoes, and serrate 

balsamroot.

States and transitions— 

Five phases were defined as follows:

A Idaho fescue and bluebunch wheatgrass cover 

total >35 percent.

B Idaho fescue and bluebunch wheatgrass cover total 

25 to 35 percent; bare ground cover <30 percent.

C Idaho fescue and bluebunch wheatgrass cover total 

<25 percent or bare ground cover >30 percent.

D1 Idaho fescue and bluebunch wheatgrass cover total 

≤5 percent; few annuals.

D2 Idaho fescue relict or absent; the annual grass Ventenata 

dubia dominates.

With overgrazing, phase A will shift toward phase B with 

diminished cover by Idaho fescue and bluebunch wheatgrass. As degradation of the bunchgrass community 

continues, phase C is reached where a high percentage of 

ground surface is nonvegetated. Phase D is attained when 

overgrazing reduces the deep-rooted bunchgrasses to a stage 

where restoration of Idaho fescue or bluebunch wheatgrass 

cannot result without intervention by managers. Idaho 

fescue is relict or absent in phase D2 and annuals dominate.

Management considerations— 

Fires are uncommon in ARAR8/FEID-AGSP communities because of low fuel levels. Low sagebrush plants are 

killed or severely damaged by fire, and the plant will not 

Shake Table, Blue Mountain RD, Malheur NF.

Mean Range

Elevation (feet) 5,124 4,060–6,900

Slope (percent) 5 1–15 (40)

Soil pH (n = 9) 6.2–7.6

Soil available water capacity 1.5–4 (very low to low)

 (inches, n = 7)

Depth to bedrock (inches, n = 16) 8–24

Herbage (pounds/acre, n = 18) 502 100–1,380

Aspect (number of plots) NW (5), NE (5), SE (4), SW (7)

Lithology Basalt, andesite, rhyolite, tuff

Position Summit, shoulder, backslope

Slope shape Mostly flat, convex

Ground surface features—

Phase

A B C D1 D2 A + B

(n = 5) (n = 7) (n = 5) (n = 3) (n = 1) range

Cover (%)

Bare ground 9 17 35 3 1 0–25

Bedrock 5 1 1 0 0 0–20

Rock 14 4 14 23 15 0–35

Gravel 0 2 3 7 0 0–5

Pavement 9 6 4 17 0 0–25

Mosses and lichens 3 1 0 2 2 0–10

Litter 55 43 23 25 80
51

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

sprout from the roots or stem base. Late summer and 

early fall burns may damage fescue when soils are dry. 

Burning at this time of the year promotes bluebunch 

wheatgrass and annuals. These communities are key habitats for sage grouse. Low sagebrush provides important 

browse for mule deer and pronghorns in spring and fall.

Relationship to other studies— 

Hall (1973) described ARAR8/FEID-AGSP as a low 

sagebrush/bunchgrass plant community type in the Blue 

and Ochoco Mountains. Volland (1976) described a low 

sagebrush/Idaho fescue plant community type for the 

national forests of central and south-central Oregon; 

Hopkins (1979a) described a low sagebrush/Idaho fescue-bottlebrush squirreltail plant community type for 

the Winema NF in south-central Oregon. In Montana, 

Mueggler and Stewart (1980) described ARAR8/FEID 

and ARAR8/AGSP habitat types. Hironaka et al. (1983) 

classified ARAR8/FEID as a habitat type in western 

Idaho. Johnson and Clausnitzer (1992) described the 

ARAR8/FEID-AGSP plant association for the Blue 

and Ochoco Mountains.

Principal species—

Phase

A B C D1 D2 A + B

Species Code (n = 5) (n = 7) (n = 5) (n = 3) (n = 1) range

Cover (%)/constancy (%) Cover (%)

Shrubs:

 low sagebrush ARAR8 21/100 29/100 30/100 23/100 40/100 11–50

 bitterbrush PUTR2 4/60 2/57 2/60 0 5/100 0–7

Grasses:

 bluebunch wheatgrass AGSP 16/80 13/43 3/80 1/67 5/100 0–25

 onespike oatgrass DAUN 5/20 1/29 1/40 6/67 0 0–5

 Idaho fescue FEID 28/100 24/100 15/100 3/100 1/100 8–40

 prairie junegrass KOCR 1/60 1/43 2/60 1/33 1/100 0–2

 Sandberg’s bluegrass POSA12 11/100 14/100 8/100 14/100 1/100 5–30

 bottlebrush squirreltail SIHY 1/40 2/57 4/80 1/33 0 0–1

Forbs:

 common yarrow ACMIL 1/60 2/71 1/60 1/67 1/100 0–3

 narrowleaf pussytoes ANST2 1/20 7/14 1/40 1/33 1/100 0–7

 sandworts ARENA 1/40 4/43 1/20 1/33 0 0–10

 serrate balsamroot BASE2 2/40 1/43 1/40 1/67 0 0–2

 hawksbeards CREPI 1/40 2/14 1/20 1/33 0 0–2

 fleabanes ERIGE2 3/60 1/43 2/20 0 0 0–3

 woolly goldenweed HALA3 1/20 1/43 2/40 1/33 0 0–1

 lupines LUPIN 1/40 2/29 10/20 0 0 0–2

 microseris MICRO6 2/40 2/29 1/40 1/33 0 0–3

 phloxes PHLOX 6/80 5/43 5/80 2/67 1/100 0–10 
52

GENERAL TECHNICAL REPORT PNW-GTR-641

Low sagebrush/bluebunch wheatgrass plant association

Artemisia arbuscula/Agropyron spicatum

ARAR8/AGSP SD1924 N = 8

Distribution— 

Ochoco Mountains.

Environmental features— 

This plant association was found on basalt and andesite. Elevations of sample plots ranged from 4,550 to 5,200 ft 

(mean 4,906 ft). Slopes were gentle (mean 7 percent). Plots 

occurred primarily on southwesterly slopes on mostly flat 

surfaces on summits, shoulders, backslopes, and footslopes. 

Soils consisted of a loamy surface layer, sometimes gravelly to very gravelly, over an extremely gravelly clay loamy 

subsoil, with bedrock at 8 to 18 in. Soils are prone to perching of excess water over the clayey subsoil in the spring, followed by depletion of soil water during the summer drought.

Vegetation composition— 

Low sagebrush shrubs occur with herbaceous vegetation dominated by bunchgrasses. Bluebunch wheatgrass 

and Sandberg’s bluegrass are always present. Idaho fescue is absent or incidental at low cover (<5 percent). Other common grasses are prairie junegrass, and bottlebrush 

squirreltail. Onespike oatgrass may occur as inclusions on 

thinner soils within the site. Bitterbrush frequently occurs 

as an incidental species (<5 percent cover). Forbs commonly found are yarrow, tapertip onion, low pussytoes, sulfurflower buckwheat, bighead clover, and lomatiums.

States and transitions— 

Three phases were defined as follows:

A Bluebunch wheatgrass cover >30 percent.

B Bluebunch wheatgrass cover 15 to 30 percent; 

bare ground usually <20 percent.

C Bluebunch wheatgrass cover <15 percent; 

bare ground usually >20 percent.

With overgrazing, phase A will shift toward phase B 

with diminished cover by wheatgrass. As degradation continues, wheatgrass declines toward 5 percent cover with an 

increase in bare ground (phase C).

Management considerations— 

Fires are uncommon in ARAR8/FEID-AGSP communities because of low fuel levels. Low sagebrush plants are 

killed or severely damaged by fire, and the plant will not 

sprout from the roots or stem base. These communities are 

key habitats for sage grouse. Low sagebrush provides important browse for mule deer and pronghorns in spring 

and fall.

Near Bald Butte, Emigrant Creek RD, Malheur NF.

Ground surface features—

Phase

A B C A + B

(n = 3) (n = 3) (n = 2) range

Cover (%)

Bare ground 13 16 25 9–24

Bedrock 2 15 9 2–16

Rock 12 9 21 4–19

Gravel 0 0 0 0

Pavement 9 4 6 3–12

Mosses and lichens 6 7 14 0–11

Litter 58 49 25 

Mean Range

Elevation (feet) 4,906 4,550–5,200

Slope (percent) 7 2–12

Soil pH (n = 8) 6.3–7.0

Soil available water capacity 1–2.5 (very low to low)

 (inches, n = 8)

Depth to bedrock (inches, n = 8) 8–18

Herbage (pounds/acre, n = 8) 423 330–520

Aspect (number of plots) NW (0), NE (1), SE (0), SW (7)

Lithology Basalt, andesite

Position Summit, shoulder, backslope, footslope

Slope shape Convex, flat

Fred Hall
53

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Principal species—

Phase

 A B C A + B

Species Code (n = 3) (n = 3) (n = 2) range

Cover (%)/constancy (%) Cover (%)

Shrubs:

 low sagebrush ARAR8 20/100 23/100 18/100 5–29

 bitterbrush PUTR2 2/67 3/100 5/50 0–4

Grasses:

 bluebunch wheatgrass AGSP 32/100 20/100 7/100 19–33

 onespike oatgrass DAUN 0 1/67 2/100 0–1

 Idaho fescue FEID 2/33 3/33 2/50 0–3

 prairie junegrass KOCR 1/100 1/67 0 0–1

 Sandberg’s bluegrass POSA12 9/100 7/100 6/100 5–12

 bottlebrush squirreltail SIHY 1/33 1/100 2/100 0–2

Forbs:

 common yarrow ACMIL 3/100 1/67 1/50 0–4

 pale agoseris AGGL 2/33 1/33 2/50 0–2

 tapertip onion ALAC4 2/67 1/100 2/50 0–2

 low pussytoes ANDI2 2/67 2/67 1/50 0–3

 scabland fleabane ERBL 1/33 1/33 1/50 0–1

 Sulfur–flower buckwheat ERUM 1/67 1/33 1/50 0–1

 lomatium LOMAT 4/100 1/33 4/100 0–7

 false agoseris MITR5 1/33 2/67 2/50 0–2

 phlox PHLOX 0 2/100 4/50 0–3

 Douglas’ campion SIDO 1/67 1/33 1/50 0–1

 bighead clover TRMA3 2/67 2/67 1/50 0–4

Relationship to other studies— 

In Montana, Mueggler and Stewart (1980) described an ARAR8/AGSP habitat type. Hironaka 

et al. (1983) described an ARAR8/AGSP habitat 

type in western Idaho. This is the first description 

of ARAR8/AGSP for the Ochoco Mountains.
54

GENERAL TECHNICAL REPORT PNW-GTR-641

Low sagebrush/Sandberg’s bluegrass plant association

Artemisia arbuscula/Poa sandbergii

ARAR8/POSA12 SD9221 N = 4

Distribution—

Southern Blue and Ochoco Mountains.

Environmental features— 

This plant association was found on basalt and andesite. Elevations of sample plots ranged from 4,520 to 6,950 ft 

(mean 5,455 ft). Slopes were gentle (mean 4 percent). Plots 

occurred primarily on southwesterly slopes on mostly flat 

surfaces on summits and shoulders. Brief soil investigations (n = 3) indicate shallow soils, with bedrock at a depth 

of about 10 in.

Vegetation composition—

Low sagebrush/Sandberg’s bluegrass shrublands are 

rocky sites with herbaceous vegetation in low cover. Bluebunch wheatgrass and Idaho fescue may be present with incidental cover (<5 percent). Sandberg’s bluegrass is always 

present as the dominant herbaceous plant. Other grasses 

commonly found are bottlebrush squirreltail and onespike 

oatgrass. Forbs of common occurrence are dwarf yellow 

fleabane, bighead clover, and sandworts.

States and transitions— 

Two phases were defined as follows:

AB Sandberg’s bluegrass cover >5 percent; 

bare ground <25 percent.

D Sandberg’s bluegrass cover <5 percent; 

bare ground >25 percent.

With overgrazing of phase AB, Sandberg’s bluegrass 

declines and is replaced by forbs and bare ground. As 

degradation continues (phase D), Sandberg’s bluegrass cover declines to negligible levels such that its regeneration 

would be difficult, and increase in bare ground leaves the 

soil vulnerable to erosion.

Aldrich Mountain, Blue Mountain RD, Malheur NF.

Mean Range

Elevation (feet) 5,455 4,520–6,950

Slope (percent) 4 1–8

Herbage (pounds/acre, n = 3) 158 100–250

Aspect (number of plots) NW (0), NE (0), SE (1), SW (3)

Lithology Basalt, andesite

Position Summit, shoulder

Slope shape Flat, convex

Principal species—

Phase

 A + B D A + B

Species Code (n = 3) (n = 1) range

Cover (%)/constancy (%) Cover (%)

Shrubs:

 low sagebrush ARAR8 12/100 3/100 5–20

Grasses: 

 bluebunch wheatgrass AGSP 2/33 1/100 0–2

 onespike oatgrass DAUN 1/33 1/100 0–1

 Idaho fescue FEID 2/67 0 0–3

 Sandberg’s bluegrass POSA12 10/100 1/100 6–15

 bottlebrush squirreltail SIHYH 5/67 3/100 0–8

Forbs: 

 sandworts ARENA 2/67 1/100 0–4

 dwarf yellow fleabane ERCH4 2/67 3/100 0–3

 phlox PHLOX 2/67 1/100 0–2

 bighead clover TRMA3 2/67 0 0–2

Ground surface features—

Phase

A + B D A + B

(n = 3) (n = 1) range

Cover (%)

Bare ground 13 30 5–20

Bedrock 2 0 0–3

Rock 50 30 30–60

Gravel 0 0 0

Pavement 15 25 0–40

Mosses and lichens 8 2 5–15

Litter 12 10

Fred Hall
55

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Management considerations— 

Fires rarely impact ARAR8/POSA12 communities because of the rocky site with scattered plant cover. These 

sites are affected most in spring when soils are saturated 

from snowmelt and bluegrass is heavily used by wild ungulates. Elk are key users of these sites when early spring 

provides only bluegrass for available forage. These communities are key habitats for sage grouse. Low sagebrush 

provides important browse for mule deer and pronghorns 

in spring and fall.

Relationship to other studies— 

Hopkins (1979a) described a low sagebrush/Sandberg’s 

bluegrass-onespike oatgrass plant community type on the 

Fremont NF in south-central Oregon that is esentially the 

same as this plant association. Hironaka et al. (1983) described ARAR8/POSA12 as a habitat type found in southern Idaho. This is the first description of ARAR8/POSA12 

for the Blue and Ochoco Mountains.

Stiff sagebrush/Sandberg’s bluegrass plant association

Artemisia rigida/Poa sandbergii

ARRI2/POSA12 SD9111 N = 30

Distribution— 

Northern, central, and southern Blue Mountains; 

Ochoco Mountains.

Environmental features— 

This plant association was found primarily on basalt and 

andesite, but also on tuff and rhyolite. Elevations of sample 

plots ranged from 4,000 to 5,550 ft (mean 4,729 ft). Slopes 

were gentle (mean 6 percent). Plots occurred on all aspects 

(primarily on southerly slopes) and mostly on flat surfaces of summits and shoulders. Soils consisted of a loamy 

surface layer a few in thick or absent, over gravelly to extremely clay loam, underlain by bedrock within 10 in of the 

surface. The water-holding capacity of these soils is very 

low.

Rocky Flat, Heppner RD, Umatilla NF.

Mean Range

Elevation (feet) 4,729 4,000–5,550

Slope (percent) 6 0–30

Soil pH (n = 21) 6.0–6.8

Soil available water capacity 0.5–1.5 (very low)

 (inches, n = 19)

Depth to bedrock (inches, n = 25) 3–9

Herbage (pounds/acre, n = 25) 176 80–303

Aspect (number of plots) NW (4), NE (2), SE (15), SW (9)

Lithology Basalt, andesite, tuff, rhyolite

Position Summit, shoulder, backslope

Slope shape Flat, convex

Ground surface features—

Phase

A B C A + B

(n = 10) (n = 15) (n = 5) range

Cover (%)

Bare ground 12 19 39 0–33

Bedrock 16 5 7 0–45

Rock 22 23 20 8–50

Gravel 2 7 2 0–25

Pavement 8 16 8 0–45

Mosses and lichens 7 9 8 0–20

Litter 10 9 1
56

GENERAL TECHNICAL REPORT PNW-GTR-641

Vegetation composition— 

Stiff sagebrush/Sandberg’s bluegrass shrublands occur 

on rocky sites where sagebrush is scattered over herbaceous vegetation at low cover levels. Sandberg’s bluegrass 

is always present as the dominant herbaceous plant. Bluebunch wheatgrass, bottlebrush squirreltail, and onespike 

oatgrass are commonly found growing with the bluegrass. 

Idaho fescue may be present at incidental cover (<5 percent). Forbs of common occurrence are tapertip onion, yarrow, low pussytoes, false agoseris, lanceleaf stonecrop, 

bighead clover, phloxes, and lomatiums. Herbage productivity is lowest of any shrubland type (mean 176 lb/ac).

Principal species—

Phase

A B C A + B

Species Code (n = 10) (n = 15) (n = 5) range

Cover (%)/constancy (%) Cover (%)

Shrubs:

 stiff sagebrush ARRI2 16/100 15/100 20/100 4–25

 low sagebrush ARAR8 2/20 1/13 3/20 0–4

Grasses:

 bluebunch wheatgrass AGSP 5/40 2/33 0 0–8

 onespike oatgrass DAUN 5/50 3/73 6/60 0–10

 Idaho fescue FEID 3/30 1/33 1/20 0–4

 Sandberg’s bluegrass POSA12 20/100 12/100 14/100 3–30

 dwarf squirreltail SIHYH 1/60 2/73 3/80 0–7

 needlegrasses STIPA 0 1/20 2/60 0–1

Forbs:

 common yarrow ACMIL 1/30 1/33 2/40 0–1

 tapertip onion ALAC4 2/40 2/33 8/40 0–3

 Tolm’s onion ALTO 1/10 3/27 3/40 0–6

 low pussytoes ANDI2 2/50 2/40 3/20 0–3

 narrowleaf pussytoes ANST2 1/20 0 6/40 0–1

 serrate balsamroot BASE2 4/20 2/13 2/40 0–7

 Indian paintbrushes CASTI2 2/30 2/20 1/40 0–3

 fleabanes ERIGE2 1/10 1/40 3/20 0–1

 lomatiums LOMAT 3/70 4/87 4/60 0–19

 false agoseris MITR5 2/80 2/60 1/80 0–3

 phloxes PHLOX 6/40 2/33 1/20 0–20

 lanceleaf stonecrop SELA 3/50 4/40 8/40 0–7

 bighead clover TRMA3 7/90 8/53 9/40 0–20

States and transitions— 

Three phases were defined as follows:

A Sum of cover of bunchgrasses, mosses, and lichens, 

minus bare ground, is >10 percent.

B Sum of cover of bunchgrasses, mosses, and lichens, 

minus bare ground, is between 0 and 10 percent.

C Sum of cover of bunchgrasses, mosses, and lichens, 

minus bare ground, is <0 percent.

With overgrazing, bunchgrasses decline and soil cryptogamic crusts are destroyed, exposing bare soil. If the process progresses far enough, there will be less herbaceous 

vegetative cover than exposed bare soil (phase C).

Management considerations— 

Fires are infrequent and light in ARRI2/POSA12 

communities owing to the rocky site with scattered 

plant cover. Deer and elk are key users of these sites 

in early spring when only bluegrass is available as 

green forage. Adverse impacts may occur at this time 

because soils are saturated from snowmelt: ungulate 

traffic results in trampling damage to the herbaceous 

plants and soils. Sagebrush is frequently hedged from 

winter use by mule deer. These communities are key 

habitats for sage grouse. When stiff sagebrush invades 

deeper soil sites, fire can be employed to eradicate it.

Relationship to other studies— 

Stiff sagebrush/Sandberg’s bluegrass has been 

described by many ecologists. Daubenmire (1942, 

1970) was first to classify and describe an ARRI2/

POSA12 habitat type in eastern Washington. Others 

that followed were Hall (1973) in the Blue Mountains, 

Hironaka et al. (1983) in central Idaho, Tisdale (1986) 

in the Snake River Canyon of central Idaho, Johnson 

and Simon (1987) in the Wallowa Mountains and 

canyons of northeastern Oregon, and Johnson and 

Clausnitzer (1992) in the Blue and Ochoco Mountains.
57

Bunchgrass Plant Communities of the Blue and Ochoco Mountains: A Guide for Managers

Stiff sagebrush/Gairdner’s penstemon plant community type

Artemisia rigida/Penstemon gairdneri

ARRI2/PEGA SD9141 N = 2

These communities occur on basalt rock in the southern 

Blue Mountains at elevations ranging from 5,400 to 5,900 ft 

elevation. Soils are very shallow, with bedrock just a few 

inches below the surface. Stiff sagebrush cover ranged from 

15 to 20 percent over a flat landscape where rock cover 

Threetip sagebrush/Sandberg’s bluegrass-onespike oatgrass plant community type

Artemisia tripartita/Poa sandbergii-Danthonia unispicata

ARTR4/POSA12-DAUN SD2401 N = 1

This community occurs on Miller Flat in the southern Blue 

Mountains. It is on andesite at 5,170 ft elevation. Rock and 

gravel dominated the ground surface (65 percent cover), 

with threetip sagebrush the most dominant plant (20 percent 

cover). Two shallow-rooted bunchgrasses, Sandberg’s bluegrass and onespike oatgrass, were the dominant herbaceous 

plants with a cover of 10 percent each. The only forbs with 

cover over 5 percent were lomatiums (L. nudicaule and L. 

macrocarpum). Sagebrush branches had been browsed by 

mule deer.

Mountain snowberry mounds plant community type

Symphoricarpus oreophilus

SYOR2 SM32 N = 1

This plant community type occurs in the northern Wallowa 

Mountains (Johnson and Simon 1987). It was found in the 

northern Blue Mountains at 4,800 ft elevation on mounds 

overlying Columbia River basalts. Mountain snowberry 

dominated over an herbaceous layer composed of forbs 

that had increased owing to ungulate disturbance. Creamy 

buckwheat formed large mats and sticky cinquefoil, slender 

cinquefoil, foothill daisy, and lupine were present with a 

“weedy” apperance. Bunchgrasses were relict. Present at 

low cover were mountain brome and prairie junegrass. 

Kentucky bluegrass had invaded. These communities are 

adjacent to Douglas-fir forest and intermediate to mounded/

scabland sites where Idaho fescue-prairie junegrass and 

stiff sagebrush/Sandberg’s bluegrass occur.

ranged from 50 to 80 percent. Bunchgrasses were scant 

with no cover greater than 5 percent. Sandberg’s bluegrass 

and bottlebrush squirreltail were present. Gairdner’s 

penstemon was the herbaceous plant with highest cover 

(mean 4 percent). Other forbs present were onions, scabland 

fleabane, sulfur-flower buckwheat, and Hood’s phlox.

Creeping Oregon grape/bluebunch wheatgrass-spreading dogbane plant community type

Berberis repens/Agropyron spicatum-Apocynum androsaemifolium

BERE/AGSP-APAN2 GB4915 N = 1

This community was found on a steep (65 percent), southwest-facing slope in the southern Blue Mountains. Calcareous argillite gravels dominated the site. Plants were sparse 

with only those deep-rooted species capable of anchoring 

in a shifting talus slope. Spreading dogbane is well adapted 

with rhizomatous roots for shifting gravel slopes. Creeping 

Oregon grape stabilizes the slope. Bluebunch wheatgrass 

was able to sink deep roots and to establish on the xeric, 

hot site. The most common forb was broom buckwheat—

a shifting slope dweller of reknown.