INVENTORY AND MONITORING

Technical Reference 1734–7

Ecological Site Inventory

December 2001

U.S. Department of the Interior • Bureau of Land Management
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INVENTORY AND MONITORING

Technical Reference 1734–7

Ecological Site Inventory

December 2001

By:

Edward F. Habich

Rangeland Management Specialist

Bureau of Land Management

National Science and Technology Center

Denver, Colorado

U.S. Department of the Interior • Bureau of Land Management
“An ecological site is a distinctive kind of land with specific

physical characteristics that differs from others kinds of land in its

ability to produce a distinctive kind and amount of vegetation.”

–National Range and Pasture Handbook

Suggested citation:

Habich, E.F. 2001. Ecological site inventory, Technical reference 1734-7. Bureau of Land Management.

Denver, Colorado. BLM/ST/ST-01/003+1734. 112 pp.
S

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Preface

i

Preface

SINCE DECEMBER 1982, ecological site

inventory (ESI) has been the Bureau of Land

Management’s (BLM) standard vegetation inventory technique. The ecological site inventory

method involves the use of soils information to

map ecological sites and plant communities and

the collection of natural resource and vegetation

attributes. The sampling data from each of these

soil-vegetation units, referred to as site write-up

areas (SWAs), become the baseline data for

natural resource management and planning.

The purpose of Technical Reference 1734-7,

Ecological Site Inventory, is to identify the procedures for completing an ecological site inventory

and to describe the technique used by the

Natural Resource Conservation Service (NRCS)

to document and describe ecological sites. These

procedures were derived from the NRCS

Rangeland Ecological Site Inventory procedure

as described in their National Range and Pasture

Handbook. Information was also adapted from

the NRCS National Soils Handbook and BLM

Technical Reference 1737-7, Procedures for

Ecological Site Inventory—With Special Reference to

Riparian-Wetland Sites. Technical Reference 1734-7

replaces previous guidance found in BLM

Manual Handbook 4410-1.

The need for natural resource inventories are

mandated by Congress in Section 201(a) of the

Federal Land Policy and Management Act

(FLPMA) of 1976. Congress reaffirmed this need

in Section 4 of the Public Rangelands

Improvement Act (PRIA) of 1978—in particular,

to develop and maintain an inventory of range

conditions and trends on public rangelands, and

to keep that inventory updated on a regular basis.

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Table of Contents

iii

Table of Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i

Chapter 1 - Inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Inventory Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Inventory Plan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Table 1 - Inventory Plan Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Inventory Plan Reviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Inventory Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Figure 1 - Composition of Inventory Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Team Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Soil Survey Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Vegetation Mapping Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Vegetation Transecting Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Phenological Data Collection Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Natural Resource Specialists on the Inventory Team . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Preparing for Field Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Training and Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Aerial Photographs and Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Aerial Photographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Orthophoto Quads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Topographic and Planimetric Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Administrative Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Other Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Remote Sensing Imagery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

General Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Table 2 - Equipment List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Specialized Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Wildlife Biology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Chapter 2 - Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Soil Map Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Consociation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Association . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Undifferentiated Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Soil Map Unit Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Soil Map Unit Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Detailed Soil Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Soil Survey Mapping for Riparian-Wetland Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Figure 2 - Schematic Representation of Soil Map with Line Segments . . . . . . . . . . . . . . . . . . . .17

Importance of Soil Map Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Chapter 3 - Ecological Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Definition of Ecological Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Succession and Retrogression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

States and Transition Pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Figure 3 - State and Transition Model Diagram for an Ecological Site . . . . . . . . . . . . . . . . . . . .20

Historic Climax Plant Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Naturalized Plant Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Potential Natural Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Historic Climax Plant Community Versus Potential Natural Community . . . . . . . . . . . . . . . .23

Changes in Ecological Site Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Characteristic Vegetation States of an Ecological Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Differentiation Between Ecological Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Revising Ecological Site Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Developing New Ecological Site Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

BLM Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Naming Ecological Sites on Rangeland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Numbering Ecological Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Correlating Ecological Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Ecological Site Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Heading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Ecological Site Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Ecological Site ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Major Land Resource Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Interstate Correlation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Physiographic Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Climatic Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Influencing Water Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Representative Soil Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Ecological Dynamics of the Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Plant Communities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Species List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Plant Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Cover and Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Table 3 - Cover and Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Biological Soil Crust Communities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Total Annual Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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v

Plant Community Growth Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Table 4 - Plant Community Growth Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Ecological Site Interpretations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Animal Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Hydrologic Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Recreational Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Wood Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Other Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Supporting Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Associated Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Similar Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Inventory Data References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

State Correlation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Type Locality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Relationship to Other Established Classification Systems . . . . . . . . . . . . . . . . . . . . . .33

Other References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Ecological Site Documentation and References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Authorship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Site Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Forestland Ecological Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Separating Forested Lands from Rangelands in Areas Where They Interface . . . . . . . . . . . . .34

Chapter 4 - Production Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Aboveground Vegetation Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Total Annual Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Production for Various Kinds of Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Herbaceous Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Woody Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Cacti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Methods of Determining Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Figure 4 - Weight Estimate Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Estimating by Weight Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Double Sampling—Estimating and Harvesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Table 5 - Number of Harvested Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Plot Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

Plot Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

Harvesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Units of Production and Conversion Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Plot Size Conversion Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Table 6 - Conversion Factors for Grams to Pounds per Acre . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Table 7 - Conversion Factors for Grams to Kilograms per Hectare . . . . . . . . . . . . . . . . . . . . . . .42

Mixed Measuring Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
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Adjustment Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Green Weight Adjustment Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Double Sampling Adjustment Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

Air-dry Weight Adjustment Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

Utilization Adjustment Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

Growth Adjustment Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

Reconstructing the Present Plant Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

Ocular Estimation of Production Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

Inventory Level of Intensity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

Production Data for Documenting Rangeland Ecological Sites . . . . . . . . . . . . . . . . . . . . . . . .44

Chapter 5 - Similarity Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

Definition and Purpose of a Similarity Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

Table 8 - Successional Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

Determining Similarity Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

Table 9 - Examples of Similarity Index Determinations on a Loamy Upland 12-16 PZ

Ecological Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Table 10 - Reference Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Determining Similarity Index to the Potential Natural Community . . . . . . . . . . . . . . . . . . . .52

Determining Similarity Index to Other Vegetation States or Desired Plant Community . . . . .52

Chapter 6 - Field Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Minimum Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Sampling Precision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Site Write-up Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Field Inventory Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

Mapping Process With a Completed Soil Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

Mapping Process Without a Completed Soil Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Mapping Ecological Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Present Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Table 11 - Common Standard Vegetation Subtypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Successional Status Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Forest Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Feature Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Water Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Photo Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Table 12 - Photo Scale Minimum Size Delineations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Stratification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Table 13 - Recommended Protocols for Stratification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

Table 14 - Stratum Listing and SWA Listing by Stratum . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

Stratums With One Transect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

Stratums With Multiple Transects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
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Transect Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

SWAs With One Soil-Vegetation Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

Figure 5 - One Soil-Vegetation Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

SWAs With Mixed or Mottled Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

Figure 6 - Mixed or Mottled Soil-Vegetation Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

Other Options for Transect Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

Figure 7a - A Two-Legged Transect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

Figure 7b - A Multi-Legged Transect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

Plot Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

Vegetation Production Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

Chapter 7 - Data Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61

Abbreviations and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73

Appendix 1 - Aerial Photography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75

Appendix 2 - Soil Map Unit Delineations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77

Appendix 3 - Ecological Site Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81

Appendix 4 - Vegetation Production Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97

Appendix 5 - Foliage Denseness Classes Utah Juniper . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99

Appendix 6 - Examples of Weight Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101

Appendix 7 - Percent Air-dry Weight Conversion Table . . . . . . . . . . . . . . . . . . . . . . . . . . .103

Appendix 8 - Vegetation Types and Subtypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105

Appendix 9 - Similarity Index Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107

Appendix 10 - Data Element Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109

A

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Inventory Preparation

ADEQUATE INVENTORY PREPARATION is

essential for all ecological site inventories.

Inventory preparation should be initiated at least

1 year prior to the start of field work; however, 2

years is better and is usually required if memorandums of understanding (MOUs) or other

agreements are necessary for interagency efforts.

Inventory preparation includes developing an

inventory plan, conducting inventory plan

reviews, and putting together the inventory team.

Inventory Plan

Prior to beginning an inventory, an interdisciplinary team develops the inventory plan. The

team sets forth in writing the extent and intensity

of the inventory studies needed. The ecological

site inventory is designed to serve as the basic

inventory of present and potential vegetation on

BLM rangelands for use in all programs that

require information on vegetation. 

The level of intensity for the collection of production data should be documented in the inventory plan, along with a discussion about quality

control of data collection. This is necessary to

ensure accuracy and promote consistency

between crews and inventories.

If a Natural Resources Conservation Service

(NRCS) soil survey or soil survey update is conducted along with an inventory, the plan should

be consistent with the soil survey MOU and

plan of operations according to Section 601.05 of

the National Soils Handbook. (See the section on

soil survey for information on the procedure

needed if a soil survey is completed concurrently

with the ecological site inventory.)

A suggested format for the inventory plan is

shown in Table 1. 

Chapter 1 - Inventory
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Table 1 - Inventory Plan Format

Inventory Plan Elements

Purpose Briefly state the purpose of the inventory in general terms.

Objective(s) Identify the specific objective(s) for the inventory data in relation to

uses or issues.

Description of the inventory Identify the location and boundaries. Describe what it looks like 

area (vegetation diversity, topographic diversity).

Identify information to be Although the minimum standards required for an ESI are production

collected and composition by air-dry weight (ADW) by species, all other

types of resource data can be collected. Data collection should be

tailored to local needs. Inventory protocols can be specifically

designed for certain areas within the inventory. Additional data

needs could include:

- Cover

- Vegetation structure

- Rangeland health

- Soil resource values and condition (soil health)

- Tree information (number by size, class, types of tree damage

and extent)

- Noxious weeds

- Biological soil crust 

Inventory design - Identify the level of detail needed. A higher level of detail may be

required in riparian-wetland or other high value areas.

- Specify map scale. Different scales may be required in mapping

uplands and riparian-wetland areas.

- Specify the minimum size limitation for delineating soil map units

and site write-up areas (SWAs). For example, a soil map unit may

be no smaller than 160 acres (for a general order 3 survey), while

a SWA may be as small as 40 acres.

- Determine whether the inventory will be completed in conjunction

with a soil survey or after the soil survey is complete.

- Determine the time that will be needed to complete the field

work and all compilation work.

Personnel and funding - People and skill levels needed (professional level versus seasonal 

requirements and/or or entry level)

constraints - Personnel assigned to complete the work

- Special needs (helicopter support, equipment)
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Logistics - Aerial photo or remote sensing needs

- Agreements or MOUs

- Transportation (vehicles, helicopter)

- Office space

- Chemical storage space (HCL, pH reagents) 

- Lodging (camps, motels)

- Food or per diem requirements

- Equipment, photos, maps (some procurement may be needed 1

year in advance)

- Contracts

- Administrative support

- Coordination with local officials and notification in the local

newspaper, particularly if helicopters are used

Field measurements and - Minimum standards. Production and composition by species, by

procedures SWA, and by ecological site are required. 

- Number and size of plots

- Other data collection methods to be used (Daubenmire, step

point, line intercept, point frame)

- Handbooks and other written guidance

- Data collection (forms, field data recorders)

Compilation procedures - Maps

- Cartographic requirements

- Geographic Information System (GIS) support

- Data storage. Method of tabular data input into the Inventory

Data System (IDS) (local entry into Bureau database)

- Types of reports to be generated and for whom

Reporting and quality control - Training

(inventory reviews and results) - Sampling and harvesting protocols

requirements - Personnel supervision in the field

- Frequency of progress reports (weekly, monthly)

- Who is responsible and when progress and final reports are due

Approval Process - Who the responsible individuals are

- When

- What the administrative levels are

File Maintenance Identify where the field worksheets, maps, and reports will be stored

and plans for computerizing the data. Data must be entered in the

Bureau’s vegetation database. To determine how it will be entered,

contact the National Science and Technology Center (NSTC) in Denver.
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Inventory Plan Reviews 

The inventory plan needs to be reviewed annually

if the inventory takes longer than 1 year to complete. All changes should be documented. The

inventory plan should set forth when and how

reviews will be conducted. The inventory team

should conduct the reviews. Objectives should

be reviewed to ensure adequate quality and

quantity of inventory progress and to identify

problems that need management attention.

Inventory Team

The inventory team generally consists of a team

lead, a soil survey team, a vegetation mapping

team, a vegetation transecting team, and a

phenological data collection team. A soil survey

team may not be necessary if the survey is

already done. Also, if specified in the inventory

plan, the soil survey and vegetation mapping

teams may be combined into a single team to

complete the mapping of the inventory area.

Figure 1, Composition of Inventory Team, is

only a recommendation. Composition of the

actual teams will be decided by each individual

field office.

Inventory team members must be selected carefully. The combined knowledge, experience, education, and training of each member is extremely

important. All specialists on the inventory team

will need to work closely together throughout

the inventory.

Figure 1 - Composition of Inventory Team

Ecological Site Inventory Team Organization

Soil Survey

Team

Vegetation

Mapping

Team

Vegetation

Transecting

Team

Phenological Data

Collection Team

Team

Lead
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Team Lead

The team lead should be a BLM permanent

employee with supervisory experience. Leads

should be selected for their knowledge, experience, competence, and good judgment. They

should be knowledgeable and experienced in the

objectives and procedures of ecological site

inventories and acquainted with the Bureau’s

interrelated programs. They are responsible for

organizing and directing the inventory, coordinating field data collection, assigning work,

keeping equipment in good operating order,

administrative support (time sheets, leave

approval, employee evaluations, travel, training)

and reporting the progress of the inventory.

Soil Survey Team

The soil survey team is needed only if a soil survey has not been completed or if the existing

survey needs further refinement. The team may

include employees from BLM, NRCS, combined

BLM-NRCS, or contract personnel.

Vegetation Mapping Team

The vegetation mapping team usually works in

close contact with the soil survey team and is

responsible for the delineation of ecological sites,

successional status, and present vegetation communities. Team members should include an

experienced vegetation management specialist

(e.g., rangeland management specialist, forester,

ecologist, botanist), a soil scientist, and a wildlife

biologist. If riparian-wetland sites are involved in

the inventory, a hydrologist is critical, at least

during the planning, soil survey, and vegetation

mapping phases. These specialists must be

familiar with the soils and plant and animal

communities of the inventory area. 

Vegetation Transecting Team

The vegetation transecting team is usually

comprised of rangeland management specialists,

biologists, botanists, and foresters. A knowledge

of the plants in the inventory area is required,

along with a good plant taxonomy background.

Botany expertise may be required full or part

time. For riparian-wetland inventory updates, at

least one vegetation specialist with experience in

wetland ecology and wetland plant taxonomy is

needed.

Phenological Data Collection Team

It may be desirable to assign the responsibility of

collecting data for phenological adjustment factors to one or two individuals. This will ensure

accurate data collection in a timely manner for

this important phase of the inventory. This team

may also collect samples for air-dry weight

(ADW) conversion data.

Natural Resource Specialists on the

Inventory Team

The following natural resource specialists can

provide the necessary experience and expertise

as part of the individual teams that form the

main inventory team.

Soil Scientist

The soil scientist is responsible for mapping

ecological sites and developing soil map units.

Vegetation Management Specialist

The vegetation management specialist is

responsible for mapping vegetation communities and administrative boundaries; collecting

vegetation and related resource data (e.g.,

production, cover, rangeland health, structure);

and assisting the soil scientist in mapping

ecological sites and developing soil map units. 

The vegetation management specialist can be

a botanist, biologist, rangeland management

specialist, forester, or anyone proficient in

identifying vegetation species. This expertise is
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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usually involved to some degree on all phases

of the inventory (i.e., vegetation mapping, soil

survey, transecting, and phenology) including

inventory plan preparation.

Wildlife Biologist

The wildlife biologist is responsible for ensuring that wildlife issues and concerns are considered in the mapping of ecological sites and

vegetation communities. This includes noting

special habitat features on aerial photos.

Features to be mapped will have been determined in the pre- planning analysis and inventory plan, which will identify the areas to be

investigated in detail after the inventory is

complete.

Input from a wildlife biologist is recommended

throughout ecological site inventories and soil

surveys. Although not involved during all the

field mapping, the wildlife biologist needs to

have direct input at critical times, which

include the initial planning phase and area base

map preparation; map unit design to ensure

that wildlife habitat vegetation components

are recognized and wildlife interpretation

needs are met; ecological site description

interpretation development and revision; and

development of applicable soil-wildlife-habitat

interpretations. Because of the extremely high

wildlife values associated with riparian-wetland

areas, the wildlife biologist’s participation in

field mapping is critical and participation in

riparian-wetland ecological site inventories and

updates is required. In addition, the wildlife

biologist provides assistance to other members

of the inventory team (e.g., hydrologist) in

completing the field work for developing ecological site descriptions, and is also involved in

inventory plan preparations.

Hydrologist

A hydrologist is an integral part of the inventory team relative to riparian-wetland sites. The

hydrologist is responsible for the description of

water features associated with riparian-wetland

map units and ecological sites. Hydrologic

input for progressive soil surveys and ecological

site inventories is critical during the planning

phase and in map unit design to ensure accurate watershed hydrologic interpretations. The

hydrologist’s input in mapping, describing, and

updating riparian-wetland ecological sites is

required.

The hydrologist works with the soil scientist

and vegetation management specialist to establish interrelationships and ecological responses

to hydrologic events and changes over time

and space attributable to stream dynamics or

other surface and near-surface water fluctuations.

Other Resource Specialists

Input from other natural resource specialists

and managers, other than those mentioned previously, should be actively sought to identify

specific needs whenever necessary. Their input

is especially valuable during the inventory

planning phase and again in the development

of site and soil interpretations. In addition,

assistance from recreation specialists, geologists,

geomorphologists, fire managers, and other

natural resource specialists are often helpful

throughout the inventory and site description

processes depending on the complexity and

resource values associated with individual

areas.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Preparing for Field Operations

The team lead formulates a plan of operation,

assembles materials and equipment, makes

necessary arrangements, and coordinates with

appropriate field office staff. The lead is responsible for ensuring that all forms, maps, photos,

and other equipment and supplies necessary for

conducting the inventory are available.

Training and Orientation

The training and orientation of the inventory

team is the responsibility of the team lead. The

lead is responsible for assessing specific training

needs. This includes scheduling and preparing

training in procedures (e.g., mapping units, data

collection, plant identification, aerial photo interpretation). It also includes orientation to the geographical inventory area and rangeland users.

It is particularly important that the inventory

team be well trained on measurement techniques. The inventory team should have a basic

understanding of the kinds and amount of data

needed and the intended uses of the data.

The need for training in specific sampling techniques for each discipline represented in an ecological site inventory will vary greatly depending

on individual background and expertise. 

The following are recommended courses:

• Inventory and Monitoring of Plant Populations

(BLM National Training Center (NTC) Course

1730-05). Presents information on inventory,

monitoring, analysis, and evaluation techniques for vegetation and plant populations.

• The Ecological Site Concept (BLM NTC

Course 4000-ST-2, self-study course and

video). Provides basic instruction on soil map

units, ecological site concepts, and SWA mapping criteria.

• Coordinated Riparian Area Management (BLM

NTC Course 1737-1). Provides an introduction

to riparian-wetland ecological site concepts, as

well as substantial information on BLM riparian-wetland policies, values, and management

concepts.

• Riparian-Wetland Ecological Site Classification

(BLM NTC Course 1737-4). Advanced course

for mapping and describing riparian-wetland

sites.

• GIS - Geodata for Resource Specialists (BLM

NTC Course 1730-11). Provides a basic understanding and hands-on experience in the concepts, use, and application of GIS.

• Basic Aerial Phot Interpretation (BLM NTC

Course 9160-1). Provides students with the

background and ability to interpret and use

various kinds of aerial photography.

• Soils - Basic Soil Survey: Field and Laboratory

(NRCS National Employee Development

Center (NEDC), Fort Worth). Designed to provide new soil scientists and other specialists an

opportunity to experience what it takes to

complete a soil survey. Output potential of soil

interpretations and use of field and laboratory

methods and data analysis in soil survey are

also discussed.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Additional courses recommended for specific

disciplines include:

• ECS - Range Plant Ecology (NRCS NEDC, Fort

Worth). Advanced course that provides information on the ecological interaction of range

vegetation.

• RES CONS - Saline and Sodic Soils (NRCS

NEDC, Fort Worth). Provides a background

and hands-on experience in understanding

chemical relationships, testing and analyzing

data, recognizing problems, and recommending

management solutions.

• Soils - Soil Correlation (NRCS NEDC, Fort

Worth). Advanced course for soil scientists

provides insight and techniques to apply soil

classification, soil correlation procedure, geomorphic relationships, soil survey area handbook development, and laboratory data analysis

and sampling procedures.

• Soils - Soil Lab Data Use (NRCS NEDC, Fort

Worth). Advanced course for soil scientists

provides insight and techniques for using laboratory data in soil classification and plant

relationships.

• Soils - National Soil Information System

(NASIS) (NRCS). Advanced course for soil scientists familiarizes students with NASIS structure, spreadsheet organization, and how to

populate NASIS data fields.

Aerial Photographs and Maps

Aerial photographs and maps are important tools

in the inventory process. They help identify

locations of natural landscape and special features

and assist in mapping soils, vegetation communities, and special habitat features.

Aerial Photographs

It is essential to have a complete set of aerial

photographs for inventory purposes. These

should be acquired well in advance of the inventory. To facilitate the inventory, more recent (less

than 10 years old) photos are the most desirable.

Natural color or color-infrared photography is

best for mapping vegetation, and a scale of

1:24,000 is best suited for ease of transferring the

information to orthophoto quads or topographic

maps. The aerial photos or orthophoto quads are

used for field mapping and this information is

then transferred to the map base. Aerial photos

are helpful in seeing greater detail, but orthophotos

are better for mapping. Refer to Appendix 1 for

details on acquiring aerial photos.

Orthophoto Quads

Orthophoto quads are distortion-free image

maps at 1:24,000 scale. They are excellent tools

for mapping data in the field or from aerial

photography. They can also be scanned and

georeferenced for inclusion in GIS. With an

ortho image as a backdrop, the user can digitize

the inventory units, display global positioning

system (GPS) data, or analyze other data layers.

Also available in most areas are Digital Ortho

Quarter Quads (DOQQ), which have replaced

paper and film orthophotos and are GIS-ready

images. Contact your State Office GIS coordinator

about availability.

Topographic and Planimetric Maps

Use topographic and planimetric maps or any

high-quality maps that accurately show the

relative position and nature of the inventory

area features. U.S. Geological Survey (USGS)

topographic quadrangles at 1:24,000 scale are the
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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most useable and available. They, too, come in

digital format for GIS and are called USGS

Digital Raster Graphics (DRG).

Administrative Maps

Administrative maps include information such as

management units or grazing allotment boundaries, range improvements, timber harvests, fish

and wildlife habitat, and land status. They are

useful references for team members during the

inventory and can be integrated as data layers for

analysis in GIS if they have been digitized.

Overlays can be made for use with orthophoto

quads as well.

Other Maps

Topographic maps overlaid with geology, precipitation, and land ownership are helpful in

mapping soils and ecological sites.

Remote Sensing Imagery

Remote sensing images may be helpful in mapping landscape features, vegetation communities,

and soils. Remote sensing images can be

obtained at comparable scales to orthophoto

quads providing multispectral information. 

General Equipment

Equipment and tools include items such as photos, maps, references, forms, pens, pencils,

Quadrat frames, and balance scales. Table 2 lists

general equipment common to each discipline. 
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Table 2 - Equipment List

General Equipment Soils Vegetation Wildlife Hydrology

Biology

Inventory plan x x x x

Memorandum of Understanding (MOU) x x x x

Manuals and handbooks 

(see specific lists under Soil, etc.) x x x x

Forms x x x x

Field notebook x x x x

Existing site descriptions common to the

inventory area x x x x

Plant ID references x x x

List of plant names and symbols found

in the State x x x

Geomorphology reports for the area

and related scientific papers x

Plat or land status maps x x x x

Abney level or clinometer x x x

Stereoscope (mirror and pocket) x x

Camera x x x x

Pens and pencils x x x x

Compass (magnetic) x x

Quadrat frames x

Pin flags x

Paper bags x

Balance scales x

Clippers and grass sheers x

Rubber bands x

Auger or probe (hand and/or power) x x x

Shovel (standard) and tile spade x x x

Tape measure (metric and English) x x x x

Computer x x x x

Vehicle and aircraft x x x x

First aid kit x x x x
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Specialized Equipment

The following information lists additional equipment and references specific to each discipline.

Soils

Specific soils needs include, but are not limited

to:

• Manuals and handbooks on procedural guidance

and other references

- NRCS National Soil Survey Handbook

(430-VI-NSSH, 1996)

- Soil Survey Manual (Agriculture Handbook

No. 18, Oct 1983)

- Soil Taxonomy (2nd edition Agriculture

Handbook No. 436 and recent amendments)

- SMSS Keys to Soil Taxonomy (8th Edition,

1998)

- NRCS National Range and Pasture

Handbook (NRPH)

- NRCS National Forestry Manual (NFM)

- NRCS National Biology Manual (NBM)

- NRCS National Cartographic Manual (NCM)

- NRCS Field Handbook for Describing and

Sampling Soils

- USDA-NRCS Soil Series of the United States

(www.statlab.iastate.edu/soils)

- State Hydric Soil List

- For other suggested technical references, see

Section 602-4 of the National Soils

Handbook (NSH). 

• Forms 

- NRCS Field Indicators of Hydric Soils in the

United States (Version 4.0, March 1998)

- Map Unit Transect forms commonly used in

the State NRCS-SOI-232 Pedon Description

or as revised by the State

- NRCS-SOI-232F Soil Description or other

like forms commonly used in field note taking

- Access to the soil survey database software

for data entry into NASIS forms and retrieval

• Field Soil Survey Database (FSSD) for transect

management, pedon management, map unit

records (NASIS), soils database software

• Pedon description program software

• Equipment

Altimeter

Backhoe (mounted on 1-ton truck)

Color charts (Munsell)

Digging bar

Electric conductivity meter

Geology pick

Global positions system unit

Hand lens

Hydrochloric acid (10% solution) 

Knife

Light table

Map board

pH kit (chemical)

pH meter

Sieve set

Soil analysis (portable field laboratory)

Soil sample bags and boxes

Soil hand auger

Soil test kit (chemical)

Soil thermometer

Spot plate

Water bottles

Vegetation

Specific vegetation needs include, but are not

limited to:

• Manuals and handbooks on procedural guidance

and other references

- NRCS National Range and Pasture

Handbook (NRPH)
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- BLM Manual 4400 Rangeland Inventory,

Monitoring, and Evaluation

- BLM Manual 1737-7 Procedures for

Ecological Site Inventory–With Special

Reference to Riparian-Wetland Sites

- National List of Plant Species That Occur in

Wetlands (USFWS)

- Soil-site correlation legend

- Soil map unit descriptions

• Forms

- Vegetation Production Worksheet (Appendix 4)

- NRCS Range 417 or equivalent form

• IDSU (Inventory Data System Utilities) computer program and/or access to IDS at NSTC

• Equipment 

- Rope (plots 96 ft2

, 0.01 acre, .01 acre) 

- Planimeters (if acreages are to be compiled

by field crews)

Wildlife Biology

Specific wildlife biology needs include, but are

not limited to:

• Manuals and handbooks on procedural guidance

and other references 

- BLM Manual 6602, Integrated Habitat

Inventory and Classification System (IHICS)

- Reference guides for the identification of

birds, mammals, and reptiles

• Forms

- Animal Species Occurrence 6602-1

- Special Habitat Features 6602-2

- Resource Field Data Sheets 6602-3

• Computer software and documentation

- Integrated Habitat Inventory and

Classification System (IHICS)

- Special Status Species Tracking (SSST)

- Species Tracking System (STS)

• Equipment

- Field glass

- Magnifying glass

Hydrology

Specific hydrology needs include, but are not

limited to:

• Manuals and handbooks on procedural guidance

and other references

- Stream Classification Reference (Rosgen,

unpublished)

- Water Resources Council Bulletin #17B of

the Hydrology Committee, “Guidelines for

Determining Floodflow Frequency”

- USGS Techniques of Water-Resource

Investigations Reports: 

Book 3, Chapter A1: General field and

office procedures for indirect discharge

measurements

Book 3, Chapter A2: Measurement of peak

discharge by the slope-area method

Book 3, Chapter A8: Discharge measurement at gaging stations

Book 4, Chapter A2: Frequency curves

Book 4, Chapter B1: Low-flow investigations

- Reference guide for estimating Manning's

roughness coefficient

- Reference guides for water-quality field

techniques

• Computer Software and Documentation

- Statistical software, with documentation,

capable of performing frequency analysis

using a log-Pearson Type III frequency

distribution
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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- Open-channel flow software, with documentation, capable of analyzing channel crosssection data, using normal depth and/or standard step calculations to produce relationships between discharge and other hydraulic

parameters

• Equipment

- Surveying equipment

Level, rod, tripod, and survey notebook

- Discharge measuring equipment

Top-setting wading rod

Current meter (Marsh-McBirney or

vertical-axis current meter)

Headset and stopwatch (if using verticalaxis current meter)

Clipboard

USGS discharge measurement forms

- Well points

- Water quality sampling equipment 

Thermometer

Conductivity meter and calibration standards

pH meter and calibration standards

Bottles, labels, and preservatives for water

samples

Coolers with ice for sample transport to

laboratory

Field forms

Sampling equipment for special situations

Depth-integrating sampler (e.g., DH-48),

treated for trace elements, for integrated

cross-section sampling

Bedload or bed-material sampling

equipment

Submersible, peristaltic, or other pump

for shallow ground-water sampling

Field filtration equipment for sampling

dissolved chemical constituents, as

opposed to sampling for total chemistry

S

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 2 – Soils

15

Chapter 2 - Soils

Soil Map Unit

SOIL SURVEY INFORMATION IS IMPORTANT

in mapping ecological sites and vegetation communities. One major feature of a soil survey is

the soil map unit–a group of soil areas or miscellaneous areas delineated in a soil survey. Small

areas of similar and dissimilar soils are classified

as inclusions. Inclusions are discussed in the soil

survey map unit description, but are not mapped

because they are either too small to be delineated

at the scale of mapping or their interpretations

are similar to the dominant soil.

There are four kinds of soil map units: consociation, complex, association, and undifferentiated

group. (See the National Soils Handbook (NSH),

pages 627-10 and 11). The consociation map unit

is the most easily understood level of mapping

because only one ecological site is delineated,

although mapping at such a fine detail level may

not be practical due to minimum size delineations.

Consociation

A consociation is a map unit where the dominant

single soil taxon or miscellaneous area makes up

at least 50 percent of the area.

In a consociation, the similar soils or miscellaneous

areas (soils or miscellaneous areas so similar to

the dominant component that major interpretations do not significantly differ) make up less

than 50 percent of the unit. 

The total amount of dissimilar inclusions (soils

whose interpretations differ from the dominant

soil) generally does not exceed about 15 percent

if the minor components are limiting (soils

whose interpretations limit the use of the soil

more than the dominant soil) and 25 percent if

they are nonlimiting.

Complex

A complex is a collection of two or more dissimilar kinds of soils or miscellaneous areas in a

regular repeating pattern so intricate that they

cannot be delineated separately due to the scale

of mapping selected.

A complex consists of two or more of the following: different soils series, and/or different

phases of soils series, and/or miscellaneous areas

that occur in regular patterns like rock outcrops.

The total amount of dissimilar inclusions (soils

whose interpretations differ from the dominant

soil) generally does not exceed about 15 percent

if the minor components are limiting (soils

whose interpretations limit the use of the soil

more than the dominant soil) and 25 percent if

they are nonlimiting.

Association

An association is similar to a complex, but differs

because the major soil components or miscellaneous areas occur in repeatable patterns and

could have been broken out into separate soil

map units at the scale of mapping but were not.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 2 – Soils

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Soil association maps for low intensity land use

management are more efficient and cost effective

than more detailed mapping without detracting

from the utility of the soil survey. It is more efficient to group and interpret several soils into one

map unit rather than delineate separate map

units.

The information about individual soil series are

not lost, since their percentages and positions on

the landscape are identified in the soil map unit

description.

The total amount of dissimilar inclusions (soils

whose interpretations differ from the dominant

soil) generally does not exceed about 15 percent

if the minor components are limiting (soils

whose interpretations limit the use of the soil

more than the dominant soil) and 25 percent if

they are nonlimiting.

Undifferentiated Group

Undifferentiated soil groups consist of two or

more taxon components that are not consistently

associated geographically and therefore do not

always occur together in the same map unit.

These taxa are included in the same named map

unit because use and management of the soils

are the same or are very similar for common uses.

Every delineation in an undifferentiated group

has at least one of the major components and

may have all the components.

The same principles regarding the proportion of

minor components that apply to consociations

also apply to undifferentiated groups

Soil Map Unit Development

Soil map units are developed based on broad

landscape features. These landscape features are

further broken down into characteristic landforms and geomorphic components, such as

hills, side slopes, toe slopes, floodplains, and

depressions. The kinds of areas associated with

these segments are then identified. Often, distinct vegetation patterns occur along these same

landform and geomorphic surfaces. Generally,

soil map units represent soil components that are

repeated on the landscape.

Soil Map Unit Descriptions

Soil map unit descriptions characterize the map

unit as it is identified and delineated during the

soil mapping process. The contents of a map unit

description will provide information to the user

detailing the setting for each dominant soil component. A brief soil profile description is given

that details distinctive surface features, vegetation relationships, and soil properties that affect

use and management. All dissimilar soil inclusions are identified and their differences in landscape setting and soil profile characteristics are

noted in the description. From these descriptions,

the user should be able to determine the patterns

and percent of occurrence of each component

soil and soil inclusion within the map unit and

their position on the landscape.

Detailed Soil Maps

Base maps of soil surveys are primarily of

two kinds: 

• Rectified photo base maps (high-altitude

photography)
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 2 – Soils

17

• Orthophoto base maps (high-altitude photography

with the displacement of images removed).

Soil map units are delineated on the base map to

provide location and spatial relationships of soils

for subsequent analysis. A map unit symbol can

either be numeric, alphabetic, or a combination

of both (NSH, page 627-7). It consists of no more

than five elements (characters), including digits,

letters, and hyphens that identify the delineation.

The best way to assign map unit symbols is to

sequentially number them and add alpha characters to describe the slope range of the map unit.

The symbol also provides the reference to a map

unit description and associated information. It’s

possible that field map unit symbols could

change at final correlation prior to the publication

of the soil survey.

Soil Survey Mapping for RiparianWetland Areas

Most published soil survey maps, especially at

the 1:24,000 scale are not detailed enough to

delineate riparian-wetland areas, most streams,

seeps, springs, potholes, and other small wet

areas. This may necessitate delineating soil map

units on a larger scale photo. 

One alternative, where GIS capability is available,

is to photographically or digitally enlarge an

orthophoto quad base map to scales between

1:6,000 and 1:12,000 (Batson et al., 1987), delineate and identify the riparian-wetland map units,

and then digitize the areas of the base maps. It is

feasible to map riparian-wetland areas at a photo

scale of 1:2,400 and perform a map transfer to

1:6,000 scale (a reduction of 2.5 times) if that

amount of detail is needed. Riparian- wetland map

unit delineations using this method would be quite

small, but data entry into GIS would be possible.

A second alternative is to simply designate line

segments on a scale of 1:24,000 to represent

stream segments as a map unit and spot symbol

map units for other kinds of riparian-wetland

areas. When either line-break to line-break or

dot-to-dot line segments and ad hoc or dot spot

symbols are used, the average width of stream

segments or the average area of spot symbols will

have to be described in the map unit description.

This method is used with or without GIS capability and soil survey area base maps are needed

for reports. See Appendix 2, Soil Map Unit

Delineations, for more details on using these

techniques. Figure 2 is a schematic representation

of a soil map that includes line segments. Each

area with a symbol represents a soil map unit.

676 1580

1490

174

175

681

585

173

174

123

123

123

252

251

252

1230

1230

1230

1580

Figure 2 - Schematic Representation of Soil

Map with Line Segments. Each area with a

symbol represents a soil map unit.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 2 – Soils

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Importance of Soil Map Units

The soil map unit provides the spatial relationship between soils or groups of soils and landscapes. The map unit also provides the link

between the location of named soil taxa and tabular information on specific soil properties and

interpretations for use and management.

In addition, soil map unit delineations provide

the initial spatial relationship between ecological

sites, which are correlated to the soil components of a map unit. Because of the relationship

between landscape patterns, soils, and ecological

sites, soil maps are an excellent base for other

resource delineations or interpretive maps, such

as wildlife habitat, recreational areas, watershed

conditions, livestock utilization, and many others.
R

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

19

Definition of Ecological Site

RANGELAND LANDSCAPES ARE DIVIDED

into ecological sites for the purposes of inventory,

evaluation, and management. An ecological site

is a distinctive kind of land with specific physical

characteristics that differs from other kinds of

land in its ability to produce a distinctive kind and

amount of vegetation. It is the product of all the

environmental factors responsible for its development, and it has a set of key characteristics

(soils, hydrology, and vegetation) that are included

in the ecological site description. Development

of the soils, hydrology, and vegetation are all

interrelated. Each is influenced by the other and

influences the development of the others.

An ecological site has characteristic soils that

have developed over time throughout the soil

development process. The factors of soil development are parent material, climate, living

organisms, topography or landscape position,

and time. These factors lead to soil development

or degradation through the processes of loss,

addition, translocation, and transformation. Soils

with like properties produce and support a distinctive kind and amount of vegetation and are

grouped into the same ecological site. 

An ecological site has a characteristic hydrology,

particularly infiltration and runoff, that has

developed over time. The development of the

hydrology is influenced by development of the

soil and plant community. 

An ecological site has evolved a characteristic

kind (cool season, warm season, grassland,

shrub-grass, sedge meadowland) and amount of

vegetation. The plant community on an ecological

site is typified by an association of species that

differs from that of other ecological sites in the

kind and/or proportion of species or in annual

production. These vegetation communities

evolved with a characteristic kind of herbivory

(kinds and numbers of herbivores, seasons of

use, intensity of use) and fire regime. Fire frequency and intensity contributed to the

characteristic plant community of the site.

Succession and Retrogression

Succession is the process of soil and plant

community development on an ecological site.

Retrogression is the change in species composition

away from the historic climax plant community

due to management or severe natural climatic

events. 

Succession occurs over time and is a result of

interactions of climate, soil development, plant

growth, and natural disturbances existing on the

site through time. Primary succession is the formation process that begins on substrates having

never previously supported any vegetation (e.g.,

lava flows, volcanic ash deposits). Secondary

succession occurs on previously formed soil from

which the vegetation has been partially or

completely removed.

Ecological site development associated with

climatic conditions and normal range of disturbances (e.g., occurrence of fire, grazing, unusually

wet periods, flooding) produce a plant community

in dynamic equilibrium with these conditions.

This plant community is referred to as the historic

climax plant community. 

Chapter 3 - Ecological Sites
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

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Vegetation dynamics on an ecological site

includes succession and retrogression. The

pathway of secondary succession is often not

simply a reversal of disturbances responsible for

retrogression and may not follow the same

pathway as primary succession.

States and Transition Pathways

A state and transition model is used to describe

vegetation dynamics and management interactions associated with each ecological site. A

state and transition model provides a method to

organize and communicate complex information

about vegetation response to disturbances (e.g.,

fire, lack of fire, drought, unusually wet periods,

insects, and disease) and management. 

A state is a recognizable, relatively resistant and

resilient complex with attributes that include

characteristic climate, soil resource including soil

biota, and the associated aboveground plant

communities (Figure 3). The soil and vegetation

State A

Community 1

Community 2 Community 3

Threshold

State C

Community 6

Community 7

State D

Community 8

State B

Community 4

Community Pathway

Reversible Portion of Transition

Irreversible Portion of Transition

Vegetation Manipulation Practices Needed to Restore Process

 and Return to Previous State

Represents a Change in Transition Trajectory

Community 5

Figure 3 - State and Transition Model Diagram for an Ecological Site.

(Reproduced from the NRCS National Range and Pasture Handbook, 2001.)
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

21

components are inseparably connected through

ecological processes that interact to produce a

sustained equilibrium that is expressed by a specific suite of plant communities. The primary

ecological processes are water cycle, nutrient

cycle, and the process of energy capture. Each

state has distinctive characteristics, benefits, and

values depending upon the intended use, products,

and environmental effects desired from the site.

Two important attributes of a state are resistance

and resilience. Resistance refers to the capability

of the state to absorb disturbance and stresses

and retain its ecological structure. Resilience

refers to the amount of disturbance or stress a

state can endure and still regain its original function after the disturbances and stresses are

removed.

States are relatively stable and resistant to disturbances up to a threshold point. A threshold is

the boundary between two states, such that one

or more of the ecological processes has been

irreversibly changed. Irreversible implies that

restoration cannot be accomplished through natural events or a simple change in management.

Active restoration (e.g., root plowing, seeding,

chaining, prescribed fire, intensive grazing management) must be accomplished before a return

to a previous state is possible. Additional thresholds may occur along the irreversible portion of a

transition causing a change in the trajectory

toward another state as illustrated in Figure 3.

Once a threshold is crossed, a disequilibrium

among one or more of the primary ecological

processes exists and will be expressed through

changes in the vegetative community and eventually the soil resource. A new stable state is

formed when the system reestablishes equilibrium

among its primary ecological processes.

A transition is the trajectory of system change

between states that will not cease before the

establishment of a new state. Transitions can be

triggered by natural events, management actions,

or both. Some transitions may occur very quickly

and others over a long period of time. Two portions of a transition are recognized: reversible

and irreversible. Prior to crossing a threshold, a

transition is reversible and represents an opportunity to reverse or arrest the change. Vegetation

manipulation practices, and if needed, facilitating

practices, are used to reverse the transition. Once

a threshold is crossed, the transition is irreversible

without significant inputs of management

resources and energy. Significant inputs are associated with accelerating practices, such as brush

management and range planting.

States are not static as they encompass a certain

amount of variation due to climatic events,

management actions, or both. Dynamics within

a state do not represent a state change since a

threshold is not crossed. In order to organize

information for management decisionmaking

purposes, it may be desirable at times to describe

these different expressions of dynamics within

the states. These different vegetative assemblages within states will be referred to as plant

communities and the change between these

communities as community pathways. 

Figure 3 illustrates the different components of a

state and transition model diagram for an ecological site. States are represented by the large

boxes and are bordered by thresholds. The small

boxes represent plant communities with community pathways representing the cause of change

between communities. The entire trajectory

from one state to another state is considered a

transition (i.e., from State A to State B). The
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

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portion of the transition contained within the

boundary of a state is considered reversible with

a minimum of input from management. Once

the transition has crossed the threshold, it is not

reversible without substantial input (vegetation

manipulation practices). The arrow returning to a

previous state (State B to State A) will be utilized

to designate types of practices needed. Additional

thresholds occurring along a transition may

change the trajectory of a transition (from State

C to State D).

The first vegetation state described in an ecological site description is the historic climax plant

community or naturalized plant community

(Community 1 from Figure 3). From this state, a

“road map” to other states has been developed.

Each transition will be identified separately and

described, incorporating as much information

known concerning the causes of change, changes

in ecological processes, and any known probabilities associated with the transitions. Plant communities and community pathways within states

may be described as needed.

Historic Climax Plant Community

The historic climax plant community for an ecological site is the plant community that existed

before European immigration and settlement.

This plant community was best adapted to the

unique combination of environmental factors

associated with the site. The historic climax

plant community was in dynamic equilibrium

with its environment. It is the plant community

that was able to avoid displacement by the suite

of disturbances and disturbance patterns (i.e.,

magnitude and frequency) that naturally

occurred within the area occupied by the site.

Natural disturbances, such as drought, fire,

unusually wet periods, and grazing (e.g., native

fauna and insects) were inherent in the development and maintenance of these plant communities. The effects of these disturbances are part of

the range of characteristics of the site that contribute to that dynamic equilibrium. Fluctuations

in plant community structure and function

caused by the effects of these natural disturbances

establish the boundaries of dynamic equilibrium.

They are accounted for as part of the range of

characteristics for an ecological site. Some sites

may have a small range of variation, while others

have a large range. Plant communities that are

subjected to abnormal disturbances and physical

site deterioration or that are protected from natural influences, such as fire and grazing, for long

periods seldom typify the historic climax plant

community. 

The historic climax plant community of an ecological site is not a precise assemblage of species

for which the proportions are the same from

place to place or from year to year. In all plant

communities, variability is apparent in productivity and occurrence of individual species.

Spatial boundaries of the communities, however,

can be recognized by characteristic patterns of

species composition and community structure.

Naturalized Plant Community

Ecological site descriptions have been developed

for all identified ecological sites. In some parts of

the country, however, the historic climax plant

community has been destroyed, and it is impossible to reconstruct that plant community with

any degree of reliability. In these regions, site

descriptions have been developed using the naturalized plant communities for the site. The use

of this option for ecological site descriptions is

limited to those sites where the historic climax

plant community has been destroyed and cannot
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

23

be reconstructed with any degree of reliability.

The annual grasslands of California are an example

of a naturalized plant community.

Potential Natural Community

A potential natural community (PNC) is defined

as the biotic community that would become

established on an ecological site if all successional

sequences were completed without interference

by people under the present environmental conditions. The term “potential natural community”

was recommended for use by the Range

Inventory Standardization Committee (RISC) in

its 1983 report to replace the term “historic climax

plant community.” The RISC report’s rationale

was that PNC recognizes past influences by

man, including past use and introduced exotic

species of animals or plants. Man’s influence is

excluded from the present onward to eliminate

the complexities of management. The concepts

of climax and PNC both refer to a relatively stable

community resulting from secondary succession

after disturbance. Although man may or may not

have caused the disturbance, succession to climax

or PNC occurs without further perceptible

influences of man’s activity. PNC is the preferred

term because it explicitly recognizes that naturalized exotic species may persist in the final stage

of secondary succession and that succession after

disturbance does not always reestablish the

original vegetation.

Historic Climax Plant Community

Versus Potential Natural

Community

In this document, the term “historic climax plant

community” is used in reference to the official

ecological site description. NRCS still requires

the documentation of a historic climax plant

community in the revision or preparation of new

site descriptions. BLM managers and resource

personal have the option of using a PNC for

evaluation of similarity indices rather than an

historic climax plant community. In order to use

PNC there must be compelling evidence that a

particular species or group of species, not

included in the historic climax plant community,

should be included in more advanced successional

vegetation communities.

Changes in Ecological Site

Potential

Severe physical deterioration of an ecological site

can permanently alter the potential to support

the original plant community. Examples include

permanently lowering the water table, severe

surface drainage caused by gullying, and severe

soil erosion. When the ecological site’s potential

has significantly changed, it is no longer considered the same site. A change to another ecological

site is then recognized, and a new site description

may need to be developed on the basis of its

altered potential.

Some ecological sites have been invaded by or

planted to introduced species. The introduced

species may become well established or naturalized to the site. They may dominate the site, or

they may continue to occupy part of the site

even when secondary succession has restored

the plant community to near historic climax conditions. In these cases of invasion or introduction

of nonnative species, a change in ecological site is

not recognized because the edaphic and climatic

potential for the site has not been altered.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

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Characteristic Vegetation States of

an Ecological Site

Where possible, the historic climax plant

community for each ecological site has been

determined. Where it is not possible to determine the historic climax plant community, the

naturalized plant community will be described.

In addition to the historic climax plant community or naturalized plant community, other plant

communities that comprise the known steady

states of vegetation will be determined and

included in future ecological site descriptions.

The description of each plant community should

have been considered as an approximation subject to modification as additional knowledge

becomes available. 

Characteristics of a plant community obtained

from several sources or sites should have been

used to describe the plant communities. The following factors have been considered in evaluating

plant information:

• Effects of fire or lack of fire

• Impacts of grazing or lack of grazing

• Impacts of rodent concentrations

• Impacts from insects

• Soil erosion or deposition by wind or water

• Drought or unusually wet years

• Variations in hydrology and storm events

• Plant disease

• Introduced plant species

The NRCS’ Ecological Site Information System

(ESIS) can provide useful data in identifying plant

communities. This system can be found on the

World Wide Web at http://plants.usda.gov/esis.

Differentiation Between

Ecological Sites

The following guidelines are used to

differentiate one ecological site from another:

• Significant differences in the species or species

groups that are in the historic climax plant

community, such as the presence (or absence)

of one or more species that make up 10 percent or more of the historic climax plant

community by air-dry weight (ADW)

• Significant differences in the relative proportion of species or species groups in the historic

climax plant community, such as a 20 percent

(absolute) change in composition by ADW

between any two species in the historic climax

plant community

• Significant differences in the total annual production in the historic climax plant community

• Soil factor differences that determine plant

production and composition, the hydrology of

the site, and the functioning of the ecological

processes of the water cycle, nutrient cycles,

and energy flow

Any differences in these guidelines (either singly

or in combination) great enough to indicate a

different use potential or to require different

management, are the basis for establishing or

differentiating a site.

These guidelines are not definitive for site differentiation or combination. The differences between

sites may be finer or broader than the guidelines.

Rationale, and the site features listed in the

respective ecological site descriptions, should

readily and consistently distinguish the differences.
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Differences in kind, proportion, or production of

species are the result of differences in soil, topography, climate, and other environmental factors.

Slight variations in these factors are not criteria

for site differentiation; however, individual environmental factors are frequently associated with

significant differences in historic climax plant

communities. The presence or absence of a

water table within the root zone of highly saline

soil in contrast to a nonsaline soil is dramatically

reflected in plant communities that such soils

support. Marked changes in soil texture, depth,

and topographic position usually result in pronounced differences in plant communities, total

production, or both. Therefore, such contrasting

conditions in the soil characteristics, climate,

topography, and other environmental factors

known to be associated with a specific ecological

site can be used as a means of identifying the

site when the historic climax plant community is

absent.

Generally, one species or group of species dominate a site. Dominant status does not vary from

year to year. Because of their stability in the

historic climax plant community, dominant

species have often been used to distinguish sites

and to differentiate one site from another.

In evaluating the significance of kinds, proportion,

and production of species or species groups that

are dominant in a historic climax plant community, and given different soil characteristics, the

relative proportion of species may indicate

whether one or more ecological sites are involved.

For example, in one area the historic climax plant

community may consist of 60 percent big

bluestem and 10 percent little bluestem, and in

another area it may consist of 60 percent little

bluestem and 10 percent big bluestem. Thus,

two ecological sites are recognized. Even though

the production and species are similar, the

proportion’s difference distinguishes them as

separate sites.

The effect of any single environmental factor can

vary, depending on the influence of other factors.

For example, soil depth is more significant on a

site that receives extra water from runoff or in a

high precipitation zone than on an upland site in

a low precipitation area. An additional 2 inches

of annual rainfall may be highly important in a

section of the country that has an arid climate,

but of minor significance in a humid climate. A

difference in average annual production of 100

pounds per acre, ADW, is of minor importance

on ecological sites capable of producing 2,000

pounds per acre. This difference, however, is

highly significant on sites capable of producing

only 200 to 300 pounds per acre. Similar variations in degree of significance apply to most factors of the environment. Consequently, in the

identification of an ecological site, consideration

was given to its environment as a whole, as well

as to the individual components.

Where changes in soils, aspect, topography, or

moisture conditions are abrupt, ecological site

boundaries are distinct. Boundaries are broader

and less distinct where plant communities

change gradually along broad environmental gradients of relatively uniform soils and topography.

Making distinctions between ecological sites

along a continuum is difficult. Thus, the need for

site differentiation may not be readily apparent

until the cumulative impact of soil and climatic

differences on vegetation is examined over a

broad area.

At times, less frequently occurring plants may

increase on a site or the site may be invaded by

plants not formerly found in the historic climax

plant community. The presence or absence of

these plants may fluctuate greatly because of
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

26

differences in microenvironment, weather

conditions, or human actions. Consequently,

using them for site identification can be misleading, so they should not be used to differentiate

sites. Site differentiation, characterization, and

determination are based on the plant community

that develops along with the soils. A study of

several locations over several years is needed to

differentiate and characterize a site.

Availability and accessibility to domestic livestock

grazing are not factors in ecological site determination and differentiation. Site differentiation is

based on those soil characteristics, response to

disturbance, and environmental factors that have

direct effect on the nature of the historic climax

plant community production.

Revising Ecological Site

Descriptions

Analysis and interpretation of new information

about the soil, vegetation, and other onsite environmental factors may reveal a need to revise or

update ecological site descriptions. Because the

collection of such information through resource

inventories and monitoring is a continuous

process, site descriptions may be reviewed periodically for needed revision. It is especially

important that site descriptions be reviewed

when new data on production or response to

disturbance become available. Documented production data, along with related soil, climate,

and physiographic data, will be the basis of the

site description revisions or new site descriptions.

Developing New Ecological Site

Descriptions

A new ecological site description should be prepared when data analysis or new information

reveals that a different or new ecological site

exists. Generally, enough land area must be identified to be of importance in the management or

study of the site before a new site will be 

developed and described. A new ecological site

may be differentiated from an existing site when

sufficient erosion or other action has occurred to

significantly alter the site's potential.

BLM Procedures

BLM has the capability to develop new site

descriptions and propose revisions to existing

ecological site descriptions. However, each new

site description or proposed change must be prepared using the procedure identified in Chapter 3

of the NRCS National Range and Pasture

Handbook. All new and proposed revisions must

be reviewed and approved by the local and State

NRCS offices. 

Naming Ecological Sites on

Rangeland

Ecological sites have been named to help users

recognize the kinds of rangeland in their locality.

Names of ecological sites are brief and are based

on readily recognized permanent physical features

such as the kinds of soil, climate, topography, or

a combination of these features. Examples of

ecological site names based on these criteria are

Deep Sand, Sandy, Sandy Plains, Limestone Hills,
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Clay Upland, Saline Lowland, Gravely Outwash,

Level Winding Riparian, Pumice Hills, Subirrigated, Wet Meadows, Fresh Marsh, and Sandy

Savanna. Some States have chosen to add the

dominant species commonly found on the site to

the ecological site name. Examples are Alkali

Bottom (Alkali Sacaton), Desert Clay (Shadscale),

and Upland Loam (Basin Big Sagebrush).

Ecological sites having similar soils and topography may exhibit significant differences in their

historic climax plant communities because of

climatic differences. For example, the average

annual precipitation of a clay loam in southern

Arizona ranges from 12 to 16 inches.

Quantitative evaluation indicates that the

amount of vegetation produced in areas where

precipitation is 16 to 19 inches is significantly

more than that produced in areas where precipitation is 12 to 16 inches. Thus, two ecological

sites are recognized and are distinguished by the

inclusion of the precipitation zone (PZ) in the

name of the sites, as in Clay Loam Ecological Site

12-16 PZ and Clay Loam Ecological Site 16-19 PZ.

The limited number of permanent physiographic

features or other features used in naming ecological sites makes repeated use of these terms

inevitable. Deep sands, for example, occur in

areas of widely divergent climate and support

different natural plant communities. The name

Deep Sand is appropriate for each of these areas,

but obviously it is used throughout the country

to designate several ecological sites. Where this

occurs within a land resource area, the applicable

precipitation zone or other differentiating factors

are to be included as part of the name. Sites that

have the same name, but are in different major

land resource areas, are different sites.

Numbering Ecological Sites

The ecological site number for rangelands

consists of five parts:

1. The first character designates whether the site

is a rangeland site (R) or a forest site (F). Since

this identifier is not actually a part of the

number, it is rarely used. 

2. A three-digit number and one-digit letter

representing the Major Land Resource Area

(MLRA)

3. A single letter representing a Major Land

Resource Unit (MLRU)

4. A three-digit site number assigned by the

State

5. A two-digit letter State postal code

If the MLRA has only two numbers, a zero is

inserted in the first space followed by the two

numbers. The first letter (e.g., A, B, C) following

the MLRA number represents the MLRA subdivisions. Where no MLRA subdivisions are identified, an X is used in the fourth space to denote

that there is no MLRA subdivision. The fifth

space is reserved for the MLRU letter for States

that use the MLRU designation. For those States

that do not use the MLRU designation, a Y is

inserted. The next three digits represent the individual ecological site number and are assigned

by the State. The final two letters are the State’s

two-letter postal code. An example of an

ecological site number is: RO41XC313AZ

Ecological sites for MLRAs that extend into

adjoining States would retain the same identification number including the State designation
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

28

for both States. The State postal code attached

would be the State that first described the site. 

Site descriptions will be labeled as “draft” until

the NRCS’s State range conservationist approves

the site description.

Correlating Ecological Sites

Ecological sites should have been correlated

between areas, States, and MLRAs on the basis

of soils, proportion of species, and annual production of the potential plant communities. In

this process, ecological site descriptions are

reviewed to ensure consistency in identifying

and describing the same site across State, area,

and MLRA boundaries. These reviews include

comparing similar sites to determine whether

they are in fact different ecological sites.

Correlation also involves the review of soils

information to ensure the description matches

the soil properties in the individual soil series.

Only one name should have been given to a

single site that occurs in adjacent States within

the same MLRA. 

Ecological Site Description

A description has been prepared for each ecological site (see an example in Appendix 3). The

description identifies the important resources for

the site that are used to identify, evaluate, plan,

develop, manage, and monitor rangelands. The

description includes the following information,

as appropriate:

Heading

All ecological site descriptions will identify the

USDA and Natural Resources Conservation Service.

Ecological Site Name

The full name of the site should appear on each

page of the description.

Ecological Site ID

The site number is a 10-digit number that also

appears on each page of the description.

Major Land Resource Area

Identifies the major land resource area code and

common name.

Interstate Correlation

Lists the States that have correlated the site.

Physiographic Features

Describes the occurrence of the site on the landscape. In reference to the historic climax plant

community, includes information on whether

the site typically generates runoff, receives

runoff from other sites, or receives and generates

runoff. Physiographic features include:

• Landform

• Aspect

• Site elevation
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• Slope

• Water table

• Flooding

• Ponding

• Runoff class

Climatic Features

Climatic features include:

• Frost-free period (length and dates)

• Freeze-free period (length and dates)

• Mean annual precipitation

• Monthly moisture and temperature distribution

• Location of climate stations

Influencing Water Features

Includes information regarding water features

where the plant community is influenced by

water or the water table from a wetland or

stream associated with the site. Water features

include the Cowardin wetland classification

system and Rosgen stream classification system.

Representative Soil Features

The main soil properties associated with the

site are briefly described. This includes:

• Properties that significantly affect plant, soil,

and water relationships, and the site hydrology

• The extent of flow patterns, and the rills and

gullies found in the historic climax plant

community

• The amount and patterns of pedestaling and

terracettes caused by wind or water inherent

to the historic climax plant community

• The size and frequency of wind-scoured areas

• The susceptibility of the site to compaction

• A description of the expected organic layer and

physical and chemical crusts that might be

present

Representative soil features include:

• Parent materials

• Surface texture

• Subsurface texture

• Surface fragments

• Subsurface fragments

• Drainage class

• Permeability class

• Depth

• Electrical conductivity

• Sodium absorption ratio

• Calcium carbonate equivalent

• Soil reaction

• Available water holding capacity

Ecological Dynamics of the Site

The general ecological dynamics of the site are

described. Included are the expected changes

that are likely to occur because of variations in

the weather and the effects this might have on

the dynamics of the site. Included are assumptions

regarding site development (e.g., fire frequency,

native herbivory).

Plant Communities

This section describes:

• Vegetation dynamics of the site

• State and transition model diagram

• Common states that occur on the site and the
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

30

transitions between states. Included are the

plant communities and community pathways

within each state.

• Ground cover and structure

• Annual production

• Growth curves

• Photos of each state or community

The first plant community to be described

should be the interpretative community. This

plant community will be either the historic climax plant community or, where applicable, the

naturalized plant community for the site. 

Other states and plant communities that may

exist on the site are also described. One or more

plant communities for each state will be

described. Included is a narrative describing the

dynamics of each state and plant community and

the causes of community pathway changes. Also

described are the thresholds between states, and

information that will aid in the identification and

evaluation of how the ecological processes of the

site are functioning. 

Information regarding transitions between states

should have been included in the plant community narrative, as well as causes of change and

any known probabilities associated with the

transitions.

Species List

A detailed species list will be included for the

historic climax plant community and each stable

state plant community known to exist on the

site. Each listing should include the major plant

species (i.e., common name and scientific name)

and their normal relative production expressed in

pounds ADW (pounds per acre per year) in the

total plant community. Species should be listed

by life form and group, including pounds per

acre allowable for each group.

Plant Groups

Ecological site descriptions usually list plant

species by groups. Plant groups include: 

• Cool season tall grasses

• Cool season midgrasses

• Warm season tall grasses

• Warm season midgrasses

• Warm season short grasses

• Annual grasses

• Perennial forbs

• Biennial forbs

• Annual forbs

• Succulent forbs

• Leafy forbs

• Shrubs

• Half-shrubs

• Deciduous trees

• Evergreen trees

• Cacti

• Yucca

• Yucca-like plants

Other factors used to identify groups include: 

• Kind of plant

• Structure

• Size

• Rooting structure

• Life cycle

• Production

• Niche occupied

• Photosynthetic pathways

If plant groups are shown, plant groupings will

identify whether individual species within the

group have a production limitation or whether a
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

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single species can account for the entire group

allowable. 

Groups may be subdivided into separate groups

or combined. For instance, two or three groups

of warm season mid-grasses may be described

because of different niches occupied and differences in production, structure, elevation, and climatic adaptations in the area of the site.

Cover and Structure

The following table (Table 3) is an adaptation of

the table on ground cover and structure found in

Appendix 3. Table 3 has been changed to more

clearly illustrate ground cover and canopy cover

layers (structure) for use by BLM.

Ground cover is the percentage of material, other

than bare ground, that protects the soil surface

from being hit directly by a raindrop. This would

include first contact with plant canopy cover,

biological crust, litter, rock fragments, bedrock,

and water.

Canopy cover is the percentage of ground covered

by a vertical projection of the outermost perimeter of the natural spread of foliage of plants.

Structure is the average height and canopy cover

of each layer of vegetation.

Table 3 - Cover and Structure

Ground and Canopy Cover

Structure - Height Above the Ground

Not Applicable 6–12 inches 12–24 inches 24–60 inches 180–240 inches

%ground %canopy %ground %canopy %ground %canopy %ground %canopy %ground %canopy

cover cover cover cover cover cover cover cover cover cover

Trees

Shrubs

Forbs

Grasses

Litter

Cryptogams

Rock

Fragments

Bare Ground
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Biological Soil Crust Communities

Information on biological soil crust communities

(e.g., mosses, lichens, cyanobacteria, algae) usually includes only cover data. However, on tundra sites where current production can be determined on lichens and mosses, production may

be expressed as total live biomass.

Total Annual Production

Total annual production is shown as the median

air-dry production and the fluctuations to be

expected during favorable, normal, and unfavorable years. In areas where examples of the historic climax plant community are not available,

the highest production in plant communities for

which examples are available have been used.

Plant Community Growth Curves

Plant community growth curves are displayed

for each important plant community. Growth

curves indicate the percent of growth by month

(Table 4). This includes:

• Number - This number is used only one time

in each State. The first 2 digits are the State

postal code, and the last 4 digits are consecutive

numbers from 001 to 9999.

• Name - This is a brief descriptive name for

each curve.

If plant community growth curves are not

available, contact the NRCS.

Table 4 - Plant Community Growth Curves

Growth curve number:

Growth curve name:

Growth curve description:

Jan Feb March April May June July Aug. Sept. Oct. Nov. Dec.

Ecological Site Interpretations

This section includes the site interpretations for

the use and management of the site. The information includes: 

Animal Community

This narrative describes the major wildlife

species that occupy or use the site. It will include

any major values or problems associated with

their use of this site and the plant communities

that may occur on it. Special status animal

species, such as threatened and endangered

species, and State or local species of concern are

discussed. General descriptions of the use of this

site by livestock and wild horses and burros

should also be included. Suitability of the site

for grazing by season and by kind and class of
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

33

livestock will be addressed. Included in the discussion is a list of major barriers to wildlife and

livestock use (e.g., water, topography).

Hydrologic Functions

This discussion includes effects on the hydrologic functions from shifts to different plant communities. There should be a description of the

changes in infiltration and runoff characteristics

expected due to changes in plant communities

and soil surface characteristics. Information

about water budgets for each plant community

could be included.

Recreational Uses

Potential recreational uses that the site can support or that may influence the management of

the site should be discussed. Included will be a

list of special concerns that affect the maintenance of the recreational potentials or site conditions that may limit its potential. Also listed are

plant species that have special aesthetic values,

uses, and landscape value.

Wood Products

Indicates use or potential uses of significant

species that may influence the management of

the site.

Other Products

Indicates the use or potential uses of other products produced on the site. These may include

landscape plants, nuts, berries, mushrooms, and

biomass for energy potentials.

Supporting Information

This narrative involves information about the

relationship of this site to other ecological sites.

Includes information regarding documentation

and references used to develop the ecological site

description.

Associated Sites

This is a listing and description of other ecological sites that are commonly located in conjunction with this site.

Similar Sites

Identifies and describes ecological sites that

resemble or can be confused with the site.

Inventory Data References

Includes a listing of sample transects or plots

supporting the site description. 

State Correlation

Includes the states that this site has been correlated with.

Type Locality

Includes the location of a typical example of the

site. Indicates township, range, and section or

longitude and latitude of the specific location. 

Relationship to Other Established

Classification Systems

Includes a description of how this ecological

site description may relate to other established

classification systems.

Other References

Includes other reference information used in site

development or in understanding the ecological

dynamics of the site.

Ecological Site Documentation and

References

Each ecological site description documents the

following information about the preparation of

the original or latest version of the description:
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 3 – Ecological Sites

34

Authorship

The original author’s initials and date. Revision

author's initials and revision date.

Site Approval

Includes signature, title, and date of the State

technical specialist who reviewed and approved

the ecological site description.

Forestland Ecological Sites

Forestland ecological site descriptions normally

characterize the mature forest plant community

that historically occupied the site as well as the

other major plant communities that commonly

occupy the site. An example of a forestland ecological site description can be found in the NRCS

National Forestry Manual, part 537, subpart E,

exhibit 537-14.

Separating Forested Lands from

Rangelands in Areas Where They

Interface

Rangeland and forested land ecological sites are

separated based on the historic kind of vegetation that occupied the site. Forested land ecological sites are assigned and described where this

historic vegetation was dominated by trees.

Rangeland ecological sites are assigned where

overstory tree production was not dominant in

the climax vegetation.
A

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 4 – Production Data

35

Aboveground Vegetation

Production

ALL PRODUCTION AND COMPOSITION data

collected are based on weight measurements.

Weight is the most meaningful expression of the

productivity of a plant community or an individual

species.

Production is determined by measuring the

annual aboveground growth of vegetation. Some

aboveground growth is used by insects and

rodents, or it disappears because of weathering

before production measurements are made.

Therefore, these determinations represent a productivity index. They are valuable for comparing

the production of different rangeland ecological

sites, plant species composition, and similarity

index.

Comprehensive interpretation of plant production and composition requires that data be representative of all species having measurable production. Rangeland and other grazing lands may

be used or have potential for use by livestock

and wildlife, as recreation areas, as a source of

certain wood products, for scenic viewing, and

for other soil and water conservation purposes.

The value of plant species for domestic livestock

often is not the same as that for wildlife, recreation, beautification, and watershed protection.

Furthermore, the principles and concepts of

rangeland ecological site, similarity index, and

other interpretations are based on the total plant

community. Therefore, interpretations of a plant

community are not limited solely to species that

have value for domestic livestock.

The procedures and techniques discussed in this

section relate primarily to rangeland. Most of

them, however, also apply to grazeable forest

and native or naturalized pasture. Changes or

modifications in procedures required for land

other than rangeland are described.

Total Annual Production

The total aboveground production of all plant

species of a plant community during a single

year is total annual production. Total annual

production includes the aboveground parts of all

plants produced during a single growth year,

regardless of accessibility to grazing animals. An

increase in the stem diameter of trees and

shrubs, production from previous years, and

underground growth are excluded.

Production for Various Kinds of

Plants

The Vegetation Production Worksheet

(Appendix 4) can be used to record production

data on individual plots.

Chapter 4 - Production Data
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 4 – Production Data

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Herbaceous Plants

These plants include grasses (except bamboos),

grasslike plants, and forbs. Annual production

includes all aboveground growth of leaves,

stems, inflorescence, and fruits produced in a single year.

Woody Plants

Determining production of trees and large shrubs

by harvesting portions of stands is time consuming and impractical. Research scientists are devising methods for calculating current production of

some species on the basis of measurements of

such factors as crown width or height and basal

area. These data are helpful in estimating the

annual production of trees and large shrubs.

(Appendix 5 provides an example of estimating

annual production on Utah Juniper.)

Deciduous Trees, Shrubs, Half-shrubs, and

Woody Vines

Annual production includes leaves, current twigs,

inflorescence, vine elongation, and fruits produced in a single year.

Evergreen Trees, Shrubs, Half-shrubs, and

Woody Vines

Annual production includes current year leaves

(or needles), current twigs, inflorescence, vine

elongation, and fruits produced in a single year.

Yucca, Agave, Nolina, Sotol, and Saw

Palmetto

Annual production consists of new leaves, the

amount of enlargement of old leaves, and fruiting

stem and fruit produced in a single year. Until

more specific data are available and if

current growth is not readily distinguishable,

consider annual production as 15 percent of the

total green- leaf weight plus the weight of current

fruiting stems and fruit. Adjust this percentage in

years of obviously high or low production.

Cacti

Prickly Pear and Other Pad-forming Cacti 

Annual production consists of pads, fruit, and

spines produced in a single year plus enlargement

of old pads in that year. Until more specific data

are available and if current growth is not readily

distinguishable, consider annual production as 10

percent of the total weight of pads plus current

fruit production. Adjust this percentage for years

of obviously high or low production.

Barrel-type Cactus

Until specific data are available, consider annual

production as 5 percent of the total weight of the

plant, other than fruit, plus the weight of fruit

produced in a single year.

Cholla-type Cactus

Until specific data are available and if current

growth is not readily distinguishable, consider

annual production as 15 percent of the total

weight of photosynthetically active tissue plus

the weight of fruit produced in a single year.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 4 – Production Data

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Methods of Determining

Production

Production of a plant community can be determined by estimating, by harvesting, or by a

combination of estimating and harvesting (double

sampling) depending on the intended use of the

data. 

Some plants are on State lists of threatened or

endangered species, or are otherwise protected

species. Regulations concerning these species

may conflict with the harvesting procedures

described. For example, barrel-type cactus in

some States is a protected species, and harvesting

is not allowed.

The weight of such plants is to be estimated

unless special permission for harvesting can be

obtained. Examiners determining production

should be aware of such plant lists and regulations.

When estimating or harvesting plants, include all

parts of all plants within the plot, and exclude all

portions outside the plot, even though the plants

are rooted within the plot. Include portions of

plants extending into the plot, but rooted outside

the plot (Figure 4).

Exclude

all parts of 

all plants

outside the plot

Include 

all parts of

all plants

within the plot

Figure 4 - Weight Estimate Plots.

(Adapted from Sampling Vegetation

Attributes, Technical Reference 1734-4,

Illustration 23, 1996.)
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 4 – Production Data

38

Estimating by Weight Units

The relationship of weight to volume is not

constant; therefore, production and composition

determinations are based on weight estimates,

not on comparison of relative volumes. The

weight unit method is an efficient means of estimating production and lends itself readily to selftraining. This method is based on the following:

• A weight unit is established for each plant

species occurring on the area being examined.

• A weight unit can consist of part of a plant, an

entire plant, or a group of plants (see Appendix

6, Examples of Weight Units).

• The size and weight of a unit vary according

to the kind of plant. For example, a unit of 5 to

10 grams is suitable for small grass or forb

species. Weight units for large plants may be

several pounds or kilograms.

• If a majority of estimates for a particular

species are in fractions of a weight unit (e.g.,

0.1, 0.5, 0.7), then the size of the weight unit is

probably too high.

• Other considerations include:

- Length, width, thickness, and number of

stems and leaves

- Ratio of leaves to stems

- Growth form and relative compactness of

species

The following procedure can be used to

establish a weight unit for a species:

1. Decide on a weight unit (in pounds or

grams) that is appropriate for the species.

2. Visually select part of a plant, an entire plant,

or a group of plants that will most likely

equal this weight.

3. Harvest and weigh the plant material to

determine actual weight.

4. Repeat this process until the desired weight

unit can be estimated with reasonable accuracy.

5. Maintain proficiency in estimating by periodically harvesting and weighing to check

estimates of production.

The procedure for estimating production and

composition of a single plot is:

1. Estimate species composition by visually

estimating the percent by weight of each

species with the total weight for the entire

plot.

2. Estimate production by counting the weight

units of each species in the plot.

3. Convert weight units for each species to

grams or pounds.

4. Harvest and weigh each species to check

estimates of production.

5. Compute composition on the basis of actual

weights to check composition estimates.

6. Repeat the process until proficiency in estimating is attained.

7. Periodically repeat the process to maintain

proficiency in estimating.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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8. Keep the harvested materials, when necessary, for air-drying and weighing to convert

from field (green) weight to air-dry weight

(ADW).

Double Sampling—Estimating and

Harvesting

The double-sampling method is to be used in

making most production and similarity index

determinations. The procedure is:

1. Select a study area consisting of one soil taxonomic unit. This should be a soil taxonomic

unit that is an important component of a

rangeland ecological site or forestland

ecological site.

2. Select plots at specified intervals along a linear transect. The starting point is randomly

located within the site write-up area (SWA).

3. After plots are selected, estimate and record

the weight of each species in each plot using

the weight-unit method. When estimating or

harvesting, include all parts of all plants

within the plot. Exclude all portions of all

plants outside the vertical projection of the

plot.

4. After weights have been estimated on all

plots, select the plots to be harvested. The

plots selected should include all or most of

the species in the estimated plots. If an

important species occurs on some of the estimated plots, but not on the harvested plots,

it can be clipped individually on one or more

plots. The number of plots harvested depends

on the number estimated. To adequately

correct the estimates, research indicates at

least one plot should be harvested for each

seven estimated. At least 2 plots are to be

harvested if 10 are estimated, and 3 are to be

harvested if 20 are estimated. Table 5 shows

the minimum number of plots to be harvested

based on the number of estimated plots.

Table 5 - Number of Harvested Plots

Number of Minimum Number of

Plots Estimated Harvested Plots

1 - 7 1

8 - 14 2

15 - 21 3

22 - 28 4

29 - 35 5

36 - 42 6

5. Harvest, weigh, and record the weight of

each species in the plots selected for harvesting. Harvest all parts of all plants within the

plot. Exclude all portions of all plants outside

the vertical projection of the plot.

Correct estimated weights by calculating an

adjustment factor. To do this, divide the harvested weight of each species by the estimated

weight for the corresponding species on the

harvested plots. This factor is used to correct

the estimates for that species in each plot. A

factor of more than 1.0 indicates the estimate

is too low. A factor lower than 1.0 indicates

the estimate is too high.

6. After plots are estimated and harvested and

adjustment factors for estimates computed,

air-dry percentages are determined by airdrying the harvested materials or by selecting
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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40

the appropriate factor from an air-dry percentage table (Appendix 7). Values for each

species are then corrected to air-dry pounds

per acre or kilograms per hectare for all plots.

Average weight and percentage composition

can then be computed for the sample area.

Plot Size

Adapt the size and shape of plots to the kind of

plants to be sampled. The area of a plot can be

expressed in square feet, inches and meters, or in

acres.

If vegetation is relatively short, the following

plot sizes work best in determining production:

0.96 ft2 or 41.7 inch circumference

1.92 ft2 or 59 inch circumference

2.40 ft2 or 66 inch circumference

4.80 ft2 or 93.2 inch circumference

9.60 ft2 or 131.8 inch circumference

The listed plots are the most useful when converting grams to pounds per acre. The 9.6 ft2 plot

is generally used in areas where vegetation

density and production are relatively light. The

smaller plots, especially the 0.96 ft2 and 1.92 ft2

plots, are satisfactory in areas of homogeneous,

relatively dense vegetation like that occurring in

meadows. Plots larger than 9.6 ft2 should be used

where vegetation is very sparse and heterogeneous.

If the vegetation consists of trees or large shrubs,

larger plots must be used. If the tree or shrub

population is uniform, a 0.01 acre plot is more

suitable. If vegetation is unevenly spaced, a more

accurate sample can be obtained by using a 0.1

acre plot, 4.356 feet wide and 1,000 feet long.

For statistical analyses, 10 plots of 0.01 acre are

superior to a single 0.1 acre plot. Plots of 0.1 and

0.01 acre are most useful when production

data is collected in pounds because it is a direct

conversion. 

If vegetation is mixed, two sizes of plots generally

are needed. A series of 10 square or rectangular

plots of 0.01 acre and a smaller plot, such as the

9.6-square-foot plot nested in a designated corner of each larger plot, is suitable. The 0.01-acre

plot is used for trees or large shrubs, and the

smaller plot for lower-growing plants. Weights of

the vegetation from both plots are then converted

to pounds per acre. Plots with area expressed in

square meters are used if production is to be

determined in kilograms per hectare.

If the plots are nested, production from both

plots must be recorded in the same units of

measure. For example, a plot 20 meters by 20

meters (or other dimensions that equal 400

meters) can be used for measuring the tree and

shrub vegetation and a 1-meter plot nested in a

designated corner can be used for measuring the

low-growing plants. Determine the production

from both in grams and convert the grams to

kilograms per hectare. Plots of 0.25, 1, 10, 100,

and 400 square meters are commonly used.

Plot Shape

Plots can be circular, square, or rectangular.

However, long-narrow plots are likely to be more

accurate than circular, square, or rectangular

plots (Krebs 1989). Edge effect can result in

significant measurement bias if the plots are too

small (Wiegert 1962). Since aboveground vegetation must be clipped in some plots, circular plots

should be avoided because of the difficulty in

cutting around the perimeter of the circle with

hand shears and the likely measurement bias

that would result.
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Chapter 4 – Production Data

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Harvesting

This method is similar to the double-sampling

method except that all plants in all plots are harvested. The double-sampling procedures for estimating weight by species and the subsequent

correction of estimates do not apply. Conversion

of harvested weight to air-dry pounds per acre or

kilograms per hectare are performed according to

the procedures described for double sampling.

Units of Production and

Conversion Factors

All production data are to be expressed as ADW

in pounds per acre (lb/acre) or in kilograms per

hectare (kg/ha). The field weight must be converted to ADW. This may require drying or the

use of locally developed conversion tables.

Plot Size Conversion Factors

All weights need to be converted to pounds per

acre. The following plot size conversion factors

(CFs) calculate pound per acre or kilograms per

hectare for various weight units (e.g., grams or

pounds) and plot sizes (e.g., 9.6 ft2

, 0.1 acre, 1

m2

, 400 m2). 

The weight of vegetation on plots measured

in square feet or in acres can be estimated and

harvested in grams or in pounds, but weight is

generally expressed in grams. If weights are collected on 10 plots, the total weight is converted

to pounds per acre by using the factor in column

3. If production is collected on less (or more)

then 10 plots, divide the total for the entire

transect by the number of plots and use the

conversion factor in column 4.

To convert grams to pounds per acre, use the

conversions in Table 6.

Table 6 - Conversion Factors for Grams to

Pounds per Acre

Plot Size Weight Conversion Conversion

Unit Factor Factor

Per 10 Plots Per Plot

0.96 ft2 grams 10 100

1.92 ft2 grams 5 50

2.4 ft2 grams 4 40

4.8 ft2 grams 2 20

9.6 ft2 grams 1 10

96. ft2 grams 0.1 1

.01 acre grams 10 100

.1 acre grams 1 10

In the metric system, a square-meter plot (or

multiple thereof) is used. Weight on these plots

is estimated or harvested in grams and converted

to kilograms per hectare. A hectare equals 10,000

square meters. A kilogram equals 1,000 grams. If

weights are collected on 10 plots, the total

weight is converted to kilograms per hectare by

using the factor in column 3. If production is 

collected on less (or more) then 10 plots, divide

the total for the entire transect by the number of

plots and use the conversion factor in column 4.

To convert grams per plot to kilograms per

hectare, use the conversions in Table 7.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 4 – Production Data

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Table 7 - Conversion Factors for Grams to

Kilograms per Hectare

Plot Size Weight Conversion Conversion

Unit Factor Factor

Per 10 Plots Per Plot

0.25 m2 grams 10 100

1 m2 grams 10 100

10 m2 grams 10 100

100 m2 grams 10 100

400 m2 grams 10 100

Mixed Measuring Units

With large volumes of vegetative material associated with trees and large shrubs, it is more practical to estimate weights in pounds rather than

grams. The conversion factor on a per plot basis,

when weights are collected in pounds for a 96 ft2

plot, is 454. Likewise, vegetative material associated with grasses, forbs, and small shrubs is

more easily estimated in grams. Therefore, on a

per plot basis, weights collected in grams for a .1

acre plot would convert to 2.2 pounds per acre

(conversion for a 0.01 acre plot is 0.22).

Adjustment Factors

The ideal situation for determining production

data for each individual species is to sample

them when they are at their maximum production. With a diversity of species, it is impossible

to make these determinations at one point in

time during the growing season. Therefore, the

production of each species must be reconstructed

to reflect total annual production. This is accomplished using the conversion factors described

previously. 

Green Weight Adjustment Factor

This is the procedure for converting green weight,

which is the weight of vegetation estimated or

collected in the field, to air-dry weight.

ADW percentages for various types of plants

at different stages of growth are provided in

Appendix 7. These percentages are based on currently available data and are intended for interim

use. As additional data from field evaluations

become available, these figures will be revised.

ADW percentages listed in Appendix 7 can be

used for other species having growth characteristics

similar to those of the species listed. 

States that have prepared their own tables of

air-dry percentages on the basis of actual field

experience can substitute them for the tables in

Appendix 7. Be sure to check with the local

office of the NRCS for their latest ADW percentage tables. It is recommended that local field

offices develop these tables for local conditions

and species. Some interpolation must be done in

the field to determine air-dry percentages for

growth stages other than those listed. If ADW

percentage figures have not been previously

determined and included in ADW percentage

tables, or if ADW conversion factors need to be

checked, retain and dry enough harvested material

samples to determine ADW percentages. 

The relationship of green weight to ADW varies

according to such factors as exposure, amount of

shading, time since last rain, and unseasonable

dry periods. Several samples of plant material

should be harvested and air-dried each season to

verify the factors shown in Appendix 7 or to

establish factors for local use.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 4 – Production Data

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Double Sampling Adjustment Factor 

This is the adjustment factor calculated from the

double sampling process (see Double Sampling—

Estimating and Havesting, number 6). The harvested weights are divided by the estimated

weights. A factor of more than 1.0 indicates the

estimate is too low. A factor lower than 1.0

indicates the estimate is too high.

Air-dry Weight Adjustment Factor

This is the appropriate ADW percent in decimals

from tables and charts that convert green weight

to ADW based upon various stages of growth.

Utilization Adjustment Factor

This is the percent of the plant’s current growth

remaining at the time of sampling. Biomass lost

as a result of herbivory (e.g., livestock, wildlife,

insects) must be recognized and re-created in

order to provide a more accurate estimate of the

total current year’s annual production for individual species and the plant community. The

utilization adjustment attempts to restore this

missing amount of production. The examiner

determines the percent of the current year’s

growth that remains. This is actually the reverse

of percent utilized. For example, if utilization on

a plant species averages 30 percent on the production transect, the percentage of the plants

remaining would be 70 percent. Thus, the adjustment entered for that particular species would be

0.70. Utilization may vary throughout the

weight estimate plots, requiring an estimate of

the average use to determine the adjustment.

Growth Adjustment Factor

This is the percent of growth (in decimal form)

that has occurred up to the time plot data is collected. The values entered can reflect the growth

curves for the site (as listed in some site descriptions), or it could be based upon locally developed

growth curve data for each species.

Reconstructing the Present Plant

Community

The existing plant community at the time of

inventory must be reconstructed to the normal

annual air-dry production before it can be compared with the reference plant community. The

reconstruction must consider physical, physiological, and climatological factors that affect the

amount of biomass measured (i.e., weighed or

estimated) for a species at a specific point in

time. The present plant community is reconstructed by multiplying the measured weight of

each species by a reconstruction factor. The

reconstruction factor formula is:

Reconstructed (GW) (A) (B) (C) 

(D) (E)

where:

GW = Green weight

A = Plot size conversion factor

B = Double sampling adjustment factor, if

appropriate 

C = Percent of air-dry weight (ADW)

D = Percent of plant biomass of each species

that has not been removed

E = Percent of growth of each species that has

occurred for the current growing season
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Ocular Estimation of Production

Data 

Ocular estimates of production for an entire site,

as opposed to estimating production on individual

plots, is the quickest and easiest technique.

However, with inexperienced people, the

reduced accuracy resulting from this technique

limits the use of the data. Ocular estimates are

useful in quickly determining the similarity

index of a site (see Chapter 5) for use in mapping

plant communities and in stratifying SWAs for

sampling purposes. 

The following procedure is used in to become

proficient at estimating production for an SWA.

1. Estimate production, in pounds per acre or

kilograms per hectare, of individual species

on the site.

2. Estimate production of individual species on

a series of random plots.

3. Compute production in pounds per acre or

kilograms per hectare from the random plots.

To further check these estimates, harvest or

double sample according to procedures

addressed in the double sampling section of

this document.

4. Repeat procedure until proficiency is

attained.

Although this procedure misses some species of

minor importance, it provides a useful check on

estimates.

Inventory Level of Intensity

The minimum standard for an ecological site

inventory is production by species. The level or

intensity at which the production of a plant

community is determined depends on the

intended use of the data. Ocular estimates are

the quickest and easiest technique for determining

production, but may result in reduced accuracy,

limiting use of the data. Estimating production of

individual species on production plots is more

time consuming, but the accuracy of the data is

significantly increased, especially if plots are

periodically harvested and weight-unit weights

are adjusted accordingly. Harvesting is the most

accurate technique, but because of the additional

time required for collection is seldom used

except in research-type efforts. A combination of

harvesting and estimating or double sampling is

probably the best technique for documenting the

production on the site. Double sampling is the

technique NRCS uses for documenting new

ecological site descriptions and revising existing

descriptions. Even with the estimating technique,

frequent clipping studies (harvesting) should be

conducted to calibrate the observer’s eye.

Production Data for Documenting

Rangeland Ecological Sites

Data to be used for preparing rangeland ecological site descriptions and grouping soils into

rangeland ecological sites are to be obtained by

the double-sampling procedure. All documented

production and composition data are to be

recorded on the Vegetation Production

Worksheet in Appendix 4. Specific procedures

for documenting an ecological site description

can be found in the NRSC National Range and

Pasture Handbook, Chapter 4.
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INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 5 – Similarity Index

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Definition and Purpose of a

Similarity Index

THE PRESENT PLANT COMMUNITY on an

ecological site can be compared to a reference

community by the calculation of a similarity

index. In most cases, the reference community is

the historic climax plant community or potential

natural community. 

A similarity index is a comparison of the present

state of vegetation on an ecological site in relation to the kinds, proportions, and amounts of

vegetation with other vegetation communities

the site is capable of producing. It is expressed as

the percentage of a plant community that is

presently on the site. To make the comparison,

the reference vegetation communities must be

described in sufficient detail in the ecological site

description. As ecological site descriptions are

revised and further developed, they should also

include descriptions of other common vegetation

communities that can exist on the site.

The similarity index can provide managers with

a starting point for establishing specific management objectives. It also provides a means of

determining the successional status (Table 8). 

Table 8 - Successional Status

Similarity Successional

Index Status

0-25% early

26-50% mid

51-76% late

77-100% (potential natural community)

Determining Similarity Index 

A similarity index determines how closely the

current plant community resembles either the

potential natural community or some other reference community. In order to make this determination, the existing plant community must be

inventoried by recording weight, in pounds per

acre, for each species present. In determining the

similarity index, the allowable production of a

species in the existing plant community cannot

exceed the production of the species in the reference plant community. If plant groups are used,

the present reconstructed production of a group

cannot exceed the production of the group in the

reference plant community.

Table 9 demonstrates how the similarity index is

determined on four different reference communities for a loamy upland 12-16 PZ ecological site.

(Refer to Chapter 3 for information on Ecological

Sites and Appendix 3 for the ecological site

description.) Table 9 shows only one plant from

each plant group described in the ecological site

description. This is for illustrative purposes to

show the calculation of the similarity index. In

actual practice, it is desirable to list all species

found on the sample transect. This example

assumes the current plant community has been

reconstructed to actual annual production. 

Chapter 5 - Similarity Index
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 5 – Similarity Index

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On the similarity index form in Table 9, each

species is listed in column B, along with the

production for the reference plant community in

column C (pounds per acre). Current annual production for each species is shown in column D.

The allowable production in column E is determined by using the smaller of the two production

amounts (columns B or C). The total allowable

production represents the amount of the reference plant community that is currently present

on the site. The similarity index is determined

by dividing the total allowable production (total

of column E) by the total production for the

reference community (total of column C).
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Table 9 - Examples of Similarity Index Determinations on a Loamy Upland 12-16 PZ

Ecological Site

Determination of similarity index to the potential natural community

Management Unit or Allotment: Rockin’ Raindrop Examiner: Someone’s name

Ecological Site: Loamy Upland 12-16 PZ Location: Center of Horse Pasture

Reference Plant Community: Native midgrass (HCPC) Date: 8/30/96

A B C DE

Plant Species Production/acres in Annual production in Pounds

Group Name reference plant lb/acre (actual or Allowable

community (from reconstructed)

ecological site description)

1 Sideouts grama and

others from Group 1 400-500 25 25

2 Bluegrama and

others from Group 2 150-250 25 25

3 Threeawn species

others from Group 3 50-100 40 40

4 Bush muhley and

others from Group 4 50-100 25 25

5 Curly mesquite and

others from Group 5 10-50 20 20

6 Fall witchgrass and

others from Group 6 10-50 30 30

7 Six week threeawn and

others from Group 7 10-50 15 15

8 Wild daisy and

others from Group 8 100-150 5 5

9 Tansy mustard and

others from Group 9 10-15 5 5

10 Range ratany and

others from Group 10 50-100 50 50

11 Jumping cholla and

others from Group 11 10-50 160 30

12 Mesquite and

others from Group 12 10-20 600 20

Totals Average Year 1000 1,000 290

Similarity Index to Native Midgrass Community = 29% (Total of E divided by total of C)
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 5 – Similarity Index

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Table 9 - (continued)

Determination of similarity index to the mesquite-short grass vegetation state

on loamy upland 12-16 PZ site

Management Unit or Allotment: Rockin’ Raindrop Examiner: Someone’s name

Ecological Site: Loamy Upland 12-16 PZ Location: Center of Horse Pasture

Reference Plant Community: Mesquite-Short Grass Date: 8/30/96

A B C DE

Plant Species Production/acres in Annual production in Pounds

Group Name reference plant lb/acre (actual or Allowable

community (from reconstructed)

ecological site description)

1 Sideouts grama and 

others from Group 1 15-50 25 25

2 Bluegrama and

others from Group 2 300-400 25 25

3 Threeawn species and

others from Group 3 10-50 40 40

4 Bush muhley and

others from Group 4 0 25 0

5 Curly mesquite and

others from Group 5 15-100 20 20

6 Fall witchgrass and

others from Group 6 0 30 0

7 Six week threeawn and

others from Group 7 0 15 0

8 Wild daisy and

others from Group 8 10-50 5 5

9 Tansy mustard and

others from Group 9 0 5 0

10 Range ratany and

others from Group 10 10-50 50 50

11 Jumping cholla and

others from Group 11 0 160 0

12 Mesquite and 

others from Group 12 15-100 600 100

TOTALS 665 1,000 265

Similarity Index to Mesquite-Short Grass Community = 40% (Total of E divided by total of C)
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 5 – Similarity Index

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Table 9 - (continued)

Determination of similarity index to the native-short grass vegetation state

on loamy upland 12-16 PZ site

Management Unit or Allotment: Rockin’ Raindrop Examiner: Someone’s name

Ecological Site: Loamy Upland 12-16 PZ Location: Center of Horse Pasture

Reference Plant Community: Native-Short Grass Date: 8/30/96

A B C DE

Plant Species Production/acres in Annual production in Pounds

Group Name reference plant lb/acre (actual or Allowable

community (from reconstructed)

ecological site description)

1 Sideouts grama and 

others from Group 1 15-50 25 25

2 Bluegrama and

others from Group 2 300-400 25 25

3 Threeawn species and

others from Group 3 15-50 40 40

4 Bush muhley and

others from Group 4 0 25 0

5 Curly mesquite and

others from Group 5 15-150 20 20

6 Fall witchgrass and

others from Group 6 0 30 0

7 Six week threeawn and

others from Group 7 0 15 0

8 Wild daisy and 

others from Group 8 15-50 5 5

9 Tansy mustard and

others from Group 9 0 5 0

10 Range ratany and

others from Group 10 15-50 50 50

11 Jumping cholla and

others from Group 11 trace 160 0

12 Mesquite and

others from Group 12 trace 600 0

TOTALS 630 1,000 165

Similarity Index to Native-Short Grass Community = 26% (Total of E divided by total of C)
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Table 9 - (continued)

Determination of similarity index to dense mesquite vegetation state

on loamy upland 12-16 PZ site

Management Unit or Allotment: Rockin’ Raindrop Examiner: Someone’s name

Ecological Site: Loamy Upland 12-16 PZ Location: Center of Horse Pasture

Reference Plant Community: Dense Mesquite Date: 8/30/96

A B C DE

Plant Species Production/acres in Annual production in Pounds

Group Name reference plant lb/acre (actual or Allowable

community (from reconstructed)

ecological site description)

1 Sideouts grama and 

others from Group 1 0 25 0

2 Bluegrama and

others from Group 2 0 25 0

3 Threeawn species and

others from Group 3 15-50 40 40

4 Bush muhley and

others from Group 4 15-50 25 25

5 Curly mesquite and

others from Group 5 0 20 0

6 Fall witchgrass and

others from Group 6 0 30 0

7 Six week threeawn and

others from Group 7 0 15 0

8 Wild daisy and 

others from Group 8 0 5 0

9 Tansy mustard and

others from Group 9 0 5 0

10 Range ratany and

others from Group 10 0 50 0

11 Jumping cholla and

others from Group 11 0 160 0

12 Mesquite and 

others from Group 12 500-600 600 555

TOTALS 620 1,000 620

Similarity Index to Native-Short Grass Community = 100% (Total of E divided by total of C)

(Table adapted from the NRCS National Range and Pasture Handbook, 1997)
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

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Many older ecological site descriptions document the extent of individual species within the

historic climax plant community by percent of

composition rather than pounds per acre.

Production figures are presented as total weights

(pounds per acre) for normal years, favorable

years, and unfavorable years. 

To calculate a similarity index, species composition must be converted to pounds per acre.

Because the percent of composition for each

species is based on total air-dry weight (ADW),

conversion of the percentages to pounds per acre

is easy. Simply multiply the percentage for each

species by the total pounds per acre for an average year to arrive at the number of pounds per

acre for each species. Table 10 converts the percent composition (column 2) from the reference

community (found in an ecological site description) to pounds per acre (column 3). Also shown

is the annual production (column 4) and the

allowable production (column 5). Column 5 is

determined by the smaller of the two amounts

(column 3 or 4). 

Table 10 - Reference Community

Reference Community

Symbol % of PNC (Reference Average Year Annual Allowable

Community) 1000 lbs/acre Production Production

Grasses 75-85 750/850 180 180

Group 1 40/50 400-500 25 25

Group 2 15-25 150-250 25 25

Group 3 5-10 50-100 40 40

Group 4 1-5 10-50 25 25

Group 5 1-5 10-50 20 20

Group 6 1-5 10-50 30 30

Group 7 1-5 10-50 15 15

Forbs 5-10 50-100 10 10

Group 8 10-15 100-150 5 5

Group 9 1-5 10-50 5 5

Shrubs/Trees 5-10 50-100 810 100

Group 10 5-10 50-100 50 50

Group 11 1-5 10-50 160 30

Group 12 1-2 10-20 600 20
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In determining allowable production, it is important not to exceed the production of the reference community relative to each species, plant

group, or life form. In Table 10, the annual production of plant groups 1 through 10 does not

exceed production in the reference community.

In addition, the total annual production of grasses and forbs does not exceed production in the

reference community. 

In plant groups 11 and 12, annual production is

much higher than allowed in the reference community. Therefore, the most production that can

be credited is 50 and 20 pounds per acre respectively (high end of column 3). It is also important

not to exceed the allowable production for all

shrubs and trees (groups 10, 11, and 12).

However, the total annual production for all

shrubs and trees is 810 pounds and the allowable

production is 100 pounds. Since plant group 10

has already been credited with the 50 pounds

allowable, the remaining plant groups (11 and

12) can total no more than 50 pounds. Group 12

is given credit for 20 pounds, leaving 30 pounds

for group 11.

Determining Similarity Index to

the Potential Natural Community

When compared to the potential natural community, the similarity index represents the percent

of the potential natural community present on

the site. This provides a basis for describing the

extent and direction of change that has occurred.

The similarity index, coupled with the state and

transition model, can help predict changes that

could occur.

Determining Similarity Index to

Other Vegetation States or

Desired Plant Community

Determining the similarity index of the existing

plant community to one or more of the possible

vegetation states in the site description may be

desirable. After management objectives have

been developed, one specific plant community

may be identified as the desired plant community. Once the desired plant community has been

identified, it is appropriate to determine the similarity index of the existing community to the

desired plant community.

Procedures for determining a similarity index for

other vegetation communities are the same as

described for the historic climax plant community. Table 9 shows similarity index determinations

for some of the other vegetation states described

in the loamy upland 12-16 PZ. These determinations use the same transect data used in Table 9.

Refer to Chapter 3 for information on ecological

sites and Appendix 3 for the ecological site

description. These examples show only one

species from each plant group.
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INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 6 – Field Procedures

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Minimum Standards

THE MINIMUM STANDARDS REQUIRED for

an ecological site inventory are production and

composition by air-dry weight (ADW) by

species. The number of plots selected depends

on the purpose for which the estimates are to be

used, uniformity of the vegetation, and other

factors. A minimum of 10 plots should be selected for collecting production data used in documenting rangeland ecological sites or for other

interpretive purposes. If vegetation distribution is

very irregular and 10 plots will not give an adequate sampling, additional plots can be selected.

If the inventory design dictates it, fewer than 10

plots can be used.

Sampling Precision

Most uses of ecological site inventory data

would not require the calculation of a sample

size necessary to achieve a given level of precision at a given confidence level. Quantitative

monitoring studies would be one situation

requiring this calculation. However, if an inventory plan calls for a specified level of precision,

refer to Sample Size Equation number 1, pages

346–350 of Measuring and Monitoring Plant

Populations, BLM Technical Reference 1730-1.

To use this equation (or the software program

discussed in the next paragraph), an estimate of

the standard deviation is needed. This can be

obtained by taking an initial sample of quadrats

and calculating the standard deviation of the set

of total production values obtained from this

sample. The standard deviation of a set of values

is easily calculated using the statistics mode or

function on a hand calculator configured with

that option or by using the standard deviation

formula (also called “worksheet function”) on a

computer spreadsheet (e.g., the appropriate

formula in Microsoft Excel is STDEV).

The easiest way to calculate the sample size for

an ecological site inventory is to use the freeware program, PC SIZE: Consultant, which runs

on any DOS or Windows machine. Instructions

on obtaining and using it are given at the Web

site associated with the book, Monitoring Plant

and Animal Populations: A Handbook for Field

Biologists by C. L. Elzinga, D. W. Salzer, J. W.

Willoughby, and J. P. Gibbs, Blackwell Science

Inc., 2001, at 

http://www.esf.edu/course/jpgibbs/monitor/

popmonroot.html

Once there, click on “Chapter 9, Statistics,” then

on “Instructions for Using DTSTPLAN and PCSIZE: Consultant to Estimate Sample Size and

Conduct Post Hoc Power Analyses.” You'll then

get a PDF file that tells how to download PC

SIZE: Consultant and how to use it.

Site Write-up Area

For sampling and planning purposes, the landscape is divided into map units called site write-up

Chapter 6 - Field Procedures
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 6 – Field Procedures

54

areas (SWAs). A SWA is defined as the smallest

geographical unit delineation to be used as a

base for collecting vegetation data and resource

information. It is the smallest mapped soil- vegetation unit. SWA delineations are the culmination

of mapping ecological sites, vegetation communities, and administrative boundaries. Each individual SWA should consist of only one ecological

site and one plant community. The only exception

would be if two or more soil- vegetation

complexes are so intermingled that individual

ecological sites cannot be delineated. SWAs may

be mapped down to a minimum of 6 acres.

Within a single soil-vegetation unit (ecological

site and plant community), for management

purposes, SWA boundaries can be set on administrative boundaries such as allotments, pastures,

wildlife habitat areas, or watersheds. The exact

criteria for subdividing on administrative boundary

lines must be documented in the inventory plan. 

In order to compile data on a management unit

or grazing allotment basis, SWAs must not cross

accurately located management unit or allotment

boundaries. SWAs may also be delineated on soil

mapping unit or pasture boundaries as specified

in the inventory plan. The more detailed the

mapping, the greater the options are for interpretation of the data. A unique SWA number is

assigned to each SWA delineated. The number

consists of one alpha character and a consecutive

3 digit number (e.g., A001, F139, S091).

Field Inventory Mapping

Mapping must be done by trained vegetation

specialists, wildlife biologists, foresters, soil

scientists, and hydrologists (for riparian areas)

working closely together. Field mapping consists

of delineating SWAs based on present plant communities (e.g., ecological sites, forestland ecological sites, or forest types). Field mapping should

be completed prior to resource data collection. If

the inventory plan identifies the need to stratify

SWAs for vegetation data collection, the entire

inventory area must be mapped first. It is desirable

to complete mapping a year in advance of

collecting vegetation data.

Mapping Process With a

Completed Soil Survey

In areas where soil survey and ecological site

descriptions are complete, an ecological site-soil

series correlation should be available in the final

soil survey report. The survey report may also

identify soil series that support forestland ecological sites or forest types (habitat types) where

the potential plant communities have already

been defined. 

Where Order II soil surveys are completed and

ecological site interpretations have been made,

boundaries of ecological sites can generally be

determined directly from the soil map.

Order III mapping describes individual soil and

plant components at association or complex

levels. Mapping unit descriptions have been

developed that describe each association component and include locations on the landscape and

percentages of each soil. Individual ecological

sites must be delineated if individual soils in the

association have different potential historic climax

plant communities.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 6 – Field Procedures

55

Mapping Process Without a

Completed Soil Survey

In areas where soil surveys are not completed,

the NRCS must be contacted to obtain any available soil or ecological site data. The NRCS may

be able to assist in training and in establishing

the mapping legend. The mapping team must

work together in the field to achieve consistency

in SWA delineation based upon ecological sites,

forestland ecological sites, or forest types. The

soil scientist must ensure that soils are considered in delineations. If at all possible, a soil survey should be completed prior to or concurrently

with delineation of ecological sites.

Mapping Ecological Sites 

The first step in mapping SWAs is the mapping

of ecological sites. Based on soils information

and field reconnaissance, ecological sites are

delineated on aerial photos. 

Present Vegetation

Ecological sites are subdivided based on changes

in plant communities. Significant changes in the

following factors must be considered in delineating

present vegetation communities:

1. Vegetation species composition (kinds, proportions, and amounts of present vegetation)

2. Vegetation ground cover

3. Vegetation height

4. Vegetation age class (especially in forested

areas)

5. Topography

6. Other factors identified in the inventory plan

To assist in this effort, current vegetation communities can be mapped as standard vegetation

subtypes. Vegetation types are designated

according to vegetation aspect. A complete listing is given in Appendix 8. Table 11 lists some of

the more common types.

Table 11 - Common Standard Vegetation

Subtypes

Type Subtype Code

Grass Short Grass 1001

Mid Grass 1002

Tall Grass 1003

Grasslike Sedge 2001

Rush 2002

Perennial Forbs Perennial Forbs 3001

Shrub Black Greasewood 4001

Creosote Bush 4011

Winterfat 4015

Mesquite 4021

Saltbush 4030

Mixed Desert Shrub 4037

Sagebrush 4040

Mtn. Mahogany 4056

Bitterbrush 4057

Mountain Shrub 4060

Snakeweed 4071

Broadleaf Trees 5000

Conifers 6000

Pinyon 6097

Juniper 6098

Broadleaf Trees Willow 5074

Conifer Douglas Fir 6001

Cryptogams 7000

Barren 8000

Annual Grass 9000

Other 9999
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 6 – Field Procedures

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Successional Status Classification

If appropriate, ecological sites should be further

subdivided based on the successional status of

the existing plant community. This is usually

apparent on the ground as a change in the plant

community. Each distinct soil-vegetation unit

should be placed in a successional status class by

making visual estimates of species production

(see ocular estimation of production data in

Chapter 4). The mapping team should complete

the Similarity Index Form (Appendix 9) to record

these initial successional status determinations.

To make this initial determination of succession

status, compare the present plant community

with that of the potential natural community.

For the existing plant community, count as

allowable production no more than the maximum weight shown on the ecological site

description for any species in the climax community. Total the allowable production of all potential natural community species to indicate the

relative similarity index. The rating must be

between 0 and 100, depending on how closely

the existing plant community resembles the

potential natural community for the ecological

site. These estimated similarity indices can be

useful in a stratification effort.

Forest Types 

Forest types are divided into stands—uniform

plant communities of trees as to timber type, age

class, vigor, height, ground cover, and stocking.

The smallest delineated unit within a forest type

is the SWA or stand. The mapping team must

assign a SWA number to each delineated SWA.

Feature Mapping 

Any permanent cultural, topographic, and biological features, as well as existing improvements,

such as fences, roads, or water developments not

shown on existing maps should be indicated on

aerial photographs. Barriers to livestock, wildlife,

or wild horse and burros should be noted.

Water Resources

Show all water resources, such as marshes,

reservoirs, springs, seeps, or streams.

Photo Scale

The recommended standard photo scale for an

ecological site inventory is 1:24,000. The minimum size delineation for SWAs is about 6 acres

for distinct wildlife habitat areas, such as riparian

areas for food and cover and cliffs or promontories

for raptors. Table 12 shows minimum size

delineations.

Table 12 - Photo Scale Minimum Size

Delineations

Scale Acres Inches/Miles

1:20,000 4.0 3.16

1:24,000 6.0 2.64

1:31,680 10.0 2.0

Stratification

Stratification is grouping together similar SWAs

for sampling purposes. To be stratified, a SWA

must be composed of similar soil-vegetation
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 6 – Field Procedures

57

units. Since production data from one SWA will

be used for other SWAs in the stratum, it is

extremely important that sites within the stratum

be virtually identical. If there is a doubt whether

they are the same, keep them separate. 

The size of the geographical area to be stratified

is determined and documented in the inventory

plan. The complexity of the ecological situation,

as well as local needs, determines whether stratification is made by allotment, group of allotments,

environmental impact statement (EIS) area, planning unit, or field office. The inventory plan sets

forth the criteria for stratification including the

number of SWAs that need to be sampled. The

following protocols are recommended (Table 13).

Table 13 - Recommended Protocols for

Stratification

SWAs in Stratum Number of SWAs Transected

1 - 3 1

4 - 6 2

7 - 10 3

All strata are assigned a number and listed. The

SWAs within a stratum should also be listed

(Table 14).

Table 14 - Stratum Listing and SWA Listing by Stratum

Stratum Listing

Stratum SWA Ecological Site Vegetation Ecological Percent Slope 

Number Number Number Subtype Condition Slope Aspect 

0001 B001 034XY001U 1002 M 10 N

0002 B002 034XY002U 4041 E 10 N

SWA Listing by Stratum

Stratum SWA Ecological Site Vegetation Ecological Percent Slope 

Number Number Number Subtype Condition Slope Aspect 

0001 B001 034XY001U 1002 M 10 N

0001 B013 034XY001U 1002 M 10 N

0001 B021 034XY001U 1002 M 10 N

0001 B023 034XY001U 1002 M 10 N

0001 B033 034XY001U 1002 M 10 N

0001 B043 034XY001U 1002 M 10 N

0001 B051 034XY001U 1002 M 10 N

0001 B063 034XY001U 1002 M 10 N

0002 B002 034XY002U 4041 E 10 N

0002 B006 034XY002U 4041 E 10 N

0002 B012 034XY002U 4041 E 10 N

0002 B018 034XY002U 4041 E 10 N

0002 B032 034XY002U 4041 E 10 N

0002 B041 034XY002U 4041 E 10 N
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 6 – Field Procedures

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Stratums With One Transect

Data collected in the sampled transect applies to

all the SWAs not sampled.

Stratums With Multiple Transects

To determine production data for each individual

species, sum production totals for each sampled

SWA and divide by the number of SWAs. For

example, Black Grama (Bouteloua Eriopoda) occurs

in sampled SWAs A001 and A005 at 3 and 7

pounds per acre respectively. SWA A009 was not

sampled, but is in the same stratum. Total production for Black Grama for SWA A009 and all

other unsampled SWAs in the same stratum

would be 5 pounds per acre (3 lb/ac + 7 lb/ac =

10 lb/ac / 2 = 5 lb/ac). Species occurring in only

one SWA would be treated the same way.

Divide the total production by the number of

SWAs sampled. For example, if Black Grama had

not occurred in SWA A001, then production for

Black Grama in unsampled SWAs would be 4

pounds per acre (7 lb/ac/ 2 = 3.5 or 4). Populate

unsampled SWAs with the averaged production

data.

Transect Locations 

The mapping team must evaluate each SWA and

recommend the most representative place to run

the transect. Unless otherwise indicated by the

mapping team, the following guidelines should

be followed for locating the transect.

SWAs With One Soil-Vegetation Unit

(Figure 5)

Step 1.

Determine the

distance across

the longest axis

of the area to be

sampled (SWA) in

feet with a USGS

1:24,000 scale

(orthophoto quads)

map. Normally, a

transect distance

of 1/2 mile is

adequate.

Step 2. Divide

the distance

measured by 11

(the number of

plots (10) plus one) so as not to sample

on SWA boundary.

Step 3. Divide the distance between plots by

the length of your pace (i.e., two steps) to get

the number of paces between plots.

Step 4. Measure the compass bearing of the line

by protracting off the orthophoto quad or aerial

photo. 

Step 5. Proceed to starting point.

Step 6. Take photograph(s) along the transect

line.

Step 7. Pace the distance determined in Step 3

from the starting point to the first plot.

SWA A001

Figure 5 - One SoilVegetation Unit
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 6 – Field Procedures

59

SWAs With Mixed or Mottled

Patterns (Figure 6)

Where vegetation units are mixed or mottled, it

will be necessary to randomly select plots in each

soil-vegetation unit in order to collect a reliable

sample. Soil-vegetation Unit A is one soilvegetation unit that will be sampled by Transect 1.

Soil- vegetation Unit B occurs as islands surrounded by Unit A. When collecting data for

Transect 2, it will be necessary to divide Transect

2 into segments and locate some of the 10 plots

on each island of Unit B. Both transects are

within SWA F139.

The percentage of each soil-vegetation unit

within the SWA is recorded on the Vegetation

Production Worksheet in Appendix 4.

Other Options for Transect Layout 

(Figures 7a and 7b)

This option uses the same procedures used in

the “SWAs With One Soil-Vegetation Unit” section, except the distance and compass bearing of

each transect leg will have to be calculated.

1

A

B

B

B

SWA F139

2

2

2

Figure 6 - Mixed or

Mottled Soil-Vegetation Units

SWA S009

Figure 7a - A TwoLegged Transect

SWA D201

Figure 7b - A MultiLegged Transect
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 6 – Field Procedures

60

Plot Sampling 

Randomly select the beginning point of the transect. Determine the transect bearing and select a

prominent distant landmark such as a peak or

rocky point that can be used as the transect

bearing point. Production plots are placed at the

specified interval (i.e., paced or measured) along

the transect bearing.

Vegetation Production Worksheet

The Vegetation Production Worksheet, with

instructions, is located in Appendix 4. It is a sample form that can be used to record production

data on the weight estimate plots. Field offices

can use this form or develop forms to suit their

needs. Remember, when using this form, to

complete the top portion of the worksheet. 

Several data elements (e.g., landform, soil texture

class, and soil texture modifier) require specific

codes. Some of these codes are identified in

Appendix 10. Valid data entry values for other

data elements on the form can be found in the

Corporate Data Dictionary at:

http://sc2962.sc.blm.gov/datashopper/default.asp

Select Applications on the left side of the site.

At the top of the site select Elements. At the

inventory data systems site, a list of logical data

elements will appear followed by a list of physical data elements. On the logical data element

list, select Detail beside the name of the data

element and the definition will appear. At the

top, select Valid Values.
T

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Chapter 7 – Data Storage

61

THE INVENTORY DATA (ID) SYSTEM,

commonly referred to as IDS, is BLM’s database

for storing, querying, and analyzing soils, vegetation, and resource inventory data. This automated

system includes vegetation data collected using

the old Soil-Vegetation Inventory Method

(SVIM) and the current ecological site inventory

(ESI) method. It provides data for land use and

allotment management planning. Data includes

the physical characteristics of the site write-up

area (SWA), such as slope, elevation, slope

aspect, and landform; administration information,

such as resource area, planning unit, allotment,

recorder, and date of inventory; soils information,

such as soil taxon name, soil survey number, and

soil map unit number; ecological site information,

such as site name and number and ecological

status; vegetation data, such as species, estimated

production, species composition, and life cycle

and life form; and location information, such as

section, township, range, acres, surface ownership,

administrative agency, and jurisdictional agency.

The query process allows the user to determine,

for instance, the number of acres in any particular

ecological site, the occurrence of a particular

species in a given allotment or ecological site, the

total air-dry weight (ADW) production of a particular SWA or individual species, and the number

of acres in a given successional status class. IDS

can also be used to analyze the various plant

communities that occur on a specific ecological

site to select a desired plant community. 

Ecological site inventory data should be input

into IDS before field offices report the inventory

complete. For information on entering data into

IDS, contact the National Science and Technology

Center (NSTC) in Denver Colorado.

Chapter 7 - Data Storage

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Abbreviations and Acronyms

63

ADW air-dry weight

BLM Bureau of Land Management

CF conversion factor

DOQQ Digital Ortho Quarter Quads

DRG Digital Raster Graphics

EIS environmental impact statement

ESI ecological site inventory

ESIS Ecological Site Information System

FLPMA Federal Land Policy and Management Act

FSSD Field Soil Survey Database

GIS geographic information system

GPS global positioning system

IDS Inventory Data System

IDSU Inventory Data System Utilities

IHICS Integrated Habitat Inventory and

Classification System

MLRA Major Land Resource Area

MLRU Major Land Resource Unit

MOU memorandum of understanding

NAPP National Aerial Photography Program

NASIS National Soil Information System (NRCS)

NBM National Biology Manual

NCM National Cartographic Manual

NEDC National Employee Development

Center (NRCS)

NFM National Forestry Manual

NRCS Natural Resources Conservation Service

NRPH National Range and Pasture Handbook

NSH National Soils Handbook

NSSH National Soil Survey Handbook

NSTC National Science and Technology

Center (BLM)

NTC National Training Center (BLM)

PNC potential natural community

PRIA Public Rangelands Improvement Act

PZ precipitation zone

RISC Range Inventory Standardization

Committee

SSST Special Status Species Tracking

STS Species Tracking System

SVIM soil-vegetation inventory method

SWA site write-up area

USGS United States Geographical Survey

Abbreviations and Acronyms

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Glossary

65

Glossary 

-AAge class: A descriptive term to indicate the

relative age of plants.

Air-dry weight: The weight of vegetation after

it has been allowed to dry to equilibrium with

the atmosphere.

Allotment: an area of land designated and managed for grazing by livestock. Such an area may

include intermingled private, State, or Federal

lands used for grazing in conjunction with the

public lands. 

Annual production: The conversion of solar

energy to chemical energy through the process

of photosynthesis. It is represented by the total

quantity of organic material produced within a

given period of time.

Aspect: The visual first impression of vegetation

or a landscape at a particular time or as seen

from a specific point. The predominate direction

of slope of the land. The seasonal changes in the

appearance of vegetation.

At risk: Rangelands that have a reversible loss in

productive capability and increased vulnerability

to irreversible degradation based upon an evaluation of current conditions of the soils and ecological processes. At risk designation may point out

the need for additional information to better

quantify the functional status of an attribute.

Attribute (rangeland health): One of the three

components that collectively define rangeland

health; soil/site stability, hydrology function, and

integrity of the biotic community.

-BBare ground: All land surface not covered by

vegetation, rock or litter.

Basal cover (area): The cross-sectional area of

the stem or stems of a plant or all plants in a

stand. Herbaceous and small woody plants are

measured at or near ground level; larger woody

plants are measured at breast or other designated

height.

Biological soil crusts: Complex mosaics of any

or all of the following: cyanobacteria, microfungi,

algae, lichens, and mosses. They do not include

club mosses (Selaginella) or tundra.

Biomass: The total amount of living plants and

animals above and below ground in an area at a

given time.

Boot stage: The growth stage when a grass

seedhead is enclosed by the sheath of the

uppermost (flag) leaf.

Brush: A term encompassing various species

of shrubs or small trees usually considered

undesirable for livestock or timber management.

The same species may have value for browse,

wildlife habitat, or watershed protection. 

Bunch grass: A grass having the characteristic

growth habit of forming a bunch; lacking stolens

or rhizomes.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Glossary

66

-CCanopy cover: The percentage of ground covered by a vertical projection of the outermost

perimeter of the natural spread of foliage of

plants. Small openings within the canopy are

included. Canopy cover may exceed 100 percent

and is synonymous with crown cover.

Climate: The average or prevailing weather conditions for a place over a period of years.

Composition: See species composition.

Cool season plants: Plants whose major

growth occurs during the late fall, winter, and

spring. Cool season species generally exhibit C3

photosynthetic pathways.

-DDesired plant community: Of the several plant

communities that may occupy a site, it is the one

that has been identified through a management

plan to best meet the plan’s objectives for the

site. It must protect the site at a minimum.

Dominant species: Plant species or species

groups, which by means of their number, coverage,

or size, have considerable influence or control

upon the conditions or existence of associated

species.

-EEcological process: Natural processes that

function within a normal range of variation to

produce and support specific plant and animal

communities. Ecological processes include: water

cycle (the capture storage and redistribution of

precipitation); energy flow (conversion of sunlight to plant and animal matter); and nutrient

cycle (the cycle of nutrients such as nitrogen

and phosphorus through the physical and biotic

components of the environment). 

Ecological site: A kind of land with a specific

potential natural community and specific physical

site characteristics, differing from other kinds of

land in their ability to produce distinctive kinds

and amounts of vegetation and to respond to

management. Ecological sites are defined and

described with information about soil, species

composition, and annual production.

Ecological site description: A written narrative

of the description of soils, climate, vegetation,

uses, and potential of a kind of land with specific

physical characteristics to produce distinctive

kinds and amounts of vegetation.

Ecological site inventory: A resource inventory

that involves the use of soils information to map

ecological sites and plant communities and the

collection of natural resource and vegetation

attributes. The sampling data from each of these

soil-vegetation units, referred to as site write-up

areas (SWAs), become the baseline data for natural

resource management and planning.

Ecological status: See successional status.

Ecosystems: Organisms together with their abiotic environment forming an interacting system

and inhabiting an identifiable space.

Energy flow: Conversion of sunlight to plant and

animal matter; one of the ecological processes.

Erosion: Detachment and movement of soil or

rock fragments by water, wind, ice, or gravity. 
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Glossary

67

-FFacilitating practices: Practices that control or

influence the management, movement, and handling of grazing animals. These practices include

water developments (e.g., reservoirs, pipelines,

wells, catchments), stock trails, fencing, salting,

and herding.

Fauna: The animal species of a region.

Forb: Any herbaceous plant other than those

in the Gramineae (true grasses), Cyperaceae

(sedges), and Juncaceae (rushes) families (i.e., any

nongrass-like plant) having little or no woody

material on it; a broadleafed flowering plant

whose above ground stem does not become

woody and persistent.

Forestland: Land on which the potential natural

community is dominated by trees.

-GGrass: Any plant of the family Gramineae

(Poaceae).

Grasslike plant: A plant of the Cyperaceae

(sedges) and Juncaceae (rushes) families, which

vegetatively resembles a true grass of the

Gramineae family.

Ground cover: The percentage of material,

other than bare ground, covering the land surface. It may include live and standing dead vegetation, litter, cobble, gravel, stones, and bedrock.

Ground cover plus bare ground would total 100

percent.

Growing season: That portion of the year

when temperatures and moisture permit plant

growth. In tropical climates, it is determined by

the availability of moisture.

Gully: A furrow, channel, or miniature valley,

usually with steep sides, through which water

commonly flows during and immediately after

rains or snow melt.

-HHalf shrub: A plant with a woody base whose

annually produced stems die each year.

Harvest: The removal of annual vegetation

production from an area of land.

Herbaceous: Nonwoody plant growth.

Historic climax plant community: The plant

community considered to best typify the potential plant community of an ecological site prior

to the advent of European man. 

-IIncreaser: Those species that increase in

amount for a given plant community, as a result

of a specific abiotic/biotic influence or management practice. 

Infiltration: The flow of a fluid into a substance

through pores or small openings. 

Invasion: The migration of organisms from one

area to another area and their establishment in

the latter.

Inventory: The systematic acquisition and

analysis of information needed to describe,

characterize, or quantify resources for land-use

planning and management of the public lands.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Glossary

68

-LLife form: Characteristic form or appearance of

a species at maturity, such as a grass, forb, tree,

or shrub.

Litter: The uppermost layer of organic debris on

the soil surface; essentially the freshly fallen or

slightly decomposed vegetal material.

-MMajor land resource area: Broad geographic

areas that are characterized by a particular pattern

of soils, climate, water resources, vegetation, and

land use. Each MLRA, in which rangeland and

forestland occur, is further divided into ecological

sites.

Management objective: A planned result to be

achieved within a stated time period. Objectives

are subordinate to goals, are specific with shorter

timeframes, and have increased possibility of

attainment. Time periods for completion and

outputs or achievements are measurable and

quantifiable.

Monitoring: The orderly collection, analysis,

and interpretation of resource data to evaluate

progress toward meeting objectives.

-NNative pasture: Land on which native vegetation

(climax or natural potential plant community) is

forest, but which is used and managed primarily

for production of native plants for forage. Native

pasture includes cutover forestland and forested

areas that were cleared and used as cropland.

Native species: A species that is a part of the

original fauna and flora of an area.

Nonvascular plants: Plants without specialized

water or fluid conductive tissue (Xylem and

phloen) that includes bryophytes, lichens and

algae.

Noxious weed: An unwanted plant specified by

Federal or State laws as being especially undesirable, troublesome, and difficult to control. It

grows and spreads in places where it interferes

with the growth and production of desired

species.

Nutrient cycle: The cycle of nutrients, such as

nitrogen and phosphorus, through the physical

and biotic components of the environment; one

of the ecological processes.

-0-

Objective: See management objective.

-PPasture: A grazing area enclosed and separated

from other areas by a fence or natural barrier.

Pedon: The smallest body of one kind of soil

large enough to represent the nature and

arrangement of horizons and variability in the

other properties that are preserved in samples.

Pedons extend down through all genetic horizons.

Perennial plant: A plant that has a life span of

3 or more years.

Phenology: The study of periodic biological

phenomena that are recurrent (e.g., flowering,

seeding), especially as related to climate.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Glossary

69

Potential natural community (PNC): The

biotic community that would become established

if all successional sequences were completed

without interference by man under the present

environmental conditions. Natural disturbances

are inherent in development. PNCs can include

naturalized nonnative species.

-QQualitative: Observational type data that is

recorded but not measured.

Quantitative: Collection of data by measuring

vegetation or soil characteristics. 

-RRangeland: A type of land on which the indigenous vegetation (climax or natural potential ) is

predominantly grasses, grasslike plants, forbs, or

shrubs and managed as a natural ecosystem. If

plants are introduced, they are managed similarly.

Rangeland includes natural grasslands, savannas,

shrublands, many deserts, tundras, alpine communities, marshes, riparian zones, and wet

meadows. 

Rangeland health: The degree to which the

integrity of the soil, vegetation, water, and air, as

well as the ecological process of the rangeland

ecosystem, are balanced and sustained.

Rangeland similarity index: The present state

of vegetation and soil protection of an ecological

site in relation to the potential natural community

for the site.

Relict area: A remnant or fragment of the historic

climax plant community that remains from a former period when it was more widely distributed.

Rill: A small intermittent water course with

steep sides, usually only several centimeters

deep. Rills generally are linear erosion features.

Riparian zone: The banks and adjacent areas of

water bodies, water courses, seeps, and springs

whose waters provide soil moisture sufficiently

in excess of that otherwise available locally so as

to provide a more moist habitat than that of

contiguous flood plains and uplands.

Rock fragments: The unattached pieces of rock

2 mm in diameter or larger that are strongly

cemented or more resistant to rupture. Rock

fragments include all sizes that have a horizontal

dimensions less than the size of a pedon. Rock

fragments are described by size shape, and, for

some, the kind of rock.

-SSample: A set of sampling units as opposed to a

single measurement.

Seral community: See seral stage.

Seral stage: The developmental stages of an

ecological succession; synonymous with

successional stage.

Shrub: A plant that has persistent woody

stems and a relatively low growth habit, and

that generally produces several basal shoots

instead of a single bole. It differs from a tree by

its low stature, less than 5 meters (16 feet), and

nonarborescent form.

Slope aspect: The predominate direction of

slope of the land.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Glossary

70

Soil: The unconsolidated mineral and organic

material on the immediate surface of the earth

that serves as a natural medium for the growth

of land plants. The unconsolidated mineral

matter on the surface of the earth that has been

subjected to and influenced by genetic and environmental factors of parent material, climate

(including moisture and temperature effects),

macro and microorganisms, and topography.

Soil association: A kind of map unit used in

soil surveys comprised of delineations, each of

which shows the size, shape, and location of a

landscape unit composed of two or more kinds

of component soils or component soils and miscellaneous areas, plus allowable inclusions. The

individual bodies of component soils and miscellaneous areas are large enough to be delineated

at the scale of 1:24,000. Several bodies of each

kind of component soil or miscellaneous areas

are apt to occur in each delineation, and they

occur in a fairly repetitive and describable pattern.

Soil classification: The systematic arrangement

of soil units into groups or categories on the

basis of their characteristics. Broad groupings are

made on the basis of general characteristics and

subdivisions on the basis of more detailed

differences in specific properties.

Soil inclusion: One or more polypedons or

parts of polypedons within a delineation of a

map unit, not identified by the map unit name

(i.e., it is not one of the named component soils

or named miscellaneous area components). Such

soils or areas are either too small to be delineated

separately without creating excessive map or legend detail, occur too erratically to be considered

a component, or are not identified by practical

mapping methods.

Soil map unit: A collection of soil areas or miscellaneous areas delineated in a soil survey. They

may encompass one or more kinds of soil or one

or more kinds of soil and miscellaneous areas,

such as a rock outcrop. They are identified by a

unique map symbol in a survey area. There are

four kinds of map units: consociations, complexes,

associations, and undifferentiated groups.

Soil survey: The systematic examination,

description, classification, and mapping of soils

in an area. Soil surveys are classified according to

the kind and intensity of field examination.

Species composition: The proportions of

various plant species in relation to the total on a

given area. May be expressed in terms of relative

cover, relative density, or relative weight.

State: A recognizable, resistant, and resilient

complex of soil and vegetation. 

Steady state: Vegetation states that are resistant

to change. These plant communities change only

as a result of a natural event that is beyond the

normal range of events or normal human actions. 

Stratification: the grouping together of similar

site write-up areas (SWA) for sampling purposes.

SWAs must have the same ecological site, forestland ecological site, or forest type in the same

successional status class, or present vegetation

community.

Structure (soil): The combination or arrangement of primary soil particles into secondary

units or pedons. Secondary units are characterized

on the basis of size, shape, and grade (degree of

distinctness).
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Glossary

71

Structure (vegetation): The height and area

occupied by different plants or life forms in a

community.

Succession: The progressive replacement of

plant communities on a site that leads to the

potential natural plant community (i.e., attaining

stability). Primary succession entails simultaneous

succession of soil from parent material and vegetation. Secondary succession occurs following

disturbances on sites that previously supported

vegetation and entails plant succession on the

more mature soils.

Successional status: The present state of vegetation and soil protection of an ecological site in

relation to the potential natural community for

the site. Successional status is the expression of

the relative degree to which kinds, proportions,

and amounts of plants in a community resemble

that of the potential natural community. The

four classes of successional status ratings,

expressed in terms of similarity to the potential

natural community, are: 0-25 percent early seral

class, 26-50 percent mid seral, 51-76 percent late

seral and 76-100 percent PNC.

Succulent: Juicy, watery or pulpy, as the

succulent stems of cacti. 

-TThreshold: The boundary between any and all

states, or along irreversible transitions, such that

one or more primary ecological processes has

been irreversibly changed and must be actively

restored before returning to a previous state is

possible. 

Transition: A shift in plant composition that

results in relatively stable states, as reflected in

composition and structure. These shifts can

occur by natural forces or as a result of human

actions.

Transition pathway: The mechanism that

causes a change in plant community from one

steady state to another (e. g., fire, drought, grazing,

rest, chemical and mechanical treatment).

Tree: A woody perennial, usually single-stemmed

plant, that has a definite crown shape and characteristically reaches a mature height of at least 5

meters (16 feet). Some plants, such as oaks

(Quercus spp.), may grow as either trees or

shrubs.

Trend: The direction of change in a vegetation

attribute or successional status observed over

time.

-VVascular plant: Plants with vessels that conduct

sap throughout the plant.

Vegetation: Plants in general, or the sum total of

the plant life above and below ground in an area.

Vegetation attribute: The quantitative features

or characteristics of vegetation that describe how

many, how much, or what kind of plants are

present. The most commonly used attributes are

frequency, cover, density, production, structure,

and composition.

Vegetation manipulation practices: Practices

that are directed at changing vegetation production,

species composition, and erosion control. These

practices include root plowing, seeding, pitting,

chaining, prescribed fire, herbicide application,

prescribed grazing, and livestock exclusion.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Glossary

72

Vegetation type: A kind of plant community

with distinguishable characteristics described in

terms of the present vegetation that dominates

the aspect or physiognomy of the area.

-WWarm season plants: Plants whose major

growth occurs during the spring, summer, or fall

and that are usually dormant in winter.

Water cycle: The capture, storage, and redistribution of precipitation.

Watershed: The total area of land above a

given point on a waterway that contributes

runoff water to the flow at that point. A major

subdivision of a drainage basin.

Weather: The current state of the atmosphere

with regard to wind, temperature, cloudiness.

moisture, and atmospheric pressure.

Woodland sites: See forestland.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Bibliography

73

Bibliography

Batson, F.T., P.E. Cuplin, and W.A. Crisco. 1987.

Riparian area management: The use of aerial

photography to inventory and monitor riparian

areas. USDI, BLM/YA/PT-87/021+1737.

Denver, Colorado. 16pp.

Despain, D.W., P.R. Ogden, and E.L. Smith. 1991.

Comparative yield method for estimating

range production. In: B. Ruyle, ed. Some

Methods for Monitoring Rangelands and other

Natural Area Vegetation. Extension Report

9043, University of Arizona, College of

Agriculture, Tucson.

Elzinga, C.L., D.W. Salzer, and J.W. Willoughby.

1998. Measuring and monitoring plant populations, BLM Technical Reference 1730-1.

BLM/RS/ST-98/005+1730. Bureau of Land

Management, National Applied Resource

Sciences Center. Denver, Colorado. 477 pp.

Gabriels, P. C. J. and J.V. Van Den Berg. 1993.

Calibration of two techniques for estimating

herbage mass. Grass and Forage Science (1993)

Vol. 48:329-335. 

Krebs, C.J. 1989. Ecological methodology. Harper

& Row, New York, NY.

Pechanec, J.F. and G.D. Pickford. 1937. A weightestimate method for the determination of

range or pasture production. J. Amer. Soc.

Agron. 29:894-904.

Smith, E.L. and D.W. Despain. 1991. Dry-weight

rank method of estimating plants species composition. In: G.B. Ruyle, ed. Some methods for

monitoring rangelands and other natural area

vegetation. Extension Report 9043, University

of Arizona, College of Agriculture, Tucson.

Stringham, T. K., W. C. Krueger, and P. L. Shaver.

2001. States, transitions, and thresholds: further

refinement for rangeland applications. Agr.

Exp. Sta. Oregon State University. Special

Report 1024. 15 pp.

USDA, Natural Resources Conservation Service.

1997. Inventorying, classifying and correlating

Juniper and Pinyon communities to soils in

western United States. Grazing Lands

Technology Institute. Fort Worth, Texas. 

___. 1997. National Range and Pasture Handbook.

Washington, DC. 

___. 1996. National Soil Survey Handbook, 430-

VI-NSSH. Washington, DC. 

USDA, Soil Conservation Service. 1976. National

Range Handbook. Washington, DC. 

USDI, Bureau of Land Management. 1992.

Procedures for ecological site inventory—with

special reference to riparian-wetland areas.

BLM Technical Reference 1737-7. BLM/SC/PT92/004+1737. Denver, Colorado. 135 pp.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Bibliography

74

___. 1984. Manual Handbook 4410-1, National

Range Handbook. Washington, DC.

Vermeire, L.T. and R.L. Gillen. 2001. Estimating

herbage standing crop with visual obstruction

in tall grass prairie. J. Range Managment,

54:57-60.

Wiegert, R.G. 1962. The selection of an optimum

quadrat size for sampling the standing crop of

grasses and forbs. Ecology 43:125-129.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 1

75

BLM started flying aerial photography projects

on a regular basis in the late 1960s. In general,

where there are large blocks of BLM land ownership, there is usually resource scale aerial photo

coverage. 

Scale: Usually 1:24,000, some 1:12,000 (Northern

California, Western Oregon), 1:15,840 or 1:31,680

Film Type: Mostly Natural Color or False Color

Infrared (CIR), some Black and White

Years Flown: For a particular area, there may be

only 1 year of coverage or multiple years/cycles

of coverage. 

The frequency of flights varies from State to

State. Oregon has flown consistently from the

1950s through the present (Western Oregon in

particular). Colorado, Idaho, New Mexico, Utah,

and Wyoming typically have two cycles of coverage for most areas. Arizona, California, and

Nevada typically have two cycles of coverage for

only selected areas. Montana mostly has only

one cycle of coverage (typically mid 1970s

through the early 1980s only).

Special project photographs have also been completed on selected areas, typically for riparian or

photogrammetric purposes.

Scale: Usually 1:2,400 to 1:6,000 range

Film Type: Mostly Natural Color or False Color

Infrared(CIR).

Years Flown: Generally only 1 year of coverage. In

some cases, there may be multiple years/cycles

of coverage.

To determine what BLM coverage exists (e.g.,

geographic area, year flown, scale, film type) and

obtain copies of the flight line indexes, contact

the BLM State or field office aerial photo/remote

sensing contact. Most of the original film is stored

at BLM’s aerial photo archive in Denver. To order

photo reproductions or determine coverage, you

can also contact the BLM’s National Science and

Technology Center (NSTC) in Denver. Contact

Larry Cunningham (303-236-6382/ Fax 6564) or

Connie Slusser (303-236-7991/Fax 7990) at:

NSTC, ST-122,

BLM, Bldg. 50, Denver Federal Center 

PO Box 25047

Denver, Colorado 80225-0047

Other sources of aerial photo coverage include: 

U.S. Geological Survey

Earth Science Information Center

Bldg. 810, Denver Federal Center

Denver, Colorado 80225

303-202-4200

They have an extensive listing of their own coverage,

plus what other Federal, State, and county agencies,

and private companies have.

U.S. Department of Agriculture

Aerial Photography Field Office

PO Box 30010

Salt Lake City, Utah 84130

801-975-3503

They have their own coverage (Forest Service land,

Farm Service Agency, and NRCS {previously ASCS

and SCS}).

Appendix 1 - Aerial Photography 
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 1

76

There is also the National Aerial Photography

Program (NAPP). This program was started in

1987, with 5-year cycles for reflights. Most

States have been flown three times. This program

covers the entire country and may be more

recent than typical BLM coverage.

Scale: 1:40,000

Film Type: Black and White for most 1990 and

newer and CIR for 1987-1989

Years Flown: 1987 to present (3 cycles)

For determining coverage and photo numbers for

NAPP you can:

• Contact your BLM State Office or the BLM

Denver office.

• Contact the USGS or USDA (see above).

• Go to the USGS Web site.

For placing aerial photo orders from the NAPP,

contact the USGS or USDA.

For reproduction costs, please contact the BLM,

USGS, or USDA for the film they have. 

Note: BLM was a contributor from 1987 through

1994, thus we get a price break for these years.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 2

77

Draft

Technical Note

RIPARIAN-WETLAND

SOIL MAP UNIT DELINEATIONS

04/21/92

Prepared by George J. Staidl, NSRT

Background

Soil survey techniques and procedures guiding

soil surveys, soil scientists, and SCS SSQA staff

have generally concentrated on the major soil

components and map unit delineations with substantial acreage. These procedures, in conjunction

with cartographic policy, only allow for a closed

line delineation or general spot symbols to identify unique areas. Use of delineations or spot

symbols is highly dependent upon the scale of

the photobase maps. Many unique areas are

comprised of riparian zones and wetlands of

minor acreage. These unique areas contain contrasting soils and are usually the most vegetatively

productive soils within any survey area. The

typical field mapping process identifies these

areas with a broadly defined spot symbol or as

contrasting soil inclusions within map units. This

is a result of not identifying the riparian-wetland

mapping objectives in the soil survey area MOU

and the emphasis put upon the soil scientist to

increase their production of acres mapped. The

result is a tradeoff in detail of mapping and

reduced ability to provide soil information concerning riparian and wetland areas. 

The present farm bill and other congressional

legislation have emphasized preservation and

management of these unique riparian-wetland

areas. They are, for the most part, the more productive and fragile parts of the ecosystem. The

soil survey and cartographic procedures presently

in use are not conducive to identifying and delineating many of these smaller areas as soil map

units. These areas need to be part of a permanent

soil database. Without this data, quality information cannot be disseminated to the user to meet

the legislative needs. New techniques need to be

explored, tested, and implemented within the

soil survey process to give the soil scientist the

tools to incorporate past, present, and future

data into soil survey activities. 

Statement of Needs

As noted previously, congressional legislation

has pointed out a need for additional soil survey

information applicable to riparian and wetland

areas. Availability of this information for total

resource planning and conservation practice

application is also vitally important in the decision making process. It is recognized that data

collection should be initiated in many areas

thought to be of less importance, or at least

unmappable, using the policy and techniques

available to the soil scientist at the time.

Appendix 2 - Soil Map Unit

Delineations
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 2

78

Implementation would require that the resulting

soil and plant data obtained be incorporated into

a permanent database. This would maximize its

utility for present and future data dissemination.

This can be accomplished by developing a mechanism to identify these unique areas on field

sheets, orthophoto quads, and in a GIS database

where available. To maintain a permanent database, some modification of procedures will be

needed. This should include modification of

requirements using innovative cartographic techniques, map unit design, map unit descriptions,

correlation to the series and phase level, and data

entry to the soil survey database. Field applications would take into account only that which is

normally expected for delineation and documentation common to other map units. Addressing

the inequities of the present procedures will minimize the need for continued onsite investigation

where soil and vegetation data is presently maintained in a nonpermanent form. Positive changes

to the present system will maximize soil data

availability for use by managers and others. 

Requirements

A. Any modifications to the existing soil survey

procedures will be applicable to a soil survey

where: 

1.GIS capability may or may not be available.

2.Targeted areas will include:

a. New SSA(s)

b. Ongoing SSA(s)

c. Newly completed SSA(s)

d. SSA(s) undergoing update

3.The need exists for information on unique

lands (riparian-wetland areas and others)

and is presently unavailable. 

B. Development and expansion of procedures for

implementation will: 

1. Be incorporated into any existing GIS

database where the potential exists.

2. Allow for the correlation of minimal acreage

unique soils to the series level. This will

initiate data entry into the soil survey

database. 

3. Allow for the correlation of minimal acreage

unique soil mapping units. This will initiate

data entry into the soil survey database.

4. Provide techniques for unique delineations

and spot symbols that will represent map

units, but do not meet the present cartographic requirements.

5. Provide procedures to use the unique

delineations and spot symbol map units to

represent spatial area and allow for acreage

determination. 

6. Allow for the description of spatial area

concepts for the unique delineation and

spot symbol map units as a component in

map unit descriptions. 

C. Proposed methods for use in soil survey areas:

1.Line segment (e.g., dot to dot or line break

to line break) vector format. 

a. Determine and designate the representative delineations line segment width for

each map unit (e.g., the map unit line

segment represents an average width of

120 feet). This information, along with

the line length and scale of map, will

determine map unit acreage. 
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 2

79

b.Suggested line width groupings are 1-50,

50-100, 100-150, and 150-200 feet. Areas

that are greater than 200 feet wide will

typically be located by an enclosed line

polygon. 

c. Assign a map unit symbol to each line

segment using a leader technique. A

unique Alpha or Numeric code, representing an average width within a line

segment group, will be assigned as the

last character in the map unit symbol. An

example of a symbol is 103X, where

“103” is the map unit name and “X” indicates an average width of 75 feet in the

50-100 feet group.

d.Utilize the existing drainage spot symbols

as line segment breaks to minimize map

clutter. 

2. Spot symbols. 

a. Use ad hoc symbols or a dot to represent

a map unit. 

b.Determine the acreage that each spot

symbol or dot represents for the map

unit (e.g., averages 2.5 acres). Suggested

spot symbol grouping are <1, 1-2, 2-3, 3-

4, and 4-5 acres. Those areas that are

greater than 5 acres will typically be

located by an enclosed line polygon. 

c. Assign a map unit symbol to each spot

symbol or dot using the leader technique. A unique Alpha or Numeric code

representing an average acreage for the

spot symbol group will be assigned as

the last character in the map unit symbol. An example of a symbol is 103P,

where “103” is the map unit name and

“P” indicates an average acreage of .5

acres for the <1 acre group.

D. Field procedures for soil survey areas:

1. Field check the area to be mapped in terms

of the normal map unit concept. 

2. Design a map unit using accepted soil survey

procedures. 

3. Determine if the map unit is a consociation,

association, complex, or undifferentiated

group.

4. Identify each major and minor component

soil within the proposed map unit, preferably

at the soil series level, and assign phases as

needed.

5. Obtain all necessary documentation for

soils, vegetation, hydrology, etc. 

6. Using the documentation collected, correlate

each major soil component of the map unit

to the series level. 

7. Assign each new map unit its own unique

map unit symbol and display with representative line segments or spot symbols on the

soil map. 

8. Designate the representative line segment

width and spot symbol acreage in each

applicable map unit description. 

9. Determine acreage for each line segment or

spot symbol on each completed soil map. 

10. Continue using accepted National

Cooperative Soil Survey procedures

throughout the survey. 
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 2

80

E. Delineation and map symbol application will

be as follows:

1. Line segments or spot symbols will be on

original field sheets and orthophotoquad

soil maps. 

2. Line segments or spot symbols will be on

registered mylar overlays with a stable base

map. 

3. Line segments or spot symbols will be

transferred to scribe coat of orthophotoquad

for publication processes.

4. Line segments and spot symbols will be

digitized as part of the GIS database. 

F. Data permanence procedure within the soil

survey area: 

1. Identify and implement the soil mapping

options noted in (E) above that are applicable

to the soil survey area status.

2. Undergo the review and final correlation

process common in any soil survey as

outlined in the National Soils Handbook. 

3. Prepare and process all necessary soil series

and map unit information into the National

Soil Survey Database for future access of

output data. 
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 3

81

United States Department of

Agriculture, Natural Resources

Conservation Service

Ecological Site Description

Rangeland

Site name: Loamy Upland 12-16 PZ

Site number: R - 041XC313AZ

Major land resource area: 41 - Southeastern

Arizona Basin and Range

Interstate correlation: None

Physiographic features

This site occurs on fan and stream terraces. The

elevations range from 3,200 to 5,200 feet above

sea level. This site occurs on all aspects of the

slope. The slopes on this site range from 1% to

15%.

Climatic features

Frost-free period: 170-220 days - Feb.20 - Nov.25

Freeze-free period: 180-225 days - Feb.15- Nov.30

Mean annual precipitation: 12-17 inches

Mean annual air temperature: 68.0  ̊F

Mean annual soil temperature: 70.0  ̊F

Monthly moisture and temperature distribution:

Mean Percent Mean

precipitation precipitation temperature

(in) (%) ( ̊F)

January 0.93 6.65 51.1

February 0.78 5.6 53.8

March 0.71 5.2 57.8

April 0.45 3.2 65.0

May 0.21 1.5 73.2

June 0.29 2.1 82.9

July 2.82 20.3 86.2

August 2.56 18.4 84.0

September 2.07 14.9 80.4

October 1.15 8.3 70.4

November 0.87 6.3 58.7

December 1.05 7.6 52.0

Mean annual 13.89 100 68.0

Other climatic features

Precipitation in the subresource area ranges from

12 to 16 inches yearly in the eastern part with

elevations from 3,600 to 5,000 feet. Precipitation

in the western part ranges from 13 to 17 inches

yearly with elevations from 3,300 to 4,500 feet.

Winter - summer rainfall ratios are 40:60 in the

west side of the resource area to 30:70 in the

eastern portion of the area. Summer rains fall

July - September, originate in the Gulf of Mexico

and are convective, usually brief, intense thunderstorms. Cool season moisture tends to be frontal,

Appendix 3 - Ecological Site

Description
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 3

82

originates in the pacific and Gulf of California, and

falls in widespread storms with long duration

and low intensity. Snow rarely lasts more than 1

day. May and June are the driest months of the

year. Humidity is generally very low.

Temperatures are mild. Freezing temperatures

are common at night from December through

April, however, temperatures during the day are

frequently above 50  ̊F. Occasionally in

December to February, brief periods of 0  ̊F

temperatures may be experienced some nights.

During June and rarely during July and August

some days may exceed 100  ̊F. Frost free days

range from 170 to 220.

The cool season plants start growing in the early

spring and mature in early summer. The warm

season plants take advantage of the summer

rains and are growing and nutritious from July

through August. Warm season grasses may

remain green throughout the year.

Associated water features

Nonstream characteristics: None

Stream characteristics: None

Soils

The soils on this site are very deep. They have

been formed in loamy alluvium of mixed origin.

Surfaces range from very gravelly sandy loam to

loam. Sandy loam surfaces can be no thicker

than 4 inches (8 inches for gravels). These soils

all have argillic horizons near the surface. Plantsoil moisture relationships are good. Soil surfaces

are dark colored.

Major Soil Taxonomic Units correlated to this site

include:

Whitehouse 1, sl

Bernardino 1(15% slope)

Caralampi 1, sl (15% slope)

Sasabe 1, sl

Enzian 1, sl

Forrest 1

McAllister 1

Plant communities

Historic climax plant community: The interpretive

plant community for this site is the Historic

climax plant community. This community is

dominated by warm-season perennial grasses.

All the major perennial grass species on the site

are well dispersed throughout the plant community. Perennial forbs and a few species of low

shrubs are well represented on the site. The

aspect of this site is that of an open grassland.

Major plant species composition

This list of plants and their relative proportions

are based on near normal years. Fluctuations in

species composition and relative production may

change from year to year dependent upon abnormal precipitation or other climatic factors. The

historic climax plant community has been determined by study of rangeland relict areas, or areas

protected from excessive grazing. Trends in plant

communities going from heavily grazed areas to

lightly grazed areas, seasonal use pastures and

historical accounts have also been used.
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 3

83

Grasses and Grasslikes 750-850 pounds per acre

Scientific plant Common name Group Pounds Percent Percent

symbol per acre by weight allowable

for group

BOCU sideoats grama 1 400-500 40-50

ERIN plains lovegrass 1

BOBA3 cane beardgrass 1

BOER4 black grama 2 150-250 15-25

BOGR2 blue grama 2

BOHI2 hairy grama 2

BOCH sprucetop grama 2

LYPH wolftail 2

ARIST threeawn species 3 50-100 5-10 5-10

DICA8 Arizona cottontop 4 5-10

SEMA5 plains bristlegrass 4

HECOl0 tanglehead 4

TRSE crinkleawn 4

MURI purple muhly 4

MUPO2 bush muhly 4

HIBE curly mesquite 5 10-50 1-5

BORO2 rothrock grama 5

BOFI slender grama 5

SPCR sand dropseed 5

MUE aparejograss 5

PAOB vine mesquite 6 10-50 1-5

LECO fall witchgrass 6

PAHA Hall panicum 6

TRPU2 fluffgrass 6

PAMU3 pima pappusgrass 6

SPCO4 spike dropseed 6

LEDU green sprangletop 6

ENDE spike pappusgrass 6

SIHY bottlebrush squirreltail 6

TRMU slim tridens 6

BORA purple grama 6

BOTR2 red grama 6

ARAD six weeks threeawn 7 10-50 1-5

AROL annual threeawn 7

BOBA2 six weeks grama 7

BOAR needle grama 7

VUOC six weeks fescue 7

PAAR Arizona panicum 7

BRLAR4 Arizona brome 7

LEFI red sprangletop 7

EUN2 Mexican sprangletop 7

ERAR desert lovegrass 7

ERDI spreading lovegrass 7

CHVI featherfinger grass 7
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Forbs 100 to 150 pounds per acre

Scientific plant Common name Group Pounds Percent Percent

symbol per acre by weight allowable

for group

SIPR2 sida 8 100-150 10-15

TAAU talinum 8

ERDI4 wild daisy 8

SPNA4 desert globemallow 8

BRDE small matweed 8

HODE hog potato 8

BRPU2 covena 8

ANTU wind flower 8

HASP2 spiny haplopappus 8

CRCO11 leatherweed 8

OEPR evening primrose 8

VIAM vetch 8

FRAR2 snake cotton 8

PLIN trailing four o'clock 8

STPA4 wire lettuce 8

POGR5 yerba de venado 8

DYPO dogbane dyssodia 8

BAAB bahia 8

TILA2 honeymat 8

ASTRA loco species 8

LOSAB mares fat 8

PORTU pursley species 8

ASTER annual aster 8

TRADE spiderwort 8

CINE thistle 8

PLIN3 Indianwheat 8

ERTE13 bull filaree 8

PEPA2 chinch weed 8

ERIOG annual buckwheat 8

ANODA anoda 8

ARABI rock cress 8

DYAC Texas dyssodia 8

BAMU desert marigold 8

JAGR slender janusia 8

PSORA breadroot 9 10-15 1-5

VIAN annual goldeneye 9

DEPI tansy mustard 9

PHYSA tomatillo 9

GALLI blanket flower 9

CHENO lambsquarter 9

AMTE3 fiddleneck 9

LUSP2 desert lupine 9

PHLOX phlox 9

LILE blue flax 9

BELY green eyes 9

PENA desert holly 9

ERDI2 diffuse eriastrum 9
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Shrubs and Trees 100- 150 pounds per acre

Scientific plant Common name Group Pounds Percent Percent

symbol per acre by weight allowable

for group

CAER false mesquite 10 50-100 5-10

ERWR shrubby buckwheat 10

KRPA range ratany 10

ZIPU desert zinnia 10

ZIGR Texas zinnia 10

KRLA spreading ratany 10

OPAR2 pencil cholla 11 10-50 1-5

OPFU jumping cholla 11

OPEN Engelmann pricklypear 11

ECHIN3 hedgehog cactus 11

MOMI pincushion cactus 11

CORYP coryphantha 11

OPVE staghorn cholla 11

OPLE Christmas cholla 11

ECWI fishhook barrel cactus 11

FOSP2 ocotillo 11

AGPA desert agave 11

YUEL soaptree yucca 12 10-20 1-2

YUBA datil yucca 12

EPTR longleaf Morman tea 12

LYCIU wolfberry 12

ATCA2 fourwing saltbush 12

BAPT yerba de pasmo 12

PRJU mesquite 12

PAFL6 blue paloverde 12

ACGR catclaw acacia 12

ACCO2 whitethorn 12

MIBI8 catclaw mimosa 12

MESC twinberry 12

JUMO oneseed juniper 12

NOMI sacahuista 12

PAAC3 retama 12

HATE burroweed 12

GUSA2 broom snakeweed 12

GUMI threadleaf snakeweed 12

MIDY velvet-pod mimosa 12

ELCE tarbush 12

PAMI5 littleleaf paloverde 12

PSCO2 whitestem paperflower 12

ZIOB greythorn 12
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Ground cover and structure

Height above the ground

Not applicable 6 - 12 inches 12 - 24 inches 24 - 60 inches 180 - 240 inches

% ground % canopy % ground % canopy % ground % canopy % ground % canopy % ground %canopy

cover cover cover cover cover cover cover cover cover cover

Trees <1 1-3

Shrubs 2-3 5-7

Forbs 2-3 5-7

Grasses 10-12 20-25

Litter 7-10

Cryptogams <1

Coarse fragments 5-10

Bare ground 60-70

Total annual production

The historic climax plant community will produce approximately the following amounts of air

dry vegetation per acre:

Favorable year: 1,500 lb/ac

Normal year: 1,000 lb/ac

Unfavorable year: 650 lb/ac

Ecological dynamics and major plant

community types

With continuous heavy grazing, palatable perennial

grasses, such as blue grama, hairy grama, sprucetop grama, sideoats grama, and plains lovegrass,

decrease. Increasers under such circumstances

include curly mesquite, threeawn species, and in

places, false mesquite. With severe deterioration,

shrubby species increase to the point of dominance. Mesquite forms the overstory with snakeweed and lesser amounts of burroweed in the

understory. Cholla and pricklypear can also

increase on the site. When present on the site,

mesquite tends to be short, due to the presence

of clay horizons at shallow depths in the soils.

Loss of porous surface soil causes a reduction in

the sites ability to effectively use intense summer

rainfall. Natural fire may have been important in

the development of the historic climax plant

community. Lehmann lovegrass can invade this

site, but usually does not become dominant.

The potential for the site to maintain its annual

production is reduced by increasing mesquite

canopy. Stable areas of the site can produce

effective herbaceous covers with up to 10%–15%

canopy cover of mesquite. In areas where halfshrubs dominate the understory, the potential

production of perennial grasses is about 10%

greater than the present production of halfshrubs

once they are removed from the plant community

by fire or other brush management.

There have been no special emphasis species

identified on this site. As that information

becomes available it will be included. Following

is a description of the present day plant communities that can occupy this site. The diagram

illustrates the transition pathways between the

common plant communities on the site.
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Transition pathways legend

PG=Prescribed grazing

CHG=Continuous heavy grazing

F=fire

HG=Heavy grazing

NF=No fire

BM=Brush management

SF=Some fire

Seed=Seeding

INV =invasion

Native midgrass

historic climax

plant community

MesquiteshortgrassNative

shortgrass

Mesquitehalf shrub

MesquiteLehman

lovegrass

INV

INV

CHG-PG HG-NF

HG

BM-PG HG-NF-INV

BM-seed BM-seed

CHG

BM-DG

HG-NF

HG-NF

BM-PG

CHG-SF

PG

Tarbushwhitehorn

Dense

mesquite

Lehmann 

lovegrass-cochise

lovegrass

Native midgrass-This is the historic climax

plant community for this site. This plant community evolved through the holocene in the

absences of grazing by large herbivores and with

fire frequency of every 10 to 20 years. It exists

all across the upper end of this MLRA especially

on moderate slopes with very gravelly surfaces.

The typical plant community description for this

vegetation state is described in detail above.

Native short grass-This plant community exists

all across the upper end of the MLRA. It is especially common on nearly level slopes with little

or no gravel cover. It is characterized by a continuous cover of short grama grasses (blue, black,

sprucetop), curly mesquite and low shrubs

(calliandra and krameria). It is stable unless basal

cover falls below 5%–6% on 2%–3% slopes.

Average production is less than historic climax

plant community as the more shallow rooted

community cannot fully exploit the soil, water, and

nutrients available in average or better growing

seasons. It is excellent for livestock grazing, but

lacks mid-grass cover needed by some wildlife

species (antelope fawns). The grass cover is easily

thinned by drought, but usually recovers rapidly.

The transition pathway included heavy grazing

with some occurrence of fire. The water cycle

has been severely altered, as has the nutrient

cycle. This community occurs in the healthy, at

risk and unhealthy recoverable categories.
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The following represents the typical plant

community of the vegetation state described as

Native-Short Grass. Refer to the Historic climax

plant community for the plants in each plant

group.

Plant group Pounds per acre

1 15-50

2 300-400

3 15-50

5 15-150

8 15-50

10 15-50

11 T

12 T

Total annual production 630 lb/ac (normal year)

Mesquite short grass-This plant community

exists all across the MLRA. Mesquite canopy

ranges from 1%–10%. The understory is a

continuous cover of short grama grasses and/or

curly mesquite. It is stable unless basal cover falls

below 5%–6% on 2%–3% slopes. Production is

always less than the historic climax plant community. Mesquite exploits the soil, water, and

nutrients earlier in the spring and to a greater

depth than the shallow rooted warm-season

grasses. The grass cover is easily thinned by

drought and may be slow to recover due to the

presence of mesquite. It is good for livestock

grazing, but the tree cover can interfere with

livestock handling operations. The presence of

mesquite allows species, such as mule deer and

javelina, to use this site, but detract from its

value as antelope habitat. The transition pathway

includes heavy grazing, no fires, and a proximity

to mesquite in bottom-lands. The ecological

processes of water cycle, nutrient cycle, and

energy flow have been severely altered. The

hydrologic functioning of this site has been

altered. This site occurs most often as at risk and

unhealthy recoverable categories.

The following represents the typical plant

community of the vegetation state described as

Mesquite-Short Grass. Refer to the Historic

climax plant community for the plants in each

plant group.

Plant group Pounds per acre

1 15-50

2 300-400

3 15-50

5 15-100

8 15-50

10 15-50

12 15-150

Total annual production 665 lb/ac (normal year)

Mesquite halfshrub/cacti-This plant community

exists all across the lower and mid portion of the

MLRA. Mesquite canopy ranges from 1%–10%.

The understory is a diverse mixture of cacti,

burroweed, broom snakeweed, and other shrubs.

Perennial grasses exist in trace amounts only. The

plant community is poor for livestock grazing,

poor for some wildlife species (e.g. pronghorn

antelope and scaled quail) and good for other

wildlife species (e.g., mule deer, javelina, and

gambel quail). Transition pathway is from

mesquite short grass with continued heavy

grazing and the absence of fire. Almost all the

ecological processes on this site have been

severely altered, and the site has lost some of the

recovery mechanisms. In general, the site is not

stable in this plant community and occurs most

often as unhealthy recoverable category.

The following represents the typical plant

community of the vegetation state described as
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Mesquite-Shrub-Cacti. Refer to the Historic

climax plant community for the plants in each

plant group.

Plant group Pounds per acre

2 15-50

3 15-100

4 15-50

7 15-50

11 15-150

12 500-600

Total annual production 750 lb/ac (normal year)

Dense mesquite-This plant community occurs

all across the MLRA in small areas, especially

historic heavy use areas, such as old homesteads,

in horse pastures, along streams with perennial

flow and other old watering locations, and also

on archaeological sites. Mesquite canopy ranges

from 10%–30%. The understory consists of

scattered low shrubs, remnant perennial grasses,

and annual species. This plant community is

very poor for livestock grazing and poor quality

habitat for most wildlife species. However,

under the present hunting pressure in southern

Arizona, the oldest and largest mule deer bucks

use these mesquite thickets as hiding and escape

cover. The site in this plant community is not

stable. Often times so much of the soil surface

has been lost under this condition that the site

will not respond to treatment and the site potential has been lost. In some cases the erosion has

so damaged the site that even the existing

mesquite trees have difficulty surviving.

Transition pathway is from mesquite short grass

with excessive grazing and no fires. This site

occurs most as unhealthy recoverable and

unhealthy unrecoverable categories.

The following represents the typical plant

community of the vegetation state described as

Dense Mesquite. Refer to the Historic climax

plant community for the plants in each plant

group.

Plant group Pounds per acre

3 15-50

4 15-50

12 500-600

Total annual production 620 lb/ac (normal year)

Tarbush/Whitethorn-This plant community

occurs throughout the eastern portion of the

MLRA in areas where loamy upland is adjacent

to limy sites that naturally support tarbush and

whitethorn. Canopy cover of the two shrubby

species usually exceeds 10%. The understory

consists of scattered low shrubs, remnant perennial grasses and annuals. This plant community is

very poor for livestock grazing and poor quality

habitat for most wildlife species. The site under

this plant community is not stable. Often so

much surface soil has been lost that the site will

not respond to treatment and the site potential

has been lost. Transition pathway is from native

mid-grass with heavy grazing, no fires, and a

proximity to tarbush/whitethorn on adjacent limy

sites. This site occurs most as unhealthy recoverable

and unhealthy unrecoverable categories.
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The following represents the typical plant

community of the vegetation state described as

Tarbush-Whitethorn. Refer to the Historic

climax plant community for the plants in each

plant group.

Plant group Pounds per acre

1 15-50

2 15-50

3 15-100

4 15-100

8 15-50

10 15-50

12 500-600

Total annual production 800 lb/ac (normal year)

Mesquite-Lehmann lovegrass-This plant community occurs throughout the MLRA. In nearly

all cases it has developed from mesquite native

grasslands in the last 30 years. Livestock grazing,

fire, and drought have all been demonstrated to

enhance this invasion of loamy upland site

wherever there is a seed source of Lehmann

lovegrass. This plant community offers a great

deal of stability to the site. Mesquite canopy is

usually less than 10%. Lehmann production

equals or exceeds native grass production.

Species diversity is usually greatly reduced on

this site once Lehmann lovegrass has become

dominant. Under mesquite native grass conditions it is common to find 40 to 50 perennial

plant species on this site. Under Lehmann dominance that figure will be 20 to 30 species. This

plant community is good for livestock grazing. It

is fair for some species of wildlife (mule deer and

gambel quail). It is good for small herbivores

(rabbits and mice) and generally poor for many

other species, such as pronghorn antelope and

scaled quail. Transition pathway is from

mesquite short grass with heavy grazing, some

fires, and a Lehmann lovegrass seed source.

The ecological processes on this site have been

altered somewhat, and this site occurs as

healthy, at risk, and unhealthy recoverable

categories.

The following represents the typical plant

community of the vegetation state described as

Mesquite-Lovegrass. Refer to the Historic

climax plant community for the plants in each

plant group.

Plant group Pounds per acre

2 15-50

8 15-50

10 15-50

12 50-150

13 1,200-1,400 (consists

of introduced lovegrasses, 

such as Lehmann, Cochise, 

Boer, and Wilman)

Total annual production 1,425 lb/ac (normal year)

Lehmann lovegrass and/or Cochise lovegrassThis plant community occurs throughout the

MLRA. It exists where mechanical brush management was used to control mesquite, tarbush,

whitethorn, and cacti, and where lovegrass

species were seeded. This plant community

offers a great deal of stability to the site. Because

of the nature of the grass species and the

mechanical roughening of the soil surface, these

communities generally produce 20–50% more

than native grass communities. Although plant

species diversity is low in these lovegrass communities, it is usually better than in the woody

dominated plant community it replaced. This

community is good to very good for livestock

grazing, fair for some wildlife species pronghorn

antelope and scaled quail), good for other species
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(rabbits and mice), and poor for such species as

mule deer and javalina. The transition pathway

is from either mesquite halfshrub/cacti or dense

mesquite, with the inclusion of mechanical brush

management and seeding of one or both of the

lovegrass species. The ecological processes are

functioning relatively similar to that of the historic climax plant community. This site most

often occurs in the healthy category.

The following represents the typical plant

community of the vegetation state described as

Lehmaun lovegrass-Cochise lovegrass. Refer

to the Historic climax plant community for the

plants in each plant group.

Plant group Pounds per acre

1 15-50

2 15-100

8 15-50

10 15-100

13 1,250-1,450 (consists

of introduced lovegrasses,

such as Lehmann, Cochise,

Boer, and Wilman)

Total annual production 1,495 lb/ac (normal year)

Plant Growth Curves

Growth curve number: AZ0001

Growth curve name: Native 1

Growth curve description: Native plant community with high similarity index and average growing conditions.

Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec.

5 5 5 3 2 2 20 20 18 10 5 5

Growth curve number: AZ0002

Growth curve name: Native 2

Growth curve description: Native plant community with low similarity index dominated by mesquite and cacti, and average

growing conditions.

Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec.

5 5 5 10 15 25 10 5 5 5 5 5

Growth curve number: AZ0003

Growth curve name: Mesquite-Lehmann lovegrass

Growth curve description: Plant community dominated by mesquite with and understory of Lehmann lovegrass, average

growing conditions.

Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec.

5 5 5 10 15 15 15 10 5 5 5 5
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Animal community

The plant community on this site is well suited

to grazing by both domestic livestock of all kinds

and by wildlife at all seasons of the year.

Currently the majority of the livestock use on

this site is with mother cows in a cow-calf operation. Historic use has always been a cow/calf

type operation, but there have been periods of

large numbers of stocker cattle on these ranges.

Sheep use has been slight historically. The main

problem to the use and management of livestock

on this site is the lack of natural water sources.

This site is important for many wildlife species.

Major species include desert mule deer, pronghorn

antelope, gambels quail, scaled quail, and blacktailed jackrabbit. Water developments are very

important to these and other wildlife on this site.

Being an open grassland, this site is also home to

a variety of small herbivores, birds, and their

associated predators. With the exception of

pronghorn antelope, this site is mainly a forage

area for larger wildlife species. The value of this

site for food or cover requirements for specific

wildlife species changes with the changes in the

vegetation that occur from one plant community

to another. Each plant community and each animal

species must be considered individually. General

information has been included here and in the

ecological dynamic section of this site description.

Associated site-This site is associated with the

Limy Upland 12-16 PZ and the Loamy Bottom sites.

Similar sites-With the historic climax plant

community, this site is not similar enough to any

other site to cause a problem or concern. As this

site deteriorates it may easily be confused with

other deteriorated sites, such as Limy Upland.

Many sites will deteriorate into very similar

plant communities.

Site Documentation

Author: Original WHN 1976 

Revised DGR 1987

Supporting data for site development-The historic climax plant community has been determined

by study of rangeland relict areas or areas protected

from excessive grazing. Trends in plant communities

going from heavily grazed areas to lightly grazed

areas, seasonal use pastures, and historical accounts

have also been used. The following transect and

clipping data also documents this site. There are 21

permanent transect locations on this site.

Sampling technique EC GC FC PC

SCS-Range 417 10 15 15 3

SCS AZ-Range-1 1 7 10 13

Type locality:

Pima Co Buenos Aires NWR, Sec. 19,

T21S, R8E

Cochise Co. Oak Ranch, Sec.2, T18S, R28E

Cochise Co. Ft. Huachuca, Sec.17, T21S,

R19E unsurveyed

Santa Cruz Co. Santa Fe Ranch, Sec. 13, T23S, R14E

Pinal Co. Tom Mix Hwy ROW, Sec.2,

T10S, R13E

Field offices:

Casa Grande Chandler

Douglas Phoenix

Safford San Carlos

Sells Tucson

Willcox

Relationship to other established classificationsThis site would most closely fit A.W. Kuckler’s

Potential Natural Vegetation as unit number 58

Grama - Tobosa - Shrubsteepe. It most closely fits the

Society for Range Management’s Rangeland Cover

Types as unit number 505 Grama - Tobosa Shrub.
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93

Plant species index-(This section provides a

cross reference for common names, scientific

names, and national symbol. It will be generated

by ESIS, no input required here.)

Other references (list other references used in

the description or correlation of this site.)

Site approval-This site has been reviewed and

approved for use. 

State Rangeland Management Specialist 

Date

Ecological site interpretations

Grazing

The plant community on this site is suitable for

grazing by all classes of livestock at any season.

With thin, course textured surfaces, and over

argillic horizons, these soils become less effective

in catching summer rainfall if the grass cover is

disturbed or depleted. With a good grass cover,

the clayey subsoil releases moisture slowly to

the plants over the summer season. Lehmann

lovegrass can invade this site slowly, but seldom

forms a monotype. At the first sign of invasion,

proper use of the native perennials must be

practiced to avoid letting lovegrass spread.

Herbaceous forage is deficient in protein in the

winter. This site has no natural surface water

associated with it; therefore, water development

for livestock is necessary for utilization of this

site.

Initial starting stocking rates will be determined

with the landowner or decision maker. They

will be based on past use histories and type and

condition of the vegetation. Calculations used to

determine an initial starting stocking rate will be

based on forage preference ratings.

Forage preferences by season for cattle

(P = preferred, D = desirable, U = undesirable)

Plant species Dec/Feb March/May June/Aug Sept/Nov

Sideoats grama U P P P.

Plains lovegrass U P P P

Cane beardgrass U D P D

Blue grama D P P P

Sprucetop grama D P P P

Curly mesquite D P P P

Harry grama D P P P

Spidergrass U U D U

Red threeawn U D U U

Perennial forbs P P P P

False mesquite U P D P

Ratany species P P D P

Zinnia species P P D P

Mesquite U (leaves) P (new leaves) P (beans) P (beans)

Staghorn cholla (fruits) P D P P

Pricklypear (fruits) U U P P
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Wildlife

This site has no natural surface water associated

with it. Water developments are important to

wildlife on this site. Being an open grassland,

this site is home to a variety of small herbivores,

birds, and their associated predators. Except for

pronghorn antelope, this site is mainly a foraging

area for the larger wildlife. There are no threatened or endangered wildlife species that rely on

this site for any of their habitat requirements.

Hydrology data

The hydrology of this site is characterized by

high intensity thunderstorms during summer

months and, in winter, by low intensity frontal

storms. From 60 to 70% of the annual moisture

occurs during the summer months. The site has

a porous soil surface that is resistant to erosion

when perennial vegetation cover is sufficient to

protect the site from damage. As basal cover is

reduced, the surface soil is exposed to accelerated

erosion and can be quickly lost. The clayey

subsoil is more resistant to erosion, but is not

able to sustain the original plant community.

Deteriorated sites are characterized by low

Guide to site plant use by selected wildlife species

(P = preferred, D = desirable, U = undesirable, X = used, but degree of utilization unknown)

Plant species Desert Pronghorn Gambels Scaled Blacktailed 

mule deer antelope quail quail jackrabbit

Perennial grasses 2.5% diet 3% diet P)seed P)seed P)foliage

Annual grasses 2.5% diet 3% diet P)seed P)seed P)foliage

Annual forbs P)green P)green P)sd/gr P)sd/gr P)foliage

Sida P)foliage P)foliage P)seed

Evolvulous P)foliage P)foliage

Dychoriste P)foliage P)foliage

Cudweed P)foliage P)foliage P)foliage

Wild daisy P)foliage P)foliage P)seed X)seed P)foliage

Globe mallow P)foliage P)foliage P)seed X)seed P)foliage

Ragweed D)foliage P)foliage

Hog potato X)foliage P)seed

Covena P)foliage X)foliage X)seed

False mesquite P)lvs/twg P)lvs/flw P)seed P)seed X)foliage

Ratany species P)lvs/twg X)foliage

Zinnia X)lvs/twg X)foliage

Yerbe-de-pasmo X)lvs/twg X)leaves

Mesquite P)lvs/bn P)bean P)seed P)seed P)lvs/bn

Staghorn cholla P)fruits P)flw/frt P)seed P)seed

Prickly pear P)fruits P)flw/frt P)frt/sd P)frt/sd P)pads

Ocotillo D)flowers X)lvs/flw

Barrel cactus P)fruits P)fruits P)seed P)seed

Agave P)flowers
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infiltration and excessive runoff. This site naturally delivers water to adjacent sites downstream

by overland flow. Concentrated flow patterns are

common and can easily become rills and gullies

if cover is lost.

Wood products

Considerable amounts of mesquite occupy several present day plant communities. Wood products potential is low on this site. Mesquites

remain small and shrubby because of the soils.

Appendix 4

97

Appendix 4 - Vegetation Production WorksInventory Code _______ Management Unit or Allotment __________________________ Elevation _______ % slope _______ Slope AspSite Write-up Area Number _______ Ecological Site Number _________________ Ecological Site Name _____________________ EcoTransect No. _______ % SWA _______ Soil Map Unit No. _______ Soil Taxon Name _____________________ Soil Phase Texture ClasDate ____________ Recorder ____________ Pasture Number ____________ Estimate Total Production _________________ (lb/ac) VegStratum No. _______ Sampled? (circle) Yes No

Estimated Weight Units by Species (2) Adjustmen

Plant Plant Species Total Wt Wt Plot Plot Adw USpecies Common Wt Unit Meas Size Size Adj ASymbol Name Units Wt gm/lb CF (1) (Optional) P-1 P-2 P-3 P-4 P-5 P-6 P-7 P-8 P-9 P-10 (3) (4) (5) (6) (7) (8) (9

REMARKS:
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Instructions for Filling out the Vegetation Production Worksheet

Be sure to complete the top portion of the worksheet. The following items deal with the vegetation portion of the transect.

Column 1 Enter the acceptable plant symbol from the USDA PLANTS Database at http://plants.usda.gov/. You can even download a

list of species specific for your State. Entering the common name of the plant species is optional.

Column 2 For plots 1 through 10 (P-1 through P-10), enter an estimate of the number of weight units by species occurring in the

appropriate plot(s), or the estimated weight by species occurring in the plots. The weight unit number can be expressed

numerically (e.g. 6, 11.5). If weight by species is recorded, the number entered would be the total estimated weight for

that species. For example, a number of 52 in P-3 would mean that 52 grams or pounds is the estimated weight for that

species in plot 3.

Note: When double sampling is used to determine a correction factor, circle the plot numbers that are clipped.

Column 3 This column represents the summarized total number of weight units or weight by species occurring in plots 1 through

10 as estimated by the data collector.

Column 4 If weight units are entered in the plot data (2) columns, complete this column by entering the weight unit weight by

species used by the data collector. If weight by species was entered in the plot data (2) columns, rather than weight

units, enter 1 in this column.

Column 5 Enter the weight measure unit (grams or pounds) for the weight unit weight shown in column 4 or the summarized

species weight listed in column 3.

Column 6 Enter the plot size used to estimate weight units or weight by species (e.g., plot sizes 9.6 ft2, 96 ft2, or .01 acre).

Column 7 Enter the plot size conversion factor (CF) from Tables 6 or 7 in Chapter 4.

Column 8 Enter the appropriate ADW percent in decimal form, from green weight conversions tables, Appendix 7 (Percent Air-Dry

Weight Conversion Table), or local conversion tables.

Column 9 Complete this column only when the current season’s growth of plant species has been removed by grazing. Enter the

amount in decimal form (e.g., 0.25, 0.40, 0.60), which best reflects the percentage of the “plant remaining” after grazing

utilization has occurred. For example, if a plant species averages 30 percent utilization in the production transect, the

percentage of plant material remaining would be 70 percent. Thus, the adjustment entered for that particular species

would be .70. Utilization may vary through the plots, requiring an estimate of the average use.

Column 10 Enter the cumulative percent of growth, in decimal form, that has occurred up to the time plot data is collected. The

values entered can reflect the growth curves for the site (as listed in some site descriptions) or be based upon locally

developed growth curve data for each species.

When doubling sampling is used to determine a correction factor, data will be recorded in columns 11 through 13; otherwise, these

columns will be left blank.

Column 11 For each plant species occurring in the clipped plots, enter the total estimated weight (to nearest gram or pound) by

multiplying the total weight units by the weight unit weight for all clipped plots.

Column 12 For each plant species occurring in the clipped plots, enter the total clipped (harvested) weight (to nearest gram or

pound) for all clipped plots. 

Column 13 To determine the correction factor, divide column (12) by column (11) for each species and enter to the nearest hundredth.

A factor of 1 indicates the estimates are the same as the clipped weights. A factor below one 1 indicates estimates are

high. A factor above 1 indicates estimates are low. 

Total pounds per acre production result:

Column 14 This column represents the air-dry reconstructed weight in pounds per acre after considering all conversion, correction,

and adjustment factors. Calculate pounds per acre (nearest pound) for each plant species by multiplying the number of

weight units (3), times the weight of the individual weight unit (4), times the plot size conversion factor (7), times the

ADW adjustment (8), times the clipped conversion factor (13). Divide by the utilization adjustment (9), times the growth

adjustment (10). The formula is: 

Pounds per Acre = Columns (3) x (4) x (7) x (8) x (13)

Columns (9) x (10)
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 5

99

Appendix 5 - Foliage Denseness

Classes Utah Juniper

Guide for Determining Current Yield of Utah Juniper in Utah Upland Stony Loam (Juniper) Site

Current Yield Air Dry Pounds

Crown Weight 10 50 100 200 300 400 500

diameter per tree trees trees trees trees trees trees trees

Sparse foliage

1 0.1 1 5 10 20 30 40 50

2 0.3 3 15 30 60 90 120 150

3 0.6 6 30 60 120 180 240 300

4 1.0 10 50 100 200 300 400 500

5 1.3 13 65 130 260 390 520 650

6 1.6 16 80 160 320 480 640 800

7 1.9 19 95 190 380 570 760 950

8 2.3 23 115 230 460 690 920 1150

9 2.6 26 130 260 520 780 1040 1300

10 2.9 29 145 290 580 870 1160 1450

11 3.3 33 165 330 660 990 1320 1650

12 3.6 36 180 360 720 1080 1440 1800

13 4.0 40 200 400 800 1200 1600 2000

14 4.4 44 220 440 880 1320 1760 2200

15 4.7 47 235 470 940 1410 1880 2350

16 5.1 51 255 510 1020 1530 2040 2550

17 5.5 55 275 550 1100 1650 2200

18 5.8 58 290 580 1160 1740 2320

19 6.2 62 310 620 1240 1860 2480

20 6.6 66 330 660 1320 1980 2640

Medium foliage

1 0.1 1 5 10 20 30 40 50

2 0.3 3 15 30 60 90 120 150

3 0.6 6 30 60 120 180 240 300

4 1.0 10 50 100 200 300 400 500

5 1.4 14 70 140 280 420 560 700

6 1.9 19 95 190 380 570 760 950

7 2.5 25 125 250 500 750 1000 1250

8 3.1 31 155 310 620 930 1240 1550

9 3.8 38 190 380 760 1140 1520 1900

10 4.6 46 230 460 920 1380 1840 2300

11 5.4 54 270 540 1080 1620 2160 2700

12 6.2 62 310 620 1240 1860 2480

13 7.2 72 360 720 1440 2160

14 8.1 81 405 810 1620 2430

15 9.1 91 455 910 1820 2730

16 10.2 102 510 1020 2040

17 11.3 113 565 1130 2260

18 12.4 124 620 1240 2480

19 13.6 136 680 1360

20 14.8 148 740 1480
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 5

100

Guide for Determining Current Yield of Utah Juniper (continued)

Current Yield Air Dry Pounds

Crown Weight 10 50 100 200 300 400 500

diameter per tree trees trees trees trees trees trees trees

Dense foliage

1 0.1 1 5 10 20 30 40 50

2 0.3 3 15 30 60 90 120 150

3 0.7 7 35 70 140 210 280 350

4 1.2 12 60 120 240 360 480 600

5 1.9 19 95 190 380 570 760 950

6 2.7 27 135 270 540 810 1080 1350

7 3.6 36 180 360 720 1080 1440 1800

8 4.7 47 235 470 940 1410 1880 2350

9 5.9 59 295 590 1180 1770 2360

10 7.2 72 360 720 1440 2160

11 8.6 86 430 860 1720 2580

12 10.2 102 510 1020 2040

13 11.9 119 595 1190 2380

14 13.7 137 685 1370 2740

15 15.6 156 780 1560

16 17.7 177 885 1770

17 19.9 199 995 1990

18 22.2 222 1110 2220

19 24.6 246 1230 2460

20 27.2 272 1360 2720
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 6

101

Appendix 6 - Examples of

Weight Units

(Reprinted from 190-vi, NRPH, September 1977)

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 7

103

Appendix 7 - Percentage Air-dry

Weight Conversion Table

Percentage of Air-dry Weight in Harvested Plant Material at Various Stages of Growth

Before heading Headed out: Seed ripe: Leaves dry Apparent

Grasses initial growth to boot stage leaf tips stems dormancy

boot stage to flowering drying partly dry

(%) (%) (%) (%) (%)

Cool season 35 45 60 85 95

wheatgrasses

perennial bromes

bluegrasses

prairie junegrass

Warm season 30 45 60 85 95

Tall grasses

bluestems

indiangrass

switchgrass

Midgrasses 40 55 65 90 95

side-oats grama

tabosa

galleta

Short grasses 45 60 80 90 95

blue grama

buffalograss

short three-awns

New leaf and Older and Green Dry

Trees twig growth full size fruit fruit 

until leaves green

are full size leaves

(%) (%) (%) (%)

Evergreen conifers 45 55 35 85

ponderosa pine, slash

pine-longleaf pine

Utah juniper

rocky mountain juniper

spruce

Live oak 40 55 40 85

Deciduous 40 50 35 85

blackjack oak

post oak

hickory

USDA, National Resources Conservation Service, National Range and Pasture Handbook
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 7

104

Percentage of air dry matter (continued)

New leaf and Older and Green Green

Shrubs twig growth until full-size fruit fruit

leaves are full size green leaves

(%) (%) (%) (%)

Evergreen 55 65 35 85

big sagebrush

bitterbrush

ephedra

algerita

gallberry

Deciduous 35 50 30 85

snowberry

rabbitbrush

snakeweed

Gambel oak

mesquite

Yucca and 

yuccca like plants 55 65 35 85

yucca

sotol

saw-palmetto

Initial growth Flowering to Seed ripe Leaves dry Dry

Forbs to flowering seed maturity leaf tips dry stems drying

(%) (%) (%) (%) (%)

Succulent 15 35 60 90 100

violet

waterleaf

buttercup

bluebells

onion, lilies

Leafy 20 40 60 90 100

Lupine

lespedeza

compassplant

balsamroot

tickclover

Fibrous leaves

or mat 30 50 75 90 100

phlox, mat eriogonum

pussytoes

Succulents New growth pads and fruit Older pads Old growth in dry years

(%) (%) (%)

Prickly pear and barrel cactus 10 10 15+

Cholla cactus 20 25 30+
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 8

105

Type Subtype Code

Sand Sage 4046

Chamise 4051

Manzanita 4052

Ceanothus 4053

Shinnery Oak 4054

Chaparral 4055

Mountain Mahogany 4056

Bitterbrush 4057

Oakbrush 4058

Serviceberry 4059

Mountain shrub 4060

Blackbrush 4061

Cactus 4062

Joshua Tree 4063

Yucca 4064

White Thorn 4065

Paloverde Cerci 4066

Bursage FRDE-FRD 4067

Catclaw 4068

Sotol 4069

Mariola 4070

Snakeweed 4071

Fringed Sagebrush 4072

Clubmoss 4073

Willow 4074

Turpentine Brush 4075

Burroweed HATE 4076

Mormon Tea 4077

Skunk Bush 4078

Ocotilla 4079

Sacahuiste 4080

Alder 4081

Snowberry 4082

Other Shrub 4999

Appendix 8 - Vegetation Types and

Subtypes

Information Resource

Management (IRM) Codes for

Vegetation Types and Subtypes

Type Subtype Code

Annual Forbs 0000

Filaree 0001

Halogeton 0002

Other Forbs 0999

Grass 1000

Short Grass 1001

Mid Grass 1002 

Tall Grass 1003 

Crested Wheat Grass 1004

Mixed Grass Seeding 1005

Other Grass 1999

Grasslike Sedge 2001

Rush 2002

Other Grasslike 2999

Perennial Forbs 3001

Shrub 4000

Black Greasewood 4001

Bailey Greasewood 4002

Creosote Bush 4011

Tarbush 4012 

Broom Dalea 4013

Winterfat 4015

Mesquite 4021

Shadscale 4031

Nuttal Saltbush 4032

Mat Saltbush 4033

Fourwing Saltbush 4034

Other Saltbush 4035

Desert Saltbush AT 4036

Mixed Desert Shrub 4037

Big Sagebrush 4041

Low Sagebrush 4042

Black Sagebrush 4043

Other Sagebrush 4044

Rabbitbrush 4045
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 8

106

Information Resource Management

(IRM) Codes for Vegetation Types

and Subtypes (continued)

Type Subtype Code

Broadleaf Trees 5000

Willow 5074

Desert Willow 5075

Birch AK 5077

Balsam Pop - Cottoseed 5079

Red Alder 5081

Poplar - Birch 5082

Aspen 5083

Calif Black Oak 5084

Cottonwood 5085

Maple 5086

Oregon White Oak 5087

Madrone 5088

Tan Oak 5089

Noncommercial

Hardwood 5098

Other Broadleaf Tree 5999

Conifers 6000

Douglas Fir 6001

Doug Fir - Hemlock 6002

Port Orford Cedar 6003

Doug Fir - White Fir 6004

Ponderosa Pine 6011

Jeffery Pine 6012 

Pond-Sugar-Pine-Fir 6013

Sugar Pine 6014 

Incense Cedar 6015 

Cypress 6019

Western White Pine 6021

White Fir 6031

Red Fir 6032

Grand Fir 6033

Pacific Silver Fir 6034

Engel Spruce 6035

Engel SpruceSubalp Fir 6036

White Spruce 6037

Blue Spruce 6038

Noble Fir 6039

Western Red Cedar 6041

Sitka Spruce 6042

Type Subtype Code

Black Spruce 6043

Mountain Hemlock 6047

Western Hemlock 6048

Alaskan Cedar 6049

Western Larch 6055

Grand FirLarch-Doug Fir 6056

Pond PineLarch-Doug Fir 6057

Larch -TamarackAlaska 6058

Lodgepole Pine 6061

Redwood 6071

Noncommerical 

Softwood 6090

Coulter Pine 6091

Digger Pine 6092

Pinyon-Juniper 6093

Knobcone Pine 6094

Bristlecone Pine 6095

Whitebk & Limber 6096

Pinyon 6097

Juniper 6098

Commercial

Nonstocked 6099

Other Conifer 6999

Cryptogams 7000

Lichen-Moss 7001

Moss 7002

Lichen 7003

Fern 7004 

Other 7999

Barren 8000

Annual grass 9000

Cheatgrass 9001

Medusahead Rye 9002

Red Brome 9003

Three-Awn 9005

Six Weeks grama 9006

Other 9999
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 9

107

Appendix 9 - Similarity Index Form 

Management Unit or Allotment Examiner 

Ecological Site Location 

Reference Plant Community Date

AB C D E

Plant Species Name Production/acres in Annual production Pounds

Group reference plant community in lb/acre (actual or allowable

(from ecological site reconstructed

description)

TOTALS 

SIMILARITY INDEX to Native Midgrass Community = 

(Total of E divided by total of C)

INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 10

109

Appendix 10 - Data Element Codes

A complete listing of all data elements can be found in the Corporate Data Dictionary at:

http://sc2962.sc.blm.gov/datashopper/default.asp

Data Element Landform 5132

Code Landform Name Description

ALF ALLUVIAL FAN The fan like deposit of a steam where it issues from a gorge upon a plain.

ARY ARROYO

BAL BADLANDS An area characterized by the intricate and sharp erosional sculpture of generally

weak rocks forming nearly horizontal beds.

BNC BENCH Level narrow platform breaking up slope

BTT BUTTE An isolated hill or small mountain with steep sides. With a smaller summit

area than a mesa.

CAN CANYON A deep narrow valley with precipitous sides where downward cutting of the

stream greatly exceeds weathering.

CHL CHANNEL The bed of a single or braided watercourse that is commonly barren of

vegetation.

CIN CINDER CONE

CRT CREST The very narrow commonly linear top of an erosional ridge, hill, mountain.

DMR DRY MEADOW RIPARIAN

FAN FAN PIEDMONT The most extensive major landform of most piedmont slopes, formed by the

lateral coalescense of mountain-front alluvial fans downslope into one generally

smooth slope without the transverse undulations of the semi-conical alluvial

fans by accretion of fans aprons.

FPL FLOOD PLAIN A flat surface that may be submerged by waterflow built up by stream deposition.

GUL GULLY Gullies, arroyos, wadis, and gulches.

HBK HOGBACK A ridge of land formed by the outcropping edges of tilted strata; a ridge with

a sharp summit and steeply sloping sides.

ISR INTERMITTENT STREAM
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 10

110

Code Landform Name Description

ITB INTERMONTANE BASIN A relatively small structural depression within a mountain range that is partly

filled with alluviam and commonly drains externally through a narrower 

mountain valley.

MAN LAVA FLOW- NONVEGETATED

MAV LAVA FLOW- VEGETATED

MSA MESA An isolated hill or mountain having abrupt or steeply sloping sides and a level top.

MTN MOUNTAIN A steep elevation with a restricted summit area projecting 1000 feet or more 

above the surrounding land surface.

OLR LAKE RIPARIAN

ORR RESERVOIR RIPARIAN

OSR STREAM RIPARIAN

PED PEDIMENT A broad, gently sloping bedrock surface with low relief that is situated at the

foot of a much steeper mountain slope.

PYA PLAYA An undrained basin that becomes at times a shallow lake on which evaporation

may leave a deposit of salt.

RAV RAVINE Larger than a gully, smaller than a valley.

RDG RIDGE A range of hills or mountains or the upper part of such a range; an extended

elevation between valleys.

SDL SADDLE A ridge connecting two higher elevations; a low point in the crestline of a ridge.

SDN SAND DUNE Sand dunes and sand hills.

SRP SCARP A line of cliffs produced by faulting or erosion.

SUM SUMMIT The flattish top of a an erosional fan remnant, hill, or mountain.

SWL SWALE

TRC TERRACE A level and ordinarily rather narrow plain usually with a steep front bordering

a river, a lake, or the sea.

UPL UPLANDS High land especially far from the sea; ground elevated above the lowlands 

along rivers.

VAL VALLEY An elongated depression of the earth’s surface commonly situated between ranges

or hills or mountains and often comprising a drainage area and an area of 

generally flat land and drained or watered by a large river and its tributary streams.

WMR WET MEADOW- RIPARIAN
INVENTORY AND MONITORING Technical Reference 1734–7 • Ecological Site Inventory

Appendix 10

111

Soil Phase - Soil Phase -

Texture Class 4991 Texture Modifier data element 4992

Code Texture Class Code Texture Modifier 

C CLAY BY Bouldery

CL CLAY LOAM BYV Very Bouldery 

COS COARSE SAND BYX Extremely Bouldery

COSL COARSE SANDY LOAM CB Cobbly

FS FINE SAND CBA Angular Cobbly

FSL FINE SANDY LOAM CBV Very Cobbly

L LOAM CBX Extremely Cobbly

LCOS LOAMY COARSE SAND CN Chennery

LFS LOAMY FINE SAND CNV Very Chennery

LS LOAMY SAND CNX Extremely Chennery

LVSF LOAMY VERY FINE SAND CR Cherty

S SAND CRC Coarse Cherty

SC SANDY CLAY CRV Very Cherty

SCL SANDY CLAY LOAM CRX Extremely Cherty

SI SILT FL Flaggy

SIC SILTY CLAY FLV Very Flaggy

SICL SILTY CLAY LOAM FLX Extremely Flaggy

SIL SILT LOAM GR Gravelly

SL SANDY LOAM GRC Coarse Gravelly

VFS VERY FINE SAND GRF Fine Gravelly

VFSL VERY FINE SANDY LOAM GRV Very Gravelly

GRX Extremely Gravelly

MK Mucky

PT peaty

RB Rubbly

SH Shaly

SHV Very Shaly

SHX Extremely Shaly

SR Stratified

ST Stony

STV Very Stony

STX Extremely Stony

SY Slaty

SYV Very Slaty

SYX Extremely Slaty

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Dec. 2001 Final

Inventory and Monitoring—Technical Reference 1734-7

Ecological Site Inventory

U.S. Department of the Interior

Bureau of Land Management

National Science and Technology Center

P.O. Box 25047

Denver, CO 80225-0047

BLM/ST/ST-01/003+1734

Technical Reference 1734-7 describes the procedures for planning and conducting ecological site inventories

and for documenting ecological site descriptions. It includes detailed information about mapping ecological

sites and plant communities. It includes information about the collection of vegetation production data and

the use of the data for determining a similarity index. It discusses plant succession and state and transition

pathways.

vegetation production, soil map units, vegetation mapping, ecological sites, state and transition pathways, site write-up area, stratification, vegetation subtypes, similarity index

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128 including covers

6. AUTHOR(S)

Edward F. Habich

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The mention of trade names or commercial products does not constitute endorsement or recommendation 

for use by the Federal Government.
U.S. Department of the Interior

Bureau of Land Management