DEPAR TMENT OF AGRICULT URE

Rangeland Exclosures 

of Northeastern Oregon: 

Stories They Tell (1936–2004)

Charles Grier Johnson, Jr.

United States 

Department of 

Agriculture

Forest Service

Pacific Northwest 

Research Station

General Technical Report

PNW-GTR-724

August 2007
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Author

Charles Grier Johnson, Jr., was the Area Ecologist for the Malheur, Umatilla, 

and Wallowa-Whitman National Forests from 1978 until his retirement in 2005. His 

specialties included plant community classification of alpine and subalpine vegetation, rangeland vegetation, and postfire succession in forest and rangeland plant 

communities. This publication, as well as his numerous other publications on the 

ecology of the Blue Mountains and Hells Canyon, testify to his lifelong scientific 

interest in and love for the area.

Cover: The Allen Springs three-way exclosure, Wallowa Valley Ranger District, 

Wallowa-Whitman National Forest. The game exclosure is located in the centerleft, with the somewhat larger livestock exclosure behind it. The open (unfenced) 

monitoring plots are located in the foreground just out of view. 21 July 1978.
Abstract

Johnson, Charles Grier, Jr. 2007. Rangeland exclosures of northeastern Oregon: stories 

they tell (1936–2004). Gen. Tech. Rep. PNW-GTR-724. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station. 33 p.

Rangeland exclosures installed primarily in the 1960s, but with some from the 1940s, 

were resampled for changes in plant community structure and composition periodically 

from 1977 to 2004 on the Malheur, Umatilla, and Wallowa-Whitman National Forests in 

northeastern Oregon. They allow one to compare vegetation with all-ungulate exclusion 

(known historically as game exclosures), all-livestock exclusion (known historically as 

stock exclosures), and with no exclusion (known as open areas). Thirteen upland rangeland 

exclosures in northeastern Oregon were selected and are presented with plant community 

trend data and possible causes of changes over time. Key findings are that moderate 

grazing by native ungulates afforded by the livestock exclosures generally stimulated 

bunchgrasses to retain dominance and vitality; native bunchgrasses can replace invasive 

rhizomatous plants given a reduction in disturbance over time; shrubs increased without 

ungulate use in shrubland communities; and invasive annuals that established following 

severe disturbances to the grassland community diminished with aggressive competition 

from perennial bunchgrasses.

Keywords: Exclosure, northeastern Oregon, plant community, plant association, trend.

Charles Grier Johnson, Jr., 

1943–2007. 
The Grizzly Ridge three-way exclosure, Hells Canyon National Recreation Area, Wallowa-Whitman National Forest. The two 

light-colored squares are the livestock exclosure (the larger of the two) and the game exclosure (smaller and located below and to the 

left of the livestock exclosure). The open (unfenced) monitoring plots are located in the foreground between the camera and the game 

exclosure. 27 June 1977
Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Introduction

Rangeland and wildlife managers and natural resource scientists consider 

exclosures important tools for observing changes over time from lack of domestic 

ungulate use, wild ungulate use, usage by all ungulates including livestock, 

protection from other disturbances, and the natural climatic variation. Many 

exclosures were constructed in the 1960s with the idea that they would be 

maintained as long-term monitoring sites well past the span of a single 

generation of managers and scientists.

This paper synthesizes the results of multiple years of data collection, 

provides a selection of the findings from key exclosures located on the three 

national forests, and highlights the competitive relationships among plant 

species, the relations between plants and animals, and long-term succession. 

The majority of the interpretations result from comparative analysis of plant 

community data collected at different times. Some of the interpretations related 

to cause and effect of vegetation change at the exclosure locations are based on 

published literature coupled with the author’s observations over 30 years of plant 

ecology study. 

Rangeland Reference Areas

The sites where exclosures have remained with integrity over time are excellent 

rangeland reference areas. Exclosures preserve areas as baselines against which 

areas affected by management of the natural environment can be evaluated (Allen 

1986, Laycock 1975). These exclosures provide the land manager and rangeland 

scientist with the benchmarks for the potential vegetation that a site is capable of 

supporting in the absence of disturbances. They also give an indication of the vigor 

and vitality of the plants without grazing, with light to moderate grazing by wild 

ungulates, and with the effects from both wildlife and livestock grazing. These are 

areas set aside to illustrate and represent virgin conditions of forest or rangeland 

growth, as well as other conditions (grazed) that have special or unique characteristics of scientific interest and importance from a range resource standpoint, and 

are retained primarily for the purpose of science, research, and education (Laycock 

1975). They have become excellent demonstration areas for other rangeland and 

wildlife professionals, rangeland scientists, educators and their students, and the 

general public.

Exclosures preserve 

areas as baselines 

against which 

areas affected by 

management of the 

natural environment 

can be evaluated.
GENERAL TECHNICAL REPORT PNW-GTR-724

Early History of Exclosures on Rangelands of the 

Western United States

Rangeland managers and rangeland scientists have long used relict areas protected 

from grazing by natural barriers as well as constructed exclosures as baseline areas 

to compare with grazed areas. G.D. Pickford (1932) compared plant composition 

within and adjacent to exclosures in Utah. He noted a severe degradation of the 

perennial grasses, an increase of perennial forbs and annual grasses, a decline in 

overall plant density, and an increase in big sagebrush outside the exclosure. In 

central Montana a similar observation in 1948 demonstrated that Sandberg’s 

bluegrass, mountain big sagebrush, and gray rabbitbrush (see appendix for 

scientific names of species) were more abundant on grazed Idaho fescue 

communities than in the ungrazed exclosure (Evanko and Peterson 1955). 

Problems With Early Exclosures

Early exclosures were often constructed by wildlife biologists to collect browse 

information. The sampling of a cohesive plant community, or of key plants within 

the excluded area, was often not intended. Even when vegetation communities were 

sampled correctly, often permanent plots were not established outside the exclosure 

to quantify the vegetation of the community as a comparison with that on the inside 

(USDA FS 1965a). For example, sampling big game study plots in northeastern 

Oregon consisted of recording browse species and their composition by line intercept, readings of pellet groups along a belt transect, measurements of browse use 

on 10 shrubs, and photographing from internal camera points (USDA FS 1965b). 

These generally were not set up with permanent vegetation sampling transects for 

acquiring data about the plant community composition and its change over time.

Many early exclosures were too small with many not much larger than cages. 

Stoddart and Smith (1955), in their rangeland textbook, urged early rangeland 

conservationists to construct exclosures of at least 1⁄4 acre. The Forest Service and 

Bureau of Land Management subsequently required exclosures to be at least 1 acre 

(Laycock 1975). It was determined that although a three-strand cattle-proof fence 

had little influence on microclimate, woven wire fencing used to deter sheep would 

modify the microclimate inside for a distance of 10 times the fence height (USDA 

FS 1965a). Exclosures were also found to attract animals (birds perching and 

depositing seed in droppings along the edge, small mammals, and rodent populations increasing owing to increased herbage—both standing and as litter) (Laycock 

1975). 
Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Exclosure locations were haphazard at first. Common problems were the establishment of an exclosure straddling two different environments, or the sample plots 

being established on different environments within the exclosure versus outside the 

exclosure. Another key factor was the need to regularly maintain the exclosure to 

retain its integrity. The entry of a grazing animal into an exclosure built to analyze 

the plant community in the absence of grazing compromised the value of that exclusion to investigators and managers. 

Types of Exclosures

Three types of exclosures were used in this study. 

1. The one-way exclosure was installed to evaluate only the included plants 

and plant community. Many of the earliest exclosures were one-way and 

too small. 

2. The two-way exclosure was designed to compare the protected vegetation 

within the exclosure with the unprotected vegetation nearby. Sampling was 

conducted inside and outside the exclosure.

3. The three-way exclosure allowed for two kinds of protected areas and an 

unprotected area (plot). The all-ungulate-proof exclosure usually consisted 

of an 8- to 10-foot-high woven wire fence to exclude all large animals 

(ungulates) and was called the “game” exclosure. The livestock-proof exclosure usually consisted of a three-strand barbed-wire fence and was called 

the “stock” exclosure. The third area was unprotected and was called the 

“open” plot where effects of dual usage could be sampled. 

Three-way exclosures have provided the most valuable information over time. 

They allow for the separation of the effects from combined usage (open plot), wild 

ungulates (livestock exclosure), and total grazing and browsing exclusion (game 

exclosure). The data can then be analyzed for the effects of specific use on plant 

composition, palatability, and trend. Other uses are the evaluation of annual fluctuations in herbage production owing to climate effects (game exclosure) and the speed 

of recovery as determined by vegetation sampling for trend (game and livestock 

exclosures). 

Stagnation in Three-Way Exclosures

Stagnation is defined as the accumulation of dead biomass including litter as well 

as standing dead plant material in the absence of fire or grazing. This multiyear 

accumulation provides cover that attracts rodents (especially mice and voles). 

Without grazing or fire these communities of range plants deteriorate and stagnate 

Three-way exclosures 

have provided the most 

valuable information 

over time.
GENERAL TECHNICAL REPORT PNW-GTR-724

from a reduction in productivity (Anderson et al. 1970, Tueller and Tower 1979). 

The increase in mice and voles leads to small areas with increased soil disturbance 

resulting from burrowing and foraging activities. The ground disturbance by 

rodents can lead to invasive plants. In fescue-dominated communities, Kentucky 

bluegrass (Poa pratensis) capitalizes on the disturbance event to dominate microsites. Barring cessation of the rodent infestation and lack of fire, the vegetation 

reverts to an earlier sere. Livestock exclosures have repeatedly been associated with 

the healthiest grassland vegetation over time with the plant community nearing 

potential in response to periodic grazing by wild ungulates (especially elk [Cervus 

canadensis]). 

Where shrubs are a component in the protected plant communities, those 

shrubs within the game exclosures produced the least forage (Garrison 1953). For 

example, sampling at four exclosures in Nevada showed stagnation of antelope 

bitterbrush and mountain big sagebrush as early as 2 years after establishment of 

the game exclosures (Tueller and Tower 1979). This release from shrubs led to an 

increase in grass and forb production from the available nutrients and moisture. 

However, the increase in grass production within the game exclosure contained 

grasses with a higher percentage of dead material and a decline in thrift. This was 

not the case with the grasses of the livestock exclosure where grazing wild animals 

provided an annual stimulus to grasses.

Exclosures of Northeastern Oregon

For a complete listing of the exclosures with locations, dates of establishment, sizes, 

and plant communities, see appendix 3.

Exclosures of the Wallowa-Whitman National Forest

The Wallowa-Whitman National Forest contains 12 exclosures. Eleven are threeway exclosures constructed by Wade B. Hall, Forest range staff officer, between 

1962 and 1969. The only one-way exclosure on the Wallowa-Whitman National 

Forest is at Bald Mountain on the Baker Ranger District of the Whitman Unit. It is 

the oldest, was built with logs in the 1940s, and encloses forest vegetation. The geographic coverage of the 1960s-era three-way exclosures provides a comprehensive 

sample of the key vegetation of the rangelands on both sides of the Wallowa Mountains and in the Blue Mountains of the Wallowa-Whitman National Forest. There 

are five exclosures in Hells Canyon National Recreation Area, one on Wallowa 

Valley Ranger District, and one in the Eagle Cap Ranger District on the north side 

of the Wallowa Mountains. Two exclosure sites are on the south side of the Wallowa 
Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Mountains (on Pine Ranger District of the Whitman Unit). The final two sites are 

in the Blue Mountains on Baker and Unity Ranger Districts of the Whitman Unit.

Ridgetop Exclosures in Bunchgrasses

In 1963, the first three-way exclosure was constructed north of Allen Springs on a 

bunchgrass-dominated ridgetop overlooking Joseph Creek Canyon. In 1969, four 

more three-way exclosures were built on bunchgrass-dominated ridgetops running 

north to south from the Imnaha River canyon crest to the Snake River canyon crest. 

The elevations of the five sites were 4,600 feet (Allen Springs), 5,100 feet (Grizzly 

Ridge), 5,300 feet (Coffeepot), 5,500 feet (Lord Flat), and 5,900 feet (Mormon Flat). 

All sites are dominated by bunchgrass plant communities of the Idaho fescueprairie junegrass (Festuca idahoensis-Koeleria cristata) plant association (Johnson 

and Simon 1987). 

The game exclosures enclosed approximately 1 acre. The livestock exclosures 

differed but generally enclosed 3 acres. Two or three line transects were installed 

at the time of establishment within the exclosures and at an adjacent open area at 

each site.

These transects were initially sampled by using the 3⁄4-inch loop technique 

(Parker 1951) to determine percentage composition by species. Subsequent 

sampling was performed by using a square-foot quadrat to acquire percentage 

composition by species (Daubenmire 1959). Only the multiple samples taken by 

the quadrat technique are compared arithmetically. There is no arithmetic 

comparison made between the two techniques. 

The initial sample data are valuable as they provide the baseline information 

of the ecological condition at the time of exclusion. The subsequent comparison of 

data derived from the quadrat indicates the successional trend for the vegetation 

over time from the start of quadrat sampling.

Allen Springs Three-Way Exclosures (Established 1963)

In 1986, the Joseph-Starvation Fire burned with moderate severity through the plant 

communities of both exclosures on Allen Springs Ridge. The vegetation along the 

permanent monitoring transects was resampled the first growing season after the 

burn and subsequently at approximate 5-year intervals. 

In the first 5 years after the burn, Idaho fescue increased in cover from 12 

percent in 1987 to 21 percent in 1992 within the game exclosure (table 1). In the 

livestock exclosure, Idaho fescue declined initially from 17 percent in 1987 to 13 

percent in 1992 (owing to the attraction of the succulent fescue plants for elk and 

deer [Odocoileus spp.] following the burn). Bluebunch wheatgrass showed a similar 
Table 1—Vegetation trends of Wallowa-Whitman three-way exclosures 

Idaho fescue–prairie junegrass plant association p

Allen Springs Grizzly Ridge Coffee Pot Lord Flat Mormon Flat 

1977–2003 1977–2002 1971–2003 1977–2003 1971–2003 

G S Oa G S O G S O G S O G S O 

Perennial grasses:

Idaho fescue ↑ ↑ ↓ ↓ ↓ ↑ ↑ ↑ → ↑ ↑ ↑ ↑ ↑

Bluebunch wheatgrass ↓ → ↓ → ↓ → ↓ → → → ↓ 

Sandberg’s bluegrass → ↑ → ↑ → ↓ ↓

Kentucky bluegrass ↓ ↓ ↓ ↓ ↓ ↓ ↓ → ↑ 

Prairie junegrass → → → → → → → → → → → → →

Western needlegrass → → ↑Mountain brome → ↓ ↓ → → →

Onespike oatgrass ↓ ↓ ↑ ↓ ↓

Shrubs:

Common snowberry Rose 

Perennial forbs:

Yarrow → → → → → ↑ → → ↓ ↓ → → ↑ 

Creamy buckwheat → → ↑ → → ↑ ↑

Red avens → ↓ ↑ ↑ ↑ ↑

Lupines ↑ → → ↓ ↓ ↓ 

Sticky geranium ↑ ↑ →Slender cinquefoil ↓ ↓ ↓

Surface features:

Bare ground ↓ ↓ → → → ↑ → ↑ → → ↑ ↑ ↑ → Litter ↑ ↑ ↑ ↑ ↑ → ↑ → → → → ↓ ↑ ↑ 

Moss ↓ ↓ ↓ ↓ ↓ → ↓ 0 0 0 0 ↓ → 0 

Note:G = game exclosure, S = livestock exclosure, O = open sampling area, ↑ = upward trend, ↓ = downward trend, → = static trend, 0 = not present.a = Open area is on a different environment (site) than the exclosure sites. Data were not comparable.
Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

trend in the first 5 years by increasing in the game exclosure while declining in the 

livestock exclosure. More than 15 years after the burn, however, these bunchgrasses 

now co-dominate the grasslands within the livestock exclosure. Within the game 

exclosure, Idaho fescue now dominates over bluebunch wheatgrass 34 to 9 percent. Following the burn, prairie junegrass increased slightly and then returned to 

preburn levels of approximately 3 to 5 percent. 

Sandberg’s bluegrass (Poa secunda) was only present at 1 percent cover in the 

game exclosure historically but has exhibited increases in the livestock exclosure 

attributed to ungulate trampling and resulting microsite disturbance. After the 

burn, Sandberg’s bluegrass increased from 5 to 9 percent. This shallow-rooted 

bunchgrass is an opportunist when disturbance results from trampling of interstitial 

areas and when fire reduces coverage by the dominating deeper rooted bunchgrasses. 

Kentucky bluegrass became established in the game exclosure from a 1976–77 

rodent infestation. This is considered to be a direct result of total exclusion from 

foliar removal (fire, ungulates) within the game exclosure and exclusion of rodent 

predators. As a result, litter accumulated affording cover for mice and voles to create bunchgrass mortality in patches.

The first year following the 1986 fire, there was a dramatic increase from 7 to 

21 percent in Kentucky bluegrass in the game exclosure. Like the prairie junegrass, 

Kentucky bluegrass has now reverted to subordinate status within the bunchgrassdominated community with a cover of 4 percent.

Litter has markedly increased in the game exclosure reaching a high of 75 

percent of the amount before the 1986 burn. It was partially consumed by the fire 

and has now accumulated to a surface cover of 85 percent. In marked contrast, litter 

within the livestock exclosure covered 25 percent of the surface before the burn, 

dropped to 16 percent after the fire, and has increased to 55 percent. The amount 

of litter within the livestock exclosure is directly related to fluctuations in foliar 

growth owing to climatic conditions and to use by wild ungulates.

Grizzly Ridge Three-Way Exclosures (Established 1969)

The ridgetop site of the Grizzly Ridge exclosures had been severely overgrazed 

when the exclosures were installed in 1969 (table 1, fig. 1). The dominant bunchgrass then was Sandberg’s bluegrass, with a strong associate—onespike oatgrass 

(Danthonia unispicata). These shallow-rooted bunchgrasses are found commonly 

on scabland sites where soil is less than 10 inches deep to bedrock. However, when 

deeper soil sites that historically carry the deeper-rooted bunchgrasses are depleted, 
GENERAL TECHNICAL REPORT PNW-GTR-724

the shorter bunchgrasses often increase and invade to occupy these sites. Soils here 

ranged from 12 to 21 inches in depth.

In 1971, shortly after the exclosures were installed, Idaho fescue was found on 

all three sampling sites (within the game and livestock exclosures as well as in the 

open area). By 1981, Idaho fescue was completely absent from the open sampling 

area. Onespike oatgrass had established from the excluded areas to occupy the 

open site with a dominant 28 percent cover. Idaho fescue had not fared well in 

the exclosures either. In 1977, both Idaho fescue and bluebunch wheatgrass made 

up a combined cover of 35 percent in the game exclosure. By 2002, the cover of 

both within the two exclosures was down to only 16 percent; Idaho fescue was at a 

precarious cover of less than 5 percent. The loss of fescue, the decline in bluebunch 

wheatgrass, and the increase in onespike oatgrass can be attributed to fire and 

drought in both exclosures and to a combination of drought and grazing pressure by 

wild and domestic ungulates in the livestock exclosure and in the open area.

Figure 1—The Grizzly Ridge game exclosure, Hells Canyon National Recreation Area, Wallowa-Whitman National Forest. 21 July 1980.
Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

In 2001, the Horse Creek Fire burned through the Grizzly Ridge exclosures 

site. It burned moderately resulting in a dramatic increase by Sandberg’s bluegrass 

the year following the burn. Prior to the burn, the bluegrass was only minimally 

present in both exclosures at less than 3 percent cover. In 2002, Sandberg’s bluegrass covered 13 percent within the game exclosure and 18 percent in the livestock 

exclosure. Mosses and lichens had dramatically declined by 2002. They historically 

occupied coverages of 35 to 55 percent in the exclosures, but in 2002, they constituted less than 5 percent cover in the exclosures. The loss of bunchgrass canopy, 

subsequent drying and heating of the microsite, and direct heat from the wildfire 

is suspected to have caused the high mortality.

Coffeepot Three-Way Exclosures (Established 1969)

The exclosure is characterized by a dramatic increase in Idaho fescue (figs. 2a 

and 2b). In 1971, Idaho fescue did not occur within the two exclosures. Kentucky 

bluegrass completely dominated the game exclosure. It was less prominent in the 

livestock exclosure where bluebunch wheatgrass and Sandberg’s bluegrass were 

the dominant plants. In the open area, Kentucky bluegrass was the dominant grass. 

By 2003, Idaho fescue had replaced Kentucky bluegrass in the game exclosure as 

the dominant grass with a cover of 32 percent. In the livestock exclosure, Idaho 

fescue also had overtaken the other bunchgrasses with a cover of 20 percent. The 

story was the same in the open area where Idaho fescue dramatically increased 

to a cover of 18 percent with a resultant decline by Kentucky bluegrass to only 10 

percent. The probable increase in fescue at the expense of bluegrass and wheatgrass 

can be attributed to natural succession with decreased ungulate impacts inside 

the two exclosures. The reversal of dominance from Kentucky bluegrass to Idaho 

fescue in the open area can be a result of less grazing impact by livestock over 

the 30-year period with preferential grazing of the bluegrass by elk. Other notable 

bunchgrass trends were that western needlegrass had invaded since establishment 

of the exclosures but was present in the exclosures at coverages less than 5 percent 

in 2003. However, it occurred at 7 percent in the more heavily grazed open area. 

Prairie junegrass was static throughout the 1971–2003 period on all sites. 

Mormon Flat Three-Way Exclosures (Established 1969)

In the game exclosure, Idaho fescue doubled in cover to 13 percent with declines 

by Kentucky bluegrass, Sandberg’s bluegrass, and the loss of onespike oatgrass. In 

1971, Sandberg’s bluegrass dominated (41 percent cover) with onespike oatgrass 

strongly associated (9 percent cover). The exclusion and time (32 years) have given 

the competitive advantage to the fescue over the others. In the livestock exclosure, 

The probable increase 

in fescue at the 

expense of bluegrass 

and wheatgrass can 

be attributed to natural 

succession with 

decreased ungulate 

impacts inside the 

two exclosures. 
10

GENERAL TECHNICAL REPORT PNW-GTR-724

Figure 2a—The Coffee Pot game exclosure, Hells Canyon National Recreation Area, Wallowa-Whitman National Forest. The livestock 

exclosure is also partially visible at the top of the photograph. 27 June 1977.

Idaho fescue was co-dominant with Sandberg’s bluegrass and onespike oatgrass in 

1971. By 2003, Idaho fescue had dramatically increased to dominate at a cover of 

26 percent. Both of the other shallow-rooted bunchgrasses were less than 5 percent 

cover by 2003 with the strong increase by fescue. Idaho fescue also nearly doubled 

in cover in the open area (11 percent in 1971, 19 percent in 2003). However, Kentucky bluegrass, common yarrow (Achillea millefolium var. lanulosa), and red avens 

(Geum triflorum) all made dramatic increases over the 22-year period. Although 

cattle use ceased in 1979, elk numbers steadily increased through the mid 1980s. 

The resultant bluegrass-forb-dominated open site can be attributed to the long-term 

grazing effects as well as the more recent grazing impacts by elk. Mormon Flat 

had long-term domestic sheep use prior to the construction of the exclosures and 

has had heavy use by herds of elk. Mountain brome (Bromus carinatus) and prairie 

junegrass have remained static throughout the sampling period on all sites here.
11

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Figure 2b—The Coffee Pot livestock exclosure, Hells Canyon National Recreation Area, Wallowa-Whitman National Forest. 27 June 1977.

Lord Flat 3-Way Exclosures (Established 1969)

This is the one site that has been heavily modified from its presettlement state. The 

nearby Dorrance Ranch used the large flat for summer grazing of domestic sheep 

early after homesteading. Later, domestic cattle used the flat in summers until 1979. 

The site of the exclosures was apparently plowed and hayed for a number of years. 

The story the exclosures tell is one of secondary succession in the absence of total 

ungulate use over time in the game exclosure and of native ungulate use in the 

livestock exclosure. 

In 1969, Kentucky bluegrass dominated the “old field” of the flat. Idaho fescue 

was either absent (game exclosure) or with less than 5 percent cover (livestock 

exclosure and open area). Over the 34 years since construction of the exclosures, 

major changes have occurred. The game exclosure has become forb-rich with 

dominance in 2003 by red avens (17 percent cover), sticky geranium (Geranium 

viscosissimum) with a cover of 26 percent, and creamy buckwheat (Eriogonum 
12

GENERAL TECHNICAL REPORT PNW-GTR-724

heracleoides) (10 percent cover). Kentucky bluegrass is still the dominant grass 

(22 percent) with Idaho fescue only weakly present at 1 percent cover (table 1).

In the livestock exclosure, native ungulate use has allowed Idaho fescue to 

out-compete Kentucky bluegrass to attain co-dominance on the site. In 1977, 

Kentucky bluegrass cover was 65 percent. However, forbs are still the overwhelming dominant plants on the “old field.” Since 1977, geranium has quadrupled to 24 

percent cover. Other forbs have declined over the period but still have double-digit 

coverages (slender cinquefoil [Potentilla gracilis] 14 percent; red avens 18 percent). 

The open area is still dominated by Kentucky bluegrass (23 percent cover), but 

forbs are collectively the most dominant plants on the site. Since 1977, Idaho fescue 

has tripled to 15 percent cover while Kentucky bluegrass cover has declined from 

53 to 23 percent. The most dominant increasing forb is red avens. Slender cinquefoil is also prominent (12 percent cover).

Pleasant Valley Three-Way Exclosures (Established 1969)

In 1969, a three-way exclosure was constructed on the Snake River bench in 

Pleasant Valley (table 2, fig. 3). The relatively flat bench is located at a mid-canyon 

level (2,530 feet elevation) approximately 1,500 feet above the river. The Pittsburg 

Ranch was located on the river near Pleasant Valley Creek. Domestic sheep heavily 

used the bench over many grazing seasons prior to the 1969 establishment of the 

exclosures. In the later years prior to cessation of livestock use on the allotment, 

Lem Wilson converted to cattle. As with the rest of the Snake-Imnaha range, elk 

were a presence in Pleasant Valley, peaking in 1986. The ideal habitat of the grassdominated bench and an adjacent forested north slope beside the creek allowed a 

herd of elk to take up residency surrounding the exclosure sites.

Table 2—Pleasant Valley three-way exclosures

Game exclosure Livestock exclosure Open

Species 1983 1996 2002 1983 1996 2002 1983 1996 2002

Percent cover

Kentucky bluegrass 0 0 0 43 32 0 29 31 3

Bluebunch wheatgrass 0 6 5 2 18 52 2 16 42

Rose 10 13 18 1 1 4 2 1 7

Common snowberry 59 31 36 0 0 0 1 2 5

Common yarrow 0 3 0 5 1 0 7 3 2

Silky lupine 3 12 5 11 5 10 0 5 16

Arrowleaf balsamroot 0 7 12 1 0 0 0 0 0

Bare ground 4 0 0 0 1 1 1 0 1

Litter 93 95 99 86 98 98 90 96 95
13

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Unfortunately the three sites selected are not readily comparable. The game 

exclosure is located with one side adjacent to a gulch where shrubs persist. Since 

construction in 1969, a common snowberry-rose stand has increasingly invaded 

the grassland of the interior that was co-dominated by Kentucky bluegrass and 

bluebunch wheatgrass. The livestock exclosure is a distance up the sloping bench, 

and in 1969 there was no snowberry or rose component. This was not due to a site 

difference per se. The open area was, however, offsite on a rocky promontory where 

bluebunch wheatgrass was dominant over Sandberg’s bluegrass. 

The vegetation on the sites of the two exclosures is the common snowberry-rose 

(Symphoricarpos albus-Rosa spp.) plant association (Johnson and Simon 1987). 

Over the sampling history from 1971 to 2002, the rose component that initially 

dominated within the game exclosure has declined as snowberry increased its 

occupancy. However, both shrub species dominate together over the herbaceous 

component. Visually, as revealed in photographs, the shrub migration from south to 

Figure 3—The Pleasant Valley three-way exclosure, Hells Canyon National Recreation Area, Wallowa-Whitman National Forest. The 

game exclosure (center) has been strongly colonized by shrubs. The livestock exclosure is faintly visible above the game exclosure. The 

open (unfenced) monitoring plots are located near the edge of the photograph to the right of the game exclosure. 14 June 1983.
14

GENERAL TECHNICAL REPORT PNW-GTR-724

north within the game exclosure has been dramatic over this time. The shrubs have 

overtaken the grasslands–once having bluebunch wheatgrass and Kentucky bluegrass as co-dominants (figs. 4a and 4b). In 2002, only 5 percent cover remained of 

the wheatgrass, and Kentucky bluegrass had been eliminated altogether. Arrowleaf 

balsamroot (Balsamorhiza sagittata), initially absent in the game exclosure, was 

present in 1996 at 7 percent cover and continued increasing with a cover of 12 

percent in 2002 (table 1).

In the livestock exclosure, as with the game exclosure, bluebunch wheatgrass 

and Kentucky bluegrass initially co-dominated at the time of construction. By 

2002, bluebunch wheatgrass had become totally dominant within the exclosure 

as Kentucky bluegrass was eliminated. The probable causes for the changes are 

drought favoring the wheatgrass, elk preference for the bluegrass early in the season 

when it is most vulnerable, persistent standing litter in bluebunch wheatgrass 

reducing its palatability, and an overall lessening of grazing use resulting from the 

exclusion of domestic livestock. Another sign that grazing pressure has lessened is 

the slow increase by shrub seedlings within the exclosure.

The 1971 open sample area was offsite and therefore unusable as a comparison with the two exclosure sites. Therefore in 1983, line transects were installed 

between the two exclosures in an area of the same snowberry-rose plant association. In 1983, the site was almost totally dominated by Kentucky bluegrass (29 

percent cover) with only 2 percent cover by bluebunch wheatgrass. Snowberry and 

rose existed as strongly hedged plants well beneath the grasses at only 3 percent 

combined cover. This site looked like a well-mown lawn at the time of livestock 

use. By 2002, livestock use had ceased. The two grasses reversed dominance with 

Kentucky bluegrass now only 3 percent coverage on the site. Bluebunch wheatgrass 

increased occupancy from 2 percent to a dramatic 42 percent over the 19-year span 

of time. The shrubs were now making an emergence as well. The combined cover 

of snowberry and rose was 12 percent in 2002. In summation, the story told by the 

Pleasant Valley sampling over the past 31 years demonstrates the effects of grazing 

and browsing animals on plant succession and how severe use can maintain dominance by herbaceous vegetation that would otherwise be shrub dominated.

The effects of fire at Pleasant Valley—

The Pleasant Valley exclosure site burned twice over the past 31 years, in 1985 (a 

hunter-caused fire) and 1996 (Salt Creek Burn). The vegetation within the game 

exclosure burned with moderate severity in both fire events. Within the livestock 

exclosure, the plant communities were lightly burned by both fires. After the fires, 

the sites were visited to determine the extent and severity of the burn on the vegetation along the transects within each sample area. Then the first year after the fires 

The Pleasant Valley 

sampling demonstrates 

how severe use can 

maintain dominance by 

herbaceous vegetation 

that would otherwise 

be shrub dominated.
15

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Figue 4b—The Pleasant Valley three-way exclosure on 6 June 1996. The vegetation is now dominated by rose 

and snowberry shrubs.

Figure 4a—The Pleasant Valley three-way exclosure on 18 June 1976. Vegetation in this portion of the 

exclosure was dominated by bluebunch wheatgrass. The abundant white flowers are yarrow.
16

GENERAL TECHNICAL REPORT PNW-GTR-724

(1986, 1997), the vegetation was sampled at the culmination of annual growth. 

Thus fire succession was determined for the snowberry-rose plant association at the 

Pleasant Valley site, as sampling has been performed every 5 years following the 

initial resample after the burn year. 

In the game exclosure, the moderate burns reduced the canopy cover initially 

and also promoted rose over snowberry (1985: snowberry 4 percent, rose 16 percent). Five years later, snowberry had regained its preburn dominance over rose and 

maintained it following the 1996 burn as well. The first year after the burns, annuals capitalizing on the abundance of sunlight and growing space were the dominant 

plants within the game exclosure. Thymeleaf sandwort (Arenaria serpyllifolia) and 

yellow salsify (Tragopogon dubius) totaled 50 percent cover. By the fifth year, the 

sandwort was present only as a trace and salsify was absent. Annual bromes also 

capitalized on the fire event with increases of over 10 percent from preburn levels 

of only 2 percent. The bromes were absent by the 10th year, returned to 5 percent 

cover after the 1996 fire, and were absent by 2002. Increasing annual forbs of note 

were chervil (Anthriscus scandicina) and bedstraws (Galium aparine, G. trifidum) 

after both fires. These continue to be present at 15 percent cover each.

In the livestock exclosure, the two burns did not negatively influence the 

Kentucky bluegrass. It had coverage of 43 percent prior to the 1985 burn, was 31 

percent in 1986 after the first burn, 32 percent before the 1996 burn, and 29 percent 

in 1997 after the second burn. In the 5 years following, Kentucky bluegrass was 

replaced by bluebunch wheatgrass. As in the game exclosure, annuals were dominant in cover the first year after the burns. Thymeleaf sandwort and annual bromes 

were abundant. Small bedstraw (Galium trifidum) was especially prominent after 

the 1985 fire and continued with high cover (59 percent) after the 1997 burn. 

In the open area where Kentucky bluegrass had so thoroughly dominated owing 

to ungulate repression of the shrubs and bunchgrasses, bluegrass was unaffected by 

the fire in 1996. The dramatic change in 1997 was the emergence of a new annual 

grass species. Ventenata (V. dubia) emerged with a cover of 22 percent to occupy 

the charred ground surface, with bedstraw at 30 percent cover. Five years later in 

2002, the bedstraw was even more prolific (56 percent cover) replacing ventenata, 

which was totally absent from the site. 

In summation, the fires did little to deter the Kentucky bluegrass dominance in 

the livestock exclosure and the open sample area, but natural succession through 

reduced grazing pressure did deter it. The well-known fact that populations of 

annual vegetation can provide a showy dominance one year following enhanced 

growing conditions is often followed by the same dramatic change when they 

become a minor component the next year.

The fires did little to 

deter the Kentucky 

bluegrass dominance 

in the livestock 

exclosure and the 

open sample area, but 

natural succession 

through reduced 

grazing pressure 

did deter it.
17

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Exclosures of the Umatilla National Forest

The oldest exclosure existing today on the Umatilla National Forest is the Skookum 

three-way exclosure established in 1945 on the Heppner Ranger District. The forest 

contains seven existing exclosures (three three-way; one two-way; and three oneway). Two of the one-way exclosures are in forested plant communities on the Walla 

Walla Ranger District.

Skookum Three-Way Exclosures (Established 1945)

The Swale Creek Allotment on the southern end of the Heppner Ranger District 

has had a long history of grazing use and abuse. Permitted sheep use initiated in 

1922. Before 1935, a high number of sheep grazed over a 4-month season coupled 

with many deer, elk, and trespass livestock. After 1935, the Forest Service reduced 

numbers of permitted livestock with shortened grazing seasons in 1940 and 1952. 

In 1962, the allotment was converted to cattle use.

In 1945, three 2-acre sites were selected in communities of the western juniper/bitterbrush/Idaho fescue-bluebunch wheatgrass plant association (Juniperus 

occidentalis/Purshia tridentata/Festuca idahoensis-Agropyron spicatum) (Johnson 

and Clausnitzer 1992) for a three-way exclosure on a gentle ridge near Skookum 

Spring. In 1946, wildlife biologist Chuck Waldron established study plots on the 

three sites. His purpose was to analyze the vegetation of the plant communities 

there and to determine effects from big game (deer and elk) and livestock grazing 

and browsing. In 1962, range conservationist Emory Clapp and Waldron resampled 

the vegetation on Waldron’s plots and took photos at the 11 camera points he had 

established earlier. They attempted to compare Waldron’s earlier data with their 

1962 data. Waldron had employed the square-foot density method (Stoddart and 

Smith 1955) and they replicated the technique.

The 1946–1962 comparison—

Over 16 years (1946–1962), total forage increased on all three sites (table 3). The 

two exclosures exhibited the greatest increase (7 to 71 percent in the game exclosure; 7 to 63 percent in the livestock exclosure). Even in the open area, now with 

decreased ungulate pressure, forage species increased from 5 to 54 percent. The 

main contributors were the two principal bunchgrasses (bluebunch wheatgrass 

and Idaho fescue). Of the two bunchgrasses, Idaho fescue increased along with a 

consistent decline of bluebunch wheatgrass. The probable reason for the increase 

in fescue was the increased moisture retention caused by increased litter on the 

ground surface and increased foliar canopy shading helping to moderate the 

desiccating temperatures of the summer months. 
18

GENERAL TECHNICAL REPORT PNW-GTR-724

The other story over the period between samples was with bitterbrush. The 

shrub was stable over the period in the game exclosure where no browsing could 

occur. However, within the livestock exclosure and on the open control site, the 

shrubs were found to be severely hedged, decadent, and in jeopardy of loss to the 

communities. Within the game exclosure, the plants had full crowns developing 

from the previous hedged state, and juvenile shrubs were present providing a 

greater vitality to the community.

The 1981–2002 comparison—

In 1962, Parker 3-step condition and trend transects were installed within the 

game and livestock exclosures for initiating a new sampling technique that used 

a 3⁄4-inch loop to attain composition and frequency of the plants within the community (table 4). The open area plots were on a rocky site that was not comparable 

to the sites where the exclosures reside. The transects were resampled periodically. 

With the increase in elk populations of the 1980s, renewed sampling was conducted 

to observe the impact of dual usage by cattle and elk with the excluded communities as benchmarks. Key sample years were 1981 (prior to the peaking of elk use), 

1986 (at the peak of elk use), and 2002 (after the peak when elk numbers declined). 

In 1998, a fire burned through the exclosures. 

From 1981 to 1986, there was a slight increase in bluebunch wheatgrass and 

Idaho fescue in the game exclosure with a slight decrease of those grasses in the 

livestock exclosure where deer and elk could graze. Bitterbrush increased by 5 

percent within the game exclosure over this period. After the fire, bitterbrush 

mortality was severe. Within the game exclosure, 86 percent of the bitterbrush 

died within the sampled community. Foliar canopy coverage by bitterbrush 

declined from 21 percent to only 5 percent. Slight postburn increases in cover 

were made by prairie junegrass and yarrow. 

Table 3—Skookum three-way exclosures (square foot density method)

Game exclosure Livestock exclosure Open

1946 1962 1946 1962 1946 1962

Percent cover

Bitterbrush 12 13 6 2 8 t

Idaho fescue 17 40 22 33 19 37

Bluebunch wheatgrass 43 27 45 35 57 46

Total forage species 7 71 7 63 5 54

t = trace
19

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

The 1989–2003 comparison—

Ocular macroplots (table 5) were established in the exclosures and open control area 

in 1989 and 1993 for acquiring data to assist in the plant community classification 

project for the Blue Mountains. Observations resulting from the data acquired on 

these plots reinforce the trends demonstrated in the earlier work here. In the game 

exclosure, there was the least bare ground (30 percent), and litter was highest (60 

percent). In the livestock exclosure, bare ground (40 percent) was higher than in the 

game exclosure. In the open sample area, bare ground was highest of all sites at 55 

to 60 percent. 

Table 4—Skookum exclosures (Parker 3/4-inch loop technique)

Game exclosure Livestock exclosure

1981 1986 2002 1981 1986 2002

Percent cover

Bitterbrush 16 21 5 2 2 1

Idaho fescue 42 34 35 25 15 21

Bluebunch wheatgrass 21 35 31 30 37 25

Sandberg’s bluegrass 16 7 10 28 17 34

Prairie junegrass 1 1 4 0 0 1

Yarrow 2 1 7 0 0 1

Bare ground 27 22 23 63 35 39

Rock 6 8 3 1 1 2

Gravel 0 0 2 0 0 2

Moss 3 6 8 2 6 4

Lichen 0 0 1 0 0 2

Litter 41 51 62 17 49 52

Table 5—Skookum three-way exclosures (ocular macroplot)

Game exclosure Livestock exclosure Open

1989 2001 1993 2003 1993 2003

Percent cover

Bitterbrush 20 3 10 10 3 1

Idaho fescue 20 25 15 20 t 3

Bluebunch wheatgrass 25 20 30 15 10 20

Bare ground 30 30 40 40 60 55

Rock 3 3 5 3 30 10

Gravel t 5 1 1 5 5

Moss 1 0 1 t 1 1

Lichen 3 0 1 t 0 0

Litter 55 60 40 40 3 25

t = trace
20

GENERAL TECHNICAL REPORT PNW-GTR-724

Bitterbrush had open crowns with 3 to 4 foot branches inside the game exclosure. Inside the livestock exclosure, deer and elk had severely impacted the crowns 

of bitterbrush and the recruitment of juvenile shrubs. The burn of 1998 reduced 

the populations in the game exclosure to less than 5 percent but had less effect on 

the shrubs inside the livestock exclosure where fire had apparently traveled faster 

along the ground surface leaving the postburn community intact. The bunchgrasses 

remained stable inside the exclosures over the 1989–2003 period with the burn 

apparently not detrimentally affecting them.

The sampling in 2001 and 2003 encountered an invasive plant new to the plant 

community as well as northeastern Oregon. Ventenata, a European annual grass, 

apparently was introduced by animals and established in the grassland communities. It was not present in the sampled data previously. It is a disturbance opportunist and occurred with greatest cover in the open area (10 percent), less in the 

livestock exclosure (5 percent), and none within the game exclosure. 

Stumbough Exclosure (Established 1983)

In 1983, the Walla Walla Ranger District constructed a game exclosure near the end 

of Stumbough Ridge to assess the effect of elk and trespass horses on the bunchgrass vegetation of the gentle ridgetop. At the time of establishment, line transects 

were installed within the exclosure and in a similar vegetation outside the exclosure. The vegetation was initially sampled for percentage composition by using the 

Parker 3⁄4-inch loop technique. That technique was followed through the subsequent 

sampling periods. Although highly impacted, the vegetation fit the Idaho fescuebluebunch wheatgrass plant association (Festuca idahoensis-Agropyron spicatum) 

(Johnson and Clausnitzer 1992). Kentucky bluegrass thoroughly dominated at 66 

percent cover inside the exclosure and 61 percent cover outside (table 6). However, 

the two bunchgrasses, Idaho fescue and bluebunch wheatgrass, accounted for a 

cover of only 1 percent each inside the exclosure and a combined 15 percent outside 

the exclosure in 1983, a result of heavy use by ungulates prior to exclosure establishment. An invasive grass, Canada bluegrass (Poa compressa), was present at 3 

percent cover inside the exclosure and 11 percent cover outside. Yarrow and sheep 

sorrel (Rumex acetosella) were the dominant forbs with a cover of 8 percent each 

both inside and outside.

In 1989, 6 years later, Kentucky bluegrass cover had declined inside the exclosure by 7 percent with a minor increase of 1 percent (4 to 5) by bluebunch wheatgrass. It was even more dramatic outside. Kentucky bluegrass declined 44 percent 

to a cover of 17 percent with a slight increase by the bunchgrasses to a combined 

17 percent cover. The Canada bluegrass made only a slight increase inside the 

The sampling in 2001 

and 2003 encountered 

an invasive plant new 

to the plant community 

as well as northeastern 

Oregon. 
21

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

exclosure while it dramatically increased by 22 percent outside the exclosure. In 

1983, forbs were subordinate to the grasses. Outside the exclosure in 1989 there 

was a 12-percent increase in forb composition. These changes outside the exclosure 

were probably due to continued heavy use by ungulates coupled with the drought 

period in the mid 1980s. 

Nine years later in 1998, the vegetation was again sampled. The decline of 

Kentucky bluegrass continued. It now covered only 33 percent of the exclosure, 

half its area of extent within the exclosure 15 years previously in 1983. Outside the 

exclosure, Kentucky bluegrass also declined to just 12 percent cover from its 61 

percent cover of 1983. Canada bluegrass also was in decline and was now almost 

absent within the exclosure. Inside the exclosure, the two bunchgrasses continued to 

increase, doubling cover from 1989 to 12 percent. Invading both inside and outside 

the exclosure was a new plant for this site—goatweed (Hypericum perforatum). It 

covered large areas; 19 percent within the exclosure and 24 percent outside. Yarrow 

had also doubled from the 1983 population of 8 percent to a cover of 15 percent 

inside the exclosure. 

The last reading of the transects was in 2003—twenty years after the installation of the exclosure and the initiation of sampling vegetation. Kentucky bluegrass 

continued its decline inside the exclosure with cover now down to 26 percent from 

an initial 66 percent. It was even more dramatic outside where the bluegrass was 

all but eliminated, now just 2 percent cover. Idaho fescue continued to increase its 

occupancy most dramatically outside the exclosure where it now covered 30 percent 

of the ground and dominated over bluebunch wheatgrass. Idaho fescue increased 

as well within the exclosure but was still dominated by Kentucky bluegrass and 

bluebunch wheatgrass. The two bunchgrasses now were covering almost 50 percent 

Table 6—Stumbough exclosure

Game exclosure Open area

1983 1989 1998 2003 20-year trend 1983 1989 1998 2003 20-year trend

Percent cover

Kentucky bluegrass 66 59 33 26 ↓ 61 17 12 2 ↓

Idaho fescue 1 1 5 6 ↑ 3 7 23 30 ↑

Bluebunch wheatgrass 1 5 7 11 ↑ 12 10 13 19 ↑

Canada bluegrass 3 5 1 0 ↓ 11 33 12 10 →

Goatweed 0 1 19 13 ↑ 0 0 24 19 ↑

Yarrow 8 1 15 20 ↑ 4 3 3 8 →

Sheep sorrel 8 3 0 2 ↓ 7 7 0 0 ↓

Bare ground 4 10 1 5 → 9 21 9 26 ↑

Moss/lichen 2 1 1 1 → 2 7 3 3 →

Litter 73 70 75 78 → 63 50 55 49 ↓
22

GENERAL TECHNICAL REPORT PNW-GTR-724

of the open site while the increases in bunchgrasses were much less within the 

exclosure (now covering just 17 percent). What appeared to be impeding the rate of 

bunchgrass increase in the protected exclosure was the deep thatch of litter occupying the interstitial areas between perennial plants. There was a surface cover of litter of 78 percent within the exclosure! In contrast, there was only 49 percent cover 

by litter outside where ungulates used the plants. The percentage of bare ground 

was about 1 to 10 percent within the exclosure over the 20 years. In summation 

for the sites as a whole at this time, Kentucky bluegrass had continued to decline, 

bluebunch wheatgrass and Idaho fescue had continued to increase, and goatweed 

increased. 

Burrowing rodents (field mice [Peromyscus spp.], voles [Microtus spp.], and 

pocket gophers [Thomomys talpoides]) provided the principal disturbance within 

the exclosure over the years since 1983. They had been protected from their predators by the fencing. A higher “weediness” was exhibited within the exclosure as a 

result of the rodent population growth afforded by the cover of a deep litter layer 

on the surface of the ground. Outside the exclosure, ungulates (predominantly elk) 

had provided the principal disturbance. Their trampling displaced plants and also 

compacted the soil to a higher degree than the soils within the exclosure. 

Malheur National Forest Exclosures

The Malheur National Forest contains the greatest number of existing exclosures in 

northeast Oregon national forests with 17. The majority (9) were established in the 

mid 1950s to early 1960s to study the effects of livestock exclusion on the vitality of 

bitterbrush in key winter ranges. In the 1940s, the mule deer (Odocoileus hemionus) 

population exploded and outgrew the food supply on the winter range. Many deer 

starved. Contributing to the lack of food supply for deer was an explosive population increase by mice in the late 1930s and early 1940s (USDA FS 1961). 

In northeast Oregon, the oldest extant exclosures are found on the Malheur 

National Forest. The Wickiup one-way exclosure was installed in 1933 on a sedge 

meadow. The Canyon Creek three-way exclosure, constructed in 1936, represents 

the oldest protected site in the uplands. Both the Wickiup and Canyon Creek sites 

are located on the Blue Mountain Ranger District. Of the 18 exclosures on the 

Malheur National Forest, the majority were established as browse study plots by 

Forest wildlife staff Rodney J. Miller in the early 1960s. These one-way exclosures 

averaged 1⁄4 acre and principally enclosed bitterbrush communities. The majority of 

these exclosures are on the Emigrant Creek Ranger District. The remaining three 

are on the Blue Mountain Ranger District.

What appeared to be 

impeding the rate of 

bunchgrass increase in 

the protected exclosure 

was the deep thatch 

of litter occupying 

the interstitial areas 

between perennial 

plants. 
23

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Five three-way exclosures were established on sites where bitterbrush was 

a component. These usually enclosed areas of approximately 1 acre each. The 

remaining exclosures were single, smaller livestock-proof exclosures enclosing 

about a quarter-acre (from 0.2 to 0.4 acre). 

With one exception (Rainbow three-way), all of the exclosures installed 

included photopoint stakes/posts and transects for measuring the pellets of wild 

ungulates but did not include vegetation sampling transects. The author installed 

vegetation sample plots in each of the exclosures in 1994 and returned in 2004 to 

resample. Thus, the data spans only the last decade, but longer term changes can be 

inferred by comparing the different exclosures with the open plot. Photopoints were 

re-established in 1994 and retaken in 2004. 

The following five Malheur National Forest exclosures have been selected 

to demonstrate their value to scientists and specialists. Their integrity has been 

continuous (ungulates have been wholly or partially excluded per the intentions of 

those who constructed them). Exclosures that had been breached by ungulates they 

were constructed to exclude are not included in this selection.

Canyon Creek Three-Way Exclosures (Established 1936)

This exclosure on Bear Valley Ranger District (table 7) is one of the best exclosures 

in the study area from the standpoint of construction and long-term maintenance. 

Its fencing has not been breached, and repairs have been timely. The plant 

community is in the ponderosa pine/antelope bitterbrush/Idaho fescue-bluebunch 

wheatgrass plant association (Pinus ponderosa/Purshia tridentata/Festuca 

idahoensis-Agropyron spicatum) (Johnson and Clausnitzer 1992).

Table 7—Canyon Creek three-way exclosures

Game exclosure Livestock exclosure Open

1994 2004 1994 2004 1994 2004

Percent cover

Bitterbrush 20 24 t t 1 t

Bluebunch wheatgrass 5 3 10 3 5 5

Idaho fescue 10 20 10 15 30 25

Sandberg’s bluegrass 1 t 5 3 3 1

Prairie junegrass 1 t 1 1 1 t

Bare ground 5 5 15 3 10 1

Rock 10 10 20 15 10 15

Gravel 30 30 10 15 5 5

Moss 10 10 3 1 5 3

Lichen 5 5 10 3 1 1

Litter 15 35 35 60 40 70

t = trace
24

GENERAL TECHNICAL REPORT PNW-GTR-724

Game exclosure—

Bitterbrush and Idaho fescue both exhibited increases in cover. The open crowns 

to 4-foot stature of the enclosed bitterbrush plants is a sight not normally seen 

elsewhere in northeastern Oregon forests and rangelands; in marked contrast, the 

bitterbrush had severely hedged crowns in the surrounding community outside 

the game exclosure. Idaho fescue was dominant over bluebunch wheatgrass and 

doubled in cover over the decade.

Livestock exclosure—

A livestock-proof fence permits deer and elk to enter the stand adjacent to the game 

exclosure. Bitterbrush was severely hedged inside with no juvenile plants. Interestingly Idaho fescue also increased, as in the game exclosure, increasing in cover as 

bluebunch wheatgrass declined. Over the 10-year period since the previous sampling, bare ground has sharply declined with a large increase in ground surface now 

covered by litter (60 percent). This relationship between the bunchgrasses, litter 

accumulation, and decline in bare ground indicated a progressive successional trend 

with decreased use of the herbage by livestock. 

Open plot—

There was little change over the 10-year period where all ungulates could graze 

and browse. The bitterbrush was present now as only a trace with plants severely 

hedged. The bunchgrasses remained at or near their coverage levels from 10 years 

previous. Litter, which had increased in the exclosures, also had significantly 

increased here as well. 

The increase in litter with decline in bare ground appeared to be a reflection 

of less ungulate movement and less utilization in the livestock exclosure and in the 

open plot. In the game exclosure, bare ground was static at a low 5 percent. 

Antelope Spring Game Exclosure (Established 1955)

Unlike the adjacent livestock exclosure and open plot that have invasive exotic 

grasses, the game exclosure at Antelope Spring (also on Blue Mountain Ranger 

District) provides one of the best intact communities of protected bitterbrush in 

the exclosure system of northeast Oregon. It lost its integrity when wild horses and 

mule deer were able to enter the downed fencing of the exclosure in 1989–1990 

before repairs were made to re-establish the exclusion. It is now solidly reconstructed. The western juniper/bitterbrush/Idaho fescue-bluebunch wheatgrass plant 

community dominates the site (Juniperus occidentalis/Purshia tridentata/Festuca 

idahoensis-Agropyron spicatum) Johnson and Clausnitzer 1992.

The bitterbrush 

had severely 

hedged crowns in 

the surrounding 

community outside 

the game exclosure.
25

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Bitterbrush is uniformly 3 to 5 feet tall within the exclosure, and younger 

age classes are represented. Branches with annual growth may extend to 6 feet in 

height! This is a demonstration of the growth bitterbrush can achieve on the mountainous ridgetops at the upper limits (5,000 feet) of its elevational range in the Blue 

Mountains. Outside the exclosure, ungulates have hedged the shrubs severely, with 

most shrubs only 12 to 24 inches tall. Over the decade, bitterbrush increased its 

cover within the exclosure from 15 to 25 percent.

Western juniper has increased on the sample area inside the exclosure. In 1994, 

it was present at only 1 percent cover. Now young trees account for 6 percent cover. 

As with many of the rangelands in the southern Blue Mountains, western juniper is 

invading because of fire suppression. Certainly the lack of all disturbances within 

the exclosure over the past decade of monitoring has promoted its increase. There 

has been a stable cover of the herbaceous vegetation within the exclosure over the 

10-year sample period.

Venator Creek Exclosure (Established 1963)

This 1⁄4-acre livestock-proof exclosure on the Emigrant Creek Ranger District 

provides a good benchmark for a bitterbrush community containing the two 

principal bunchgrasses, Idaho fescue and bluebunch wheatgrass (Purshia 

tridentata/Festuca idahoensis-Agropyron spicatum) (Johnson and Clausnitzer 

1992). Unlike the bitterbrush at Antelope Springs, where all-ungulate exclusion has 

enabled the bitterbrush to establish multiple age classes and attain full crowns, the 

bitterbrush in this livestock-proof exclosure is susceptible to mule deer browsing. 

Deer use is high: over 90 percent of the shrubs are decadent and few have branches 

growing free of hedging. The decrease in cover by bluebunch wheatgrass from 30 

to 10 percent over the 1994–2004 sampling period may be attributed to grazing 

by deer and elk. It may also be attributed to drought, as mosses once as high as 20 

percent cover on the ground surface are presently now at only a trace. The loss of 

the mosses and bluebunch wheatgrass led to the doubling of the bare ground from 

25 percent in 1994 to 50 percent in 2004. During this sample period, Idaho fescue 

cover did not change.

Larsen Spring Exclosure (Established 1963)

Three exclosures in the Blue Mountains (Emigrant Creek Ranger District) include 

curlleaf mountain-mahogany. Larsen Spring exclosure is the best benchmark of 

a mountain-mahogany community: all age classes are well represented, assuring 

a future community of the shrub barring disturbance that jeopardizes the health 
26

GENERAL TECHNICAL REPORT PNW-GTR-724

and vitality of the plants. This exclosure is dominated by the curlleaf mountainmahogany (35 percent cover) compared to the 15 percent cover of ponderosa pine 

(Pinus ponderosa). The plant association here is ponderosa pine/curlleaf mountainmahogany/Idaho fescue-bluebunch wheatgrass (Pinus ponderosa/Cercocarpus 

ledifolius/Festuca idahoensis-Agropyron spicatum) (Johnson and Clausnitzer 

1992). Other prominent shrubs are mountain big sagebrush (Artemisia tridentata

var. vaseyana), wax currant (Ribes cereum), and bitterbrush. This livestockproof 1⁄4-acre exclosure enables wild ungulates to enter. The bitterbrush were 

decadent, hedged, and had increased only to 3 percent cover from the 1994 

sample. Mountain-mahogany increased by 5 percent during the same period. 

Dramatically increasing species were Idaho fescue (1 to 25 percent) and gray 

hawksbeard (Crepis intermedia), from 5 to 35 percent.

Skookum Spring Exclosure (Established 1963)

The 1⁄4-acre livestock exclosure near Skookum Spring on Capps Mountain (Emigrant Creek Ranger District) provides the best benchmark for the mountain big 

sagebrush/Idaho fescue-bluebunch wheatgrass plant association in the Blue Mountains (Johnson and Clausnitzer 1992). It was breached in 1994 at the time of the first 

sample but was quickly restored that season and has maintained its integrity since. 

Sagebrush dominates at 35 percent cover. Idaho fescue has been stable at 25 percent 

cover and is the dominant herbaceous plant. Bluebunch wheatgrass declined from 

10 to 3 percent cover. Concurrently, spurred lupine (Lupinus laxiflorus) increased 

from 3 to 20 percent over the same period.

Discussion of Results

The key finding of the three-way exclosure sampling over time is that the plant 

communities within the livestock exclosure are generally the densest and most 

vigorous. Many studies have demonstrated that long-term herbivory can increase 

the dominance of highly palatable plants (Augustine and McNaughton 1998, Parker 

et al. 2006). Bunchgrasses are stimulated by wild ungulate use: seedlings emerge 

from the bare ground left by light trampling and are afforded early moisture retention by moderate or light litter levels. 

In contrast, the bunchgrass plant communities within the game exclosure tend 

to become decadent over time as thatch builds from lack of ungulate utilization. 

Rodent populations tend to have the greatest increase in game exclosures capitalizing on the increased cover and lack of predation. The lack of utilization of bunchgrass vegetation allows a deep thatch of herbaceous litter to build over time and 

provide protected runways and burrow cover. Mammalian predators are thwarted 

The key finding of the 

three-way exclosure 

sampling over time 

is that the plant 

communities within the 

livestock exclosure are 

generally the densest 

and most vigorous. 
27

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

by the coyote-proof fencing usually employed at the lower levels of game exclosures, and raptors are less successful in seeing the prey from flight. The vegetation 

becomes progressively weedier with invasive plants occupying areas of disturbance 

from the rodents. The livestock exclosures have repeatedly demonstrated that 

bunchgrass vegetation is healthier when stimulated by natural disturbances of 

fire and native ungulates, and that total exclusion afforded by game exclosures is 

detrimental to perennial bunchgrasses.

In the plant communities of the Idaho fescue-prairie junegrass plant association, with exclusion of ungulates, Kentucky bluegrass (Poa pratensis) has declined 

and Idaho fescue (Festuca idahoensis) increased over time. The only exceptions 

occur when Kentucky bluegrass is not a component and at Lord Flat where the 

native vegetation was once plowed under and is still in the early stages of development. 

Bluebunch wheatgrass (Agropyron spicatum) has either declined or remained 

static with dominance by Idaho fescue in the ungulate exclosures. No upward trend 

in bluebunch wheatgrass abundance has occurred at the five Wallowa Mountain 

sites with exclusion. Prairie junegrass (Koeleria cristata) has remained static (no 

significant change) at these sites with or without exclusion. 

The most overgrazed site (Grizzly Ridge) exhibits a consistent decline by all 

deep-rooted bunchgrasses inside and outside the exclosure. It exemplifies how, on 

a droughty site, exclusion of grazers may not result in recovery even after decades 

have passed. Here Kentucky bluegrass was not a component at the time of exclosure 

installation in 1971. Onespike oatgrass (Danthonia unispicata) was a component 

of the communities within the Grizzly Ridge exclosures in 1971, but did not occur 

in the sampled open area. Interestingly, with a combination of overgrazing and 

drought, the deep-rooted bunchgrasses (Idaho fescue and bluebunch wheatgrass) 

have been eliminated since 1977 in the open area with dominance now achieved by 

onespike oatgrass. 

The invasive exotic, Ventenata dubia, has spread across the mountainous 

rangelands and canyon lands of the inland Pacific Northwest including where 

exclosures were present prior to the invasion. This annual grass requires active soil 

disturbance for establishment. Populations of ventenata were highest in open areas 

where ungulates made the greatest impact from trampling. Ventenata was less pronounced in the livestock exclosures and absent in the game exclosures. At the open 

sample site at Pleasant Valley, when wildfires burned and provided a barren ground 

surface, ventenata dramatically dominated the year after the fire. However, within 5 

years it was replaced by other plants and was no longer part of the plant community. 
28

GENERAL TECHNICAL REPORT PNW-GTR-724

In general, annual forbs and grasses dominated in the year after fires in bunchgrass communities. Replacement by perennial forbs and grasses was well underway 

5 years after the fire. Native perennial grasses performed predictably in bunchgrass 

communities burned by wildfires. Both Sandberg’s bluegrass and prairie junegrass 

increased following moderate burns but declined to preburn levels within the first 5 

years. Idaho fescue and bluebunch wheatgrass declined in cover from moderate and 

severe burns in the first 5 years but rebounded thereafter (especially when protected 

from all ungulates within the game exclosures). In the communities of the central 

and southern Blue Mountains, western juniper is invading the deeper soil in bitterbrush sites sampled within exclosures. 

The impacts on shrubs, resulting from browsing ungulates, was demonstrated 

by some exclosures in shrubland communities. At Pleasant Valley in the Snake 

River Canyon, the game exclosure dramatically encloses a dense rhizomatous 

shrubland. Outside in the open area, Kentucky bluegrass was the dominant 

vegetation with minor shrub composition owing to heavy use by livestock and 

wild ungulates. With the cessation of use by livestock, the lesser use by elk and 

deer is allowing the emergence of the shrubs. Perhaps no single exclosure within 

the study area so dramatically displays the zoomorphic influence on vegetation.

The bitterbrush community exclosures located in the central and southern 

Blue Mountains have demonstrated the impact that browsing animals have made 

on this shrub. Within the game exclosures, bitterbrush has emerged with long, 

free-branching crowns from a hedged state. In stark contrast, the shrubs located 

in the open areas have remained severely hedged or have died.

Metric and English Equivalents

When you know: Multiply by: To find:

Inches (in) 2.54 Centimeters (cm)

Inches (in) .254 Decimeters (dm)

Feet (ft) .3048 Meters (m)

Acres (ac) .405 Hectares (ha)

Within the game 

exclosures, bitterbrush 

has emerged with long, 

free-branching crowns 

from a hedged state. 

In stark contrast, the 

shrubs located in 

the open areas have 

remained severely 

hedged or have died.
29

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Literature Cited

Allen, B.H. 1986. Remember rangeland reference areas? Rangelands. 8(4): 180-182.

Anderson, K.L.; Smith, E.F.; Ownsby, C.E. 1970. Burning bluestem range. 

Journal of Range Management. 23: 81–92.

Augustine, D.J.; McNaughton, S.J. 1998. Ungulate effects on the functional 

species composition of plant communities: herbivore selectivity and plant 

tolerance. Journal of Wildlife Management. 62(4): 1165–1183.

Daubenmire, R. 1959. A canopy-coverage method of vegetation analysis. 

Northwest Science. 33(1): 43–64.

Evanko, A.B.; Peterson, R.A. 1955. Comparisons of protected and grazed 

mountain rangelands in southwestern Montana. Ecology. 36(1): 71–82.

Garrison, G.A. 1953. Effects of clipping on some range shrubs. Journal of Range 

Management. 6: 309–317.

Hitchcock, C.L.; Cronquist, A. 1973. Flora of the Pacific Northwest. Seattle, WA: 

University of Washington Press. 730 p. 

Johnson, C.G., Jr.; Clausnitzer, R.R. 1992. Plant associations of the Blue and 

Ochoco Mountains. R6-ERW-TP-036-92. Portland, OR: U.S. Department of 

Agriculture, Forest Service, Pacific Northwest Region. 208 p. 

Johnson, C.G., Jr.; Simon, S.A. 1987. Plant associations of the Wallowa-Snake 

Province. R6-ECOL-TP-225A-86. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Region. 400 p.

Laycock, W.A. 1975. Rangeland reference areas. Range Science Series No. 3. 

Denver, CO: Society for Range Management. 66 p.

Parker, J.D.; Burkepile, D.E.; Hay, M.E. 2006. Opposing effects of native and 

exotic herbivores on plant invasions. Science. 311: 1459–1461. 

Parker, K.E. 1951. A method for measuring trend in range conditions on national 

forest ranges. Washington, DC: U.S. Department of Agriculture, Forest Service. 

26 p.

Pickford, G.D. 1932. The influence of continued heavy grazing and promiscuous 

burning on spring-fall ranges of Utah. Ecology. 13: 159–171.

Stoddart, L.A.; Smith, A.D. 1955. Range management. New York: 

McGraw-Hill. 433 p.
30

GENERAL TECHNICAL REPORT PNW-GTR-724

Tueller, P.T.; Tower, J.D. 1979. Vegetation stagnation in three-phase big game 

exclosures. Journal of Range Management. 32(4): 256–263.

U.S. Department of Agriculture, Forest Service [USDA FS]. 1961. Wildlife 

habitat management plan. John Day, OR: Pacific Northwest Region, Malheur 

National Forest. 21 p.

U.S. Department of Agriculture, Forest Service [USDA FS]. 1965a (June 14).

Memorandum. Fenced observation plots-exclosures. Portland, OR: Pacific 

Northwest Region. 33 p. On file with: Wallowa-Whitman National Forest 

Supervisor’s Office, P.O Box 907, Baker City, OR 97814.

U.S. Department of Agriculture, Forest Service [USDA FS]. 1965b. Guide for 

reading game study plots. Forest Service Manual. Wallowa-Whitman National 

Forest Supplement. Baker City, OR: Wallowa-Whitman National Forest. 21 p.

U.S. Department of Agriculture, Natural Resources Conservation Service 

[USDA NRCS]. 2004. The PLANTS database, Version 3.5 [database]. Baton 

Rouge, LA: National Plant Data Center. http://plants.usda.gov. (January 2005). 
31

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Appendix 1: Plants Listed by Scientific Name

Scientific namea PLANTS codeb Common namea

Abies grandis (Dougl. ex D. Don) Lindl. ABGR grand fir

Achillea millefolium L. ssp. lanulosa (Nutt.) Piper ACMIL common yarrow

Agropyron spicatum (Pursh) Scribn. & J.G. Sm. AGSP bluebunch wheatgrass

Anthriscus scandicina (Weber ex Wiggers) Mansf. ANSC8 chervil

Arenaria serpyllifolia L. ARSE2 thymeleaf sandwort

Artemisia tridentata Nutt. var. vaseyana (Rydb.) Beetle ARTRV mountain big sagebrush

Balsamorhiza sagittata (Pursh) Nutt. BASA3 arrowleaf balsamroot

Bromus carinatus Hook. & Arn. BRCA5 mountain brome

Calamagrostis rubescens Buckl. CARU pinegrass

Carex sp. L. CAREX sedge species

Cercocarpus ledifolius Nutt. CELE3 curlleaf mountain-mahogany

Chrysothamnus nauseosus (Pallas ex Pursh) Britt. CHNA2 gray rabbitbrush

Clintonia uniflora (Menzies ex J.A. & J.H. Schultes) Kunth CLUN2 beadlily

Crepis intermedia Gray CRIN4 gray hawksbeard

Danthonia unispicata (Thurb.) Munro ex Macoun DAUN onespike oatgrass

Eriogonum heracleoides Nutt. ERHE2 creamy buckwheat

Festuca idahoensis Elmer FEID Idaho fescue

Galium aparine L. GAAP2 cleavers; bedstraw

Galium trifidum Michx. GATR3 small bedstraw

Geranium viscosissimum Fisch. & C.A. Mey. ex C.A. Mey. GEVI2 sticky geranium

Geum triflorum Pursh GETR red avens

Hypericum perforatum L. HYPE goatweed

Juniperus occidentalis Hook. JUOC western juniper

Koeleria cristata auct. p.p. non Pers. KOCR prairie junegrass

Lupinus laxiflorus Dougl. ex Lindl., non Amer. auct. LULA3 spurred lupine

Lupinus sericeus Pursh LUSE4 silky lupine

Pinus ponderosa P.& C. Lawson PIPO ponderosa pine

Poa compressa L. POCO Canada bluegrass

Poa pratensis L. POPR Kentucky bluegrass

Poa secunda J. Presl POSE Sandberg’s bluegrass

Potentilla gracilis Dougl. ex Hook. POGR9 slender cinquefoil

Pseudotsuga menziesii (Mirbel) Franco PSME Douglas-fir

Purshia tridentata (Pursh) DC. PUTR2 antelope bitterbrush

Ribes cereum Dougl. RICE wax currant

Rosa sp. L. ROSA rose species

Rumex acetosella L. RUAC3 sheep sorrel

Stipa occidentalis Thurb. ex S. Wats. STOC2 western needlegrass

Symphoricarpos albus (L.) Blake SYAL common snowberry

Symphoricarpos oreophilus Gray SYOR2 mountain snowberry

Taxus brevifolia Nutt. TABR2 Pacific yew

Tragopogon dubius Scop. TRDU yellow salsify

Ventenata dubia (Leers) Coss. & Durieu VEDU ventenata

a

Hitchcock and Cronquist 1973.

b

USDA NRCS 2004.
32

GENERAL TECHNICAL REPORT PNW-GTR-724

Appendix 2: Plants Listed by Common Name

Common namea Scientific namea PLANTS codeb

antelope bitterbrush Purshia tridentata PUTR2

arrowleaf balsamroot Balsamorhiza sagittata BASA3

beadlily Clintonia uniflora CLUN2

bluebunch wheatgrass Agropyron spicatum AGSP

Canada bluegrass Poa compressa POCO

chervil Anthriscus scandicina ANSC8

cleavers; bedstraw Galium aparine GAAP2

common snowberry Symphoricarpos albus SYAL

common yarrow Achillea millefolium var. lanulosa ACMIL

creamy buckwheat Eriogonum heracleoides ERHE2

curlleaf mountain-mahogany Cercocarpus ledifolius CELE3

Douglas-fir Pseudotsuga menziesii PSME

goatweed Hypericum perforatum HYPE

grand fir Abies grandis ABGR

gray hawksbeard Crepis intermedia CRIN4

gray rabbitbrush Chrysothamnus nauseosus CHNA

Idaho fescue Festuca idahoensis FEID

Kentucky bluegrass Poa pratensis POPR

mountain big sagebrush Artemisia tridentata var. vaseyana ARTRV

mountain brome Bromus carlinatus BRCA5

mountain snowberry Symphoricarpos oreophilus SYOR2

onespike oatgrass Danthonia unispicata DAUN

Pacific yew Taxus brevifolia TABR2

pinegrass Calamagrostis rubescens CARU

ponderosa pine Pinus ponderosa PIPO

prairie junegrass Koeleria cristata KOCR

red avens Geum triflorum GETR

rose species Rosa sp. ROSA

Sandberg’s bluegrass Poa secunda POSE

sedge species Carex sp. CAREX

sheep sorrel Rumex acetosella RUAC3

silky lupine Lupinus sericeus LUSE4

slender cinquefoil Potentilla gracilis POGR9

small bedstraw Galium trifidum GATR3

spurred lupine Lupinus laxiflorus LULA3

sticky geranium Geranium viscosissimum GEVI2

thymeleaf sandwort Arenaria serpyllifolia ARSE2

ventenata Ventenata dubia VEDU

wax currant Ribes cereum RICE

western juniper Juniperus occidentalis JUOC

western needlegrass Stipa occidentalis STOC2

yellow salsify Tragopogon dubius TRDU

a

Hitchcock and Cronquist 1973.

b

USDA NRCS 2004.
33

Rangeland Exclosures of Northeastern Oregon: Stories They Tell (1936–2004)

Appendix 3: Area 3 Permanent Upland Exclosures

Malheur, Umatilla, and Wallowa-Whitman National Forests

Exclosure District Established Legal description Size Plant community

Acres

Malheur National Forest:

Canyon Creek 3-Way Blue Mountain 1936 T15S,R32E,SEC.17 G = 1.0; S = 1.1 PIPO/PUTR/FEID-AGSP

Antelope Spring Blue Mountain 1955 T15S,R28E,SEC.31 G = 1.4 JUOC/PUTR/FEID-AGSP

Wickiup Blue Mountain 1933 T16S,R29E,SEC. 3 CAREX Meadow

Birch Creek 3-Way Blue Mountain 1961 T12S,R29E,SEC.22 G = 1.1 CELE/PUTR/AGSP

Donaldson Ridge Blue Mountain 1963 T12S,R29E,SEC. 6 S only = 0.3 PIPO/PUTR/AGSP-POSE

Dry Creek 3-Way Blue Mountain 1939 T12S,R30E,SEC.30 G = 1.1 AGSP-POSE-ERHE2

Hamilton Ridge Blue Mountain 1963 T10S,R28E,SEC.25 S only = 0.3 PUTR/AGSP/POSE-DAUN

Raddue #4 Blue Mountain 1963 T12S,R30E,SEC.1 PUTR/AGSP

Raddue Ridge 3-Way Blue Mountain ? T11S,R30E,SEC.35 G = 1.1; S = 1.1 PIPO-JUOC/CELE-SYOR

Cougar Creek 3-Way Prairie City 1966 T18S,R35E,SEC.11 G = 1.1; S = 1.3 PUTR-ARTRV/FEID-AGSP

Gilbert Ridge Emigrant Creek 1963 T18S,R28E,SEC.12 S only = 0.2 PIPO/ARTRV/FEID-AGSP

Venator Creek Emigrant Creek 1963 T18S,R29E,SEC.20 S only = 0.2 PUTR/FEID-AGSP

Larsen Spring Emigrant Creek 1963 T21S,R31E,SEC. 3 S only = 0.2 PIPO/CELE/FEID-AGSP

Jake Green Spring Emigrant Creek 1963 T21S,R32.5E,SEC.14 S only = 0.2 ARTRV/FEID-AGSP

Whiting Spring Emigrant Creek 1963 T20S,R31E,SEC.30 S only = 0.4 ARTRV/FEID-KOCR

Skookum Spring Emigrant Creek 1963 T19S,R33E,SEC.12 S only = 0.3 ARTRV/FEID-AGSP

Duck Creek Emigrant Creek 1950 T18S,R33.5E,SEC.14 G only = 1.0 ARTRV/FEID-KOCR

Rainbow 3-Way Emigrant Creek 1957 T20S,R29E,SEC. 2 G = 1.0; S = 1.0 PUTR-ARTRV/FEID-AGSP

Umatilla National Forest:

Skookum 3-Way Heppner 1945 T6SW,R28E,SEC.30 JUOC/PUTR/FEID-AGSP

Long Hollow 3-Way North Fork John Day 1962 T6S,R32E,SEC.7 AGSP-POSA3

Pine Grove 3-Way North Fork John Day 1962 T6S,R32E,SEC.20 FEID-AGSP

Stumbough Walla Walla 1983 2N,R36E,SEC.9 FEID-AGSP

Pataha RNA Pomeroy Transects 1960 T9N,R42E,SEC.1 FEID-KOCR MOUND

Mottet Walla Walla 1965 T4N,R39E,SEC.20 ABGR/TABR/CLUN

Hoodoo Walla Walla 1965 T5N,R42E,SEC.8 ABGR/CLUN

Wallowa-Whitman National Forest:

Allen Springs 3-Way Wallowa Valley 1963 T5N,R45E,SEC.24 FEID-KOCR RIDGE

Coffee Pot 3-Way Hells Canyon 1969 T2N,R49E,SEC.23 FEID-KOCR RIDGE

Corral Gulch 3-Way Pine 1962 T8S,R45E,SEC.23 G = 1.1; S = 1.2 ARTRV-PUTR/FEID

Grizzly Ridge 3-Way Hells Canyon 1969 T2N,R48E,SEC.34 FEID-KOCR RIDGE

Goose Creek 3-Way Pine 1964 T8S,R43E,SEC. 3 ARTRV-PUTR/FEID

Lord Flat 3-Way Hells Canyon 1969 T2N,R50E,SEC. 7 G = 1.0; S = 3.5 FEID-KOCR RIDGE

Mormon Flat 3-Way Hells Canyon 1969 T2N,R50E,SEC.29 G = 1.2; S = 2.8 FEID-KOCR MOUND

Pleasant Valley 3-Way Hells Canyon 1969 T2N,R51E,SEC.19 G = 1.1; S = 1.7 SYAL-ROSA

Three Cent 3-Way Unity 1962 T10S,R36E,SEC.12 G = 0.9; S = 1.3 ECOTONAL (Shrub-grass)

Bald Mountain Baker 1940s T11S,R38E,SEC. 7 ABGR/CARU

Sumpter 3-Way Baker 1962 T10S,R37E,SEC.15 G = 1.1; S = 2.4 PIPO/PUTR/FEID

Little Sheep 3-Way Eagle Cap 1964 T2S,R41E,SEC.14 PSME/SYAL

G = Game (10-foot fence).

S = Livestock (4-foot fence).

Pacific Northwest Research Station

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