Variation in Shrub and Herb Cover 

and Production on Ungrazed Pine 

and Sagebrush Sites in Eastern 

Oregon: A 27-Year Photomonitoring 

Study

Frederick C. Hall

United States 

Department of 

Agriculture

Forest Service

Pacific Northwest 

Research Station

General Technical

Report

PNW-GTR-704

February 2007
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Author

Frederick C. Hall was senior ecologist (now retired), U.S. Department of Agriculture, Forest Service, Pacific Northwest Region, Natural Resources, P.O. Box 3623, 

Portland, OR 97208-3623. This paper was prepared in cooperation with the Pacific 

Northwest Region.

Cover photos

The photos on the cover depict the change in vegetation, from one year to the next, 

at the same sample point. The top photo was taken in 1994 and the bottom photo 

was taken one year later in 1995. Photos by Frederick C. Hall.
Abstract

Hall, Frederick C. 2007. Variation in shrub and herb cover and production on 

ungrazed pine and sagebrush sites in eastern Oregon: a 27-year photomonitoring study. Gen. Tech. Rep. PNW-GTR-704 Portland, OR: U.S. Department of 

Agriculture, Forest Service, Pacific Northwest Research Station. 44 p.

Study objectives were to evaluate yearly fluctuations in herbage canopy cover and 

production to aid in defining characteristics of range condition guides. Sites are 

located in the forested Blue Mountains of central Oregon. They were selected from 

those used to develop range condition guides where soil, topographic, and vegetation parameters were measured as a characterization of best range condition. Plant 

community dominants were ponderosa pine/pinegrass, ponderosa pine/bitterbrush/

Idaho fescue savanna, low sagebrush/bluebunch wheatgrass, and rigid sagebrush 

scabland. None of the sites were grazed during the previous 30 years or during the 

27-year study. Each location was permanently marked by fence posts, and a meter 

board was placed 10 m down an established transect line. Photographs (color slides) 

were taken down the transect with closeups left and right of the meter board. Sampling was limited to August 1–4 each year when canopy cover and herbage production were determined. Both total canopy cover and herbage production varied by 

about a 2.4-fold difference on each site over the 27 years. Apparently “good range 

condition” may be something of a “running target” and lacks a well-defined set of 

parameters. Canopy cover is a poor parameter for characterizing range condition. 

Three of the four plant communities were dominated by bunchgrasses. Abundance 

of seedheads is commonly used to indicate good range health. But on these sites, 

seedheads were not produced about half the time. Because these sites were in “good 

range condition,” lack of seedhead production may indicate maximum competition 

in the community. Maximum competition and maximum vigor do not seem to be 

synonymous. These bunchgrass communities varied in their greenness on the first 

of August each year from cured brown to rather vibrant green suggesting important 

annual differences in phenology. The pinegrass community, being dominated by 

rhizomatous species, showed surprising variance in seedhead production. Pinegrass 

did not flower, but Wheeler’s bluegrass, lupine, and Scouler’s woolyweed were quite 

variable, averaging inflorescences only 75 percent of the time.

Keywords: Range condition, flowering, canopy cover, herbage production, 

bunchgrass, yearly variability.
Contents

1 Introduction

1 Plant Communities

2 Methods

2 Photomonitoring

2 Canopy Cover

3 Herbage Production

	 3	 Image Identification

3 Photomonitoring

4 Viewing Images

5 Ponderosa Pine/Pinegrass Site: Herbage Dominance and Production

10 Comments

13 Ponderosa Pine/Bitterbrush/Idaho Fescue Site: Herbage Dominance 

 and Production

20 Comments

23 Low Sagebrush/Bluebunch Wheatgrass Site: Herbage Dominance 

 and Production

28 Comments

31 Rigid Sagebrush Scabland Site: Herbage Dominance and Production

36 Comments

39 Summary

39 Canopy Cover

39 Ratio of Cover to Productivity

39 Image Evaluation

41 Species List: Common Names

42 Species List: Codes

42 English Equivalents

43 Literature Cited
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon



Introduction

Use of range condition guides presupposes that vegetation characteristics of good 

condition are reasonably consistent from year to year. The validity of this concept 

warrants consideration because it forms the basis for determining fair and poor 

range condition as part of an appraisal of range health, which determines the need 

for livestock adjustment. Seventeen sites representative of common range plant 

communities in the Blue Mountains of eastern Oregon were monitored August 

1 to 4 from 1976 to 2006 for yearly changes in species dominance and herbage 

production at a consistent time of year. They were selected from those sites sampled 

to develop range condition guides by using the 3-Step Method (Parker and Harris 

1959).

Plant Communities

Four common plant communities were chosen for this report: ponderosa pine/pinegrass,

ponderosa pine/bitterbrush/Idaho fescue savanna, low sagebrush/bluebunch wheatgrass, 

and rigid sagebrush scabland.1 Data show that there is variability in species canopy cover 

and total herbage production between years. The data raise questions about the concept of 

a single set of criteria for “good” in range condition guides. The data also raise questions 

about what kind of sampling system is appropriate for characterizing these guides. 

Ponderosa pine/pinegrass, often with Douglas-fir and grand fir, is the most 

widespread forested plant community, that is also grazed, east of the Cascade crest 

in both Oregon and Washington. As tree cover increases, shrub and herb species 

density, composition, and production decreases (USDA FS 1967a). 

Ponderosa pine/bitterbrush/Idaho fescue is the second most common forested 

plant community that is grazed east of the Cascade crest. It represents the transition 

from grassland or sagebrush to forest as precipitation increases. And it, like ponderosa/pinegrass, suffers from a reduction of herbaceous species with an increase 

in tree cover. But it occupies a unique place in forested rangeland. Tree density 

for 1-in diameter growth per decade (Hall 2004) is so low that tree canopy, at this 

density, does not significantly affect herbaceous cover or production. However, tree 

cover in stagnated stands does reduce herbage production. Tree density also affects 

tree growth in both height and diameter. Grass canopy cover can reach 70 percent 

and herbage production 400 kg/ha.

Low sagebrush/bluebunch wheatgrass, the third most widespread plant community, occurs within the forest zone on soils too shallow for pine or fir. Juniper 

1 See “Species List” for Latin names of species in this publication.
General TEchnical REport PNW-GTR-704



can colonize these sites. Grass seedhead production on these areas is a trait evaluated by photo interpretation. The parameter evaluated is the number of bunchgrass 

plants that flowered by August 1. Canopy cover can reach 70 percent and herbage 

production 600 kg/ha.

Rigid sagebrush scabland was the fourth most widespread kind of plant community studied. It occurs within the forest zone on very shallow soils, 1.5 to 3.0 

dm deep, on poorly cracked bedrock. Soils are so shallow that they become waterlogged during winter. Soil protection is afforded by a gravel and stony cover with 

biological species such as moss and lichens intertwined. Herbaceous cover may 

reach 45 percent and production 250 kg/ha. 

Methods

August 1 to 4 was established as the time of year to sample. It was established as a 

reference point for plant phenological development including greenness, seedhead 

production, canopy cover, and herbage production. 

Photomonitoring

Photomonitoring (Hall 2002) was used to illustrate yearly changes based on recommendations by Reppert and Francis (1973) in their appraisal of the 3-Step Method. 

Their procedure was adapted as follows: (1) Each site was identified with steel fence 

posts or concrete reinforcing bars in rigid sagebrush sites. (2) The camera location 

was placed at the 0-ft end of the original range condition sampling transect. (3) A 

board 1 meter tall and marked in even decimeters was placed at the 10-m (33-ft) 

transect location and three images were recorded: a general view from the 0-ft end 

of the tape, and two at 2 m from the board, a view left of the meter board, and a 

view right of the board. These were used to appraise seedhead production, change 

in soil surface conditions, greenness of the vegetation, and as a check on estimates 

of canopy cover. Because of space limitations, only the right meter board image has 

been used. 

Canopy Cover

At each side of the meter board a 1-m square plot frame was placed to document 

canopy cover and estimate total herbage production. One decimeter marks were 

placed at each corner of the meter square to facilitate canopy estimates as a 1-dm 

square is 1 percent cover. Continuous vegetation (no open space) over at least 66 

percent of the 1-dm square constitutes 1 percent cover. 
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

Herbage Production

Herbage production was also estimated by using the 1-dm square. Near the sample 

site, a 1-m square area was selected on which to adjust ocular herbage production 

estimates. The area would be estimated and then clipped to measure grams of dry 

matter. To focus attention on plant biomass, a 1-dm square area around each plant 

was evaluated to determine how many 1-square dm areas were covered by a plant; 

then grams were estimated. This simply focused my attention on plant biomass. 

Herbage samples were air dried.

Other observations were noted at each site. Subsequent careful observation of 

recorded images revealed items missed in the field. I was surprised at how much 

could be “seen” by comparing images year by year. Rocks “moved,” trees came 

and went, bunchgrass plants shifted location, foliage color changed, foliage length 

varied, and seedheads were amazingly variable by number of plants, by number per 

plant, and by shift in plant location. 

Image Identification

The USDA Forest Service Pacific Northwest Region has developed a system for 

archiving images, mostly color slides. About 5,000 long-term study slides have 

been identified and categorized to be made available online. All images used here 

have been identified by a code consisting of an alphanumeric site identification. For 

example, the ponderosa pine/bitterbrush/Idaho fescue site code is 203EPF identifying ecology plot 203 and is read as “plot 203 ecology plot forage.” Tables in this 

publication use the archiving codes to facilitate access to the slides. 

Photomonitoring

All images used here are the same colors found on the slides. In no case was color altered. 

A few times brightness was altered to modify effects of shadows. Note that images from 

1957 to 1960 show effects of color fade. Kodak Ektachrome 2 was used in preference to 

Kodachrome because the latter gave too much red and an unrealistic color to vegetation. 

Ektachrome ISO was 100 in 1957 and 200 after 1966. 

Capturing the subtleties of greenness in August proved to be a challenge. The 

degree of greenness varied considerably. 

2 Use of firm or trade names in this publication is for reader information and does not imply 

endorsement by the U.S. Department of Agriculture of any product or service.
General TEchnical REport PNW-GTR-704

Camera technique was important in comparing images (Hall 2002). First, both 

camera location and photopoint at the meter board must be permanently marked 

with steel fence posts or stakes. The meter board for general pictures was used 

to orient the camera by focusing on the “1M.” Then it was used to photograph a 

specific tract of ground for repeat images. This requires another camera location in 

front of the board. For camera focal length of 50mm, the camera was held 2 m from 

the board. The camera was oriented to place the board at one side of the image so it 

reached from top to bottom. 

Digital cameras usually have zoom lenses so distance is very critical if any 

kind of change is to be documented. For general images, the zoom was adjusted to 

show the meter board at 25 percent of the image height. For the closeup images, the 

camera is oriented 2 m in front of the board and zoomed to just fill the one side of 

the image with the board. 

Viewing Images

Each of the following four sections is organized with an introductory page followed 

by four pages of images to the right of the meter board. When the pages are opened, 

one can view 12 years. Read from left to right across both pages.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

Ponderosa Pine/Pinegrass Site: 

Herbage Dominance and Production

This site is located at the south edge of Big Summit Prairie, Lookout Mountain District, Ochoco National Forest.

The area was historically a sheep allotment but was converted to a cattle allotment after the Second World War. 

It was selected because both woody and herbaceous vegetation seem near site potential for the area (USDA FS 

1967a). All sampling was done between August 1 and 4 starting in 1979 to the present. 

All images are shown as they appear on color slides of Kodak Ektachrome, ISO 200. In 1986, the roll of film 

was overexposed and the images are not presented here. 

The intent was to show yearly differences in both species dominance and seasonal color. 

1979: The ponderosa pine/pinegrass site during a drought. The 

log to the right of the meter board appears in all subsequent images of herbage species. Note the slight differences in dominance 

of pinegrass. This is due to variation in Mazama ash depth. Less 

ash means less vigor of pinegrass and more vigor of elk sedge. 

The image for 1986 is not included. 

Soil profile shows ash depth of 0.5 to 0.6 m over a buried soil. 

Basalt bedrock produced a moderately stony clay-loam soil. 

1979: View right of the meter board: pinegrass 40 percent cover, 

elk sedge 10 percent, and dried lupine 10 percent cover; 300 kg/ha 

herbage production. A pine seedling is next to the meter board 

between 6 and 8 dm. It was missing by 1982.
General TEchnical REport PNW-GTR-704

1980: Percent cover: pinegrass 55, elk sedge 20, lupine 15, 

Wheeler’s bluegrass 5; herbage production 650 kg/ha.

1981: Percent cover: pinegrass 50, elk sedge 25, Wheeler’s bluegrass 25 (seed heads), no lupine; herbage production 550 kg/ha. 

1984: Percent cover: pinegrass 55, lupine 30 (white seed heads), 

elk sedge 20; herbage production 600 kg/ha.

1985: Percent cover: pinegrass 35, lupine (dry) 30, elk sedge 15, 

Scouler’s woolyweed 5; herbage production 425 kg/ha.

1989: Percent cover: pinegrass 45, lupine 25 (white seed heads), 

elk sedge 20; herbage production 500 kg/ha.

1990: Percent cover: pinegrass 60, Wheeler’s bluegrass 15 (seed 

heads), Scouler’s woolyweed 5; herbage production 600 kg/ha. 
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

1982: Percent cover: pinegrass 40, lupine 20, elk sedge 15, Wheeler’s bluegrass 5; herbage production 450 kg/ha. Pine now dead.1983: Percent cover: pinegrass 50, elk sedge (dark green) 25, herbage production 400 kg/ha. Pine seedlings top right near log.

1987: Percent cover: pinegrass 40, lupine 25, elk sedge 20; herbage production 500 kg/ha. 1988: Percent cover: pinegrass 55, lupine 35 (brown), Scouler’s 

woolyweed 10; herbage production 600 kg/ha. 

1991: Percent cover: pinegrass 55, lupine 20, Wheeler’s bluegrass 

10, Scouler’s woolyweed 15; herbage production 600 kg/ha.

1992: Percent cover: pinegrass 40, lupine 10, Wheeler’s bluegrass 

20; herbage production 500 kg/ha. Pine seedlings top right. 
General TEchnical REport PNW-GTR-704

1993: Percent cover: pinegrass 55, lupine 15, Wheeler’s bluegrass 

10, elk sedge 10; herbage production 675 kg/ha. 

1994: Percent cover: pinegrass 55, Wheeler’s bluegrass 20, elk 

sedge 10, lupine 2; herbage production 600 kg/ha.

1997: Percent cover: pinegrass 70, Wheeler’s bluegrass 20, lupine 

10, elk sedge 10; herbage production 675 kg/ha.

1998: Percent cover: pinegrass 55, Wheeler’s bluegrass 20, lupine 

15, Scouler’s woolyweed 8; herbage production 500 kg/ha.

2001: Percent cover: pinegrass 55, Wheeler’s bluegrass 15, lupine 

15, Scouler’s woolyweed 5; herbage production 500 kg/ha.

2002: Percent cover: pinegrass 40, Scouler’s woolyweed 10, lupine 

10; herbage production 450 kg/ha. Pine seedlings top right. 
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

1995: Percent cover: pinegrass 40, Scouler’s woolyweed 10, lupine 

10; herbage production 500 kg/ha. Pine seedlings top right near log. 

1996: Percent cover: pinegrass 70, Wheeler’s bluegrass 20, 

Scouler’s woolyweed 5; herbage production 600 kg/ha.

1999: Percent cover: pinegrass 40, lupine 10, Scouler’s woolyweed 

5; herbage production 400 kg/ha. 

2000: Percent cover: pinegrass 50, Wheeler’s bluegrass 20, 

Scouler’s woolyweed 10, no lupine; herbage production 550 kg/ha.

2003: Percent cover: pinegrass 40, Scouler’s woolyweed 10, lupine 

10, Wheeler’s bluegrass 10; herbage production 400 kg/ha.

2004: Percent cover: pinegrass 45, Wheeler’s bluegrass 25, Scouler’s woolyweed 10, elk sedge 10; herbage production 450 kg/ha.
General TEchnical REport PNW-GTR-704

10

2005: View of the pine/pinegrass site after 27 years. The regenerating pines shown in 1983, 1992, 1995, and 2002 are just behind 

the end of the log and about 2 m tall after about 25 years. Root 

competition from dominant pines has greatly reduced height 

growth, which should be about 6 m on this site index of 23 m.

Difference in density of pinegrass, the dominant herb, is caused 

by variation in ash depth over the buried soil. The image for 1979 

shows less contrast because the drought limited height of pinegrass. 

2005: Percent cover: pinegrass 40, Wheeler’s bluegrass (seedheads) 20, elk sedge 10, Scouler’s woolyweed 8; herbage production 450 kg/ha. Pine seedlings at the top-right are now only 

saplings after 25 years. 

A crude estimate of herbage production may be obtained by 

multiplying total herbage cover by a factor of 6.2. For the example 

above: 40 + 20 + 10 + 8 = 78; 78 X 6.2 = 483 kg/ha.

Comments 

Over a 26-year period (data from table 1-BSPCF-ponderosa pine/pinegrass): 

• Pinegrass, the dominant species, varied from 35 to 55 percent cover, a 

1.5-fold difference, which was not affected by livestock utilization. This variation suggests that estimation of range condition by use of canopy cover is 

questionable.

• Sampling of vegetation to estimate range condition should consider 

methods that are sensitive to species presence as well as dominance. For example, lupine was measurable for canopy cover only 73 percent of the time, 

yet it was still rooted in the plant community. During good lupine growing 

conditions, it attained 25 to 35 percent canopy cover and produced heavy 

seeds enhancing herbage production. 

• Total herbage production averaged 520 kg/ha but varied from 300 to 675 kg/

ha, a 2.25-fold difference on the same good range condition site. Exercise caution when estimating allotment carrying capacity based on range condition. 

• Only pinegrass had measurable canopy cover 100 percent of the time. Four 

other species, lupine, Scouler’s woolyweed, elk sedge, and Wheeler’s bluegrass were evident only 65 to 75 percent of the time. They were 

present but not measurable for canopy cover or herbage production. This situation should be considered when describing vegetation characteristics for range 

condition guides.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

11

Table 1-BSPCF—Ponderosa pine/pinegrass. Yearly canopy cover by species and statistics on 

total yearly canopy cover, herbage production, and ratio of production to canopy cover

 Canopy cover by species codea

 Herb Herbage Ratio cover/ 

Year CARU LUCA HISC2 CAGE2 PONE2 NOTR2 ARCO9 cover production kg/ha

 

 Percent Percent kg/ha Ratio

1979 40 10 20 60 300 5.0

1980 50 25 5 25 2 10 95 550 5.8

1981 50 25 15 100 650 6.5

1982 40 20 2 20 10 5 80 450 5.6

1983 50 25 1 75 400 5.3

1984 55 30 20 105 600 5.7

1985 35 30 5 15 85 450 5.0

1987 40 25 20 85 500 5.9

1988 55 35 10 1 1 100 600 6.0

1989 45 25 20 90 500 5.6

1990 60 5 1 15 81 600 7.5

1991 45 20 5 1 10 5 90 600 6.7

1992 40 10 1 20 70 500 7.1

1993 45 15 5 10 10 90 675 7.5

1994 45 1 10 20 87 600 6.9

1995 40 10 10 60 500 8.3

1996 50 5 1 20 60 600 6.3

1997 50 10 5 10 20 95 675 7.1

1998 45 15 8 20 98 500 5.1

1999 40 10 5 60 400 6.7

2000 50 10 20 80 550 6.9

2001 55 15 5 15 90 500 5.6

2002 40 10 10 60 450 7.5

2003 40 10 10 10 70 400 5.7

2004 50 10 25 90 550 6.1

2005 40 18 8 10 30 83 450 5.1 

Mean 46.0 18.1 6.8 13.1 15.4 3.5 7.5 Mean 83.8 520.2 6.2

Count 26 19 18 18 17 2 2 SD 13.5 94.6 0.9

Percent 100 73 69 69 65 8 8 5% CI 5.2 36.4 0.4

Note: SD = standard deviation; CI = confidence interval.

a See “Species List: Codes” for plant code definitions.

Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

13

Ponderosa Pine/Bitterbrush/Idaho Fescue Site: 

Herbage Dominance and Production

This study was placed on ecology plot number 203 installed in 1957 to measure vegetation and soil attributes for 

development of range condition guides (USDA FS 1967b). It is located on the Lookout Mountain District, Ochoco 

National Forest, on the east edge of Big Summit Prairie. All sampling was done between August 1 and 4 each 

year starting in 1977 to the present.

1957: The ponderosa/bitterbrush/fescue community in 1957 with 

small, sapling sized ponderosa regeneration, hedged bitterbrush, 

and vigorous fescue. Color in the slide has faded over 45 years.

Soil is Mazama ash over basalt-derived residual soil. A 9-in finger 

spread was replaced by a meter tape for subsequent images. Total 

soil depth was 0.6 m. 

1978: Same stand in 1978 when this study was initiated. Pine 

saplings have only grown about 6 dm in 20 years. The area was 

underburned in spring 2002 when the log left rear of the meter 

board was consumed. A precommercial thinning was applied in 

2003.

1978: Idaho fescue is the dominant herb. The foreground individual has produced abundant seed stalks. Compare to following 

images. It was killed by the prescribed burn of 2002.
General TEchnical REport PNW-GTR-704

14

1979: No seedheads; percent cover: Idaho fescue 20, squirreltail 5, 

wheatgrass 5; herbage production 300 kg/ha.

1980: No seedheads; percent cover: fescue 15, wheatgrass 5, Ross 

sedge 2, squirreltail 2; herbage production 250 kg/ha.

1983: No seedheads; percent cover: fescue 15, wheatgrass 2, Ross 

sedge 2, pussytoes 2; herbage production 200 kg/ha.

1984: No seedheads; percent cover: fescue 15, Ross sedge 2, 

needlegrass 2, yarrow 1; herbage production 225 kg/ha.

1987: 50 percent seedheads; percent cover: fescue 15, wheatgrass 

8, needlegrass 3, junegrass 2; herbage production 250 kg/ha.

1988: No seedheads; percent cover: fescue 15, wheatgrass 2, 

squirreltail 2, Ross sedge 2; herbage production 200 kg/ha. 
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

15

1981: 60 percent seedheads; percent cover: fescue 25, wheatgrass 

7, needlegrass 2; herbage production 350 kg/ha.

1982: 10 percent seedheads; percent cover: fescue 25, wheatgrass 

2, lupine 5, pussytoes 2, herbage production 300 kg/ha.

1985: No seedheads; percent cover: fescue 20, Japanese brome 8 

(heads), squirreltail 5; herbage production 325 kg/ha.

1986: No seedheads, percent cover: fescue 12, wheatgrass 2, 

pussytoes 1, Ross sedge 1; herbage production 150 kg/ha.

1989: 20 percent seedheads; percent cover: fescue 18, wheatgrass 

2, squirreltail 3, bluegrass 2; herbage production 235 kg/ha.

1990: No seedheads; percent cover: fescue 20, wheatgrass 5, junegrass 2, Ross sedge 2; herbage production 300 kg/ha.
General TEchnical REport PNW-GTR-704

16

1991: 10 percent seedheads; percent cover: fescue 10, wheatgrass 

2, pussytoes 1, needlegrass 1; herbage production 175 kg/ha.

1992: No seedheads; percent cover: fescue 15, pussytoes 2, Ross 

sedge 2, squirreltail 2; herbage production 225 kg/ha.

1995: No seedheads; percent cover: fescue 12, wheatgrass 2, 

squirreltail 2, Ross sedge 2; herbage production 225 kg/ha. 

1996: No seedheads; percent cover: fescue 18, wheatgrass 2, 

squirreltail 4, Ross sedge 3; herbage production 300 kg/ha.

1999: 5 percent seedheads; percent cover: fescue 15, wheatgrass 3, 

squirreltail 2, needlegrass 2; herbage production 250 kg/ha.

2000: 10 percent seedheads; percent cover: fescue 18, wheatgrass 

2, Ross sedge 2, pussytoes 1; herbage production 250 kg/ha. 
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

17

1993: 10 percent seedheads; percent cover: fescue 20, wheatgrass 

3, Japanese brome 6, yarrow 2; herbage production 300 kg/ha.

1994: 40 percent seedheads; percent cover: fescue 20, wheatgrass 

10, yarrow 2, needlegrass 3; herbage production 350 kg/ha.

1997: 30 percent seedheads; percent cover: fescue 15, wheatgrass 

2, Japanese brome 3, yarrow 2; herbage production 250 kg/ha. 

1998: 10 percent seedheads; percent cover: fescue 18, wheatgrass 

4, needlegrass 1, pussytoes 1; herbage production 275 kg/ha. 

2001: 10 percent seedheads; percent cover: fescue 15, wheatgrass 

2, pussytoes 2, needlegrass 1; herbage production 225 kg/ha. 

The next few pages document a spring underburn 

and a precommercial thinning on this site. 
General TEchnical REport PNW-GTR-704

18

2002: The stand was underburned in spring 2002. Patchy pine 

saplings were not thinned. Single trees in fuel-loaded areas were 

killed. The log in left background of 1978 was consumed.

2002: Spring underburn. Fescue (front center) was killed (white 

ash); some unburned fescue are green.

2004: Fescue has recovered and has abundant seedheads. Stand 

density is now appropriate for this savanna ponderosa pine site 

with its low stockability.

2004: 100 percent seedheads; percent cover: fescue 25, wheatgrass 

1, Ross sedge 1, few species; herbage production 350 kg/ha.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

19

2003: The stand was precommercially thinned to adjust stocking 

level in fall 2002. Slash was untreated. Fescue has greened up 

since the underburn in 2002. 

2003: Precommercial thin, fall 2002. The cut pine sapling was 

only 5 cm diameter after 30 years.

2005: Some overstory trees have been harvested in the background. Fescue has several years accumulated dry foliage showing 

lack of livestock grazing. Most of the bitterbrush shown in 1957 

and 1978 is missing, presumably owing to underburning, increasing tree canopy, and utilization by ungulates. 

2005: 80 percent seedheads on older fescue; percent cover: fescue 

20, some young fescue, few species; herbage production 300 

kg/ha. 
General TEchnical REport PNW-GTR-704

20

2006: Little change is apparent since 2004. There is scant 

evidence of bitterbrush reestablishment. Herbage production is 

between 300 and 350 kg/ha. 

2006: 100 percent seedheads on all fescues; percent cover: fescue 

20, wheatgrass 2. The grey patch in the front center is killed fescue, but one corner is apparently alive. 

Comments 

Over a 27-year period (data from table 2-203EPF-Pine/fescue): 

• Seedheads were produced only 60 percent of the time. Abundant seedhead production, more than 50 percent of the bunchgrass plants flowering, only occurred 15 

percent of the time. Yet abundant seedhead production has been used as an indication of good vigor and a healthy plant community (Committee on Rangeland 

Classification 1994, Pellant et al. 2005). 

Good range condition means an end point in succession where the plant community is so competitive that earlier seral species are excluded (Committee on 

Rangeland Classification 1994, Pellant et al. 2005). How can maximum competition 

equate to maximum vigor and thus maximum seedheads? I feel they are not synonymous. Good condition has fewer seedheads than upward trend communities.

The precommercial thinning of 2002 reduced tree cover and root competition 

sufficiently to foster abundant seedhead production not seen in the previous 26 

years. 

• Herbage production averaged 262 kg/ha but varied from 150 to 350 kg/ha, a 2.25-

fold difference on the same good range condition site. Production seemed to increase following precommercial thinning. Pellant et al. (2005) considered herbage 

production a criteria for evaluating rangeland health.

• Color of fescue varied from greenish-gray to green over the years. Inclusion of 

dead, gray leaves and stems tends to reduce fescue palatability to ungulates. Thus 

differences in August color suggest variability in dates when forage is preferred implying that a flexible grazing management system might be beneficial for ungulates.

• Change in the plant community since precommercial thinning suggests an “upward range trend” shown by plant vigor and production. On forested rangeland, 
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

21

tree cover and competition can influence herbaceous vegetation at least as much as 

livestock. 

• Savanna pine sites are a transition from grassland or sagebrush to forest. Trees 

can barely become established and grow. This site is an example. Stockability is 

only 14 m2/ha (Hall 2004) for a site index of 19 m. Normal yield tables suggest 

an average of 40 m2/ha (Meyer 1938). Compare height of saplings between 1957 

and 2002: a period of 45 years, yet they are only 4 m tall, not 12 m (Meyer 1938). 

Saplings have stagnated and have not self-thinned. Thinning to low stand densities 

provides room for trees to grow and room for herbaceous vegetation to flourish. 

Table 2-203EPF—Ponderosa pine/Idaho fescue. Yearly canopy cover by species, plants with seedheads per 

year, and statistics on total yearly herbage production, canopy cover, and ratio of production to canopy cover

 Canopy cover by species codea Ratio 

 Herb Herbage cover/

Year FEID PSSPS ELELE CARO5 ANST2 ACOC9 BRJA ACMI2 Seedheads cover production kg/ha

 Percent Percent kg/ha Ratio

1979 20 5 5 30 300 10.0

1980 15 5 2 2 24 250 10.4

1981 25 7 2 60 34 350 10.3

1982 25 2 2 10 29 300 8.8

1983 15 2 2 2 21 200 9.5

1984 15 2 2 1 20 225 11.3

1985 20 5 8 33 325 9.8

1986 12 2 1 1 18 150 9.4

1987 15 8 3 50 28 250 8.9

1988 15 2 2 2 21 200 9.5

1989 18 2 3 20 23 235 10.3

1990 20 5 2 29 300 10.3

1991 10 2 1 1 10 14 175 12.5

1992 15 2 2 2 21 225 10.7

1993 20 3 6 2 10 31 300 9.7

1994 20 10 3 2 40 35 350 10.0

1995 12 2 2 2 18 225 12.5

1996 18 2 4 3 27 300 11.1

1997 15 2 3 2 30 22 250 11.4

1998 18 4 1 1 10 24 275 11.5

1999 15 3 2 2 5 22 250 11.4

2000 18 2 2 1 10 23 250 10.9

2001 15 2 2 1 10 20 225 11.3

2004 25 1 1 100 27 350 13.0

2005 20 11 80 31 300 9.6

Mean 17.4 3.4 3.0 1.9 1.5 1.9 5.7 1.7 XXX Mean 25.0 262 10.7

Count 25 21 9 12 8 8 3 4 15 SD 5.9 54.3 1.6

Percent 100 85 35 48 31 31 12 16 60 5% CI 2.3  21.3 0.63

Note: SD = standard deviation; CI = confidence interval.

a See “Species List: Codes” for plant code definitions. 

Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

23

Low Sagebrush/Bluebunch Wheatgrass Site: 

Herbage Dominance and Production

An original ecology plot, number 88, is the sampling location for this study. It was installed in 1959 to measure 

vegetation and soil attributes for development of range condition guides (USDA FS 1967c). The area had been 

sheep range that was converted to cattle range. It has not been grazed since 1950. It is located on the Emigrant 

Creek District, Malheur National Forest about 64-km north of Burns, Oregon. All herbage production sampling 

was done between August 1 and 4 each year since 1977 and is continuing. 

1959: The low sagebrush/bluebunch wheatgrass community in 

1959 with juniper slowly colonizing the site. The colonization is 

very slow as shown below and on the last pages of this section.

The soil is residual derived from flow andesite and is stony on the 

surface. Texture is stony silt loam. The 4-dm depth occurs in a 

500-mm precipitation zone supporting ponderosa pine. Because 

the shallow soil’s field capacity is exceeded, it becomes water 

logged in the winter and early spring apparently precluding pine 

establishment. Juniper occurs on fault lines.

1978: The first sampling season for this study showing little 

change in juniper density. Herbaceous vegetation is dominated 

by bluebunch wheatgrass. Bitterbrush occurs sporadically and is 

heavily hedged. Images were not available for 1986 and 2000.

1978: Percent cover: bluebunch wheatgrass 40, low sagebrush 8, 

Sandberg bluegrass 8, and squirreltail at 3. Wheatgrass did not 

produce seedheads, only bluegrass had heads. Grass was still fairly 

green the first of August; herbage production 350 kg/ha. 
General TEchnical REport PNW-GTR-704

24

1979: No seedheads; percent cover: wheatgrass 30, bluegrass 8, 

low sagebrush 9; herbage production 250 kg/ha.

1980: 20 percent seedheads on wheatgrass; percent cover: wheatgrass 45, bluegrass 7, low sagebrush 8; herbage production 350 kg/ha.

1983: No seedheads; percent cover: wheatgrass 35, bluegrass 8, 

squirreltail 2, low sagebrush 8; herbage production 300 kg/ha.

1984: 10 percent seedheads; percent cover: wheatgrass 30, bluegrass 

8, squirreltail 2, low sagebrush 7; herbage production 250 kg/ha.

1988: No seedheads; percent cover: wheatgrass 40, bluegrass 8, squirreltail 3, junegrass 2, low sagebrush 11; herbage production 350 kg/ha.1989: No seedheads; percent cover: wheatgrass 35, bluegrass 7, junegrass 1, phlox 1, low sagebrush 11; herbage production 325 kg/ha. 
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

25

1981: 60 percent seedheads; percent cover: wheatgrass 50, bluegrass 8, 

squirreltail 2, onion 2, low sagebrush 9; herbage production 500 kg/ha.

1982: No seedheads; percent cover: wheatgrass 45, bluegrass 6, 

onion 2, low sagebrush 8; herbage production 350 kg/ha.

1985: 10 percent seedheads; percent cover: wheatgrass 25, bluegrass 4, low sagebrush 8; herbage production 200 kg/ha. 1987: 10 percent seedheads; percent cover: wheatgrass 40, bluegrass 

8, junegrass 4, low sagebrush 10; herbage production 400 kg/ha. 

1990: 10 percent seedheads; percent cover: wheatgrass 50, bluegrass 8, squirreltail 8, needlegrass 5, low sagebrush 11; herbage 

production 600 kg/ha. 

1991: 20 percent seedheads; percent cover: wheatgrass 45, 

bluegrass 10, junegrass 3, low sagebrush 11; herbage production 

475 kg/ha. 
General TEchnical REport PNW-GTR-704

26

1992: No seedheads; percent cover: wheatgrass 45, bluegrass 10, 

squirreltail 8; low sagebrush 11; herbage production 475 kg/ha.

1993: 30 percent seedheads; percent cover: wheatgrass 35, bluegrass 10, junegrass 12, squirreltail 8, low sagebrush 10; herbage 

production 400 kg/ha.

1996: No seedheads; percent cover: wheatgrass 35, bluegrass 8, 

junegrass 2, squirreltail 4, low sagebrush 5; herbage production 

400 kg/ha.

1997: No seedheads; percent cover: wheatgrass 40, bluegrass 8, 

lomatium 2, low sagebrush 4; herbage production 425 kg/ha.

2001: 40 percent seedheads; percent cover: wheatgrass 50, bluegrass 

10, junegrass 6, low sagebrush 3; herbage production 550 kg/ha. 

2002: No seedheads; percent cover: wheatgrass 35, bluegrass 8, 

junegrass 4, low sagebrush 4; herbage production 350 kg/ha 
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

27

1994: 80 percent seedheads; percent cover: wheatgrass 55, bluegrass 10, squirreltail 8, low sagebrush 8; herbage production 525 

kg/ha.

1995: No seedheads; percent cover: wheatgrass 25, bluegrass 8, 

junegrass 2, squirreltail 2, low sagebrush 6; herbage production 

300 kg/ha.

1998: No seedheads; percent cover: wheatgrass 40, bluegrass 8, 

onion 4, junegrass 4, low sagebrush 4; herbage production 400 

kg/ha.

1999: No seedheads; percent cover: wheatgrass 35, bluegrass 6, 

oatgrass 2, low sagebrush 3; herbage production 325 kg/ha. 

2003: 10 percent seedheads; percent cover: wheatgrass 25, bluegrass 10, phlox 2, dandelion 1, low sagebrush 6; herbage production 250 kg/ha. 2004: 30 percent seedheads; percent cover: wheatgrass 20, bluegrass 12, phlox 2, low sagebrush 6; herbage production 200 kg/ha.
General TEchnical REport PNW-GTR-704

28

Comments

Over a 26-year period (table 3-088EPF-low sagebrush/bluebunch wheatgrass): 

• Seedheads were produced only 54 percent of the time. Bluegrass usually contributed most when seedhead density was low. Because best range condition suggests 

maximum competition, which excludes early seral species, one should question 

maximum seedhead production if it also implies maximum vigor (Committee on 

Rangeland Classification 1994, Pellant et al. 2005). 

My interpretation is that this is the best condition plant community for this site 

potential and would produce fewer seedheads than an upward trend community. 

• However, something seems to have happened starting in 2002. Cover of wheatgrass 

and herbage production decreased from an average of about 60 percent and 375 

kg/ha, to only 42 percent and 250 kg/ha, respectively. There is no evidence of livestock overgrazing; in fact, no evidence of grazing at all. I do not have an explanation for this change in the plant community. 

• Herbaceous canopy cover averaged 50 percent and varied from 29 to 83 percent, a 

2.9-fold difference. This yearly variation clearly limits canopy cover as a means for 

evaluating range condition. When observer variability is considered, the 16 to 44 

percent reported by Coles-Ritchie et al. (2004) further reduces the value of canopy 

cover.

• A crude estimation of herbage production may be obtained by multiplying total 

herbage cover by a factor of 7.3. For the 2005 example above: 22 + 14 + 3 = 39; 39 

X 7.3 = 285 kg/ha. Low sagebrush 7 percent cover is not counted as contributing to 

herbage. 

• Herbage production varied from 200 to 600 kg/ha over the 26-year period, averaging 367 kg/ha, a threefold difference. Production less than 275 kg/ha occurred five 

times (20 percent). This yearly variation might be considered in livestock manage2005: Juniper, low sagebrush, some bitterbrush, wheatgrass, and 

Sandberg bluegrass as it looks after 26 years. Note the decline 

in wheatgrass since 2002 and compare this image with the 1978 

image.

2005: No seedheads; percent cover: wheatgrass 22, bluegrass 14, 

needlegrass 3, low sagebrush 7; herbage production 250 kg/ha.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

29

ment. Pellant et al. (2005) considered herbage production as a criteria for evaluating 

rangeland health. These data suggest it should be used with caution. 

• Color of wheatgrass during the first four days of August varied from totally dry 

(1979) to bright green (1993) with all degrees of curing in between. Because curing 

of vegetation affects its palatability, this seasonal variation might be considered in 

livestock management.

Table 3-088EPF—Low sagebrush/bluebunch wheatgrass. Yearly canopy cover by species, plants with 

seedheads per year, and statistics on total yearly herbage canopy cover, herbage production, and ratio of 

production to herbage canopy cover 

 Canopy cover by species codea Ratio

 Herb Herbage cover/

Year PSSPS POSE ELELE KOMA ACOCO ALAC4 PHDO3 ARAR8 Seedheads cover production kg/ha

 Percent Percent kg/ha Ratio

1978 40 8 5 8 10 51 350 6.7

1979 30 6 8 34 250 7.3

1980 45 6 7 10 51 350 6.9

1981 50 8 2 2 7 60 60 500 8.3

1982 45 6 2 8 53 350 6.6

1983 35 8 2 8 45 300 6.7

1984 30 8 2 7 10 40 250 6.3

1985 25 4 8 10 29 200 6.9

1987 40 8 4 10 10 52 400 7.7

1988 40 8 2 11 50 350 7.0

1989 35 7 3 1 11 46 325 7.1

1990 50 8 8 5 11 10 71 600 8.5

1991 45 10 3 11 20 58 475 8.2

1992 45 10 8 11 63 475 7.5

1993 35 10 8 12 10 30 65 400 6.1

1994 55 10 8 10 8 80 83 525 6.3

1995 25 8 2 2 6 37 300 8.1

1996 35 8 4 2 5 49 400 8.2

1997 40 8 4 48 425 8.9

1998 40 8 4 3 4 55 400 7.3

1999 35 6 3 41 325 7.9

2001 50 10 6 3 40 66 550 8.3

2002 35 8 4 4 47 350 7.4

2003 25 10 2 6 10 37 250 6.6

2004 20 12 2 6 30 34 200 5.9

2005 22 14 3 7 13 39 250 6.4

Mean 37.4 8.3 4.7 4.7 4.0 2.3 1.7 7.4 XXX Mean 50.2 367.3 7.3

Count 26 26 10 11 2 3 3 26 14 SD 12.7 107.0 0.8

Percent 100 100 38 42 8 11 11 100 54 5% CI 4.9 41.1 0.3

Note: SD = standard deviation; CI = confidence interval. a See “Species List: Codes” for plant code definitions.

Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

31

Rigid Sagebrush Scabland Site: 

Herbage Dominance and Production

This site was selected in 1960 on which to measure vegetation and soil characteristics for developing range condition guides (USDA FS 1963). It is located on the Lookout Mountian District, Ochoco National Forest on the east 

edge of Big Summit Prairie shown in the background below left. All sampling was done between August 1 and 4 

each year from 1977 to the present.

1960: The rigid sagebrush scabland site sampled for range 

condition guides. It is located within the forest zone supporting 

ponderosa pine, Douglas-fir and grand fir. Scabland is characterized by very shallow soils shown at the right, which preclude tree 

establishment.

Soil is derived from recent andesite lava flows, and is characteristically only 1.5 to 3 dm deep. Precipitation is enough to cause water 

logging during much of the winter, which limits plant community 

diversity. 

1977: The site at the start of herbage production sampling. It is 

characterized by a desert pavement of gravel and rigid sagebrush, 

Sandberg bluegrass, pipe clover, and oatgrass, all capable of 

surviving saturated soils and frost heaving. Site characteristics 

are shown at the end of this section. Images were not available for 

1986 and 1988.

1977: 80 percent seedheads; percent cover: bluegrass 10, pipe 

clover 6, lomatium 7, oatgrass 6, rigid sage 4; herbage production 

150 kg/ha. 
General TEchnical REport PNW-GTR-704

32

1978: 40 percent seedheads; percent cover: bluegrass 10, pipe 

clover 5, lomatium 8, oatgrass 5, sagebrush 5; herbage production 

125 kg/ha.

1979: No seedheads; percent cover: bluegrass 10, pipe clover 4, lomatium 7, oatgrass 4, sagebrush 6; herbage production 125 kg/ha.

1982: 80 percent seedheads; percent cover: bluegrass 10, pipe clover 5, lomatium 6, oatgrass 6, wheatgrass 3, sagebrush 7; herbage 

production 200 kg/ha.

1983: 100 percent seedheads; percent cover: bluegrass 12, pipe 

clover 6, lomatium 6, oatgrass 7, wheatgrass 3, sagebrush 7; herbage production 125 kg/ha.

1987: No seedheads; percent cover: bluegrass 9, pipe clover 4, lomatium 6, oatgrass 6, wheatgrass 1, sagebrush 9; herbage production 

125 kg/ha.

1989: No seedheads; percent cover: bluegrass 9, pipe clover 3, 

lomatium 5, oatgrass 4, wheatgrass 1, sagebrush 9; herbage production 125 kg/ha.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

33

1980: No seedheads; percent cover: bluegrass 8, pipe clover 4, lomatium 6, oatgrass 4, sagebrush 6; herbage production 100 kg/ha1981: 50 percent seedheads; percent cover: bluegrass 8, pipe 

clover 4, lomatium 6, oatgrass 6, sagebrush 6; herbage production 

175 kg/ha.

1984: 100 percent seedheads; percent cover: bluegrass 12, pipe 

clover 6, lomatium 8, oatgrass 7, wheatgrass 3, sagebrush 8, herbage production 200 kg/ha.

1985: 80 percent seedheads; percent cover: bluegrass 10, pipe 

clover 4, lomatium 9, oatgrass 6, sagebrush 8; herbage production 

125 kg/ha.

1990: No seedheads; percent cover: bluegrass 9, pipe clover 3, 

lomatium 4, oatgrass 4, wheatgrass 1, sagebrush 9; herbage production 125 kg/ha. 

1991: No seedheads; percent cover: bluegrass 9, pipe clover 3, 

lomatium 4, oatgrass 3, wheatgrass 1, sagebrush 9; herbage production 100 kg/ha.
General TEchnical REport PNW-GTR-704

34

1992: 30 percent seedheads; percent cover: bluegrass 9, pipe clover 3, lomatium 4, oatgrass 3, wheatgrass 2, sagebrush 9; herbage 

production 170 kg/ha.

1993: 70 percent seedheads; percent cover: bluegrass 9, pipe clover 3, lomatium 3, oatgrass 3, wheatgrass 1, sagebrush 10; herbage 

production 110 kg/ha.

1996: 50 percent seedheads; percent cover: bluegrass 8, pipe 

clover 3, lomatium 4, oatgrass 3, sagebrush 10; herbage production 

75 kg/ha.

1997: 50 percent seedheads; percent cover: bluegrass 8, pipe 

clover 3, lomatium 3, oatgrass 3, sagebrush 11; herbage production 

150 kg/ha.

2000: No seedheads; percent cover: bluegrass 5, pipe clover 2, lomatium 2, oatgrass 2, sagebrush 12; herbage production 75 kg/ha.2001: 80 percent seedheads; percent cover: bluegrass 5, pipe clover 2, lomatium 2, oatgrass 2, sagebrush 12; herbage production 

100 kg/ha.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

35

1994: No seedheads; percent cover: bluegrass 9, pipe clover 4, 

lomatium 4, oatgrass 3, wheatgrass 1, sagebrush 10; herbage production 150 kg/ha.

1995: 20 percent seedheads; percent cover: bluegrass 9, pipe clover 3, lomatium 3, oatgrass 3, wheatgrass 1, sagebrush 10; herbage 

production 125 kg/ha.

1998: 30 percent seedheads; percent cover: bluegrass 9, pipe 

clover 3, lomatium 3, oatgrass 3, sagebrush 11; herbage production 

125 kg/ha.

1999: No seedheads; percent cover: bluegrass 8, pipe clover 2, lomatium 2, oatgrass 3, sagebrush 11; herbage production 100 kg/ha.

2002: No seedheads; percent cover: bluegrass 6, pipe clover 2, 

lomatium 2, oatgrass 2, sagebrush 12; herbage production 100 

kg/ha.

2003: No seedheads; percent cover: bluegrass 6, pipe clover 2, 

lomatium 2, oatgrass 2, sagebrush 13; herbage production 100 

kg/ha.
General TEchnical REport PNW-GTR-704

36

Comments

Over a 27-year period (table 4-045EPF-rigid sagebrush/scabland):

• Seedheads, limited primarily to bluegrass, were produced only 59 percent of the 

time. Lack of abundant seedheads over the years suggests a plant community in 

near maximum competition and thus full occupancy of the site. Pellant et al. (2005), 

on the other hand, considered seedhead production one criteria for evaluating 

rangeland health. These data suggest it should be used with caution.

• Herbage production varied from 75 to 225 kg/ha averaging 131 kg/ha, a threefold 

difference. A crude estimation of herbage production may be obtained by multiplying herbage cover by a factor of 6.3. For the 2005 example above: 9 + 4 + 3 + 3 = 

19; 19 X 6.3 = 120 kg/ha. Sagebrush cover is not counted as herbage. Pellant et al. 

(2005) considered production as another element in evaluating rangeland health. 

Again it should be used with caution. 

• All herbaceous vegetation was dry by August 1. Shallow soil and lack of precipitation after the middle of June preclude active growth. However, the deciduous rigid 

sagebrush is quite palatable to deer, elk, cattle, and sheep. Note the hedged appearance. 

Ungulate use during wet soil periods can damage the biological crust by trampling.

Fortunately, insufficient herbage production generally limits heavy use. 

2005: The rigid sagebrush scabland after 27 years. Rigid sagebrush seems a little denser, and the pines in the background have 

grown. This is what “80 percent seedheads” looks like!

2005: 80 percent seedheads; percent cover: bluegrass 9, pipe 

clover 4, lomatium 3, oatgrass 3, sagebrush 12; herbage production 

125 kg/ha.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

37

Soil is saturated with water during winter and early spring. 

The change from saturated to summer bone dry seriously limits 

the variety of plant species capable of competing on this site. 

Revegetation with domestic species is not possible. It also limits 

hunters in the fall. They may drive out on frozen soil in early 

morning only to return in the evening to find their vehicle rim 

deep in mud.

Frost heaving during saturated soil conditions is common. Water 

freezes at night and then thaws during the day. The expanding 

ice crystals push gravels out of the top 1 to 2 in of soil and deposits them on the soil surface, a condition resulting in a “desert 

pavement.” The “A” horizon is vesicular as a result of frost heaving (Springer 1958). The gravel, in conjunction with microbiotic 

plants, successfully protect the soil surface (Belnap et al. 2001). 

Scabland lichen-encrusted rocks with a biological soil crust successfully protects the soil surface. This is the primary indication 

of “good range condition” as vascular vegetation cannot protect 

the soil (Belnap et al. 2001). 
General TEchnical REport PNW-GTR-704

38

Table 4-045EPF—Rigid sagebrush scabland. Yearly canopy cover by species, plants with seedheads 

per year, and statistics on total yearly herbage production, canopy cover, and ratio of production to 

canopy cover

 Canopy cover by species codea Ratio

 Herb Herbage cover/

Year POSE TRMA3 LOGR DAUN PSSPS ARRI2 Seedheads cover production kg/ha

 Percent Percent kg/ha Ratio

1977 10 6 7 6 4 50 29 150 5.2

1978 10 5 8 5 5 40 28 125 4.5

1979 10 4 7 4 6 25 125 5.1

1980 8 4 6 4 6 22 100 4.5

1981 8 4 6 6 6 50 24 175 7.3

1982 10 5 6 6 3 7 80 30 200 6.7

1983 12 6 6 7 3 7 100 31 225 7.2

1984 12 6 8 7 3 8 100 36 200 5.6

1985 10 4 9 6 8 80 29 125 4.3

1987 9 4 6 6 1 9 26 125 4.8

1989 9 3 5 4 1 9 22 125 5.6

1990 9 3 4 4 1 9 21 125 5.9

1991 9 3 4 3 1 9 20 100 5.1

1992 9 3 4 3 2 9 30 21 170 8.1

1993 9 3 3 3 1 10 70 19 110 5.8

1994 9 4 4 3 1 10 21 150 7.1

1995 9 3 3 3 1 10 20 19 125 6.6

1996 8 3 4 3 10 50 18 75 4.2

1997 8 3 3 3 10 50 17 150 8.8

1998 9 3 3 3 11 30 18 125 6.9

1999 8 2 2 3 11 15 100 6.7

2000 5 2 2 2 12 11 75 6.8

2001 5 2 2 2 12 80 11 100 9.1

2002 6 2 2 2 12 12 100 8.3

2003 6 2 2 2 13 12 100 8.3

2004 10 4 4 4 13 20 22 125 5.7

2005 9 4 3 3 12 80 19 125 6.6

Mean 8.7 3.6 4.6 3.9 1.6 9.2 XXX Mean 21.4 130.7 6.3

Count 27 27 27 27 11 27 16 SD 6.4 37.1 1.4

Percent 100 100 100 100 41 100 54 5% CI 2.5 14.0 0.5

Note: SD = standard deviation; CI = confidence interval.

a See “Species Lists: Codes” for plant definitions.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

39

Summary

Canopy Cover

Over a 27-year period, canopy cover varied as follows: BSPCF pine/pinegrass a 

2.2-fold difference, 203EPF pine/fescue 2.3-fold, 088EPF low sagebrush/wheatgrass three-fold, and 045EPF rigid sagebrush scabland at a threefold difference. 

Reasons for this wide variation are open to speculation because the sites had not 

been grazed. I suspect growing conditions. 

Herbage cover fluctuated widely bringing into question the use of canopy cover 

as a measure of range condition. This fluctuation coupled with observer variability 

in estimating canopy cover (Coles-Ritchie et al. 2004) leads me to look for other 

vegetation measurements for characterizing range condition guides. 

Ratio of Cover to Productivity

This study was designed to evaluate yearly changes in shrub and herbaceous cover 

and herbage productivity. Table 5 summarizes the relationship between percentage 

of herbage canopy cover and kilograms per hectare herbage production. Herbage 

production in kilograms per hectare was divided by total herbage percentage of 

canopy cover to calculate a ratio between the two. The four ratios and their 5 percent confidence intervals are shown in table 5. For each site, the confidence interval 

was calculated as a percentage of the ratio mean. These ratios are then compared 

for 50-percent herbage canopy cover. For example, the BSPCF ratio is 6.2: 6.2 X 50 

percent = 310 kg/ha estimated production. 

One ratio stands out as significantly different, 203EPF pine/bitterbrush/fescue, 

at 10.7. I suspect the dense, fine leaves of fescue contribute to increased weight per 

square decimeter of canopy cover. 

Image Evaluation

Interpretation of color images greatly enhanced this investigation. Because season 

of sampling was constant, August 1 to 4, differences in greenness of the vegetation could be evaluated. Pinegrass was reasonably consistent in color. However 

wheatgrass and fescue varied from cured brown to bright green reflecting major 

differences in phenological development and thus nutritive value and palatability to 

animals. 

Careful scrutiny of images also revealed items not measured in this study. 

Tree regeneration and growth was one. The BSPCF ponderosa pine/pinegrass is an 

example. In 1979, a pine seedling was present next to the meter board between 6 

and 8 dm. By 1982 it was gone. On the same site, a pine had become established in 

1982 at the top center of the image. By 1992 it had grown to 1 cm in diameter, and 
General TEchnical REport PNW-GTR-704

40

by 2004 it was 2 cm diameter. In 22 years, this sapling had only grown about 2 cm 

in diameter. 

Another illustration of tree growth is shown in 203EPF ponderosa pine/bitterbrush/fescue. Saplings in 1957 were about 1 m in height. By 1978, 21 years later, 

they were only 2 m tall. And by 2002, 45 years later, they were about 4 m tall. They 

should be 12 m in height according to normal yield tables (Meyer 1938). They were 

stagnated, growing at about 1 cm/decade in diameter. Years 2003 to 2006 document 

upward range trend resulting from tree thinning.

Erosion may also be appraised by use of photomonitoring. The low movement of rocks shown in both 088EPF low sagebrush/wheatgrass and 045EPF rigid 

sagebrush/ scabland suggests no accelerated erosion. 

Table 5—Statistical summary of the ratio between herbage cover and kilograms 

per hectare herbage production illustrated for 50 percent canopy cover

 CI % of Herbage at 50% 5% CI variation

Site Ratio 5% CI mean canopy cover in production

 Kilograms per hectare

BSPCF 6.2 0.4 6 310 290 to 330

203EPF 10.7 0.6 6 535 505 to 565

088EPF 7.3 0.3 4 365 350 to 380

045EPF 6.3 0.5 8 315 290 to 340

Note: CI = confidence interval.
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

41

Species List: Common Names

Common name Scientific name	 Code

Arnica Arnica cordifolia Hook. ARCO9

Bluebunch wheatgrass Pseudoroegneria spica ssp. spicata (Pursh) A. Love PSSPS

(old name) Agropyron spicatum (Pursh) Scribn. & J.G. Sm. (AGSP)

Dandelion Nothocalais troximoides (Gray) Greene NOTR2

(old name) Microseris troximoides Gray (MITR5)

Douglas-fir Pseudotsuga menziesii var. glauca (Beissn.) Franco PSMEG

Elk sedge Carex geyeri Boott CAGE2

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

Idaho fescue Festuca idahoensis Elmer FEID

Japanese brome Bromus japonicus Thunb. ex Murr. BRJA

Junegrass Koeleria macrantha (Ledeb.) J.A. Schultes KOMA

(old name) Koeleria cristata auct. p.p., non Pers. (KOCR)

Juniper Juniperus occidentalis Hook. JUOC

Lomatium Lomatium grayi (Coult & Rose) Coult & Rose LOGR

Low sage Artemisia arbuscula Nutt. ARAR8

Lupine Lupinus caudatus Kellog LUCA

Needlegrass Achnatherum occidentale Barkworth ssp. occidentale ACOCO

(old name) Stipa occidentalis Thurb. ex S. Wats (STOC2)

Oatgrass Danthonia unispicata (Thurb.) Munro ex Macoun DAUN

Onion Allium acuminatum Hook. ALAC4

Phlox Phlox douglasii Hook. PHDO3

Pinegrass Calamagrostis rubescens Buckl. CARU

Pipe clover Trifolium macrocephalum (Pursh) Poir. TRMA3

Ponderosa pine Pinus ponderosa P.& C. Lawson PIPO

Pussytoes Antennaria stenophylla (Gray) Gray ANST2

Rigid sage Artemisia rigida (Nutt.) Gray ARRI2

Ross’ sedge Carex rossii Boott CARO5

Sandberg bluegrass Poa secunda J. Presl POSE

Scouler’s woollyweed Hieracium scouleri Hook. HISC2

Squirreltail Elymus elymoides (Raf.) Swezey spp. elymoides (Raf.) ELELE

(old name) Sitanion hystrix (Nutt.) J.G. Sm. (SIHY)

Wheatgrass Pseudoroegneria spicata ssp. spicata (Pursh) A. Love PSSPS

(old name) Agropyron spicatum (Pursh) Scrib. & J.G. Sm. (AGSP)

Wheeler’s bluegrass Poa nervosa (Hook.) Vasey PONE2

Yarrow Achillea millefolium L. ACMI2
General TEchnical REport PNW-GTR-704

42

Species List: Codes

Code	 	 Scientific name Common name 

ACMI2 Achillea millefolium L. Yarrow

ACOCO Achnatherum occidentale ssp. occidentale Barkworth Needlegrass

ALAC4 Allium acuminatum Hook. Onion

ARAR8 Artemisia arbuscula Nutt. Low sage

ARCO9 Arnica cordifolia Hook. Arnica

ARRI2 Artemisia rigida (Nutt.) Gray Rigid sage

ANST2 Antennaria stenophylla (Grey) Grey Pussytoes

BRJA Bromus japonicus Thunb. ex Murr. Japanese brome

CAGE2 Carex geyeri Boott Elk sedge

CARO5 Carex rossii Boott Ross’ sedge

CARU Calamagrostis rubescens Buckl. Pinegrass

DAUN Danthonia unispicata (Thurb) Munro ex Macoun Oatgrass

ELELE Elymus elymoides spp. elymoides (Raf.) Swezey Squirreltail

FEID Festuca idahoensis Elmer Idaho fescue

HISC2 Hieracium scouleri Hook. Scouler’s woollyweed

KOMA Koeleria macrantha (Ledeb.) J.A. Schultes Junegrass

LOGR Lomatium grayi (Coult & Rose ) Coult & Rose Lomatium

LUCA Lupinus caudatus Kellog Lupine

NOTR2 Nothocalais troximoides (Gray) Greene Dandelion

PHDO3 Phlox douglasii Hook. Phlox

PONE2 Poa nervosa (Hook.) Vasey Wheeler’s bluegrass

POSE Poa secunda J. Presl Sandberg bluegrass

PSSPS Pseudoroegneria spica ssp. spicata (Pursh) A. Love Bluebunch wheatgrass

TRMA3 Trifolium macrocephalum (Pursh) Poir. Pipe clover

English Equivalents

When you have: Multiply by: To get:

Centimeters (cm) .394 Inches

Decimeters (dm) 3.94 Inches

Meters (m) 3.28 Feet

Kilograms per hectare (kg/ha) .89 Pounds per acre

Millimeters (mm) .0394 Inches

Square meters (m2) 1.2 Square yards

Square meters per hectare (m2/ha) 4.37 Square feet per acre
Variation in Shrub and Herb Cover and Production on Ungrazed Pine and Sagebrush Sites in Eastern Oregon

43

Literature Cited

Belnap, J.; Rosentreter, R.; Leonard, S.; Kaltenecker, J.H.; Williams, J.; Eldridge, 

D. 2001. Biological soil crusts: ecology and management. Technical Reference 1730–2. 

Denver, CO: U.S. Department of the Interior, Bureau of Land Management, National 

Science and Technology Center, Information and Communications Group. 110 p.

Coles-Ritchie, M.C.; Henderson, R.C.; Archer, E.K.; Kennedy, C.; Kershner, J.L. 

2004. Repeatability of riparian vegetation samplings methods: How useful are these 

techniques for broad-scale, long-term monitoring? RMRS-GTR-138. Fort Collins, CO: 

U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 

18 p.

Committee on Rangeland Classification. 1994. Rangeland health: new methods to 

classify, inventory, and monitor rangelands. Washington, DC: Board on Agriculture, 

National Research Council, National Academy Press. 182 p.

Hall, F.C. 2002. Photo point monitoring handbook: Part A—Field procedure; Part B—

Concepts and analysis. Gen. Tech. Rep. PNW-GTR-526. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station. 134 p. 

Hall, F.C. 2004. The concept and application of growth basal area: a forestland 

stockability index. R6 Ecol. Tech. Pap. 007-89. Portland, OR: U.S. Department of 

Agriculture, Forest Service, Pacific Northwest Region. 95 p. slide rule.

Meyer, W.H. 1938. Yield of even-aged stands of ponderosa pine. Tech. Bull. 630. 

Washington, DC: U.S. Department of Agriculture. 59 p.

Parker, K.W.; Harris, R.W. 1959. The 3-step method for measuring condition and 

trend of forest ranges; a resume of its history, development, and use. In: Techniques 

and methods of measuring understory vegetation—a symposium. Tifton, GA: U.S. 

Department of Agriculture, Forest Service, Southern Forest Experiment Station and 

Southeast Forest Experiment Station. 174 p.

Pellant, M.; Shaver, P.; Pyke, D.A.; Herrick, J.E. 2005. Interpreting indicators of 

rangeland health, version 4. Tech. Ref. 1734–6, BLM/WO/ST-001001 + 1734/REV05. 

Denver, CO: U.S. Department of the Interior, Bureau of Land Management, National 

Science and Technology Center. 95 p. 

Reppert, J.N.; Francis, R.E. 1973. Interpretation of trend in range condition from 

3-step data. Res. Pap. RM-103. Fort Collins, CO: U.S. Department of Agriculture, 

Forest Service, Rocky Mountain Forest and Range Experiment Station. 15 p. 
General TEchnical REport PNW-GTR-704

44

Springer, M.E. 1958. Desert pavement and vesicular layer of some soils of the desert of the 

Lahontan Basin, Nevada. Soil Science Society of America Proceedings. 22: 63–66.

U.S. Department of Agriculture, Forest Service [USDA FS 1963]. Condition and trend 

standard: shrub and non-shrub scablands. Oregon National Forests, Region 6. Form R6-

2210-49. 1963. Portland, OR: Pacific Northwest Region. 6 p. On file with: Frederick C. 

Hall, PMB 454, 1521 N Jantzen, Portland, OR 97217-8100.

U.S. Department of Agriculture, Forest Service [USDA FS 1967a]. Range condition 

standard: mixed conifer–Calamagrostis–Carex. Blue Mountains, Region 6. Form R6-

2210-53. 1967. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Region. 10 p. On file with: Frederick C. Hall, PMB 454, 1521 N Jantzen, 

Portland, OR 97217-8100.

U.S. Department of Agriculture, Forest Service [USDA FS 1967b]. Range condition 

standard: Pinus ponderosa–Festuca–Agropyron. Blue Mountains. Region 6. Form R6-

2210-51. 1967. Portland, OR: Pacific Northwest Region. 8 p. On file with: Frederick C. 

Hall, PMB 454, 1521 N Jantzen, Portland, OR 97217-8100.

U.S. Department of Agriculture, Forest Service [USDA FS 1967c]. Range condition 

standard: Artemisia–Agropyron–Festuca, Blue Mountains, Region 6. Form R6-2210-52. 

1967. Portland, OR: Pacific Northwest Region. 8 p. On file with: Frederick C. Hall, PMB 

454, 1521 N Jantzen, Portland, OR 97217-8100.
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