A Field Guide for Selecting the Most 

Appropriate Treatment in Sagebrush and 

Piñon-Juniper Ecosystems 

in the Great Basin

Evaluating Resilience to Disturbance and Resistance to Invasive 

Annual Grasses, and Predicting Vegetation Response

Richard F. Miller, Jeanne C. Chambers, and Mike Pellant

United States 

Department of 

Agriculture

Forest Service

Rocky Mountain 

Research Station

General Technical

 Report RMRS-GTR-322

June 2014

Cool and dry 

mountain big 

sagebrush—

Reference State

Warm and dry 

Wyoming big 

sagebrush—

Invaded State
Miller, Richard F.; Chambers, Jeanne C.; Pellant, Mike. 2014. A field guide for selecting the most appropriate 

treatment in sagebrush and piñon-juniper ecosystems in the Great Basin: Evaluating resilience to 

disturbance and resistance to invasive annual grasses, and predicting vegetation response. Gen. Tech. 

Rep. RMRS-GTR-322. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station. 66 p.

Abstract

This field guide identifies seven primary components that largely determine resilience to disturbance, as 

well as resistance to invasive grasses and plant succession following treatment of areas of concern. The 

primary components are (1) characteristics of the ecological site, (2) current vegetation prior to treatment, 

(3) disturbance history, (4) type, timing, and severity of the treatment, (5) post-treatment weather, (6) posttreatment management, especially grazing, and (7) monitoring and adaptive management. A series of key 

questions and a set of tools are provided to assess these primary components. This assessment is designed to 

allow field personnel to (1) evaluate resilience to disturbance and resistance to invasive annual grass for an area 

of concern, (2) predict the potential successional pathways, and (3) then select the most appropriate treatment, 

including the need for seeding. An evaluation score sheet is included for rating resilience to disturbance and 

resistance to invasive annual grasses and the probability of seeding success.

Keywords: restoration, resilience, resistance, succession, sagebrush, prescribed fire, mechanical treatment, 

piñon, juniper

Authors 

Richard F. Miller, Professor Emeritus of Range and Fire Ecology, Eastern Oregon Agricultural Research Center, 

Oregon State University, Corvallis, Oregon.

Jeanne C. Chambers, Research Ecologist, USDA Forest Service, Rocky Mountain Research Station, Reno, 

Nevada.

Mike Pellant, Rangeland Ecologist, Bureau of Land Management, Boise, Idaho.

You may order additional copies of this publication by sending your 

mailing information in label form through one of the following media. 

Please specify the publication title and series number.

Publishing Services

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FAX (970) 498-1212

E-mail rschneider@fs.fed.us

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Mailing address Publications Distribution

Rocky Mountain Research Station

240 West Prospect Road

Fort Collins, CO 80526
Acknowledgments

We sincerely thank all of the reviewers who commented on the manuscript and Eugénie MontBlanc for assisting 

with manuscript coordination. We also acknowledge the Sagebrush Steppe Treatment Evaluation Project (www.

sagestep.org) for increasing our understanding of vegetation treatments in these ecosystems. The field guide 

was funded by the Great Basin Fire Science Delivery Project, which is part of the Joint Fire Science Program, 

Knowledge Exchange Consortia, USDA Forest Service, Rocky Mountain Research Station, and Bureau of Land 

Management.
Contents

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

Key Questions Addressing Each of the Seven Primary Components...... 10

1-Ecological Site Characteristics .................................................................................10

2-Current Vegetation....................................................................................................17

3-Disturbance History ..................................................................................................23

4-Treatment Type and Severity....................................................................................23

5-Pre- and Post-treatment Weather.............................................................................26

6-Post-treatment Grazing.............................................................................................27

7-Monitoring and Adaptive Management .....................................................................29

Selecting the Most Appropriate Treatment Method..................................... 30

Selecting Treatment Areas ............................................................................. 36

Key References ............................................................................................... 37

Literature Cited................................................................................................ 38

Appendices

1-Primary components and attributes that influence resilience and 

resistance to annual grasses......................................................................... 41

2-Example of elevation breaks and plant indicators for soil temperature 

regimes in two MLRAs................................................................................... 42

3-Family names—what they tell you about the soil moisture/temperature 

regimes, depth, and texture........................................................................... 43

4-Characteristics of post- vs. pre-settlement woodlands .................................. 45

5-Post-burn indicators of fire severity................................................................ 49

6-State and transition models for five generalized big sagebrush 

ecological sites .............................................................................................. 50

7-Examples of states, phases, and transitions following prescribed fire 

or mechanical treatment................................................................................ 56

8-Evaluation sheet for rating resilience and resistance and probable 

seeding success for areas of concern........................................................... 60

9-Definitions ...................................................................................................... 65
One of the most challenging roles of a resource manager is conducting vegetation treatments across broad heterogeneous landscapes. In the Great Basin 

and Columbia River Plateau regions, a primary focus of vegetation treatments 

is on reducing woody species (shrubs and/or trees) to (1) reduce fuel loads 

and thus fire severity and extent, (2) increase perennial herbaceous species, 

which largely determine resilience to disturbance (recovery potential) and resistance to invasive annuals, (3) decrease the longer term risk of conversion 

to invasive annuals, and (4) maintain watershed integrity. Key elements of 

successful vegetation treatments designed to meet these objectives are the 

ability to evaluate an area’s resilience to disturbance or treatment, such as tree 

removal and resistance to invasive annual grasses, and to predict potential posttreatment successional pathways. This requires identifying and understanding the primary components and ecological site characteristics that determine 

resilience to management treatments and resistance to invasive annuals and 

that drive plant successional pathways.

This field guide is designed to enhance the ability of managers to identify and 

evaluate these primary components and to effectively meet management 

objectives in sagebrush and piñon and/or juniper ecosystems when those objectives include increasing or restoring resilience to disturbances including 

wildfires and stressors like climate change, and resistance to invasive annual 

grasses for areas of concern. Resilient ecosystems have the capacity to regain

their fundamental structure, processes, and functioning following disturbance, 

stressors, and management treatments. The resilience of an ecosystem is determined by its environmental characteristics and ecological conditions such 

as current vegetation, and reflects its recovery potential. Resistant ecosystems have the ability to retain their fundamental structure, processes, and 

functioning (or remain largely unchanged) despite disturbance and stressors. 

The resistance of an ecosystem to invasive annual grasses is a function of the 

environmental and ecological characteristics of an ecosystem that limits the 

population growth and expansion of the invasive species. Ecosystems that are 

both resilient and resistant provide valuable ecosystem services such as clean 

air, water, forage, and wildlife habitat.

Introduction

USDA Forest Service RMRS-GTR-322. 2014 1
2 USDA Forest Service RMRS-GTR-322. 2014

Purpose

The field guide provides a framework for evaluating potential treatment areas 

within sagebrush and piñon pine and/or juniper ecosystems in the Great Basin 

and Columbia River Plateau that are being considered for vegetation management treatments. This framework helps managers evaluate the following 

characteristics of a potential treatment area:

1. Resilience or potential recovery following vegetation treatments such as 

prescribed fire and mechanical treatments;

2. Resistance to invasive annual grasses and the risk of increases in invasive 

annual grasses following vegetation treatments;

3. Likely plant successional pathways following vegetation treatments; and

4. The most appropriate vegetation treatments based on the relative resilience and resistance of the ecosystem and the likely successional pathways. 

Vegetation treatments addressed include prescribed fire and mechanical 

treatments to decrease fuel loads, increase native perennial grasses and 

forbs, and reduce the risk of invasive annual grass dominance. The need for 

post-fire rehabilitation treatments to stabilize soils and reestablish vegetation communities is also addressed.

Although this field guide is intended to assist in evaluating areas being considered for vegetation management treatments, the concepts, components, 

and questions are generally applicable to areas burned by wildfire or otherwise 

disturbed.

Approach

A set of Key Questions related to Seven Primary Components (shown in 

fig. 1) for the treatment area are used to evaluate resilience to disturbance or 

treatment, resistance to invasive annual grasses, and potential successional 

pathways, and to determine the most appropriate management treatment.

Area of Application

This field guide was developed for the northern Great Basin and Columbia River 

Plateau (fig. 2), which encompasses 11 Major Land Resource Areas (MLRAs) 

(table 1). MLRAs are geographically associated land resource units, usually encompassing several to many million acres. They are characterized by particular 
USDA Forest Service RMRS-GTR-322. 2014 3

Figure 1. A conceptual model of the primary components that drive plant successional trajectories following 

prescribed fire or mechanical treatment. These components are the basis for a series of key questions to 

be addressed when evaluating site resilience to treatment applications and resistance to invasive annual 

grasses and predicting post-treatment responses.
4 USDA Forest Service RMRS-GTR-322. 2014

patterns of soils, geology, climate, water resources, and land use. The MLRA in 

which the proposed treatment area is located provides important information 

for site evaluation and includes:

1. The elevation, topographic position, and indicator species that are used to 

identify soil temperature/moisture regimes, and that are closely linked to 

resilience to disturbance atnd management treatments and resistance to 

invasives (see fig. 3 and Appendix 1).

2. The relevant ecological site descriptions (ESDs, see Appendix 9 for definition). ESDs are usually unique to each MLRA, but similar ESDs may occur 

across MLRAs.

3. The potential vegetation (see Appendix 9). Species composition may 

change across MRLAs, but the functional roles of plant groups (for example, deep-rooted and shallow-rooted perennial grasses, perennial forbs, 

and shrubs) are usually similar across MLRAs within the Great Basin and 

Columbia River Plateau regions.

When predicting vegetation response to vegetation treatments across different 

areas, comparing similarities among specific ecological site characteristics (including soil moisture/temperature regimes and composition of the plant groups, 

such as deep-rooted perennial grasses) is usually more important than differences 

in geographic locations within or across MLRA’s.
USDA Forest Service RMRS-GTR-322. 2014 5

Figure 2. Major Land Resource Areas (MLRAs) located in the Great Basin and Columbia River 

Plateau Region: Columbia Plateau (8); Blue Mountain Foothills (10); Snake River Plain (11); Klamath 

Valleys (21); Malheur High Plateau (23); Humboldt Area (24); Owyhee High Plateau (25); Carson 

Basin and Mountains (26); Fallon-Lovelock (27); Great Salt Lake (28A); and Central Nevada Basin 

and Range (28B) (derived from USDA Natural Resources Conservation Service 2011 by Eugénie 

MontBlanc, University of Nevada, Reno, NV).
6 USDA Forest Service RMRS-GTR-322. 2014

Figure 3. A conceptual model that illustrates the factors that influence resilience to treatment and resistance to invasive 

species. Ecological site characteristics or environmental factors are the primary factors that influence soil temperature/

moisture regimes and potential vegetation. The regimes are identified in soil maps as mesic (warm), frigid (cool), cryic (cold), 

aridic (dry), and xeric (moist). Potential vegetation + disturbance history + time since disturbance or treatment = current 

vegetation. If all of the ecological site characteristics are favorable for treatment and the site attributes and processes are all 

functioning within the natural range of variability then levels of resilience to treatment application and resistance to invasive 

species are near potential for that site. However, if the site is not at potential because one or more components are below 

potential or missing, for example, perennial grasses are severely depleted or invasive annual grasses are abundant, resilience 

to disturbance and/or resistance to invasive annual grasses will be lower than potential (adapted from Chambers and others 

2014).
USDA Forest Service RMRS-GTR-322. 2014

7

Table 1. Major Land Resource Area (MLRA) names and identification numbers (see fig. 2 for map) included in this field guide. The size of land area, states listed in descending order of proportion of area it covers, most common elevation range (extreme), geology, common soil orders, range of average annual precipitation (extremes), and range in temperatures are described for each MLRA. The field guide covers only the sagebrush, salt-desert, and piñon pine and juniper communities within these MLRAs. MLRAs 8, 10, and 11 are located in the Northwestern Wheat and Range Region. The remaining MLRAs are located in the Western Range and Irrigated Region. Descriptions are derived from USDA Natural Resources Conservation Service 2011.

MLRA (id #) Area (mi2) States Elevation ft Geology Soils PPT inches Temp °F

Columbia Plateau

(8) 18,505 WA OR ID 1,300-3,600 basalt Mollisols 10-16 (6-36) 48-54

Blue Mt Foothills

(10) 17,515 OR ID 1,300-6,600 basalt alluvium sedimentary Mollisols, Aridisols 8-16 (41) 36-53

Snake River Plain 

(11) 16,475 ID OR 2,100-5,000 Idaho Batholith, basalts Aridisols 7-12 (20) 41-55

Klamath Valleys 

(21) 11,495 CA OR 2,600-4,600 (>7,000) basalt rhyolite andesite Mollisols 12-30 (9; 30-58) 39-52

Malheur High 

Plateau

(23)

22,896 OR NV CA 3,900-6,900 (>9,000) basalt & andesite Aridisols, Mollisols 6 – 12 (>50) 39-52

Humboldt Area 

(24) 12,680 NV OR 3950-5,900 (>8850) alluvium (some andesite & basalt) Entisols, Inceptisols, Mollisols 6-12 (40) 38-53

Owyhee High 

Plateau 

(25)

28,930 NV ID OR UT 3,000-7,550 (>9,800) andesite basalt rhyolite Aridisols, Mollisols 7-16 (>50) 35-53

Carson Basin & Mts 

(26) 6,520 NV CA 3,900-6,550 (13,100) granitic andesite basalt Aridisols, Mollisols 5-36 37-54

Fallon-Lovelock

(27) 12,565 NV CA 3,300-5,900 (<7,800) alluvium andesite basalt Aridisols, Entisols 5-10 (19) 43-54

Central NV Basin & 

Range 

(28B)

23,555 NV

3,950-6,560 basin

6,560-11,150 mts

playa lakebed 

deposits, 

Aridisols, Entisols, 

Mollisols 5-12 (49) 39-53

Great Salt Lake

(28A) 36,775 UT NV ID

4,900-6,550 basin

6,550-11,900 mts 

carbonate (north) 

andesite basalt

Aridisols, Entisols, 

Mollisols

4-12 (basins)

8-36 

(mountains)

34-52
8 USDA Forest Service RMRS-GTR-322. 2014

Supporting Information

The framework for the field guide is based on a recent synthesis of the state-ofour-knowledge titled, A Review of Fire Effects on Vegetation and Soils in the Great 

Basin Region: Response and Ecological Site Characteristics, RMRS-GTR-308, by 

Miller and others 2013. Additional information required for evaluating areas 

being considered for treatment includes soil surveys, ecological site descriptions, and potential and current vegetation (see http://websoilsurvey.sc.egov.

usda.gov/App/HomePage.htm; http://www.nrcs.usda.gov/wps/portal/nrcs/

main/national/technical/ecoscience/desc/).

This field guide is not a guide for restoration/rehabilitation strategies following 

vegetation treatments. However, the components and questions in the guide 

can be used to evaluate the suitability of an area for seeding based on ecological site characteristics and the need for seeding based on current vegetation. 

A companion field guide is being prepared that specifically addresses how to 

evaluate the resilience and resistance of an area immediately following a wildfire, the area’s suitability for seeding, and the need for seeding after wildfire. It 

is titled A Field Guide for Determining Post-Fire Recovery and the Need for PostFire Seeding in Sagebrush and Piñon-Juniper Ecosystems in the Great Basin. Once 

the suitability of a site and need for seeding have been determined, restoration/rehabilitation methods can be found in references such as Field Guide for 

Restoration of Sagebrush-Steppe: Ecosystems with Special Emphasis on Greater 

Sage-grouse Habitats, by Pyke and others, in process, and Restoring Western 

Ranges and Wildlands, by Monsen and others 2004.

Basic Questions to Address Prior to Implementing 

Vegetation Treatments

1. What is the resilience (recovery potential) of the ecological sites across the 

proposed treatment area?

2. How resistant are the ecological sites to invasive annual grasses on the proposed treatment area?

3. How will different types of treatments and their severity influence resilience, resistance to invasives, and successional pathway(s) for the proposed 

treatment area?

4. Based on answers to the above three questions, what are the most appropriate vegetation treatment(s) for the proposed treatment area?

To address these questions specific characteristics of the seven primary components should be considered.
USDA Forest Service RMRS-GTR-322. 2014 9

The Seven Primary Components

Ecological function and plant successional pathways are closely related to and 

dependent on (1) ecological site characteristics + (2) current vegetation (composition and structure) + (3) disturbance history + (4) treatment type, timing, severity, 

and frequency + (5) post-treatment weather + (6) post-treatment grazing + (7) 

monitoring and adaptive management

The key questions identify specific characteristics of the seven primary 

components that drive plant succession following treatment and influence 

longer-term outcomes (fig. 1).
10 USDA Forest Service RMRS-GTR-322. 2014

Key Questions Addressing 

Each of the Seven Primary 

Components

10 USDA Forest Service RMRS-GTR-322. 2014

1-Ecological Site Characteristics

Climate, topography, and soils affect water availability, temperature regimes, 

potential vegetation, and productivity, which in turn affect resilience to disturbance and treatments and resistance to invasives (fig. 3; Appendix 1). Due 

to underlying differences in characteristics of ecological sites, resilience to 

treatment and resistance to annual invasive species differs. Five generalized 

ecological types for big sagebrush in 

the Great Basin and Columbia River 

Plateau regions are presented in table 2. 

They represent groupings of ecological 

sites that are occupied by Wyoming or 

mountain big sagebrush, span a range 

of soil temperature/moisture regimes 

(warm-dry to cold-moist), and characterize a large portion of the Great Basin 

and Columbia River Plateau regions. To 

determine the relative resilience and resistance of specific or generalized ecological sites in the area prior to treatment, it is necessary to evaluate the soil 

temperature/moisture regimes, potential vegetation, and current vegetation.

In ecology, the term mesic

is often used to mean moist 

or medium water supply for 

plant growth. However, in soil 

terminology and used in soil family 

names, mesic refers to warm 

soils, which in the Great Basin 

are often occupied by Wyoming 

big sagebrush and have relatively 

low resistance to invasive annual 

grasses (see Appendix 3).
USDA Forest Service RMRS-GTR-322. 2014 11 Table 2. The five generalized ecological types for big sagebrush, their characteristics, and their resilience to wildfire and resistance to invasive annual grasses. Ecological Type Site Characteristics Resilience and resistance Warm and dry Wyoming Big Sagebrush Soil temperature/moisture regime: Mesic/aridic Precipitation (Ppt): 8-12-in Indicator shrubs: Artemisia tridentata ssp. wyomingensis Indicator grasses: Pseudoroegneria spicata, Achnatherum thurberianum on cooler/moister sites; A. hymenoides, A. comata, Elymus elymoides, Poa secunda on drier/warmer sites Resilience – Low. Effective precipitation limits site productivity. Decreases in site productivity, herbaceous perennial species, and ecological conditions further decrease resilience. Resistance – Low. High climate suitability to cheatgrass and other invasive annual grasses. Resistance generally decreases as soil temperature increases, but establishment and growth are highly dependent on precipitation and vary among years. Warm and moist Big sagebrush Piñon and Juniper Potential Soil temperature/moisture regime: Cool mesic to warm frigid/xeric Ppt:12-14-in Indicator shrubs: A. tridentata ssp. wyomingensis, A. tridentata ssp. vaseyana, Purshia tridentata Indicator grasses: Pseudoroegneria spicata Resilience – Moderate. Precipitation and productivity are moderately high. Decreases in site productivity, herbaceous perennial species, and ecological conditions can decrease resilience. Resistance – Moderately low. Climate suitability to invasive annual grasses is moderately low, but increases as soil temperatures increase. Cool and moist Mountain big sagebrush Soil temperature/moisture regime: Cool mesic to cool frigid/xeric Ppt: 12-14-in Indicator shrubs: Artemisia tridentata ssp. vaseyana, Purshia tridentata Indicator grasses: Festuca idahoensis, Poa fendleriana Resilience – Moderate. Precipitation and productivity are moderately high. Decreases in site productivity, herbaceous perennial species, and ecological conditions can decrease resilience. Resistance – Moderate. Climate suitability to invasive annual grasses is moderate, but increases as soil temperatures increase. Cool/cold and moist Mountain big sagebrush Piñon and Juniper Potential Soil temperature/moisture regime: Cool frigid/xeric Ppt: 12-14-in + Indicator shrubs: A. tridentata ssp. vaseyana, Amelanchier ssp., Symphoricarpos ssp. Indicator grasses: Festuca idahoensis, Koeleria macrantha, Melica bulbosa Resilience – Moderately high. Precipitation and productivity are generally high. Decreases in site productivity, herbaceous perennial species, and ecological conditions can decrease resilience. Resistance – Moderately high. Low climate suitability to invasive annual grasses. Cold and moist Mountain big sagebrush Soil temperature/moisture regime: Cryic/xeric Ppt: 14-in + Indicator shrubs: A. tridentata ssp. vaseyana, Amelanchier ssp., Symphoricarpos ssp. Indicator grasses: Festuca idahoensis, Koeleria macrantha, Melica bulbosa Resilience – Moderately high. Precipitation and productivity are generally high. Short growing seasons can decrease resilience on coldest sites. Resistance – High. Low climate suitability to invasive annual grasses. 
12 USDA Forest Service RMRS-GTR-322. 2014

Soil Temperature Regime

1. Are the soils warm (mesic), cool (frigid), or cold (cryic) (fig. 4 A and B)?

a. This information can be attained from soil maps, soil family names, and/or 

elevation based on criteria used for soils mapping in the appropriate MLRA 

(Appendices 2 and 3). Plant species composition also can be an indicator 

(see Potential Vegetation below).

2. Do elevation and aspect place the ecological site on the upper or lower 

end of the soil temperature regime (for example, warm-mesic versus coolmesic) (fig. 4)?

Figure 4. A conceptual model of (A) 

resilience to treatment and (B) resistance 

to invasive annual grasses for Wyoming big 

sage (ARTRw), mountain big sagebrush 

(ARTRv), and mountain big sagebrushsnowberry (ARTRv-SYOR) along an elevation/

productivity gradient in which soil temperature/

moisture regimes grade from warm-dry 

(mesic-aridic) to cold-moist (cryic-xeric). Soil 

moisture availability along these gradients is 

modified by soil characteristics. The mountain 

big sagebrush-snowberry (ARTRv-SYOR) 

type is similar to mountain shrub in Nevada 

and Utah and often includes mountain 

big sagebrush, snowberry, serviceberry, 

bitterbrush, and curl-leaf mountain mahogany. 

Resilience and resistance are affected by 

topography; the dashed dark blue and red 

lines in the resilience graph illustrate the 

effects of aspect. The potential resilience and 

resistance of a site is determined by ecological 

site characteristics; resilience and resistance 

can be lowered if certain site components 

such as perennial grass abundance are 

depleted as a result of disturbance history 

or climate change. In the resistance graph, 

the solid green line represents potential 

resistance to annual invasives in the 

reference state and the red line indicates 

decline in resistance as a result of a phase 

being at-risk. The relationship between soil 

temperature/moisture regimes and elevation 

changes across MLRAs (see Appendix 2). 

Soil temperature/moisture regimes are not 

separated by distinct boundaries but represent 

a gradient (shown by the overlapping arrows). 

Changes in soil temperature and moisture can 

be gradual (a gradual increase in elevation) 

or abrupt (a shift from a south to an opposing north aspect). The shift from one sagebrush 

subspecies to another does not have a definite lower or upper elevation limit, but will vary 

with other site attributes including location (MLRA), soils, aspect, and microtopography. 

For example, an overlap of cool (frigid) mountain big sage (ARTRv) into warm (mesic) 

Wyoming big sagebrush (ARTRw) can occur, and is often influenced by soil moisture 

availability. As environmental gradients move to the right, resilience and resistance 

increase. Productivity and thus fuel loads also increase resulting in a greater potential for 

more frequent fires. (from Chambers and others, 2013).
USDA Forest Service RMRS-GTR-322. 2014 13

In reality soil moisture/temperature regimes are gradients. Thus, it helps to know 

if the ecological site is warm, mid, or cool relative to a specific soil temperature 

regime (fig. 4, Appendix 2). This usually can be determined by the elevation and 

aspect of the ecological site. Indicator plant species also can be helpful. North 

and south aspects with >15% slope are usually adjusted by 500 ft. For example, 

in MLRA23 the elevation boundary for mesic and frigid soils is 4000 ft, but it is 

adjusted down to 3500 ft on north aspects and up to 4500 ft on south aspects.

Soil Moisture Regime

3. Does the ecological site have a dry aridic (<10-in ppt), aridic (10-12-in ppt), 

or xeric (>12-in ppt) moisture regime? (See table 3 and figs. 5 and 6 for indicator species.)

4. Is the soil depth very shallow (<10-in), shallow (10-20-in), moderately deep 

(20-36-in), or deep (>36-in)?

a. Soil depth influences the water storage capacity of the ecological site. 

Some very shallow soils (<10-in) may be mapped as aridic due to limited 

water storage capacity even though annual precipitation is >12-in (xeric).

b. A general estimate of soil depth can be determined by the species or 

subspecies of sagebrush and their height (fig. 5 and table 3). However, 

digging small soil pits is the best technique to determine soil depth in a 

proposed treatment area.

5. Is the soil texture clay, sandy, silt, loam, clay-loam, sandy-loam, silt-loam 

(see Appendix 3)?

a. Texture is an important soil characteristic because it influences soil water 

capture and storage. Soils with loamy textures have the greatest capacity 

for both capturing and storing water for plant use.
14 USDA Forest Service RMRS-GTR-322. 2014

Table 3. Site characteristics that often occur with different sagebrush and associated shrub species. Lower elevation limits vary 

widely across Major Land Resource Areas. For example, the elevation where the transition of Wyoming to mountain big sagebrush occurs (modified by aspect) is commonly around 4500 ft in the High Malheur Plateau (MLRA 23) and 6500-7500 ft in the 

Central Nevada Basin and Range (MLRA 28B) (from USDA-NRCS Plant Guide; Mahalovich and McArthur 2004). Precipitation 

(PPT) values in parentheses indicate extremes.

Soil

Species PPT

(in)

Elevation

(ft)

Depth

(in)

Moisture 

regime

Temperature 

regime Soil properties

Wyoming big 

sagebrush 8-12(6) 2600-7200 10-30 Aridic Mesic Loamy soils with high clay content

Basin big sagebrush 8-16 600-2100 >36 Aridic-xeric Mesic Loamy to sandy

Mountain big 

sagebrush >12 2600-10000 18-36 Xeric Frigid-cryic Loamy to gravely to clay loam

Xeric big sagebrush 12-16 2600-4900

(7200) >16 Xeric Mesic (frigid) Basalt or granitic

Low sagebrush 2300-12000 <20 Aridic-xeric Frigid-cryic 

(mesic)

Rocky, shallow, 

clay soils

Black sagebrush <12 2000-10000 <20 Aridic xeric Mesic-frigid Shallow, stony, 

calcareous

Snowbank big 

sagebrush >12 6800-10000 >20 Xeric Cryic Snow accumulation areas

Other Shrubs

Snowberry >14 4800-10000 >20 Xeric Cool frigid to 

cryic

Sandy to clay 

loams

Serviceberry >14 5000-8500 >20 Xeric Cool frigid-cryic Loam

Shadscale 4-8 4000-7000 >20 Dry-aridic Mesic-frigid Aridisols (uplands)

Spiny hopsage <8 2000-5500 >20 Dry-aridic Mesic Aridisols

Mormon tea <10 (15) 3000-7500 >20 Dry-aridic Mesic Sandy, gravely, 

rocky aridisols
USDA Forest Service RMRS-GTR-322. 2014 15

Figure 5. Major sagebrush taxa in the Great Basin and Columbia River Plateau positioned along gradients of soil 

temperature and soil moisture (adapted from Robertson and others 1966; McArthur 1983; West 1983; West and 

Young 2000; Rosentreter 2005; Schultz 2009, 2013). Key soil characteristics associated with each species are shown 

under the species name. Relative abundance of the sagebrush species and subspecies in the Great Basin and 

Columbia River Plateau is color coded: tan = scarce, orange = common, and green = dominant. 
16 USDA Forest Service RMRS-GTR-322. 2014

What is in a soil family name?

A soil family name includes important information on related soil characteristics 

that influence ecological site resilience to treatment, resistance to invasives, and 

potential vegetation. This includes information related to relative organic matter 

content (Aridisols or Mollisols), soil depth (for example, mention of a restrictive 

layer), texture, and the soil temperature/moisture regime (mesic, frigid, or cryic, 

and aridic or xeric) (see Appendix 3 for examples).

Potential Vegetation

The potential vegetation of an ecological site, as described in an ESD, is a 

function of ecological site characteristics (climate, topography, and soils), 

attributes and processes (soil temperature/moisture regime, soil processes, 

and vegetation dynamics), and disturbance regime (fig. 3). Due to strong 

topographic gradients, which influence moisture and temperature and thus 

potential vegetation in the Great Basin and Columbia River Plateau, dominant 

plant species such as sagebrush are good indicators of soil temperature/moisture regimes (table 3).

1. What is (are) the dominant shrub species or subspecies of sagebrush (fig. 5, 

table 3; see Shultz 2013)?

a. Wyoming big sagebrush is most commonly found on moderately deep, 

mesic/dry-aridic to aridic (warm/dry) soils but can occur on warm-frigid 

soils, especially if the moisture regime is aridic (fig. 4).

b. Mountain big sagebrush is most commonly found on moderately deep 

frigid/xeric soils but also occurs on warm-cryic soils.

Figure 6. The general distribution of common, deep-rooted grasses and cheatgrass across a soil moisture/temperature 

gradient in the Great Basin and Columbia River Plateau.
USDA Forest Service RMRS-GTR-322. 2014 17

2. Some shrub species associated with sagebrush (usually present or co-dominant but not dominant) are also indictors of soil temperature/moisture 

regimes. For example, snowberry and serviceberry are common on coolfrigid and cryic soils with >14-in precipitation. In upland non-saline soils, 

shadscale and spiny hopsage often occur on mesic/dry-aridic soils typically 

with <8-in precipitation (table 3).

3. What are the perennial grass species that potentially dominate a site?

a. The perennial grass species that are potentially common or dominant in 

the reference state (see Appendix 9 for definition) for the ecological site 

are general indicators of moisture availability, temperature (fig. 6), and 

soil depth and texture.

b. If Sandberg’s bluegrass is the dominant grass it can be an indicator of 

very shallow soils (<10-in) or if on shallow to moderately deep soils (>10-

in) of inappropriate grazing resulting in the loss of larger bunchgrasses. 

Also, a high abundance of bottlebrush squirreltail is often an indicator of 

high severity and/or frequent disturbance. However, these two species 

increase resilience and resistance to invasive annual grasses where soils 

are shallow, on relatively warm and dry sites, and where perennial, native 

herbaceous species have been depleted.

4. Is the reference state a shrubland or piñon pine and/or juniper woodland?

a. Are there old-growth juniper and/or piñon pine on the proposed 

treatment area?

b. Are there remnants of large tree stumps or logs, which show evidence of 

fire that indicate the area was previously occupied by large trees?

Note that some ecological site descriptions that include piñon pine or juniper in 

the reference state do not differentiate old growth and post-settlement trees. 

However, in newer ESDs with state and transition models, it is easier to make 

this distinction. To determine the type of woodland, see the “Piñon Pine and/or 

Juniper Encroachment” section below.

2-Current Vegetation

Current vegetation plays a major role in the recovery of an ecological site 

following treatment. The persistence and abundance of perennial vegetation immediately following treatment is one of the primary drivers of both 

short- and long-term successional pathways. Post-treatment persistence and 

abundance of perennial vegetation are a function of pre-treatment plant community composition and structure, treatment type, timing, and severity, and 

species’ tolerance to the treatment.
18 USDA Forest Service RMRS-GTR-322. 2014

Perennial Grasses and Forbs

1. What is the composition and structure (cover and/or density) of perennial 

native grasses and forbs?

a. Are they scarce to absent?

b. Are they severely depleted? (perennial grasses are <2/10ft2 for xeric and 

<3/10ft2 for aridic; invasives dominant or, if invasives are not dominant, 

woody species [shrubs or trees] are near maximum cover)

c. Depleted or codominant with invasive annual grasses? (Abundance of 

perennial grasses and forbs are near or equal to abundance of invasives 

[annual exotic abundance is highly variable with moisture]. If invasives 

have low abundance [<5% cover], perennial grass densities >2/10ft2 for 

xeric and >3/10ft2 for aridic but cover typically does not exceed 10%.)

d. Dominant (near reference state).

Invasive Annual Grass Potential

1. What is the potential for invasive annual grasses and other invaders to increase based on ecological site characteristics (figs. 3 and 4), seed source 

(on or off site), and the type, timing, and severity of treatment?

a. Do the perennial native herbaceous species have sufficient density and/

or cover to ensure ecological site recovery? The density and/or cover 

of native perennial herbaceous species necessary for post-treatment 

recovery will vary with ecological site characteristics, severity and timing 

of the treatment, and post-treatment weather (fig. 1).

b. Resistance to invasive annual grasses and other annual invasives 

decreases as a function of ecological site characteristics that include 

warmer soil temperatures and drier moisture regimes (fig. 4B, table 2). 

As resistance decreases, the abundance of residual vegetation required 

for recovery increases. Data are limited, but one example showed that 

following the removal of a closed western juniper stand on the low 

elevation end of a cool soil temperature regime (warm-frigid) (southwest 

slope at 5000 ft in the Malheur High Plateau MLRA), 2-3 deep-rooted 

perennial grasses per 10 ft2 was sufficient for bunchgrasses to recover 

(Bates and others 2007). A second example showed that following either 

prescribed fire or mowing of sagebrush on Wyoming big sagebrush sites 

with mesic soil temperature regimes in six MLRAs (Columbia Basin, 

Columbia Plateau, Malheur High Plateau, Snake River Plains and Great 

Salt Lake Area), a 20% cover of perennial native herbaceous species 

(both grasses and forbs) was required to prevent significant increases 

in cheatgrass after treatment (Chambers and others, in press). These 

examples indicate that higher cover or densities of perennial herbaceous 
USDA Forest Service RMRS-GTR-322. 2014 19

species may be required for post-treatment recovery on warmer and 

drier sites with lower resistance to annual invasive species.

c. What are the current composition, distribution, and abundance of 

invasive annual grasses and other invaders? Note that the densities, 

cover, and biomass of annual species are highly variable among years, 

and values obtained in a dry spring often will not reflect those obtained 

in an average or wet spring.

On a mesic/aridic ecological site, annual grass cover in one long-term study varied 

from trace in dry years to 25% in wet years.

d. What is the potential for invasive annual grasses and other invaders 

to increase on the treatment site based on seed source (on or off site), 

current disturbances, and future livestock grazing?

Piñon Pine and/or Juniper Encroachment?

1. If piñon pine and/or juniper are present on the proposed treatment area, 

what type of woodland is it?

a. Is the area comprised largely of: (a) old growth (>10% canopy cover); 

(b) a low density of old trees scattered across the area (<10% cover) and 

infilled with post-settlement trees; or (c) post-settlement trees where 

old growth is either absent (including old stumps and logs) or isolated 

to specific topographic positions (for example, ridges) and/or soils? To 

distinguish historic woodlands from encroachment areas the following 

questions can be addressed:

i. What is the age structure of live trees (based on morphology, see 

Appendix 4a, b)?

ii. Are there large stumps, burned snags, or logs indicating mortality 

of large trees from a past fire? If yes, would the projected tree cover 

(based on density of stumps, snags, and logs) have been open savanna-like (<10%) or woodland (>10%)?

iii. What is the distribution of the old trees across the treatment area? 

Do they occur in small patches on specific kinds of soils or landscape 

positions, or do they occur across the majority of the area?

Note that fire-return intervals of less than 40-50 years, especially on cooler, moister ecological sites, are usually required to limit the transition 

from shrubland to woodland where there is a piñon pine and/or juniper 

seed source nearby (fig. 7).
20 USDA Forest Service RMRS-GTR-322. 2014

b. If the treatment area is predominately old growth or contains patches of 

old growth, how does this influence management goals and treatment 

application?

c. If the trees are predominately young (<150 yrs) and have encroached or 

infilled into a location of concern that historically was predominately a 

shrubland community, the following questions should be addressed:

i. Based on the density, canopy cover, and age structure, what is the 

woodland phase (see Appendix 9 for definitions)?

ii. How will the density and size of trees influence fire behavior and 

severity (see fire severity below)?

iii. How will fuel structure influence treatment selection and the ability 

to apply fire?

iv. To what degree is the tree canopy influencing the understory 

composition and thus recovery potential?

v. Is the grass and forb cover in the large interspaces between the trees 

severely depleted (<5% foliar cover) or moderately depleted (5-10% 

foliar cover)?

vi. Is there high shrub mortality based on standing shrub skeletons or 

persistent litter?

vii. Are there obvious signs of rill and sheet erosion that exceed the 

levels expected on the site (as described in the reference sheet for the 

appropriate ESD) (fig. 8)?

Figure 7. A conceptual model illustrating 

the range of potential historic mean firereturn intervals (MFRI, years between fires) 

in the Great Basin and Columbia River 

Plateau. MFRI increases along a moisture 

and temperature gradient from cool-moist 

to warm-dry as a result of decreasing fuel 

abundance and continuity. The combination of 

temperature, water availability for plant growth, 

and fire regime influences the potential natural 

vegetation that can persist as illustrated in 

figure 7. Sagebrush ecosystems gray; historic 

woodland is brow, and grassland is green. 

Persistent vegetation that occupies the gray 

area is likely a sagebrush herbaceous mix with 

relative abundance of each dependent on time 

since fire and ecological site characteristics 

(from Miller and others 2011). Packrat-midden 

and pollen data indicate that the proportion of 

each plant community type across the Great 

Basin has been dynamic during the Holocene 

(last 10,500 years) as a result of shifting 

climate and fire regimes.
USDA Forest Service RMRS-GTR-322. 2014 21

Figure 8. (A) Changes in sagebrush shrublands with advancing woodland encroachment; (B) the associated degradationinduced shift in the dominate erosion processes; and (C) a representative increase in erosion magnitude associated with 

changes in site/ground surface conditions. Erosion from stable sagebrush communities occurs primarily by rainsplash 

and sheetflow and is typically low. Erosion increases exponentially with site and ground surface degradation where bare 

soil increases beyond 50-60%. High rates of erosion typically occur where sagebrush communities transition to Phase 

II-III woodlands. The exponential increase in soil loss (C, red line) with site/ground surface degradation illustrates the 

effect of concentrated flow. Concentrated flow is the dominant erosion process at the transition from Phase II-III woodland 

encroachment and signals a transition from a stable to a degrading landscape. Concentrated flow has higher velocity than 

sheetflow and thereby exhibits greater sediment detachment and transport capacity than the combined effects of rainsplash 

and sheetflow (from Miller and others 2013).
22 USDA Forest Service RMRS-GTR-322. 2014

viii. If the woodland is in phase I or II (see Appendix 9 for definition), 

what is the expected rate of stand closure based on ecological site 

productivity (fig. 9)?

ix. What is the distance to the nearest piñon pine or juniper seed source? 

And, if the treatment area is large, what areas are most vulnerable to 

seed dispersal?

The majority of bird and small mammal disseminated juniper seed is dispersed 

within 300 ft of the seed source. However, birds can disseminate seed up to 3 miles 

or more.

2. What is the fire tolerance of plant species on the site?

a. How fire-tolerant are native and invasive species on the ecological site 

and how will this potentially influence post-treatment composition?

b. What is the fire tolerance of species of concern (for example, sagebrush 

or threatened and endangered species) and what is their potential for 

recovery after treatment implementation?

i. Is the area sage-grouse nesting, brood rearing, or winter habitat?

ii. What is the plant composition and structure of areas adjacent to the 

treatment area and how large is the treatment area?

Fire tolerance of most herbaceous vegetation often can be determined from visible morphological traits (table 4). When applying prescribed fire, it is important to 

distinguish shrubs that are sprouters and non-sprouters (table 5).

Figure 9. The hypothesized 

amount of time required 

from initial western juniper 

establishment (early Phase I) 

to a minimum stocking level 

adequate for Phase III, and 

the estimated maximum 

potential for tree density and 

cover for stands developing 

on varying elevations and 

aspects (from Johnson and 

Miller 2006). Projected rates 

of closure are similar for 

piñon pine and Utah juniper 

(Tausch and others 2009). 
USDA Forest Service RMRS-GTR-322. 2014 23

3-Disturbance History

1. How much has disturbance history altered the proposed treatment area?

2. What types of past disturbances have potentially impacted vegetation 

structure and composition?

3. How are current disturbances or management affecting existing vegetation 

structure and composition?

4-Treatment Type and Severity

As resiliency to disturbance(s) and resistance to invasive annual grasses and 

other invasives decreases, treatment severity becomes of greater concern and 

selection of the appropriate treatment method and timing becomes increasingly important (see the section below on “Selecting the Most Appropriate 

Treatment Method”).

Table 4. Examples of some common perennial forbs in the Great Basin and Columbia River Plateau Regions and their tolerance 

to fire as related to their growth form.

Tolerant

(damage none to slight)

Intolerant

(damage—moderate to severe)

Buds below ground

common yarrow (Achillea millefolium)

mountain dandelion (Agoseris spp.) 

onion (Allium sp.)

aster sp. (Aster sp.)

milkvetch sp. (Astragalus sp.)

arrowleaf balsamroot (Balsamorhiza spp.)

mariposa lilly (Calochortus spp.)

hawksbeard (Crepis spp.)

fleabane (Erigeron spp.)

sticky purple geranium (Geranium viscosissimum)

old man’s whiskers (Geum triflorum)

biscuitroot (Lomatium spp.) 

lupine sp. (Lupinus spp.)

bluebells sp. (Mertensia spp.)

woolly groundsel (Pakera cana)

penstemon spp. (Penstemon spp.)

longleaf phlox (Phlox longifolia)

lambstongue ragwort (Senecio integerrimus)

largehead clover (Trifolium macrocarpum)

death camus spp. (Zigadenus spp.)

mules ear (Wyethia amplexicaulis)

Buds above ground

pussytoes (Antennaria spp.)

sandwort (Arenaria spp.)

matted buckwheat. (Eriogonum caespitosum)

Douglas buckwheat (Eriogonum douglasii)

parsnip buckwheat (Eriogonum heracleoides)

slender buckwheat (Eriogonum microthecum)

rock buckwheat (Eriogonum sphaerocephalum)

sulfur-flower buckwheat (Eriogonum umbellatum)

spiny phlox (Phlox hoodii)

Derived from Blaisdell 1953; Pechanec and others 1954; Mueggler and Blaisdell 1958; Lyon and Stickney 1976; Klebenow 

and Beall 1977; Wright and others 1979; Volland and Dell 1981; Bradley and others 1992; Pyle and Crawford 1996; Riegel and 

others 2006; USDA-Forest Service 2013.
24 USDA Forest Service RMRS-GTR-322. 2014

Prescribed Fire

Pre-fire fuels assessment

1. How will the abundance and structure of current vegetation influence fire 

severity (see fig. 10)?

a. Are the surface fuels adequate to carry a fire across a shrubland 

community or woodland?

b. If wooded, in what woodland phase (I, II, or III) is the stand? In addition 

to increasing fuel loads, later woodland phases, Phase II and especially 

Phase III, require more extreme weather conditions (lower humidity, 

higher temperatures and wind speeds) to carry fire due to lack of 

horizontal fuel continuity resulting from limited surface fuels.

c If wooded, are the ladder fuels (primarily shrubs) sufficient to carry the 

fire into the tree canopy?

Table 5. Potential response of common shrubs to fire in the Great Basin and Columbia River Plateau Regions (s).

Tolerant Moderately Tolerant Intolerant

silver sagebrush (Artemisia cana)(s)

snowfield sagebrush (Artemisia spiciformis) (s)

aspen (Populus tremuloides)(s)

green rabbitbrush (Chrysothamnus 

viscidiflorus)(s)

wax current (Ribes cereum)(s)

desert gooseberry (Ribes velutinum)(s)

Woods’ rose (Rosa woodsii)(s)

mountain snowberry (Symphoricarpos 

oreophilus)(s)

horsebrush sp (Tetradymia sp.)(s)

serviceberry (Amelanchier alnifolia)(s)

Stansbury cliffrose (Purshia stansburiana)(s)

desert bitterbrush (Purshia tridentata var. 

glandulosa)(s)

Nevada Mormon tea (Ephedera nevadensis)(s)

greasewood (Sarcobatus velutinus)(s)

Torrey’s saltbush (Atriplex torreyii)(s)

Gardner’s saltbush (Atriplex gardnerii)(s)

Sagebrush Steppe

rubber rabbitbrush 

(Ericameria nauseosus)(s)

three-tip sagebrush 

(Artemisia tripartita)(ws)

Desert Shrub

low sagebrush (Artemisia cana)(ns)

black sagebrush (Artemisia nova)(ns)

big sagebrush (Artemisia tridentata)(ns)

curl-leaf mountain mahogany (Cercocarpus 

ledifolius)(ws)

antelope bitterbrush (Purshia tridentata var. 

tridentata)(ws)

Mexican cliffrose (Purshia mexicana)(ws)

broom snakeweed (Guiterrezia sarothrae)(ws)

spiny hopsage (Grayia spinosa)(ws)

bud sagebrush (Picrothamnus desertorum)(ns)

shadscale (Atriplex confertifolia)(ns)

fourwing saltbush (Atriplex canescens)(ws) 

winterfat (Krascheninnikovia lanata)(ws)

S = sprouter; ws = weak sprouter; ns = non-sprouter. Derived from Blaisdell 1953; Mueggler and Blaisdell 1958; Nord 1965; 

Wright 1972; Wright and others 1979; West 1994.
USDA Forest Service RMRS-GTR-322. 2014 25

d. If wooded, are the fuels from the trees (tree sizes, distances between 

canopies, and canopy density phases) so great as to result in a high 

severity fire?

e. What type of weather conditions are necessary to carry a fire and what 

kind of fire will likely occur—low, moderate, or high severity?

f. How will site characteristics such as aspect and slope effect fire severity?

g. How do fuels influence the season (early, mid, or late summer or fall) of 

burning and when is it most appropriate (see Miller and others 2013 for 

effects of season of burning)?

Assessing prescribed fire severity

2. Was the severity of the prescribed fire low, medium, high, or mixed across 

the treatment area?

a. What percentage of aboveground organic matter was consumed 

including trees, shrubs, herbs, and litter (see Appendix 5)?

b. What is the size and distribution of unburned, low to moderately burned, 

and high severity burned patches across the treatment area?

Figure 10. Fire behavior, including, intensity, duration, rate of spread, etc. are determined by three 

components: topography, climate and weather, and fuels. The specific traits of each of these components 

influence fire behavior and are closely related to fire severity.
26 USDA Forest Service RMRS-GTR-322. 2014

Mechanical Treatment

Severity

Surface disturbance by mechanical treatments varies with the method used 

and season, and can range from minimal to moderate (for example, cutting 

and falling trees, cabling sagebrush, mulching trees with a brush hog) to severe (for example, chaining piñon pine and/or juniper, bulldozing, plowing). 

When evaluating mechanical disturbance, one should consider the proportion of area impacted, and the effects of the treatment on soil/site stability 

and hydrologic function as described in “Interpreting Indicators of Rangeland 

Health.” Mechanical treatments that affect soil stability and hydrologic function are degree of soil movement (both depth and area), compaction, and the 

level of mortality of native species that results in a reduction in plant cover. 

Compaction can reduce infiltration rates (water capture) and seedling establishment. Soil movement that exposes bare soil or perennial plant roots can 

cause plant mortality and provides ideal seedbeds for invasive species.

5-Pre- and Post-Treatment Weather

Pre-treatment weather effects can be hard to quantify and post-treatment 

weather is unpredictable. However, weather conditions prior to a treatment 

can influence the abundance and continuity of fine fuel loads, percent dead 

fuels, and seed banks. Post-fire weather conditions can influence seedling establishment, recovery of plants that survive the treatment (both native and 

invasive species), and future seed crops. Consequently, weather can influence 

the type of post-treatment management actions including length of deferment from grazing or closure of treatment areas to off-road vehicles.

1. How has the weather 1-2 years prior to treatment affected the abundance and 

continuity of fine fuel loads?

2. How have potential seed banks (native and invasive species) been influenced 

by pre-treatment weather?

3. How will post-treatment weather influence successional pathways and will 

additional actions or multiple interventions potentially be needed (for example, invasive species control, seeding of native species, or transplanting 

sagebrush)?

a. Seed banks of perennial native species are often low, and seedling 

establishment usually only occurs during wet springs, especially on warmdry ecological sites.

c. Favorable weather conditions can increase establishment, productivity, 

and seed-crops of both desirable and undesirable plant species.
USDA Forest Service RMRS-GTR-322. 2014 27

d. Recovery in the first 1-2 years is typically dependent on persistent perennial 

vegetation that survived the treatment.

4. What is the potential for wind or water erosion in the first 1-2 years post 

treatment?

6-Post-Treatment Management

1. Assuming proper livestock grazing management, how long should the treatment area be deferred from grazing? This deferment period may vary by 

ecological site and if so, the ecological site that is most sensitive to grazing 

impacts should dictate the deferment period. In addition, pre-treatment plant 

composition and structure, and treatment severity and timing, can influence 

length of the deferment period.

a. Deferring grazing during the active growth period for the first two years is 

probably adequate only for ecological sites where:

• Treatment severity will be low to moderate;

• Resilience and resistance to invasives is high;

• Pre-treatment herbaceous vegetation is dominated by natives and 

invasive annual grasses are only a minor component; and

• Post-treatment monitoring indicates adequate recovery of shrubs, 

perennial grasses, and forbs.

b. Deferring grazing during the active growth period for the first two years is 

probably inadequate where any of the following apply:

• Treatment severity will likely be high;

• Resilience to treatment and resistance to invasives are moderate to low;

• Invasive annual grasses are co-dominant or dominant; and

• Post-treatment monitoring indicates low or slow recovery of perennial 

grasses and forbs.

The amount of time for post-treatment grazing deferment necessary for recovery 

is largely determined by: treatment severity + ecological site characteristics + pretreatment plant composition and structure + post-treatment weather.

2. What is the post-treatment level of control of grazing in terms of duration, 

stocking rates, distribution, and season of use?

3. What are the potential impacts of recreational use, wild horses and burros, and wildlife (for example, elk use in treated areas with increased grass 

abundance)?

The lack of adequate deferment or proper long-term grazing management can 

have a dramatic effect on the resilience and resistance of the treatment area 

(fig. 11)
28 USDA Forest Service RMRS-GTR-322. 2014

Figure 11. Seven year post-fire response comparison for a cool mesic/aridic-xeric Wyoming big 

sagebrush/Thurber’s needlegrass community in Nevada. Elevation is 7500-7800 ft and the area 

was grazed prior to treatment. The fence was installed after the fire. (A) In the absence of grazing 

perennial grasses have recovered and non-native invasive abundance is low. (B) Inappropriate 

grazing resulted in loss and/or limited recovery of deep-rooted perennial grasses and the 

dominance of non-native invasives.

B

A
USDA Forest Service RMRS-GTR-322. 2014 29

7-Monitoring and Adaptive Management

A monitoring plan should be in place before the treatment is implemented.

1. Do the monitoring protocols measure the project objectives?

2. Are the monitoring methods consistent with those being used elsewhere?

3. Is a plan in place for data entry and analyses that is consistent across the 

agency(s) (for example, Land Treatment Digital Library; http://greatbasin.

wr.usgs.gov/ltdl/)?

4. Is there a mechanism for summarizing the results and incorporating the relevant information into the planning process?

5. Is there a mechanism to share monitoring results with others implementing 

similar treatments on similar sites? The Joint Fire Science Program’s Great 

Basin Fire Science Delivery Project can assist with this effort (www.gbfiresci.

org).

Monitoring provides essential information on treatment outcomes that can be 

used to adjust future prescriptions and to determine if post-treatment actions are 

needed.
30 USDA Forest Service RMRS-GTR-322. 2014

Selecting the Most 

Appropriate Treatment 

Method

State and Transition Models

State and transition models (STMs) can be used to illustrate potential successional pathways that result from both disturbance and restoration for different 

ecological sites. Appendix 6 provides STMs that represent five generalized ecological types occupied by big sagebrush for the Great Basin and Columbia River 

Plateau. For many areas, specific ecological site descriptions (ESDs) and STMs 

are available. See: http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/

technical/ecoscience/desc/.

Identification and current condition of the specific or generalized big sagebrush 

ecological sites located on the proposed treatment area will help to determine 

which treatments are most appropriate and if treatments are likely to have desired outcomes (Appendix 7). Ecological site descriptions provide information 

on or related to (1) resilience, (2) resistance to invasive annuals species, (3) potential successional pathways following treatment, and (4) potential treatment 

requirements (burning, mechanical treatments, and/or seeding) and outcomes 

(shifts between phases and states).

Land Unit Evaluation Score Sheet

Appendix 8 provides a score sheet that can be used to help evaluate the level of 

ecological site resilience and resistance to invasive annual grasses and to determine the type of treatment and the likelihood of success or failure. Each major 

ecological site (or groups of similar ecological sites) within the proposed treatment area is evaluated with a separate score sheet. Scores are not absolute 

and should be used only as guidelines. The score sheet values can be modified 

when quantitative data and/or scientific studies provide better information or 

when the results of monitoring of similar treatments become available for the 

same ecological sites.

30 USDA Forest Service RMRS-GTR-322. 2014
USDA Forest Service RMRS-GTR-322. 2014 31

1. Mechanical treatments with minimal surface disturbance should be considered when:

a. Resilience and resistant scores are <15 but sufficient perennial herbaceous 

species occur to promote recovery.

b. It is desirable to retain the shrub layer.

c. Species of concern will be more impacted by fire than mechanical 

treatment due to low fire tolerance or change in vegetation structure and 

composition.

2. Prescribed fire can be considered when:

a. Resilience and resistance scores are >20; these are typically cool-moist 

ecological sites occupied by mountain big sagebrush.

b. Large areas need to be treated.

c. Funds are limited.

3. Plant successional pathways on areas being considered for treatment with 

scores between 15 and 20 are more difficult to predict.

a. If the area being evaluated is cool aridic (10 to 12-in ppt) or cool xeric 

(>12-in ppt), then either low to moderate severity prescribed fires or 

mechanical treatments can be considered when sufficient perennial 

herbaceous species exist to promote recovery.

b. If the area being evaluated is dry aridic (<10-in ppt), the use of fire should 

be discouraged.

c. If the area is aridic (10-12-in ppt) and perennial herbaceous vegetation is 

depleted, the use of fire should be discouraged unless reseeding follows 

immediately after the fire and the soil moisture + temperature score is 

>10.

Note that if the area is a priority area for conservation of sage grouse but 

sagebrush cover is a limiting factor at the landscape scale, reseeding or 

transplanting sagebrush should be considered if prescribed fire is used.

4. When predicted successional pathways will not meet the objectives of increasing or restoring resilience to disturbance and resistance to annual 

invasive grasses following treatment, a logical decision is “not to treat.” 

Exceptions include:

a. Critical habitat where sufficient funds exist for repeated interventions, 

and/or integrated strategies can be used such as fire treatments followed 

by control of invasive annual grasses and revegetation.

b. Urban-wildland interface areas where fuels treatments are needed to 

decrease fire risk.

c. Critical portions of a watershed where treatment is necessary to prevent 

erosion or the introduction of an invasive seed-source.
32 USDA Forest Service RMRS-GTR-322. 2014

General Rule—the warmer and drier the proposed treatment area, the greater the 

risk of invasive annual grasses and the more important the residual vegetation is 

for recovery.

Advantages and Disadvantages of Prescribed Fire

The majority of native perennial grasses and forbs are fire tolerant. However, 

mortality can vary widely ranging from <10% to >90% depending upon the 

amount of time that herbaceous plant crowns are exposed to lethal temperatures. Fire intensity (heat released) and duration are influenced by 

weather conditions, fuels, composition and packing of live and dead fuels in 

grass crowns, and topography (fig. 10) (for additional information on fire effects on individual plant species see Fire Effects Information System; http://

www.fs.fed.us/database/feis/).

Advantages—Fire is a natural process and vegetation can respond positively 

given careful selection of the area to be treated. It is often the most economical 

treatment and large areas can be treated. When used to reduce tree encroachment, fire usually results in a longer time interval before retreatment is required 

resulting from the removal of small trees that often survive mechanical treatment. Fire severity can be controlled somewhat by the prescription, which 

includes pre-fire fuel treatments and weather conditions at the time of the fire.

Disadvantages—Fire often results in a greater risk of invasive annual species 

dominance in low to mid elevation sites (mesic and dry-aridic soils). Fire typically results in increased resource availability (for example, nitrogen) in the first 

1-3 years after burning compared to mechanical treatments that have minimal 

to moderate soil disturbance. This flush of nutrients can decrease resistance 

to invasive annuals on sites with favorable climatic conditions. Fire also reduces or eliminates shrubs, especially those that are fire intolerant. Recovery of 

Wyoming big sagebrush following fire in warm-dry ecological sites (mesic/aridic), especially in dry-aridic (<10-in), is very slow to nearly non-existent (Miller 

and others 2013). However, recovery of mountain big sagebrush on cool-moist 

ecological sites typically occurs within 25-35 years. Fire also results in a significant reduction in soil biological crusts that typically contribute a major portion 

of plant cover on mesic/aridic soils and minimize the amount of cheatgrass in 

a plant community. Prescribed fire can include potential liability issues and 

concerns such as smoke, wildlife, and the urban interface. Also, successful 

prescribed fire requires adequate fuels and climate conditions, and additional 

costs can be incurred when a prescribed fire is postponed due to extreme or 

limiting weather conditions, and/or air quality concerns.
USDA Forest Service RMRS-GTR-322. 2014 33

Advantages and Disadvantages of Mechanical 

Treatments

Advantages—Mechanical treatments can maintain a desired level of the shrub 

component and, where applicable, be selective in which trees are targeted. 

Some methods cause minimal soil disturbances such as when cut-and-leave 

treatments are used or tire impact from heavy equipment is minimized. The 

boundaries of the area treated are easily controlled and there is a broad time 

period when treatments can be applied. Liability is minimal and mechanical 

treatments can be successfully used near the wildland urban interface. Light 

surface disturbance also can enhance the seedbed for seedling establishment 

and have minimal impacts on cover of soil biological crusts.

Disadvantages—Mechanical treatments can leave large amounts of woody 

debris following treatment of Phase II to Phase III woodlands and can result 

in high soil disturbance (compaction or soil surface movement) under certain 

conditions. Mechanical treatments typically have a high cost/acre, take longer 

to treat large areas than prescribed fires, and some equipment is limited by 

steepness and roughness of the terrain. Clearance costs on federal lands also 

may be higher per acre compared to prescribed fire, especially for archeological surveys if increased surface disturbance is expected. Mechanical treatments 

such as mowing to establish a fuel break can result in an increase in fine fuels if 

the understory has a significant cheatgrass component.

Seeding Considerations

The decision to seed should be based on (1) ecological site characteristics that 

strongly contribute to degree of success (see fig. 3, seeding success increases 

with resilience), and (2) current composition and structure of native and invasive species.

Ecological Site Characteristics—Seeding success on ecological sites with severely depleted perennial grasses and forbs varies across ecological sites. 

Native seeding success on severely depleted ecological sites with warm-mesic 

to mesic and dry aridic (<10-in precipitation) soil temperature/moisture regimes is extremely low (accumulative soil moisture and temperature score <10) 

(fig. 12). Using introduced wheatgrasses can slightly improve seeding success 

on these sites but may not meet management objectives. Seeding success on 

cool-mesic/aridic ecological site (10-12-in precipitation) is usually mixed, and is 

highly dependent on annual moisture in the first 2-3 years following treatment 

(score = 12-15) (fig. 13). Seeding success on frigid/xeric ecological sites (score = 

14-17) is typically high. Environmental factors such as precipitation timing and 
34 USDA Forest Service RMRS-GTR-322. 2014

amount, which cannot be controlled nor predicted, can affect seeding success 

even on cool mesic/aridic and frigid/xeric ecological sites.

Need and Effect—Potential treatment areas where perennial herbaceous species are absent or severely depleted will need to be seeded post-treatment 

if the ecological site characteristics are suitable for success (cumulative soil 

moisture and temperature usually scores >12). However, for areas with scores 

>10-15 that have sufficient perennial herbaceous species to recover following a prescribed fire or mechanical treatments, seeding with introduced 

species or aggressive cultivars will likely retard or prevent recovery of the native community.

Figure 12. Nine-year post 

wildfire (2002) response for 

adjacent (A) seeded and 

(B) unseeded communities. 

Ecological site is a warmmesic/dry-aridic Wyoming big 

sagebrush/Indian ricegrassSandberg bluegrass, elevation 

5000 ft southeast of Gerlach 

Nevada. Native herbaceous 

vegetation prior to the burn was 

likely severely depleted to absent 

and the presence of a sagebrush 

canopy was unknown. Soil 

moisture + temperature score = 

9, total score 9-12. This site has 

low suitability for seeding and 

low resilience to disturbance. 

The treated site (A) was drill 

seeded to native grasses in the 

fall following the fire and (B) was 

not seeded. Cover in the treated 

site (A) is 0% native deeprooted perennial grasses, 61% 

cheatgrass, 3.3% native shrub 

cover and 6% non-native shrub 

cover. Cover in the untreated site 

(B) is 0% deep rooted perennial 

grasses, 89% cheatgrass, 6.7% 

native shrub cover and 0% nonnative shrub cover.

B

A
USDA Forest Service RMRS-GTR-322. 2014 35

Figure 13. Nine year post wildfire 

(2002) response for adjacent 

(A) seeded and (B) unseeded 

communities. Ecological site is 

a cool-mesic/aridic Wyoming 

big sagebrush/bluebunch 

(10-12-in PZ) south of Rome 

Oregon, elevation 5000 ft. 

Native herbaceous vegetation 

prior to the burn was likely 

severely depleted to absent and 

the presence of a sagebrush 

canopy unknown. Soil moisture 

+ temperature score = 12; total 

score 12-15. Treated (A) was 

drill seeded to native grasses in 

the fall following the fire and (B) 

was not seeded. Cover in the 

treated site (A) is 23% native 

deep-rooted perennial cover 

and 65% cheatgrass, and in the 

untreated site (B) is 7% native 

deep-rooted perennial cover and 

69% cheatgrass.

B

A
36 USDA Forest Service RMRS-GTR-322. 2014

What, where, and how much to treat is usually determined by priorities, potential outcomes, needs, available resources, and funding availability. Questions 

to address when selecting areas to be treated include:

1. What are the chances of success based on the areas resilience to disturbance 

and resistance to invasive species, which are closely linked to ecological site 

characteristics and plant community composition and structure at the time 

of treatment?

2. Does the area provide important habitat for animal and/or plant species of 

concern?

3. Can treatment increase the landscape connectivity for species of concern?

4. Is the proposed treatment area a major source of sediment to nearby 

streams or does it have high erosion potential?

5. What is the treatment cost?

6. Is retreatment likely to be needed and, if so, is it an option?

7. Can post-treatment management be modified to promote attainment of 

project objectives? For example, can livestock grazing be deferred longenough for the site to recover, and can appropriate grazing be implemented 

to maintain the treatment objectives once the decision to graze has been 

made?

36 USDA Forest Service RMRS-GTR-322. 014

Selecting Treatment Areas
USDA Forest Service RMRS-GTR-322. 2014 37

Key References

Chambers, J.C.; Bradley, B.A.; Brown, C.S.; D’Antonio, C.; Germino, M.J.; Grace, J.B.; 

Hardegree, S.P.; Miller, R.F.; Pyke, D.A. 2014. Resilience to Stress and Disturbance, 

and Resistance to Bromus tectorum L. Invasion in Cold Desert Shrublands of Western 

North America. Ecosystems. 17:360-376.

Miller, R.F.; Bates, J.D.; Svejcar, T.J.; Pierson, F.B.; Eddleman, L.E. 2005. Biology, 

ecology, and management of western juniper (Juniperus occidentalis). Tech. Bull. 

152. Corvallis, OR: Oregon State University Agricultural Experiment Station. 77 p.

Miller, R.F.; Bates, J.D.; Svejcar, T.J.; Pierson, F.B.; Eddleman, L.E. 2007. Western juniper 

field guide: asking the right questions to select appropriate management actions. 

Circular 1321. Reston, VA: U.S. Department of the Interior, Geological Survey. 59 p.

Miller, R.F.; Knick, S.T.; Pyke, D.A.; Meinke, C.W.; Hanser, S.E.; Wisdom, M.J.; Hild, 

A.L. 2011. Characteristics of sagebrush habitats and limitations to long-term 

conservation. In: Knick, S.T.; Connelly, J.W. eds. Greater sage-grouse: ecology 

and conservation of a landscape species and its habitats. Berkley, CA: University 

California Press: 38:146-184.

Miller, Richard F.; Chambers, Jeanne C.; Pyke, David A.; Pierson, Fred B.; Williams, C. 

Jason. 2013. A review of fire effects on vegetation and soils in the Great Basin Region: 

response and ecological site characteristics. Gen. Tech. Rep. RMRS-GTR-308. Fort 

Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station. 169 p.

Parson, A.; Robichaud, P.R.; Lewis, S.A.; Napper, C.; Clark, J.T. 2010. Field guide for 

mapping post-fire soil burn severity. Gen. Tech. Rep. RMRS-GTR-243. Fort Collins, 

CO: U.S. Department of Agriculture, Forest Service Forest and Range Experiment 

Station. 49 p.

Pyke, DA. 2011. Restoring and rehabilitating sagebrush habitats. In: Knick, S.T.; Connelly, 

J.W., eds. Greater sage-grouse: ecology and conservation of a landscape species and 

its habitats. Studies in Avian Biology. Berkeley, CA: University of California Press. 

38:531-548.

Shultz, L. M. 2012. Pocket Guide to Sagebrush. PRBO Conservation Science.

Tausch, R.J.; Miller, R.F.; Roundy, B.A.; Chambers, J.C. 2009. Piñon and juniper field 

guide: asking the right questions to select appropriate management actions. Circular 

1335. Reston, VA: U.S. Department of Interior, U.S. Geological Survey. Available at: 

http://pubs.usgs.gov/circ/1335/.

USDA Forest Service RMRS-GTR-322. 2014 37
38 USDA Forest Service RMRS-GTR-322. 2014

Literature Cited

USDA Forest Service RMRS-GTR-322. 2014

Blaisdell, J.P. 1953. Ecological effects of planned burning of sagebrush-grass range on 

the upper Snake River Plains. Tech. Bull. 1075. Washington, DC: U.S. Department of 

Agriculture. 39 p.

Bradley, A.F.; Noste, N.V.; Fischer, W.C. 1992. Fire ecology of forests and woodlands 

in Utah. Gen. Tech. Rep. INT-GTR-287. Ogden, UT: U.S. Department of Agriculture, 

Forest Service, Intermountain Forest and Range Experiment Station. 128 p.

Chambers, J.C; Bradley, B.A.; Brown, C.S.; D’Antonio, C.; Germino, M.J.; Grace, J.B.; 

Hardegree, S.P.; Miller, R.F.; Pyke, D.A. 2014. Resilience to Stress and Disturbance, 

and Resistance to Bromus tectorum L. Invasion in Cold Desert Shrublands of Western 

North America. Ecosystems. 17:360-376.

Chambers, J.C.; Miller, R.F; Board, D.I.; Grace, J.B.; Pyke, D.A.; Roundy, B.A.; Schupp, 

E.W.; Tausch, R.J. [In press]. Resilience and resistance of sagebrush ecosystems to 

management treatments: implications for state and transition models. Rangeland 

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Johnson, D.D.; Miller, R.F. 2006. Structure and development of expanding western 

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Mahalovich, M.F.; McArthur, D.E. 2004. Sagebrush (Artemisia spp.): seed and plant 

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McArthur, E.D. 1983. Taxonomy, origin, and distribution of big sagebrush (Artemisia 

tridentata) and allies (subgenus Tridentatae). In: Johnson, R.L. ed. First Utah Shrub 

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3-11.

Monsen, S.; Stevens, R.; Shaw, N. 2004. Restoring western ranges and wildlands. USDA 

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RMRS-GTR-136.

Mueggler, W.F.; Blaisdell, J.P. 1958. Effects on associate species of burning, rotobeating, 

spraying, and railing sagebrush. Journal of Range Management 11:61-66.
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Nord, E.C. 1965. Autecology of bitterbrush in California. Ecological Monographs 35:307-

334.

Parson, A.; Robichaud, P.R.; Lewis, S.A.; Napper, C.; Clark, J.T. 2010. Field guide 

for mapping post-fire soil burn severity. RMRS-GTR-243. U.S. Department of 

Agriculture, Forest Service Forest and Range Experiment Station. 49 p.

Pechanec, J.F.; Stewart, G. 1954. Sagebrush burning good and bad. Farmers’ Bull. 1948. 

Washington, DC: U.S. Department of Agriculture. 32 p.

Pyke, and others. [In progress]. Field Guide for Restoration of Sagebrush-Steppe: 

Ecosystems with Special Emphasis on Greater Sage-grouse Habitats.

Pyle, W.H.; Crawford, J.A. 1996. Availability of foods of sage grouse chicks following 

prescribed fire in sagebrush-bitterbrush. Journal of Range Management 49:320-324.

Riegel, G.M.; Miller, R.F.; Smith, S.E.; Skinner, C. 2006. The history and ecology of fire in 

northeastern Plateaus bioregion. In: Sugihara, N.G.; Borchert, M.; van Wagtendonk, 

J.W.; Shaffer, K.E.; Fites-Kaufmann, J.; Thode, A.E. eds. Fire in California ecosystems. 

Berkeley, CA: University California Press: 225-263.

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and adjacent big sagebrush ranges in North Park, Colorado. Journal of Range 

Management 19:17-20.

Rosentreter, R. 2004. Sagebrush identification, ecology, and palatability relative to 

sage-grouse. In: Shaw, N.L.; Pellant, M.; Monsen, S.B., comps. Sage-grouse habitat 

restoration symposium Proceedings. Proc. RMRS-P-38. Fort Collins, CO: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station: 3-15.

Roundy, B.A.; Miller, R.F.; Tausch, R.J.; Young, K.; Hulet, A.; Rau, B.; Jessop, B.; 

Chambers, J.C.; Egget, D. [In press]. Understory cover responses to piñon-juniper 

treatments across tree dominance gradients in the Great Basin. Journal of Range 

Ecology and Management.

Shultz, L.M. 2009. Monograph of Artemisia subgenus tridentata (AsteraceaeAnthemideae). Systematic Botany Monographs 89: 131.

Shultz, L.M. 2012. Pocket Guide to Sagebrush. PRBO Conservation Science.

USDA Forest Service. 2013. Fire effects information system. http://www.fs.fed.us/

database/feis/plants/index.html

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a basic system of soil classification for making and interpreting soil surveys. 

Agriculture Handbook No. 436. Available at: ftp://ftp-fc.sc.egov.usda.gov/NSSC/

Soil_Taxonomy/tax.pdf.

USDA Natural Resources Conservation Service [USDA-NRCS]. 2011. Major land 

resource regions custom report. USDA Agricultural Handbook 296 (2006). Available 

at: http://soils.usda.gov/MLRAExplorer.

USDA-NRCS. Big Sagebrush: Plant Guide. Plant Fact Sheet/Guide: 1-12. Available at 

http://plants.usda.gov
40 USDA Forest Service RMRS-GTR-322. 2014

Volland, L.A.; Dell, J.D. 1981. Fire effects on Pacific Northwest forest and range 

vegetation. Range Management and Aviation and Fire Report. Portland, OR: U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Region 6: 23 p.

West, N.E. 1983a. Overview of North American temperate deserts and semi-deserts. In: 

West, N.E. ed. Temperate deserts and semi-deserts. Amsterdam, the Netherlands: 

Elsevier Publishing Company: 321-330.

West, N.E. 1983b. Western Intermountain sagebrush steppe. In: West, N.E. editor. 

Temperate deserts and semi-deserts. Amsterdam, the Netherlands: Elsevier 

Publishing Company: 351-374.

West, N.E. 1994. Effects of fire on salt-desert shrub rangelands. In: Monsen, S.B.; Kitchen, 

S.G. editors. Proceedings—Ecology and Management of Annual Rangelands. INTGTR-313. U.S. Department of Agriculture, Forest Service, Intermountain Forest and 

Range Experiment Station: 71-74.

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Barbour, M.G.; Billings, W.D. eds. North American terrestrial vegetation. Second 

edition. Cambridge, UK: Cambridge University Press: 255-284.

Wright, H.A. 1972. Shrub response to fire. In: McKell, C.M.; Blaisdell, J.P.; Goodin, J.R. 

eds. Wildland shrubs—Their biology and utilization. INT-GTR-1. U.S. Department 

of Agriculture Forest Service Intermountain Forest and Range Experiment Station: 

204-217.

Wright, H.A.; Neunshwander, L.F.; Britton, C.M. 1979. The role and use of fire in 

sagebrush and pinyon-juniper communities. Gen. Tech. Rep. INT-GTR-58. Ogden, 

UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range 

Experiment Station. 48 p. 
USDA Forest Service RMRS-GTR-322. 2014 41

Appendix 1. Primary components and characteristics (from figures 

1 and 3) that influence resilience to disturbance, resistance to 

invasive annual grasses, and successional trajectories.

Component Attributes

Ecological site (figs.1, 3 and 4)

Regional location (MLRA)

Climate

Topography

• Elevation, aspect, slope, landform and landscape position (consider how 

topography effects water movement & storage, & heat loads)

Soils

• Soil moisture and temperature regimes

• Depth, texture, % organic matter, structure (consider factors that influence water 

storage and availability)

Potential vegetation within the reference state

• Species composition and structure (e.g., biomass, cover, density, etc.)

• Potential production in favorable, average and unfavorable years 

Current vegetation

Vegetation productivity (annual production)

Species composition and structure relative to the ecological site description

• Fire tolerant & non-tolerant species (morphology)

• Native & invasive species

• Residual perennial herbaceous species are often more important for 

recovery than seed banks and seed sources

• Potential for invasive species 

• Environmental characteristics of the site (e.g., mesic to warm frigid; s-facing 

slopes

• Relative abundance of perennial herbaceous species

• On site and adjacent invasive seed banks and potential seed rain

Fuel load and structure

• Woodland phase (fire severity increases with increased tree biomass)

• Fine surface fuels and structure (biomass, continuity, packing ratios)

Woodland age structure (pre- and post-settlement tree densities)

Amount and distribution of bare ground (gap size between perennial plants)Amount 

and distribution of biological soil crusts

At-risk-phase?

Disturbance history (figs. 1 and 

3; pre- and post)

Severity and frequency

Time since last event 

Type

• Fire

• Mechanical

• Drought

• Herbivory, including livestock, native and introduced herbivores 

• Disease, snow-mold, fungus, etc.

• Insects

Fire severity (fig. 10)

Fuels

Topography 

Fire weather

Season (linked with fire weather and plant phenology)

Current vegetation (fuel abundance and structure)

Fire type

• Ground, surface, crown, head fire, backfire and backing fire

Pre-treatment weather (previous 

1-3 years)

Timing and amount of precipitation

Temperatures (primarily extremes) Consider how it has influenced

• Fuels

• Seed banks

• Pre-treatment species composition
42 USDA Forest Service RMRS-GTR-322. 2014

Appendix 2: Soil temperature and moisture regimes and general 

ranges in elevation for indicator plant species in the Great Basin 

and Columbia River Plateau regions. Examples are shown for 

the Malheur High Plateau (MLRA23) and Central Nevada Basin 

and Range (MLRA 28B). Considerable variability exists within an 

MLRA so multiple indicators should be used. 

Soil 

temperature 

regime

Elevation (ft)a PPT 

(in)

Moisture 

regime Indicator plantsb Ecological zones

MLRA 23 MLRA 28B

Mesic

Warm <3000 4000-6000 4-8 Typic Aridic Arsp, Atco, Krla, 

Heco, Achy Desert basins

Cool 3000-4000 5500-6500 8-12 Aridic 

bordering Xeric

Arno, Artrw, (few 

Juos or Juoc), Acth

Sagebrush semidesert

Frigid

Warm 4000-5000 6000-8000 12-14 Xeric bordering 

Aridic

Arno, Arar, Artrv, 

Artrw, Juos or Juoc, 

Acth

Upland 

sagebrush, juniper

Cool 5000-6000 7500-8200 14+ Typic Xeric

Artrv, Symph, Amal, 

Pimo, Feid, Acne, 

snow pocket Potr

Upland mountain 

sagebrush

Cryic

Warm 6000-7500 

(8000) 8200-9600 16+ Typic Xeric

Artrv, Arsp, Arar, 

Symph, Amal,Cele, 

Abco, Potr

Mountain brush

Cool 8000-9000 9300-10,600 18+ Typic Xeric Pien, Piar, Pifl High mountain

Cold >9000 10,600-13,061 20+ Xeric bordering 

Aridic Alpine plants Subalpine and alpine

a Elevation is usually adjusted 500 ft for north (-) or south (+) aspects, and elevation breaks change from north to the south 

ends of the MLRA. Elevation and indicator species should be fine-tuned for a specific management area. It is also important to 

consider that changes along elevation gradients or from north to south locations within an MLRA are usually gradual and are 

not defined by distinct boundaries. 

b Plant codes: Abco=Abies concolor, Achy=Achnatherum hymenoides, Acne=Acnatherum nevadense, Acth=Achnatherum

thurberianum, Amal=Amelachier alnifolia, Arar=Artemisia arbuscula, Arno=Artemisia nova, Arsp=Artemisia spinescens, 

Artrv=Artemisia tridentata spp. vaseyana, Artrw=Artemisia tridenatata spp. wyomingensis, Atco=Atriplex confertifolia, 

Cele=Cercocarpus ledifolius, Feid=Festuca idahoensis, Heco=Hesperostipa comata, Juoc=Juniperus occidentalis, 

Juos=Juniperus osteosperma, Krla=Krascheninnikovia lanata, Piar= Pinus aristata, Pifl=Pinus flexilis, Pimo=Pinus monophylla, 

Symph=Symphoricarpos sp., Potr=Populus tremuloides.
USDA Forest Service RMRS-GTR-322. 2014 43

Appendix 3. What is the meaning of a soil family name? 

Soil Family Names

In general, soil family names ending in “olls” are Mollisols indicating that they have a minimum of 1% organic matter. Soils 

ending in “ids” are Aridisols. They contain <1% organic matter, usually occur in aridic precipitation zones, and are less 

productive than Mollisols. Both soil orders are common in the Great Basin. Examples of naming protocols for Mollisols and 

Aridisols follow.

1 Course sandy loam mixed mesic aridic Typic Haploxerolls

2 Clayey smectic frigid lithic xeric Haplargids

3 Fine loamy mixed super active xeric Argicryolls

4 Loamy skeletal mixed frigid Pachic Haploxerolls

Soil texture / temperature / moisture

Soil 1: Warm (mesic) dry (aridic) soil with an aridic moisture regime that is approaching xeric (xer for xeric) or 12 inches 

precipitation (PPT). This soil has the lowest potential resilience to disturbance and resistance to invasives due to its’ 

mesic-aridic soil temperature-moisture regime.

Soil 2: A cool (frigid), moist (xeric), shallow (lithic) soil with an accumulation of clay in the B horizon (argi for argillic layer) 

and >12 in PPT. This soil has the lowest potential infiltration rates due to the presence of an argillic layer and the 

lowest storage potential due to a shallow soil depth (lithic = shallow) and <1% organic matter content.

Soil 3: A cold (cry for cryic), moist (xeric, >12 in PPT) soil with an accumulation of clay in the B horizon (argi). This soil has 

the highest potential resistance to invasive species due to the cold temperature regime. Potential resilience will usually 

decline along a gradient from warm-cryic to cold-cryic as a result of a shortened growing season.

Soil 4: A moist (xer), cool (frigid), rocky (skeletal) soil. This soil has relatively high resilience and moderate resistant to 

invasives. It has the highest water capture potential of the four soils due to the loamy soil texture and lack of an argillic 

layer. 

Soil Terms

Arigillic—typically defined by percent increase in alluvial clay content (usually the B horizon) relative to the overlying soil 

layer (usually the A horizon). The increase in clay and abrupt change in texture can substantially reduce infiltration 

rates.

Duripan—a subsurface horizon that is cemented by alluvial (water transported) silica to the degree that fragments from 

the air-dry horizon do not slake (take in water or crumble) during prolonged soaking.

Lithic—shallow soils over a paralithic (soft bedrock) contact or duripan (subsurface horizon cemented by bedrock).

Skeletal—soils with >35% particle sizes >2 mm by volume.

Soil depth—very shallow <10 in; shallow 10-20 in; moderately deep 20-36 in; deep >36 in.

Soil moisture regime—an important soil property that, in combination with growing season soil temperature, influences 

plant growth and biological soil processes. The moisture regime is based on the amount of soil moisture available 

during the growing season in areas with moist-cool winters and hot-dry summers. Although mapped as distinct breaks 

in precipitation (<12 in or >12 in), soil moisture regimes are continuous gradients changing with location and elevation. 

Thus, it is important to consider where the site fits along the gradient. For example, a site with an aridic moisture 
44 USDA Forest Service RMRS-GTR-322. 2014

regime that receives 11.5 in of precipitation will often be more resilient to disturbance than an aridic site receiving 9 in 

of precipitation. For a detailed definition and description for each soil moisture regime see USDA-NRCS 1999. For this 

field guide, we define the following soil moisture regimes:

a. Dry-Aridic <10 in 

b. Aridic—10-12 in Xeric – 12-14 in

c. Moist xeric—>14 in

Soil temperature regime—an important property of a soil that, along with soil moisture, influences plant growth and 

biological soil processes. Soil temperature is usually measured at 50 cm depth (20 inches) (or depth at the lithic or 

paralithic contact), which is considered deep enough to reflect seasonal temperatures and not daily cycles. Since 

measurements of seasonal soil temperatures are spatially limited across the Great Basin, soil temperature regimes are 

estimated based on seasonal air temperatures, which are largely influenced by location, elevation, and aspect. When 

soils are mapped, temperature regimes are most commonly based on elevation and aspect, which are adjusted for 

each sub-region (MLRA). For a detailed definition and description for each soil regime, see USDA-NRCS 1999.

a. Mesic (warm)—indicator species are Wyoming big sagebrush and black sagebrush. Mesic soils have low relative 

resistance to invasives compared to frigid and cryic soils. They also are considered to have lower resilience.

b. Frigid (cool)—indicator species are mountain big sagebrush, piñon pine, and low sagebrush on shallow soil, but 

black sagebrush and occasionally Wyoming big sagebrush may occur on the warmer end of this soil regime or 

where soil moisture is limiting. Resilience to disturbance and resistance to invasive species are higher than on 

mesic soils.

c. Cryic (cold)—cryic soils are cooler in summer than frigid soils. Indicator species are curleaf mountain mahogany, 

white and grand fir, limber pine, lodgepole and white bark pine, which typically intermingle with mountain big and 

low sagebrush. Resilience is high on the warm end of this regime, but declines as temperatures become colder 

due to limitations on plant growth. Resistance to invasive species is higher than for mesic and likely frigid soils 

(although data are limited).
USDA Forest Service RMRS-GTR-322. 2014 45

Appendix 4a: Characteristics that differentiate post and presettlement woodlands. There are several types of woodlands 

based on stand age in the Great Basin and Columbia River 

Plateau region. These include: (1) old-growth woodland; 

(2) woodland that was formerly old growth, but that is currently 

occupied by young trees (< 150 years old) as a result of a stand 

replacing disturbance; (3) tree shrub savanna where the old trees 

are less than 10% canopy cover; (4) tree shrub savanna that is 

infilled by post-settlement young trees; and (5) sagebrush shrubsteppe occupied by young trees.

Woodland Characteristics and Tree Growth Form

Characteristic Post-Settlement Trees Pre-Settlement Trees

Juniper crown shape Conical with point tip Flattened, rounded, or uneven tops 

Piñon crown shape Conical with pointed to slightly rounded tip Flattened, rounded, or uneven top

Juniper branch structure Branches get progressively smaller from 

bottom to top of tree

In open stands, large branches near the base

Piñon branch structure Branches become smaller from bottom to top 

of tree, general orientation is vertical

In open stands branches large near base and 

remain relatively large well into the crown, 

more randomly oriented

Juniper bark Flaky, relatively thin with limited or shallow 

vertical furrows

Thick, fibrous with well-developed vertical 

furrows

Piñon bark Relatively thin, flaky, with weak vertical 

furrows

Thicker, more plate-like structure than 

furrowed

Juniper leader growth Terminal leader growth in the upper 1/4 of 

the tree usually >2 in. In open stands, leader 

growth >2 in from bottom to top

Leader growth in the upper 1/4 of the tree 

usually <1 in

Piñon leader growth Leader growth in piñon similar to juniper but 

not directly visible. Must look for bud scale 

scares to determine length

Leader growth in upper 1/4 of the tree usually 

<2 in.

Tree canopy lichen Little or no foliose lichen on juniper Juniper often covered by bright green foliose 

lichen

Dead wood in standing tree Little dead wood in bole, few to no dead 

trees, logs, or large stumps

Dead branches, bark missing, black stain 

and/or black lichen

Large wood across the site Large diameter logs and stumps absent Large diameter logs and stumps, often 

charred, scattered across the site
46 USDA Forest Service RMRS-GTR-322. 2014

Appendix 4b. Photos showing examples and comparisons 

between old and young trees.

75 yrs 150 yrs 270 yrs

Utah	
  

Juniper	
  

Western	
  

Juniper	
  

4b. Bark on western and Utah 

juniper is typically flaky and thin on 

trees <130-150 years. Bark on trees 

around 150-180 years is thicker and 

beginning to develop vertical 

furrows. On trees >200 years 

furrows continue to develop and the 

bark becomes very fibrous (usually 

around >250 years). (Photos of Utah 

juniper by Robin Tausch) 
USDA Forest Service RMRS-GTR-322. 2014 47

(A) Bark on singleneedle piñon pine is relatively thin and flaky, and weak vertical furrows occur on 

trees <130 years. (B) Trees >300 years have thicker bark that is more plate-like than furrowed. (Photos 

by Robin Tausch). 

A	
   B	
  

Yellow-­‐green	
  

foliose	
  lichen	
  

Black	
  lichen	
  

Black	
  stain	
  

These old western (A) and Utah (B) junipers have multiple old-growth characteristics including yellow-green foliose lichen (on the western 

juniper), black lichen and black stain (often mistaken for charred wood), dead wood including part of the trunk, and very limited leader 

growth at the branch tips. The bark is deeply furrowed and very fibrous. 

A	
   B	
  
48 USDA Forest Service RMRS-GTR-322. 2014

Both Utah (A) and western (B) 

juniper exhibit flattened or rounded 

crowns sometimes with dead tops, 

twisted trunks, very limited terminal 

and lateral growth on the branch 

tips, and bark that is thick, furrowed 

and fibrous. Singleneedle pinyon

pine (C) exhibits dead branches, 

thick platy bark, and a flattened 

round crown. (Photos A and C by 

Robin Tausch) 

A	
  

B	
  

A	
  

C	
  

Low density of old trees killed by fire that would have formed a savannah with understories of (A) mountain big sagebrushbitterbrush/Idaho fescue and (B) Wyoming big sagebrush/needlegrass. Both communities have more than a 10-fold increase 

in young trees compared to pre-burn densities. Size and density of snags, stumps, and logs can help project stand structure 

prior to the fire. (A) Fire occurred around 1900. (B) Time since fire in unknown. (Photo B by Robin Tausch) 

A	
   B	
  
USDA Forest Service RMRS-GTR-322. 2014 49

Appendix 5. Post-burn indicators of fire severity. Soil and litter 

indicators are derived from Parson and others (2010).

Low severity Moderate severity High severity

>75% burned sagebrush 

skeletons remaining

15-75% burned sagebrush skeletons 

remaining

Sagebrush basal stumps remain or burned 

below the soil surface

<25% tree foliage dead, <15% 

foliage consumption

25-75% tree foliage dead, 15-50% 

foliage consumed

>75% tree foliage dead, >50% consumed

Tree duff blackened but little 

consumed

Majority of tree duff consumed surface 

blackened

White ash layer beneath tree canopy

>2 in blackened stubble remains 

on burned grasses

0.25-1in blackened stubble remains on 

burned grasses

Grass crowns consumed 

to or below the surface

Unburned patches >50% Unburned patches 15-50% Unburned patches <15%

Interspace litter consumption 

<50%

Interspace litter consumption 50-80% Interspace litter consumption

 >80%, white ash deposition

Shrub canopy litter consumption 

< 50%

Shrub canopy litter consumption 50-

80%

Shrub canopy litter consumption >80%, 

white ash deposition

No ash, ground fuels blackened & 

recognizable

Thin layer of black to gray ash, some 

litter recognizable

Layer of powdery gray or white ash >90% 

surface organics consumed

No fire induced water repellency Weak to medium water repellency at or 

just below the surface

Strong water repellency at or below the 

surface

Surface soil structure unchanged Surface structure slightly to not altered Aggregated stability reduced or destroyed, 

surface loose and/or powdery
50 USDA Forest Service RMRS-GTR-322. 2014

These STMs represent groupings of ecological types that are occupied by 

Wyoming or mountain big sagebrush, span a range of soil moisture-temperature regimes (warm-dry to cold-moist), and characterize a large portion of the 

Great Basin and Columbia River Plateau regions: (A) Mesic/aridic Wyoming big 

sagebrush in an 8-12-in precipitation zone (PZ); (B) Cool mesic to warm frigid/

xeric frigid mountain big sagebrush in a 12-14-in PZ; (C) Cryic/xeric mountain 

big sagebrush/mountain brush in a 14+ in PZ; (D) Cool mesic to warm frigid/

xeric mesic big sagebrush with piñon pine and juniper potential in a 12-14-in 

PZ, and (E) Cool frigid/xeric mountain big sagebrush with piñon and juniper 

potential in a 12-14+ in PZ. Large boxes illustrate states that are comprised of 

community phases (smaller boxes). Transitions among states are shown with 

arrows starting with T; restoration pathways are shown with arrows starting 

with R. The “at risk” community phase is most vulnerable to transition to an 

alternative state.

Appendix 6. State-and-transition models (STMs) for five 

generalized ecological types for big sagebrush.
USDA Forest Service RMRS-GTR-322. 2014 51
52 USDA Forest Service RMRS-GTR-322. 2014
USDA Forest Service RMRS-GTR-322. 2014 53
54 USDA Forest Service RMRS-GTR-322. 2014
USDA Forest Service RMRS-GTR-322. 2014 55

Perennial	
  grass/forb	
  

Root	
  sprouNng	
  

shrubs/sagebrush	
  

Sagebrush/root	
  

sprouNng	
  shrubs	
  

Perennial	
  grass/forb	
  

1a	
  

6E	
  -­‐	
  Cryic/xeric	
  mountain	
  big	
  sagebrush/	
  

Mountain	
  brush	
  (14	
  in	
  +	
  PPT)	
  

Moderately	
  high	
  resilience	
  and	
  high	
  resistance	
  

1b	
  

Reference	
  state	
  

Root-­‐sprouNng	
  

shrubs/forbs	
  

Perennial	
  grass	
  rare	
  

Shrub/Forb	
  state	
  

Sagebrush/root	
  

sprouNng	
  shrubs	
  

Perennial	
  grass/forb	
  	
  

rare	
  

Shrub	
  state	
  

T2	
   T3	
  

T4	
  

R2	
   R3	
  

5	
  

(1a)	
  Perennial	
  grass/forb	
  increases	
  due	
  to	
  

disturbances	
  that	
  decrease	
  sagebrush	
  like	
  

wildfire,	
  insects,	
  disease,	
  and	
  pathogens.	
  

(1b)	
  Sagebrush	
  and	
  other	
  shrubs	
  increase	
  

with	
  Nme.	
  	
  	
  

(T2)	
  Improper	
  grazing	
  triggers	
  a	
  shrub	
  

dominated	
  state.	
  

(R2)	
  Proper	
  grazing	
  results	
  in	
  a	
  return	
  to	
  the	
  

reference	
  state.	
  	
  	
  

(T3	
  and	
  T4)	
  Fire	
  or	
  other	
  disturbances	
  that	
  

remove	
  sagebrush	
  result	
  in	
  dominance	
  by	
  

root-­‐sprouNng	
  shrubs	
  and	
  an	
  increase	
  in	
  

naNve	
  forbs	
  like	
  lupines.	
  	
  	
  

(R3)	
  Proper	
  grazing	
  and	
  Nme	
  result	
  in	
  return	
  

to	
  the	
  reference	
  state.	
  	
  

Note:	
  Resilience	
  is	
  lower	
  on	
  cold	
  cryic	
  sites	
  

due	
  to	
  short	
  growing	
  seasons.
56 USDA Forest Service RMRS-GTR-322. 2014

Appendix 7. Examples of states, phases, and transitions 

following prescribed fire or mechanical treatment for three 

general ecological types in different phases (photos from 

SageSTEP plots; PZ = precipitation zone). For interpretation of 

resilience scores see Appendix 9.
USDA Forest Service RMRS-GTR-322. 2014 57

Fire

↑

Fire

↑

Fire resistant bluebunch wheatgrass is abundant, Sandberg bluegrass fills the interspaces, and cheatgrass is only a trace. 

Although warm-mesic aridic, the area has a high probability for a successful outcome with fire or mechanical treatment. 

Resilience score = 20 

7A—Warm-mesic/aridic

Wyoming big sagebrush/bluebunch wheatgrass-Sandberg bluegrass 

(8-12-in PZ)

Reference State

7B—Warm-mesic/aridic

Wyoming big sagebrush/bluebunch wheatgrass-Indian ricegrass 

(8-12-in PZ)

Invaded State

Severely depleted and cheatgrass cover near 5%. Following a prescribed fire invasive annuals dominate the understory. 

Resilience and resistance to invasive annuals and potential seeding success is low. Resilience score = 9 

2009 2012

2008 2010
58 USDA Forest Service RMRS-GTR-322. 2014

↑

↑

↑

Reference State

Phase I woodland/sagebrush/perennial grass/

forb

Near reference state: bluebunch wheatgrass is 

abundant and cheatgrass only a trace. The area has 

a high probability for a successful outcome with fire or 

mechanical. Resilience score = 20 

Eroded State

Phase III woodland 

Shrubs & perennial herbs rare

Recovery of this site is questionable. Native herbs present but severely depleted and cheatgrass seed source present. Posttreatment management will be critical. Resilience score = 14 

7C—Cool mesic/aridic

Basin & Wyoming big sagebrush/bluebunch wheatgrass (10-12-in PZ)

Juniper potential

Mechanical

Mechanical

Fire

Sagebrush/perennial grass phase

Grassland phase
USDA Forest Service RMRS-GTR-322. 2014 59

Fire↑

7D—Cool frigid/xeric

Mountain big sagebrush/Idaho fescue (12-14-in PZ) 

Juniper potential

Reference State

The presence of Idaho fescue indicates this is a cool-frigid soil temperature regime. The herbaceous layer is dominated by 

native grasses and forbs. There is only a trace of invasive annuals. Nearly 100% sagebrush mortality was caused by Aroga 

moth prior to the prescribed fire. The combination of good herbaceous plant composition + soil moisture/temperature regimes 

results in high resilience and resistance. Fire or mechanical control can be used on this site, particularly since the sagebrush 

cover is gone. However, the lack of ladder fuels will make it difficult to kill the trees with fire. On this site, some mechanical 

preparation was required to carry the fire into the tree canopies. Resilience score = 25.
60 USDA Forest Service RMRS-GTR-322. 2014

Appendix 8a. 

Evaluation sheet for ecological sites within the proposed treatment area to 

evaluate resilience after disturbance and resistance to invasives if the treatment is implemented based on soil temperature and moisture indicators 

and current plant composition. Evaluation scores based on soil moisture and 

temperature indicators can be used to determine site suitability for seeding 

following treatment.
USDA Forest Service RMRS-GTR-322. 2014 61

Score sheet for resilience to management treatment and resistance to annual invasives

Very low = < 10, Low = 10 to < 15, Moderate = 15-20, High = 20

Ecological site name ______________________ Stand (plot)a

Site characteristics Variable 1 2 3 4 5

% of Area estimated

Temperature

Soil temperature regime mesic = 1, frigid = 2, cryic = 3

At the warm or cool end of 

the regime

warm = 1 (if warm cryic = 3), mid = 2, cool = 3 (if 

cool cryic = 1)

Subspecies of sagebrush Wyoming, low, and black = 1, Basin = 2, Mt = 3

 *Total Temperature

Moisture 

Precipitation < 10-in = 1, 10-12-in = 2, 12-14-in = 3, >14-in = 4 

Soil texture Clay = 1, sandy = 1, silty = 1, silty, sandy or clay 

loams = 2, loam = 3

Soil depth1 very shallow = 0 (<10-in), shallow = 1 (10-20-in), 

moderately deep = 3 (20-36-in)

 *Total moisture

Total Moisture + 

Temperature

If score is <10 seeding is extremely risky

Current vegetation (CV): 

Native perennial grasses 

(PG) and forbs (PF)

weighted score x 3 

Scarce to severely 

depleted; <2-3/m2 = 0 0

PG depleted; <3 per m2

and/or codominant with 

BRTE = 2

6

PG & PF dominant = 3 9

Trt severity (TS)

% = survival of perennial 

herbaceous vegetation

Low severity prescribed fire or mechanical 

treatment = CV x 95%

Moderate severity prescribed fire or mechanical 

treatment = CV x 80%

High severity prescribed fire = CV x 20%

*Adjusted CV = CV x TS

Total resilience score *Total temp + *Total moisture + *Adjusted CV = 

resilience score

a The stand or plot should be uniform in topography and soils, and fit within one ecological site.
62 USDA Forest Service RMRS-GTR-322. 2014

Appendix 8b. Definitions for Land Unit Evaluation Sheet.

Resilience (potential recovery) score sheet

Very low = <10, Low 10-<15, Moderate 15-20, High = 20

Score

Site characteristics Variable min max Definition

% of treatment area 

within an ecological 

site

estimated Percentage of area proposed to be treated composed 

of a particular ecological site is estimated. 

Temperature

Soil temp regime mesic = 1, frigid = 2, cryic 

= 3 1 3 Based on guidelines for each MLRA (see Appendix 2)

Is the site at the warm 

or cool end of the 

regime?

warm = 1, mid = 2, cool 

= 3 (warm cryic = 3, cool 

cryic = 1) 1 3

Refer to Appendix 2 to adjust for elevation. Elevation 

is usually adjusted for aspect. For example in 

MLRA23, frigid = 4000-6000 ft + 500 ft for north (-) or 

south (+).

Subspecies of 

sagebrush

Wyoming, low, and black = 

1, Basin = 2, Mt = 3 1 3

Wyoming Big Sagebrush, Black Sagebrush, and Low 

Sagebrush = 1; Basin big sagebrush = 2; Mountain 

big sagebrush = 3

Moisture

Precipitation <10-in = 1, 10-12-in = 2, 

12-14-in = 3, >14-in = 4 1 4

Soil texture Clay = 1, sandy = 1, silty = 

1, silty, sandy or clay loams 

= 2, loam = 3

1 3

Loams have good infiltration rates and water storage 

capacity for plant growth.

Soil depth1 very shallow = 0 (<10-in), 

shallow = 1 (10-20-in), 

mo in

0 3

Soil depth is one of the major variables in 

determining water storage capacity and rooting 

depth.

Current vegetation 

(CV)

weighted score x 3 Score is weighted so importance is equal to moisture 

regime plus temperature regimes.

Perennial grasses 

and forbs

Perennial species that would be expected to be 

dominant to co-dominant within the reference state.

Absent to severely 

depleted = 0 0 0 0

PG < 2/m2 for xeric and < 3/m2 for aridic; invasives 

dominant or, if invasives are not dominant, woody 

species (shrubs or trees) are near maximum cover. 

Depleted or 

codominant with 

BRTE = 2 6 6 6

Abundance of PG and PF are near or equal to 

abundance of invasives (annual exotic abundance is 

highly variable with moisture). If invasives have low 

abundance (< 5% cover), PG >2/m2 for xeric and 

> 3/m2 for aridic.

Dominant = 3 9 9 9 Native herbaceous species are dominant on the site.

Trt severity

% = survival of 

perennial herbaceous 

vegetation

Low severity prescribed fire 

or mechanical treatment = 

CV x 95%

0 8.1

Mechanical treatments that have a high degree of 

disturbance on the soil surface can have moderate 

severity.

Moderate severity 

prescribed fire or 

mechanical treatment = CV 

x 80%

Phase I and II woodlands and high density 

shrublands can burn at moderate severity depending 

on prescription.

High severity fire = CV x 

20%

Phase III woodlands usually burn at high severity.

Total min and max 5 27.1
USDA Forest Service RMRS-GTR-322. 2014 63

Appendix 8c. Example: Wyoming big sagebrush/Thurber 

needlegrass community (Appendix 6—mesic/aridic Wyoming big 

sagebrush (8-12-in PPT State and Transition model in variable 

condition and burned in a wild fire of varying severity.

Resilience ratings based on score sheet.

Example: Potential vegetation on this ecological site is Wyoming big sagebrush and Thurber needlegrass. Soil temperatures 

vary from warm mesic to cool mesic depending on elevation and aspect. Mean annual precipitation is 10-12 in. Soils are 

moderately deep clay loams. Current vegetation ranges from severely depleted on approximately 65% of the area and 

native perennial grasses and forbs dominating the understory on 15% of the area. Fire severity varied from low to moderate. 

Resilience on the majority of the area (75%) is very low to low. The only area where resilience is moderate to approaching high 

is where native perennial herbaceous vegetation is dominant.
64 USDA Forest Service RMRS-GTR-322. 2014

Trt severity (TS)

% = survival of perennial herbaceous 

vegetation

Low severity prescribed fire or 

mechanical treatment = CV x 95% X X

Moderate severity prescribed fire 

or mechanical treatment = CV x 

85%

X X

High severity fire = CV x 20% X

*Adjusted CV = CV x TS

Total Resilience Score *Total Temp + *Total Moisture + 

*Adjusted CV = resilience score 6 15.3 2.2 13.6 18

aThe stand or plot should be uniform in topography and soils, and fit within one ecological site.

Score sheet for resilience to disturbance and resistance to annual invasives

Very low = < 10, Low = 10 to < 15, Moderate = 15-20, High = 20

Ecological site name ______________________ Stand (plot)a

Site characteristics Variable 1 2 3 4 5

% of Area estimated 40 10 25 10 15

Temperature

Soil temperature regime mesic = 1, frigid = 2, cryic = 3 1 1 1 1 1

At the warm or cool end of the regime warm = 1 (if warm cryic = 3), mid 

=2, cool=3 (if cool cryic = 1) 1 2 1 2 2

Subspecies of sagebrush Wyoming, low, and black = 1, Basin 

= 2, Mt = 3 1 1 1 1 1

 *Total Temperature

Moisture 

Precipitation < 10-in = 1, 10-12-in = 2, 12-14-in = 

3, >14-in = 4 2 2 2 2 2

Soil texture Clay = 1, sandy = 1, silty = 1, silty, 

sandy or clay loams = 2, loam = 3 2 2 2 2 2

Soil depth1 very shallow = 0 (<10-in), shallow 

= 1 (10-20-in), moderately deep = 

3 (20-36-in)

3 3 3 3 3

 *Total moisture

Total Moisture + Temperature If <10 seeding extremely risky 10 11 10 11 11

Current vegetation (CV): 

Native perennial grasses (PG) and forbs (PF)

weighted score x 3

Scarce to severely depleted; <2-3/m2 = 0 0 0 0

PG depleted; <3 per m2 and/or codominant 

with BRTE = 2 6 6 6

PG and PF dominant = 3 9 9
USDA Forest Service RMRS-GTR-322. 2014 65

At-risk phase—a community phase that is most vulnerable to transition to an alternative state (for 

example, least resilient). See definition of phase below.

Ecological site—An ecological site (ES) is a conceptual division of the landscape that is defined as a 

distinctive kind of land based on recurring soil, landform, geological, and climate characteristics that 

differs from other kinds of land in its ability to produce distinctive kinds and amounts of vegetation and 

in its ability to respond similarly to management actions and natural disturbances; similar to ecological 

type used by USDA Forest Service and the old term used by the NRCS.

Ecological site descriptions (ESD)—The documentation of the characteristics of an ecological site. 

The documentation includes the data used to define the distinctive properties and characteristics 

of the ecological site; the biotic and abiotic characteristics that differentiate the site (i.e., climate, 

physiographic, soil characteristics, plant communities); and the ecological dynamics of the site that 

describe how changes in disturbance processes and management can affect the site. An ESD also 

provides interpretations about the land uses and ecosystem services that a particular ecological site can 

support and management alternatives for achieving land management; similar to the ecological type 

used by USDA Forest Service and the old term used by the NRCS, Range Site Description.

Ecological type—a category of land with a distinctive (i.e., mappable) combination of landscape elements: 

climate, geology, geomorphology, soils, and potential natural vegetation. Ecological types differ from 

each other in their ability to produce vegetation and respond to management and natural disturbances. 

Major Land Resource Areas/MLRAs—geographic area, usually several thousand acres in extent, that is 

characterized by a particular pattern of soils, climate, water resources, land uses, and type of farming.

Phase (community)—community phases interact with the environment to produce a characteristic 

composition of plant species, functional and structural groups, soil functions, and range of variability. 

Phases may not progress directly to the most resilient community phase without passing through an 

intermediate phase. 

Potential vegetation—potential vegetation of an ecological site, as described in an ESD, is a function of 

ecological site characteristics (climate, topography, and soils), attributes and processes (soil moisturetemperature regime, soil processes, and vegetation dynamics), and disturbance history

Reference state—historic or potential plant community including seral (successional) stages; based on 

conditions believed to be present before widespread alterations by Euro-Americans.

Resilience—capacity of an ecosystem to regain its fundamental structure, processes and functioning when 

altered by stresses like increased CO2 , nitrogen deposition, and drought and to disturbances like land 

development and fire.

Resistance—capacity of an ecosystem to retain its fundamental structure, processes and functioning (or 

remain largely unchanged) despite stresses, disturbances or invasive species.

Resistance to invasion—abiotic and biotic attributes and ecological processes of an ecosystem that limit 

the population growth of an invading species.

Appendix 9. Definitions of terms used in this field guide. For soil 

terms see Appendix 4. 
66 USDA Forest Service RMRS-GTR-322. 2014

Phases of woodland succession

Characteristics

(post-settlement stands)

Phase I

(early)

Phase II

(mid)

Phase III

(late)

Tree canopy

% of maximum potential 

cover

Open, actively expanding

<1/3 max potential 

Open, actively expanding

1/3 to 2/3 max potential

Expansion nearly stabilized

>2/3 max potential

Leader growth

dominant trees, cm/yr

Terminal > 10

lateral > 10

Terminal >10

lateral 5 to >10

Terminal >10

lateral <5

Crown lift*

dominant trees

Absent Absent Lower limbs dying or dead where 

tree canopy >40%

Tree recruitment Active Active Limited to absent

Potential berry production Low Moderate to high Low to near absent

Leader growth

(understory trees, cm/yr)

Terminal >10

lateral >8

Terminal 5 to >10

lateral 2 to >8

Terminal <5

lateral <2

Restoration pathways—restoration pathways describe the environmental conditions and management 

practices that are required to recover a state that has undergone a transition. 

State—a suite of plant community successional phases ocurring on similar soils that interact with the 

environment to produce resistant functional and structural attributes with a characteristic range of 

variability that are maintained through autogenic repair mechanisms.

Treatment area—an area that is being considered for some form of vegetation manipulation (prescribed 

fire or mechanical treatments) to increase resilience and/or resistance or that has experienced a 

wildfire. The treatment area is often composed of different ecological sites that may have different 

resilience to disturbance and resistance to invasives (a result of varying elevation, topography, soils, 

and disturbance history). It is helpful to place these sites into general groups based on soil moisture/

temperature regime and current vegetation.

Woodland phase I, II, III—phase I: trees are present but shrubs and herbs are the dominant vegetation 

influencing ecological processes on the site; phase II: trees are codominant with shrubs and herbs and 

all three vegetation layers influence ecological processes; phase III: trees are the dominant vegetation 

on the site and the primary plant layer influencing ecological processes on the site (from Miller and 

others 2005). Phases can be calculated using % cover (from Roundy and others 2014).

 Phase I = total tree / total tree + shrub + perennial grass = < 0.33 (tree biomass <1/3)

 Phase II = total tree / total tree + shrub + perennial grass = 0.34-0.65 (tree biomass 1/3 to 2/3)

 Phase III = total tree / total tree + shrub + perennial grass = > 0.66 (tree biomass > 2/3)
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